infinite loop - Page 322

JMaghreb 2012 Trip Report

- by arungupta

JMaghreb is the inaugural Java conference organized by Morocco JUG. It is the biggest Java conference in Maghreb (5 countries in North West Africa). Oracle was the exclusive platinum sponsor with several others. The registrations had to be closed at 1412 for the free conference and several folks were already on the waiting list. Rabat with 531 registrations and Casablanca with 426 were the top cities. Some statistics ... 850+ attendees over 2 days, 500+ every day 30 sessions were delivered by 18 speakers from 10 different countries 10 sessions in French and 20 in English 6 of the speakers spoke at JavaOne 2012 8 will be at Devoxx Attendees from 5 different countries and 57 cities in Morocco 40.9% qualified them as professional and rest as students Topics ranged from HTML5, Java EE 7, ADF, JavaFX, MySQL, JCP, Vaadin, Android, Community, JCP Java EE 6 hands-on lab was sold out within 7 minutes and JavaFX in 12 minutes I gave the keynote along with Simon Ritter which was basically a recap of the Strategy and Technical keynotes presented at JavaOne 2012. An informal survey during the keynote showed the following numbers: 25% using NetBeans, 90% on Eclipse, 3 on JDeveloper, 1 on IntelliJ About 10 subscribers to free online Java magazine. This digital magazine is a comprehensive source of information for everything Java - subscribe for free!! About 10-15% using Java SE 7. Download JDK 7 and get started today! Even JDK 8 builds have been available for a while now. My second talk explained the core concepts of WebSocket and how JSR 356 is providing a standard API to build WebSocket-driven applications in Java EE 7. TOTD #183 explains how you can easily get started with WebSocket in GlassFish 4. The complete slide deck is available: Next day started with a community keynote by Sonya Barry. Some of us live the life of JCP, JSR, EG, EC, RI, etc every day, but not every body is. To address that, Sonya prepared an excellent introductory presentation providing an explanation of these terms and how java.net infrastructure supports Java development. The registration for the lab showed there is a definite demand for these technologies in this part of the world. I delivered the Java EE 6 hands-on lab to a packed room of about 120 attendees. Most of the attendees were able to progress and follow the lab instructions. Some of the attendees did not have a laptop but were taking extensive notes on paper notepads. Several attendees were already using Java EE 6 in their projects and typically they are the ones asking deep dive questions. Also gave out three copies of my recently released Java EE 6 Pocket Guide and new GlassFish t-shirts. Definitely feels happy to coach ~120 more Java developers learn standards-based enterprise Java programming. I also participated in a JCP BoF along with Werner, Sonya, and Badr. Adotp-a-JSR, java.net infrastructure, how to file a JSR, what is an RI, and other similar topics were discussed in a candid manner. You can follow @JMaghrebConf or check out their facebook page. java.net published a timely conversation with Badr El Houari - the fearless leader of the Morocco JUG team. Did you know that Morocco JUG stood for JCP EC elections (ADD LINK) ? Even though they did not get elected but did fairly well. Now some sample tweets from #JMaghreb ... #JMaghreb is over. Impressive for a first edition! Thanks @badrelhouari and all the @MoroccoJUG team ! Since you @speakjava : System.out.println("Thank you so much dear Tech Evangelist ! The JavaFX was pretty amazing !!! "); #JMaghreb @YounesVendetta @arungupta @JMaghrebConf Right ! hope he will be back to morocco again and again .. :) @Alji_ @arungupta @JMaghrebConf That dude is a genius ;) Put it on your wall :p @arungupta rocking Java EE 6 at @JMaghrebConf #Java #JavaEE #JMaghreb http://t.co/isl0Iq5p @sonyabarry you are an awesome speaker ;-) #JMaghreb rich more than 550 attendees in day one. Expecting more tomorrow! ongratulations @badrelhouari the organisation was great! The talks were pretty interesting, and the turnout was surprising at #JMaghreb! #JMaghreb is truly awesome... The speakers are unbelievable ! #JavaFX... Just amazing #JMaghreb Charmed by the talk about #javaFX ( nodes architecture, MVC, Lazy loading, binding... ) gotta start using it intead of SWT. #JMaghreb JavaFX is killing JFreeChart. It supports Charts a lot of kind of them ... #JMaghreb The british man is back #JMaghreb I do like him!! #JMaghreb @arungupta rocking @JMaghrebConf. pic.twitter.com/CNohA3PE @arungupta Great talk about the future of Java EE (JEE 7 & JEE 8) Thank you. #JMaghreb JEE7 more mooore power , leeess less code !! #JMaghreb They are simplifying the existing API for Java Message Service 2.0 #JMaghreb good to know , the more the code is simplified the better ! The Glassdoor guy #arungupta is doing it RIGHT ! #JMaghreb Great presentation of The Future of the Java Platform: Java EE 7, Java SE 8 & Beyond #jMaghreb @arungupta is a great Guy apparently #JMaghreb On a personal front, the hotel (Soiftel Jardin des Roses) was pretty nice and the location was perfect. There was a 1.8 mile loop dirt trail right next to it so I managed to squeeze some runs before my upcoming marathon. Also enjoyed some great Moroccan cuisine - Couscous, Tajine, mint tea, and moroccan salad. Visit to Kasbah of the Udayas, Hassan II (one of the tallest mosque in the world), and eating in a restaurant in a kasbah are some of the exciting local experiences. Now some pictures from the event (and around the city) ... And the complete album: Many thanks to Badr, Faisal, and rest of the team for organizing a great conference. They are already thinking about how to improve the content, logisitics, and flow for the next year. I'm certainly looking forward to JMaghreb 2.0 :-)

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The DOS DEBUG Environment

- by MarkPearl

Today I thought I would go back in time and have a look at the DEBUG command that has been available since the beginning of dawn in DOS, MS-DOS and Microsoft Windows. up to today I always knew it was there, but had no clue on how to use it so for those that are interested this might be a great geek party trick to pull out when you want the awe the younger generation and want to show them what “real” programming is about. But wait, you will have to do it relatively quickly as it seems like DEBUG was finally dumped from the Windows group in Windows 7. Not to worry, pull out that Windows XP box which will get you even more geek points and you can still poke DEBUG a bit. So, for those that are interested and want to find out a bit about the history of DEBUG read the wiki link here. That all put aside, lets get our hands dirty.. How to Start DEBUG in Windows Make sure your version of Windows supports DEBUG. Open up a console window Make a directory where you want to play with debug – in my instance I called it C221 Enter the directory and type Debug You will get a response with a – as illustrated in the image below… The commands available in DEBUG There are several commands available in DEBUG. The most common ones are A (Assemble) R (Register) T (Trace) G (Go) D (Dump or Display) U (Unassemble) E (Enter) P (Proceed) N (Name) L (Load) W (Write) H (Hexadecimal) I (Input) O (Output) Q (Quit) I am not going to cover all these commands, but what I will do is go through a few of them briefly. A is for Assemble Command (to write code) The A command translates assembly language statements into machine code. It is quite useful for writing small assembly programs. Below I have written a very basic assembly program. The code typed out is as follows mov ax,0015 mov cx,0023 sub cx,ax mov [120],al mov cl,[120]A nop R is for Register (to jump to a point in memory) The r command turns out to be one of the most frequent commands you will use in DEBUG. It allows you to view the contents of registers and to change their values. It can be used with the following combinations… R – Displays the contents of all the registers R f – Displays the flags register R register_name – Displays the contents of a specific register All three methods are illustrated in the image above T is for Trace (To execute a program step by step) The t command allows us to execute the program step by step. Before we can trace the program we need to point back to the beginning of the program. We do this by typing in r ip, which moves us back to memory point 100. We then type trace which executes the first line of code (line 100) (As shown in the image below starting from the red arrow). You can see from the above image that the register AX now contains 0015 as per our instruction mov ax,0015 You can also see that the IP points to line 0103 which has the MOV CX,0023 command If we type t again it will now execute the second line of the program which moves 23 in the cx register. Again, we can see that the line of code was executed and that the CX register now holds the value of 23. What I would like to highlight now is the section underlined in red. These are the status flags. The ones we are going to look at now are 1st (NV), 4th (PL), 5th (NZ) & 8th (NC) NV means no overflow, the alternate would be OV PL means that the sign of the previous arithmetic operation was Plus, the alternate would be NG (Negative) NZ means that the results of the previous arithmetic operation operation was Not Zero, the alternate would be ZR NC means that No final Carry resulted from the previous arithmetic operation. CY means that there was a final Carry. We could now follow this process of entering the t command until the entire program is executed line by line. G is for Go (To execute a program up to a certain line number) So we have looked at executing a program line by line, which is fine if your program is minuscule BUT totally unpractical if we have any decent sized program. A quicker way to run some lines of code is to use the G command. The ‘g’ command executes a program up to a certain specified point. It can be used in connection with the the reset IP command. You would set your initial point and then run the G command with the line you want to end on. P is for Proceed (Similar to trace but slightly more streamlined) Another command similar to trace is the proceed command. All that the p command does is if it is called and it encounters a CALL, INT or LOOP command it terminates the program execution. In the example below I modified our example program to include an int 20 at the end of it as illustrated in the image below… Then when executing the code when I encountered the int 20 command I typed the P command and the program terminated normally (illustrated below). D is for Dump (or for those more polite Display) So, we have all these assembly lines of code, but if you have ever opened up an exe or com file in a text/hex editor, it looks nothing like assembly code. The D command is a way that we can see what our code looks like in memory (or in a hex editor). If we examined the image above, we can see that Debug is storing our assembly code with each instruction following immediately after the previous one. For instance in memory address 110 we have int and 111 we have 20. If we examine the dump of memory we can see at memory point 110 CD is stored and at memory point 111 20 is stored. U is for Unassemble (or Convert Machine code to Assembly Code) So up to now we have gone through a bunch of commands, but probably one of the most useful is the U command. Let’s say we don’t understand machine code so well and so instead we want to see it in its equivalent assembly code. We can type the U command followed by the start memory point, followed by the end memory point and it will show us the assembly code equivalent of the machine code. E is for a bunch of things… The E command can be used for a bunch of things… One example is to enter data or machine code instructions directly into memory. It can also be used to display the contents of memory locations. I am not going to worry to much about it in this post. N / L / W is for Name, Load & Write So we have written out assembly code in debug, and now we want to save it to disk, or write it as a com file or load it. This is where the N, L & W command come in handy. The n command is used to give a name to the executable program file and is pretty simple to use. The w command is a bit trickier. It saves to disk all the memory between point bx and point cx so you need to specify the bx memory address and the cx memory address for it to write your code. Let’s look at an example illustrated below. You do this by calling the r command followed by the either bx or cx. We can then go to the directory where we were working and will see the new file with the name we specified. The L command is relatively simple. You would first specify the name of the file you would like to load using the N command, and then call the L command. Q is for Quit The last command that I am going to write about in this post is the Q command. Simply put, calling the Q command exits DEBUG. Commands we did not Cover Out of the standard DEBUG commands we covered A, T, G, D, U, E, P, R, N, L & W. The ones we did not cover were H, I & O – I might make mention of these in a later post, but for the basics they are not really needed. Some Useful Resources Please note this post is based on the COS2213 handouts for UNISA A Guide to DEBUG - http://mirror.href.com/thestarman/asm/debug/debug.htm#NT

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Using Lightbox with _Screen

Although, I have to admit that I discovered Bernard Bout's ideas and concepts about implementing a lightbox in Visual FoxPro quite a while ago, there was no "spare" time in active projects that allowed me to have a closer look into his solution(s). Luckily, these days I received a demand to focus a little bit more on this. This article describes the steps about how to integrate and make use of Bernard's lightbox class in combination with _Screen in Visual FoxPro. The requirement in this project was to be able to visually lock the whole application (_Screen area) and guide the user to an information that should not be ignored easily. Depending on the importance any current user activity should be interrupted and focus put onto the notification. Getting the "meat", eh, source code Please check out Bernard's blog on Foxite directly in order to get the latest and greatest version. As time of writing this article I use version 6.0 as described in this blog entry: The Fastest Lightbox Ever The Lightbox class is sub-classed from the imgCanvas class from the GdiPlusX project on VFPx and therefore you need to have the source code of GdiPlusX as well, and integrate it into your development environment. The version I use is available here: Release GDIPlusX 1.20 As soon as you open the bbGdiLightbox class the first it, VFP might ask you to update the reference to the gdiplusx.vcx. As we have the sources, no problem and you have access to Bernard's code. The class itself is pretty easy to understand, some properties that you do not need to change and three methods: Setup(), ShowLightbox() and BeforeDraw() The challenge - _Screen or not? Reading Bernard's article about the fastest lightbox ever, he states the following: "The class will only work on a form. It will not support any other containers" Really? And what about _Screen? Isn't that a form class, too? Yes, of course it is but nonetheless trying to use _Screen directly will fail. Well, let's have look at the code to see why: WITH This .Left = 0 .Top = 0 .Height = ThisForm.Height .Width = ThisForm.Width .ZOrder(0) .Visible = .F.ENDWITH During the setup of the lightbox as well as while capturing the image as replacement for your forms and controls, the object reference Thisform is used. Which is a little bit restrictive to my opinion but let's continue. The second issue lies in the method ShowLightbox() and introduced by the call of .Bitmap.FromScreen(): Lparameters tlVisiblilty* tlVisiblilty - show or hide (T/F)* grab a screen dump with controlsIF tlVisiblilty Local loCaptureBmp As xfcBitmap Local lnTitleHeight, lnLeftBorder, lnTopBorder, lcImage, loImage lnTitleHeight = IIF(ThisForm.TitleBar = 1,Sysmetric(9),0) lnLeftBorder = IIF(ThisForm.BorderStyle < 2,0,Sysmetric(3)) lnTopBorder = IIF(ThisForm.BorderStyle < 2,0,Sysmetric(4)) With _Screen.System.Drawing loCaptureBmp = .Bitmap.FromScreen(ThisForm.HWnd,; lnLeftBorder,; lnTopBorder+lnTitleHeight,; ThisForm.Width ,; ThisForm.Height) ENDWITH * save it to a property This.capturebmp = loCaptureBmp ThisForm.SetAll("Visible",.F.) This.DraW() This.Visible = .T.ELSE ThisForm.SetAll("Visible",.T.) This.Visible = .F.ENDIF My first trials in using the class ended in an exception - GdiPlusError:OutOfMemory - thrown by the Bitmap object. Frankly speaking, this happened mainly because of my lack of knowledge about GdiPlusX. After reading some documentation, especially about the FromScreen() method I experimented a little bit. Capturing the visible area of _Screen actually was not the real problem but the dimensions I specified for the bitmap. The modifications - step by step First of all, it is to get rid of restrictive object references on Thisform and to change them into either This.Parent or more generic into This.oForm (even better: This.oControl). The Lightbox.Setup() method now sets the necessary object reference like so: *====================================================================* Initial setup* Default value: This.oControl = "This.Parent"* Alternative: This.oControl = "_Screen"*====================================================================With This .oControl = Evaluate(.oControl) If Vartype(.oControl) == T_OBJECT .Anchor = 0 .Left = 0 .Top = 0 .Width = .oControl.Width .Height = .oControl.Height .Anchor = 15 .ZOrder(0) .Visible = .F. EndIfEndwith Also, based on other developers' comments in Bernard articles on his lightbox concept and evolution I found the source code to handle the differences between a form and _Screen and goes into Lightbox.ShowLightbox() like this: *====================================================================* tlVisibility - show or hide (T/F)* grab a screen dump with controls*====================================================================Lparameters tlVisibility Local loControl m.loControl = This.oControl If m.tlVisibility Local loCaptureBmp As xfcBitmap Local lnTitleHeight, lnLeftBorder, lnTopBorder, lcImage, loImage lnTitleHeight = Iif(m.loControl.TitleBar = 1,Sysmetric(9),0) lnLeftBorder = Iif(m.loControl.BorderStyle < 2,0,Sysmetric(3)) lnTopBorder = Iif(m.loControl.BorderStyle < 2,0,Sysmetric(4)) With _Screen.System.Drawing If Upper(m.loControl.Name) == Upper("Screen") loCaptureBmp = .Bitmap.FromScreen(m.loControl.HWnd) Else loCaptureBmp = .Bitmap.FromScreen(m.loControl.HWnd,; lnLeftBorder,; lnTopBorder+lnTitleHeight,; m.loControl.Width ,; m.loControl.Height) EndIf Endwith * save it to a property This.CaptureBmp = loCaptureBmp m.loControl.SetAll("Visible",.F.) This.Draw() This.Visible = .T. Else This.CaptureBmp = .Null. m.loControl.SetAll("Visible",.T.) This.Visible = .F. Endif {loadposition content_adsense} Are we done? Almost... Although, Bernard says it clearly in his article: "Just drop the class on a form and call it as shown." It did not come clear to my mind in the first place with _Screen, but, yeah, he is right. Dropping the class on a form provides a permanent link between those two classes, it creates a valid This.Parent object reference. Bearing in mind that the lightbox class can not be "dropped" on the _Screen, we have to create the same type of binding during runtime execution like so: *====================================================================* Create global lightbox component*==================================================================== Local llOk, loException As Exception m.llOk = .F. m.loException = .Null. If Not Vartype(_Screen.Lightbox) == "O" Try _Screen.AddObject("Lightbox", "bbGdiLightbox") Catch To m.loException Assert .F. Message m.loException.Message EndTry EndIf m.llOk = (Vartype(_Screen.Lightbox) == "O")Return m.llOk Through runtime instantiation we create a valid binding to This.Parent in the lightbox object and the code works as expected with _Screen. Ease your life: Use properties instead of constants Having a closer look at the BeforeDraw() method might wet your appetite to simplify the code a little bit. Looking at the sample screenshots in Bernard's article you see several forms in different colors. This got me to modify the code like so: *====================================================================* Apply the actual lightbox effect on the captured bitmap.*====================================================================If Vartype(This.CaptureBmp) == T_OBJECT Local loGfx As xfcGraphics loGfx = This.oGfx With _Screen.System.Drawing loGfx.DrawImage(This.CaptureBmp,This.Rectangle,This.Rectangle,.GraphicsUnit.Pixel) * change the colours as needed here * possible colours are (220,128,0,0),(220,0,0,128) etc. loBrush = .SolidBrush.New(.Color.FromArgb( ; This.Opacity, .Color.FromRGB(This.BorderColor))) loGfx.FillRectangle(loBrush,This.Rectangle) EndwithEndif Create an additional property Opacity to specify the grade of translucency you would like to have without the need to change the code in each instance of the class. This way you only need to change the values of Opacity and BorderColor to tweak the appearance of your lightbox. This could be quite helpful to signalize different levels of importance (ie. green, yellow, orange, red, etc...) of notifications to the users of the application. Final thoughts Using the lightbox concept in combination with _Screen instead of forms is possible. Already Jim Wiggins comments in Bernard's article to loop through the _Screen.Forms collection in order to cascade the lightbox visibility to all active forms. Good idea. But honestly, I believe that instead of looping all forms one could use _Screen.SetAll("ShowLightbox", .T./.F., "Form") with Form.ShowLightbox_Access method to gain more speed. The modifications described above might provide even more features to your applications while consuming less resources and performance. Additionally, the restrictions to capture only forms does not exist anymore. Using _Screen you are able to capture and cover anything. The captured area of _Screen does not include any toolbars, docked windows, or menus. Therefore, it is advised to take this concept on a higher level and to combine it with additional classes that handle the state of toolbars, docked windows and menus. Which I did for the customer's project.

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Replication Services as ETL extraction tool

- by jorg

In my last blog post I explained the principles of Replication Services and the possibilities it offers in a BI environment. One of the possibilities I described was the use of snapshot replication as an ETL extraction tool: “Snapshot Replication can also be useful in BI environments, if you don’t need a near real-time copy of the database, you can choose to use this form of replication. Next to an alternative for Transactional Replication it can be used to stage data so it can be transformed and moved into the data warehousing environment afterwards. In many solutions I have seen developers create multiple SSIS packages that simply copies data from one or more source systems to a staging database that figures as source for the ETL process. The creation of these packages takes a lot of (boring) time, while Replication Services can do the same in minutes. It is possible to filter out columns and/or records and it can even apply schema changes automatically so I think it offers enough features here. I don’t know how the performance will be and if it really works as good for this purpose as I expect, but I want to try this out soon!” Well I have tried it out and I must say it worked well. I was able to let replication services do work in a fraction of the time it would cost me to do the same in SSIS. What I did was the following: Configure snapshot replication for some Adventure Works tables, this was quite simple and straightforward. Create an SSIS package that executes the snapshot replication on demand and waits for its completion. This is something that you can’t do with out of the box functionality. While configuring the snapshot replication two SQL Agent Jobs are created, one for the creation of the snapshot and one for the distribution of the snapshot. Unfortunately these jobs are asynchronous which means that if you execute them they immediately report back if the job started successfully or not, they do not wait for completion and report its result afterwards. So I had to create an SSIS package that executes the jobs and waits for their completion before the rest of the ETL process continues. Fortunately I was able to create the SSIS package with the desired functionality. I have made a step-by-step guide that will help you configure the snapshot replication and I have uploaded the SSIS package you need to execute it. Configure snapshot replication The first step is to create a publication on the database you want to replicate. Connect to SQL Server Management Studio and right-click Replication, choose for New.. Publication… The New Publication Wizard appears, click Next Choose your “source” database and click Next Choose Snapshot publication and click Next You can now select tables and other objects that you want to publish Expand Tables and select the tables that are needed in your ETL process In the next screen you can add filters on the selected tables which can be very useful. Think about selecting only the last x days of data for example. Its possible to filter out rows and/or columns. In this example I did not apply any filters. Schedule the Snapshot Agent to run at a desired time, by doing this a SQL Agent Job is created which we need to execute from a SSIS package later on. Next you need to set the Security Settings for the Snapshot Agent. Click on the Security Settings button. In this example I ran the Agent under the SQL Server Agent service account. This is not recommended as a security best practice. Fortunately there is an excellent article on TechNet which tells you exactly how to set up the security for replication services. Read it here and make sure you follow the guidelines! On the next screen choose to create the publication at the end of the wizard Give the publication a name (SnapshotTest) and complete the wizard The publication is created and the articles (tables in this case) are added Now the publication is created successfully its time to create a new subscription for this publication. Expand the Replication folder in SSMS and right click Local Subscriptions, choose New Subscriptions The New Subscription Wizard appears Select the publisher on which you just created your publication and select the database and publication (SnapshotTest) You can now choose where the Distribution Agent should run. If it runs at the distributor (push subscriptions) it causes extra processing overhead. If you use a separate server for your ETL process and databases choose to run each agent at its subscriber (pull subscriptions) to reduce the processing overhead at the distributor. Of course we need a database for the subscription and fortunately the Wizard can create it for you. Choose for New database Give the database the desired name, set the desired options and click OK You can now add multiple SQL Server Subscribers which is not necessary in this case but can be very useful. You now need to set the security settings for the Distribution Agent. Click on the …. button Again, in this example I ran the Agent under the SQL Server Agent service account. Read the security best practices here Click Next Make sure you create a synchronization job schedule again. This job is also necessary in the SSIS package later on. Initialize the subscription at first synchronization Select the first box to create the subscription when finishing this wizard Complete the wizard by clicking Finish The subscription will be created In SSMS you see a new database is created, the subscriber. There are no tables or other objects in the database available yet because the replication jobs did not ran yet. Now expand the SQL Server Agent, go to Jobs and search for the job that creates the snapshot: Rename this job to “CreateSnapshot” Now search for the job that distributes the snapshot: Rename this job to “DistributeSnapshot” Create an SSIS package that executes the snapshot replication We now need an SSIS package that will take care of the execution of both jobs. The CreateSnapshot job needs to execute and finish before the DistributeSnapshot job runs. After the DistributeSnapshot job has started the package needs to wait until its finished before the package execution finishes. The Execute SQL Server Agent Job Task is designed to execute SQL Agent Jobs from SSIS. Unfortunately this SSIS task only executes the job and reports back if the job started succesfully or not, it does not report if the job actually completed with success or failure. This is because these jobs are asynchronous. The SSIS package I’ve created does the following: It runs the CreateSnapshot job It checks every 5 seconds if the job is completed with a for loop When the CreateSnapshot job is completed it starts the DistributeSnapshot job And again it waits until the snapshot is delivered before the package will finish successfully Quite simple and the package is ready to use as standalone extract mechanism. After executing the package the replicated tables are added to the subscriber database and are filled with data: Download the SSIS package here (SSIS 2008) Conclusion In this example I only replicated 5 tables, I could create a SSIS package that does the same in approximately the same amount of time. But if I replicated all the 70+ AdventureWorks tables I would save a lot of time and boring work! With replication services you also benefit from the feature that schema changes are applied automatically which means your entire extract phase wont break. Because a snapshot is created using the bcp utility (bulk copy) it’s also quite fast, so the performance will be quite good. Disadvantages of using snapshot replication as extraction tool is the limitation on source systems. You can only choose SQL Server or Oracle databases to act as a publisher. So if you plan to build an extract phase for your ETL process that will invoke a lot of tables think about replication services, it would save you a lot of time and thanks to the Extract SSIS package I’ve created you can perfectly fit it in your usual SSIS ETL process.

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Using SQL Execution Plans to discover the Swedish alphabet

- by Rob Farley

SQL Server is quite remarkable in a bunch of ways. In this post, I’m using the way that the Query Optimizer handles LIKE to keep it SARGable, the Execution Plans that result, Collations, and PowerShell to come up with the Swedish alphabet. SARGability is the ability to seek for items in an index according to a particular set of criteria. If you don’t have SARGability in play, you need to scan the whole index (or table if you don’t have an index). For example, I can find myself in the phonebook easily, because it’s sorted by LastName and I can find Farley in there by moving to the Fs, and so on. I can’t find everyone in my suburb easily, because the phonebook isn’t sorted that way. I can’t even find people who have six letters in their last name, because also the book is sorted by LastName, it’s not sorted by LEN(LastName). This is all stuff I’ve looked at before, including in the talk I gave at SQLBits in October 2010. If I try to find everyone who’s names start with F, I can do that using a query a bit like: SELECT LastName FROM dbo.PhoneBook WHERE LEFT(LastName,1) = 'F'; Unfortunately, the Query Optimizer doesn’t realise that all the entries that satisfy LEFT(LastName,1) = 'F' will be together, and it has to scan the whole table to find them. But if I write: SELECT LastName FROM dbo.PhoneBook WHERE LastName LIKE 'F%'; then SQL is smart enough to understand this, and performs an Index Seek instead. To see why, I look further into the plan, in particular, the properties of the Index Seek operator. The ToolTip shows me what I’m after: You’ll see that it does a Seek to find any entries that are at least F, but not yet G. There’s an extra Predicate in there (a Residual Predicate if you like), which checks that each LastName is really LIKE F% – I suppose it doesn’t consider that the Seek Predicate is quite enough – but most of the benefit is seen by its working out the Seek Predicate, filtering to just the “at least F but not yet G” section of the data. This got me curious though, particularly about where the G comes from, and whether I could leverage it to create the Swedish alphabet. I know that in the Swedish language, there are three extra letters that appear at the end of the alphabet. One of them is ä that appears in the word Västerås. It turns out that Västerås is quite hard to find in an index when you’re looking it up in a Swedish map. I talked about this briefly in my five-minute talk on Collation from SQLPASS (the one which was slightly less than serious). So by looking at the plan, I can work out what the next letter is in the alphabet of the collation used by the column. In other words, if my alphabet were Swedish, I’d be able to tell what the next letter after F is – just in case it’s not G. It turns out it is… Yes, the Swedish letter after F is G. But I worked this out by using a copy of my PhoneBook table that used the Finnish_Swedish_CI_AI collation. I couldn’t find how the Query Optimizer calculates the G, and my friend Paul White (@SQL_Kiwi) tells me that it’s frustratingly internal to the QO. He’s particularly smart, even if he is from New Zealand. To investigate further, I decided to do some PowerShell, leveraging the Get-SqlPlan function that I blogged about recently (make sure you also have the SqlServerCmdletSnapin100 snap-in added). I started by indicating that I was going to use Finnish_Swedish_CI_AI as my collation of choice, and that I’d start whichever letter cam straight after the number 9. I figure that this is a cheat’s way of guessing the first letter of the alphabet (but it doesn’t actually work in Unicode – luckily I’m using varchar not nvarchar. Actually, there are a few aspects of this code that only work using ASCII, so apologies if you were wanting to apply it to Greek, Japanese, etc). I also initialised my $alphabet variable. $collation = 'Finnish_Swedish_CI_AI'; $firstletter = '9'; $alphabet = ''; Now I created the table for my test. A single field would do, and putting a Clustered Index on it would suffice for the Seeks. Invoke-Sqlcmd -server . -data tempdb -query "create table dbo.collation_test (col varchar(10) collate $collation primary key);" Now I get into the looping. $c = $firstletter; $stillgoing = $true; while ($stillgoing) { I construct the query I want, seeking for entries which start with whatever $c has reached, and get the plan for it: $query = "select col from dbo.collation_test where col like '$($c)%';"; [xml] $pl = get-sqlplan $query "." "tempdb"; At this point, my $pl variable is a scary piece of XML, representing the execution plan. A bit of hunting through it showed me that the EndRange element contained what I was after, and that if it contained NULL, then I was done. $stillgoing = ($pl.ShowPlanXML.BatchSequence.Batch.Statements.StmtSimple.QueryPlan.RelOp.IndexScan.SeekPredicates.SeekPredicateNew.SeekKeys.EndRange -ne $null); Now I could grab the value out of it (which came with apostrophes that needed stripping), and append that to my $alphabet variable. if ($stillgoing) { $c=$pl.ShowPlanXML.BatchSequence.Batch.Statements.StmtSimple.QueryPlan.RelOp.IndexScan.SeekPredicates.SeekPredicateNew.SeekKeys.EndRange.RangeExpressions.ScalarOperator.ScalarString.Replace("'",""); $alphabet += $c; } Finally, finishing the loop, dropping the table, and showing my alphabet! } Invoke-Sqlcmd -server . -data tempdb -query "drop table dbo.collation_test;"; $alphabet; When I run all this, I see that the Swedish alphabet is ABCDEFGHIJKLMNOPQRSTUVXYZÅÄÖ, which matches what I see at Wikipedia. Interesting to see that the letters on the end are still there, even with Case Insensitivity. Turns out they’re not just “letters with accents”, they’re letters in their own right. I’m sure you gave up reading long ago, and really aren’t that fazed about the idea of doing this using PowerShell. I chose PowerShell because I’d already come up with an easy way of grabbing the estimated plan for a query, and PowerShell does allow for easy navigation of XML. I find the most interesting aspect of this as the fact that the Query Optimizer uses the next letter of the alphabet to maintain the SARGability of LIKE. I’m hoping they do something similar for a whole bunch of operations. Oh, and the fact that you know how to find stuff in the IKEA catalogue. Footnote: If you are interested in whether this works in other languages, you might want to consider the following screenshot, which shows that in principle, it should work with Japanese. It might be a bit harder to run this in PowerShell though, as I’m not sure how it translates. In Hiragana, the Japanese alphabet starts ?, ?, ?, ?, ?, ...

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Functions inside page using Razor View Engine – ASP.NET MVC

- by hajan

As we already know, Razor is probably the best view engine for ASP.NET MVC so far. It keeps your code fluid and very expressive. Besides the other functionalities Razor has, it also supports writing local functions. If you want to write a function, you can’t just open new @{ } razor block and write it there… it won’t work. Instead, you should specify @functions { } so that inside the brackets you will write your own C#/VB.NET functions/methods. Lets see an example: 1. I have the following loop that prints data using Razor <ul> @{ int N = 10; for (int i = 1; i<=N; i++) { <li>Number @i</li> } } </ul> This code will print the numbers from 1 to 10: Number 1 Number 2 Number 3 Number 4 Number 5 Number 6 Number 7 Number 8 Number 9 Number 10 So, now lets write a function that will check if current number is even, if yes… add Even before Number word. Function in Razor @functions{ public bool isEven(int number) { return number % 2 == 0 ? true : false; } } The modified code which creates unordered list is: <ul> @{ int N = 10; for (int i = 1; i<=N; i++) { if (isEven(@i)) { <li>Even number @i</li> } else { <li>Number @i</li> } } } </ul> As you can see, in the modified code we use the isEven(@i) function to check if the current number is even or not… The result is: Number 1 Even number 2 Number 3 Even number 4 Number 5 Even number 6 Number 7 Even number 8 Number 9 Even number 10 So, the main point of this blog was to show how you can define your own functions inside page using Razor View Engine. Of course you can define multiple functions inside the same @functions { } defined razor statement. The complete code: @{ Layout = null; } <!DOCTYPE html> <html> <head> <title>ASP.NET MVC - Razor View Engine :: Functions</title> </head> <body> <div> <ul> @{ int N = 10; for (int i = 1; i<=N; i++) { if (isEven(@i)) { <li>Even number @i</li> } else { <li>Number @i</li> } } } </ul> @functions{ public bool isEven(int number) { return number % 2 == 0 ? true : false; } } </div> </body> </html> Hope you like it. Regards, Hajan

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Stuck removing ffmpeg from system due to package problems

- by Michiel

I'd be very grateful to get a bit of support on the following situation: Using Ubuntu 12.04, and I used the PPA of Jon Severinson for ffmpeg. I had a problem playing movies with mplayer, so I decided to remove the PPA and try to use libav only after I read this article about libav vs ffmpeg. I first removed the PPA from the list, then apt-get update, etc. But I couldn't remove ffmpeg due to dependency-errors and got stuck in what seemed some kind of loop. Then I found a suggestion here. I followed the steps, and ended up force-removing libavcodec-extra-53. Because, apparently that was "what got stuff moving again". At the moment I can't. Now Ubuntu is reporting a broken package (BrokenCount 0). Errors: De afhankelijkheden van de volgende pakketten konden niet geïnstalleerd worden: audacious-plugins: Depends: audacious-plugins-data (= 3.2.1-4ubuntu1) maar 3.2.1-4ubuntu1 is geïnstalleerd Depends: libavcodec-extra-53 (= 4:0.8-1~) maar het is niet geïnstalleerd Depends: libavformat-extra-53 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libavutil-extra-51 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libcurl3-gnutls (= 7.16.2-1) maar 7.22.0-3ubuntu4 is geïnstalleerd Depends: libgcc1 (= 1:4.1.1) maar 1:4.6.3-1ubuntu5 is geïnstalleerd Depends: libpulse0 (= 1:0.99.1) maar 1:1.1-0ubuntu15.1 is geïnstalleerd Depends: libstdc++6 (= 4.6) maar 4.6.3-1ubuntu5 is geïnstalleerd Depends: libwavpack1 (= 4.40.0) maar 4.60.1-2 is geïnstalleerd Depends: libxcomposite1 (= 1:0.3-1) maar 1:0.4.3-2build1 is geïnstalleerd Depends: zlib1g (= 1:1.1.4) maar 1:1.2.3.4.dfsg-3ubuntu4 is geïnstalleerd libavfilter-extra-2: Depends: libavcodec-extra-53 (= 6:0.10.4.0ubuntu0jon2.2) maar het is niet geïnstalleerd Depends: libavcodec-extra-53 (< 6:0.10.4.0ubuntu0jon2.2-99) maar het is niet geïnstalleerd Depends: libavformat-extra-53 (= 6:0.10.4.0ubuntu0jon2.2) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libavutil-extra-51 (= 6:0.10.4.0ubuntu0jon2.2) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libswresample-extra-0 (= 6:0.10.4.0ubuntu0jon2.2) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libswscale-extra-2 (= 6:0.10.4.0ubuntu0jon2.2) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd libavformat-extra-53: Depends: libavcodec-extra-53 (= 6:0.10.4.0ubuntu0jon2.2) maar het is niet geïnstalleerd Depends: libavcodec-extra-53 (< 6:0.10.4.0ubuntu0jon2.2-99) maar het is niet geïnstalleerd Depends: libavutil-extra-51 (= 6:0.10.4.0ubuntu0jon2.2) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd libk3b6-extracodecs: Depends: libavcodec-extra-53 (= 4:0.8-1~) maar het is niet geïnstalleerd Depends: libavformat-extra-53 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libavutil-extra-51 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libc6 (= 2.14) maar 2.15-0ubuntu10 is geïnstalleerd Depends: libkdecore5 (= 4:4.4.4) maar 4:4.8.4a-0ubuntu0.2 is geïnstalleerd Depends: libkio5 (= 4:4.4.4) maar 4:4.8.4a-0ubuntu0.2 is geïnstalleerd Depends: libqtcore4 (= 4:4.7.0~beta1) maar 4:4.8.1-0ubuntu4.2 is geïnstalleerd Depends: libstdc++6 (= 4.1.1) maar 4.6.3-1ubuntu5 is geïnstalleerd libquicktime2: Depends: libavcodec-extra-53 (= 4:0.8~beta2-2) maar het is niet geïnstalleerd Depends: libswscale-extra-2 (= 4:0.8~beta2-2) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd libxine1-ffmpeg: Depends: libavcodec-extra-53 (= 4:0.7.3-1) maar het is niet geïnstalleerd Depends: libavutil-extra-51 (= 4:0.7.3-1) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libc6 (= 2.4) maar 2.15-0ubuntu10 is geïnstalleerd Depends: libpostproc-extra-52 (= 4:0.7.3-1) maar het is niet geïnstalleerd Depends: libxine1-bin (= 1.1.20-2build1) maar 1.1.20-2build1 is geïnstalleerd mencoder: Depends: libavcodec-extra-53 (= 4:0.8-1~) maar het is niet geïnstalleerd Depends: libavformat-extra-53 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libavutil-extra-51 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libpostproc-extra-52 (= 4:0.8-1~) maar het is niet geïnstalleerd Depends: libswscale-extra-2 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd mplayer: Depends: libavcodec-extra-53 (= 4:0.8-1~) maar het is niet geïnstalleerd Depends: libavformat-extra-53 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libavutil-extra-51 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libpostproc-extra-52 (= 4:0.8-1~) maar het is niet geïnstalleerd Depends: libswscale-extra-2 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd vlc: Depends: vlc-nox (= 2.0.3-0ubuntu0.12.04.1) maar 2.0.3-0ubuntu0.12.04.1 is geïnstalleerd Depends: libavcodec-extra-53 (= 4:0.8-1~) maar het is niet geïnstalleerd Depends: libavutil-extra-51 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libc6 (= 2.15) maar 2.15-0ubuntu10 is geïnstalleerd Depends: libfreetype6 (= 2.2.1) maar 2.4.8-1ubuntu2 is geïnstalleerd Depends: libgcc1 (= 1:4.1.1) maar 1:4.6.3-1ubuntu5 is geïnstalleerd Depends: libqtcore4 (= 4:4.8.0) maar 4:4.8.1-0ubuntu4.2 is geïnstalleerd Depends: libqtgui4 (= 4:4.7.0~beta1) maar 4:4.8.1-0ubuntu4.2 is geïnstalleerd Depends: libstdc++6 (= 4.6) maar 4.6.3-1ubuntu5 is geïnstalleerd Depends: zlib1g (= 1:1.2.3.3.dfsg) maar 1:1.2.3.4.dfsg-3ubuntu4 is geïnstalleerd vlc-nox: Depends: libavcodec-extra-53 (= 4:0.8-1~) maar het is niet geïnstalleerd Depends: libavformat-extra-53 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libavutil-extra-51 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libc6 (= 2.15) maar 2.15-0ubuntu10 is geïnstalleerd Depends: libfontconfig1 (= 2.8.0) maar 2.8.0-3ubuntu9.1 is geïnstalleerd Depends: libfreetype6 (= 2.2.1) maar 2.4.8-1ubuntu2 is geïnstalleerd Depends: libgcc1 (= 1:4.1.1) maar 1:4.6.3-1ubuntu5 is geïnstalleerd Depends: libgnutls26 (= 2.12.6.1-0) maar 2.12.14-5ubuntu3.1 is geïnstalleerd Depends: libmpcdec6 (= 1:0.1~r435) maar 2:0.1~r459-1ubuntu1 is geïnstalleerd Depends: libncursesw5 (= 5.6+20070908) maar 5.9-4 is geïnstalleerd Depends: libpostproc-extra-52 (= 4:0.8-1~) maar het is niet geïnstalleerd Depends: libsmbclient (= 3.0.24) maar 2:3.6.3-2ubuntu2.3 is geïnstalleerd Depends: libstdc++6 (= 4.6) maar 4.6.3-1ubuntu5 is geïnstalleerd Depends: libswscale-extra-2 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libudev0 (= 147) maar 175-0ubuntu9.1 is geïnstalleerd Depends: libxml2 (= 2.7.4) maar 2.7.8.dfsg-5.1ubuntu4.1 is geïnstalleerd Depends: zlib1g (= 1:1.2.0.2) maar 1:1.2.3.4.dfsg-3ubuntu4 is geïnstalleerd xbmc-bin: Depends: libavcodec-extra-53 (= 4:0.8-1~) maar het is niet geïnstalleerd Depends: libavfilter-extra-2 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libavformat-extra-53 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libavutil-extra-51 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd Depends: libpostproc-extra-52 (= 4:0.8-1~) maar het is niet geïnstalleerd Depends: libswscale-extra-2 (= 4:0.8-1~) maar 6:0.10.4.0ubuntu0jon2.2 is geïnstalleerd And apt-get is reporting: root@LAPTOP:~# apt-get -f install Pakketlijsten worden ingelezen... Klaar Boom van vereisten wordt opgebouwd De status informatie wordt gelezen... Klaar Vereisten worden gecorrigeerd... mislukt. De volgende pakketten hebben niet-voldane vereisten: audacious-plugins : Vereisten: libavcodec53 (= 4:0.8-1~) maar het is niet geïnstalleerd of libavcodec-extra-53 (= 4:0.8-1~) maar het is niet geïnstalleerd libavfilter-extra-2 : Vereisten: libavcodec-extra-53 (= 6:0.10.4.0ubuntu0jon2.2) maar het is niet geïnstalleerd Vereisten: libavcodec-extra-53 (< 6:0.10.4.0ubuntu0jon2.2-99) maar het is niet geïnstalleerd libavformat-extra-53 : Vereisten: libavcodec-extra-53 (= 6:0.10.4.0ubuntu0jon2.2) maar het is niet geïnstalleerd Vereisten: libavcodec-extra-53 (< 6:0.10.4.0ubuntu0jon2.2-99) maar het is niet geïnstalleerd libk3b6-extracodecs : Vereisten: libavcodec53 (= 4:0.8-1~) maar het is niet geïnstalleerd of libavcodec-extra-53 (= 4:0.8-1~) maar het is niet geïnstalleerd libquicktime2 : Vereisten: libavcodec53 (= 4:0.8~beta2-2) maar het is niet geïnstalleerd of libavcodec-extra-53 (= 4:0.8~beta2-2) maar het is niet geïnstalleerd libxine1-ffmpeg : Vereisten: libavcodec53 (= 4:0.7.3-1) maar het is niet geïnstalleerd of libavcodec-extra-53 (= 4:0.7.3-1) maar het is niet geïnstalleerd mencoder : Vereisten: libavcodec53 (= 4:0.8-1~) maar het is niet geïnstalleerd of libavcodec-extra-53 (= 4:0.8-1~) maar het is niet geïnstalleerd mplayer : Vereisten: libavcodec53 (= 4:0.8-1~) maar het is niet geïnstalleerd of libavcodec-extra-53 (= 4:0.8-1~) maar het is niet geïnstalleerd vlc : Vereisten: libavcodec53 (= 4:0.8-1~) maar het is niet geïnstalleerd of libavcodec-extra-53 (= 4:0.8-1~) maar het is niet geïnstalleerd vlc-nox : Vereisten: libavcodec53 (= 4:0.8-1~) maar het is niet geïnstalleerd of libavcodec-extra-53 (= 4:0.8-1~) maar het is niet geïnstalleerd xbmc-bin : Vereisten: libavcodec53 (= 4:0.8-1~) maar het is niet geïnstalleerd of libavcodec-extra-53 (= 4:0.8-1~) maar het is niet geïnstalleerd E: Fout, pkgProblemResolver::Resolve maakte scheidingen aan, dit kan veroorzaakt worden door vastgehouden pakketten. E: Kan vereisten niet corrigeren How to proceed?? Thanks in advance, Michiel

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Lessons from rewriting POP Forums for MVC, open source-like

- by Jeff

It has been a ton of work, interrupted over the last two years by unemployment, moving, a baby, failing to sell houses and other life events, but it's really exciting to see POP Forums v9 coming together. I'm not even sure when I decided to really commit to it as an open source project, but working on the same team as the CodePlex folks probably had something to do with it. Moving along the roadmap I set for myself, the app is now running on a quasi-production site... we launched MouseZoom last weekend. (That's a post-beta 1 build of the forum. There's also some nifty Silverlight DeepZoom goodness on that site.)I have to make a point to illustrate just how important starting over was for me. I started this forum thing for my sites in old ASP more than ten years ago. What a mess that stuff was, including SQL injection vulnerabilities and all kinds of crap. It went to ASP.NET in 2002, but even then, it felt a little too much like script. More than a year later, in 2003, I did an honest to goodness rewrite. If you've been in this business of writing code for any amount of time, you know how much you hate what you wrote a month ago, so just imagine that with seven years in between. The subsequent versions still carried a fair amount of crap, and that's why I had to start over, to make a clean break. Mind you, much of that crap is still running on some of my production sites in a stable manner, but it's a pain in the ass to maintain.So with that clean break, there is much that I have learned. These are a few of those lessons, in no particular order...Avoid shiny object syndromeOver the years, I've embraced new things without bothering to ask myself why. I remember spending the better part of a year trying to adapt this app to use the membership and profile API's in ASP.NET, just because they were there. They didn't solve any known problem. Early on in this version, I dabbled in exotic ORM's, even though I already had the fundamental SQL that I knew worked. I bloated up the client side code with all kinds of jQuery UI and plugins just because, and it got in the way. All the new shiny can be distracting, and I've come to realize that I've allowed it to be a distraction most of my professional life.Just query what you needI've spent a lot of time over-thinking how to query data. In the SQL world, this means exotic joins, special caches, the read-update-commit loop of ORM's, etc. There are times when you have to remind yourself that you aren't Facebook, you'll never be Facebook, and that databases are in fact intended to serve data. In a lot of projects, back in the day, I used to have these big, rich data objects and pass them all over the place, through various application tiers, when in reality, all I needed was some ID from the entity. I try to be mindful of how many queries hit the database on a given request, but I don't obsess over it. I just get what I need.Don't spend too much time worrying about your unit testsIf you've looked at any of the tests for POP Forums, you might offer an audible WTF. That's OK. There's a whole lot of mocking going on. In some cases, it points out where you're doing too much, and that's good for improving your design. In other cases it shows where your design sucks. But the biggest trap of unit testing is that you worry it should be prettier. That's a waste of time. When you write a test, in many cases before the production code, the important part is that you're testing the right thing. If you have to mock up a bunch of stuff to test the outcome, so be it, but it's not wasted time. You're still doing up the typical arrange-action-assert deal, and you'll be able to read that later if you need to.Get back to your HTTP rootsASP.NET Webforms did a reasonably decent job at abstracting us away from the stateless nature of the Web. A lot of people criticize it, but I think it all worked pretty well. These days, with MVC, jQuery, REST services, and what not, we've gone back to thinking about the wire. The nuts and bolts passing between our Web browser and server matters. This doesn't make things harder, in my opinion, it makes them easier. There is something incredibly freeing about how we approach development of Web apps now. HTTP is a really simple protocol, and the stuff we push through it, in particular HTML and JSON, are pretty simple too. The debugging points are really easy to trap and trace.Premature optimization is prematureI'll go back to the data thing for a moment. I've been known to look at a particular action or use case and stress about the number of calls that are made to the database. I'm not suggesting that it's a bad thing to keep these in mind, but if you worry about it outside of the context of the actual impact, you're wasting time. For example, I query the database for last read times in a forum separately of the user and the list of forums. The impact on performance barely exists. If I put it under load, exceeding the kind of load I expect, it still barely has an impact. Then consider it only counts for logged in users. The context of this "inefficient" action is that it doesn't matter. Did I mention I won't be Facebook?Solve your own problems firstThis is another trap I've fallen into. I've often thought about what other people might need for some feature or aspect of the app. In other words, I was willing to make design decisions based on non-existent data. How stupid is that? When I decided to truly open source this thing, building for myself first was a stated design goal. This app has to server the audiences of CoasterBuzz, MouseZoom and other sites first. In this development scenario, you don't have access to mountains of usability studies or user focus groups. You have to start with what you know.I'm sure there are other points I could make too. It has been a lot of fun to work on, and I look forward to evolving the UI as time goes on. That's where I hope to see more magic in the future.

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XNA: Rotating Bones

- by MLM

XNA 4.0 I am trying to learn how to rotate bones on a very simple tank model I made in Cinema 4D. It is rigged by 3 bones, Root - Main - Turret - Barrel I have binded all of the objects to the bones so that all translations/rotations work as planned in C4D. I exported it as .fbx I based my test project after: http://create.msdn.com/en-US/education/catalog/sample/simple_animation I can build successfully with no errors but all the rotations I try to do to my bones have no effect. I can transform my Root successfully using below but the bone transforms have no effect: myModel.Root.Transform = world; Matrix turretRotation = Matrix.CreateRotationY(MathHelper.ToRadians(37)); Matrix barrelRotation = Matrix.CreateRotationX(barrelRotationValue); MainBone.Transform = MainTransform; TurretBone.Transform = turretRotation * TurretTransform; BarrelBone.Transform = barrelRotation * BarrelTransform; I am wondering if my model is just not right or something important I am missing in the code. Here is my Game1.cs using System; using System.Collections.Generic; using System.Linq; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Media; namespace ModelTesting { /// <summary> /// This is the main type for your game /// </summary> public class Game1 : Microsoft.Xna.Framework.Game { GraphicsDeviceManager graphics; SpriteBatch spriteBatch; float aspectRatio; Tank myModel; public Game1() { graphics = new GraphicsDeviceManager(this); Content.RootDirectory = "Content"; } /// <summary> /// Allows the game to perform any initialization it needs to before starting to run. /// This is where it can query for any required services and load any non-graphic /// related content. Calling base.Initialize will enumerate through any components /// and initialize them as well. /// </summary> protected override void Initialize() { // TODO: Add your initialization logic here myModel = new Tank(); base.Initialize(); } /// <summary> /// LoadContent will be called once per game and is the place to load /// all of your content. /// </summary> protected override void LoadContent() { // Create a new SpriteBatch, which can be used to draw textures. spriteBatch = new SpriteBatch(GraphicsDevice); // TODO: use this.Content to load your game content here myModel.Load(Content); aspectRatio = graphics.GraphicsDevice.Viewport.AspectRatio; } /// <summary> /// UnloadContent will be called once per game and is the place to unload /// all content. /// </summary> protected override void UnloadContent() { // TODO: Unload any non ContentManager content here } /// <summary> /// Allows the game to run logic such as updating the world, /// checking for collisions, gathering input, and playing audio. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Update(GameTime gameTime) { // Allows the game to exit if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed) this.Exit(); // TODO: Add your update logic here float time = (float)gameTime.TotalGameTime.TotalSeconds; // Move the pieces /* myModel.TurretRotation = (float)Math.Sin(time * 0.333f) * 1.25f; myModel.BarrelRotation = (float)Math.Sin(time * 0.25f) * 0.333f - 0.333f; */ base.Update(gameTime); } /// <summary> /// This is called when the game should draw itself. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); // Calculate the camera matrices. float time = (float)gameTime.TotalGameTime.TotalSeconds; Matrix rotation = Matrix.CreateRotationY(MathHelper.ToRadians(45)); Matrix view = Matrix.CreateLookAt(new Vector3(2000, 500, 0), new Vector3(0, 150, 0), Vector3.Up); Matrix projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.PiOver4, graphics.GraphicsDevice.Viewport.AspectRatio, 10, 10000); // TODO: Add your drawing code here myModel.Draw(rotation, view, projection); base.Draw(gameTime); } } } And here is my tank class: using System; using System.Collections.Generic; using System.Linq; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Media; namespace ModelTesting { public class Tank { Model myModel; // Array holding all the bone transform matrices for the entire model. // We could just allocate this locally inside the Draw method, but it // is more efficient to reuse a single array, as this avoids creating // unnecessary garbage. public Matrix[] boneTransforms; // Shortcut references to the bones that we are going to animate. // We could just look these up inside the Draw method, but it is more // efficient to do the lookups while loading and cache the results. ModelBone MainBone; ModelBone TurretBone; ModelBone BarrelBone; // Store the original transform matrix for each animating bone. Matrix MainTransform; Matrix TurretTransform; Matrix BarrelTransform; // current animation positions float turretRotationValue; float barrelRotationValue; /// <summary> /// Gets or sets the turret rotation amount. /// </summary> public float TurretRotation { get { return turretRotationValue; } set { turretRotationValue = value; } } /// <summary> /// Gets or sets the barrel rotation amount. /// </summary> public float BarrelRotation { get { return barrelRotationValue; } set { barrelRotationValue = value; } } /// <summary> /// Load the model /// </summary> public void Load(ContentManager Content) { // TODO: use this.Content to load your game content here myModel = Content.Load<Model>("Models\\simple_tank02"); MainBone = myModel.Bones["Main"]; TurretBone = myModel.Bones["Turret"]; BarrelBone = myModel.Bones["Barrel"]; MainTransform = MainBone.Transform; TurretTransform = TurretBone.Transform; BarrelTransform = BarrelBone.Transform; // Allocate the transform matrix array. boneTransforms = new Matrix[myModel.Bones.Count]; } public void Draw(Matrix world, Matrix view, Matrix projection) { myModel.Root.Transform = world; Matrix turretRotation = Matrix.CreateRotationY(MathHelper.ToRadians(37)); Matrix barrelRotation = Matrix.CreateRotationX(barrelRotationValue); MainBone.Transform = MainTransform; TurretBone.Transform = turretRotation * TurretTransform; BarrelBone.Transform = barrelRotation * BarrelTransform; myModel.CopyAbsoluteBoneTransformsTo(boneTransforms); // Draw the model, a model can have multiple meshes, so loop foreach (ModelMesh mesh in myModel.Meshes) { // This is where the mesh orientation is set foreach (BasicEffect effect in mesh.Effects) { effect.World = boneTransforms[mesh.ParentBone.Index]; effect.View = view; effect.Projection = projection; effect.EnableDefaultLighting(); } // Draw the mesh, will use the effects set above mesh.Draw(); } } } }

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Movement prediction for non-shooters

- by ShadowChaser

I'm working on an isometric 2D game with moderate-scale multiplayer, approximately 20-30 players connected at once to a persistent server. I've had some difficulty getting a good movement prediction implementation in place. Physics/Movement The game doesn't have a true physics implementation, but uses the basic principles to implement movement. Rather than continually polling input, state changes (ie/ mouse down/up/move events) are used to change the state of the character entity the player is controlling. The player's direction (ie/ north-east) is combined with a constant speed and turned into a true 3D vector - the entity's velocity. In the main game loop, "Update" is called before "Draw". The update logic triggers a "physics update task" that tracks all entities with a non-zero velocity uses very basic integration to change the entities position. For example: entity.Position += entity.Velocity.Scale(ElapsedTime.Seconds) (where "Seconds" is a floating point value, but the same approach would work for millisecond integer values). The key point is that no interpolation is used for movement - the rudimentary physics engine has no concept of a "previous state" or "current state", only a position and velocity. State Change and Update Packets When the velocity of the character entity the player is controlling changes, a "move avatar" packet is sent to the server containing the entity's action type (stand, walk, run), direction (north-east), and current position. This is different from how 3D first person games work. In a 3D game the velocity (direction) can change frame to frame as the player moves around. Sending every state change would effectively transmit a packet per frame, which would be too expensive. Instead, 3D games seem to ignore state changes and send "state update" packets on a fixed interval - say, every 80-150ms. Since speed and direction updates occur much less frequently in my game, I can get away with sending every state change. Although all of the physics simulations occur at the same speed and are deterministic, latency is still an issue. For that reason, I send out routine position update packets (similar to a 3D game) but much less frequently - right now every 250ms, but I suspect with good prediction I can easily boost it towards 500ms. The biggest problem is that I've now deviated from the norm - all other documentation, guides, and samples online send routine updates and interpolate between the two states. It seems incompatible with my architecture, and I need to come up with a better movement prediction algorithm that is closer to a (very basic) "networked physics" architecture. The server then receives the packet and determines the players speed from it's movement type based on a script (Is the player able to run? Get the player's running speed). Once it has the speed, it combines it with the direction to get a vector - the entity's velocity. Some cheat detection and basic validation occurs, and the entity on the server side is updated with the current velocity, direction, and position. Basic throttling is also performed to prevent players from flooding the server with movement requests. After updating its own entity, the server broadcasts an "avatar position update" packet to all other players within range. The position update packet is used to update the client side physics simulations (world state) of the remote clients and perform prediction and lag compensation. Prediction and Lag Compensation As mentioned above, clients are authoritative for their own position. Except in cases of cheating or anomalies, the client's avatar will never be repositioned by the server. No extrapolation ("move now and correct later") is required for the client's avatar - what the player sees is correct. However, some sort of extrapolation or interpolation is required for all remote entities that are moving. Some sort of prediction and/or lag-compensation is clearly required within the client's local simulation / physics engine. Problems I've been struggling with various algorithms, and have a number of questions and problems: Should I be extrapolating, interpolating, or both? My "gut feeling" is that I should be using pure extrapolation based on velocity. State change is received by the client, client computes a "predicted" velocity that compensates for lag, and the regular physics system does the rest. However, it feels at odds to all other sample code and articles - they all seem to store a number of states and perform interpolation without a physics engine. When a packet arrives, I've tried interpolating the packet's position with the packet's velocity over a fixed time period (say, 200ms). I then take the difference between the interpolated position and the current "error" position to compute a new vector and place that on the entity instead of the velocity that was sent. However, the assumption is that another packet will arrive in that time interval, and it's incredibly difficult to "guess" when the next packet will arrive - especially since they don't all arrive on fixed intervals (ie/ state changes as well). Is the concept fundamentally flawed, or is it correct but needs some fixes / adjustments? What happens when a remote player stops? I can immediately stop the entity, but it will be positioned in the "wrong" spot until it moves again. If I estimate a vector or try to interpolate, I have an issue because I don't store the previous state - the physics engine has no way to say "you need to stop after you reach position X". It simply understands a velocity, nothing more complex. I'm reluctant to add the "packet movement state" information to the entities or physics engine, since it violates basic design principles and bleeds network code across the rest of the game engine. What should happen when entities collide? There are three scenarios - the controlling player collides locally, two entities collide on the server during a position update, or a remote entity update collides on the local client. In all cases I'm uncertain how to handle the collision - aside from cheating, both states are "correct" but at different time periods. In the case of a remote entity it doesn't make sense to draw it walking through a wall, so I perform collision detection on the local client and cause it to "stop". Based on point #2 above, I might compute a "corrected vector" that continually tries to move the entity "through the wall" which will never succeed - the remote avatar is stuck there until the error gets too high and it "snaps" into position. How do games work around this?

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How to use Azure storage for uploading and displaying pictures.

- by Magnus Karlsson

Basic set up of Azure storage for local development and production. This is a somewhat completion of the following guide from http://www.windowsazure.com/en-us/develop/net/how-to-guides/blob-storage/ that also involves a practical example that I believe is commonly used, i.e. upload and present an image from a user. First we set up for local storage and then we configure for them to work on a web role. Steps: 1. Configure connection string locally. 2. Configure model, controllers and razor views. 1. Setup connectionsstring 1.1 Right click your web role and choose “Properties”. 1.2 Click Settings. 1.3 Add setting. 1.4 Name your setting. This will be the name of the connectionstring. 1.5 Click the ellipsis to the right. (the ellipsis appear when you mark the area. 1.6 The following window appears- Select “Windows Azure storage emulator” and click ok. Now we have a connection string to use. To be able to use it we need to make sure we have windows azure tools for storage. 2.1 Click Tools –> Library Package manager –> Manage Nuget packages for solution. 2.2 This is what it looks like after it has been added. Now on to what the code should look like. 3.1 First we need a view which collects images to upload. Here Index.cshtml. 1: @model List<string> 2: 3: @{ 4: ViewBag.Title = "Index"; 5: } 6: 7: <h2>Index</h2> 8: <form action="@Url.Action("Upload")" method="post" enctype="multipart/form-data"> 9: 10: <label for="file">Filename:</label> 11: <input type="file" name="file" id="file1" /> 12: <br /> 13: <label for="file">Filename:</label> 14: <input type="file" name="file" id="file2" /> 15: <br /> 16: <label for="file">Filename:</label> 17: <input type="file" name="file" id="file3" /> 18: <br /> 19: <label for="file">Filename:</label> 20: <input type="file" name="file" id="file4" /> 21: <br /> 22: <input type="submit" value="Submit" /> 23: 24: </form> 25: 26: @foreach (var item in Model) { 27: 28: <img src="@item" alt="Alternate text"/> 29: } 3.2 We need a controller to receive the post. Notice the “containername” string I send to the blobhandler. I use this as a folder for the pictures for each user. If this is not a requirement you could just call it container or anything with small characters directly when creating the container. 1: public ActionResult Upload(IEnumerable<HttpPostedFileBase> file) 2: { 3: BlobHandler bh = new BlobHandler("containername"); 4: bh.Upload(file); 5: var blobUris=bh.GetBlobs(); 6: 7: return RedirectToAction("Index",blobUris); 8: } 3.3 The handler model. I’ll let the comments speak for themselves. 1: public class BlobHandler 2: { 3: // Retrieve storage account from connection string. 4: CloudStorageAccount storageAccount = CloudStorageAccount.Parse( 5: CloudConfigurationManager.GetSetting("StorageConnectionString")); 6: 7: private string imageDirecoryUrl; 8: 9: /// <summary> 10: /// Receives the users Id for where the pictures are and creates 11: /// a blob storage with that name if it does not exist. 12: /// </summary> 13: /// <param name="imageDirecoryUrl"></param> 14: public BlobHandler(string imageDirecoryUrl) 15: { 16: this.imageDirecoryUrl = imageDirecoryUrl; 17: // Create the blob client. 18: CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient(); 19: 20: // Retrieve a reference to a container. 21: CloudBlobContainer container = blobClient.GetContainerReference(imageDirecoryUrl); 22: 23: // Create the container if it doesn't already exist. 24: container.CreateIfNotExists(); 25: 26: //Make available to everyone 27: container.SetPermissions( 28: new BlobContainerPermissions 29: { 30: PublicAccess = BlobContainerPublicAccessType.Blob 31: }); 32: } 33: 34: public void Upload(IEnumerable<HttpPostedFileBase> file) 35: { 36: // Create the blob client. 37: CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient(); 38: 39: // Retrieve a reference to a container. 40: CloudBlobContainer container = blobClient.GetContainerReference(imageDirecoryUrl); 41: 42: if (file != null) 43: { 44: foreach (var f in file) 45: { 46: if (f != null) 47: { 48: CloudBlockBlob blockBlob = container.GetBlockBlobReference(f.FileName); 49: blockBlob.UploadFromStream(f.InputStream); 50: } 51: } 52: } 53: } 54: 55: public List<string> GetBlobs() 56: { 57: // Create the blob client. 58: CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient(); 59: 60: // Retrieve reference to a previously created container. 61: CloudBlobContainer container = blobClient.GetContainerReference(imageDirecoryUrl); 62: 63: List<string> blobs = new List<string>(); 64: 65: // Loop over blobs within the container and output the URI to each of them 66: foreach (var blobItem in container.ListBlobs()) 67: blobs.Add(blobItem.Uri.ToString()); 68: 69: return blobs; 70: } 71: } 3.4 So, when the files have been uploaded we will get them to present them to out user in the index page. Pretty straight forward. In this example we only present the image by sending the Uri’s to the view. A better way would be to save them up in a view model containing URI, metadata, alternate text, and other relevant information but for this example this is all we need. 4. Now press F5 in your solution to try it out. You can see the storage emulator UI here: 4.1 If you get any exceptions or errors I suggest to first check if the service Is running correctly. I had problem with this and they seemed related to the installation and a reboot fixed my problems. 5. Set up for Cloud storage. To do this we need to add configuration for cloud just as we did for local in step one. 5.1 We need our keys to do this. Go to the windows Azure menagement portal, select storage icon to the right and click “Manage keys”. (Image from a different blog post though). 5.2 Do as in step 1.but replace step 1.6 with: 1.6 Choose “Manually entered credentials”. Enter your account name. 1.7 Paste your Account Key from step 5.1. and click ok. 5.3. Save, publish and run! Please feel free to ask any questions using the comments form at the bottom of this page. I will get back to you to help you solve any questions. Our consultancy agency also provides services in the Nordic regions if you would like any further support.

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Sliding collision response

- by dbostream

I have been reading plenty of tutorials about sliding collision responses yet I am not able to implement it properly in my project. What I want to do is make a puck slide along the rounded corner boards of a hockey rink. In my latest attempt the puck does slide along the boards but there are some strange velocity behaviors. First of all the puck slows down a lot pretty much right away and then it slides for awhile and stops before exiting the corner. Even if I double the speed I get a similar behavior and the puck does not make it out of the corner. I used some ideas from this document http://www.peroxide.dk/papers/collision/collision.pdf. This is what I have: Update method called from the game loop when it is time to update the puck (I removed some irrelevant parts). I use two states (current, previous) which are used to interpolate the position during rendering. public override void Update(double fixedTimeStep) { /* Acceleration is set to 0 for now. */ Acceleration.Zero(); PreviousState = CurrentState; _collisionRecursionDepth = 0; CurrentState.Position = SlidingCollision(CurrentState.Position, CurrentState.Velocity * fixedTimeStep + 0.5 * Acceleration * fixedTimeStep * fixedTimeStep); /* Should not this be affected by a sliding collision? and not only the position. */ CurrentState.Velocity = CurrentState.Velocity + Acceleration * fixedTimeStep; Heading = Vector2.NormalizeRet(CurrentState.Velocity); } private Vector2 SlidingCollision(Vector2 position, Vector2 velocity) { if(_collisionRecursionDepth > 5) return position; bool collisionFound = false; Vector2 futurePosition = position + velocity; Vector2 intersectionPoint = new Vector2(); Vector2 intersectionPointNormal = new Vector2(); /* I did not include the collision detection code, if a collision is detected the intersection point and normal in that point is returned. */ if(!collisionFound) return futurePosition; /* If no collision was detected it is safe to move to the future position. */ /* It is not exactly the intersection point, but slightly before. */ Vector2 newPosition = intersectionPoint; /* oldVelocity is set to the distance from the newPosition(intersection point) to the position it had moved to had it not collided. */ Vector2 oldVelocity = futurePosition - newPosition; /* Project the distance left to move along the intersection normal. */ Vector2 newVelocity = oldVelocity - intersectionPointNormal * oldVelocity.DotProduct(intersectionPointNormal); if(newVelocity.LengthSq() < 0.001) return newPosition; /* If almost no speed, no need to continue. */ _collisionRecursionDepth++; return SlidingCollision(newPosition, newVelocity); } What am I doing wrong with the velocity? I have been staring at this for very long so I have gone blind. I have tried different values of recursion depth but it does not seem to make it better. Let me know if you need more information. I appreciate any help. EDIT: A combination of Patrick Hughes' and teodron's answers solved the velocity problem (I think), thanks a lot! This is the new code: I decided to use a separate recursion method now too since I don't want to recalculate the acceleration in each recursion. public override void Update(double fixedTimeStep) { Acceleration.Zero();// = CalculateAcceleration(fixedTimeStep); PreviousState = new MovingEntityState(CurrentState.Position, CurrentState.Velocity); CurrentState = SlidingCollision(CurrentState, fixedTimeStep); Heading = Vector2.NormalizeRet(CurrentState.Velocity); } private MovingEntityState SlidingCollision(MovingEntityState state, double timeStep) { bool collisionFound = false; /* Calculate the next position given no detected collision. */ Vector2 futurePosition = state.Position + state.Velocity * timeStep; Vector2 intersectionPoint = new Vector2(); Vector2 intersectionPointNormal = new Vector2(); /* I did not include the collision detection code, if a collision is detected the intersection point and normal in that point is returned. */ /* If no collision was detected it is safe to move to the future position. */ if (!collisionFound) return new MovingEntityState(futurePosition, state.Velocity); /* Set new position to the intersection point (slightly before). */ Vector2 newPosition = intersectionPoint; /* Project the new velocity along the intersection normal. */ Vector2 newVelocity = state.Velocity - 1.90 * intersectionPointNormal * state.Velocity.DotProduct(intersectionPointNormal); /* Calculate the time of collision. */ double timeOfCollision = Math.Sqrt((newPosition - state.Position).LengthSq() / (futurePosition - state.Position).LengthSq()); /* Calculate new time step, remaining time of full step after the collision * current time step. */ double newTimeStep = timeStep * (1 - timeOfCollision); return SlidingCollision(new MovingEntityState(newPosition, newVelocity), newTimeStep); } Even though the code above seems to slide the puck correctly please have a look at it. I have a few questions, if I don't multiply by 1.90 in the newVelocity calculation it doesn't work (I get a stack overflow when the puck enters the corner because the timeStep decreases very slowly - a collision is found early in every recursion), why is that? what does 1.90 really do and why 1.90? Also I have a new problem, the puck does not move parallell to the short side after exiting the curve; to be more exact it moves outside the rink (I am not checking for any collisions with the short side at the moment). When I perform the collision detection I first check that the puck is in the correct quadrant. For example bottom-right corner is quadrant four i.e. circleCenter.X < puck.X && circleCenter.Y puck.Y is this a problem? or should the short side of the rink be the one to make the puck go parallell to it and not the last collision in the corner? EDIT2: This is the code I use for collision detection, maybe it has something to do with the fact that I can't make the puck slide (-1.0) but only reflect (-2.0): /* Point is the current position (not the predicted one) and quadrant is 4 for the bottom-right corner for example. */ if (GeometryHelper.PointInCircleQuadrant(circleCenter, circleRadius, state.Position, quadrant)) { /* The line is: from = state.Position, to = futurePosition. So a collision is detected when from is inside the circle and to is outside. */ if (GeometryHelper.LineCircleIntersection2d(state.Position, futurePosition, circleCenter, circleRadius, intersectionPoint, quadrant)) { collisionFound = true; /* Set the intersection point to slightly before the real intersection point (I read somewhere this was good to do because of floting point precision, not sure exactly how much though). */ intersectionPoint = intersectionPoint - Vector2.NormalizeRet(state.Velocity) * 0.001; /* Normal at the intersection point. */ intersectionPointNormal = Vector2.NormalizeRet(circleCenter - intersectionPoint) } } When I set the intersection point, if I for example use 0.1 instead of 0.001 the puck travels further before it gets stuck, but for all values I have tried (including 0 - the real intersection point) it gets stuck somewhere (but I necessarily not get a stack overflow). Can something in this part be the cause of my problem? I can see why I get the stack overflow when using -1.0 when calculating the new velocity vector; but not how to solve it. I traced the time steps used in the recursion (initial time step is always 1/60 ~ 0.01666): Recursion depth Time step next recursive call [Start recursion, time step ~ 0.016666] 0 0,000985806527246773 [No collision, stop recursion] [Start recursion, time step ~ 0.016666] 0 0,0149596704364629 1 0,0144883449376379 2 0,0143155612984837 3 0,014224925727213 4 0,0141673917461608 5 0,0141265435314026 6 0,0140953966184117 7 0,0140704653746625 ...and so on. As you can see the collision is detected early in every recursive call which means the next time step decreases very slowly thus the recursion depth gets very big - stack overflow.

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Premature-Optimization and Performance Anxiety

- by James Michael Hare

While writing my post analyzing the new .NET 4 ConcurrentDictionary class (here), I fell into one of the classic blunders that I myself always love to warn about. After analyzing the differences of time between a Dictionary with locking versus the new ConcurrentDictionary class, I noted that the ConcurrentDictionary was faster with read-heavy multi-threaded operations. Then, I made the classic blunder of thinking that because the original Dictionary with locking was faster for those write-heavy uses, it was the best choice for those types of tasks. In short, I fell into the premature-optimization anti-pattern. Basically, the premature-optimization anti-pattern is when a developer is coding very early for a perceived (whether rightly-or-wrongly) performance gain and sacrificing good design and maintainability in the process. At best, the performance gains are usually negligible and at worst, can either negatively impact performance, or can degrade maintainability so much that time to market suffers or the code becomes very fragile due to the complexity. Keep in mind the distinction above. I'm not talking about valid performance decisions. There are decisions one should make when designing and writing an application that are valid performance decisions. Examples of this are knowing the best data structures for a given situation (Dictionary versus List, for example) and choosing performance algorithms (linear search vs. binary search). But these in my mind are macro optimizations. The error is not in deciding to use a better data structure or algorithm, the anti-pattern as stated above is when you attempt to over-optimize early on in such a way that it sacrifices maintainability. In my case, I was actually considering trading the safety and maintainability gains of the ConcurrentDictionary (no locking required) for a slight performance gain by using the Dictionary with locking. This would have been a mistake as I would be trading maintainability (ConcurrentDictionary requires no locking which helps readability) and safety (ConcurrentDictionary is safe for iteration even while being modified and you don't risk the developer locking incorrectly) -- and I fell for it even when I knew to watch out for it. I think in my case, and it may be true for others as well, a large part of it was due to the time I was trained as a developer. I began college in in the 90s when C and C++ was king and hardware speed and memory were still relatively priceless commodities and not to be squandered. In those days, using a long instead of a short could waste precious resources, and as such, we were taught to try to minimize space and favor performance. This is why in many cases such early code-bases were very hard to maintain. I don't know how many times I heard back then to avoid too many function calls because of the overhead -- and in fact just last year I heard a new hire in the company where I work declare that she didn't want to refactor a long method because of function call overhead. Now back then, that may have been a valid concern, but with today's modern hardware even if you're calling a trivial method in an extremely tight loop (which chances are the JIT compiler would optimize anyway) the results of removing method calls to speed up performance are negligible for the great majority of applications. Now, obviously, there are those coding applications where speed is absolutely king (for example drivers, computer games, operating systems) where such sacrifices may be made. But I would strongly advice against such optimization because of it's cost. Many folks that are performing an optimization think it's always a win-win. That they're simply adding speed to the application, what could possibly be wrong with that? What they don't realize is the cost of their choice. For every piece of straight-forward code that you obfuscate with performance enhancements, you risk the introduction of bugs in the long term technical debt of the application. It will become so fragile over time that maintenance will become a nightmare. I've seen such applications in places I have worked. There are times I've seen applications where the designer was so obsessed with performance that they even designed their own memory management system for their application to try to squeeze out every ounce of performance. Unfortunately, the application stability often suffers as a result and it is very difficult for anyone other than the original designer to maintain. I've even seen this recently where I heard a C++ developer bemoaning that in VS2010 the iterators are about twice as slow as they used to be because Microsoft added range checking (probably as part of the 0x standard implementation). To me this was almost a joke. Twice as slow sounds bad, but it almost never as bad as you think -- especially if you're gaining safety. The only time twice is really that much slower is when once was too slow to begin with. Think about it. 2 minutes is slow as a response time because 1 minute is slow. But if an iterator takes 1 microsecond to move one position and a new, safer iterator takes 2 microseconds, this is trivial! The only way you'd ever really notice this would be in iterating a collection just for the sake of iterating (i.e. no other operations). To my mind, the added safety makes the extra time worth it. Always favor safety and maintainability when you can. I know it can be a hard habit to break, especially if you started out your career early or in a language such as C where they are very performance conscious. But in reality, these type of micro-optimizations only end up hurting you in the long run. Remember the two laws of optimization. I'm not sure where I first heard these, but they are so true: For beginners: Do not optimize. For experts: Do not optimize yet. This is so true. If you're a beginner, resist the urge to optimize at all costs. And if you are an expert, delay that decision. As long as you have chosen the right data structures and algorithms for your task, your performance will probably be more than sufficient. Chances are it will be network, database, or disk hits that will be your slow-down, not your code. As they say, 98% of your code's bottleneck is in 2% of your code so premature-optimization may add maintenance and safety debt that won't have any measurable impact. Instead, code for maintainability and safety, and then, and only then, when you find a true bottleneck, then you should go back and optimize further.

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Configuration "diff" across Oracle WebCenter Sites instances

- by Mark Fincham-Oracle

Problem Statement With many Oracle WebCenter Sites environments - how do you know if the various configuration assets and settings are in sync across all of those environments? Background At Oracle we typically have a "W" shaped set of environments. For the "Production" environments we typically have a disaster recovery clone as well and sometimes additional QA environments alongside the production management environment. In the case of www.java.com we have 10 different environments. All configuration assets/settings (CSElements, Templates, Start Menus etc..) start life on the Development Management environment and are then published downstream to other environments as part of the software development lifecycle. Ensuring that each of these 10 environments has the same set of Templates, CSElements, StartMenus, TreeTabs etc.. is impossible to do efficiently without automation. Solution Summary The solution comprises of two components. A JSON data feed from each environment. A simple HTML page that consumes these JSON data feeds. Data Feed: Create a JSON WebService on each environment. The WebService is no more than a SiteEntry + CSElement. The CSElement queries various DB tables to obtain details of the assets/settings returning this data in a JSON feed. Report: Create a simple HTML page that uses JQuery to fetch the JSON feed from each environment and display the results in a table. Since all assets (CSElements, Templates etc..) are published between environments they will have the same last modified date. If the last modified date of an asset is different in the JSON feed or is mising from an environment entirely then highlight that in the report table. Example Solution Details Step 1: Create a Site Entry + CSElement that outputs JSON Site Entry & CSElement Setup The SiteEntry should be uncached so that the most recent configuration information is returned at all times. In the CSElement set the contenttype accordingly: Step 2: Write the CSElement Logic The basic logic, that we repeat for each asset or setting that we are interested in, is to query the DB using <ics:sql> and then loop over the resultset with <ics:listloop>. For example: <ics:sql sql="SELECT name,updateddate FROM Template WHERE status != 'VO'" listname="TemplateList" table="Template" /> "templates": [ <ics:listloop listname="TemplateList"> {"name":"<ics:listget listname="TemplateList" fieldname="name"/>", "modified":"<ics:listget listname="TemplateList" fieldname="updateddate"/>"}, </ics:listloop> ], A comprehensive list of SQL queries to fetch each configuration asset/settings can be seen in the appendix at the end of this article. For the generation of the JSON data structure you could use Jettison (the library ships with the 11.1.1.8 version of the product), native Java 7 capabilities or (as the above example demonstrates) you could roll-your-own JSON output but that is not advised. Step 3: Create an HTML Report The JavaScript logic looks something like this.. 1) Create a list of JSON feeds to fetch: ENVS['dev-mgmngt'] = 'http://dev-mngmnt.example.com/sites/ContentServer?d=&pagename=settings.json'; ENVS['dev-dlvry'] = 'http://dev-dlvry.example.com/sites/ContentServer?d=&pagename=settings.json'; ENVS['test-mngmnt'] = 'http://test-mngmnt.example.com/sites/ContentServer?d=&pagename=settings.json'; ENVS['test-dlvry'] = 'http://test-dlvry.example.com/sites/ContentServer?d=&pagename=settings.json'; 2) Create a function to get the JSON feeds: function getDataForEnvironment(url){ return $.ajax({ type: 'GET', url: url, dataType: 'jsonp', beforeSend: function (jqXHR, settings){ jqXHR.originalEnv = env; jqXHR.originalUrl = url; }, success: function(json, status, jqXHR) { console.log('....success fetching: ' + jqXHR.originalUrl); // store the returned data in ALLDATA ALLDATA[jqXHR.originalEnv] = json; }, error: function(jqXHR, status, e) { console.log('....ERROR: Failed to get data from [' + url + '] ' + status + ' ' + e); } }); } 3) Fetch each JSON feed: for (var env in ENVS) { console.log('Fetching data for env [' + env +'].'); var promisedData = getDataForEnvironment(ENVS[env]); promisedData.success(function (data) {}); } 4) For each configuration asset or setting create a table in the report For example, CSElements: 1) Get a list of unique CSElement names from all of the returned JSON data. 2) For each unique CSElement name, create a row in the table 3) Select 1 environment to represent the master or ideal state (e.g. "Everything should be like Production Delivery") 4) For each environment, compare the last modified date of this envs CSElement to the master. Highlight any differences in last modified date or missing CSElements. 5) Repeat... Appendix This section contains various SQL statements that can be used to retrieve configuration settings from the DB. Templates <ics:sql sql="SELECT name,updateddate FROM Template WHERE status != 'VO'" listname="TemplateList" table="Template" /> CSElements <ics:sql sql="SELECT name,updateddate FROM CSElement WHERE status != 'VO'" listname="CSEList" table="CSElement" /> Start Menus <ics:sql sql="select sm.id, sm.cs_name, sm.cs_description, sm.cs_assettype, sm.cs_assetsubtype, sm.cs_itemtype, smr.cs_rolename, p.name from StartMenu sm, StartMenu_Sites sms, StartMenu_Roles smr, Publication p where sm.id=sms.ownerid and sm.id=smr.cs_ownerid and sms.pubid=p.id order by sm.id" listname="startList" table="Publication,StartMenu,StartMenu_Roles,StartMenu_Sites"/> Publishing Configurations <ics:sql sql="select id, name, description, type, dest, factors from PubTarget" listname="pubTargetList" table="PubTarget" /> Tree Tabs <ics:sql sql="select tt.id, tt.title, tt.tooltip, p.name as pubname, ttr.cs_rolename, ttsect.name as sectname from TreeTabs tt, TreeTabs_Roles ttr, TreeTabs_Sect ttsect,TreeTabs_Sites ttsites LEFT JOIN Publication p on p.id=ttsites.pubid where p.id is not null and tt.id=ttsites.ownerid and ttsites.pubid=p.id and tt.id=ttr.cs_ownerid and tt.id=ttsect.ownerid order by tt.id" listname="treeTabList" table="TreeTabs,TreeTabs_Roles,TreeTabs_Sect,TreeTabs_Sites,Publication" /> Filters <ics:sql sql="select name,description,classname from Filters" listname="filtersList" table="Filters" /> Attribute Types <ics:sql sql="select id,valuetype,name,updateddate from AttrTypes where status != 'VO'" listname="AttrList" table="AttrTypes" /> WebReference Patterns <ics:sql sql="select id,webroot,pattern,assettype,name,params,publication from WebReferencesPatterns" listname="WebRefList" table="WebReferencesPatterns" /> Device Groups <ics:sql sql="select id,devicegroupsuffix,updateddate,name from DeviceGroup" listname="DeviceList" table="DeviceGroup" /> Site Entries <ics:sql sql="select se.id,se.name,se.pagename,se.cselement_id,se.updateddate,cse.rootelement from SiteEntry se LEFT JOIN CSElement cse on cse.id = se.cselement_id where se.status != 'VO'" listname="SiteList" table="SiteEntry,CSElement" /> Webroots <ics:sql sql="select id,name,rooturl,updatedby,updateddate from WebRoot" listname="webrootList" table="WebRoot" /> Page Definitions <ics:sql sql="select pd.id, pd.name, pd.updatedby, pd.updateddate, pd.description, pdt.attributeid, pa.name as nameattr, pdt.requiredflag, pdt.ordinal from PageDefinition pd, PageDefinition_TAttr pdt, PageAttribute pa where pd.status != 'VO' and pa.id=pdt.attributeid and pdt.ownerid=pd.id order by pd.id,pdt.ordinal" listname="pageDefList" table="PageDefinition,PageAttribute,PageDefinition_TAttr" /> FW_Application <ics:sql sql="select id,name,updateddate from FW_Application where status != 'VO'" listname="FWList" table="FW_Application" /> Custom Elements <ics:sql sql="select elementname from ElementCatalog where elementname like 'CustomElements%'" listname="elementList" table="ElementCatalog" />

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Creating a Training Lab on Windows Azure

- by Michael Stephenson

Originally posted on: http://geekswithblogs.net/michaelstephenson/archive/2013/06/17/153149.aspxThis week we are preparing for a training course that Alan Smith will be running for the support teams at one of my customers around Windows Azure. In order to facilitate the training lab we have a few prerequisites we need to handle. One of the biggest ones is that although the support team all have MSDN accounts the local desktops they work on are not ideal for running most of the labs as we want to give them some additional developer background training around Azure. Some recent Azure announcements really help us in this area: MSDN software can now be used on Azure VM You don't pay for Azure VM's when they are no longer used Since the support team only have limited experience of Windows Azure and the organisation also have an Enterprise Agreement we decided it would be best value for money to spin up a training lab in a subscription on the EA and then we can turn the machines off when we are done. At the same time we would be able to spin them back up when the users need to do some additional lab work once the training course is completed. In order to achieve this I wanted to create a powershell script which would setup my training lab. The aim was to create 18 VM's which would be based on a prebuilt template with Visual Studio and the Azure development tools. The script I used is described below The Start & Variables The below text will setup the powershell environment and some variables which I will use elsewhere in the script. It will also import the Azure Powershell cmdlets. You can see below that I will need to download my publisher settings file and know some details from my Azure account. At this point I will assume you have a basic understanding of Azure & Powershell so already know how to do this. Set-ExecutionPolicy Unrestrictedcls $startTime = get-dateImport-Module "C:\Program Files (x86)\Microsoft SDKs\Windows Azure\PowerShell\Azure\Azure.psd1"# Azure Publisher Settings $azurePublisherSettings = '<Your settings file>.publishsettings' # Subscription Details $subscriptionName = "<Your subscription name>" $defaultStorageAccount = "<Your default storage account>" # Affinity Group Details $affinityGroup = '<Your affinity group>' $dataCenter = 'West Europe' # From Get-AzureLocation # VM Details $baseVMName = 'TRN' $adminUserName = '<Your admin username>' $password = '<Your admin password>' $size = 'Medium' $vmTemplate = '<The name of your VM template image>' $rdpFilePath = '<File path to save RDP files to>' $machineSettingsPath = '<File path to save machine info to>' Functions In the next section of the script I have some functions which are used to perform certain actions. The first is called CreateVM. This will do the following actions: If the VM already exists it will be deleted Create the cloud service Create the VM from the template I have created Add an endpoint so we can RDP to them all over the same port Download the RDP file so there is a short cut the trainees can easily access the machine via Write settings for the machine to a log file function CreateVM($machineNo) { # Specify a name for the new VM $machineName = "$baseVMName-$machineNo" Write-Host "Creating VM: $machineName" # Get the Azure VM Image $myImage = Get-AzureVMImage $vmTemplate #If the VM already exists delete and re-create it $existingVm = Get-AzureVM -Name $machineName -ServiceName $serviceName if($existingVm -ne $null) { Write-Host "VM already exists so deleting it" Remove-AzureVM -Name $machineName -ServiceName $serviceName } "Creating Service" $serviceName = "bupa-azure-train-$machineName" Remove-AzureService -Force -ServiceName $serviceName New-AzureService -Location $dataCenter -ServiceName $serviceName Write-Host "Creating VM: $machineName" New-AzureQuickVM -Windows -name $machineName -ServiceName $serviceName -ImageName $myImage.ImageName -InstanceSize $size -AdminUsername $adminUserName -Password $password Write-Host "Updating the RDP endpoint for $machineName" Get-AzureVM -name $machineName -ServiceName $serviceName ` | Add-AzureEndpoint -Name RDP -Protocol TCP -LocalPort 3389 -PublicPort 550 ` | Update-AzureVM Write-Host "Get the RDP File for machine $machineName" $machineRDPFilePath = "$rdpFilePath\$machineName.rdp" Get-AzureRemoteDesktopFile -name $machineName -ServiceName $serviceName -LocalPath "$machineRDPFilePath" WriteMachineSettings "$machineName" "$serviceName" } The delete machine settings function is used to delete the log file before we start re-running the process. function DeleteMachineSettings() { Write-Host "Deleting the machine settings output file" [System.IO.File]::Delete("$machineSettingsPath"); } The write machine settings function will get the VM and then record its details to the log file. The importance of the log file is that I can easily provide the information for all of the VM's to our infrastructure team to be able to configure access to all of the VM's function WriteMachineSettings([string]$vmName, [string]$vmServiceName) { Write-Host "Writing to the machine settings output file" $vm = Get-AzureVM -name $vmName -ServiceName $vmServiceName $vmEndpoint = Get-AzureEndpoint -VM $vm -Name RDP $sb = new-object System.Text.StringBuilder $sb.Append("Service Name: "); $sb.Append($vm.ServiceName); $sb.Append(", "); $sb.Append("VM: "); $sb.Append($vm.Name); $sb.Append(", "); $sb.Append("RDP Public Port: "); $sb.Append($vmEndpoint.Port); $sb.Append(", "); $sb.Append("Public DNS: "); $sb.Append($vmEndpoint.Vip); $sb.AppendLine(""); [System.IO.File]::AppendAllText($machineSettingsPath, $sb.ToString()); } # end functions Rest of Script In the rest of the script it is really just the bit that orchestrates the actions we want to happen. It will load the publisher settings, select the Azure subscription and then loop around the CreateVM function and create 16 VM's Import-AzurePublishSettingsFile $azurePublisherSettings Set-AzureSubscription -SubscriptionName $subscriptionName -CurrentStorageAccount $defaultStorageAccount Select-AzureSubscription -SubscriptionName $subscriptionName DeleteMachineSettings "Starting creating Bupa International Azure Training Lab" $numberOfVMs = 16 for ($index=1; $index -le $numberOfVMs; $index++) { $vmNo = "$index" CreateVM($vmNo); } "Finished creating Bupa International Azure Training Lab" # Give it a Minute Start-Sleep -s 60 $endTime = get-date "Script run time " + ($endTime - $startTime) Conclusion As you can see there is nothing too fancy about this script but in our case of creating a small isolated training lab which is not connected to our corporate network then we can easily use this to provision the lab. Im sure if this is of use to anyone you can easily modify it to do other things with the lab environment too. A couple of points to note are that there are some soft limits in Azure about the number of cores and services your subscription can use. You may need to contact the Azure support team to be able to increase this limit. In terms of the real business value of this approach, it was not possible to use the existing desktops to do the training on, and getting some internal virtual machines would have been relatively expensive and time consuming for our ops team to do. With the Azure option we are able to spin these machines up for a temporary period during the training course and then throw them away when we are done. We expect the costing of this test lab to be very small, especially considering we have EA pricing. As a ball park I think my 18 lab VM training environment will cost in the region of $80 per day on our EA. This is a fraction of the cost of the creation of a single VM on premise.

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Retrieving a list of eBay categories using the .NET SDK and GetCategoriesCall

- by Bill Osuch

eBay offers a .Net SDK for its Trading API - this post will show you the basics of making an API call and retrieving a list of current categories. You'll need the category ID(s) for any apps that post or search eBay. To start, download the latest SDK from https://www.x.com/developers/ebay/documentation-tools/sdks/dotnet and create a new console app project. Add a reference to the eBay.Service DLL, and a few using statements: using eBay.Service.Call; using eBay.Service.Core.Sdk; using eBay.Service.Core.Soap; I'm assuming at this point you've already joined the eBay Developer Network and gotten your app IDs and user tokens. If not: Join the developer program Generate tokens Next, add an app.config file that looks like this: <?xml version="1.0"?> <configuration> <appSettings> <add key="Environment.ApiServerUrl" value="https://api.ebay.com/wsapi"/> <add key="UserAccount.ApiToken" value="YourBigLongToken"/> </appSettings> </configuration> And then add the code to get the xml list of categories: ApiContext apiContext = GetApiContext(); GetCategoriesCall apiCall = new GetCategoriesCall(apiContext); apiCall.CategorySiteID = "0"; //Leave this commented out to retrieve all category levels (all the way down): //apiCall.LevelLimit = 4; //Uncomment this to begin at a specific parent category: //StringCollection parentCategories = new StringCollection(); //parentCategories.Add("63"); //apiCall.CategoryParent = parentCategories; apiCall.DetailLevelList.Add(DetailLevelCodeType.ReturnAll); CategoryTypeCollection cats = apiCall.GetCategories(); using (StreamWriter outfile = new StreamWriter(@"C:\Temp\EbayCategories.xml")) { outfile.Write(apiCall.SoapResponse); } GetApiContext() (provided in the sample apps in the SDK) is required for any call: static ApiContext GetApiContext() { //apiContext is a singleton, //to avoid duplicate configuration reading if (apiContext != null) { return apiContext; } else { apiContext = new ApiContext(); //set Api Server Url apiContext.SoapApiServerUrl = ConfigurationManager.AppSettings["Environment.ApiServerUrl"]; //set Api Token to access eBay Api Server ApiCredential apiCredential = new ApiCredential(); apiCredential.eBayToken = ConfigurationManager.AppSettings["UserAccount.ApiToken"]; apiContext.ApiCredential = apiCredential; //set eBay Site target to US apiContext.Site = SiteCodeType.US; return apiContext; } } Running this will give you a large (4 or 5 megs) XML file that looks something like this: <soapenv:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"> <soapenv:Body> <GetCategoriesResponse > <Timestamp>2012-06-06T16:03:46.158Z</Timestamp> <Ack>Success</Ack> <CorrelationID>d02dd9e3-295a-4268-9ea5-554eeb2e0e18</CorrelationID> <Version>775</Version> <Build>E775_CORE_BUNDLED_14891042_R1</Build> - <CategoryArray> <Category> <BestOfferEnabled>true</BestOfferEnabled> <AutoPayEnabled>true</AutoPayEnabled> <CategoryID>20081</CategoryID> <CategoryLevel>1</CategoryLevel> <CategoryName>Antiques</CategoryName> <CategoryParentID>20081</CategoryParentID> </Category> <Category> <BestOfferEnabled>true</BestOfferEnabled> <AutoPayEnabled>true</AutoPayEnabled> <CategoryID>37903</CategoryID> <CategoryLevel>2</CategoryLevel> <CategoryName>Antiquities</CategoryName> <CategoryParentID>20081</CategoryParentID> </Category> (etc.) You could work with this, but I wanted a nicely nested view, like this: <CategoryArray> <Category Name='Antiques' ID='20081' Level='1'> <Category Name='Antiquities' ID='37903' Level='2'/> </CategoryArray> ...so I transformed the xml: private void TransformXML(CategoryTypeCollection cats) { XmlElement topLevelElement = null; XmlElement childLevelElement = null; XmlNode parentNode = null; string categoryString = ""; XmlDocument returnDoc = new XmlDocument(); XmlElement root = returnDoc.CreateElement("CategoryArray"); returnDoc.AppendChild(root); XmlNode rootNode = returnDoc.SelectSingleNode("/CategoryArray"); //Loop through CategoryTypeCollection foreach (CategoryType category in cats) { if (category.CategoryLevel == 1) { //Top-level category, so we know we can just add it topLevelElement = returnDoc.CreateElement("Category"); topLevelElement.SetAttribute("Name", category.CategoryName); topLevelElement.SetAttribute("ID", category.CategoryID); rootNode.AppendChild(topLevelElement); } else { // Level number will determine how many Category nodes we are deep categoryString = ""; for (int x = 1; x < category.CategoryLevel; x++) { categoryString += "/Category"; } parentNode = returnDoc.SelectSingleNode("/CategoryArray" + categoryString + "[@ID='" + category.CategoryParentID[0] + "']"); childLevelElement = returnDoc.CreateElement("Category"); childLevelElement.SetAttribute("Name", category.CategoryName); childLevelElement.SetAttribute("ID", category.CategoryID); parentNode.AppendChild(childLevelElement); } } returnDoc.Save(@"C:\Temp\EbayCategories-Modified.xml"); } Yes, there are probably much cleaner ways of dealing with it, but I'm not an xml expert… Keep in mind, eBay categories do not change on a regular basis, so you should be able to cache this data (either in a file or database) for some time. The xml returns a CategoryVersion node that you can use to determine if the category list has changed. Technorati Tags: Csharp, eBay

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The Future of Project Management is Social

- by Natalia Rachelson

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} A guest post by Kazim Isfahani, Director, Product Marketing, Oracle Rapid Ascent. Breakneck Speed. Lightning Fast. Perhaps even overwhelming. No matter which set of adjectives we use to describe it, social media’s rise into the enterprise mainstream has been unprecedented. Indeed, the big 4 social media powerhouses (Facebook, Google+, LinkedIn, and Twitter), have nearly 2 Billion users between them. You may be asking (as you should really) “That’s all well and good for the consumer, but for me at my company, what’s your point? Beyond the fact that I can check and post updates, that is.” Good question, kind sir. Impact of Social and Collaboration on Project Management I’ll dovetail this discussion to the project management realm, since that’s what I’m writing about. Speed is a big challenge for project-driven organizations. Anything that can help speed up project delivery - be it a new product introduction effort or a geographical expansion project - fast is a good thing. So where does this whole social thing fit particularly since there are already a host of tools to help with traditional project execution? The fact is companies have seen improvements in their productivity by deploying departmental collaboration and other social-oriented solutions. McKinsey’s survey on social tools shows we have reached critical scale: 72% of respondents report that their companies use at least one and over 40% say they are using social networks and blogs. We don’t hear as much about the impact of social media technologies at the project and project manager level, but that does not mean there is none. Consider the new hire. The type of individual entering the workforce and executing on projects is a generation of worker expecting visually appealing, easy to use and easy to understand technology meshing hand-in-hand with business processes. Consider the project manager. The social era has enhanced the role that the project manager must play. Today’s project manager must be a supreme communicator, an influencer, a sympathizer, a negotiator, and still manage to keep all stakeholders in the loop on project progress. Social tools play a significant role in this effort. Now consider the impact to the project team. The way that a project team functions has changed, with newer, social oriented technologies making the process of information dissemination and team communications much more fluid. It’s clear that a shift is occurring where “social” is intersecting with project management. The Rise of Social Project Management We refer to the melding of project management and social networking as Social Project Management. Social Project Management is based upon the philosophy that the project team is one part of an integrated whole, and that valuable and unique abilities exist within the larger organization. For this reason, Social Project Management systems should be integrated into the collaborative platform(s) of an organization, allowing communication to proceed outside the project boundaries. What makes social project management "social" is an implicit awareness where distributed teams build connected links in ways that were previously restricted to teams that were co-located. Just as critical, Social Project Management embraces the vision of seamless online collaboration within a project team, but also provides for, (and enhances) the use of rigorous project management techniques. Social Project Management acknowledges that projects (particularly large projects) are a social activity - people doing work with people, for other people, with commitments to yet other people. The more people (larger projects), the more interpersonal the interactions, and the more social affects the project. The Epitome of Social - Fusion Project Portfolio Management If I take this one level further to discuss Fusion Project Portfolio Management, the notion of Social Project Management is on full display. With Fusion Project Portfolio Management, project team members have a single place for interaction on projects and access to any other resources working within the Fusion ERP applications. This allows team members the opportunity to be informed with greater participation and provide better information. The application’s the visual appeal, and highly graphical nature makes it easy to navigate information. The project activity stream adds to the intuitive user experience. The goal of productivity is pervasive throughout Fusion Project Portfolio Management. Field research conducted with Oracle customers and partners showed that users needed a way to stay in the context of their core transactions and yet easily access social networking tools. This is manifested in the application so when a user executes a business process, they not only have the transactional application at their fingertips, but also have things like e-mail, SMS, text, instant messaging, chat – all providing a number of different ways to interact with people and/or groups of people, both internal and external to the project and enterprise. But in the end, connecting people is relatively easy. The larger issue is finding a way to serve up relevant, system-generated, actionable information, in real time, which will allow for more streamlined execution on key business processes. Fusion Project Portfolio Management’s design concept enables users to create project communities, establish discussion threads, manage event calendars as well as deliver project based work spaces to organize communications within the context of a project – all within a secure business environment. We’d love to hear from you and get your thoughts and ideas about how Social Project Management is impacting your organization. To learn more about Oracle Fusion Project Portfolio Management, please visit this link

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A star algorithm implementation problems

- by bryan226

I’m having some trouble implementing the A* algorithm in a 2D tile based game. The problem is basically that the algorithm gets stuck when something gets in its direct way (e.g. walls) Note that it only allows Horizontal and Vertical movement. Here's a picture as it works fine across the map without something in its direct way: (Green tile = destination, Blue = In closed list, Green = in open list) This is what happens if I try to walk 'around' a wall: I calculate costs with the F = G + H formula: G = 1 Cost per Step H = 10 Cost per Step //Count how many tiles are between current-tile & destination-tile The functions: short c_astar::GuessH(short Startx,short Starty,short Destinationx,short Destinationy) { hgeVector Start, Destination; Start.x = Startx; Start.y = Starty; Destination.x = Destinationx; Destination.y = Destinationy; short a = 0; short b = 0; if(Start.x > Destination.x) a = Start.x - Destination.x; else a = Destination.x - Start.x; if(Start.y > Destination.y) b = Start.y - Destination.y; else b = Destination.y - Start.y; return (a+b)*10; } short c_astar::GuessG(short Startx,short Starty,short Currentx,short Currenty) { hgeVector Start, Destination; Start.x = Startx; Start.y = Starty; Destination.x = Currentx; Destination.y = Currenty; short a = 0; short b = 0; if(Start.x > Destination.x) a = Start.x - Destination.x; else a = Destination.x - Start.x; if(Start.y > Destination.y) b = Start.y - Destination.y; else b = Destination.y - Start.y; return (a+b); } At the end of the loop I check which tile is the cheapest to go according to its F value: Then some quick checks are done for each tile (UP,DOWN,LEFT,RIGHT): //...CX are holding the F value of the TILE specified // Info: C0 = Center (Current) // C1 = UP // C2 = DOWN // C3 = LEFT // C4 = RIGHT //Quick checks if(((C1 < C2) && (C1 < C3) && (C1 < C4))) { Current.y -= 1; bSimilar = false; if(DEBUG) hge->System_Log("C1 < ALL"); } //.. same for C2,C3 & C4 If there are multiple tiles with the same F value: It’s actually a switch for DOWNLEFT,UPRIGHT.. etc. Here’s one of it: case UPRIGHT: { //UP Temporary = Current; Temporary.y -= 1; bTileStatus[0] = IsTileWalkable(Temporary.x,Temporary.y); if(bTileStatus[0]) { //Proceed normal we are OK & walkable Tilex.Tile = map.at(Temporary.y).at(Temporary.x); //Search in lists if(SearchInClosedList(Tilex.Tile.ID,C0)) bFoundInClosedList[0] = true; if(SearchInOpenList(Tilex.Tile.ID,C0)) bFoundInOpenList[0] = true; //RIGHT Temporary = Current; Temporary.x += 1; bTileStatus[1] = IsTileWalkable(Temporary.x,Temporary.y); if(bTileStatus[1]) { //Proceed normal we are OK & walkable Tilex.Tile = map.at(Temporary.y).at(Temporary.x); //Search in lists if(SearchInClosedList(Tilex.Tile.ID,C0)) bFoundInClosedList[1] = true; if(SearchInOpenList(Tilex.Tile.ID,C0)) bFoundInOpenList[1] = true; //************************************************* // Purpose: ClosedList behavior //************************************************* if(bFoundInClosedList[0] && !bFoundInClosedList[1]) { //UP found in ClosedList. Go RIGHT return RIGHT; } if(!bFoundInClosedList[0] && bFoundInClosedList[1]) { //RIGHT found in ClosedList. Go UP return UP; } if(bFoundInClosedList[0] && bFoundInClosedList[1]) { //Both found in ClosedList. Random value switch(hge->Random_Int(8,9)) { case 8: return UP; break; case 9: return RIGHT; break; } } //************************************************* // Purpose: OpenList behavior //************************************************* if(bFoundInOpenList[0] && !bFoundInOpenList[1]) { //UP found in OpenList. Go RIGHT return RIGHT; } if(!bFoundInOpenList[0] && bFoundInOpenList[1]) { //RIGHT found in OpenList. Go UP return UP; } if(bFoundInOpenList[0] && bFoundInOpenList[1]) { //Both found in OpenList. Random value switch(hge->Random_Int(8,9)) { case 8: return UP; break; case 9: return RIGHT; break; } } } else if(!bTileStatus[1]) { //RIGHT is not walkable OR out of range //Choose UP return UP; } } else if(!bTileStatus[0]) { //UP is not walkable OR out of range //Fast check RIGHT Temporary = Current; Temporary.x += 1; bTileStatus[1] = IsTileWalkable(Temporary.x,Temporary.y); if(bTileStatus[1]) { return RIGHT; } else return FAILED; //Failed, no valid path found! } } break; A log for the second picture: (Cut down to ten passes, because it’s just repeating itself) ----------------------------------------------------- PASS: 1 | C1: 211 | C2: 191 | C3: 211 | C4: 191 DOWN + RIGHT SIMILAR Going DOWN ----------------------------------------------------- PASS: 2 | C1: 200 | C2: 182 | C3: 202 | C4: 182 DOWN + RIGHT SIMILAR Going DOWN ----------------------------------------------------- PASS: 3 | C1: 191 | C2: 193 | C3: 193 | C4: 173 C4 < ALL Tile(12.000000,6.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 4 | C1: 182 | C2: 184 | C3: 182 | C4: 999 UP + LEFT SIMILAR Going UP Tile(12.000000,5.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 5 | C1: 191 | C2: 173 | C3: 191 | C4: 999 C2 < ALL Tile(12.000000,6.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 6 | C1: 182 | C2: 184 | C3: 182 | C4: 999 UP + LEFT SIMILAR Going UP Tile(12.000000,5.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 7 | C1: 191 | C2: 173 | C3: 191 | C4: 999 C2 < ALL Tile(12.000000,6.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 8 | C1: 182 | C2: 184 | C3: 182 | C4: 999 UP + LEFT SIMILAR Going LEFT ----------------------------------------------------- PASS: 9 | C1: 191 | C2: 193 | C3: 193 | C4: 173 C4 < ALL Tile(12.000000,6.000000) not walkable. MAX_F_VALUE set. ----------------------------------------------------- PASS: 10 | C1: 182 | C2: 184 | C3: 182 | C4: 999 UP + LEFT SIMILAR Going LEFT ----------------------------------------------------- Its always going after the cheapest F value, which seems to be wrong. If someone could point me to the right direction I'd be thankful. Regards, bryan226

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My vertex shader doesn't affect texture coords or diffuse info but works for position

- by tina nyaa

I am new to 3D and DirectX - in the past I have only used abstractions for 2D drawing. Over the past month I've been studying really hard and I'm trying to modify and adapt some of the shaders as part of my personal 'study project'. Below I have a shader, modified from one of the Microsoft samples. I set diffuse and tex0 vertex shader outputs to zero, but my model still shows the full texture and lighting as if I hadn't changed the values from the vertex buffer. Changing the position of the model works, but nothing else. Why is this? // // Skinned Mesh Effect file // Copyright (c) 2000-2002 Microsoft Corporation. All rights reserved. // float4 lhtDir = {0.0f, 0.0f, -1.0f, 1.0f}; //light Direction float4 lightDiffuse = {0.6f, 0.6f, 0.6f, 1.0f}; // Light Diffuse float4 MaterialAmbient : MATERIALAMBIENT = {0.1f, 0.1f, 0.1f, 1.0f}; float4 MaterialDiffuse : MATERIALDIFFUSE = {0.8f, 0.8f, 0.8f, 1.0f}; // Matrix Pallette static const int MAX_MATRICES = 100; float4x3 mWorldMatrixArray[MAX_MATRICES] : WORLDMATRIXARRAY; float4x4 mViewProj : VIEWPROJECTION; /////////////////////////////////////////////////////// struct VS_INPUT { float4 Pos : POSITION; float4 BlendWeights : BLENDWEIGHT; float4 BlendIndices : BLENDINDICES; float3 Normal : NORMAL; float3 Tex0 : TEXCOORD0; }; struct VS_OUTPUT { float4 Pos : POSITION; float4 Diffuse : COLOR; float2 Tex0 : TEXCOORD0; }; float3 Diffuse(float3 Normal) { float CosTheta; // N.L Clamped CosTheta = max(0.0f, dot(Normal, lhtDir.xyz)); // propogate scalar result to vector return (CosTheta); } VS_OUTPUT VShade(VS_INPUT i, uniform int NumBones) { VS_OUTPUT o; float3 Pos = 0.0f; float3 Normal = 0.0f; float LastWeight = 0.0f; // Compensate for lack of UBYTE4 on Geforce3 int4 IndexVector = D3DCOLORtoUBYTE4(i.BlendIndices); // cast the vectors to arrays for use in the for loop below float BlendWeightsArray[4] = (float[4])i.BlendWeights; int IndexArray[4] = (int[4])IndexVector; // calculate the pos/normal using the "normal" weights // and accumulate the weights to calculate the last weight for (int iBone = 0; iBone < NumBones-1; iBone++) { LastWeight = LastWeight + BlendWeightsArray[iBone]; Pos += mul(i.Pos, mWorldMatrixArray[IndexArray[iBone]]) * BlendWeightsArray[iBone]; Normal += mul(i.Normal, mWorldMatrixArray[IndexArray[iBone]]) * BlendWeightsArray[iBone]; } LastWeight = 1.0f - LastWeight; // Now that we have the calculated weight, add in the final influence Pos += (mul(i.Pos, mWorldMatrixArray[IndexArray[NumBones-1]]) * LastWeight); Normal += (mul(i.Normal, mWorldMatrixArray[IndexArray[NumBones-1]]) * LastWeight); // transform position from world space into view and then projection space //o.Pos = mul(float4(Pos.xyz, 1.0f), mViewProj); o.Pos = mul(float4(Pos.xyz, 1.0f), mViewProj); o.Diffuse.x = 0.0f; o.Diffuse.y = 0.0f; o.Diffuse.z = 0.0f; o.Diffuse.w = 0.0f; o.Tex0 = float2(0,0); return o; } technique t0 { pass p0 { VertexShader = compile vs_3_0 VShade(4); } } I am currently using the SlimDX .NET wrapper around DirectX, but the API is extremely similar: public void Draw() { var device = vertexBuffer.Device; device.Clear(ClearFlags.Target | ClearFlags.ZBuffer, Color.White, 1.0f, 0); device.SetRenderState(RenderState.Lighting, true); device.SetRenderState(RenderState.DitherEnable, true); device.SetRenderState(RenderState.ZEnable, true); device.SetRenderState(RenderState.CullMode, Cull.Counterclockwise); device.SetRenderState(RenderState.NormalizeNormals, true); device.SetSamplerState(0, SamplerState.MagFilter, TextureFilter.Anisotropic); device.SetSamplerState(0, SamplerState.MinFilter, TextureFilter.Anisotropic); device.SetTransform(TransformState.World, Matrix.Identity * Matrix.Translation(0, -50, 0)); device.SetTransform(TransformState.View, Matrix.LookAtLH(new Vector3(-200, 0, 0), Vector3.Zero, Vector3.UnitY)); device.SetTransform(TransformState.Projection, Matrix.PerspectiveFovLH((float)Math.PI / 4, (float)device.Viewport.Width / device.Viewport.Height, 10, 10000000)); var material = new Material(); material.Ambient = material.Diffuse = material.Emissive = material.Specular = new Color4(Color.White); material.Power = 1f; device.SetStreamSource(0, vertexBuffer, 0, vertexSize); device.VertexDeclaration = vertexDeclaration; device.Indices = indexBuffer; device.Material = material; device.SetTexture(0, texture); var param = effect.GetParameter(null, "mWorldMatrixArray"); var boneWorldTransforms = bones.OrderedBones.OrderBy(x => x.Id).Select(x => x.CombinedTransformation).ToArray(); effect.SetValue(param, boneWorldTransforms); effect.SetValue(effect.GetParameter(null, "mViewProj"), Matrix.Identity);// Matrix.PerspectiveFovLH((float)Math.PI / 4, (float)device.Viewport.Width / device.Viewport.Height, 10, 10000000)); effect.SetValue(effect.GetParameter(null, "MaterialDiffuse"), material.Diffuse); effect.SetValue(effect.GetParameter(null, "MaterialAmbient"), material.Ambient); effect.Technique = effect.GetTechnique(0); var passes = effect.Begin(FX.DoNotSaveState); for (var i = 0; i < passes; i++) { effect.BeginPass(i); device.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, skin.Vertices.Length, 0, skin.Indicies.Length / 3); effect.EndPass(); } effect.End(); } Again, I set diffuse and tex0 vertex shader outputs to zero, but my model still shows the full texture and lighting as if I hadn't changed the values from the vertex buffer. Changing the position of the model works, but nothing else. Why is this? Also, whatever I set in the bone transformation matrices doesn't seem to have an effect on my model. If I set every bone transformation to a zero matrix, the model still shows up as if nothing had happened, but changing the Pos field in shader output makes the model disappear. I don't understand why I'm getting this kind of behaviour. Thank you!

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Lambda’s for .NET made easy…

- by mbcrump

The purpose of my blog is to explain things for a beginner to intermediate c# programmer. I’ve seen several blog post that use lambda expressions always assuming the audience is familiar with them. The purpose of this post is to make them simple and easily understood. Let’s begin with a definition. A lambda expression is an anonymous function that can contain expressions and statements, and can be used to create delegates or expression tree types. So anonymous function… delegates or expression tree types? I don’t get it??? Confused yet? Lets break this into a few definitions and jump right into the code. anonymous function – is an "inline" statement or expression that can be used wherever a delegate type is expected. delegate - is a type that references a method. Once a delegate is assigned a method, it behaves exactly like that method. The delegate method can be used like any other method, with parameters and a return value. Expression trees - represent code in a tree-like data structure, where each node is an expression, for example, a method call or a binary operation such as x < y. Don’t worry if this still sounds confusing, lets jump right into the code with a simple 3 line program. We are going to use a Function Delegate (all you need to remember is that this delegate returns a value.) Lambda expressions are used most commonly with the Func and Action delegates, so you will see an example of both of these. Lambda Expression 3 lines. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication7 { class Program { static void Main(string[] args) { Func<int, int> myfunc = x => x *x; Console.WriteLine(myfunc(6).ToString()); Console.ReadLine(); } } } Is equivalent to Old way of doing it. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication7 { class Program { static void Main(string[] args) { Console.WriteLine(myFunc(6).ToString()); Console.ReadLine(); } static int myFunc(int x) { return x * x; } } } In the example, there is a single parameter, x, and the expression is x*x. I’m going to stop here to make sure you are still with me. A lambda expression is an unnamed method written in place of a delegate instance. In other words, the compiler converts the lambda expression to either a : A delegate instance An expression tree All lambda have the following form: (parameters) => expression or statement block Now look back to the ones we have created. It should start to sink in. Don’t get stuck on the => form, use it as an identifier of a lambda. A Lamba expression can also be written in the following form: Lambda Expression. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication7 { class Program { static void Main(string[] args) { Func<int, int> myFunc = x => { return x * x; }; Console.WriteLine(myFunc(6).ToString()); Console.ReadLine(); } } } This form may be easier to read but consumes more space. Lets try an Action delegate – this delegate does not return a value. Action Delegate example. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication7 { class Program { static void Main(string[] args) { Action<string> myAction = (string x) => { Console.WriteLine(x); }; myAction("michael has made this so easy"); Console.ReadLine(); } } } Lambdas can also capture outer variables (such as the example below) A lambda expression can reference the local variables and parameters of the method in which it’s defined. Outer variables referenced by a lambda expression are called captured variables. Capturing Outer Variables using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication7 { class Program { static void Main(string[] args) { string mike = "Michael"; Action<string> myAction = (string x) => { Console.WriteLine("{0}{1}", mike, x); }; myAction(" has made this so easy"); Console.ReadLine(); } } } Lamba’s can also with a strongly typed list to loop through a collection. Used w a strongly typed list. using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace ConsoleApplication7 { class Program { static void Main(string[] args) { List<string> list = new List<string>() { "1", "2", "3", "4" }; list.ForEach(s => Console.WriteLine(s)); Console.ReadLine(); } } } Outputs: 1 2 3 4 I think this will get you started with Lambda’s, as always consult the MSDN documentation for more information. Still confused? Hopefully you are not.

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Loaded OBJ Model Will Not Display in OpenGL / C++ Project

- by Drake Summers

I have been experimenting with new effects in game development. The programs I have written have been using generic shapes for the visuals. I wanted to test the effects on something a bit more complex, and wrote a resource loader for Wavefront OBJ files. I started with a simple cube in blender, exported it to an OBJ file with just vertices and triangulated faces, and used it to test the resource loader. I could not get the mesh to show up in my application. The loader never gave me any errors, so I wrote a snippet to loop through my vertex and index arrays that were returned from the loader. The data is exactly the way it is supposed to be. So I simplified the OBJ file by editing it directly to just show a front facing square. Still, nothing is displayed in the application. And don't worry, I did check to make sure that I decreased the value of each index by one while importing the OBJ. - BEGIN EDIT I also tested using glDrawArrays(GL_TRIANGLES, 0, 3 ); to draw the first triangle and it worked! So the issue could be in the binding of the VBO/IBO items. END EDIT - INDEX/VERTEX ARRAY OUTPUT: GLOBALS AND INITIALIZATION FUNCTION: GLuint program; GLint attrib_coord3d; std::vector<GLfloat> vertices; std::vector<GLushort> indices; GLuint vertexbuffer, indexbuffer; GLint uniform_mvp; int initialize() { if (loadModel("test.obj", vertices, indices)) { GLfloat myverts[vertices.size()]; copy(vertices.begin(), vertices.end(), myverts); GLushort myinds[indices.size()]; copy(indices.begin(), indices.end(), myinds); glGenBuffers(1, &vertexbuffer); glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer); glBufferData(GL_ARRAY_BUFFER, sizeof(myverts), myverts, GL_STATIC_DRAW); glGenBuffers(1, &indexbuffer); glBindBuffer(GL_ARRAY_BUFFER, indexbuffer); glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(myinds), myinds, GL_STATIC_DRAW); // OUTPUT DATA FROM NEW ARRAYS TO CONSOLE // ERROR HANDLING OMITTED FOR BREVITY } GLint link_result = GL_FALSE; GLuint vert_shader, frag_shader; if ((vert_shader = create_shader("tri.v.glsl", GL_VERTEX_SHADER)) == 0) return 0; if ((frag_shader = create_shader("tri.f.glsl", GL_FRAGMENT_SHADER)) == 0) return 0; program = glCreateProgram(); glAttachShader(program, vert_shader); glAttachShader(program, frag_shader); glLinkProgram(program); glGetProgramiv(program, GL_LINK_STATUS, &link_result); // ERROR HANDLING OMITTED FOR BREVITY const char* attrib_name; attrib_name = "coord3d"; attrib_coord3d = glGetAttribLocation(program, attrib_name); // ERROR HANDLING OMITTED FOR BREVITY const char* uniform_name; uniform_name = "mvp"; uniform_mvp = glGetUniformLocation(program, uniform_name); // ERROR HANDLING OMITTED FOR BREVITY return 1; } RENDERING FUNCTION: glm::mat4 model = glm::translate(glm::mat4(1.0f), glm::vec3(0.0, 0.0, -4.0)); glm::mat4 view = glm::lookAt(glm::vec3(0.0, 0.0, 4.0), glm::vec3(0.0, 0.0, 3.0), glm::vec3(0.0, 1.0, 0.0)); glm::mat4 projection = glm::perspective(45.0f, 1.0f*(screen_width/screen_height), 0.1f, 10.0f); glm::mat4 mvp = projection * view * model; int size; glUseProgram(program); glUniformMatrix4fv(uniform_mvp, 1, GL_FALSE, glm::value_ptr(mvp)); glClearColor(0.5, 0.5, 0.5, 1.0); glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); glEnableVertexAttribArray(attrib_coord3d); glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer); glVertexAttribPointer(attrib_coord3d, 3, GL_FLOAT, GL_FALSE, 0, 0); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexbuffer); glGetBufferParameteriv(GL_ELEMENT_ARRAY_BUFFER, GL_BUFFER_SIZE, &size); glDrawElements(GL_TRIANGLES, size/sizeof(GLushort), GL_UNSIGNED_SHORT, 0); glDisableVertexAttribArray(attrib_coord3d); VERTEX SHADER: attribute vec3 coord3d; uniform mat4 mvp; void main(void) { gl_Position = mvp * vec4(coord3d, 1.0); } FRAGMENT SHADER: void main(void) { gl_FragColor[0] = 0.0; gl_FragColor[1] = 0.0; gl_FragColor[2] = 1.0; gl_FragColor[3] = 1.0; } OBJ RESOURCE LOADER: bool loadModel(const char * path, std::vector<GLfloat> &out_vertices, std::vector<GLushort> &out_indices) { std::vector<GLfloat> temp_vertices; std::vector<GLushort> vertexIndices; FILE * file = fopen(path, "r"); // ERROR HANDLING OMITTED FOR BREVITY while(1) { char lineHeader[128]; int res = fscanf(file, "%s", lineHeader); if (res == EOF) { break; } if (strcmp(lineHeader, "v") == 0) { float _x, _y, _z; fscanf(file, "%f %f %f\n", &_x, &_y, &_z ); out_vertices.push_back(_x); out_vertices.push_back(_y); out_vertices.push_back(_z); } else if (strcmp(lineHeader, "f") == 0) { unsigned int vertexIndex[3]; int matches = fscanf(file, "%d %d %d\n", &vertexIndex[0], &vertexIndex[1], &vertexIndex[2]); out_indices.push_back(vertexIndex[0] - 1); out_indices.push_back(vertexIndex[1] - 1); out_indices.push_back(vertexIndex[2] - 1); } else { ... } } // ERROR HANDLING OMITTED FOR BREVITY return true; } I can edit the question to provide any further info you may need. I attempted to provide everything of relevance and omit what may have been unnecessary. I'm hoping this isn't some really poor mistake, because I have been at this for a few days now. If anyone has any suggestions or advice on the matter, I look forward to hearing it. As a final note: I added some arrays into the code with manually entered data, and was able to display meshes by using those arrays instead of the generated ones. I do not understand!

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“It’s only test code…”

- by Chris George

“Let me hack this in, it’s only test code”, “Don’t worry about getting it reviewed, it’s only test code”, “It doesn’t have to be elegant or efficient, it’s only test code”… do these phrases sound familiar? Chances are if you’ve working with test automation, at one point or other you will have heard these phrases, you have probably even used them yourself! What is certain is that code written under this “it’s only test code” mantra will come back and bite you in the arse! I’ve recently encountered a case where a test was giving a false positive, therefore hiding a real product bug because that test code was very badly written. Firstly it was very difficult to understand what the test was actually trying to achieve let alone how it was doing it, and this complexity masked a simple logic error. These issues are real and they do happen. Let’s take a step back from this and look at what we are trying to do. We are writing test code that tests product code, and we do this to create a suite of tests that will help protect our software against regressions. This test code is making sure that the product behaves as it should by employing some sort of expected result verification. The simple cases of these are generally not a problem. However, automation allows us to explore more complex scenarios in many more permutations. As this complexity increases then so does the complexity of the test code. It is at this point that code which has not been architected properly will cause problems. Keep your friends close… So, how do we make sure we are doing it right? The development teams I have worked on have always had Test Engineers working very closely with their Software Engineers. This is something that I have always tried to take full advantage of. They are coding experts! So run your ideas past them, ask for advice on how to structure your code, help you design your data structures. This may require a shift in your teams viewpoint, as contrary to this section title and folklore, Software Engineers are not actually the mortal enemy of Test Engineers. As time progresses, and test automation becomes more and more ingrained in what we do, the two roles are converging more than ever. Over the 16 years I have spent as a Test Engineer, I have seen the grey area between the two roles grow significantly larger. This serves to strengthen the relationship and common bond between the two roles which helps to make test code activities so much easier! Pair for the win Possibly the best thing you could do to write good test code is to pair program on the task. This will serve a few purposes. you will get the benefit of the Software Engineers knowledge and experience the Software Engineer will gain knowledge on the testing process. Sharing the love is a wonderful thing! two pairs of eyes are always better than one… And so are two brains. Between the two of you, I will guarantee you will derive more useful test cases than if it was just one of you. Code reviews Another policy which certainly pays dividends is the practice of code reviews. By having one of your peers review your code before you commit it serves two purposes. Firstly, it forces you to explain your code. Just the act of doing this will often pick up errors in your code. Secondly, it gets yet another pair of eyes on your code! I cannot stress enough how important code reviews are. The benefits they offer apply as much to product code as test code. In short, Software and Test Engineers should all be doing them! It can be extended even further by getting test code reviewed by a Software Engineer and a Test Engineer, and likewise product code. This serves to keep both functions in the loop with changes going on within your code base. Learn from your devs I briefly touched on this earlier but I’d like to go into more detail here. Pairing with your Software Engineers when writing your test code is such an amazing opportunity to improve your coding skills. As I sit here writing this article waiting to be called into court for jury service, it reminds me that it takes a lot of patience to be a Test Engineer, almost as much as it takes to be a juror! However tempting it is to go rushing in and start writing your automated tests, resist that urge. Discuss what you want to achieve then talk through the approach you’re going to take. Then code it up together. I find it really enlightening to ask questions like ‘is there a better way to do this?’ Or ‘is this how you would code it?’ The latter question, especially, is where I learn the most. I’ve found that most Software Engineers will be reluctant to show you the ‘right way’ to code something when writing tests because they perceive the ‘right way’ to be too complicated for the Test Engineer (e.g. not mentioning LINQ and instead doing something verbose). So by asking how THEY would code it, it unleashes their true dev-ness and advanced code usually ensues! I would like to point out, however, that you don’t have to accept their method as the final answer. On numerous occasions I have opted for the more simple/verbose solution because I found the code written by the Software Engineer too advanced and therefore I would find it unreadable when I return to the code in a months’ time! Always keep the target audience in mind when writing clever code, and in my case that is mostly Test Engineers.

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Simplifying Human Capital Management with Mobile Applications

- by HCM-Oracle

By Aaron Green If you're starting to think 'mobility' is a recurring theme in your reading, you'd be right. For those who haven't started to build organisational capabilities to leverage it, it's fair to say you're late to the party. The good news: better late than never. Research firm eMarketer says the worldwide smartphone audience will total 1.75 billion this year, while communications technology and services provider Ericsson suggests smartphones will triple to 5.6 billion globally by 2019. It should be no surprise, smart phone adoption is reaching the farthest corners of the globe; the subsequent impact of enterprise applications enabled by these devices is driving business performance improvement and will continue to do so. Companies using advanced workforce analytics can add significantly to the bottom line, while impacting customer satisfaction, quality and productivity. It's a statement that makes most business leaders sit forward in their chairs. Achieving these three standards is like sipping The Golden Elixir for the business world. No-one would argue their importance. So what are 'advanced workforce analytics?' Simply, they're unprecedented access to workforce trends and performance markers. Many are made possible by a mobile world and the enterprise applications that come with it on smart devices. Some refer to it as 'the consumerisation of IT'. As this phenomenon has matured and become more widely appreciated it has impacted the spectrum of functional units within an enterprise differently, but powerfully. Whether it's sales, HR, marketing, IT, or operations, all have benefited from a more mobile approach. It has been the catalyst for improvement in, and management of, the employee experience. The net result of which is happier customers. The obvious benefits but the lesser realised impact Most people understand that mobility allows for greater efficiency and productivity, collaboration and flexibility, but how that translates into business outcomes within the various functional groups is lesser known. In actuality mobility has helped galvanise partnerships between cross-functional groups within the enterprise. Where in some quarters it was once feared mobility could fragment a workforce, its rallying cry of support is coming from what you might describe as an unlikely source - HR. As the bedrock of an enterprise, it is conceivable HR might contemplate the possible negative impact of a mobile workforce that no-longer sits in an office, at the same desks every day. After all, who would know what they were doing or saying? How would they collaborate? It's reasonable to see why HR might have a legitimate claim to try and retain as much 'perceived control' as possible. The reality however is mobility has emancipated human capital and its management. Mobility and enterprise applications are expediting decision making. Google calls it Zero Moment of Truth, or ZMOT. It enables smoother operation and can contribute to faster growth. From a collaborative perspective, with the growing use of enterprise social media, which in many cases is being driven by HR, workforce planning and the tangible impact of change is much easier to map. This in turn provides a platform from which individuals and teams can thrive. With more agility and ability to anticipate, staff satisfaction and retention is higher, and real time feedback constant. The management team can save time, energy and costs with more accurate data, which is then intelligently applied across the workforce to truly engage with staff, customers and partners. From a human capital management (HCM) perspective, mobility can help you close the loop on true talent management. It can enhance what managers can offer and what employees can provide in return. It can create nested relationships and powerful partnerships. IT and HR - partners and stewards of mobility One effect of enterprise mobility is an evolution in the nature of the relationship between HR and IT from one of service provision to partnership. The reason for the dynamic shift is largely due to the 'bring your own device' (BYOD) movement, which is transitioning to a 'bring your own application' (BYOA) scenario. As enterprise technology has in some ways reverse-engineered its solutions to help manage this situation, the partnership between IT (the functional owner) and HR (the strategic enabler) is deeply entrenched. And it has to be. The CIO and the HR leader are faced with compliance and regulatory issues and concerns around information security and personal privacy on a daily basis, complicated by global reach and varied domestic legislation. There are tens of thousands of new mobile apps entering the market each month and, unlike many consumer applications which get downloaded but are often never opened again after initial perusal, enterprise applications are being relied upon by functional groups, not least by HR to enhance people management. It requires a systematic approach across all applications in use within the enterprise in order to ensure they're used to best effect. No turning back, and no desire to With real time analytics on performance and the ability for immediate feedback, there is no turning back for managers. In my experience with Oracle, our customers' operational efficiency is at record levels. It's clear as a result of the combination of individual KPIs and organisational goals, CIOs have been able to give HR leaders the ability to build predictive models that feed into an enterprise organisations' evolving strategy. It also helps them ensure regulatory compliance much more easily. Once an arduous task, with mobile enabled automation and quality data, compliance is simpler. Their world has changed for the better. For the CIO, mobility also assists them to optimise performance. While it doesn't come without challenges, mobile-enabled applications and the native experience users have with them means employees don't need high-level technical expertise to train users. It reduces the training and engagement required from the IT team so they can focus on other things that deliver value to the bottom line; all the while lowering the cost of assets and related maintenance work by simplifying processes. Rewards of a mobile enterprise outweigh risks With mobile tools allowing us to increasingly integrate our personal and professional lives, terms like "office hours" are becoming irrelevant, so work/life balance is a cultural must. Enterprises are expected to offer tools that enable workers to access information from anywhere, at any time, from any device. Employees want simplicity and convenience but it doesn't stop at private enterprise. This is a societal shift. Governments, which traditionally have been known to be slower to adopt newer technology, are also offering support for local businesses to go mobile. Several state government websites have advice on how to create mobile apps and more. And as recently as last week the Victorian Minister for Technology Gordon Rich-Phillips unveiled his State government's ICT roadmap for the next two years, which details an increased use of the public cloud, as well as mobile communications, and improved access to online data-sets. Tech giants are investing significantly in solutions designed to simplify mobile deployment and enablement. The mobility trend is creating a wave of change in the industry and driving transformation in the enterprise. If you're not on that wave, the business risk continues to rise as your competitiveness drops. Aaron is the Vice President of HCM Strategy at Oracle Corporation where he is responsible for researching and identifying emerging trends in the practice of Human Resources and works to deliver industry-leading technology solutions. Other responsibilities include, ownership of Oracle's innovative HCM solutions across JAPAC and enabling organisations to transform and modernise their workforce tools. Follow him on Twitter @aaronjgreen

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Making Those PanelBoxes Behave

- by Duncan Mills

I have a little problem to solve earlier this week - misbehaving <af:panelBox> components... What do I mean by that? Well here's the scenario, I have a page fragment containing a set of panelBoxes arranged vertically. As it happens, they are stamped out in a loop but that does not really matter. What I want to be able to do is to provide the user with a simple UI to close and open all of the panelBoxes in concert. This could also apply to showDetailHeader and similar items with a disclosed attrubute, but in this case it's good old panelBoxes. Ok, so the basic solution to this should be self evident. I can set up a suitable scoped managed bean that the panelBoxes all refer to for their disclosed attribute state. Then the open all / close commandButtons in the UI can simply set the state of that bean for all the panelBoxes to pick up via EL on their disclosed attribute. Sound OK? Well that works basically without a hitch, but turns out that there is a slight problem and this is where the framework is attempting to be a little too helpful. The issue is that is the user manually discloses or hides a panelBox then that will override the value that the EL is setting. So for example. I start the page with all panelBoxes collapsed, all set by the EL state I'm storing on the session I manually disclose panelBox no 1. I press the Expand All button - all works as you would hope and all the panelBoxes are now disclosed, including of course panelBox 1 which I just expanded manually. Finally I press the Collapse All button and everything collapses except that first panelBox that I manually disclosed. The problem is that the component remembers this manual disclosure and that overrides the value provided by the expression. If I change the viewId (navigate away and back) then the panelBox will start to behave again, until of course I touch it again! Now, the more astute amoungst you would think (as I did) Ah, sound like the MDS personalizaton stuff is getting in the way and the solution should simply be to set the dontPersist attribute to disclosed | ALL. Alas this does not fix the issue. After a little noodling on the best way to approach this I came up with a solution that works well, although if you think of an alternative way do let me know. The principle is simple. In the disclosureListener for the panelBox I take a note of the clientID of the panelBox component that has been touched by the user along with the state. This all gets stored in a Map of Booleans in ViewScope which is keyed by clientID and stores the current disclosed state in the Boolean value. The listener looks like this (it's held in a request scope backing bean for the page): public void handlePBDisclosureEvent(DisclosureEvent disclosureEvent) { String clientId = disclosureEvent.getComponent().getClientId(FacesContext.getCurrentInstance()); boolean state = disclosureEvent.isExpanded(); pbState.addTouchedPanelBox(clientId, state); } The pbState variable referenced here is a reference to the bean which will hold the state of the panelBoxes that lives in viewScope (recall that everything is re-set when the viewid is changed so keeping this in viewScope is just fine and cleans things up automatically). The addTouchedPanelBox() method looks like this: public void addTouchedPanelBox(String clientId, boolean state) { //create the cache if needed this is just a Map<String,Boolean> if (_touchedPanelBoxState == null) { _touchedPanelBoxState = new HashMap<String, Boolean>(); } // Simply put / replace _touchedPanelBoxState.put(clientId, state); } So that's the first part, we now have a record of every panelBox that the user has touched. So what do we do when the Collapse All or Expand All buttons are pressed? Here we do some JavaScript magic. Basically for each clientID that we have stored away, we issue a client side disclosure event from JavaScript - just as if the user had gone back and changed it manually. So here's the Collapse All button action: public String CloseAllAction() { submitDiscloseOverride(pbState.getTouchedClientIds(true), false); _uiManager.closeAllBoxes(); return null; } The _uiManager.closeAllBoxes() method is just manipulating the master-state that all of the panelBoxes are bound to using EL. The interesting bit though is the line: submitDiscloseOverride(pbState.getTouchedClientIds(true), false); To break that down, the first part is a call to that viewScoped state holder to ask for a list of clientIDs that need to be "tweaked": public String getTouchedClientIds(boolean targetState) { StringBuilder sb = new StringBuilder(); if (_touchedPanelBoxState != null && _touchedPanelBoxState.size() > 0) { for (Map.Entry<String, Boolean> entry : _touchedPanelBoxState.entrySet()) { if (entry.getValue() == targetState) { if (sb.length() > 0) { sb.append(','); } sb.append(entry.getKey()); } } } return sb.toString(); } You'll notice that this method only processes those panelBoxes that will be in the wrong state and returns those as a comma separated list. This is then processed by the submitDiscloseOverride() method: private void submitDiscloseOverride(String clientIdList, boolean targetDisclosureState) { if (clientIdList != null && clientIdList.length() > 0) { FacesContext fctx = FacesContext.getCurrentInstance(); StringBuilder script = new StringBuilder(); script.append("overrideDiscloseHandler('"); script.append(clientIdList); script.append("',"); script.append(targetDisclosureState); script.append(");"); Service.getRenderKitService(fctx, ExtendedRenderKitService.class).addScript(fctx, script.toString()); } } This method constructs a JavaScript command to call a routine called overrideDiscloseHandler() in a script attached to the page (using the standard <af:resource> tag). That method parses out the list of clientIDs and sends the correct message to each one: function overrideDiscloseHandler(clientIdList, newState) { AdfLogger.LOGGER.logMessage(AdfLogger.INFO, "Disclosure Hander newState " + newState + " Called with: " + clientIdList); //Parse out the list of clientIds var clientIdArray = clientIdList.split(','); for (var i = 0; i < clientIdArray.length; i++){ var panelBox = flipPanel = AdfPage.PAGE.findComponentByAbsoluteId(clientIdArray[i]); if (panelBox.getComponentType() == "oracle.adf.RichPanelBox"){ panelBox.broadcast(new AdfDisclosureEvent(panelBox, newState)); } } } So there you go. You can see how, with a few tweaks the same code could be used for other components with disclosure that might suffer from the same problem, although I'd point out that the behavior I'm working around here us usually desirable. You can download the running example (11.1.2.2) from here.

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Oracle B2B - Synchronous Request Reply

- by cdwright

Introduction So first off, let me say I didn't create this demo (although I did modify it some). I got it from a member of the B2B development technical staff. Since it came with only a simple readme file, I thought I would take some time and write a more detailed explanation about how it works. Beginning with Oracle SOA Suite PS5 (11.1.1.6), B2B supports synchronous request reply over http using the b2b/syncreceiver servlet. I’m attaching the demo to this blog which includes a SOA composite archive that needs to be deployed using JDeveloper, a B2B repository with two agreements that need to be deployed using the B2B console, and a test xml file that gets sent to the b2b/syncreceiver servlet using your favorite SOAP test tool (I'm using Firefox Poster here). You can download the zip file containing the demo here. The demo works by sending the sample xml request file (req.xml) to http://<b2bhost>:8001/b2b/syncreceiver using the SOAP test tool. The syncreceiver servlet keeps the socket connection open between itself and the test tool so that it can synchronously send the reply message back. When B2B receives the inbound request message, it is passed to the SOA composite through the default B2B Fabric binding. A simple reply is created in BPEL and returned to B2B which then sends the message back to the test tool using that same socket connection. I’ll show you the B2B configuration first, then we’ll look at the soa composite. Configuring B2B No additional configuration necessary in order to use the syncreceiver servlet. It is already running when you start SOA. After importing the GC_SyncReqRep.zip repository file into B2B, you’ll have the typical GlobalChips host trading partner and the Acme remote trading partner. Document Management The repository contains two very simple custom XML document definitions called Orders and OrdersResponse. In order to determine the trading partner agreement needed to process the inbound Orders document, you need to know two things about it; what is it and where it came from. So let’s look at how B2B identifies the appropriate document definition for the message. The XSD’s for these two document definitions themselves are not particularly interesting. Whenever you're dealing with custom XML documents, B2B identifies the appropriate document definition for each XML message using an XPath Identification Expression. The expression is entered for each of these document definitions under the document administration tab in the B2B console. The full XPATH expression for the Orders document is //*[local-name()='shiporder']/*[local-name()='shipto']/*[local-name()='name']/text(). You can see this path in the XSD diagram below and how it uniquely identifies this message. The OrdersReponse document is identified in the same way. The XPath expression for it is //*[local-name()='Response']/*[local-name()='Status']/text(). You can see how it’s path differs uniquely identifying the reply from the request. Trading Partner Profile The trading partner profiles are very simple too. For GlobalChips, a generic identifier is being used to identify the sender of the response document using the host trading partner name. For Acme, a generic identifier is also being used to identify the sender of the inbound request using the remote trading partner name. The document types are added for the remote trading partner as usual. So the remote trading partner Acme is the sender of the Orders document, and it is the receiver of the OrdersResponse document. For the remote trading partner only, there needs to be a dummy channel which gets used in the outbound response agreement. The channel is not actually used. It is just a necessary place holder that needs to be there when creating the agreement. Trading Partner Agreement The agreements are equally simple. There is no validation and translation is not an option for a custom XML document type. For the InboundAgreement (request) the document definition is set to OrdersDef. In the Agreement Parameters section the generic identifiers have been added for the host and remote trading partners. That’s all that is needed for the inbound transaction. For the OutboundAgreement (response), the document definition is set to OrdersResponseDef and the generic identifiers for the two trading partners are added. The remote trading partner dummy delivery channel is also added to the agreement. SOA Composite Import the SOA composite archive into JDeveloper as an EJB JAR file. Open the composite and you should have a project that looks like this. In the composite, open the b2bInboundSyncSvc exposed service and advance through the setup wizard. Select your Application Server Connection and advance to the Operations window. Notice here that the B2B binding is set to Receive. It is not set for Synchronous Request Reply. Continue advancing through the wizard as you normally would and select finish at the end. Now open BPELProcess1 in the composite. The BPEL process is set as a Synchronous Request Reply as you can see below. The while loop is there just to give the process something to do. The actual reply message is prepared in the assignResponseValues assignment followed by an Invoke of the B2B binding. Open the replyResponse Invoke and go to the properties tab. You’ll see that the fromTradingPartnerId, toTradingPartner, documentTypeName, and documentProtocolRevision properties have been set. Testing the Configuration To test the configuration, I used Firefox Poster. Enter the URL for the b2b/syncreceiver servlet and browse for the req.xml file that contains the test request message. In the Headers tab, add the property ‘from’ and give it the value ‘Acme’. This is how B2B will know where the message is coming from and it will use that information along with the document type name to find the right trading partner agreement. Now post the message. You should get back a response with a status of ‘200 OK’. That’s all there is to it.

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