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• SOA 11g Technology Adapters – ECID Propagation

  - by Greg Mally

  Overview Many SOA Suite 11g deployments include the use of the technology adapters for various activities including integration with FTP, database, and files to name a few. Although the integrations with these adapters are easy and feature rich, there can be some challenges from the operations perspective. One of these challenges is how to correlate a logical business transaction across SOA component instances. This correlation is typically accomplished via the execution context ID (ECID), but we lose the ECID correlation when the business transaction spans technologies like FTP, database, and files. A new feature has been introduced in the Oracle adapter JCA framework to allow the propagation of the ECID. This feature is available in the forthcoming SOA Suite 11.1.1.7 (PS6). The basic concept of propagating the ECID is to identify somewhere in the payload of the message where the ECID can be stored. Then two Binding Properties, relating to the location of the ECID in the message, are added to either the Exposed Service (left-hand side of composite) or External Reference (right-hand side of composite). This will give the JCA framework enough information to either extract the ECID from or add the ECID to the message. In the scenario of extracting the ECID from the message, the ECID will be used for the new component instance. Where to Put the ECID When trying to determine where to store the ECID in the message, you basically have two options: Add a new optional element to your message schema. Leverage an existing element that is not used in your schema. The best scenario is that you are able to add the optional element to your message since trying to find an unused element will prove difficult in most situations. The schema will be holding the ECID value which looks something like the following: 11d1def534ea1be0:7ae4cac3:13b4455735c:-8000-00000000000002dc Configuring Composite Services/References Now that you have identified where you want the ECID to be stored in the message, the JCA framework needs to have this information as well. The two pieces of information that the framework needs relates to the message schema: The namespace for the element in the message. The XPath to the element in the message. To better understand this, let's look at an example for the following database table: When an Exposed Service is created via the Database Adapter Wizard in the composite, the following schema is created: For this example, the two Binding Properties we add to the ReadRow service in the composite are: <!-- Properties for the binding to propagate the ECID from the database table --> <property name="jca.ecid.nslist" type="xs:string" many="false">  xmlns:ns1="http://xmlns.oracle.com/pcbpel/adapter/db/top/ReadRow"</property> <property name="jca.ecid.xpath" type="xs:string" many="false">  /ns1:EcidPropagationCollection/ns1:EcidPropagation/ns1:ecid</property> Notice that the property called jca.ecid.nslist contains the targetNamespace defined in the schema and the property called jca.ecid.xpath contains the XPath statement to the element. The XPath statement also contains the appropriate namespace prefix (ns1) which is defined in the jca.ecid.nslist property. When the Database Adapter service reads a row from the database, it will retrieve the ECID value from the payload and remove the element from the payload. When the component instance is created, it will be associated with the retrieved ECID and the payload contains everything except the ECID element/value. The only time the ECID is visible is when it is stored safely in the resource technology like the database, a file, or a queue. Simple Database/File/JMS Example This section contains a simplified example of how the ECID can propagate through a database table, a file, and JMS queue. The composite for the example looks like the following: The flow of this example is as follows: Invoke database insert using the insertwithecidbpelprocess_client_ep Service. The InsertWithECIDBPELProcess adds a row to the database via the Database Adapter. The JCA Framework adds the ECID to the message prior to inserting. The ReadRow Service retrieves the record and the JCA Framework extracts the ECID from the message. The ECID element is removed from the message. An instance of ReadRowBPELProcess is created and it is associated with the retried ECID. The ReadRowBPELProcess now writes the record to the file system via the File Adapter. The JCA Framework adds the ECID to the message prior to writing the message to file. The ReadFile Service retrieves the record from the file system and the JCA Framework extracts the ECID from the message. The ECID element is removed from the message. An instance of ReadFileBPELProcess is created and it is associated with the retried ECID. The ReadFileBPELProcess now enqueues the message via the JMS Adapter. The JCA Framework adds the ECID to the message prior to enqueuing the message. The DequeueMessage Service retrieves the record and the JCA Framework extracts the ECID from the message. The ECID element is removed from the message. An instance of DequeueMessageBPELProcess is created and it is associated with the retried ECID. The logical flow ends. When viewing the Flow Trace in the Enterprise Manger, you will now see all the instances correlated via ECID: Please check back here when SOA Suite 11.1.1.7 is released for this example. With the example you can run it yourself and reinforce what has been shared in this blog via a hands-on experience. One final note: the contents of this blog may be included in the official SOA Suite 11.1.1.7 documentation, but you will still need to come here to get the example.

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• Scripting Part 1

  - by rbishop

  Dynamic Scripting is a large topic, so let me get a couple of things out of the way first. If you aren't familiar with JavaScript, I can suggest CodeAcademy's JavaScript series. There are also many other websites and books that cover JavaScript from every possible angle.The second thing we need to deal with is JavaScript as a programming language versus a JavaScript environment running in a web browser. Many books, tutorials, and websites completely blur these two together but they are in fact completely separate. What does this really mean in relation to DRM? Since DRM isn't a web browser, there are no document, window, history, screen, or location objects. There are no events like mousedown or click. Trying to call alert('hello!') in DRM will just cause an error. Those concepts are all related to an HTML document (web page) and are part of the Browser Object Model or Document Object Model. DRM has its own object model that exposes DRM-related objects. In practice, feel free to use those sorts of tutorials or practice within your browser; Many of the concepts are directly translatable to writing scripts in DRM. Just don't try to call document.getElementById in your property definition!I think learning by example tends to work the best, so let's try getting a list of all the unique property values for a given node and its children. var uniqueValues = {}; var childEnumerator = node.GetChildEnumerator(); while(childEnumerator.MoveNext()) { var propValue = childEnumerator.GetCurrent().PropValue("Custom.testpropstr1"); print(propValue); if(propValue != null && propValue != '' && !uniqueValues[propValue]) uniqueValues[propValue] = true; } var result = ''; for(var value in uniqueValues){ result += "Found value " + value + ","; } return result;  Now lets break this down piece by piece. var uniqueValues = {}; This declares a variable and initializes it as a new empty Object. You could also have written var uniqueValues = new Object(); Why use an object here? JavaScript objects can also function as a list of keys and we'll use that later to store each property value as a key on the object. var childEnumerator = node.GetChildEnumerator(); while(childEnumerator.MoveNext()) { This gets an enumerator for the node's children. The enumerator allows us to loop through the children one by one. If we wanted to get a filtered list of children, we would instead use ChildrenWith(). When we reach the end of the child list, the enumerator will return false for MoveNext() and that will stop the loop. var propValue = childEnumerator.GetCurrent().PropValue("Custom.testpropstr1"); print(propValue); if(propValue != null && propValue != '' && !uniqueValues[propValue]) uniqueValues[propValue] = true; } This gets the node the enumerator is currently pointing at, then calls PropValue() on it to get the value of a property. We then make sure the prop value isn't null or the empty string, then we make sure the value doesn't already exist as a key. Assuming it doesn't we add it as a key with a value (true in this case because it makes checking for an existing value faster when the value exists). A quick word on the print() function. When viewing the prop grid, running an export, or performing normal DRM operations it does nothing. If you have a lot of print() calls with complicated arguments it can slow your script down slightly, but otherwise has no effect. But when using the script editor, all the output of print() will be shown in the Warnings area. This gives you an extremely useful debugging tool to see what exactly a script is doing. var result = ''; for(var value in uniqueValues){ result += "Found value " + value + ","; } return result; Now we build a string by looping through all the keys in uniqueValues and adding that value to our string. The last step is to simply return the result. Hopefully this small example demonstrates some of the core Dynamic Scripting concepts. Next time, we can try checking for node references in other hierarchies to see if they are using duplicate property values.

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• Using Transaction Logging to Recover Post-Archived Essbase data

  - by Keith Rosenthal

  Data recovery is typically performed by restoring data from an archive.  Data added or removed since the last archive took place can also be recovered by enabling transaction logging in Essbase.  Transaction logging works by writing transactions to a log store.  The information in the log store can then be recovered by replaying the log store entries in sequence since the last archive took place.  The following information is recorded within a transaction log entry: Sequence ID Username Start Time End Time Request Type A request type can be one of the following categories: Calculations, including the default calculation as well as both server and client side calculations Data loads, including data imports as well as data loaded using a load rule Data clears as well as outline resets Locking and sending data from SmartView and the Spreadsheet Add-In.  Changes from Planning web forms are also tracked since a lock and send operation occurs during this process. You can use the Display Transactions command in the EAS console or the query database MAXL command to view the transaction log entries. Enabling Transaction Logging Transaction logging can be enabled at the Essbase server, application or database level by adding the TRANSACTIONLOGLOCATION essbase.cfg setting.  The following is the TRANSACTIONLOGLOCATION syntax: TRANSACTIONLOGLOCATION [appname [dbname]] LOGLOCATION NATIVE ENABLE | DISABLE Note that you can have multiple TRANSACTIONLOGLOCATION entries in the essbase.cfg file.  For example: TRANSACTIONLOGLOCATION Hyperion/trlog NATIVE ENABLE TRANSACTIONLOGLOCATION Sample Hyperion/trlog NATIVE DISABLE The first statement will enable transaction logging for all Essbase applications, and the second statement will disable transaction logging for the Sample application.  As a result, transaction logging will be enabled for all applications except the Sample application. A location on a physical disk other than the disk where ARBORPATH or the disk files reside is recommended to optimize overall Essbase performance. Configuring Transaction Log Replay Although transaction log entries are stored based on the LOGLOCATION parameter of the TRANSACTIONLOGLOCATION essbase.cfg setting, copies of data load and rules files are stored in the ARBORPATH/app/appname/dbname/Replay directory to optimize the performance of replaying logged transactions.  The default is to archive client data loads, but this configuration setting can be used to archive server data loads (including SQL server data loads) or both client and server data loads. To change the type of data to be archived, add the TRANSACTIONLOGDATALOADARCHIVE configuration setting to the essbase.cfg file.  Note that you can have multiple TRANSACTIONLOGDATALOADARCHIVE entries in the essbase.cfg file to adjust settings for individual applications and databases. Replaying the Transaction Log and Transaction Log Security Considerations To replay the transactions, use either the Replay Transactions command in the EAS console or the alter database MAXL command using the replay transactions grammar.  Transactions can be replayed either after a specified log time or using a range of transaction sequence IDs. The default when replaying transactions is to use the security settings of the user who originally performed the transaction.  However, if that user no longer exists or that user's username was changed, the replay operation will fail. Instead of using the default security setting, add the REPLAYSECURITYOPTION essbase.cfg setting to use the security settings of the administrator who performs the replay operation.  REPLAYSECURITYOPTION 2 will explicitly use the security settings of the administrator performing the replay operation.  REPLAYSECURITYOPTION 3 will use the administrator security settings if the original user’s security settings cannot be used. Removing Transaction Logs and Archived Replay Data Load and Rules Files Transaction logs and archived replay data load and rules files are not automatically removed and are only removed manually.  Since these files can consume a considerable amount of space, the files should be removed on a periodic basis. The transaction logs should be removed one database at a time instead of all databases simultaneously.  The data load and rules files associated with the replayed transactions should be removed in chronological order from earliest to latest.  In addition, do not remove any data load and rules files with a timestamp later than the timestamp of the most recent archive file. Partitioned Database Considerations For partitioned databases, partition commands such as synchronization commands cannot be replayed.  When recovering data, the partition changes must be replayed manually and logged transactions must be replayed in the correct chronological order. If the partitioned database includes any @XREF commands in the calc script, the logged transactions must be selectively replayed in the correct chronological order between the source and target databases. References For additional information, please see the Oracle EPM System Backup and Recovery Guide.  For EPM 11.1.2.2, the link is http://docs.oracle.com/cd/E17236_01/epm.1112/epm_backup_recovery_1112200.pdf

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• Trying to detect collision between two polygons using Separating Axis Theorem

  - by Holly

  The only collision experience i've had was with simple rectangles, i wanted to find something that would allow me to define polygonal areas for collision and have been trying to make sense of SAT using these two links Though i'm a bit iffy with the math for the most part i feel like i understand the theory! Except my implementation somewhere down the line must be off as: (excuse the hideous font) As mentioned above i have defined a CollisionPolygon class where most of my theory is implemented and then have a helper class called Vect which was meant to be for Vectors but has also been used to contain a vertex given that both just have two float values. I've tried stepping through the function and inspecting the values to solve things but given so many axes and vectors and new math to work out as i go i'm struggling to find the erroneous calculation(s) and would really appreciate any help. Apologies if this is not suitable as a question! CollisionPolygon.java: package biz.hireholly.gameplay; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import biz.hireholly.gameplay.Types.Vect; public class CollisionPolygon { Paint paint; private Vect[] vertices; private Vect[] separationAxes; CollisionPolygon(Vect[] vertices){ this.vertices = vertices; //compute edges and separations axes separationAxes = new Vect[vertices.length]; for (int i = 0; i < vertices.length; i++) { // get the current vertex Vect p1 = vertices[i]; // get the next vertex Vect p2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; // subtract the two to get the edge vector Vect edge = p1.subtract(p2); // get either perpendicular vector Vect normal = edge.perp(); // the perp method is just (x, y) => (-y, x) or (y, -x) separationAxes[i] = normal; } paint = new Paint(); paint.setColor(Color.RED); } public void draw(Canvas c, int xPos, int yPos){ for (int i = 0; i < vertices.length; i++) { Vect v1 = vertices[i]; Vect v2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; c.drawLine( xPos + v1.x, yPos + v1.y, xPos + v2.x, yPos + v2.y, paint); } } /* consider changing to a static function */ public boolean intersects(CollisionPolygon p){ // loop over this polygons separation exes for (Vect axis : separationAxes) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // loop over the other polygons separation axes Vect[] sepAxesOther = p.getSeparationAxes(); for (Vect axis : sepAxesOther) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // if we get here then we know that every axis had overlap on it // so we can guarantee an intersection return true; } /* Note projections wont actually be acurate if the axes aren't normalised * but that's not necessary since we just need a boolean return from our * intersects not a Minimum Translation Vector. */ private Vect minMaxProjection(Vect axis) { float min = axis.dot(vertices[0]); float max = min; for (int i = 1; i < vertices.length; i++) { float p = axis.dot(vertices[i]); if (p < min) { min = p; } else if (p > max) { max = p; } } Vect minMaxProj = new Vect(min, max); return minMaxProj; } public Vect[] getSeparationAxes() { return separationAxes; } public Vect[] getVertices() { return vertices; } } Vect.java: package biz.hireholly.gameplay.Types; /* NOTE: Can also be used to hold vertices! Projections, coordinates ect */ public class Vect{ public float x; public float y; public Vect(float x, float y){ this.x = x; this.y = y; } public Vect perp() { return new Vect(-y, x); } public Vect subtract(Vect other) { return new Vect(x - other.x, y - other.y); } public boolean overlap(Vect other) { if( other.x <= y || other.y >= x){ return true; } return false; } /* used specifically for my SAT implementation which i'm figuring out as i go, * references for later.. * http://www.gamedev.net/page/resources/_/technical/game-programming/2d-rotated-rectangle-collision-r2604 * http://www.codezealot.org/archives/55 */ public float scalarDotProjection(Vect other) { //multiplier = dot product / length^2 float multiplier = dot(other) / (x*x + y*y); //to get the x/y of the projection vector multiply by x/y of axis float projX = multiplier * x; float projY = multiplier * y; //we want to return the dot product of the projection, it's meaningless but useful in our SAT case return dot(new Vect(projX,projY)); } public float dot(Vect other){ return (other.x*x + other.y*y); } }

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• Books are Dead! Long Live the Books!

  - by smisner

  We live in interesting times with regard to the availability of technical material. We have lots of free written material online in the form of vendor documentation online, forums, blogs, and Twitter. And we have written material that we can buy in the form of books, magazines, and training materials. Online videos and training – some free and some not free – are also an option. All of these formats are useful for one need or another. As an author, I pay particular attention to the demand for books, and for now I see no reason to stop authoring books. I assure you that I don’t get rich from the effort, and fortunately that is not my motivation. As someone who likes to refer to books frequently, I am still a big believer in books and have evidence from book sales that there are others like me. If I can do my part to help others learn about the technologies I work with, I will continue to produce content in a variety of formats, including books. (You can view a list of all of my books on the Publications page of my site and my online training videos at Pluralsight.) As a consumer of technical information, I prefer books because a book typically can get into a topic much more deeply than a blog post, and can provide more context than vendor documentation. It comes with a table of contents and a (hopefully accurate) index that helps me zero in on a topic of interest, and of course I can use the Search feature in digital form. Some people suggest that technology books are outdated as soon as they get published. I guess it depends on where you are with technology. Not everyone is able to upgrade to the latest and greatest version at release. I do assume, however, that the SQL Server 7.0 titles in my library have little value for me now, but I’m certain that the minute I discard the book, I’m going to want it for some reason! Meanwhile, as electronic books overtake physical books in sales, my husband is grateful that I can continue to build my collection digitally rather than physically as the books have a way of taking over significant square footage in our house! Blog posts, on the other hand, are useful for describing the scenarios that come up in real-life implementations that wouldn’t fit neatly into a book. As many years that I have working with the Microsoft BI stack, I still run into new problems that require creative thinking. Likewise, people who work with BI and other technologies that I use share what they learn through their blogs. Internet search engines help us find information in blogs that simply isn’t available anywhere else. Another great thing about blogs, also, is the connection to community and the dialog that can ensue between people with common interests. With the trend towards electronic formats for books, I imagine that we’ll see books continue to adapt to incorporate different forms of media and better ways to keep the information current. At the moment, I wish I had a better way to help readers with my last two Reporting Services books. In the case of the Microsoft® SQL Server™ 2005 Reporting Services Step by Step book, I have heard many cases of readers having problems with the sample database that shipped on CD – either the database was missing or it was corrupt. So I’ve provided a copy of the database on my site for download from http://datainspirations.com/uploads/rs2005sbsDW.zip. Then for the Microsoft® SQL Server™ 2008 Reporting Services Step by Step book, we decided to avoid the database problem by using the AdventureWorks2008 samples that Microsoft published on Codeplex (although code samples are still available on CD). We had this silly idea that the URL for the download would remain constant, but it seems that expectation was ill-founded. Currently, the sample database is found at http://msftdbprodsamples.codeplex.com/releases/view/37109 but I have no idea how long that will remain valid. My latest books (#9 and #10 which are milestones I never anticipated), Building Integrated Business Intelligence Solutions with SQL Server 2008 R2 and Office 2010 (McGraw Hill, 2011) and Business Intelligence in Microsoft SharePoint 2010 (Microsoft Press, 2011), will not ship with a CD, but will provide all code samples for download at a site maintained by the respective publishers. I expect that the URLs for the downloads for the book will remain valid, but there are lots of references to other sites that can change or disappear over time. Does that mean authors shouldn’t make reference to such sites? Personally, I think the benefits to be gained from including links are greater than the risks of the links becoming invalid at some point. Do you think the time for technology books has come to an end? Is the delivery of books in electronic format enough to keep them alive? If technological barriers were no object, what would make a book more valuable to you than other formats through which you can obtain information?

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• Mobile Apps for Oracle E-Business Suite

  - by Carlos Chang

  Crosspost from the mobile apps blog.  TL;DR Oracle E-Business Suite is now building mobile apps with Oracle Mobile Application Framework (MAF). Believe it! Build iOS and Android apps with once code base and get it done! By Steven Chan (Oracle Development)  Many things have changed in the mobile space over the last few years. Here's an update on our strategy for mobile apps for the E-Business Suite. Mobile app strategy We're building our family of mobile apps for the E-Business Suite using Oracle Mobile Application Framework.  This framework allows us to write a single application that can be run on Apple iOS and Google Android platforms. Mobile apps for the E-Business Suite will share a common look-and-feel. The E-Business Suite is a suite of over 200 product modules spanning Financials, Supply Chain, Human Resources, and many other areas. Our mobile app strategy is to release standalone apps for specific product modules.  Our Oracle Timecards app, which allows users to create and submit timecards, is an example of a standalone app. Some common functions that span multiple product areas will have dedicated apps, too. An example of this is ourOracle Approvals app, which allows users to review and approve requests for expenses, requisitions, purchase orders, recruitment vacancies and offers, and more. You can read more about our Oracle Mobile Approvals app here: Now Available: Oracle Mobile Approvals for iOS Our goal is to support smaller screen (e.g. smartphones) as well as larger screens (e.g. tablets), with the smaller screen versions generally delivered first.  Where possible, we will deliver these as universal apps.  An example is our Oracle Mobile Field Service app, which allows field service technicians to remotely access customer, product, service request, and task-related information.  This app can run on a smartphone, while providing a richer experience for tablets. Deploying EBS mobile apps The mobile apps, themselves (i.e. client-side components) can be downloaded by end-users from the Apple iTunes today.  Android versions will be available from Google play. You can monitor this blog for Android-related updates. Where possible, our mobile apps should be deployable with a minimum of server-side changes.  These changes will generally involve a consolidated server-side patch for technology-stack components, and possibly a server-side patch for the functional product module. Updates to existing mobile apps may require new server-side components to enable all of the latest mobile functionality. All EBS product modules are certified for internal intranet deployments (i.e. used by employees within an organization's firewall).  Only a subset of EBS products such as iRecruitment are certified to be deployed externally (i.e. used by non-employees outside of an organization's firewall).  Today, many organizations running the E-Business Suite do not expose their EBS environment externally and all of the mobile apps that we're building are intended for internal employee use.  Recognizing this, our mobile apps are currently designed for users who are connected to the organization's intranet via VPN.  We expect that this may change in future updates to our mobile apps. Mobile apps and internationalization The initial releases of our mobile apps will be in English.  Later updates will include translations for all left-to-right languages supported by the E-Business Suite.  Right-to-left languages will not be translated. Customizing apps for enterprise deployments The current generation of mobile apps for Oracle E-Business Suite cannot be customized. We are evaluating options for limited customizations, including corporate branding with logos, corporate color schemes, and others. This is a potentially-complex area with many tricky implications for deployment and maintenance.  We would be interested in hearing your requirements for customizations in enterprise deployments.Prerequisites Apple iOS 7 and higher Android 4.1 (API level 16) and higher, with minimum CPU/memory configurations listed here EBS 12.1: EBS 12.1.3 Family Packs for the related product module EBS 12.2.3 References Oracle E-Business Suite Mobile Apps, Release 12.1 and 12.2 Documentation (Note 1641772.1) Oracle E-Business Suite Mobile Apps Administrator's Guide, Release 12.1 and 12.2 (Note 1642431.1) Follow @OracleMobile on Twitter Oracle Mobile Blog is here. 

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• Composing Silverlight Applications With MEF

  - by PeterTweed

  Anyone who has written an application with complexity enough to warrant multiple controls on multiple pages/forms should understand the benefit of composite application development.  That is defining your application architecture that can be separated into separate pieces each with it’s own distinct purpose that can then be “composed” together into the solution. Composition can be useful in any layer of the application, from the presentation layer, the business layer, common services or data access.  Historically people have had different options to achieve composing applications from distinct well known pieces – their own version of dependency injection, containers to aid with composition like Unity, the composite application guidance for WPF and Silverlight and before that the composite application block. Microsoft has been working on another mechanism to aid composition and extension of applications for some time now – the Managed Extensibility Framework or MEF for short.  With Silverlight 4 it is part of the Silverlight environment.  MEF allows a much simplified mechanism for composition and extensibility compared to other mechanisms – which has always been the primary issue for adoption of the earlier mechanisms/frameworks. This post will guide you through the simple use of MEF for the scenario of composition of an application – using exports, imports and composition.  Steps: 1.     Create a new Silverlight 4 application. 2.     Add references to the following assemblies: System.ComponentModel.Composition.dll System.ComponentModel.Composition.Initialization.dll 3.     Add a new user control called LeftControl. 4.     Replace the LayoutRoot Grid with the following xaml:     <Grid x:Name="LayoutRoot" Background="Beige" Margin="40" >         <Button Content="Left Content" Margin="30"></Button>     </Grid> 5.     Add the following statement to the top of the LeftControl.xaml.cs file using System.ComponentModel.Composition; 6.     Add the following attribute to the LeftControl class     [Export(typeof(LeftControl))]   This attribute tells MEF that the type LeftControl will be exported – i.e. made available for other applications to import and compose into the application. 7.     Add a new user control called RightControl. 8.     Replace the LayoutRoot Grid with the following xaml:     <Grid x:Name="LayoutRoot" Background="Green" Margin="40"  >         <TextBlock Margin="40" Foreground="White" Text="Right Control" FontSize="16" VerticalAlignment="Center" HorizontalAlignment="Center" ></TextBlock>     </Grid> 9.     Add the following statement to the top of the RightControl.xaml.cs file using System.ComponentModel.Composition; 10.   Add the following attribute to the RightControl class     [Export(typeof(RightControl))] 11.   Add the following xaml to the LayoutRoot Grid in MainPage.xaml:         <StackPanel Orientation="Horizontal" HorizontalAlignment="Center">             <Border Name="LeftContent" Background="Red" BorderBrush="Gray" CornerRadius="20"></Border>             <Border Name="RightContent" Background="Red" BorderBrush="Gray" CornerRadius="20"></Border>         </StackPanel>   The borders will hold the controls that will be imported and composed via MEF. 12.   Add the following statement to the top of the MainPage.xaml.cs file using System.ComponentModel.Composition; 13.   Add the following properties to the MainPage class:         [Import(typeof(LeftControl))]         public LeftControl LeftUserControl { get; set; }         [Import(typeof(RightControl))]         public RightControl RightUserControl { get; set; }   This defines properties accepting LeftControl and RightControl types.  The attrributes are used to tell MEF the discovered type that should be applied to the property when composition occurs. 14.   Replace the MainPage constructore with the following code:         public MainPage()         {             InitializeComponent();             CompositionInitializer.SatisfyImports(this);             LeftContent.Child = LeftUserControl;             RightContent.Child = RightUserControl;         }   The CompositionInitializer.SatisfyImports(this) function call tells MEF to discover types related to the declared imports for this object (the MainPage object).  At that point, types matching those specified in the import defintions are discovered in the executing assembly location of the application and instantiated and assigned to the matching properties of the current object. 15.   Run the application and you will see the left control and right control types displayed in the MainPage:   Congratulations!  You have used MEF to dynamically compose user controls into a parent control in a composite application model. In the next post we will build on this topic to cover using MEF to compose Silverlight applications dynamically in download on demand scenarios – so .xap packages can be downloaded only when needed, avoiding large initial download for the main application xap. Take the Slalom Challenge at www.slalomchallenge.com!

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• ROracle support for TimesTen In-Memory Database

  - by Sam Drake

  Today's guest post comes from Jason Feldhaus, a Consulting Member of Technical Staff in the TimesTen Database organization at Oracle.  He shares with us a sample session using ROracle with the TimesTen In-Memory database.  Beginning in version 1.1-4, ROracle includes support for the Oracle Times Ten In-Memory Database, version 11.2.2. TimesTen is a relational database providing very fast and high throughput through its memory-centric architecture.  TimesTen is designed for low latency, high-volume data, and event and transaction management. A TimesTen database resides entirely in memory, so no disk I/O is required for transactions and query operations. TimesTen is used in applications requiring very fast and predictable response time, such as real-time financial services trading applications and large web applications. TimesTen can be used as the database of record or as a relational cache database to Oracle Database. ROracle provides an interface between R and the database, providing the rich functionality of the R statistical programming environment using the SQL query language. ROracle uses the OCI libraries to handle database connections, providing much better performance than standard ODBC.The latest ROracle enhancements include: Support for Oracle TimesTen In-Memory Database Support for Date-Time using R's POSIXct/POSIXlt data types RAW, BLOB and BFILE data type support Option to specify number of rows per fetch operation Option to prefetch LOB data Break support using Ctrl-C Statement caching support Times Ten 11.2.2 contains enhanced support for analytics workloads and complex queries: Analytic functions: AVG, SUM, COUNT, MAX, MIN, DENSE_RANK, RANK, ROW_NUMBER, FIRST_VALUE and LAST_VALUE Analytic clauses: OVER PARTITION BY and OVER ORDER BY Multidimensional grouping operators: Grouping clauses: GROUP BY CUBE, GROUP BY ROLLUP, GROUP BY GROUPING SETS Grouping functions: GROUP, GROUPING_ID, GROUP_ID WITH clause, which allows repeated references to a named subquery block Aggregate expressions over DISTINCT expressions General expressions that return a character string in the source or a pattern within the LIKE predicate Ability to order nulls first or last in a sort result (NULLS FIRST or NULLS LAST in the ORDER BY clause) Note: Some functionality is only available with Oracle Exalytics, refer to the TimesTen product licensing document for details. Connecting to TimesTen is easy with ROracle. Simply install and load the ROracle package and load the driver. > install.packages("ROracle") > library(ROracle) Loading required package: DBI > drv <- dbDriver("Oracle") Once the ROracle package is installed, create a database connection object and connect to a TimesTen direct driver DSN as the OS user. > conn <- dbConnect(drv, username ="", password="", dbname = "localhost/SampleDb_1122:timesten_direct") You have the option to report the server type - Oracle or TimesTen? > print (paste ("Server type =", dbGetInfo (conn)$serverType)) [1] "Server type = TimesTen IMDB" To create tables in the database using R data frame objects, use the function dbWriteTable. In the following example we write the built-in iris data frame to TimesTen. The iris data set is a small example data set containing 150 rows and 5 columns. We include it here not to highlight performance, but so users can easily run this example in their R session. > dbWriteTable (conn, "IRIS", iris, overwrite=TRUE, ora.number=FALSE) [1] TRUE Verify that the newly created IRIS table is available in the database. To list the available tables and table columns in the database, use dbListTables and dbListFields, respectively. > dbListTables (conn) [1] "IRIS" > dbListFields (conn, "IRIS") [1] "SEPAL.LENGTH" "SEPAL.WIDTH" "PETAL.LENGTH" "PETAL.WIDTH" "SPECIES" To retrieve a summary of the data from the database we need to save the results to a local object. The following call saves the results of the query as a local R object, iris.summary. The ROracle function dbGetQuery is used to execute an arbitrary SQL statement against the database. When connected to TimesTen, the SQL statement is processed completely within main memory for the fastest response time. > iris.summary <- dbGetQuery(conn, 'SELECT SPECIES, AVG ("SEPAL.LENGTH") AS AVG_SLENGTH, AVG ("SEPAL.WIDTH") AS AVG_SWIDTH, AVG ("PETAL.LENGTH") AS AVG_PLENGTH, AVG ("PETAL.WIDTH") AS AVG_PWIDTH FROM IRIS GROUP BY ROLLUP (SPECIES)') > iris.summary SPECIES AVG_SLENGTH AVG_SWIDTH AVG_PLENGTH AVG_PWIDTH 1 setosa 5.006000 3.428000 1.462 0.246000 2 versicolor 5.936000 2.770000 4.260 1.326000 3 virginica 6.588000 2.974000 5.552 2.026000 4 <NA> 5.843333 3.057333 3.758 1.199333 Finally, disconnect from the TimesTen Database. > dbCommit (conn) [1] TRUE > dbDisconnect (conn) [1] TRUE We encourage you download Oracle software for evaluation from the Oracle Technology Network. See these links for our software: Times Ten In-Memory Database,  ROracle.  As always, we welcome comments and questions on the TimesTen and  Oracle R technical forums.

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• Building a plug-in for Windows Live Writer

  - by mbcrump

  This tutorial will show you how to build a plug-in for Windows Live Writer. Windows Live Writer is a blogging tool that Microsoft provides for free. It includes an open API for .NET developers to create custom plug-ins. In this tutorial, I will show you how easy it is to build one. Open VS2008 or VS2010 and create a new project. Set the target framework to 2.0, Application Type to Class Library and give it a name. In this tutorial, we are going to create a plug-in that generates a twitter message with your blog post name and a TinyUrl link to the blog post.  It will do all of this automatically after you publish your post. Once, we have a new projected created. We need to setup the references. Add a reference to the WindowsLive.Writer.Api.dll located in the C:\Program Files (x86)\Windows Live\Writer\ folder, if you are using X64 version of Windows. You will also need to add a reference to System.Windows.Forms System.Web from the .NET tab as well. Once that is complete, add your “using” statements so that it looks like whats shown below: Live Writer Plug-In "Using" using System; using System.Collections.Generic; using System.Text; using WindowsLive.Writer.Api; using System.Web; Now, we are going to setup some build events to make it easier to test our custom class. Go into the Properties of your project and select Build Events, click edit the Post-build and copy/paste the following line: XCOPY /D /Y /R "$(TargetPath)" "C:\Program Files (x86)\Windows Live\Writer\Plugins\" Your screen should look like the one pictured below: Next, we are going to launch an external program on debug. Click the debug tab and enter C:\Program Files (x86)\Windows Live\Writer\WindowsLiveWriter.exe Your screen should look like the one pictured below:   Now we have a blank project and we need to add some code. We start with adding the attributes for the Live Writer Plugin. Before we get started creating the Attributes, we need to create a GUID. This GUID will uniquely identity our plug-in. So, to create a GUID follow the steps in VS2008/2010. Click Tools from the VS Menu ->Create GUID It will generate a GUID like the one listed below: GUID <Guid("56ED8A2C-F216-420D-91A1-F7541495DBDA")> We only want what’s inside the quotes, so your final product should be: "56ED8A2C-F216-420D-91A1-F7541495DBDA". Go ahead and paste this snipped into your class just above the public class. Live Writer Plug-In Attributes [WriterPlugin("56ED8A2C-F216-420D-91A1-F7541495DBDA",    "Generate Twitter Message",    Description = "After your new post has been published, this plug-in will attempt to generate a Twitter status messsage with the Title and TinyUrl link.",    HasEditableOptions = false,    Name = "Generate Twitter Message",    PublisherUrl = "http://michaelcrump.net")] [InsertableContentSource("Generate Twitter Message")] So far, it should look like the following: Next, we need to implement the PublishNotifcationHook class and override the OnPostPublish. I’m not going to dive into what the code is doing as you should be able to follow pretty easily. The code below is the entire code used in the project. PublishNotificationHook public class Class1 :  PublishNotificationHook  {      public override void OnPostPublish(System.Windows.Forms.IWin32Window dialogOwner, IProperties properties, IPublishingContext publishingContext, bool publish)      {          if (!publish) return;          if (string.IsNullOrEmpty(publishingContext.PostInfo.Permalink))          {              PluginDiagnostics.LogError("Live Tweet didn't execute, due to blank permalink");          }          else          {                var strBlogName = HttpUtility.UrlEncode("#blogged : " + publishingContext.PostInfo.Title);  //Blog Post Title              var strUrlFinal = getTinyUrl(publishingContext.PostInfo.Permalink); //Blog Permalink URL Converted to TinyURL              System.Diagnostics.Process.Start("http://twitter.com/home?status=" + strBlogName + strUrlFinal);            }      } We are going to go ahead and create a method to create the short url (tinyurl). TinyURL Helper Method private static string getTinyUrl(string url) {     var cmpUrl = System.Globalization.CultureInfo.InvariantCulture.CompareInfo;     if (!cmpUrl.IsPrefix(url, "http://tinyurl.com"))     {         var address = "http://tinyurl.com/api-create.php?url=" + url;         var client = new System.Net.WebClient();         return (client.DownloadString(address));     }     return (url); } Go ahead and build your project, it should have copied the .DLL into the Windows Live Writer Plugin Directory. If it did not, then you will want to check your configuration. Once that is complete, open Windows Live Writer and select Tools-> Options-> Plug-ins and enable your plug-in that you just created. Your screen should look like the one pictured below: Go ahead and click OK and publish your blog post. You should get a pop-up with the following: Hit OK and It should open a Twitter and either ask for a login or fill in your status as shown below:   That should do it, you can do so many other things with the API. I suggest that if you want to build something really useful consult the MSDN pages. This plug-in that I created was perfect for what I needed and I hope someone finds it useful.

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• java.util.zip.ZipException: Error opening file When Deploying an Application to Weblogic Server

  - by lmestre

  The latest weeks we had a hard time trying to solve a deployment issue.* WebLogic Server 10.3.6* Target: WLS Cluster<21-10-2013 05:29:40 PM CLST> <Error> <Console> <BEA-240003> <Console encountered the following error weblogic.management.DeploymentException:        at weblogic.servlet.internal.WarDeploymentFactory.findOrCreateComponentMBeans(WarDeploymentFactory.java:69)        at weblogic.application.internal.MBeanFactoryImpl.findOrCreateComponentMBeans(MBeanFactoryImpl.java:48)        at weblogic.application.internal.MBeanFactoryImpl.createComponentMBeans(MBeanFactoryImpl.java:110)        at weblogic.application.internal.MBeanFactoryImpl.initializeMBeans(MBeanFactoryImpl.java:76)        at weblogic.management.deploy.internal.MBeanConverter.createApplicationMBean(MBeanConverter.java:89)        at weblogic.management.deploy.internal.MBeanConverter.createApplicationForAppDeployment(MBeanConverter.java:67)        at weblogic.management.deploy.internal.MBeanConverter.setupNew81MBean(MBeanConverter.java:315)        at weblogic.deploy.internal.targetserver.operations.ActivateOperation.compatibilityProcessor(ActivateOperation.java:81)        at weblogic.deploy.internal.targetserver.operations.AbstractOperation.setupPrepare(AbstractOperation.java:295)        at weblogic.deploy.internal.targetserver.operations.ActivateOperation.doPrepare(ActivateOperation.java:97)        at weblogic.deploy.internal.targetserver.operations.AbstractOperation.prepare(AbstractOperation.java:217)        at weblogic.deploy.internal.targetserver.DeploymentManager.handleDeploymentPrepare(DeploymentManager.java:747)        at weblogic.deploy.internal.targetserver.DeploymentManager.prepareDeploymentList(DeploymentManager.java:1216)        at weblogic.deploy.internal.targetserver.DeploymentManager.handlePrepare(DeploymentManager.java:250)        at weblogic.deploy.internal.targetserver.DeploymentServiceDispatcher.prepare(DeploymentServiceDispatcher.java:159)        at weblogic.deploy.service.internal.targetserver.DeploymentReceiverCallbackDeliverer.doPrepareCallback(DeploymentReceiverCallbackDeliverer.java:171)        at weblogic.deploy.service.internal.targetserver.DeploymentReceiverCallbackDeliverer.access$000(DeploymentReceiverCallbackDeliverer.java:13)        at weblogic.deploy.service.internal.targetserver.DeploymentReceiverCallbackDeliverer$1.run(DeploymentReceiverCallbackDeliverer.java:46)        at weblogic.work.SelfTuningWorkManagerImpl$WorkAdapterImpl.run(SelfTuningWorkManagerImpl.java:545)        at weblogic.work.ExecuteThread.execute(ExecuteThread.java:256)        at weblogic.work.ExecuteThread.run(ExecuteThread.java:221)Caused by: java.util.zip.ZipException: Error opening file - C:\Oracle\Middleware\user_projects\domains\MyDomain\servers\MyServer\stage\myapp\myapp.war Message - error in opening zip file        at weblogic.servlet.utils.WarUtils.existsInWar(WarUtils.java:87)        at weblogic.servlet.utils.WarUtils.isWebServices(WarUtils.java:76)        at weblogic.servlet.internal.WarDeploymentFactory.findOrCreateComponentMBeans(WarDeploymentFactory.java:61) So the first idea you have with that error is that the war file is corrupted or has incorrect privileges.        We tried:1. Unzipping the  war file, the file was perfect.2. Checking the size, same size as in other environments.3. Checking the ownership of the file, same as in other environments.4. Checking the permissions of the file, same as other applications.Then we accepted the file was fine, so we tried enabling some deployment debugs, but no clues.We also tried:1. Delete all contents of <MyDomain/servers/<MyServer>/tmp> a and <MyDomain/servers/<MyServer>/cache> folders, the issue persisted.2. When renaming the application the deployment was sucessful3. When targeting to the Admin Server, deployment was also working.4. Using 'Copy this application onto every target for me' didn't help either.Finally, my friend 'Test Case' solved the issue again.I saw this name in the config.xml<jdbc-system-resource>    <name>myapp</name>    <target></target>    <descriptor-file-name>jdbc/myapp-jdbc.xml</descriptor-file-name>  </jdbc-system-resource> So, it turned out that customer had created a DataSource with the same name as the application 'myapp' in the above example.By deleting the datasource and created another exact DataSource with a different name the issue was solved.At this point, Do you know Why 'java.util.zip.ZipException: Error opening file' was occurring?Because all names is WebLogic Server need to be unique.References: http://docs.oracle.com/cd/E23943_01/web.1111/e13709/setup.htm"Assigning Names to WebLogic Server ResourcesMake sure that each configurable resource in your WebLogic Server environment has a unique name. Each, domain, server, machine, cluster, JDBC data source, virtual host, or other resource must have a unique name." Enjoy!

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• Error in my Separating Axis Theorem collision code

  - by Holly

  The only collision experience i've had was with simple rectangles, i wanted to find something that would allow me to define polygonal areas for collision and have been trying to make sense of SAT using these two links Though i'm a bit iffy with the math for the most part i feel like i understand the theory! Except my implementation somewhere down the line must be off as: (excuse the hideous font) As mentioned above i have defined a CollisionPolygon class where most of my theory is implemented and then have a helper class called Vect which was meant to be for Vectors but has also been used to contain a vertex given that both just have two float values. I've tried stepping through the function and inspecting the values to solve things but given so many axes and vectors and new math to work out as i go i'm struggling to find the erroneous calculation(s) and would really appreciate any help. Apologies if this is not suitable as a question! CollisionPolygon.java: package biz.hireholly.gameplay; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import biz.hireholly.gameplay.Types.Vect; public class CollisionPolygon { Paint paint; private Vect[] vertices; private Vect[] separationAxes; int x; int y; CollisionPolygon(Vect[] vertices){ this.vertices = vertices; //compute edges and separations axes separationAxes = new Vect[vertices.length]; for (int i = 0; i < vertices.length; i++) { // get the current vertex Vect p1 = vertices[i]; // get the next vertex Vect p2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; // subtract the two to get the edge vector Vect edge = p1.subtract(p2); // get either perpendicular vector Vect normal = edge.perp(); // the perp method is just (x, y) => (-y, x) or (y, -x) separationAxes[i] = normal; } paint = new Paint(); paint.setColor(Color.RED); } public void draw(Canvas c, int xPos, int yPos){ for (int i = 0; i < vertices.length; i++) { Vect v1 = vertices[i]; Vect v2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; c.drawLine( xPos + v1.x, yPos + v1.y, xPos + v2.x, yPos + v2.y, paint); } } public void update(int xPos, int yPos){ x = xPos; y = yPos; } /* consider changing to a static function */ public boolean intersects(CollisionPolygon p){ // loop over this polygons separation exes for (Vect axis : separationAxes) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // loop over the other polygons separation axes Vect[] sepAxesOther = p.getSeparationAxes(); for (Vect axis : sepAxesOther) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // if we get here then we know that every axis had overlap on it // so we can guarantee an intersection return true; } /* Note projections wont actually be acurate if the axes aren't normalised * but that's not necessary since we just need a boolean return from our * intersects not a Minimum Translation Vector. */ private Vect minMaxProjection(Vect axis) { float min = axis.dot(new Vect(vertices[0].x+x, vertices[0].y+y)); float max = min; for (int i = 1; i < vertices.length; i++) { float p = axis.dot(new Vect(vertices[i].x+x, vertices[i].y+y)); if (p < min) { min = p; } else if (p > max) { max = p; } } Vect minMaxProj = new Vect(min, max); return minMaxProj; } public Vect[] getSeparationAxes() { return separationAxes; } public Vect[] getVertices() { return vertices; } } Vect.java: package biz.hireholly.gameplay.Types; /* NOTE: Can also be used to hold vertices! Projections, coordinates ect */ public class Vect{ public float x; public float y; public Vect(float x, float y){ this.x = x; this.y = y; } public Vect perp() { return new Vect(-y, x); } public Vect subtract(Vect other) { return new Vect(x - other.x, y - other.y); } public boolean overlap(Vect other) { if(y > other.x && other.y > x){ return true; } return false; } /* used specifically for my SAT implementation which i'm figuring out as i go, * references for later.. * http://www.gamedev.net/page/resources/_/technical/game-programming/2d-rotated-rectangle-collision-r2604 * http://www.codezealot.org/archives/55 */ public float scalarDotProjection(Vect other) { //multiplier = dot product / length^2 float multiplier = dot(other) / (x*x + y*y); //to get the x/y of the projection vector multiply by x/y of axis float projX = multiplier * x; float projY = multiplier * y; //we want to return the dot product of the projection, it's meaningless but useful in our SAT case return dot(new Vect(projX,projY)); } public float dot(Vect other){ return (other.x*x + other.y*y); } }

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• Creating ADF Faces Comamnd Button at Runtime

  - by Frank Nimphius

  Normal 0 false false false EN-US X-NONE X-NONE /* 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;} In ADF Faces, the command button is an instance of RichCommandButton and can be created at runtime. While creating the button is not difficult at all, adding behavior to it requires knowing about how to dynamically create and add an action listener reference. The example code below shows two methods: The first method, handleButtonPress is a public method exposed on a managed bean. public void handleButtonPress(ActionEvent event){   System.out.println("Event handled");   //optional: partially refresh changed components if command   //issued as a partial submit } The second method is called in response to a user interaction or on page load and dynamically creates and adds a command button. When the button is pressed, the managed bean method – the action handler – defined above is called. The action handler is referenced using EL in the created MethodExpression instance. If the managed bean is in viewScope, backingBeanScope or pageFlowsScope, then you need to add these scopes as a prefix to the EL (as you would when configuring the managed bean reference at design time) //Create command button and add it as a child to the parent component that is passed as an //argument to this method private void reateCommandButton(UIComponent parent){   RichCommandButton edit = new RichCommandButton();   //make the request partial   edit.setPartialSubmit(true);   edit.setText("Edit");                             //compose the method expression to invoke the event handler   FacesContext fctx = FacesContext.getCurrentInstance();   Application application = fctx.getApplication();   ExpressionFactory elFactory = application.getExpressionFactory();   ELContext elContext = facesCtx.getELContext();   MethodExpression methodExpressio = null;   //Make sure the EL expression references a valid managed bean method. Ensure   //the bean scope is properly addressed    methodExpression =  elFactory.createMethodExpression(                              elContext,"#{myRequestScopeBean.handleButtonPress}",                             Object.class,new Class[] {ActionEvent.class});   //Create the command buttonaction listener reference   MethodExpressionActionListener al = null;          al= new MethodExpressionActionListener(methodExpression);    edit.addActionListener(al);     //add new command button to parent component and PPR the component for     //the button to show    parent.getChildren().add(edit);    AdfFacesContext adfFacesContext = AdfFacesContext.getCurrentInstance();     adfFacesContext.addPartialTarget(parent);  }

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• Is Data Science “Science”?

  - by BuckWoody

  I hold the term “science” in very high esteem. I grew up on the Space Coast in Florida, and eventually worked at the Kennedy Space Center, surrounded by very intelligent people who worked in various scientific fields. Recently a new term has entered the computing dialog – “Data Scientist”. Since it’s not a standard term, it has a lot of definitions, and in fact has been disputed as a correct term. After all, the reasoning goes, if there’s no such thing as “Data Science” then how can there be a Data Scientist? This argument has been made before, albeit with a different term – “Computer Science”. In Peter Denning’s excellent article “Is Computer Science Science” (April  2005/Vol. 48, No. 4 COMMUNICATIONS OF THE ACM) there are many points that separate “science” from “engineering” and even “art”.  I won’t repeat the content of that article here (I recommend you read it on your own) but will leverage the points he makes there. Definition of Science To ask the question “is data science ‘science’” then we need to start with a definition of terms. Various references put the definition into the same basic areas: Study of the physical world Systematic and/or disciplined study of a subject area ...and then they include the things studied, the bodies of knowledge and so on. The word itself comes from Latin, and means merely “to know” or “to study to know”. Greek divides knowledge further into “truth” (episteme), and practical use or effects (tekhne). Normally computing falls into the second realm. Definition of Data Science And now a more controversial definition: Data Science. This term is so new and perhaps so niche that the major dictionaries haven’t yet picked it up (my OED reference is older – can’t afford to pop for the online registration at present). Researching the term's general use I created an amalgam of the definitions this way: “Studying and applying mathematical and other techniques to derive information from complex data sets.” Using this definition, data science certainly seems to be science - it's learning about and studying some object or area using systematic methods. But implicit within the definition is the word “application”, which makes the process more akin to engineering or even technology than science. In fact, I find that using these techniques – and data itself – part of science, not science itself. I leave out the concept of studying data patterns or algorithms as part of this discipline. That is actually a domain I see within research, mathematics or computer science. That of course is a type of science, but does not seek for practical applications. As part of the argument against calling it “Data Science”, some point to the scientific method of creating a hypothesis, testing with controls, testing results against the hypothesis, and documenting for repeatability.  These are not steps that we often take in working with data. We normally start with a question, and fit patterns and algorithms to predict outcomes and find correlations. In this way Data Science is more akin to statistics (and in fact makes heavy use of them) in the process rather than starting with an assumption and following on with it. So, is Data Science “Science”? I’m uncertain – and I’m uncertain it matters. Even if we are facing rampant “title inflation” these days (does anyone introduce themselves as a secretary or supervisor anymore?) I can tolerate the term at least from the intent that we use data to study problems across a wide spectrum, rather than restricting it to a single domain. And I also understand those who have worked hard to achieve the very honorable title of “scientist” who have issues with those who borrow the term without asking. What do you think? Science, or not? Does it matter?

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• How customers view and interact with a company

  The Harvard Business Review article written by Rayport and Jaworski is aptly titled “Best Face Forward” because it sheds light on how customers view and interact with a company. In the past most business interaction between customers was performed in a face to face meeting where one party would present an item for sale and then the other would decide whether to purchase the item. In addition, if there was a problem with a purchased item then they would bring the item back to the person who sold the item for resolution. One of my earliest examples of witnessing this was when I was around 6 or 7 years old and I was allowed to spend the summer in Tennessee with my Grandparents. My Grandfather had just written a book about the local history of his town and was selling them to his friends and local bookstores. I still remember he offered to pay me a small commission for every book I helped him sell because I was carrying the books around for him. Every sale he made was face to face with his customers which allowed him to share his excitement for the book with everyone. In today’s modern world there is less and less human interaction as the use of computers and other technologies allow us to communicate within seconds even though both parties may be across the globe or just next door. That being said, customers view a company through multiple access points called faces that represent the ability to interact without actually seeing a human face. As a software engineer this is a good and a bad thing because direct human interaction and technology based interaction have both good and bad attributes based on the customer. How organizations coordinate business and IT functions, to provide quality service varies based on each individual business and the goals and directives put in place by its management. According to Rayport and Jaworski, the type of interaction used through a particular access point may lend itself to be people-dominate, machine-dominate, or a combination of both. The method by which a company communicates information through an access point is a strategic choice that relates costs and customer outcomes. To simplify this, the choice is based on what can give the customer the best experience interacting with the company when the cost of the interaction is also a factor. I personally see examples of this every day at work. The company website is machine-dominate with people updating and maintaining information, our groups department is people dominate because most of the customer interaction is done at the customers location and is backed up by machine based data sources, and our sales/member service department is a hybrid because employees work in tandem with machines in order for them to assist customers with signing up or any other issue they may have. The positive and negative aspects of human and machine interfaces are a key aspect in deciding which interface to use when allowing customers to access a company or a combination of the two. Rayport and Jaworski also used MIT professor Erik Brynjolfsson preliminary catalog of human and machine strengths. He stated that humans outperform machines in judgment, pattern recognition, exception processing, insight, and creativity. I have found this to be true based on the example of how sales and member service reps at my company handle a multitude of questions and various situations with a lot of unknown variables. A machine interface could never effectively be able to handle these scenarios because there are too many variables to consider and would not have the built-in logic to process each customer’s claims and needs. In addition, he also stated that machines outperform humans in collecting, storing, transmitting and routine processing. An example of this would be my employer’s website. Customers can simply go online and purchase a product without even talking to a sales or member services representative. The information is then stored in a database so that the customer can always go back and review there order, and access their selected services. A human, no matter how smart they are would never be able to keep track of hundreds of thousands of customers let alone know what they purchased or how much they paid. In today’s technology driven economy every company must offer their customers multiple methods of accessibly in order to survive. The more of an opportunity a company has to create a positive experience for their customers, in my opinion, they more likely the customer will return to that company again. I have noticed this with my personal shopping habits and experiences. References Rayport, J., & Jaworski, B. (2004). Best Face Forward. Harvard Business Review, 82(12), 47-58. Retrieved from Business Source Complete database.

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• ROracle support for TimesTen In-Memory Database

  - by Sherry LaMonica

  Today's guest post comes from Jason Feldhaus, a Consulting Member of Technical Staff in the TimesTen Database organization at Oracle.  He shares with us a sample session using ROracle with the TimesTen In-Memory database.  Beginning in version 1.1-4, ROracle includes support for the Oracle Times Ten In-Memory Database, version 11.2.2. TimesTen is a relational database providing very fast and high throughput through its memory-centric architecture.  TimesTen is designed for low latency, high-volume data, and event and transaction management. A TimesTen database resides entirely in memory, so no disk I/O is required for transactions and query operations. TimesTen is used in applications requiring very fast and predictable response time, such as real-time financial services trading applications and large web applications. TimesTen can be used as the database of record or as a relational cache database to Oracle Database. ROracle provides an interface between R and the database, providing the rich functionality of the R statistical programming environment using the SQL query language. ROracle uses the OCI libraries to handle database connections, providing much better performance than standard ODBC.The latest ROracle enhancements include: Support for Oracle TimesTen In-Memory Database Support for Date-Time using R's POSIXct/POSIXlt data types RAW, BLOB and BFILE data type support Option to specify number of rows per fetch operation Option to prefetch LOB data Break support using Ctrl-C Statement caching support Times Ten 11.2.2 contains enhanced support for analytics workloads and complex queries: Analytic functions: AVG, SUM, COUNT, MAX, MIN, DENSE_RANK, RANK, ROW_NUMBER, FIRST_VALUE and LAST_VALUE Analytic clauses: OVER PARTITION BY and OVER ORDER BY Multidimensional grouping operators: Grouping clauses: GROUP BY CUBE, GROUP BY ROLLUP, GROUP BY GROUPING SETS Grouping functions: GROUP, GROUPING_ID, GROUP_ID WITH clause, which allows repeated references to a named subquery block Aggregate expressions over DISTINCT expressions General expressions that return a character string in the source or a pattern within the LIKE predicate Ability to order nulls first or last in a sort result (NULLS FIRST or NULLS LAST in the ORDER BY clause) Note: Some functionality is only available with Oracle Exalytics, refer to the TimesTen product licensing document for details. Connecting to TimesTen is easy with ROracle. Simply install and load the ROracle package and load the driver. > install.packages("ROracle") > library(ROracle) Loading required package: DBI > drv <- dbDriver("Oracle") Once the ROracle package is installed, create a database connection object and connect to a TimesTen direct driver DSN as the OS user. > conn <- dbConnect(drv, username ="", password="", dbname = "localhost/SampleDb_1122:timesten_direct") You have the option to report the server type - Oracle or TimesTen? > print (paste ("Server type =", dbGetInfo (conn)$serverType)) [1] "Server type = TimesTen IMDB" To create tables in the database using R data frame objects, use the function dbWriteTable. In the following example we write the built-in iris data frame to TimesTen. The iris data set is a small example data set containing 150 rows and 5 columns. We include it here not to highlight performance, but so users can easily run this example in their R session. > dbWriteTable (conn, "IRIS", iris, overwrite=TRUE, ora.number=FALSE) [1] TRUE Verify that the newly created IRIS table is available in the database. To list the available tables and table columns in the database, use dbListTables and dbListFields, respectively. > dbListTables (conn) [1] "IRIS" > dbListFields (conn, "IRIS") [1] "SEPAL.LENGTH" "SEPAL.WIDTH" "PETAL.LENGTH" "PETAL.WIDTH" "SPECIES" To retrieve a summary of the data from the database we need to save the results to a local object. The following call saves the results of the query as a local R object, iris.summary. The ROracle function dbGetQuery is used to execute an arbitrary SQL statement against the database. When connected to TimesTen, the SQL statement is processed completely within main memory for the fastest response time. > iris.summary <- dbGetQuery(conn, 'SELECT SPECIES, AVG ("SEPAL.LENGTH") AS AVG_SLENGTH, AVG ("SEPAL.WIDTH") AS AVG_SWIDTH, AVG ("PETAL.LENGTH") AS AVG_PLENGTH, AVG ("PETAL.WIDTH") AS AVG_PWIDTH FROM IRIS GROUP BY ROLLUP (SPECIES)') > iris.summary SPECIES AVG_SLENGTH AVG_SWIDTH AVG_PLENGTH AVG_PWIDTH 1 setosa 5.006000 3.428000 1.462 0.246000 2 versicolor 5.936000 2.770000 4.260 1.326000 3 virginica 6.588000 2.974000 5.552 2.026000 4 <NA> 5.843333 3.057333 3.758 1.199333 Finally, disconnect from the TimesTen Database. > dbCommit (conn) [1] TRUE > dbDisconnect (conn) [1] TRUE We encourage you download Oracle software for evaluation from the Oracle Technology Network. See these links for our software: Times Ten In-Memory Database,  ROracle.  As always, we welcome comments and questions on the TimesTen and  Oracle R technical forums.

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• High Availability for IaaS, PaaS and SaaS in the Cloud

  - by BuckWoody

  Outages, natural disasters and unforeseen events have proved that even in a distributed architecture, you need to plan for High Availability (HA). In this entry I'll explain a few considerations for HA within Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS) and Software-as-a-Service (SaaS). In a separate post I'll talk more about Disaster Recovery (DR), since each paradigm has a different way to handle that. Planning for HA in IaaS IaaS involves Virtual Machines - so in effect, an HA strategy here takes on many of the same characteristics as it would on-premises. The primary difference is that the vendor controls the hardware, so you need to verify what they do for things like local redundancy and so on from the hardware perspective. As far as what you can control and plan for, the primary factors fall into three areas: multiple instances, geographical dispersion and task-switching. In almost every cloud vendor I've studied, to ensure your application will be protected by any level of HA, you need to have at least two of the Instances (VM's) running. This makes sense, but you might assume that the vendor just takes care of that for you - they don't. If a single VM goes down (for whatever reason) then the access to it is lost. Depending on multiple factors, you might be able to recover the data, but you should assume that you can't. You should keep a sync to another location (perhaps the vendor's storage system in another geographic datacenter or to a local location) to ensure you can continue to serve your clients. You'll also need to host the same VM's in another geographical location. Everything from a vendor outage to a network path problem could prevent your users from reaching the system, so you need to have multiple locations to handle this. This means that you'll have to figure out how to manage state between the geo's. If the system goes down in the middle of a transaction, you need to figure out what part of the process the system was in, and then re-create or transfer that state to the second set of systems. If you didn't write the software yourself, this is non-trivial. You'll also need a manual or automatic process to detect the failure and re-route the traffic to your secondary location. You could flip a DNS entry (if your application can tolerate that) or invoke another process to alias the first system to the second, such as load-balancing and so on. There are many options, but all of them involve coding the state into the application layer. If you've simply moved a state-ful application to VM's, you may not be able to easily implement an HA solution. Planning for HA in PaaS Implementing HA in PaaS is a bit simpler, since it's built on the concept of stateless applications deployment. Once again, you need at least two copies of each element in the solution (web roles, worker roles, etc.) to remain available in a single datacenter. Also, you need to deploy the application again in a separate geo, but the advantage here is that you could work out a "shared storage" model such that state is auto-balanced across the world. In fact, you don't have to maintain a "DR" site, the alternate location can be live and serving clients, and only take on extra load if the other site is not available. In Windows Azure, you can use the Traffic Manager service top route the requests as a type of auto balancer. Even with these benefits, I recommend a second backup of storage in another geographic location. Storage is inexpensive; and that second copy can be used for not only HA but DR. Planning for HA in SaaS In Software-as-a-Service (such as Office 365, or Hadoop in Windows Azure) You have far less control over the HA solution, although you still maintain the responsibility to ensure you have it. Since each SaaS is different, check with the vendor on the solution for HA - and make sure you understand what they do and what you are responsible for. They may have no HA for that solution, or pin it to a particular geo, or perhaps they have a massive HA built in with automatic load balancing (which is often the case).   All of these options (with the exception of SaaS) involve higher costs for the design. Do not sacrifice reliability for cost - that will always cost you more in the end. Build in the redundancy and HA at the very outset of the project - if you try to tack it on later in the process the business will push back and potentially not implement HA. References: http://www.bing.com/search?q=windows+azure+High+Availability  (each type of implementation is different, so I'm routing you to a search on the topic - look for the "Patterns and Practices" results for the area in Azure you're interested in)

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• Getting Started with Amazon Web Services in NetBeans IDE

  - by Geertjan

  When you need to connect to Amazon Web Services, NetBeans IDE gives you a nice start. You can drag and drop the "itemSearch" service into a Java source file and then various Amazon files are generated for you. From there, you need to do a little bit of work because the request to Amazon needs to be signed before it can be used. Here are some references and places that got me started: http://associates-amazon.s3.amazonaws.com/signed-requests/helper/index.html http://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSGettingStartedGuide/AWSCredentials.html https://affiliate-program.amazon.com/gp/flex/advertising/api/sign-in.html You definitely need to sign up to the Amazon Associates program and also register/create an Access Key ID, which will also get you a Secret Key, as well. Here's a simple Main class that I created that hooks into the generated RestConnection/RestResponse code created by NetBeans IDE: public static void main(String[] args) {    try {        String searchIndex = "Books";        String keywords = "Romeo and Juliet";        RestResponse result = AmazonAssociatesService.itemSearch(searchIndex, keywords);        String dataAsString = result.getDataAsString();        int start = dataAsString.indexOf("<Author>")+8;        int end = dataAsString.indexOf("</Author>");        System.out.println(dataAsString.substring(start,end));    } catch (Exception ex) {        ex.printStackTrace();    }} Then I deleted the generated properties file and the authenticator and changed the generated AmazonAssociatesService.java file to the following: public class AmazonAssociatesService {    private static void sleep(long millis) {        try {            Thread.sleep(millis);        } catch (Throwable th) {        }    }    public static RestResponse itemSearch(String searchIndex, String keywords) throws IOException {        SignedRequestsHelper helper;        RestConnection conn = null;        Map queryMap = new HashMap();        queryMap.put("Service", "AWSECommerceService");        queryMap.put("AssociateTag", "myAssociateTag");        queryMap.put("AWSAccessKeyId", "myAccessKeyId");        queryMap.put("Operation", "ItemSearch");        queryMap.put("SearchIndex", searchIndex);        queryMap.put("Keywords", keywords);        try {            helper = SignedRequestsHelper.getInstance(                    "ecs.amazonaws.com",                    "myAccessKeyId",                    "mySecretKey");            String sign = helper.sign(queryMap);            conn = new RestConnection(sign);        } catch (IllegalArgumentException | UnsupportedEncodingException | NoSuchAlgorithmException | InvalidKeyException ex) {        }        sleep(1000);        return conn.get(null);    }} Finally, I copied this class into my application, which you can see is referred to above: http://code.google.com/p/amazon-product-advertising-api-sample/source/browse/src/com/amazon/advertising/api/sample/SignedRequestsHelper.java Here's the completed app, mostly generated via the drag/drop shown at the start, but slightly edited as shown above: That's all, now everything works as you'd expect.

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• Application Composer Series: Where and When to use Groovy

  - by Richard Bingham

  This brief post is really intended as more of a reference than an article. The table below highlights two things, firstly where you can add you own custom logic via groovy code (end column), and secondly (middle column) when you might use each particular feature. Obviously this applies only where Application Composer exists, namely Fusion CRM and Oracle Sales Cloud, and is based on current (release 8) functionality. Feature Most Common Use Case Groovy Field Triggers React to run-time data changes. Only fired when the field is changed and upon submit. Y Object Triggers To extend the standard processing logic for an object, based on record creation, updates and deletes. There is a split between these firing events, with some related to UI/ADF actions and others originating in the database. UI Trigger Points: After Create - fires when a new object record is created. Commonly used to set default values for fields. Before Modify - Fires when the end-user tries to modify a field value. Could be used for generic warnings or extra security logic. Before Invalidate - Fires on the parent object when one of its child object records is created, updated, or deleted. For building in relationship logic. Before Remove - Fires when an attempt is made to delete an object record. Can be used to create conditions that prevent deletes. Database Trigger Points: Before Insert in Database - Fires before a new object is inserted into the database. Can be used to ensure a dependent record exists or check for duplicates. After Insert in Database - Fires after a new object is inserted into the database. Could be used to create a complementary record. Before Update in Database -Fires before an existing object is modified in the database. Could be used to check dependent record values. After Update in Database - Fires after an existing object is modified in the database. Could be used to update a complementary record. Before Delete in Database - Fires before an existing object is deleted from the database. Could be used to check dependent record values. After Delete in Database - Fires after an existing object is deleted from the database. Could be used to remove dependent records. After Commit in Database - Fires after the change pending for the current object (insert, update, delete) is made permanent in the current transaction. Could be used when committed data that has passed all validation is required. After Changes Posted to Database - Fires after all changes have been posted to the database, but before they are permanently committed. Could be used to make additional changes that will be saved as part of the current transaction. Y Field Validation Displays a user entered error message based groovy logic validating the field value. The message is shown only when the validation logic returns false, and the logic is triggered only when tabbing out of the field on the user interface. Y Object Validation Commonly used where validation is needed across multiple related fields on the object. Triggered on the submit UI action. Y Object Workflows All Object Workflows are fired upon either record creation or update, along with the option of adding a custom groovy firing condition. Y Field Updates - change another field when a specified one changes. Intended as an easy way to set different run-time values (e.g. pick values for LOV's) plus the value field permits groovy logic entry. Y E-Mail Notification - sends an email notification to specified users/roles. Templates support using run-time value tokens and rich text. N Task Creation - for adding standard tasks for use in the worklist functionality. N Outbound Message - will create and send an XML payload of the related object SDO to a specified endpoint. N Business Process Flow - intended for approval using the seeded process, however can also trigger custom BPMN flows. N Global Functions Utility functions that can be called from any groovy code in Application Composer (across applications). Y Object Functions Utility functions that are local to the parent object. Usually triggered from within 'Buttons and Actions' definitions in Application Composer, although can be called from other code for that object (e.g. from a trigger). Y Add Custom Fields When adding custom fields there are a few places you can include groovy logic. Y Default Value - to add logic within setting the default value when new records are entered. Y Conditionally Updateable - to add logic to set the field to read-only or not. Y Conditionally Required - to add logic to set the field to required or not. Y Formula Field - Used to provide a new aggregate field that is entirely based on groovy logic and other field values. Y Simplified UI Layouts - Advanced Expressions Used for creating dynamic layouts for simplified UI pages where fields and regions show/hide based on run-time context values and logic. Also includes support for the depends-on feature as a trigger. Y Related References This Blog: Application Composer Series Extending Sales Guide: Using Groovy Scripts Groovy Scripting Reference Guide

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• ADF Business Components

  - by Arda Eralp

  ADF Business Components and JDeveloper simplify the development, delivery, and customization of business applications for the Java EE platform. With ADF Business Components, developers aren't required to write the application infrastructure code required by the typical Java EE application to: Connect to the database Retrieve data Lock database records Manage transactions   ADF Business Components addresses these tasks through its library of reusable software components and through the supporting design time facilities in JDeveloper. Most importantly, developers save time using ADF Business Components since the JDeveloper design time makes typical development tasks entirely declarative. In particular, JDeveloper supports declarative development with ADF Business Components to: Author and test business logic in components which automatically integrate with databases Reuse business logic through multiple SQL-based views of data, supporting different application tasks Access and update the views from browser, desktop, mobile, and web service clients Customize application functionality in layers without requiring modification of the delivered application The goal of ADF Business Components is to make the business services developer more productive.   ADF Business Components provides a foundation of Java classes that allow your business-tier application components to leverage the functionality provided in the following areas: Simplifying Data Access Design a data model for client displays, including only necessary data Include master-detail hierarchies of any complexity as part of the data model Implement end-user Query-by-Example data filtering without code Automatically coordinate data model changes with business services layer Automatically validate and save any changes to the database   Enforcing Business Domain Validation and Business Logic Declaratively enforce required fields, primary key uniqueness, data precision-scale, and foreign key references Easily capture and enforce both simple and complex business rules, programmatically or declaratively, with multilevel validation support Navigate relationships between business domain objects and enforce constraints related to compound components   Supporting Sophisticated UIs with Multipage Units of Work Automatically reflect changes made by business service application logic in the user interface Retrieve reference information from related tables, and automatically maintain the information when the user changes foreign-key values Simplify multistep web-based business transactions with automatic web-tier state management Handle images, video, sound, and documents without having to use code Synchronize pending data changes across multiple views of data Consistently apply prompts, tooltips, format masks, and error messages in any application Define custom metadata for any business components to support metadata-driven user interface or application functionality Add dynamic attributes at runtime to simplify per-row state management   Implementing High-Performance Service-Oriented Architecture Support highly functional web service interfaces for business integration without writing code Enforce best-practice interface-based programming style Simplify application security with automatic JAAS integration and audit maintenance "Write once, run anywhere": use the same business service as plain Java class, EJB session bean, or web service   Streamlining Application Customization Extend component functionality after delivery without modifying source code Globally substitute delivered components with extended ones without modifying the application   ADF Business Components implements the business service through the following set of cooperating components: Entity object An entity object represents a row in a database table and simplifies modifying its data by handling all data manipulation language (DML) operations for you. These are basically your 1 to 1 representation of a database table. Each table in the database will have 1 and only 1 EO. The EO contains the mapping between columns and attributes. EO's also contain the business logic and validation. These are you core data services. They are responsible for updating, inserting and deleting records. The Attributes tab displays the actual mapping between attributes and columns, the mapping has following fields: Name : contains the name of the attribute we expose in our data model. Type : defines the data type of the attribute in our application. Column : specifies the column to which we want to map the attribute with Column Type : contains the type of the column in the database   View object A view object represents a SQL query. You use the full power of the familiar SQL language to join, filter, sort, and aggregate data into exactly the shape required by the end-user task. The attributes in the View Objects are actually coming from the Entity Object. In the end the VO will generate a query but you basically build a VO by selecting which EO need to participate in the VO and which attributes of those EO you want to use. That's why you have the Entity Usage column so you can see the relation between VO and EO. In the query tab you can clearly see the query that will be generated for the VO. At this stage we don't need it and just use it for information purpose. In later stages we might use it. Application module An application module is the controller of your data layer. It is responsible for keeping hold of the transaction. It exposes the data model to the view layer. You expose the VO's through the Application Module. This is the abstraction of your data layer which you want to show to the outside word.It defines an updatable data model and top-level procedures and functions (called service methods) related to a logical unit of work related to an end-user task. While the base components handle all the common cases through built-in behavior, customization is always possible and the default behavior provided by the base components can be easily overridden or augmented. When you create EO's, a foreign key will be translated into an association in our model. It defines the type of relation and who is the master and child as well as how the visibility of the association looks like. A similar concept exists to identify relations between view objects. These are called view links. These are almost identical as association except that a view link is based upon attributes defined in the view object. It can also be based upon an association. Here's a short summary: Entity Objects: representations of tables Association: Relations between EO's. Representations of foreign keys View Objects: Logical model View Links: Relationships between view objects Application Model: interface to your application  

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• Processing Text and Binary (Blob, ArrayBuffer, ArrayBufferView) Payload in WebSocket - (TOTD #185)

  - by arungupta

  The WebSocket API defines different send(xxx) methods that can be used to send text and binary data. This Tip Of The Day (TOTD) will show how to send and receive text and binary data using WebSocket. TOTD #183 explains how to get started with a WebSocket endpoint using GlassFish 4. A simple endpoint from that blog looks like: @WebSocketEndpoint("/endpoint") public class MyEndpoint { public void receiveTextMessage(String message) { . . . } } A message with the first parameter of the type String is invoked when a text payload is received. The payload of the incoming WebSocket frame is mapped to this first parameter. An optional second parameter, Session, can be specified to map to the "other end" of this conversation. For example: public void receiveTextMessage(String message, Session session) {     . . . } The return type is void and that means no response is returned to the client that invoked this endpoint. A response may be returned to the client in two different ways. First, set the return type to the expected type, such as: public String receiveTextMessage(String message) { String response = . . . . . . return response; } In this case a text payload is returned back to the invoking endpoint. The second way to send a response back is to use the mapped session to send response using one of the sendXXX methods in Session, when and if needed. public void receiveTextMessage(String message, Session session) {     . . .     RemoteEndpoint remote = session.getRemote();     remote.sendString(...);     . . .     remote.sendString(...);    . . .    remote.sendString(...); } This shows how duplex and asynchronous communication between the two endpoints can be achieved. This can be used to define different message exchange patterns between the client and server. The WebSocket client can send the message as: websocket.send(myTextField.value); where myTextField is a text field in the web page. Binary payload in the incoming WebSocket frame can be received if ByteBuffer is used as the first parameter of the method signature. The endpoint method signature in that case would look like: public void receiveBinaryMessage(ByteBuffer message) {     . . . } From the client side, the binary data can be sent using Blob, ArrayBuffer, and ArrayBufferView. Blob is a just raw data and the actual interpretation is left to the application. ArrayBuffer and ArrayBufferView are defined in the TypedArray specification and are designed to send binary data using WebSocket. In short, ArrayBuffer is a fixed-length binary buffer with no format and no mechanism for accessing its contents. These buffers are manipulated using one of the views defined by one of the subclasses of ArrayBufferView listed below: Int8Array (signed 8-bit integer or char) Uint8Array (unsigned 8-bit integer or unsigned char) Int16Array (signed 16-bit integer or short) Uint16Array (unsigned 16-bit integer or unsigned short) Int32Array (signed 32-bit integer or int) Uint32Array (unsigned 16-bit integer or unsigned int) Float32Array (signed 32-bit float or float) Float64Array (signed 64-bit float or double) WebSocket can send binary data using ArrayBuffer with a view defined by a subclass of ArrayBufferView or a subclass of ArrayBufferView itself. The WebSocket client can send the message using Blob as: blob = new Blob([myField2.value]);websocket.send(blob); where myField2 is a text field in the web page. The WebSocket client can send the message using ArrayBuffer as: var buffer = new ArrayBuffer(10);var bytes = new Uint8Array(buffer);for (var i=0; i<bytes.length; i++) { bytes[i] = i;}websocket.send(buffer); A concrete implementation of receiving the binary message may look like: @WebSocketMessagepublic void echoBinary(ByteBuffer data, Session session) throws IOException {    System.out.println("echoBinary: " + data);    for (byte b : data.array()) {        System.out.print(b);    }    session.getRemote().sendBytes(data);} This method is just printing the binary data for verification but you may actually be storing it in a database or converting to an image or something more meaningful. Be aware of TYRUS-51 if you are trying to send binary data from server to client using method return type. Here are some references for you: JSR 356: Java API for WebSocket - Specification (Early Draft) and Implementation (already integrated in GlassFish 4 promoted builds) TOTD #183 - Getting Started with WebSocket in GlassFish TOTD #184 - Logging WebSocket Frames using Chrome Developer Tools, Net-internals and Wireshark Subsequent blogs will discuss the following topics (not necessary in that order) ... Error handling Custom payloads using encoder/decoder Interface-driven WebSocket endpoint Java client API Client and Server configuration Security Subprotocols Extensions Other topics from the API

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• Collaborative Whiteboard using WebSocket in GlassFish 4 - Text/JSON and Binary/ArrayBuffer Data Transfer (TOTD #189)

  - by arungupta

  This blog has published a few blogs on using JSR 356 Reference Implementation (Tyrus) as its integrated in GlassFish 4 promoted builds. TOTD #183: Getting Started with WebSocket in GlassFish TOTD #184: Logging WebSocket Frames using Chrome Developer Tools, Net-internals and Wireshark TOTD #185: Processing Text and Binary (Blob, ArrayBuffer, ArrayBufferView) Payload in WebSocket TOTD #186: Custom Text and Binary Payloads using WebSocket One of the typical usecase for WebSocket is online collaborative games. This Tip Of The Day (TOTD) explains a sample that can be used to build such games easily. The application is a collaborative whiteboard where different shapes can be drawn in multiple colors. The shapes drawn on one browser are automatically drawn on all other peer browsers that are connected to the same endpoint. The shape, color, and coordinates of the image are transfered using a JSON structure. A browser may opt-out of sharing the figures. Alternatively any browser can send a snapshot of their existing whiteboard to all other browsers. Take a look at this video to understand how the application work and the underlying code. The complete sample code can be downloaded here. The code behind the application is also explained below. The web page (index.jsp) has a HTML5 Canvas as shown: <canvas id="myCanvas" width="150" height="150" style="border:1px solid #000000;"></canvas> And some radio buttons to choose the color and shape. By default, the shape, color, and coordinates of any figure drawn on the canvas are put in a JSON structure and sent as a message to the WebSocket endpoint. The JSON structure looks like: { "shape": "square", "color": "#FF0000", "coords": { "x": 31.59999942779541, "y": 49.91999053955078 }} The endpoint definition looks like: @WebSocketEndpoint(value = "websocket",encoders = {FigureDecoderEncoder.class},decoders = {FigureDecoderEncoder.class})public class Whiteboard { As you can see, the endpoint has decoder and encoder registered that decodes JSON to a Figure (a POJO class) and vice versa respectively. The decode method looks like: public Figure decode(String string) throws DecodeException { try { JSONObject jsonObject = new JSONObject(string); return new Figure(jsonObject); } catch (JSONException ex) { throw new DecodeException("Error parsing JSON", ex.getMessage(), ex.fillInStackTrace()); }} And the encode method looks like: public String encode(Figure figure) throws EncodeException { return figure.getJson().toString();} FigureDecoderEncoder implements both decoder and encoder functionality but thats purely for convenience. But the recommended design pattern is to keep them in separate classes. In certain cases, you may even need only one of them. On the client-side, the Canvas is initialized as: var canvas = document.getElementById("myCanvas");var context = canvas.getContext("2d");canvas.addEventListener("click", defineImage, false); The defineImage method constructs the JSON structure as shown above and sends it to the endpoint using websocket.send(). An instant snapshot of the canvas is sent using binary transfer with WebSocket. The WebSocket is initialized as: var wsUri = "ws://localhost:8080/whiteboard/websocket";var websocket = new WebSocket(wsUri);websocket.binaryType = "arraybuffer"; The important part is to set the binaryType property of WebSocket to arraybuffer. This ensures that any binary transfers using WebSocket are done using ArrayBuffer as the default type seem to be blob. The actual binary data transfer is done using the following: var image = context.getImageData(0, 0, canvas.width, canvas.height);var buffer = new ArrayBuffer(image.data.length);var bytes = new Uint8Array(buffer);for (var i=0; i<bytes.length; i++) { bytes[i] = image.data[i];}websocket.send(bytes); This comprehensive sample shows the following features of JSR 356 API: Annotation-driven endpoints Send/receive text and binary payload in WebSocket Encoders/decoders for custom text payload In addition, it also shows how images can be captured and drawn using HTML5 Canvas in a JSP. How could this be turned in to an online game ? Imagine drawing a Tic-tac-toe board on the canvas with two players playing and others watching. Then you can build access rights and controls within the application itself. Instead of sending a snapshot of the canvas on demand, a new peer joining the game could be automatically transferred the current state as well. Do you want to build this game ? I built a similar game a few years ago. Do somebody want to rewrite the game using WebSocket APIs ? :-) Many thanks to Jitu and Akshay for helping through the WebSocket internals! Here are some references for you: JSR 356: Java API for WebSocket - Specification (Early Draft) and Implementation (already integrated in GlassFish 4 promoted builds) Subsequent blogs will discuss the following topics (not necessary in that order) ... Error handling Interface-driven WebSocket endpoint Java client API Client and Server configuration Security Subprotocols Extensions Other topics from the API

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• Local LINQtoSQL Database For Your Windows Phone 7 Application

  - by Tim Murphy

  There aren’t many applications that are of value without having some for of data store.  In Windows Phone development we have a few options.  You can store text directly to isolated storage.  You can also use a number of third party libraries to create or mimic databases in isolated storage.  With Mango we gained the ability to have a native .NET database approach which uses LINQ to SQL.  In this article I will try to bring together the components needed to implement this last type of data store and fill in some of the blanks that I think other articles have left out. Defining A Database The first things you are going to need to do is define classes that represent your tables and a data context class that is used as the overall database definition.  The table class consists of column definitions as you would expect.  They can have relationships and constraints as with any relational DBMS.  Below is an example of a table definition. First you will need to add some assembly references to the code file. using System.ComponentModel;using System.Data.Linq;using System.Data.Linq.Mapping; You can then add the table class and its associated columns.  It needs to implement INotifyPropertyChanged and INotifyPropertyChanging.  Each level of the class needs to be decorated with the attribute appropriate for that part of the definition.  Where the class represents the table the properties represent the columns.  In this example you will see that the column is marked as a primary key and not nullable with a an auto generated value. You will also notice that the in the column property’s set method It uses the NotifyPropertyChanging and NotifyPropertyChanged methods in order to make sure that the proper events are fired. [Table]public class MyTable: INotifyPropertyChanged, INotifyPropertyChanging{ public event PropertyChangedEventHandler PropertyChanged; private void NotifyPropertyChanged(string propertyName) { if(PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } public event PropertyChangingEventHandler PropertyChanging; private void NotifyPropertyChanging(string propertyName) { if(PropertyChanging != null) { PropertyChanging(this, new PropertyChangingEventArgs(propertyName)); } } private int _TableKey; [Column(IsPrimaryKey = true, IsDbGenerated = true, DbType = "INT NOT NULL Identity", CanBeNull = false, AutoSync = AutoSync.OnInsert)] public int TableKey { get { return _TableKey; } set { NotifyPropertyChanging("TableKey"); _TableKey = value; NotifyPropertyChanged("TableKey"); } } The last part of the database definition that needs to be created is the data context.  This is a simple class that takes an isolated storage location connection string its constructor and then instantiates tables as public properties. public class MyDataContext: DataContext{ public MyDataContext(string connectionString): base(connectionString) { MyRecords = this.GetTable<MyTable>(); } public Table<MyTable> MyRecords;} Creating A New Database Instance Now that we have a database definition it is time to create an instance of the data context within our Windows Phone app.  When your app fires up it should check if the database already exists and create an instance if it does not.  I would suggest that this be part of the constructor of your ViewModel. db = new MyDataContext(connectionString);if(!db.DatabaseExists()){ db.CreateDatabase();} The next thing you have to know is how the connection string for isolated storage should be constructed.  The main sticking point I have found is that the database cannot be created unless the file mode is read/write.  You may have different connection strings but the initial one needs to be similar to the following. string connString = "Data Source = 'isostore:/MyApp.sdf'; File Mode = read write"; Using you database Now that you have done all the up front work it is time to put the database to use.  To make your life a little easier and keep proper separation between your view and your viewmodel you should add a couple of methods to the viewmodel.  These will do the CRUD work of your application.  What you will notice is that the SubmitChanges method is the secret sauce in all of the methods that change data. private myDataContext myDb;private ObservableCollection<MyTable> _viewRecords;public ObservableCollection<MyTable> ViewRecords{ get { return _viewRecords; } set { _viewRecords = value; NotifyPropertyChanged("ViewRecords"); }}public void LoadMedstarDbData(){ var tempItems = from MyTable myRecord in myDb.LocalScans select myRecord; ViewRecords = new ObservableCollection<MyTable>(tempItems);}public void SaveChangesToDb(){ myDb.SubmitChanges();}public void AddMyTableItem(MyTable newScan){ myDb.LocalScans.InsertOnSubmit(newScan); myDb.SubmitChanges();}public void DeleteMyTableItem(MyTable newScan){ myDb.LocalScans.DeleteOnSubmit(newScan); myDb.SubmitChanges();} Updating existing database What happens when you need to change the structure of your database?  Unfortunately you have to add code to your application that checks the version of the database which over time will create some pollution in your codes base.  On the other hand it does give you control of the update.  In this example you will see the DatabaseSchemaUpdater in action.  Assuming we added a “Notes” field to the MyTable structure, the following code will check if the database is the latest version and add the field if it isn’t. if(!myDb.DatabaseExists()){ myDb.CreateDatabase();}else{ DatabaseSchemaUpdater dbUdater = myDb.CreateDatabaseSchemaUpdater(); if(dbUdater.DatabaseSchemaVersion < 2) { dbUdater.AddColumn<MyTable>("Notes"); dbUdater.DatabaseSchemaVersion = 2; dbUdater.Execute(); }} Summary This approach does take a fairly large amount of work, but I think the end product is robust and very native for .NET developers.  It turns out to be worth the investment. del.icio.us Tags: Windows Phone,Windows Phone 7,LINQ to SQL,LINQ,Database,Isolated Storage

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• If I were in a Silverlight focus group, here is ten things I would say.

  - by mbcrump

  Silverlight is a great product right off the shelf. I use it, love it and spend a lot of time helping the community understand it. This however, doesn’t mean that I don’t think that it can get better. If I were invited to a Microsoft Focus Group about Silverlight here is 10 things I would say:  We need more navigation templates. I’ve found (4) templates that Microsoft has released (Cosmo, Windows 7, Accent and JetPack). This number needs to be around 16. In order to get more people developing for Silverlight, we need to give them a variety of templates to get them off the ground quickly. Silverlight needs to ship with the next version of Windows. At least version 4 needs to be pre-installed on Windows going forward. It’s small, in its own sandbox and I cannot find a reason for it not to be included. Silverlight needs to run on more platforms.  iOS and Android are the key here. I think Microsoft should shoot for Android first since I believe Android will take the lead in the mobile market (at least for the short-term). It would also be great to see Microsoft use Silverlight as the focus on their new tablets / “AppleTV”. I would even invest in getting it working with Kinect. When creating a new project in Silverlight, we should have the option to create a Unit Test. Most Silverlight developers are not unit testing. If this is surprising to you then you need to get out and talk to more developers. I partially blame this on Microsoft. When you create a new ASP.NET MVC application, you simply put a check to create a Unit Test project. We need the same thing for Silverlight. We should steer the developer into the right direction. Design patterns such as MVVM need to be easier to implement in Silverlight solutions.  I’d go so far as to say that MVVM Light should ship with Visual Studio. With the project / item templates and code snippets, Laurent puts you into the right direction. This is the way that it should have been. Easy for the 9-5 developer to grasp. I believe the majority of developers use code behind because that’s what is in all the demos provided by Microsoft. They are not trying to write sucky code it is that they simply don’t know a better way.  The XAP Files should be obfuscated/unused references deleted by default when in “Release” mode. A better Silverlight experience starts with a smaller XAP file. The less that a user has to download is the better, even with the majority of people on broadband. I would also recommend built-in obfuscation by Microsoft. People are paranoid that they can rename the .zip and run it through reflector. Get rid of the boring install experiences. Here is a great write up on what I’m talking about. The default “Install Silverlight” and “Loading screens” suck. They suck bad. We need a choice of templates that a professional designer has created.  Silverlight needs to supports more image formats. For example: it would be great to use .gif’s without converting them to .png.    Switching between Blend 4 and VS2010 to develop a Silverlight application is a pain. Probably one of the biggest issues that I can’t think of a good solution for. It would be nice if VS2012 had the best of both worlds and you never have to leave VS. We need reporting controls with SSRS included with the Silverlight Toolkit. I can’t think of another control that we need built into the toolkit. It would also be helpful to have export to .xls, .pdf and .doc included with the control. I hope that this post will at least get a few people talking. Who knows, Microsoft could be working on these things right now. Thanks for reading!  Subscribe to my feed CodeProject

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• What free space thresholds/limits are advisable for 640 GB and 2 TB hard disk drives with ZEVO ZFS on OS X?

  - by Graham Perrin

  Assuming that free space advice for ZEVO will not differ from advice for other modern implementations of ZFS … Question Please, what percentages or amounts of free space are advisable for hard disk drives of the following sizes? 640 GB 2 TB Thoughts A standard answer for modern implementations of ZFS might be "no more than 96 percent full". However if apply that to (say) a single-disk 640 GB dataset where some of the files most commonly used (by VirtualBox) are larger than 15 GB each, then I guess that blocks for those files will become sub optimally spread across the platters with around 26 GB free. I read that in most cases, fragmentation and defragmentation should not be a concern with ZFS. Sill, I like the mental picture of most fragments of a large .vdi in reasonably close proximity to each other. (Do features of ZFS make that wish for proximity too old-fashioned?) Side note: there might arise the question of how to optimise performance after a threshold is 'broken'. If it arises, I'll keep it separate. Background On a 640 GB StoreJet Transcend (product ID 0x2329) in the past I probably went beyond an advisable threshold. Currently the largest file is around 17 GB –  – and I doubt that any .vdi or other file on this disk will grow beyond 40 GB. (Ignore the purple masses, those are bundles of 8 MB band files.) Without HFS Plus: the thresholds of twenty, ten and five percent that I associate with Mobile Time Machine file system need not apply. I currently use ZEVO Community Edition 1.1.1 with Mountain Lion, OS X 10.8.2, but I'd like answers to be not too version-specific. References, chronological order ZFS Block Allocation (Jeff Bonwick's Blog) (2006-11-04) Space Maps (Jeff Bonwick's Blog) (2007-09-13) Doubling Exchange Performance (Bizarre ! Vous avez dit Bizarre ?) (2010-03-11) … So to solve this problem, what went in 2010/Q1 software release is multifold. The most important thing is: we increased the threshold at which we switched from 'first fit' (go fast) to 'best fit' (pack tight) from 70% full to 96% full. With TB drives, each slab is at least 5GB and 4% is still 200MB plenty of space and no need to do anything radical before that. This gave us the biggest bang. Second, instead of trying to reuse the same primary slabs until it failed an allocation we decided to stop giving the primary slab this preferential threatment as soon as the biggest allocation that could be satisfied by a slab was down to 128K (metaslab_df_alloc_threshold). At that point we were ready to switch to another slab that had more free space. We also decided to reduce the SMO bonus. Before, a slab that was 50% empty was preferred over slabs that had never been used. In order to foster more write aggregation, we reduced the threshold to 33% empty. This means that a random write workload now spread to more slabs where each one will have larger amount of free space leading to more write aggregation. Finally we also saw that slab loading was contributing to lower performance and implemented a slab prefetch mechanism to reduce down time associated with that operation. The conjunction of all these changes lead to 50% improved OLTP and 70% reduced variability from run to run … OLTP Improvements in Sun Storage 7000 2010.Q1 (Performance Profiles) (2010-03-11) Alasdair on Everything » ZFS runs really slowly when free disk usage goes above 80% (2010-07-18) where commentary includes: … OpenSolaris has changed this in onnv revision 11146 … [CFT] Improved ZFS metaslab code (faster write speed) (2010-08-22)

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• Windows 7 Boot to VHD using a VHD clone of the system drive

  - by daveh551

  This seems like a not too difficult problem, and, after several hurdles, I'm maddeningly close. But I can't quite get there. I'm running Windows 7 in development shop. I want to start using VS2010 to work on some stuff that won't be released for awhile. My boss said no beta code on the production machine, but I could run VS2010 for this project IF I could do it in an isolated environment, like a virtual PC. Well, I've used the beta and RC of Win7 on VPC's before, and it was painfully slow because of the VPC environment. But everyone has been singing the praises of Windows 7's boot-to-VHD capability, where only the disk is virtualized, and you're actually running on the hardware. Supposed to be little slower, but nowhere near the speed penalty of VPC. I've spent a fair amount of time getting everything installed the way I want it. So I figured, I'll just clone my system drive using Disk2VHD, and boot off of that, and then install VS2010 onto that. (I keep most of my user data, including all my projects, in a separate partition, so that wouldn't have to be duplicated and would still be available.) Well, I had some difficulties with that, owing mainly to the fact that I was using an old version of Disk2VHD - (get the latest if you're going to try it.) But I did finally get it to boot. (Scott Hanselman has a good blog post on boot to VHD). But it wasn't exactly what I was expecting or hoping for. What I expected was that the VHD would become the C: drive, and the original (physical) C: drive would be either hidden or mounted under a different letter, and thus isolated and protected from any changes. What you actually get is that the VHD becomes the D: drive AND you boot from the D: drive, BUT your original C: drive is still there. Which is sort of okay EXCEPT that the Registry on the VHD is a clone of the Registry on C: drive, and includes many hard-coded references to C:. So the result is that some things come from (and modify) D: (the VHD), but some things come from (and modify) C:. (If you open a cmd prompt and do a SET to look at your environment variables, you will see a mixture of D:\ and C:\ paths.) So I don't really have an isolated environment. Most importantly, %ProgramFiles% is still set to C:\Program Files. What I really need is a tool that can access the registry files on the mounted VHD AS FILES, not as registry entries, and do a global search and replace on all the C:\ in strings to D:. I haven't found such a program. (I've tried to do it with a program called Registry Replace, but, even when running as Administrator, there are certain entries that the Registry won't let you change.) Does anyone know of one? Or any other solution to my problem (other than starting from scratch with a clean VHD and installing Win7 and all my programs on it.)?

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