Search Results

Search found 16838 results on 674 pages for 'writing patterns dita cms'.

Page 631/674 | < Previous Page | 627 628 629 630 631 632 633 634 635 636 637 638  | Next Page >

• Ajax problem not displaying data using multiple javascript calls...

  - by Ronedog

  I'm writing an app that uses ajax to retrieve data from a mysql db using php. Because of the nature of the app, the user clicks an href link that has an "onclick" event used to call the javascript/ajax. I'm retrieving the data from mysql, then calling a separate php function which creates a small html table with the necessary data in it. The new table gets passed back to the responseText and is displayed inside a div tag. The tables only have around 10-20 rows of data in them. This functionality is working fine and displays the data in html form exactly as it needs to be on the page. The problem is this. the HREF "onclick" event needs to run multiple scripts one right after the other. The first script updates the "existing" data and inside the "update_existing" function is a call to refresh a section of the page with the updated HTML from the responseText. Then when that is done a "display_html" function is called which also updates a different section of the page with it's newly created HTML table. The event looks like this: Update This string gets built dynamically using php with parameters supplied, but for this example I simply took the parameters out so it didn't get confusing. The "update_existion() function actually calls the display_html() function which updates a section of the page as needed. I need to update a different section of the page on the same click of the mouse right after the update, which is why I'm calling the display_html() again, right after it. The problem is only the last call is being updated on my screen. In other words, the 2nd function call "display_html()" executes and displays the refreshed data just fine, but the previous call to update_existing() runs and updates the database properly, but doesn't display on the screen unless I press the browsers "refresh" button, which of course displays the new data exactly how I want it to, but I don't want the users to have to press the "refresh" button. I tried adding multiple "display_html() calls one right after the other, separating all of them with the semicolon and learned that only the very last function call actually refreshed the div element on the html page with the table information, although all the previous display_html() calls worked, they couldn't be seen on the page without a refresh of the browser. Is this a problem with javascript, or the ajax call, or is this a limitation in the DOM that only allows one element to be updated at a time. The ajax call is asynchroneous, but I've tried both, only async works period. This is the same in both Firefox and Internet Explorer Any ideas what's going on and how to get around it so I can run these multiple scripts?

  Read the article

• Stack and queue operations on the same array.

  - by Passonate Learner

  Hi. I've been thinking about a program logic, but I cannot draw a conclusion to my problem. Here, I've implemented stack and queue operations to a fixed array. int A[1000]; int size=1000; int top; int front; int rear; bool StackIsEmpty() { return (top==0); } bool StackPush( int x ) { if ( top >= size ) return false; A[top++] = x; return true; } int StackTop( ) { return A[top-1]; } bool StackPop() { if ( top <= 0 ) return false; A[--top] = 0; return true; } bool QueueIsEmpty() { return (front==rear); } bool QueuePush( int x ) { if ( rear >= size ) return false; A[rear++] = x; return true; } int QueueFront( ) { return A[front]; } bool QueuePop() { if ( front >= rear ) return false; A[front++] = 0; return true; } It is presumed(or obvious) that the bottom of the stack and the front of the queue is pointing at the same location, and vice versa(top of the stack points the same location as rear of the queue). For example, integer 1 and 2 is inside an array in order of writing. And if I call StackPop(), the integer 2 will be popped out, and if I call QueuePop(), the integer 1 will be popped out. My problem is that I don't know what happens if I do both stack and queue operations on the same array. The example above is easy to work out, because there are only two values involved. But what if there are more than 2 values involved? For example, if I call StackPush(1); QueuePush(2); QueuePush(4); StackPop(); StackPush(5); QueuePop(); what values will be returned in the order of bottom(front) from the final array? I know that if I code a program, I would receive a quick answer. But the reason I'm asking this is because I want to hear a logical explanations from a human being, not a computer.

  Read the article

• Storing simulation results in a persistent manner for Python?

  - by Az

  Background: I'm running multiple simuations on a set of data. For each session, I'm allocating projects to students. The difference between each session is that I'm randomising the order of the students such that all the students get a shot at being assigned a project they want. I was writing out some of the allocations in a spreadsheet (i.e. Excel) and it basically looked like this (tiny snapshot, actual table extends to a few thousand sessions, roughly 100 students). | | Session 1 | Session 2 | Session 3 | |----------|-----------|-----------|-----------| |Stu1 |Proj_AA |Proj_AB |Proj_AB | |----------|-----------|-----------|-----------| |Stu2 |Proj_AB |Proj_AA |Proj_AC | |----------|-----------|-----------|-----------| |Stu3 |Proj_AC |Proj_AC |Proj_AA | |----------|-----------|-----------|-----------| Now, the code that deals with the allocation currently stores a session in an object. The next time the allocation is run, the object is over-written. Thus what I'd really like to do is to store all the allocation results. This is important since I later need to derive from the data, information such as: which project Stu1 got assigned to the most or perhaps how popular Proj_AC was (how many times it was assigned / number of sessions). Question(s): What methods can I possibly use to basically store such session information persistently? Basically, each session output needs to add itself to the repository after ending and before beginning the next allocation cycle. One solution that was suggested by a friend was mapping these results to a relational database using SQLAlchemy. I kind of like the idea since this does give me an opportunity to delve into databases. Now the database structure I was recommended was: |----------|-----------|-----------| |Session |Student |Project | |----------|-----------|-----------| |1 |Stu1 |Proj_AA | |----------|-----------|-----------| |1 |Stu2 |Proj_AB | |----------|-----------|-----------| |1 |Stu3 |Proj_AC | |----------|-----------|-----------| |2 |Stu1 |Proj_AB | |----------|-----------|-----------| |2 |Stu2 |Proj_AA | |----------|-----------|-----------| |2 |Stu3 |Proj_AC | |----------|-----------|-----------| |3 |Stu1 |Proj_AB | |----------|-----------|-----------| |3 |Stu2 |Proj_AC | |----------|-----------|-----------| |3 |Stu3 |Proj_AA | |----------|-----------|-----------| Here, it was suggested that I make the Session and Student columns a composite key. That way I can access a specific record for a particular student for a particular session. Or I can merely get the entire allocation run for a particular session. Questions: Is the idea a good one? How does one implement and query a composite key using SQLAlchemy? What happens to the database if a particular student is not assigned a project (happens if all projects that he wants are taken)? In the code, if a student is not assigned a project, instead of a proj_id he simply gets None for that field/object. I apologise for asking multiple questions but since these are closely-related, I thought I'd ask them in the same space.

  Read the article

• Undefined Behavior and Sequence Points Reloaded

  - by Nawaz

  Consider this topic a sequel of the following topic: Previous Installment Undefined Behavior and Sequence Points Let's revisit this funny and convoluted expression (the italicized phrases are taken from the above topic *smile* ): i += ++i; We say this invokes undefined-behavior. I presume that when say this, we implicitly assume that type of i is one of built-in types. So my question is: what if the type of i is a user-defined type? Say it's type is Index which is defined later in this post (see below). Would it still invoke undefined-behavior? If yes, why? Is it not equivalent to writing i.operator+=(i.operator ++()); or even syntactically simpler i.add(i.inc());? Or, do they too invoke undefined-behavior? If no, why not? After all, the object i gets modified twice between consecutive sequence points. Please recall the rule of thumb : an expression can modify an object's value only once between consecutive "sequence points. And if i += ++i is an expression, then it must invoke undefined-behavior. If so, then it's equivalents i.operator+=(i.operator ++()); and i.add(i.inc()); must also invoke undefined-behavior which seems to be untrue! (as far as I understand) Or, i += ++i is not an expression to begin with? If so, then what is it and what is the definition of expression? If it's an expression, and at the same time, it's behavior is also well-defined, then it implies that number of sequence points associated with an expression somehow depends on the type of operands involved in the expression. Am I correct (even partly)? By the way, how about this expression? a[++i] = i; //taken from the previous topic. but here type of `i` is Index. class Index { int state; public: Index(int s) : state(s) {} Index& operator++() { state++; return *this; } Index& operator+=(const Index & index) { state+= index.state; return *this; } operator int() { return state; } Index & add(const Index & index) { state += index.state; return *this; } Index & inc() { state++; return *this; } };

  Read the article

• Printf in assembler doesn't print

  - by Gaim

  Hi there, I have got a homework to hack program using buffer overflow ( with disassambling, program was written in C++, I haven't got the source code ). I have already managed it but I have a problem. I have to print some message on the screen, so I found out address of printf function, pushed address of "HACKED" and address of "%s" on the stack ( in this order ) and called that function. Called code passed well but nothing had been printed. I have tried to simulate the environment like in other place in the program but there has to be something wrong. Do you have any idea what I am doing wrong that I have no output, please? Thanks a lot EDIT: This program is running on Windows XP SP3 32b, written in C++, Intel asm there is the "hack" code CPU Disasm Address Hex dump Command Comments 0012F9A3 90 NOP ;hack begins 0012F9A4 90 NOP 0012F9A5 90 NOP 0012F9A6 89E5 MOV EBP,ESP 0012F9A8 83EC 7F SUB ESP,7F ;creating a place for working data 0012F9AB 83EC 7F SUB ESP,7F 0012F9AE 31C0 XOR EAX,EAX 0012F9B0 50 PUSH EAX 0012F9B1 50 PUSH EAX 0012F9B2 50 PUSH EAX 0012F9B3 89E8 MOV EAX,EBP 0012F9B5 83E8 09 SUB EAX,9 0012F9B8 BA 1406EDFF MOV EDX,FFED0614 ;address to jump, it is negative because there mustn't be 00 bytes 0012F9BD F7DA NOT EDX 0012F9BF FFE2 JMP EDX ;I have to jump because there are some values overwritten by the program 0012F9C1 90 NOP 0012F9C2 0090 00000000 ADD BYTE PTR DS:[EAX],DL 0012F9C8 90 NOP 0012F9C9 90 NOP 0012F9CA 90 NOP 0012F9CB 90 NOP 0012F9CC 6C INS BYTE PTR ES:[EDI],DX ; I/O command 0012F9CD 65:6E OUTS DX,BYTE PTR GS:[ESI] ; I/O command 0012F9CF 67:74 68 JE SHORT 0012FA3A ; Superfluous address size prefix 0012F9D2 2069 73 AND BYTE PTR DS:[ECX+73],CH 0012F9D5 203439 AND BYTE PTR DS:[EDI+ECX],DH 0012F9D8 34 2C XOR AL,2C 0012F9DA 2066 69 AND BYTE PTR DS:[ESI+69],AH 0012F9DD 72 73 JB SHORT 0012FA52 0012F9DF 74 20 JE SHORT 0012FA01 0012F9E1 3120 XOR DWORD PTR DS:[EAX],ESP 0012F9E3 6C INS BYTE PTR ES:[EDI],DX ; I/O command 0012F9E4 696E 65 7300909 IMUL EBP,DWORD PTR DS:[ESI+65],-6F6FFF8D 0012F9EB 90 NOP 0012F9EC 90 NOP 0012F9ED 90 NOP 0012F9EE 31DB XOR EBX,EBX ; hack continues 0012F9F0 8818 MOV BYTE PTR DS:[EAX],BL ; writing 00 behind word "HACKED" 0012F9F2 83E8 06 SUB EAX,6 0012F9F5 50 PUSH EAX ; address of "HACKED" 0012F9F6 B8 3B8CBEFF MOV EAX,FFBE8C3B 0012F9FB F7D0 NOT EAX 0012F9FD 50 PUSH EAX ; address of "%s" 0012F9FE B8 FFE4BFFF MOV EAX,FFBFE4FF 0012FA03 F7D0 NOT EAX 0012FA05 FFD0 CALL EAX ;address of printf This code is really ugly because I am new in assembler and there mustn't be null bytes because of buffer-overflow bug

  Read the article

• jQuery: .toggle() doesnt work properly on two different elements.

  - by Marius

  Hello there, This is my markup: <table class="col1table" cellspacing="0" cellpadding="0"> <tr> <td><a class="tips_trigger" href="#"><img src="/img/design/icon_tips_venn.png" /></a></td> <td><a class="facebook_trigger" href="#"><img src="/img/design/icon_facebook.png" /></a></td> <td><a class="twitter_trigger" href="#"><img src="/img/design/icon_twitter.png" /></a></td> <td><a class="myspace_trigger" href="#"><img src="/img/design/icon_myspace.png" /></a></td> </tr> <tr> <td><a class="tips_trigger" href="#">TIPS EN VENN</a></td> <td><a class="facebook_trigger" href="#">FACEBOOK</a></td> <td><a class="twitter_trigger" href="#">TWITTER</a></td> <td><a class="myspace_trigger" href="#">MYSPACE</a></td> </tr> </table> This is the mark-up for a tool-tip: <div id="message_tips" class="toolTip">Lorem ipsum dolor sit amet.<br /><br /><br /><br /><br /><br />Lorem ipsum dolor sit amet.</div> This is my code to hide/unhide tooltip for .tips_trigger (the tooltip has id: "#message_tips"). Notice that there is one .tips_trigger on each row in the table. And there will be one tooltip per "..._trigger-class". $('.tips_trigger').toggle(function(event){ event.preventDefault(); $('#message_tips').css('display', 'block'); }, function(event){ $('#message_tips').css('display', 'none'); }); I have two problems: 1. Each of the tips_trigger-classes seems to work the script independatly. What I mean by that is if I click tips_trigger in the first row, it displays the tool-tip. If i click tips_trigger in the second row straight after, it displays the tool-tip again. I have to click the exact same tips_trigger-class istance twice for it to hide it. How can I overcome this problem? 2. Each of the "..._trigger"-classes will have a tool-tip, not just ".tips_trigger". Is there a way to alter my current script so that it works for multiple unhides/hides instead of writing one script per class? Kind regards, Marius

  Read the article

• Written a resharper plugin that modifies the TextControl?

  - by Ajaxx

  Resharper claims to eat it's own dogfood, specifically, they claim that many of the features of Resharper are written ontop of R# (OpenAPI). I'm writing a simple plugin to fix up comments of the current document of a selection. When this plugin is run, it throws an exception as follows: Document can be modified inside a command scope only I've researched the error and can't find anything to help with this, so I'm hoping that possibly, you've written a plugin to accomplish this. If not, I hope the snippet is enough to help others get their own plugins underway. using System; using System.IO; using System.Windows.Forms; using JetBrains.ActionManagement; using JetBrains.DocumentModel; using JetBrains.IDE; using JetBrains.TextControl; using JetBrains.Util; namespace TinkerToys.Actions { [ActionHandler("TinkerToys.RewriteComment")] public class RewriteCommentAction : IActionHandler { #region Implementation of IActionHandler /// <summary> /// Updates action visual presentation. If presentation.Enabled is set to false, Execute /// will not be called. /// </summary> /// <param name="context">DataContext</param> /// <param name="presentation">presentation to update</param> /// <param name="nextUpdate">delegate to call</param> public bool Update(IDataContext context, ActionPresentation presentation, DelegateUpdate nextUpdate) { ITextControl textControl = context.GetData(DataConstants.TEXT_CONTROL); return textControl != null; } /// <summary> /// Executes action. Called after Update, that set ActionPresentation.Enabled to true. /// </summary> /// <param name="context">DataContext</param> /// <param name="nextExecute">delegate to call</param> public void Execute(IDataContext context, DelegateExecute nextExecute) { ITextControl textControl = context.GetData(DataConstants.TEXT_CONTROL); if (textControl != null) { TextRange textSelectRange; ISelectionModel textSelectionModel = textControl.SelectionModel; if ((textSelectionModel != null) && textSelectionModel.HasSelection()) { textSelectRange = textSelectionModel.Range; } else { textSelectRange = new TextRange(0, textControl.Document.GetTextLength()); } IDocument textDocument = textControl.Document; String textSelection = textDocument.GetText(textSelectRange); if (textSelection != null) { StringReader sReader = new StringReader(textSelection); StringWriter sWriter = new StringWriter(); Converter.Convert(sReader, sWriter); textSelection = sWriter.ToString(); textDocument.ReplaceText(textSelectRange, textSelection); } } } #endregion } } So what is this command scope it wants so badly? I had some additional logging in this prior to posting it so I'm absolutely certain that both the range and text are valid. In addition, the error seems to indicate that I'm missing some scope that I've been, as yet, unable to find.

  Read the article

• architecture python question

  - by tom smith

  hi. creating a distributed crawling python app. it consists of a master server, and associated client apps that will run on client servers. the purpose of the client app is to run across a targeted site, to extract specific data. the clients need to go "deep" within the site, behind multiple levels of forms, so each client is specifically geared towards a given site. each client app looks something like main: parse initial url call function level1 (data1) function level1 (data) parse the url, for data1 use the required xpath to get the dom elements call the next function call level2 (data) function level2 (data2) parse the url, for data2 use the required xpath to get the dom elements call the next function call level3 function level3 (dat3) parse the url, for data3 use the required xpath to get the dom elements call the next function call level4 function level4 (data) parse the url, for data4 use the required xpath to get the dom elements at the final function.. --all the data output, and eventually returned to the server --at this point the data has elements from each function... my question: given that the number of calls that is made to the child function by the current function varies, i'm trying to figure out the best approach. each function essentialy fetches a page of content, and then parses the page using a number of different XPath expressions, combined with different regex expressions depending on the site/page. if i run a client on a single box, as a sequential process, it'll take awhile, but the load on the box is rather small. i've thought of attempting to implement the child functions as threads from the current function, but that could be a nightmare, as well as quickly bring the "box" to its knees! i've thought of breaking the app up in a manner that would allow the master to essentially pass packets to the client boxes, in a way to allow each client/function to be run directly from the master. this process requires a bit of rewrite, but it has a number of advantages. a bunch of redundancy, and speed. it would detect if a section of the process was crashing and restart from that point. but not sure if it would be any faster... i'm writing the parsing scripts in python.. so... any thoughts/comments would be appreciated... i can get into a great deal more detail, but didn't want to bore anyone!! thanks! tom

  Read the article

• Adding a generic image field onto a ModelForm in django

  - by Prairiedogg

  I have two models, Room and Image. Image is a generic model that can tack onto any other model. I want to give users a form to upload an image when they post information about a room. I've written code that works, but I'm afraid I've done it the hard way, and specifically in a way that violates DRY. Was hoping someone who's a little more familiar with django forms could point out where I've gone wrong. Update: I've tried to clarify why I chose this design in comments to the current answers. To summarize: I didn't simply put an ImageField on the Room model because I wanted more than one image associated with the Room model. I chose a generic Image model because I wanted to add images to several different models. The alternatives I considered were were multiple foreign keys on a single Image class, which seemed messy, or multiple Image classes, which I thought would clutter my schema. I didn't make this clear in my first post, so sorry about that. Seeing as none of the answers so far has addressed how to make this a little more DRY I did come up with my own solution which was to add the upload path as a class attribute on the image model and reference that every time it's needed. # Models class Image(models.Model): content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField() content_object = generic.GenericForeignKey('content_type', 'object_id') image = models.ImageField(_('Image'), height_field='', width_field='', upload_to='uploads/images', max_length=200) class Room(models.Model): name = models.CharField(max_length=50) image_set = generic.GenericRelation('Image') # The form class AddRoomForm(forms.ModelForm): image_1 = forms.ImageField() class Meta: model = Room # The view def handle_uploaded_file(f): # DRY violation, I've already specified the upload path in the image model upload_suffix = join('uploads/images', f.name) upload_path = join(settings.MEDIA_ROOT, upload_suffix) destination = open(upload_path, 'wb+') for chunk in f.chunks(): destination.write(chunk) destination.close() return upload_suffix def add_room(request, apartment_id, form_class=AddRoomForm, template='apartments/add_room.html'): apartment = Apartment.objects.get(id=apartment_id) if request.method == 'POST': form = form_class(request.POST, request.FILES) if form.is_valid(): room = form.save() image_1 = form.cleaned_data['image_1'] # Instead of writing a special function to handle the image, # shouldn't I just be able to pass it straight into Image.objects.create # ...but it doesn't seem to work for some reason, wrong syntax perhaps? upload_path = handle_uploaded_file(image_1) image = Image.objects.create(content_object=room, image=upload_path) return HttpResponseRedirect(room.get_absolute_url()) else: form = form_class() context = {'form': form, } return direct_to_template(request, template, extra_context=context)

  Read the article

• What was "The Next Big Thing" when you were just starting out in programming?

  - by Andrew

  I'm at the beginning of my career and there are lots of things which are being touted as "The Next Big Thing". For example: Dependency Injection (Spring, etc) MVC (Struts, ASP.NET MVC) ORMs (Linq To SQL, Hibernate) Agile Software Development These things have probably been around for some time, but I've only just started out. And don't get me wrong, I think these things are great! So, what was "The Next Big Thing" when you were starting out? When was it? Were people sceptical of it at first? Why? Did you think it would catch on? Did it pan out and become widely accepted/used? If not, why not? EDIT It's been nearly a week since I first posted this question and I can safely say that I did not expect such explosive interest. I asked the question so that I could gain a perspective of what kinds of innovations in programming people thought were most important when they were starting out. At the time of writing this I have read ~95% of all answers. To answer a few questions, the "Next Big Things" I listed are ones that I am currently really excited about and that I had not really been exposed to until I started working. I'm hoping to implement some or all of these in the near future at my current workplace. To many people they are probably old news. In regards to the "is this a real question" debate, I can see that obviously hasn't been settled yet. I feel bad whenever I read a comment saying that these kinds of questions take away from the real meaning of SO. I'm not wholly convinced that it doesn't. On the other hand, I have seen a lot of comments saying what a great question it is. Anyway, I have chosen "The Internet!" as my answer to this question. I don't think (in my very humble opinion, and, it seems many SOers opinions) that many things related to programming can compare. Nowadays every business and their dog has a website which can do anything from simply supplying information to purchasing goods halfway around the world to updating your blog. And of course, all these businesses need people like us. Thanks to everyone for all the great answers!

  Read the article

• Recursive XSLT, part 2

  - by Eric

  Ok, following on from my question here. Lets say my pages are now like this: A.xml: <page> <header>Page A</header> <content-a>Random content for page A</content-a> <content-b>More of page A's content</content-b> <content-c>More of page A's content</content-c> <!-- This doesn't keep going: there are a predefined number of sections --> </page> B.xml: <page include="A.xml"> <header>Page B</header> <content-a>Random content for page B</content-a> <content-b>More of page B's content</content-b> <content-c>More of page B's content</content-c> </page> C.xml: <page include="B.xml"> <header>Page C</header> <content-a>Random content for page C</content-a> <content-b>More of page C's content</content-b> <content-c>More of page C's content</content-c> </page> After the transform (on C.xml), I'd like to end up with this: <h1>Page C</h1> <div> <p>Random content for page C</p> <p>Random content for page B</p> <p>Random content for page A</p> </div> <div> <p>More of page C's content</p> <p>More of page B's content</p> <p>More of page A's content</p> </div> <div> <p>Yet more of page C's content</p> <p>Yet more of page B's content</p> <p>Yet more of page A's content</p> </div> I know that I can use document(@include) to include another document. However, the recursion is a bit beyond me. How would I go about writing such a transform?

  Read the article

• Advice for Architecture Design Logic for software application

  - by Prasad

  Hi, I have a framework of basic to complex set of objects/classes (C++) running into around 500. With some rules and regulations - all these objects can communicate with each other and hence can cover most of the common queries in the domain. My Dream: I want to provide these objects as icons/glyphs (as I learnt recently) on a workspace. All these objects can be dragged/dropped into the workspace. They have to communicate only through their methods(interface) and in addition to few iterative and conditional statements. All these objects are arranged finally to execute a protocol/workflow/dataflow/process. After drawing the flow, the user clicks the Execute/run button. All the user interaction should be multi-touch enabled. The best way to show my dream is : Jeff Han's Multitouch Video. consider Jeff is playing with my objects instead of the google maps. :-) it should be like playing a jigsaw puzzle. Objective: how can I achieve the following while working on this final product: a) the development should be flexible to enable provision for web services b) the development should enable easy web application development c) The development should enable client-server architecture - d) further it should also enable mouse based drag/drop desktop application like Adobe programs etc. I mean to say: I want to economize on investments. Now I list my efforts till now in design : a) Created an Editor (VB) where the user writes (manually) the object / class code b) On Run/Execute, the code is copied into a main() function and passed to interpreter. c) Catch the output and show it in the console. The interpreter can be separated to become a server and the Editor can become the client. This needs lot of standard client-server architecture work. But some how I am not comfortable in the tightness of this system. Without interpreter is there much faster and better embeddable solution to this? - other than writing a special compiler for these objects. Recently learned about AXIS-C++ can help me - looks like - a friend suggested. Is that the way to go ? Here are my questions: (pl. consider me a self taught programmer and NOT my domain) a) From the stage of C++ objects to multi-touch product, how can I make sure I will develop the parallel product/service models as well.? What should be architecture aspects I should consider ? b) What technologies are best suited for this? c) If I am thinking of moving to Cloud Computing, how difficult/ how redundant / how unnecessary my efforts will be ? d) How much time in months would it take to get the first beta ? I take the liberty to ask if any of the experts here are interested in this project, please email me: [email protected] Thank you for any help. Looking forward.

  Read the article

• Java: Reading a pdf file from URL into Byte array/ByteBuffer in an applet.

  - by Pol

  I'm trying to figure out why this particular snippet of code isn't working for me. I've got an applet which is supposed to read a .pdf and display it with a pdf-renderer library, but for some reason when I read in the .pdf files which sit on my server, they end up as being corrupt. I've tested it by writing the files back out again. I've tried viewing the applet in both IE and Firefox and the corrupt files occur. Funny thing is, when I trying viewing the applet in Safari (for Windows), the file is actually fine! I understand the JVM might be different, but I am still lost. I've compiled in Java 1.5. JVMs are 1.6. The snippet which reads the file is below. public static ByteBuffer getAsByteArray(URL url) throws IOException { ByteArrayOutputStream tmpOut = new ByteArrayOutputStream(); URLConnection connection = url.openConnection(); int contentLength = connection.getContentLength(); InputStream in = url.openStream(); byte[] buf = new byte[512]; int len; while (true) { len = in.read(buf); if (len == -1) { break; } tmpOut.write(buf, 0, len); } tmpOut.close(); ByteBuffer bb = ByteBuffer.wrap(tmpOut.toByteArray(), 0, tmpOut.size()); //Lines below used to test if file is corrupt //FileOutputStream fos = new FileOutputStream("C:\\abc.pdf"); //fos.write(tmpOut.toByteArray()); return bb; } I must be missing something, and I've been banging my head trying to figure it out. Any help is greatly appreciated. Thanks. Edit: To further clarify my situation, the difference in the file before I read then with the snippet and after, is that the ones I output after reading are significantly smaller than they originally are. When opening them, they are not recognized as .pdf files. There are no exceptions being thrown that I ignore, and I have tried flushing to no avail. This snippet works in Safari, meaning the files are read in it's entirety, with no difference in size, and can be opened with any .pdf reader. In IE and Firefox, the files always end up being corrupted, consistently the same smaller size. I monitored the len variable (when reading a 59kb file), hoping to see how many bytes get read in at each loop. In IE and Firefox, at 18kb, the in.read(buf) returns a -1 as if the file has ended. Safari does not do this. I'll keep at it, and I appreciate all the suggestions so far.

  Read the article

• Exposing C# COM server events to Delphi client applications

  - by hectorsosajr

  My question is very similar to these two: http://stackoverflow.com/questions/1140984/c-component-events http://stackoverflow.com/questions/1638372/c-writing-a-com-server-events-not-firing-on-client However, what worked for them is not working for me. The type library file, does not have any hints of events definitions, so Delphi doesn't see it. The class works fine for other C# applications, as you would expect. COM Server tools: Visual Studio 2010 .NET 4.0 Delphi applications: Delphi 2010 Delphi 7 Here's a simplified version of the code: /// <summary> /// Call has arrived delegate. /// </summary> [ComVisible(false)] public delegate void CallArrived(object sender, string callData); /// <summary> /// Interface to expose SimpleAgent events to COM /// </summary> [ComVisible(true)] [GuidAttribute("1FFBFF09-3AF0-4F06-998D-7F4B6CB978DD")] [InterfaceType(ComInterfaceType.InterfaceIsIDispatch)] public interface IAgentEvents { ///<summary> /// Handles incoming calls from the predictive manager. ///</summary> ///<param name="sender">The class that initiated this event</param> ///<param name="callData">The data associated with the incoming call.</param> [DispId(1)] void OnCallArrived(object sender, string callData); } /// <summary> /// Represents the agent side of the system. This is usually related to UI interactions. /// </summary> [ComVisible(true)] [GuidAttribute("EF00685F-1C14-4D05-9EFA-538B3137D86C")] [ClassInterface(ClassInterfaceType.None)] [ComSourceInterfaces(typeof(IAgentEvents))] public class SimpleAgent { /// <summary> /// Occurs when a call arrives. /// </summary> public event CallArrived OnCallArrived; public SimpleAgent() {} public string AgentName { get; set; } public string CurrentPhoneNumber { get; set; } public void FireOffCall() { if (OnCallArrived != null) { OnCallArrived(this, "555-123-4567"); } } } The type library file has the definitions for the properties and methods, but no events are visible. I even opened the type library in Delphi's viewer to make sure. The Delphi app can see and use any property, methods, and functions just fine. It just doesn't see the events. I would appreciate any pointers or articles to read. Thanks!

  Read the article

• WordPress Write Cache Problem with Multiple Sessions

  - by Volomike

  I'm working on a content dripper custom plugin in WordPress that my client asked me to build. He says he wants it to catch a page view event, and if it's the right time of day (24 hours since last post), to pull from a resource file and output another post. He needed it to also raise a flag and prevent other sessions from firing that same snippet of code. So, raise some kind of flag saying, "I'm posting that post, go away other process," and then it makes that post and releases the flag again. However, the strangest thing is occurring when placed under load with multiple sessions hitting the site with page views. It's firing instead of one post -- it's randomly doing like 1, 2, or 3 extra posts, with each one thinking that it was the right time to post because it was 24 hours past the time of the last post. Because it's somewhat random, I'm guessing that the problem is some kind of write caching where the other sessions don't see the raised flag just yet until a couple microseconds pass. The plugin was raising the "flag" by simply writing to the wp_options table with the update_option() API in WordPress. The other user sessions were supposed to read that value with get_option() and see the flag, and then not run that piece of code that creates the post because a given session was already doing it. Then, when done, I lower the flag and the other sessions continue as normal. But what it's doing is letting those other sessions in. To make this work, I was using add_action('loop_start','checkToAddContent'). The odd thing about that function though is that it's called more than once on a page, and in fact some plugins may call it. I don't know if there's a better event to hook. Even still, even if I find an event to hook that only runs once on a page view, I still have multiple sessions to contend with (different users who may view the page at the same time) and I want only one given session to trigger the content post when the post is due on the schedule. I'm wondering if there are any WordPress plugin devs out there who could suggest another event hook to latch on to, and to figure out another way to raise a flag that all sessions would see. I mean, I could use the shared memory API in PHP, but many hosting plans have that disabled. Can't use a cookie or session var because that's only one single session. About the only thing that might work across hosting plans would be to drop a file as a flag, instead. If the file is present, then one session has the flag. If the file is not present, then other sessions can attempt to get the flag. Sure, I could use the file route, but it's kind of immature in my opinion and I was wondering if there's something in WordPress I could do.

  Read the article

• More GCC link time issues: undefined reference to main

  - by vikramtheone

  Hi Guys, I'm writing software for a Cortex-A8 processor and I have to write some ARM assembly code to access specific registers. I'm making use of the gnu compilers and related tool chains, these tools are installed on the processor board(Freescale i.MX515) with Ubuntu. I make a connection to it from my host PC(Windows) using WinSCP and the PuTTY terminal. As usual I started with a simple C project having main.c and functions.s. I compile the main.c using GCC, assemble the functions.s using as and link the generated object files using once again GCC, but I get strange errors during this process. An important finding - Meanwhile, I found out that my assembly code may have some issues because when I individually assemble it using the command as -o functions.o functions.s and try running the generated functions.o using ./functions.o command, the bash shell is failing to recognize this file as an executable(on pressing tab functions.o is not getting selected/PuTTY is not highlighting the file). Can anyone suggest whats happening here? Are there any specific options I have to send, to GCC during the linking process? The errors I see are strange and beyond my understanding, I don't understand to what the GCC is referring. I'm pasting here the contents of main.c, functions.s, the Makefile and the list of errors. Help, please!!! Vikram main.c #include <stdio.h> #include <stdlib.h> int main(void) { puts("!!!Hello World!!!"); /* prints !!!Hello World!!! */ return EXIT_SUCCESS; } functions.s * Main program */ .equ STACK_TOP, 0x20000800 .text .global _start .syntax unified _start: .word STACK_TOP, start .type start, function start: movs r0, #10 movs r1, #0 .end Makefile all: hello hello: main.o functions.o gcc -o main.o functions.o main.o: main.c gcc -c -mcpu=cortex-a8 main.c functions.o: functions.s as -mcpu=cortex-a8 -o functions.o functions.s Errors ubuntu@ubuntu-desktop:~/Documents/Project/Others/helloworld$ make gcc -c -mcpu=cortex-a8 main.c as -mcpu=cortex-a8 -o functions.o functions.s gcc -o main.o functions.o functions.o: In function `_start': (.text+0x0): multiple definition of `_start' /usr/lib/gcc/arm-linux-gnueabi/4.3.3/../../../crt1.o:init.c:(.text+0x0): first defined here /usr/lib/gcc/arm-linux-gnueabi/4.3.3/../../../crt1.o: In function `_start': init.c:(.text+0x30): undefined reference to `main' collect2: ld returned 1 exit status make: *** [hello] Error 1

  Read the article

• Boggling Direct3D9 dynamic vertex buffer Lock crash/post-lock failure on Intel GMA X3100.

  - by nj

  Hi, For starters I'm a fairly seasoned graphics programmer but as wel all know, everyone makes mistakes. Unfortunately the codebase is a bit too large to start throwing sensible snippets here and re-creating the whole situation in an isolated CPP/codebase is too tall an order -- for which I am sorry, do not have the time. I'll do my best to explain. B.t.w, I will of course supply specific pieces of code if someone wonders how I'm handling this-or-that! As with all resources in the D3DPOOL_DEFAULT pool, when the device context is taken away from you you'll sooner or later will have to reset your resources. I've built a mechanism to handle this for all relevant resources that's been working for years; but that fact nothingwithstanding I've of course checked, asserted and doubted any assumption since this bug came to light. What happens is as follows: I have a rather large dynamic vertex buffer, exact size 18874368 bytes. This buffer is locked (and discarded fully using the D3DLOCK_DISCARD flag) each frame prior to generating dynamic geometry (isosurface-related, f.y.i) to it. This works fine, until, of course, I start to reset. It might take 1 time, it might take 2 or it might take 5 resets to set off a bug that causes an access violation either on the pointer returned by the Lock() operation on the renewed resource or a plain crash -- regarding a somewhat similar address, but without the offset that it has tacked on to it in the first case because in that case we're somewhere halfway writing -- iside the D3D9 dll Lock() call. I've tested this on other hardware, upgraded my GMA X3100 drivers (using a MacBook with BootCamp) to the latest ones, but I can't reproduce it on any other machine and I'm at a loss about what's wrong here. I have tried to reproduce a similar situation with a similar buffer (I've got a large scratch pad of the same type I filled with quads) and beyond a certain amount of bytes it started to behave likewise. I'm not asking for a solution here but I'm very interested if there are other developers here who have battled with the same foe or maybe some who can point me in some insightful direction, maybe ask some questions that might shed a light on what I may or may not be overlooking. Another interesting artifact is that the vertex buffer starts to bug if I supply both D3DLOCK_DISCARD and D3DLOCK_NOOVERWRITE together which, even though not very logical (you're not going to overwrite if you've just discarded all), gives graphics glitches. Thanks and any corrections are more than welcome. Niels p.s - A friend of mine raised the valid point that it is a huge buffer for onboard video RAM and it's being at least double or triple buffered internally due to it's dynamic nature. On the other hand, the debug output (D3D9 debug DLL + max. warning output) remains silent. p.s 2 - Had it tested on more machines and still works -- it's probably a matter of circumstance: the huge dynamic, internally double/trippled buffered buffer, not a lot of memory and drivers that don't complain when they should.. Unless someone has a better suggestion; I'd still love to hear it :)

  Read the article

• Prevent SQL Injection in Dynamic column names

  - by Mr Shoubs

  I can't get away without writing some dynamic sql conditions in a part of my system (using Postgres). My question is how best to avoid SQL Injection with the method I am currently using. EDIT (Reasoning): There are many of columns in a number of tables (a number which grows (only) and is maintained elsewhere). I need a method of allowing the user to decide which (predefined) column they want to query (and if necessary apply string functions to). The query itself is far too complex for the user to write themselves, nor do they have access to the db. There are 1000's of users with varying requirements and I need to remain as flexible as possible - I shouldn't have to revisit the code unless the main query needs to change - Also, there is no way of knowing what conditions the user will need to use. I have objects (received via web service) that generates a condition (the generation method is below - it isn't perfect yet) for some large sql queries. The _FieldName is user editable (parameter name was, but it didn't need to be) and I am worried it could be an attack vector. I put double quotes (see quoted identifier) around the field name in an attempt to sanitize the string, this way it can never be a key word. I could also look up the field name against a list of fields, but it would be difficult to maintain on a timely basis. Unfortunately the user must enter the condition criteria, I am sure there must be more I can add to the sanatize method? and does quoting the column name make it safe? (my limited testing seems to think so). an example built condition would be "AND upper(brandloaded.make) like 'O%' and upper(brandloaded.make) not like 'OTHERBRAND'" ... Any help or suggestions are appreciated. Public Function GetCondition() As String Dim sb As New Text.StringBuilder 'put quote around the table name in an attempt to prevent some sql injection 'http://www.postgresql.org/docs/8.2/static/sql-syntax-lexical.html sb.AppendFormat(" {0} ""{1}"" ", _LogicOperator.ToString, _FieldName) Select Case _ConditionOperator Case ConditionOperatorOptions.Equals sb.Append(" = ") ... End Select sb.AppendFormat(" {0} ", Me.UniqueParameterName) 'for parameter Return Me.Sanitize(sb) End Function Private Function Sanitize(ByVal sb As Text.StringBuilder) As String 'compare against a similar blacklist mentioned here: http://forums.asp.net/t/1254125.aspx sb.Replace(";", "") sb.Replace("'", "") sb.Replace("\", "") sb.Replace(Chr(8), "") Return sb.ToString End Function Public ReadOnly Property UniqueParameterName() As String Get Return String.Concat(":" _UniqueIdentifier) End Get End Property

  Read the article

• Complex relationship between tables in NHibernate

  - by Ilya Kogan

  Hi all, I'm writing a Fluent NHibernate mapping for a legacy Oracle database. The challenge is that the tables have composite primary keys. If I were at total freedom, I would redesign the relationships and auto-generate primary keys, but other applications must write to the same database and read from it, so I cannot do it. These are the two tables I'll focus on: Example data Trips table: 1, 10:00, 11:00 ... 1, 12:00, 15:00 ... 1, 16:00, 19:00 ... 2, 12:00, 13:00 ... 3, 9:00, 18:00 ... Faults table: 1, 13:00 ... 1, 23:00 ... 2, 12:30 ... In this case, vehicle 1 made three trips and has two faults. The first fault happened during the second trip, and the second fault happened while the vehicle was resting. Vehicle 2 had one trip, during which a fault happened. Constraints Trips of the same vehicle never overlap. So the tables have an optional one-to-many relationship, because every fault either happens during a trip or it doesn't. If I wanted to join them in SQL, I would write: select ... from Faults left outer join Trips on Faults.VehicleId = Trips.VehicleId and Faults.FaultTime between Trips.TripStartTime and Trips.TripEndTime and then I'd get a dataset where every fault appears exactly once (one-to-many as I said). Note that there is no Vehicles table, and I don't need one. But I did create a view that contains all VehicleIds from both tables, so I can use it as a junction table. What am I actually looking for? The tables are huge because they cover years of data, and every time I only need to fetch a range of a few hours. So I need a mapping and a criteria that will run something like the following SQL underneath: select ... from Faults left outer join Trips on Faults.VehicleId = Trips.VehicleId and Faults.FaultTime between Trips.TripStartTime and Trips.TripEndTime where Faults.FaultTime between :p0 and :p1 Do you have any ideas how to achieve it? Note 1: Currently the application shouldn't write to the database, so persistence is not a must, although if the mapping supports persistence, it may help at some point in the future. Note 2: I know it's a tough one, so if you give me a great answer, you will be properly rewarded :) Thank you for reading this long question, and now I only hope for the best :)

  Read the article

• iPhone dev: load a file from resource folder

  - by thomax

  I'm writing an iPhone app with a UIWebView which should display various html files I have in the app resource folder. In xcode my project overview, these html files are displayed like this: dirA |---> index.html |---> a1.html |---> a2.html |---> my.css |---> dirB |---> b1.html |---> b2.html |---> dirC |---> c1.html |---> c2.html These resources where added to the project as such: - Checked "Copy items into destination groups folder (if needed)". - Reference type: Default. - Text encoding: Unicode (utf-8). - Recursively create groups for any added folders. The links in my html are relative, meaning they look like this: <a href="a1.html">a2</a> <a href="a2.html">a2</a> <a href="dirB/b2.html">b2</a> <a href="dirC/c1.html">b2</a> In order to display the index.html when the app starts up, I use the following code: NSString *path = [[NSBundle mainBundle] pathForResource:@"index" ofType:@"html"]; NSURL *url = [NSURL fileURLWithPath:path]; NSURLRequest *request = [NSURLRequest requestWithURL:url]; [webView loadRequest:request]; This works fine. Following links from the index file also works fine, as long as the html files requested are directly under dirA. If the link followed points to a file in a sub-directory, then didFailLoadWithError will catch the situation and report that the requested file does not exist. Note that [webView loadHtmlString:myHtml]; cannot be part of the solution, as I need back and forward buttons to work in my web view. So the question is: How can I follow a relative link to an html file in a sub directory within my resources? I've been all over stackoverflow and the rest of the tubes for the past few days trying to figure this one out, but nowhere have I come across the solution to this exact problem. Any insight at all would be very, very much appreciated!

  Read the article

• What's the best way to do base36 arithmetic in perl?

  - by DVK

  What's the best way to do base36 arithmetic in Perl? To be more specific, I need to be able to do the following: Operate on positive N-digit numbers in base 36 (e.g. digits are 0-9 A-Z) N is finite, say 9 Provide basic arithmetic, at the very least the following 3: Addition (A+B) Subtraction (A-B) Whole division, e.g. floor(A/B). Strictly speaking, I don't really need a base10 conversion ability - the numbers will 100% of time be in base36. So I'm quite OK if the solution does NOT implement conversion from base36 back to base10 and vice versa. I don't much care whether the solution is brute-force "convert to base 10 and back" or converting to binary, or some more elegant approach "natively" performing baseN operations (as stated above, to/from base10 conversion is not a requirement). My only 3 considerations are: It fits the minimum specifications above It's "standard". Currently we're using and old homegrown module based on base10 conversion done by hand that is buggy and sucks. I'd much rather replace that with some commonly used CPAN solution instead of re-writing my own bicycle from scratch, but I'm perfectly capable of building it if no better standard possibility exists. It must be fast-ish (though not lightning fast). Something that takes 1 second to sum up 2 9-digit base36 numbers is worse than anything I can roll on my own :) P.S. Just to provide some context in case people decide to solve my XY problem for me in addition to answering the technical question above :) We have a fairly large tree (stored in DB as a bunch of edges), and we need to superimpose order on a subset of that tree. The tree dimentions are big both depth- and breadth- wise. The tree is VERY actively updated (inserts and deletes and branch moves). This is currently done by having a second table with 3 columns: parent_vertex, child_vertex, local_order, where local_order is an 9-character string built of A-Z0-9 (e.g. base 36 number). Additional considerations: It is required that the local order is unique per child (and obviously unique per parent), Any complete re-ordering of a parent is somewhat expensive, and thus the implementation is to try and assign - for a parent with X children - the orders which are somewhat evenly distributed between 0 and 36**10-1, so that almost no tree inserts result in a full re-ordering.

  Read the article

• Java "compare cannot be resolved to a type" error

  - by King Triumph

  I'm getting a strange error when attempting to use a comparator with a binary search on an array. The error states that "compareArtist cannot be resolved to a type" and is thrown by Eclipse on this code: Comparator<Song> compare = new Song.compareArtist(); I've done some searching and found references to a possible bug with Eclipse, although I have tried the code on a different computer and the error persists. I've also found similar issues regarding the capitalization of the compare method, in this case compareArtist. I've seen examples where the first word in the method name is capitalized, although it was my understanding that method names are traditionally started with a lower case letter. I have experimented with changing the capitalization but nothing has changed. I have also found references to this error if the class doesn't import the correct package. I have imported java.util in both classes in question, which to my knowledge allows the use of the Comparator. I've experimented with writing the compareArtist method within the class that has the binary search call as well as in the "Song" class, which according to my homework assignment is where it should be. I've changed the constructor accordingly and the issue persists. Lastly, I've attempted to override the Comparator compare method by implementing Comparator in the Song class and creating my own method called "compare". This returns the same error. I've only moved to calling the comparator method something different than "compare" after finding several examples that do the same. Here is the relevant code for the class that calls the binary search that uses the comparator. This code also has a local version of the compareArtist method. While it is not being called currently, the code for this method is the same as the in the class Song, where I am trying to call it from. Thanks for any advice and insight. import java.io.*; import java.util.*; public class SearchByArtistPrefix { private Song[] songs; // keep a direct reference to the song array private Song[] searchResults; // holds the results of the search private ArrayList<Song> searchList = new ArrayList<Song>(); // hold results of search while being populated. Converted to searchResults array. public SearchByArtistPrefix(SongCollection sc) { songs = sc.getAllSongs(); } public int compareArtist (Song firstSong, Song secondSong) { return firstSong.getArtist().compareTo(secondSong.getArtist()); } public Song[] search(String artistPrefix) { String artistInput = artistPrefix; int searchLength = artistInput.length(); Song searchSong = new Song(artistInput, "", ""); Comparator<Song> compare = new Song.compareArtist(); int search = Arrays.binarySearch(songs, searchSong, compare);

  Read the article

• Understanding CLR 2.0 Memory Model

  - by Eloff

  Joe Duffy, gives 6 rules that describe the CLR 2.0+ memory model (it's actual implementation, not any ECMA standard) I'm writing down my attempt at figuring this out, mostly as a way of rubber ducking, but if I make a mistake in my logic, at least someone here will be able to catch it before it causes me grief. Rule 1: Data dependence among loads and stores is never violated. Rule 2: All stores have release semantics, i.e. no load or store may move after one. Rule 3: All volatile loads are acquire, i.e. no load or store may move before one. Rule 4: No loads and stores may ever cross a full-barrier (e.g. Thread.MemoryBarrier, lock acquire, Interlocked.Exchange, Interlocked.CompareExchange, etc.). Rule 5: Loads and stores to the heap may never be introduced. Rule 6: Loads and stores may only be deleted when coalescing adjacent loads and stores from/to the same location. I'm attempting to understand these rules. x = y y = 0 // Cannot move before the previous line according to Rule 1. x = y z = 0 // equates to this sequence of loads and stores before possible re-ordering load y store x load 0 store z Looking at this, it appears that the load 0 can be moved up to before load y, but the stores may not be re-ordered at all. Therefore, if a thread sees z == 0, then it also will see x == y. If y was volatile, then load 0 could not move before load y, otherwise it may. Volatile stores don't seem to have any special properties, no stores can be re-ordered with respect to each other (which is a very strong guarantee!) Full barriers are like a line in the sand which loads and stores can not be moved over. No idea what rule 5 means. I guess rule 6 means if you do: x = y x = z Then it is possible for the CLR to delete both the load to y and the first store to x. x = y z = y // equates to this sequence of loads and stores before possible re-ordering load y store x load y store z // could be re-ordered like this load y load y store x store z // rule 6 applied means this is possible? load y store x // but don't pop y from stack (or first duplicate item on top of stack) store z What if y was volatile? I don't see anything in the rules that prohibits the above optimization from being carried out. This does not violate double-checked locking, because the lock() between the two identical conditions prevents the loads from being moved into adjacent positions, and according to rule 6, that's the only time they can be eliminated. So I think I understand all but rule 5, here. Anyone want to enlighten me (or correct me or add something to any of the above?)

  Read the article

• Scala actors: receive vs react

  - by jqno

  Let me first say that I have quite a lot of Java experience, but have only recently become interested in functional languages. Recently I've started looking at Scala, which seems like a very nice language. However, I've been reading about Scala's Actor framework in Programming in Scala, and there's one thing I don't understand. In chapter 30.4 it says that using react instead of receive makes it possible to re-use threads, which is good for performance, since threads are expensive in the JVM. Does this mean that, as long as I remember to call react instead of receive, I can start as many Actors as I like? Before discovering Scala, I've been playing with Erlang, and the author of Programming Erlang boasts about spawning over 200,000 processes without breaking a sweat. I'd hate to do that with Java threads. What kind of limits am I looking at in Scala as compared to Erlang (and Java)? Also, how does this thread re-use work in Scala? Let's assume, for simplicity, that I have only one thread. Will all the actors that I start run sequentially in this thread, or will some sort of task-switching take place? For example, if I start two actors that ping-pong messages to each other, will I risk deadlock if they're started in the same thread? According to Programming in Scala, writing actors to use react is more difficult than with receive. This sounds plausible, since react doesn't return. However, the book goes on to show how you can put a react inside a loop using Actor.loop. As a result, you get loop { react { ... } } which, to me, seems pretty similar to while (true) { receive { ... } } which is used earlier in the book. Still, the book says that "in practice, programs will need at least a few receive's". So what am I missing here? What can receive do that react cannot, besides return? And why do I care? Finally, coming to the core of what I don't understand: the book keeps mentioning how using react makes it possible to discard the call stack to re-use the thread. How does that work? Why is it necessary to discard the call stack? And why can the call stack be discarded when a function terminates by throwing an exception (react), but not when it terminates by returning (receive)? I have the impression that Programming in Scala has been glossing over some of the key issues here, which is a shame, because otherwise it's a truly excellent book.

  Read the article

• SimpleXML SOAP response Namespace issues

  - by Stu

  Hi. After spending SEVERAL frustrated hours on this I am asking for your help. I am trying to get the content of particular nodes from a SOAP response. The response is $XmlStr = <?xml version="1.0" encoding="UTF-8"?><env:Envelope xmlns:env="http://www.w3.org/2003/05/soap-envelope"<xmlns:ns1="http://soap.xxxxxx.co.uk/"><env:Body><ns1:PlaceOrderResponse><xxxxxOrderNumber></xxxxxOrderNumber><ErrorArray><Error><ErrorCode>24</ErrorCode><ErrorText>The+client+order+number+3002254+is+already+in+use</ErrorText></Error><Error><ErrorCode>1</ErrorCode><ErrorText>Aborting</ErrorText></Error></ErrorArray></ns1:PlaceOrderResponse></env:Body></env:Envelope> I am trying to get at the nodes and children of <ErrorArray. Because of the XML containing namespaces $XmlArray = new SimpleXMLElement($XmlStr); foreach ($XmlArray->env:Envelope->env:Body->ns1:PlaceOrderResponse->ErrorArray->Error as $Error) { echo $Error->ErrorCode."<br />";<br /> } doesn't work. I have read a number of articles such as http://www.sitepoint.com/blogs/2005/10/20/simplexml-and-namespaces/ htp://blog.stuartherbert.com/php/2007/01/07/using-simplexml-to-parse-rss-feeds/ and about 20 questions on this site which unfortunately are not helping. (the second link has htp:// as a newbie here I cannot post more than one link) Even writing, $XmlArray = new SimpleXMLElement($XmlStr); echo "<br /><br /><pre>\n"; print_r($XmlArray); echo "<pre><br /><br />\n"; gives SimpleXMLElement Object ( ) which makes me wonder if the soap response ($XmlStr) is actually a valid input for SimpleXMLElement. It seems that the line $XmlArray = new SimpleXMLElement($XmlStr); is not doing what I expect it to. Any help on how to get the nodes from the XML above would be very welcome. Obviously getting it to work (having a working example) is what I need in the short term, but if someone could help me understand what I am doing wrong would be better in the long term. Cheers. Stu

  Read the article

< Previous Page | 627 628 629 630 631 632 633 634 635 636 637 638  | Next Page >