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  • OJB Reference Descriptor 1:0 relationship? Should I set auto-retrieve to false?

    - by godzillasdm
    Hi, I am having an issue while using Apache OJB with Spring 2 inside my web app. I'm using OJB reference-descriptor with 2 foreign key properties. I have an object A (parent) and object B (referenced object). The thing is, for an object A, there may or may not be an object B. In the case where there is no object B to go with Object A, the object B seems to be instantiated (through Spring?) anyways. However, I am unable to access object B's members. Whenever I test if Object B == null, it always returns false even though there is no matching value in the database. Since this Object is never null, I figured I can test the object's member like so: if( objectb.getDocumentNumber == null) { return false; } However, I get an exception in the jsp: javax.servlet.jsp.el.ELException: An error occurred while getting property "documentNumber" from an instance class org.sample.pojo.Objectb$$EnhancerByCGLIB$$78022a2 and this exception in the debugger when it's creating the objectB: com.sun.jdi.InvocationException occurred invoking method. I am guessing that the reference-descriptor must be a 1:1+ relationship, instead of a 1:0+ relationship. I was wondering if I should set the property 'auto-retrieve' to false, and then use the PersistenceBroker.retrieveAllReferences(Object obj); method as directed. However, this method's return value is 'void', so I am guessing that Spring somehow creates, and sets the reference class for me. (Returning me back to the same issue I'm having.) I will need a way to test whether the reference object exists first. If not, don't call this retrieveAllReferences method, but I don't see how. Am I going about this all wrong? Does reference-descriptor not allow 1:0 relations? Any work around to my problem? Your suggestions are greatly appreciated!

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  • Is having 'Util' classes a cause for concern? [closed]

    - by Matt Fenwick
    I sometimes create 'Util' classes which primarily serve to hold methods and values that don't really seem to belong elsewhere. But every time I create one of these classes, I think "uh-oh, I'm gonna regret this later ...", because I read somewhere that it's bad. But on the other hand, there seem to be two compelling (at least for me) cases for them: implementation secrets that are used in multiple classes within a package providing useful functionality to augment a class, without cluttering its interface Am I on the way to destruction? What you say !! Should I refactor?

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  • How to dispose of a NET COM interop object on Release()

    - by mhenry1384
    I have a COM object written in managed code (C++/CLI). I am using that object in standard C++. How do I force my COM object's destructor to be called immediately when the COM object is released? If that's not possible, call I have Release() call a MyDispose() method on my COM object? My code to declare the object (C++/CLI): [Guid("57ED5388-blahblah")] [InterfaceType(ComInterfaceType::InterfaceIsIDispatch)] [ComVisible(true)] public interface class IFoo { void Doit(); }; [Guid("417E5293-blahblah")] [ClassInterface(ClassInterfaceType::None)] [ComVisible(true)] public ref class Foo : IFoo { public: void MyDispose(); ~Foo() {MyDispose();} // This is never called !Foo() {MyDispose();} // This is called by the garbage collector. virtual ULONG Release() {MyDispose();} // This is never called virtual void Doit(); }; My code to use the object (native C++): #import "..\\Debug\\Foo.tlb" ... Bar::IFoo setup(__uuidof(Bar::Foo)); // This object comes from the .tlb. setup.Doit(); setup-Release(); // explicit release, not really necessary since Bar::IFoo's destructor will call Release(). If I put a destructor method on my COM object, it is never called. If I put a finalizer method, it is called when the garbage collector gets around to it. If I explicitly call my Release() override it is never called. I would really like it so that when my native Bar::IFoo object goes out of scope it automatically calls my .NET object's dispose code. I would think I could do it by overriding the Release(), and if the object count = 0 then call MyDispose(). But apparently I'm not overriding Release() correctly because my Release() method is never called. Obviously, I can make this happen by putting my MyDispose() method in the interface and requiring the people using my object to call MyDispose() before Release(), but it would be slicker if Release() just cleaned up the object. Is it possible to force the .NET COM object's destructor, or some other method, to be called immediately when a COM object is released? Googling on this issue gets me a lot of hits telling me to call System.Runtime.InteropServices.Marshal.ReleaseComObject(), but of course, that's how you tell .NET to release a COM object. I want COM Release() to Dispose of a .NET object.

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  • How do I add values to semi-complex JSON object?

    - by Nick Verheijen
    I'm fairly new to using JSON objects and I'm kinda stuck. I've got an JSON object that was converted from this array: Array ( [status] => success [id] => 1 [name] => Zone 1 [description] => Awesome zone deze.. [tiles] => Array ( // Column for the tile grid [0] => Array ( // Row for the tile grid [0] => Array ( [tileID] => 1 [rotation] => 0 ) [1] => Array ( [tileID] => 1 [rotation] => 0 ) // Etc.. ) [1] => Array // etc.. etc.. ) ) I use this object to render out an isometric grid for my HTML5 Canvas game. I'm building a map editor and to put more tiles on the map, i'll have to add values to this json object. This is how I would do it in PHP: mapData[column][row] = array( 'tileID' => 1, 'rotation' => 0 ); So my question is, how do I achieve this with a JSON object in javascript? Thanks in advance! Nick Update I've ran into an error: can't convert undefined to object mapDataTiles[mouseY][mouseX] = { tileID: editorSelectedTile, rotation: 0 }; This is the code i use for clicking & then saving the new tile to the JSON object. At first I though that one of my parameters was 'undefined', so i logged those to the console but they came out perfectly.. // If there is already a tile placed on these coordinates if( mapDataTiles[mouseX] && mapDataTiles[mouseX][mouseY] ) { mapDataTiles[mouseX][mouseY]['tileID'] = editorSelectedTile; } // If there is no tile placed on these coordinates else { mapDataTiles[mouseX][mouseY] = { tileID: editorSelectedTile, rotation: 0 }; } My variables have the following values: MouseX: 5 MouseY: 17 tileID: 2 Also weird fact, that for some coordinates it does actually work and save new data to the array. mapDataTiles[mouseY][mouseX] = { tileID: editorSelectedTile, rotation: 0 };

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  • How to include all objects of an archive in a shared object?

    - by Didier Trosset
    When compiling our project, we create several archives (static libraries), say liby.a and libz.a that each contains an object file defining a function y_function() and z_function(). Then, these archives are joined in a shared object, say libyz.so, that is one of our main distributable target. g++ -fPIC -c -o y.o y.cpp ar cr liby.a y.o g++ -fPIC -c -o z.o z.cpp ar cr libz.a z.o g++ -shared -L. -ly -lz -o libyz.so When using this shared object into the example program, say x.c, the link fails because of an undefined references to functions y_function() and z_function(). g++ x.o -L. -lyz -o xyz It works however when I link the final executable directly with the archives (static libraries). g++ x.o -L. -ly -lz -o xyz My guess is that the object files contained in the archives are not linked into the shared library because they are not used in it. How to force inclusion? Edit: Inclusion can be forced using --whole-archive ld option. But if results in compilation errors: g++ -shared '-Wl,--whole-archive' -L. -ly -lz -o libyz.so /usr/lib/libc_nonshared.a(elf-init.oS): In function `__libc_csu_init': (.text+0x1d): undefined reference to `__init_array_end' /usr/bin/ld: /usr/lib/libc_nonshared.a(elf-init.oS): relocation R_X86_64_PC32 against undefined hidden symbol `__init_array_end' can not be used when making a shared object /usr/bin/ld: final link failed: Bad value Any idea where this comes from?

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  • How do I set a flash object to open a url in a new window?

    - by Keith Donegan
    Hi Guys, I have this code: <object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=9,0,28,0" width="300" height="250"> <param name="movie" value="Spotify_premium_300x250.swf" /> <param name="quality" value="high" /> <embed src="Spotify_premium_300x250.swf" quality="high" pluginspage="http://www.adobe.com/shockwave/download/download.cgi?P1_Prod_Version=ShockwaveFlash" type="application/x-shockwave-flash" width="300" height="250"></embed> </object> EDIT: Code from Tom <object onclick="javascript: window.open('http://www.stackoverflow.com', _blank, 'width=1024, height=600, menubar=no, resizable=yes');" classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=9,0,28,0" width="300" height="250"> <param name="movie" value="Spotify_premium_300x250.swf" /> <param name="quality" value="high" /> <embed src="Spotify_premium_300x250.swf" quality="high" pluginspage="http://www.adobe.com/shockwave/download/download.cgi?P1_Prod_Version=ShockwaveFlash" type="application/x-shockwave-flash" width="300" height="250"></embed> </object> I would like it as when a user clicks the flash object, it's opens a URL in a new window. How would I go about doing this? Cheers, Keith

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  • Optimal way to generate list of PHP object properties with delimiter character, implode()?

    - by Kris
    I am trying to find out if there is a more optimal way for creating a list of an object's sub object's properties. (Apologies for the crude wording, I am not really much of an OO expert) I have an object "event" that has a collection of "artists", each artist having an "artist_name". On my HTML output, I want a plain list of artist names delimited by a comma. PHP's implode() seems to be the best way to create a comma delimited list of values. I am currently iterating through the object and push values in a temporary array "artistlist" so I can use implode(). That is the shortest I could come up with. Is there a way to do this more elegant? $artistlist = array(); foreach ($event->artists as $artist) { $artistlist[] = $artist->artist_name; } echo implode(', ', $artistlist);

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  • How do you test a command object in a grails controller integration test?

    - by egervari
    I'm new to grails. How do I test a form command object to make sure that it's working? Here's some setup code in a test. When I try to do it, I get the following exceptions: Error occurred creating command object. org.codehaus.groovy.grails.web.servlet.mvc.exceptions.ControllerExecutionException: Error occurred creating command object. at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) .... Caused by: groovy.lang.MissingPropertyException: No such property: password for class: project.user.RegistrationForm Possible solutions: password Here is my test case. As you can see, I set "password" on the params map... void testSaveWhenDataIsCorrect() { controller.params.emailAddress = "[email protected]" controller.params.password = "secret" controller.params.confirmPassword = "secret" controller.save() assertEquals "success", redirectArgs.view ... } Here's the controller action, that adds the command object as a closure parameter: def save = { RegistrationForm form -> if(form.hasErrors()) { render view: "create", model: [form: form] } else { def user = new User(form.properties) user.password = form.encryptedPassword if(user.save()) { redirect(action: "success") } else { render view: "create", model: [form: form] } } } Here's the command object itself... and note that it DOES have a "password" field... class RegistrationForm { def springSecurityService String emailAddress String password String confirmPassword String getEncryptedPassword() { springSecurityService.encodePassword(password) } static constraints = { emailAddress(blank: false, email: true) password(blank: false, size:4..10) confirmPassword(blank: false, validator: { password != confirmPassword }) } } I'm totally lost in the non-intuitive way to do controllers... Please help.

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  • How can I use html/javascript to make <a> link trigger an embedded flash object?

    - by MikeN
    Using HTML/Javascript I want to make an link trigger a flash object that is normally triggered by clicking on the flash itself. The flash objects is actually the "Call Me Now" button from Google Voice which looks something like: <object type="application/x-shockwave-flash" data="https://clients4.google.com/voice/embed/webCallButton" width="230" height="85"> <param name="movie" value="https://clients4.google.com/voice/embed/webCallButton"/> <param name="wmode" value="transparent" /><param name="FlashVars" /> </object> When you click on the object the first time it brings up a set of fields to enter your phone number in to make the call. So I want to be able to trigger that action by having a user click on a different link (which would actually be the phone number that the widget would call.)

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  • Can I change class types in a setter with an object-oriented language?

    - by user214626
    Hello, Here is the problem statement : Calling a setter on the object should result in the object to change to an object of a different class, which language can support this ? Ex. I have a class called "Man" (Parent Class), and two children namely "Toddler" and "Old Man", they are its children because they override a behaviour in Man called as walk.( i.e Toddler sometimes walks using both his hands and legs kneeled down and the Old man uses a stick to support himself). The Man class has a attribute called age, I have a setter on Man,say it is called setAge(int ageValue). I have 3 objects, 2 toddlers, 1 old-Man. (The system is up and running,i guess when we say objects it is obvious) .I will make this call, toddler.setAge(80), I expect the toddler to change to an object of type Old Man. Is this possible.Please suggest. Thanks,

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  • how to specify which child class this object belong to after retrieving from a hashmap?

    - by chandra wibowo
    hi everyone, i have a parent class called Course, and two child class PostgradCourse and UndergradCourse. i have a hashmap HashMap courses; i store all the postgradCourse and undergradCourse objects in the hashmap. i want to retrieve an undergradCourse object from the hashmap using the key. Course course = courses.get(courseCode); then i want to call a method in the UndergradCourse class, setUnits() method course.setUnits(); but the compiler say cannot find symbol- method setUnit() im pretty sure the problem is the compiler is looking for a method setUnit() in the Course class instead of UndergradCourse class i did this but its not working UndergradCourse course = courses.get(courseCode); results in incompatible type so how can i retrieve undergradCourse object from the hashmap as an undergradCourse object instead of course object? so then i can call a method inside the child class thanks in advance

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  • How Do I Import a 3D Object into Adobe Flex?

    - by Kim
    Hi everyone, I wanted to know if anyone here knows how to import a 3D Object (i.e. Maya 3D Model) into Adobe Flex Application? I needed to create a simple Flex application which will allow me to rotate the 3D Object by dragging but I cannot seem to start doing it because I'm having a hard time trying to figure out how I can import my 3D model into Flex. This is exactly what I wanted to do: 3D Object in Flex I hope someone can help me. Thanks a lot :)

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  • How can I return an object into PHP userspace from my extension?

    - by John Factorial
    I have a C++ object, Graph, which contains a property named cat of type Category. I'm exposing the Graph object to PHP in an extension I'm writing in C++. As long as the Graph's methods return primitives like boolean or long, I can use the Zend RETURN_*() macros (e.g. RETURN_TRUE(); or RETURN_LONG(123);. But how can I make Graph-getCategory(); return a Category object for the PHP code to manipulate? I'm following the tutorial over at http://devzone.zend.com/article/4486, and here's the Graph code I have so far: #include "php_getgraph.h" zend_object_handlers graph_object_handlers; struct graph_object { zend_object std; Graph *graph; }; zend_class_entry *graph_ce; #define PHP_CLASSNAME "WFGraph" ZEND_BEGIN_ARG_INFO_EX(php_graph_one_arg, 0, 0, 1) ZEND_END_ARG_INFO() ZEND_BEGIN_ARG_INFO_EX(php_graph_two_args, 0, 0, 2) ZEND_END_ARG_INFO() void graph_free_storage(void *object TSRMLS_DC) { graph_object *obj = (graph_object*)object; delete obj-graph; zend_hash_destroy(obj-std.properties); FREE_HASHTABLE(obj-std.properties); efree(obj); } zend_object_value graph_create_handler(zend_class_entry *type TSRMLS_DC) { zval *tmp; zend_object_value retval; graph_object *obj = (graph_object*)emalloc(sizeof(graph_object)); memset(obj, 0, sizeof(graph_object)); obj-std.ce = type; ALLOC_HASHTABLE(obj-std.properties); zend_hash_init(obj-std.properties, 0, NULL, ZVAL_PTR_DTOR, 0); zend_hash_copy(obj-std.properties, &type-default_properties, (copy_ctor_func_t)zval_add_ref, (void*)&tmp, sizeof(zval*)); retval.handle = zend_objects_store_put(obj, NULL, graph_free_storage, NULL TSRMLS_CC); retval.handlers = &graph_object_handlers; return retval; } PHP_METHOD(Graph, __construct) { char *perspectives; int perspectives_len; Graph *graph = NULL; zval *object = getThis(); if(zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &perspectives, &perspectives_len) == FAILURE) { RETURN_NULL(); } graph = new Graph(perspectives); graph_object *obj = (graph_object*)zend_object_store_get_object(object TSRMLS_CC); obj-graph = graph; } PHP_METHOD(Graph, hasCategory) { long perspectiveId; Graph *graph; graph_object *obj = (graph_object*)zend_object_store_get_object(getThis() TSRMLS_CC); graph = obj-graph; if (graph == NULL) { RETURN_NULL(); } if(zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "l", &perspectiveId) == FAILURE) { RETURN_NULL(); } RETURN_BOOL(graph-hasCategory(perspectiveId)); } PHP_METHOD(Graph, getCategory) { // what to do here? RETURN_TRUE; } function_entry php_getgraph_functions[] = { PHP_ME(Graph,__construct,NULL,ZEND_ACC_PUBLIC|ZEND_ACC_CTOR) PHP_ME(Graph,hasCategory,php_graph_one_arg,ZEND_ACC_PUBLIC) PHP_ME(Graph,getCategory,php_graph_one_arg,ZEND_ACC_PUBLIC) { NULL, NULL, NULL } }; PHP_MINIT_FUNCTION(getgraph) { zend_class_entry ce; INIT_CLASS_ENTRY(ce, PHP_CLASSNAME, php_getgraph_functions); graph_ce = zend_register_internal_class(&ce TSRMLS_CC); graph_ce-create_object = graph_create_handler; memcpy(&graph_object_handlers, zend_get_std_object_handlers(), sizeof(zend_object_handlers)); graph_object_handlers.clone_obj = NULL; return SUCCESS; } zend_module_entry getgraph_module_entry = { #if ZEND_MODULE_API_NO = 20010901 STANDARD_MODULE_HEADER, #endif PHP_GETGRAPH_EXTNAME, NULL, /* Functions */ PHP_MINIT(getgraph), NULL, /* MSHUTDOWN */ NULL, /* RINIT */ NULL, /* RSHUTDOWN */ NULL, /* MINFO */ #if ZEND_MODULE_API_NO = 20010901 PHP_GETGRAPH_EXTVER, #endif STANDARD_MODULE_PROPERTIES }; #ifdef COMPILE_DL_GETGRAPH extern "C" { ZEND_GET_MODULE(getgraph) } #endif

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  • An error occurred creating the form. See Exception.InnerException for details. The error is: Object

    - by Ben
    I get this error when attempting to debug my form, I cannot see where at all the error could be (also does not highlight where), anyone have any suggestions? An error occurred creating the form. See Exception.InnerException for details. The error is: Object reference not set to an instance of an object. Public Class Form1 Dim dateCrap As String = "Date:" Dim IPcrap As String = "Ip:" Dim pcCrap As String = "Computer:" Dim programCrap As String = "Program:" Dim textz As String = TextBox1.Text Dim sep() As String = {vbNewLine & vbNewLine} Dim sections() As String = Text.Split(sep, StringSplitOptions.None) Dim NewArray() As String = TextBox1.Text.Split(vbNewLine) Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click For i = 0 To sections.Count - 1 TextBox2.Text = sections(i) Dim text2 As String = TextBox2.Text Dim sep2() As String = {vbNewLine & vbNewLine} Dim sections2() As String = Text.Split(sep, StringSplitOptions.None) Dim FTPinfo() As String = TextBox2.Text.Split(vbNewLine) Dim clsRequest As System.Net.FtpWebRequest = _ DirectCast(System.Net.WebRequest.Create(sections2(0).Replace("Url/Host:", "")), System.Net.FtpWebRequest) clsRequest.Credentials = New System.Net.NetworkCredential(sections2(1).Replace("Login:", ""), (sections2(2).Replace("Password:", ""))) clsRequest.Method = System.Net.WebRequestMethods.Ftp.UploadFile ' read in file... Dim bFile() As Byte = System.IO.File.ReadAllBytes(txtShellDir.Text) ' upload file... Dim clsStream As System.IO.Stream = clsRequest.GetRequestStream() clsStream.Write(bFile, 0, bFile.Length) clsStream.Close() clsStream.Dispose() Next End Sub Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click ListBox1.Items.Clear() Dim fdlg As OpenFileDialog = New OpenFileDialog() fdlg.Title = "Browse for the FTP List you wish to use." fdlg.InitialDirectory = Application.ExecutablePath fdlg.Filter = "All files (*.txt)|*.txt|txt files (*.txt)|*.txt" fdlg.FilterIndex = 2 fdlg.RestoreDirectory = True If fdlg.ShowDialog() = DialogResult.OK Then 'ListBox1.Items.AddRange(Split(My.Computer.FileSystem.ReadAllText(fdlg.FileName), vbNewLine)) TextBox1.Text = My.Computer.FileSystem.ReadAllText(fdlg.FileName) End If Dim tmp() As String = TextBox1.Text.Split(CChar(vbNewLine)) For Each line As String In tmp If line.Length > 1 Then TextBox1.AppendText(line & vbNewLine) End If Next TextBox1.Text = TextBox1.Text.Replace(" ", "") TextBox1.Text = TextBox1.Text.Replace("----------------------------------------------------------", vbNewLine) For Each item As String In NewArray ListBox1.Items.Add(item) Next Try For i = 0 To ListBox1.Items.Count - 1 If ListBox1.Items(i).Contains(dateCrap) Then ListBox1.Items.RemoveAt(i) End If Next Catch ex As Exception End Try Try For i = 0 To ListBox1.Items.Count - 1 If ListBox1.Items(i).Contains(IPcrap) Then ListBox1.Items.RemoveAt(i) End If Next Catch ex As Exception End Try Try For i = 0 To ListBox1.Items.Count - 1 If ListBox1.Items(i).Contains(pcCrap) Then ListBox1.Items.RemoveAt(i) End If Next Catch ex As Exception End Try Try For i = 0 To ListBox1.Items.Count - 1 If ListBox1.Items(i).Contains(programCrap) Then ListBox1.Items.RemoveAt(i) End If Next Catch ex As Exception End Try TextBox1.Text = "" For Each thing As Object In ListBox1.Items TextBox1.AppendText(thing.ToString & vbNewLine) Next End Sub Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) For i = 0 To ListBox1.SelectedItems.Count - 1 TextBox1.Text = TextBox1.Text & ListBox1.Items.Item(i).ToString() & vbNewLine Next End Sub End Class

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  • How do I change the CSS from a web page contained in an object tag? (XHTML, jquery)

    - by Jose
    Hi! I've been having a bit of a problem with jQuery and XHTML. Basically, I've got an object tag that contains a Web Page in its data attribute. Now, what I want is that when I click a button I get this web page and dinamically change the CSS file it's currently using. I've tried to get the page by using jquery, but all I get is the object itself, not the webpage contained in the object. Thanks!! :)

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  • How does one get access to the Flash object's vars in IE?

    - by Tim
    Is there a way in IE Browsers to access the Flash object? In this case it is made with mootools swiff. It´s working fine in all other browsers, because they can wrap this object correctly. But it does not work in IE. Here is the script: var swfObj = $('mbImage').getElement('object'); swfObj.get('data'); <--- Thats not working in IE

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  • Loose typing not applied to objects

    - by TecBrat
    I have very little experience working with classes and object. I work in a loosely typed language, PHP. I was working with a SimpleXML object and ran into a problem where I was trying to do math with an element of that object like $results->ProductDetail->{'Net'.$i}; If I echoed that value, I'd get 0.53 but when I tried to do math with it, it was converted to 0 Is there a reason that a loosely typed language would not recognize that as a float and handle it as such? Why would "echo" handle it as a string but the math fail to convert it? Example: $xml='<?xml version="1.0" encoding="UTF-8" ?>'; $xml.='<Test> <Item> <Price>0.53</Price> </Item> </Test>'; $result=simplexml_load_string($xml); var_dump($result->Item->Price); echo '<br>'; echo $result->Item->Price; echo '<br>'; echo 1+$result->Item->Price; echo '<br>'; echo 1+(float)$result->Item->Price; Output: object(SimpleXMLElement)#4 (1) { [0]=> string(4) "0.53" } 0.53 1 1.53

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  • Game Messaging System Design

    - by you786
    I'm making a simple game, and have decided to try to implement a messaging system. The system basically looks like this: Entity generates message - message is posted to global message queue - messageManager notifies every object of the new message through onMessageReceived(Message msg) - if object wants, it acts on the message. The way I'm making message objects is like this: //base message class, never actually instantiated abstract class Message{ Entity sender; } PlayerDiedMessage extends Message{ int livesLeft; } Now my SoundManagerEntity can do something like this in its onMessageReceived() method public void messageReceived(Message msg){ if(msg instanceof PlayerDiedMessage){ PlayerDiedMessage diedMessage = (PlayerDiedMessage) msg; if(diedMessage.livesLeft == 0) playSound(SOUND_DEATH); } } The pros to this approach: Very simple and easy to implement The message can contain as much as information as you want, because you can just create a new Message subclass that has whatever info necessary. The cons: I can't figure out how I can recycle Message objects to a object pool, unless I have a different pool for each subclass of Message. So I have lots and lots of object creation/memory allocation over time. Can't send a message to a specific recipient, but I haven't needed that yet in my game so I don't mind it too much. What am I missing here? There must be a better implementation or some idea that I'm missing.

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  • Relationship between SOA and OOA

    - by TheSilverBullet
    Thomas Erl defines SOA as follows in his site: Service-oriented computing represents a new generation distributed computing platform. As such, it encompasses many things, including its own design paradigm and design principles, design pattern catalogs, pattern languages, a distinct architectural model, and related concepts, technologies, and frameworks. This definitely sounds like a whole new category which is parallel to object orientation. Almost one in which you would expect an entirely new language to exist for. Like procedural C and object oriented C#. Here is my understanding: In real life, we don't have entirely new language for SOA. And most application which have SOA architecture have an object oriented design underneath it. SOA is a "strategy" to make the entire application/service distributed and reliable. SOA needs OOPS working underneath it. Is this correct? Where does SOA (if at all it does) fit in with object oriented programming practices? Edit: I have learnt through answers that OOA and SOA work with each other and cannot be compared (in a "which is better" way). I have changed the title to "Relationship between SOA and OOA" rather than "comparison".

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  • How are objects modelled in a functional programming language?

    - by Giorgio
    In an answer to this question (written by Pete) there are some considerations about OOP versus FP. In particular, it is suggested that FP languages are not very suitable for modelling (persistent) objects that have an identity and a mutable state. I was wondering if this is true or, in other words, how one would model objects in a functional programming language. From my basic knowledge of Haskell I thought that one could use monads in some way, but I really do not know enough on this topic to come up with a clear answer. So, how are entities with an identity and a mutable persistent state normally modelled in a functional language? EDIT Here are some further details to clarify what I have in mind. Take a typical Java application in which I can (1) read a record from a database table into a Java object, (2) modify the object in different ways, (3) save the modified object to the database. How would this be implemented e.g. in Haskell? I would initially read the record into a record value (defined by a data definition), perform different transformations by applying functions to this initial value (each intermediate value is a new, modified copy of the original record) and then write the final record value to the database. Is this all there is to it? How can I ensure that at each moment in time only one copy of the record is valid / accessible? One does not want to have different immutable values representing different snapshots of the same object to be accessible at the same time.

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