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  • Multiple leaf methods problem in composite pattern

    - by Ondrej Slinták
    At work, we are developing an PHP application that would be later re-programmed into Java. With some basic knowledge of Java, we are trying to design everything to be easily re-written, without any headaches. Interesting problem came out when we tried to implement composite pattern with huge number of methods in leafs. What are we trying to achieve (not using interfaces, it's just an example): class Composite { ... } class LeafOne { public function Foo( ); public function Moo( ); } class LeafTwo { public function Bar( ); public function Baz( ); } $c = new Composite( Array( new LeafOne( ), new LeafTwo( ) ) ); // will call method Foo in all classes in composite that contain this method $c->Foo( ); It seems like pretty much classic Composite pattern, but problem is that we will have quite many leaf classes and each of them might have ~5 methods (of which few might be different than others). One of our solutions, which seems to be the best one so far and might actually work, is using __call magic method to call methods in leafs. Unfortunately, we don't know if there is an equivalent of it in Java. So the actual question is: Is there a better solution for this, using code that would be eventually easily re-coded into Java? Or do you recommend any other solution? Perhaps there's some different, better pattern I could use here. In case there's something unclear, just ask and I'll edit this post.

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  • Thread mutex behaviour

    - by Alberteddu
    Hi there, I'm learning C. I'm writing an application with multiple threads; I know that when a variable is shared between two or more threads, it is better to lock/unlock using a mutex to avoid deadlock and inconsistency of variables. This is very clear when I want to change or view one variable. int i = 0; /** Global */ static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER; /** Thread 1. */ pthread_mutex_lock(&mutex); i++; pthread_mutex_unlock(&mutex); /** Thread 2. */ pthread_mutex_lock(&mutex); i++; pthread_mutex_unlock(&mutex); This is correct, I think. The variable i, at the end of the executions, contains the integer 2. Anyway, there are some situations in which I don't know exactly where to put the two function calls. For example, suppose you have a function obtain(), which returns a global variable. I need to call that function from within the two threads. I have also two other threads that call the function set(), defined with a few arguments; this function will set the same global variable. The two functions are necessary when you need to do something before getting/setting the var. /** (0) */ /** Thread 1, or 2, or 3... */ if(obtain() == something) { if(obtain() == somethingElse) { // Do this, sometimes obtain() and sometimes set(random number) (1) } else { // Do that, just obtain(). (2) } } else { // Do this and do that (3) // If # of thread * 3 > 10, then set(3*10) For example. (4) } /** (5) */ Where I have to lock, and where I have to unlock? The situation can be, I think, even more complex. I will appreciate an exhaustive answer. Thank you in advance. —Alberto

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  • How to protect and hidden form HTML/PHP with JS callback to AS3

    - by Jk_
    Hi guys, I'm developing a Flash website (as3) where I need to be able to upload directly to YouTube by using the DATA API. However in order to do so, I had to use a proper HTML form on top of my flash object. Why? Because of the Browser Based Upload restictions. I first hide the form using JQuery and with a little CSS the form is display just where I want it. Within flash I use ExternalInterface.call() to show/hide the form when I need it! ExternalInterface.call("YTUploader.showIt"); The upload process is working great my only problem is that the form can be displayed easily... You just need a tool like firebug and you can use the form wherever you want on my flash app. So I was wandering which will be the best way to 'protect' this form or the best way to limit its access. Any advices will be appreciated. Thanks for your time. Jk.

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  • Visual Studio 2008 linker wants all symbols to be resolved, not only used ones

    - by user343011
    We recently upgraded to Visual Studio 2008 from 2005, and I think those error started after that. In our solution, we have a multitude of projects. Many of those are utility projects, or projects containing core functionality used by other projects. The output of those is lib files that are linked to when building the projects generating the final binaries using the "Project dependencies..." option. One of the other projects---Let us call it ResultLib---generates a DLL, and it needs one single function from the core project. This function uses only static function from its own source file, but the project in its entirety uses a lot of low-level Windows functions and also imports a DLL---Let us call it Driver.dll. Our problem is that when building ExtLib, the linker complains about a multitude of unresolved externals, for example all functions exported from Driver.dll, since its lib file is not specified when linking. If we try to fix this by adding all lib files used by other projects that use all of the core project, our resulting ResultLib DLL ends up importing Driver.dll and also exporting all functions defined in it. How do we tell Visual Studio to only try to resolve symbols that are actually used?

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  • PHP / Zend custom date input formats

    - by mld
    Hi, I'm creating a library component for other developers on my team using PHP and Zend. This component needs to be able to take as input a date (string) and another string telling it the format of that date. Looking through the Zend documentation and examples, I thought I found the solution - $dateObject = Zend_Date('13.04.2006', array('date_format' => 'dd.MM.yyyy')); this line, however, throws an error - call to undefined function. So instead I tried this - $dt = Zend_Locale_Format::getDate('13.04.2006', array('date_format' => 'dd.MM.yyyy')); This gets the job done, but throws an error if a date that is entered isn't valid. The docs make it look like you can use the isDate() function to check validity - Zend_Date::isDate('13.04.2006', array('date_format' => 'dd.MM.yyyy')) but this line always returns false. So my questions - Am I going about this the right way? If not, is there a better way to handle this via Zend or straight PHP? If I do use Zend_Locale_Format::getDate(), do I need to worry about a locale being set elsewhere and changing the results of the call? I'm locked into PHP 5.2.6 on windows, btw... so 5.3+ functions & strptime() are out.

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  • Run Reporting Service in local mode and generate columns automatically?

    - by grady
    Hi, I have a SQL query right now which I want to use with the MS reporting services in my ASP.NET application. So I created a report in local mode (rdlc) and attached this to a report viewer. Since my query uses parameters, I created a stored procedure, which had exactly those parameters. In addition to that I had some textboxes which are used for entering the params for the query and a button to call the stored proc and to fill the datatset which is bound to the report viewer. This works, I press the button and according to what I entred the correct data is shown. Now my question: In the future I plan to have multiple reports (which will be selected in a dropdown) and I wonder if I can somehow just call the correct stored procedure and according to the columns which are *SELECT*ed in the procedure, the columns are shown in the report. Example: I select report1 from the dropdown (procedure for report 1 is called), 5 columns are shown in the reportviewer. I select report2 from dropdown (procedure for report 2 is called), 8 columns are shown. Is that possible somehow? Thanks :-)

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  • iPhone SDK Programming - Working with a variable across 2 views

    - by SD
    I have what I hope is a fairly simple question about using the value from a variable across 2 views. I’m new to the iPhone SDK platform and the Model/View/Controller methodology. I’ve got background in VB.Net, some Php, but mostly SQL, so this is new ground for me. I’m building an app that has 3 views. For simplicity’s sake, I’ll call them View1, View2, View3. On View1 I have an NSString variable that I’ve declared in View1.h, and synthesized in View1.m. I’ll call it String1. View1.m uses a UITextField to ask the user for their name and then sets the value of String1 to that name (i.e. "Bill"). I would now like to use the value of String1 in View2. I'm not doing anything other than displaying the value ("Bill"), in a UILabel object in View2. Can someone tell me what the easiest way to accomplish that is? Many thanks in advance….

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  • Why does Perl's strict not let me pass a parameter hash?

    - by Thariama
    I hava a perl subroutine where i would like to pass parameters as a hash (the aim is to include a css depending on the parameter 'iconsize'). I am using the call: get_function_bar_begin('iconsize' => '32'); for the subroutine get_function_bar_begin: use strict; ... sub get_function_bar_begin { my $self = shift; my %template_params = %{ shift || {} }; return $self->render_template('global/bars /tmpl_incl_function_bar_begin.html',%template_params); } Why does this yield the error message: Error executing run mode 'start': undef error - Can't use string ("iconsize") as a HASH ref while "strict refs" in use at CheckBar.pm at line 334 Am i doing something wrong here? Is there an other way to submit my data ('iconsize') as a hash? (i am still new to Perl) EDIT: Solution which worked for me. I didn't change the call, but my function: sub get_function_bar_begin { my $self = shift; my $paramref = shift; my %params = (ref($paramref) eq 'HASH') ? %$paramref : (); my $iconsize = $params{'iconsize'} || ''; return $self->render_template('global/bars/tmpl_incl_function_bar_begin.html', { 'iconsize' => $iconsize, } ); }

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  • Is there a design pattern that expresses objects (an their operations) in various states?

    - by darren
    Hi I have a design question about the evolution of an object (and its state) after some sequence of methods complete. I'm having trouble articulating what I mean so I may need to clean up the question based on feedback. Consider an object called Classifier. It has the following methods: void initialise() void populateTrainingSet(TrainingSet t) void pupulateTestingSet(TestingSet t) void train() void test() Result predict(Instance i) My problem is that these methods need to be called in a certain order. Futher, some methods are invalid until a previous method is called, and some methods are invalid after a method has been called. For example, it would be invalid to call predict() before test() was called, and it would be invalid to call train() after test() was called. My approach so far has been to maintain a private enum that represents the current stateof the object: private static enum STATE{ NEW, TRAINED, TESTED, READY}; But this seems a bit cloogy. Is there a design pattern for such a problem type? Maybe something related to the template method.

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  • tcp/ip accept not returning, but client does

    - by paquetp
    server: vxworks 6.3 calls the usual socket, bind, listen, then: for (;;) { client = accept(sfd,NULL,NULL); // pass client to worker thread } client: .NET 2.0 TcpClient constructor to connect to server that takes the string hostname and int port, like: TcpClient client = new TcpClient(server_ip, port); This is working fine when the server is compiled and executed in windows (native c++). intermittently, the constructor to TcpClient will return the instance, without throwing any exception, but the accept call in vxWorks does not return with the client fd. tcpstatShow indicates no accept occurred. What could possibly make the TcpClient constructor (which calls 'Connect') return the instance, while the accept call on the server not return? It seems to be related to what the system is doing in the background - it seems more likely to get this symptom to occur when the server is busy persisting data to flash or an NFS share when the client attempts to connect, but can happen when it isn't also. I've tried adjusting priority of the thread running accept I've looked at the size of the queue in 'listen'. There's enough. The total number of file descriptors available should be enough (haven't validated this yet though, first thing in the morning)

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  • How to catch unintentional function interpositioning with GCC?

    - by SiegeX
    Reading through my book Expert C Programming, I came across the chapter on function interpositioning and how it can lead to some serious hard to find bugs if done unintentionally. The example given in the book is the following: my_source.c mktemp() { ... } main() { mktemp(); getwd(); } libc mktemp(){ ... } getwd(){ ...; mktemp(); ... } According to the book, what happens in main() is that mktemp() (a standard C library function) is interposed by the implementation in my_source.c. Although having main() call my implementation of mktemp() is intended behavior, having getwd() (another C library function) also call my implementation of mktemp() is not. Apparently, this example was a real life bug that existed in SunOS 4.0.3's version of lpr. The book goes on to explain the fix was to add the keyword static to the definition of mktemp() in my_source.c; although changing the name altogether should have fixed this problem as well. This chapter leaves me with some unresolved questions that I hope you guys could answer: Should our software group adopt the practice of putting the keyword static in front of all functions that we don't want to be exposed? Does GCC have a way to warn about function interposition? We certainly don't ever intend on this happening and I'd like to know about it if it does. Can interposition happen with functions introduced by static libraries? Thanks for the help.

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  • What wrapper class in C++ should I use for automated resource management?

    - by Vilx-
    I'm a C++ amateur. I'm writing some Win32 API code and there are handles and weirdly compositely allocated objects aplenty. So I was wondering - is there some wrapper class that would make resource management easier? For example, when I want to load some data I open a file with CreateFile() and get a HANDLE. When I'm done with it, I should call CloseHandle() on it. But for any reasonably complex loading function there will be dozens of possible exit points, not to mention exceptions. So it would be great if I could wrap the handle in some kind of wrapper class which would automatically call CloseHandle() once execution left the scope. Even better - it could do some reference counting so I can pass it around in and out of other functions, and it would release the resource only when the last reference left scope. The concept is simple - but is there something like that in the standard library? I'm using Visual Studio 2008, by the way, and I don't want to attach a 3rd party framework like Boost or something.

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  • jQuery.data() works in Mac OS WebKit, but not on iPhone OS?

    - by rpj
    I'm playing around with jQTouch for an iPhone OS app that I've been toying with off and on for a while. I wanted to try my hand building it as a web app so I started playing with jQTouch. For reference, here is the page+source (all my code is currently in index.html so you can just "View Source" to see it all): http://rpj.me/doughapp.com/wd/ Essentially, I'm trying to save pertinent JSON objects retrieved from Google Local into DOM objects using the data() method (in this example, obj is the Google Local object): $('#locPane').data('selected', obj); then later (in a different "pane"), retrieving that object to be used: $('#locPane').bind('pageAnimationEnd', function(e, inf) { var selobj = $(this).data('selected'); // use 'selobj' here ... } In Chromium and Safari on the desktop OS (Snow Leopard in my case), this works perfectly (try it out). However, the same code returns undefined for the call to $(this).data('selected') in the second snippet above. I've also tried $('#' + e.target.id).data('selected') and even the naive $('#locPane').data('selected'). All variants return undefined in the iPhone OS version of WebKit, but not on the desktop. Interestingly, the running this on Mobile Safari in the iPhone Simulator fails as well. If you look at the full source, you'll see that I even try to save this object into my global jQTouch object (named jqt in my code). This, too, fails on the mobile platform. Has anyone else ever ran into this? I'll admit to not being a web/javascript programmer by trade, so if I'm making an idiot's error please call me out on it. Thank you in advance for the help! -RPJ Update: I didn't make it clear in the original post, but I'm open to any workaround if it works consistently. Since I'm having trouble storing these objects in general, anything that allows me to keep them around is good enough for now. Thanks!

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  • Dynamic Select boxes page load

    - by Chris
    Hello, I have a dynamic chained select box that I am attempting to show the value of on a page load. In my chained select box, it will default to the first option within the select box on page load, could anyone provide assitance? I stumbled upon this thread, but I can't seem to translate what they are doing with that answer to my language of CF. Dynamic chained drop downs on page refresh Here is the JS script I am using. function dynamicSelect(id1, id2) { // Feature test to see if there is enough W3C DOM support if (document.getElementById && document.getElementsByTagName) { // Obtain references to both select boxes var sel1 = document.getElementById(id1); var sel2 = document.getElementById(id2); // Clone the dynamic select box var clone = sel2.cloneNode(true); // Obtain references to all cloned options var clonedOptions = clone.getElementsByTagName("option"); // Onload init: call a generic function to display the related options in the dynamic select box refreshDynamicSelectOptions(sel1, sel2, clonedOptions); // Onchange of the main select box: call a generic function to display the related options in the dynamic select box sel1.onchange = function() { refreshDynamicSelectOptions(sel1, sel2, clonedOptions); } } } function refreshDynamicSelectOptions(sel1, sel2, clonedOptions) { // Delete all options of the dynamic select box while (sel2.options.length) { sel2.remove(0); } // Create regular expression objects for "select" and the value of the selected option of the main select box as class names var pattern1 = /( |^)(select)( |$)/; var pattern2 = new RegExp("( |^)(" + sel1.options[sel1.selectedIndex].value + ")( |$)"); // Iterate through all cloned options for (var i = 0; i < clonedOptions.length; i++) { // If the classname of a cloned option either equals "select" or equals the value of the selected option of the main select box if (clonedOptions[i].className.match(pattern1) || clonedOptions[i].className.match(pattern2)) { // Clone the option from the hidden option pool and append it to the dynamic select box sel2.appendChild(clonedOptions[i].cloneNode(true)); } } } Thanks so much for any assistance

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  • Static member function pointer to hold non static member function

    - by user1425406
    This has defeated me. I want to have a static class variable which is a pointer to a (non-static) member function. I've tried all sorts of ways, but with no luck (including using typedefs, which just seemed to give me a different set of errors). In the code below I have the static class function pointer funcptr, and I can call it successfully from outside the class, but not from within the member function CallFuncptr - which is what I want to do. Any suggestions? #include <stdio.h> class A { public: static int (A::*funcptr)(); int Four() { return 4;}; int CallFuncptr() { return (this->*funcptr)(); } // doesn't link - undefined reference to `A::funcptr' }; int (A::*funcptr)() = &A::Four; int main() { A fred; printf("four? %d\n", (fred.*funcptr)()); // This works printf("four? %d\n", fred.CallFuncptr()); // But this is the way I want to call it }

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  • Java program using a class from a JAR file

    - by Myn
    Hi guys, I'll try to phrase this as best I can. I have a program which has an API-like functionality - it uses reflection to dynamically call methods from within a class. In this instance: Server.java public static void main(String[] args) { Class<?> clazz = Class.forName("DiHandler"); StHandler out = (StHandler) clazz; out.read(); DiHandler.java // implements StHandler import edu.ds.*; public void read() { Ds aType = new Ds(); aType = "134"; } So DiHandler has a method read() which can contain anything, it doesn't matter to Server.java after compile time. My problem is: DiHandler.java uses the class Ds from a JAR file. When I'm working on DiHandler.java in Eclipse (in a separate project from the project Server.java is in) I can add this JAR without a problem. But when I move DiHandler.class, after it's compiled, to be used by Server.class, how can it still use the JAR file? I hope this makes some sense, I suppose another way to phrase it would be how can I allow DiHandler to call on a class from the JAR without editing the classpath? Thanks very much in advance and sorry for any confusion or poor phrasing, I can only offer thanks and the customary offer of a pint for any assistance. M

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  • Centralizing Messagebox handling for application

    - by DRapp
    I'm wondering how others deal with trying to centralize MessageBox function calling. Instead of having long text embedded all over the place in code, in the past (non .net language), I would put system and application base "messagebox" type of messages into a database file which would be "burned" into the executable, much like a resource file in .Net. When a prompting condition would arise, I would just do call something like MBAnswer = MyApplication.CallMsgBox( IDUserCantDoThat ) then check the MBAnswer upon return, such as a yes/no/cancel or whatever. In the database table, I would have things like what the messagebox title would be, the buttons that would be shown, the actual message, a special flag that automatically tacked on a subsequent standard comment like "Please contact help desk if this happens.". The function would call the messagebox with all applicable settings and just return back the answer. The big benefits of this was, one location to have all the "context" of messages, and via constants, easier to read what message was going to be presented to the user. Does anyone have a similar system in .Net to do a similar approach, or is this just a bad idea in the .Net environment.

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  • what use does the javascript for each method have (that map can't do)?

    - by JohnMerlino
    Hey all, The only difference I see in map and foreach is that map is returning an array and foreach is not. However, I don't even understand the last line of the foreach method "func.call(scope, this[i], i, this);". For example, isn't "this" and "scope" referring to same object and isn't this[i] and i referring to the current value in the loop? I noticed on another post someone said "Use forEach when you want to do something on the basis of each element of the list. You might be adding things to the page, for example. Essentially, it's great for when you want "side effects". I don't know what is meant by side effects. Array.prototype.map = function(fnc) { var a = new Array(this.length); for (var i = 0; i < this.length; i++) { a[i] = fnc(this[i]); } return a; } Array.prototype.forEach = function(func, scope) { scope = scope || this; for (var i = 0, l = this.length; i < l; i++) func.call(scope, this[i], i, this); } Finally, are there any real uses for these methods in javascript (since we aren't updating a database) other than to manipulate numbers like this: alert([1,2,3,4].map(function(x){ return x + 1})); //this is the only example I ever see of map in javascript. Thanks for any reply.

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  • Advice on Minimizing Stored Procedure Parameters

    - by RPM1984
    Hi Guys, I have an ASP.NET MVC Web Application that interacts with a SQL Server 2008 database via Entity Framework 4.0. On a particular page, i call a stored procedure in order to pull back some results based on selections on the UI. Now, the UI has around 20 different input selections, ranging from a textbox, dropdown list, checkboxes, etc. Each of those inputs are "grouped" into logical sections. Example: Search box : "Foo" Checkbox A1: ticked, Checkbox A2: unticked Dropdown A: option 3 selected Checkbox B1: ticked, Checkbox B2: ticked, Checkbox B3: unticked So i need to call the SPROC like this: exec SearchPage_FindResults @SearchQuery = 'Foo', @IncludeA1 = 1, @IncludeA2 = 0, @DropDownSelection = 3, @IncludeB1 = 1, @IncludeB2 = 1, @IncludeB3 = 0 The UI is not too important to this question - just wanted to give some perspective. Essentially, i'm pulling back results for a search query, filtering these results based on a bunch of (optional) selections a user can filter on. Now, My questions/queries: What's the best way to pass these parameters to the stored procedure? Are there any tricks/new ways (e.g SQL Server 2008) to do this? Special "table" parameters/arrays - can we pass through User-Defined-Types? Keep in mind im using Entity Framework 4.0 - but could always use classic ADO.NET for this if required. What about XML? What are the serialization/de-serialization costs here? Is it worth it? How about a parameter for each logical section? Comma-seperated perhaps? Just thinking out loud. This page is particulary important from a user point of view, and needs to perform really well. The stored procedure is already heavy in logic, so i want to minimize the performance implications - so keep that in mind. With that said - what is the best approach here?

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  • problem linking vba modules in MS Access 2007

    - by Ted
    I am upgrading a database system from Access 2000 db to Access 2007, which communicates with several chemistry measuring devices(pH meter, scale, etc) via an RS 232 serial port. The first db consists of several modules containing vba code that enables the communications with the ports, as well as supports the code behind the forms in the second db. The user, or lab tech, navigates through the forms in the second db to interact with the lab devices, and also to generate the reports which display the info. from the devices. The reports are also part of the second db. The code works in Access 2000, but once I convert it to 2007, the code in the second db cannot find the function calls in the first db that dictate the progression from screen to screen. I have tried importing the modules into the second db, and I have tried linking them, but it still doesn't work. The error message is #438: "Object doesn't support this property or method." Any suggestions would be greatly appreciated. Here is the code for the first function that is not being called correctly: Description: ' This routine is used to return to the calling form and close the active form. ' ' Input: ' strFormCalled --- the active form ' strCallingForm --- the form that called the active form ' blnUnhideOrOpen --- whether to open or just unhide form Public Sub basReturnToCallingForm(ByVal strFormCalled As String, ByVal _ strCallingForm As Variant, Optional blnUnhideOrOpen As Boolean = True) On Error GoTo err_basReturnToCaliingForm If Not basIsBlankString(strCallingForm) And blnUnhideOrOpen Then DoCmd.OpenForm strCallingForm, acNormal Else Call basUnHideForm(strCallingForm) End If Call basCloseForm(strFormCalled) exit_basReturnToCaliingForm: Exit Sub err_basReturnToCaliingForm: Err.Raise Err.Number, "basReturnToCaliingForm", Err.Description End Sub I will post the second function shortly, but I have to go to a meeting... The second funtion that isn't 'working' is a cmdStartClick that is supposed to be called when a user initializes a pump. However, within that function, it's also sticking on a line that is supposed to progress to the next form in the db. The other thing is that the code works in Access 2002, but not in Access 2007...

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  • BufferedImage.getGraphics() resulting in memory leak, is there a fix?

    - by user359202
    Hi friends, I'm having problem with some framework API calling BufferedImage.getGraphics() method and thus causing memory leak. What this method does is that it always calls BufferedImage.createGraphics(). On a windows machine, createGraphics() is handled by Win32GraphicsEnvironment which keeps a listeners list inside its field displayChanger. When I call getGraphics on my BufferedImage someChart, someChart's SurfaceManager(which retains a reference to someChart) is added to the listeners map in Win32GraphicsEnvironment, preventing someChart to be garbage collected. Nothing afterwards removes someChart's SurfaceManager from the listeners map. In general, the summarized path stopping a BufferedImage from being garbage collected, once getGraphics is called, is as follows: GC Root - localGraphicsEnvironment(Win32GraphicsEnvironment) - displayChanger(SunDisplayChanger) - listeners(Map) - key(D3DChachingSurfaceManager) - bImg(BufferedImage) I could have changed the framework's code so that after every called to BufferedImage.getGraphics(), I keep a reference to the BufferedImage's SurfaceManager. Then, I get hold of localGraphicsEnvironment, cast it to Win32GraphicsEnvironment, then call removeDisplayChangedListener() using the reference to the BufferedImage's SurfaceManager. But I don't think this is a proper way to solve the problem. Could someone please help me with this issue? Thanks a lot!

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  • How to cancel a deeply nested process

    - by Mystere Man
    I have a class that is a "manager" sort of class. One of it's functions is to signal that the long running process of the class should shut down. It does this by setting a boolean called "IsStopping" in class. public class Foo { bool isStoping void DoWork() { while (!isStopping) { // do work... } } } Now, DoWork() was a gigantic function, and I decided to refactor it out and as part of the process broke some of it into other classes. The problem is, Some of these classes also have long running functions that need to check if isStopping is true. public class Foo { bool isStoping void DoWork() { while (!isStopping) { MoreWork mw = new MoreWork() mw.DoMoreWork() // possibly long running // do work... } } } What are my options here? I have considered passing isStopping by reference, which I don't really like because it requires there to be an outside object. I would prefer to make the additional classes as stand alone and dependancy free as possible. I have also considered making isStopping a property, and then then having it call an event that the inner classes could be subscribed to, but this seems overly complex. Another option was to create a "Process Cancelation Token" class, similar to what .net 4 Tasks use, then that token be passed to those classes. How have you handled this situation? EDIT: Also consider that MoreWork might have a EvenMoreWork object that it instantiates and calls a potentially long running method on... and so on. I guess what i'm looking for is a way to be able to signal an arbitrary number of objects down a call tree to tell them to stop what they're doing and clean up and return.

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  • My website keeps crashing IE, can't debug

    - by Ninja rhino
    I have a website that suddenly started to crash internet explorer. The website loads and starts executing javascript but somewhere in there the machinery explodes. I don't even get a script error, it just crashes. I've tried to manually step through every single line of js with the built in debugger but then of course the problem doesn't occur. If i choose to debug the application when it crashes i see the following message. Unhandled exception at 0x6c5dedf5 in iexplore.exe: 0xC0000005: Access violation reading location 0x00000090. The top 5 items in the call stack looks like this VGX.dll!6c5dedf5() [Frames below may be incorrect and/or missing, no symbols loaded for VGX.dll] VGX.dll!6c594d70() VGX.dll!6c594f63() VGX.dll!6c595350() VGX.dll!6c58f5e3() mshtml.dll!6f88dd17() VGX.dll seems to be part of the vml renderer and i am in fact using VML. I'm not suprised because i've had so many problems with vml, attributes has to be set in specific order, sometimes you cant set attributes when you have elements attached to the dom or vice versa (everything undocumented btw) but then the problems can usually be reproduced when debugging but not now :( The problem also occurs in no plugin-mode. Is there a better approach than trial and error to solve this? Edit: Adding a console outputting every suspect modification to the DOM made the problem only occur sometimes. (the console is also implemented in javascript on the same page, i'm able to see the output even after a crash as the window is still visible) Apparently it seems to be some kind of race condition. I managed to track it down even further, and it seems to occur when you remove an object from the DOM too quickly after it's just been added. (most likely only for vml-elements with some special attribute, didn't try further) And it can't be fixed by adding a dead loop in front of removeChild(pretty bad solution anyway), the page has to be rendered by the browser once after the addChild before you can call removeChild. sigh

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  • mysql_affected_rows() returns 0 for UPDATE statement even when an update actually happens

    - by Alex Moore
    I am trying to get the number of rows affected in a simple mysql update query. However, when I run this code below, PHP's mysql_affected_rows() always equals 0. No matter if foo=1 already (in which case the function should correctly return 0, since no rows were changed), or if foo currently equals some other integer (in which case the function should return 1). $updateQuery = "UPDATE myTable SET foo=1 WHERE bar=2"; mysql_query($updateQuery); if (mysql_affected_rows() > 0) { echo "affected!"; } else { echo "not affected"; // always prints not affected } The UPDATE statement itself works. The INT gets changed in my database. I have also double-checked that the database connection isn't being closed beforehand or anything funky. Keep in mind, mysql_affected_rows doesn't necessarily require you to pass a connection link identifier, though I've tried that too. Details on the function: mysql_affected_rows Any ideas? SOLUTION The part I didn't mention turned out to be the cause of my woes here. This PHP file was being called ten times consecutively in an AJAX call, though I was only looking at the value returned on the last call, ie. a big fat 0. My apologies!

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  • Remote interface lookup-problem in Glassfish3

    - by andersmo
    I have deployed a war-file, with actionclasses and a facade, and a jar-file with ejb-components (a stateless bean, a couple of entities and a persistence.xml) on glassfish3. My problem is that i cant find my remote interface to the stateless bean from my facade. My bean and interface looks like: @Remote public interface RecordService {... @Stateless(name="RecordServiceBean", mappedName="ejb/RecordServiceJNDI") public class RecordServiceImpl implements RecordService { @PersistenceContext(unitName="record_persistence_ctx") private EntityManager em;... and if i look in the server.log the portable jndi looks like: Portable JNDI names for EJB RecordServiceBean : [java:global/recordEjb/RecordServiceBean, java:global/recordEjb/RecordServiceBean!domain.service.RecordService]|#] and my facade: ...InitialContext ctx= new InitialContext(); try{ recordService = (RecordService) ctx.lookup("java:global/recordEjb/RecordServiceBean!domain.service.RecordService"); } catch(Throwable t){ System.out.println("ooops"); try{ recordService = (RecordService)ctx.lookup("java:global/recordEjb/RecordServiceImpl"); } catch(Throwable t2){ System.out.println("noooo!"); }... } and when the facade makes the first call this exception occur: javax.naming.NamingException: Lookup failed for 'java:global/recordEjb/RecordServiceBean!domain.service.RecordService' in SerialContext [Root exception is javax.naming.NamingException: ejb ref resolution error for remote business interfacedomain.service.RecordService [Root exception is java.lang.ClassNotFoundException: domain.service.RecordService]] and the second call: javax.naming.NamingException: Lookup failed for 'java:global/recordEjb/RecordServiceBean' in SerialContext [Root exception is javax.naming.NamingException: ejb ref resolution error for remote business interfacedomain.service.RecordService [Root exception is java.lang.ClassNotFoundException: domain.service.RecordService]] I have also tested to inject the bean with the @EJB-annotation: @EJB(name="RecordServiceBean") private RecordService recordService; But that doesnt work either. What have i missed? I tried with an ejb-jar.xml but that shouldnt be nessesary. Is there anyone who can tell me how to fix this problem?

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