Search Results

Search found 21702 results on 869 pages for 'large objects'.

Page 295/869 | < Previous Page | 291 292 293 294 295 296 297 298 299 300 301 302 | Next Page >

DDD and Client/Server apps

- by Christophe Herreman

I was wondering if any of you had successfully implemented DDD in a Client/Server app and would like to share some experiences. We are currently working on a smart client in Flex and a backend in Java. On the server we have a service layer exposed to the client that offers CRUD operations amongst some other service methods. I understand that in DDD these services should be repositories and services should be used to handle use cases that do not fit inside a repository. Right now, we mimic these services on the client behind an interface and inject implementations (Webservices, RMI, etc) via an IoC container. So some questions arise: should the server expose repositories to the client or do we need to have some sort of a facade (that is able to handle security for instance) should the client implement repositories (and DDD in general?) knowing that in the client, most of the logic is view related and real business logic lives on the server. All communication with the server happens asynchronously and we have a single threaded programming model on the client. how about mapping client to server objects and vice versa? We tried DTO's but reverted back to exposing the state of our objects and mapping directly to them. I know this is considered bad practice, but it saves us an incredible amount of time) In general I think a new generation of applications is coming with the growth of Flex, Silverlight, JavaFX and I'm curious how DDD fits into this.

Read the article
WPF DataGrid binding difficulties

- by Jasmin Pvvlovic

This is the class: public class TrainingData { public string Training { get; set; } } And this is the rest of the code in MainWindow: Excel.Workbook xlWorkbook = xlApp.Workbooks.Open("D:/excel.xlsx"); Excel._Worksheet xlWorksheet = xlWorkbook.Sheets[1]; Excel.Range xlRange = xlWorksheet.UsedRange; List <TrainingData> tData= new List <TrainingData>(); int rowCount = xlRange.Rows.Count; int colCount = xlRange.Columns.Count; //int k = 0; for (int i = 1; i <= rowCount; i++) { tData.Add(new TrainingData() { Training = xlRange.Cells[i, 1].Value2.ToString() }); //MessageBox.Show(tData[k].Training); //k++; } Prikaz.ItemsSource = tData; DataGrid: <DataGrid AutoGenerateColumns="False" Height="120" HorizontalAlignment="Left" Margin="12,12,0,0" Name="Prikaz" VerticalAlignment="Top" Width="105" ItemsSource="{Binding}"> <DataGrid.Columns> <DataGridTextColumn Header="Header" /> </DataGrid.Columns> </DataGrid>` So, Prikaz is my DataGrid. tData is List of TrainingData objects. If I uncomment these three lines I can test if I have imported information from excel file correctly, and yes, that works just fine. So why am I getting empty DataGrid? It has right number of rows and only one column, that's ok, but there are no data in it. I used this line: Prikaz.ItemsSource = tData; to bind my objects list and DataGrid. Training is declared public so it should be present in DataGrid. What could be causing the problem?

Read the article
Force full garbage collection when memory occupation goes beyond a certain threshold

- by Silvio Donnini

I have a server application that, in rare occasions, can allocate large chunks of memory. It's not a memory leak, as these chunks can be claimed back by the garbage collector by executing a full garbage collection. Normal garbage collection frees amounts of memory that are too small: it is not adequate in this context. The garbage collector executes these full GCs when it deems appropriate, namely when the memory footprint of the application nears the allotted maximum specified with -Xmx. That would be ok, if it wasn't for the fact that these problematic memory allocations come in bursts, and can cause OutOfMemoryErrors due to the fact that the jvm is not able to perform a GC quickly enough to free the required memory. If I manually call System.gc() beforehand, I can prevent this situation. Anyway, I'd prefer not having to monitor my jvm's memory allocation myself (or insert memory management into my application's logic); it would be nice if there was a way to run the virtual machine with a memory threshold, over which full GCs would be executed automatically, in order to release very early the memory I'm going to need. Long story short: I need a way (a command line option?) to configure the jvm in order to release early a good amount of memory (i.e. perform a full GC) when memory occupation reaches a certain threshold, I don't care if this slows my application down every once in a while. All I've found till now are ways to modify the size of the generations, but that's not what I need (at least not directly). I'd appreciate your suggestions, Silvio P.S. I'm working on a way to avoid large allocations, but it could require a long time and meanwhile my app needs a little stability

Read the article
Hooking thread exit

- by mackenir

Is there a way for me to hook the exit of managed threads (i.e. run some code on a thread, just before it exits?) I've developed a mechanism for hooking thread exit that works for some threads. Step 1: develop a 'hook' STA COM class that takes a callback function and calls it in its destructor. Step 2: create a ThreadStatic instance of this object on the thread I want to hook, and pass the object a managed delegate converted to an unmanaged function pointer. The delegate then gets called on thread exit (since the CLR calls IUnknown::Release on all STA COM RCWs as part of thread exit). This mechanism works on, for example, worker threads that I create in code using the Thread class. However, it doesn't seem to work for the application's main thread (be it a console or windows app). The 'hook' COM object seems to be deleted too late in the shutdown process and the attempt to call the delegate fails. (The reason I want to implement this facility is so I can run some native COM code on the exiting thread that works with STA COM objects that were created on the thread, before it's 'too late' (i.e. before the thread has exited, and it's no longer possible to work with STA COM objects on that thread.))

Read the article
Retrieve data from .dat file.

- by Zach

We have an application which requires us to read data from a file (.dat) dynamically using deserialization. We are actually getting first object and it throws null pointer exception when we are accessing other objects using a "for" loop. File file=null; FileOutputStream fos=null; BufferedOutputStream bos=null; ObjectOutputStream oos=null; try{ file=new File("account4.dat"); fos=new FileOutputStream(file,true); bos=new BufferedOutputStream(fos); oos=new ObjectOutputStream(bos); oos.writeObject(m); System.out.println("object serialized"); amlist=new MemberAccountList(); oos.close(); } catch(Exception ex){ ex.printStackTrace(); } Reading objects: try{ MemberAccount m1; file=new File("account4.dat");//add your code here fis=new FileInputStream(file); bis=new BufferedInputStream(fis); ois=new ObjectInputStream(bis); System.out.println(ois.readObject()); while(ois.readObject()!=null){ m1=(MemberAccount)ois.readObject(); System.out.println(m1.toString()); }/mList.addElement(m1); // Here we have the issue throwing null pointer exception Enumeration elist=mList.elements(); while(elist.hasMoreElements()){ obj=elist.nextElement(); System.out.println(obj.toString()); }/ } catch(ClassNotFoundException e){ } catch(EOFException e){ System.out.println("end"); } catch(Exception ex){ ex.printStackTrace(); }

Read the article
implementing twitter bootstrap carousel

- by arboles

I am having trouble implementing the bootstrap carousel. Can anyone look at the following html and js and give me instructions on how to implement the slide. The .js has not been edited and the carousel is installed on the body hero unit. Do I implement the carousel api? How do I define the carousel I am using within the .js file? Thanks. <div class="carousel">  <div class="carousel-inner">  <div class="hero-unit"> <h1>Hello, world!</h1> <p>This is a template for a simple marketing or informational website. It includes a large callout called the hero unit and three supporting pieces of content. Use it as a starting point to create something more unique.</p> <p><a class="btn btn-primary btn-large">Learn more »</a></p> </div> </div>  <a class="carousel-control left" href="#myCarousel" data-slide="prev">&lsaquo;</a> <a class="carousel-control right" href="#myCarousel" data-slide="next">&rsaquo;</a> </div>

Read the article
Positioning / Scrolling problem with Flex popup.

- by user284163

Hi all, I'm trying to work out a specific problem I'm having with positioning in Flex using the PopUpManager. Basically I'm wanting to create a popup which will scroll with the parent container - this is necessary because the parent container is large and if the user's browser window isn't large enough (this will be the case the majority of the time) - they will have to use the scrollbar of the container to scroll down. The problem is that the popup is positioned relative to another component, and it needs to stay by that component. <?xml version="1.0" encoding="utf-8"?> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute"> <mx:Script> <![CDATA[ import mx.core.UITextField; import mx.containers.TitleWindow; import mx.managers.PopUpManager; private function clickeroo(event:MouseEvent):void { var popup:TitleWindow = new TitleWindow(); popup.width = 250; popup.height = 300; popup.title = "Example"; var tf:UITextField = new UITextField(); tf.wordWrap = true; tf.width = popup.width - 30; tf.text = "This window stays put and doesn't scroll when the hbox is scrolled (even with using the hbox as parent in the addPopUp method), I need the popup to be local to the HBox."; popup.addChild(tf); PopUpManager.addPopUp(popup, hbox, false); PopUpManager.centerPopUp(popup); } ]]> </mx:Script> <mx:HBox width="100%" height="2000" id="hbox"> <mx:Button label="Click Me" click="clickeroo(event)"/> </mx:HBox> </mx:Application> Could anyone give me any pointers in the right direction? Thanks.

Read the article
Does GC guarantee that cleared References are enqueued to ReferenceQueue in topological order?

- by Dimitris Andreou

Say there are two objects, A and B, and there is a pointer A.x --> B, and we create, say, WeakReferences to both A and B, with an associated ReferenceQueue. Assume that both A and B become unreachable. Intuitively B cannot be considered unreachable before A is. In such a case, do we somehow get a guarantee that the respective references will be enqueued in the intuitive (topological when there are no cycles) order in the ReferenceQueue? I.e. ref(A) before ref(B). I don't know - what if the GC marked a bunch of objects as unreachable, and then enqueued them in no particular order? I was reviewing Finalizer.java of guava, seeing this snippet: private void cleanUp(Reference<?> reference) throws ShutDown { ... if (reference == frqReference) { /* * The client no longer has a reference to the * FinalizableReferenceQueue. We can stop. */ throw new ShutDown(); } frqReference is a PhantomReference to the used ReferenceQueue, so if this is GC'ed, no Finalizable{Weak, Soft, Phantom}References can be alive, since they reference the queue. So they have to be GC'ed before the queue itself can be GC'ed - but still, do we get the guarantee that these references will be enqueued to the ReferenceQueue at the order they get "garbage collected" (as if they get GC'ed one by one)? The code implies that there is some kind of guarantee, otherwise unprocessed references could theoretically remain in the queue. Thanks

Read the article
Removing a fields from a dynamic ModelForm

- by Jérôme Pigeot

In a ModelForm, i have to test user permissions to let them filling the right fields : It is defined like this: class TitleForm(ModelForm): def __init__(self, user, *args, **kwargs): super(TitleForm,self).__init__(*args, **kwargs) choices = [] # company if user.has_perm("myapp.perm_company"): self.fields['company'] = forms.ModelChoiceField(widget=forms.HiddenInput(), queryset=Company.objects.all(), required=False) choices.append('Company') # association if user.has_perm("myapp.perm_association") self.fields['association'] = forms.ModelChoiceField(widget=forms.HiddenInput(), queryset=Association.objects.all(), required=False) choices.append('Association') # choices self.fields['type_resource'] = forms.ChoiceField(choices = choices) class Meta: Model = Title This ModelForm does the work : i hide each field on the template and make them appearing thanks to javascript... The problem is this ModelForm is that each field defined in the model will be displayed on the template. I would like to remove them from the form if they are not needed: exemple : if the user has no right on the model Company, it won't be used it in the rendered form in the template. The problem of that is you have to put the list of fields in the Meta class of the form with fields or exclude attribute, but i don't know how to manage them dynamically. Any Idea?? Thanks by advance for any answer.

Read the article
Scaling Literate Programming?

- by Tetha

Greetings. I have been looking at Literate Programming a bit now, and I do like the idea behind it: you basically write a little paper about your code and write down as much of the design decisions, the code probably surrounding the module, the inner workins of the module, assumptions and conclusions resulting from the design decisions, potential extension, all this can be written down in a nice way using tex. Granted, the first point: it is documentation. It must be kept up-to-date, but that should not be that bad, because your change should have a justification and you can write that down. However, how does Literate Programming Scale to a larger degree? Overall, Literate Programming is still just text. Very human readable text, of course, but still text, and thus, it is hard to follow large systems. For example, I reworked large parts of my compiler to use and some magic to chain compile steps together, because some "x.register_follower(y); y.register_follower(z); y.register_follower(a);..." got really unwieldy, and changing that to x y z a made it a bit better, even though this is at its breaking point, too. So, how does Literate Programming scale to larger systems? Does anyone try to do that? My thought would be to use LP to specify components that communicate with each other using event streams and chain all of these together using a subset of graphviz. This would be a fairly natural extension to LP, as you can extract a documentation -- a dataflow diagram -- from the net and also generate code from it really well. What do you think of it? -- Tetha.

Read the article
XCTest.framework build error

- by user2703123

I am using the DropBox Core API in my app and therefore, I must include the XCTest framework, because, when I haven't added the XCTest framework, my app can't connect to dropbox, however when I do add the framework, I get an error while building for the simulator. There is nothing wrong with my code! Here is the error: Ld /Users/Zach/Library/Developer/Xcode/DerivedData/SnapDrop!-fchnxyvnqyeefscfhmohrzxtiqeb/Build/Products/Debug-iphonesimulator/SnapDrop!.app/SnapDrop! normal i386 cd "/Users/Zach/Desktop/SnapDrop!" setenv IPHONEOS_DEPLOYMENT_TARGET 6.1 setenv PATH "/Applications/Xcode5-DP6.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode5-DP6.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin" /Applications/Xcode5-DP6.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang -arch i386 -isysroot /Applications/Xcode5-DP6.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator7.0.sdk -L/Users/Zach/Library/Developer/Xcode/DerivedData/SnapDrop!-fchnxyvnqyeefscfhmohrzxtiqeb/Build/Products/Debug-iphonesimulator -F/Users/Zach/Library/Developer/Xcode/DerivedData/SnapDrop!-fchnxyvnqyeefscfhmohrzxtiqeb/Build/Products/Debug-iphonesimulator -F/Users/Zach/Downloads/dropbox-ios-sdk-1.3.5 -F/Users/Zach/Downloads/dropbox-ios-sync-sdk-1-1.1.0 -F/Applications/Xcode5-DP6.app/Contents/Developer/Library/Frameworks -F/Users/Zach/Desktop -filelist /Users/Zach/Library/Developer/Xcode/DerivedData/SnapDrop!-fchnxyvnqyeefscfhmohrzxtiqeb/Build/Intermediates/SnapDrop!.build/Debug-iphonesimulator/SnapDrop!.build/Objects-normal/i386/SnapDrop!.LinkFileList -Xlinker -objc_abi_version -Xlinker 2 -fobjc-arc -fobjc-link-runtime -Xlinker -no_implicit_dylibs -mios-simulator-version-min=6.1 -framework iAd -framework AssetsLibrary -framework QuartzCore -framework SystemConfiguration -framework Security -framework CFNetwork -framework XCTest -framework Dropbox -framework DropboxSDK -framework CoreGraphics -framework UIKit -framework Foundation -Xlinker -dependency_info -Xlinker /Users/Zach/Library/Developer/Xcode/DerivedData/SnapDrop!-fchnxyvnqyeefscfhmohrzxtiqeb/Build/Intermediates/SnapDrop!.build/Debug-iphonesimulator/SnapDrop!.build/Objects-normal/i386/SnapDrop!_dependency_info.dat -o /Users/Zach/Library/Developer/Xcode/DerivedData/SnapDrop!-fchnxyvnqyeefscfhmohrzxtiqeb/Build/Products/Debug-iphonesimulator/SnapDrop!.app/SnapDrop! ld: building for iOS Simulator, but linking against dylib built for MacOSX file '/Applications/Xcode5-DP6.app/Contents/Developer/Library/Frameworks/XCTest.framework/XCTest' for architecture i386 clang: error: linker command failed with exit code 1 (use -v to see invocation) What should I do? If my framework is corrupt, can you tell me how to reinstall it? I have tried deleting and reinstalling Xcode with no luck.

Read the article
(C#) Get index of current foreach iteration

- by Graphain

Hi, Is there some rare language construct I haven't encountered (like the few I've learned recently, some on Stack Overflow) in C# to get a value representing the current iteration of a foreach loop? For instance, I currently do something like this depending on the circumstances: int i=0; foreach (Object o in collection) { ... i++; } Answers: @bryansh: I am setting the class of an element in a view page based on the position in the list. I guess I could add a method that gets the CSSClass for the Objects I am iterating through but that almost feels like a violation of the interface of that class. @Brad Wilson: I really like that - I've often thought about something like that when using the ternary operator but never really given it enough thought. As a bit of food for thought it would be nice if you could do something similar to somehow add (generically to all IEnumerable objects) a handle on the enumerator to increment the value that an extension method returns i.e. inject a method into the IEnumerable interface that returns an iterationindex. Of course this would be blatant hacks and witchcraft... Cool though... @crucible: Awesome I totally forgot to check the LINQ methods. Hmm appears to be a terrible library implementation though. I don't see why people are downvoting you though. You'd expect the method to either use some sort of HashTable of indices or even another SQL call, not an O(N) iteration... (@Jonathan Holland yes you are right, expecting SQL was wrong) @Joseph Daigle: The difficulty is that I assume the foreach casting/retrieval is optimised more than my own code would be. @Jonathan Holland: Ah, cheers for explaining how it works and ha at firing someone for using it.

Read the article
How do you create a non-Thread-based Guice custom Scope?

- by Russ

It seems that all Guice's out-of-the-box Scope implementations are inherently Thread-based (or ignore Threads entirely): Scopes.SINGLETON and Scopes.NO_SCOPE ignore Threads and are the edge cases: global scope and no scope. ServletScopes.REQUEST and ServletScopes.SESSION ultimately depend on retrieving scoped objects from a ThreadLocal<Context>. The retrieved Context holds a reference to the HttpServletRequest that holds a reference to the scoped objects stored as named attributes (where name is derived from com.google.inject.Key). Class SimpleScope from the custom scope Guice wiki also provides a per-Thread implementation using a ThreadLocal<Map<Key<?>, Object>> member variable. With that preamble, my question is this: how does one go about creating a non-Thread-based Scope? It seems that something that I can use to look up a Map<Key<?>, Object> is missing, as the only things passed in to Scope.scope() are a Key<T> and a Provider<T>. Thanks in advance for your time.

Read the article
XNA 2D mouse picking

- by Corndog

I'm working on a simple 2D Real time strategy game using XNA. Right now I have reached the point where I need to be able to click on the sprite for a unit or building and be able to reference the object associated with that sprite. From the research I have done over the last three days I have found many references on how to do "Mouse picking" in 3D which does not seem to apply to my situation. I understand that another way to do this is to simply have an array of all "selectable" objects in the world and when the player clicks on a sprite it checks the mouse location against the locations of all the objects in the array. the problem I have with this approach is that it would become rather slow if the number of units and buildings grows to larger numbers. (it also does not seem very elegant) so what are some other ways I could do this. (Please note that I have also worked over the ideas of using a Hash table to associate the object with the sprite location, and using a 2 dimensional array where each location in the array represents one pixel in the world. once again they seem like rather clunky ways of doing things.)

Read the article
Data in two databases, eager spool resulting in query

- by Valkyrie

I have two databases in SQL2k5: one that holds a large amount of static data (SQL Database 1) (never updated but frequently inserted into) and one that holds relational data (SQL Database 2) related to the static data. They're separated mainly because of corporate guidelines and business requirements: assume for the following problem that combining them is not practical. There are places in SQLDB2 that PKs in SQLDB1 are referenced; triggers control the referential integrity, since cross-database relationships are troublesome in SQL Server. BUT, because of the large amount of data in SQLDB1, I'm getting eager spools on queries that join from the Id in SQLDB2 that references the data in SQLDB1. (With me so far? Maybe an example will help:) SELECT t.Id, t.Name, t2.Company FROM SQLDB1.table t INNER JOIN SQLDB2.table t2 ON t.Id = t2.FKId This query results in a eager spool that's 84% of the load of the query; the table in SQLDB1 has 35M rows, so it's completely choking this query. I can't create a view on the table in SQLDB1 and use that as my FK/index; it doesn't want me to create a constraint based on a view. Anyone have any idea how I can fix this huge bottleneck? (Short of putting the static data in the first db: believe me, I've argued that one until I'm blue in the face to no avail.) Thanks! valkyrie Edit: also can't create an indexed view because you can't put schemabinding on a view that references a table outside the database where the view resides. Dang it.

Read the article
Delete NSManageObject at the event tableView:commitEditingStyle:forRowAtIndexPath:

- by David.Chu.ca

I got exception when I tried to delete one NSManageObject at the event of tableView:commitEditingStyle:forRowAtIndexPath:. Here is the part of my codes: - (void)tableView:(..)tableView commitEditingStyle:(..)editingStyle forRowAtIndexPath:(..)indexPath { if (editingStyle == UITableViewCellEditingStyleDelete) { [managedObjectContext deleteObject: [fetchedResultController objectAtIndexPath:indexPath]]; ... } } The exception was thrown at the line of deleteObject:(method of my local NSManagedObjectContext). This is the exception message: uncaught exception 'NSObjectInaccessibleException', reason: 'The NSManagedObject with ID:0x3d07a30 <x-coredata://0D2CC9CB-042B-496D-B3FE-5F1ED64EAB97/paymentType/p2> has been invalidated.' I tried to get entity object first and then to delete it. The entity looks OK but still the exception was at delete: NSManagedObject *entityToDelete = [fetchedResultsController objectAtIndexPath:indexPath]; [mangedObjectContext deleteObject:entityToDelete]; // Exception again. I am not sure if the entity object retrieved from the fetchedResultsController(NSFetchedResultsController type) cannot be deleted? If so, is there any other way to get the entity object for deleting? I found that in the Apple's Core Data Tutorial for iPhone with events example, there is on NSArray to hold event entity objects. I am not sure if that's necessory to use NSArray to hold my local entity objects and then use it for deleting?

Read the article
Should the entity framework + self tracking entities be saving me time

- by sipwiz

I've been using the entity framework in combination with the self tracking entity code generation templates for my latest silverlight to WCF application. It's the first time I've used the entity framework in a real project and my hope was that I would save myself a lot of time and effort by being able to automatically update the whole data access layer of my project when my database schema changed. Happily I've found that to be the case, updating my database schema by adding a new table, changing column names, adding new columns etc. etc. can be propagated to my business object classes by using the update from database option on the entity framework model. Where I'm hurting is the CRUD operations within my WCF service in response to actions on my Silverlight client. I use the same self tracking entity framework business objects in my Silverlight app but I find I'm continually having to fight against problems such as foreign key associations not being handled correctly when updating an object or the change tracker getting confused about the state of an object at the Silverlight end and the data access operation within the WCF layer throwing a wobbly. It's got to a point where I have now spent more time dealing with this quirks than I have on my previous project where I used Linq-to-SQL as the starting point for rolling my own business objects. Is it just me being hopeless or is the self tracking entities approach something that should be avoided until it's more mature?

Read the article
TDD test data loading methods

- by Dave Hanson

I am a TDD newb and I would like to figure out how to test the following code. I am trying to write my tests first, but I am having trouble for creating a test that touches my DataAccessor. I can't figure out how to fake it. I've done the extend the shipment class and override the Load() method; to continue testing the object. I feel as though I end up unit testing my Mock objects/stubs and not my real objects. I thought in TDD the unit tests were supposed to hit ALL of the methods on the object; however I can never seem to test that Load() code only the overriden Mock Load My tests were write an object that contains a list of orders based off of shipment number. I have an object that loads itself from the database. public class Shipment { //member variables protected List<string> _listOfOrders = new List<string>(); protected string _id = "" //public properties public List<string> ListOrders { get{ return _listOfOrders; } } public Shipment(string id) { _id = id; Load(); } //PROBLEM METHOD // whenever I write code that needs this Shipment object, this method tries // to hit the DB and fubars my tests // the only way to get around is to have all my tests run on a fake Shipment object. protected void Load() { _listOfOrders = DataAccessor.GetOrders(_id); } } I create my fake shipment class to test the rest of the classes methods .I can't ever test the Real load method without having an actual DB connection public class FakeShipment : Shipment { protected new void Load() { _listOfOrders = new List<string>(); } } Any thoughts? Please advise. Dave

Read the article
Oracle T4CPreparedStatement memory leaks?

- by Jay

A little background on the application that I am gonna talk about in the next few lines: XYZ is a data masking workbench eclipse RCP application: You give it a source table column, and a target table column, it would apply a trasformation (encryption/shuffling/etc) and copy the row data from source table to target table. Now, when I mask n tables at a time, n threads are launched by this app. Here is the issue: I have run into a production issue on first roll out of the above said app. Unfortunately, I don't have any logs to get to the root. However, I tried to run this app in test region and do a stress test. When I collected .hprof files and ran 'em through an analyzer (yourKit), I noticed that objects of oracle.jdbc.driver.T4CPreparedStatement was retaining heap. The analysis also tells me that one of my classes is holding a reference to this preparedstatement object and thereby, n threads have n such objects. T4CPreparedStatement seemed to have character arrays: lastBoundChars and bindChars each of size char[300000]. So, I researched a bit (google!), obtained ojdbc6.jar and tried decompiling T4CPreparedStatement. I see that T4CPreparedStatement extends OraclePreparedStatement, which dynamically manages array size of lastBoundChars and bindChars. So, my questions here are: Have you ever run into an issue like this? Do you know the significance of lastBoundChars / bindChars? I am new to profiling, so do you think I am not doing it correct? (I also ran the hprofs through MAT - and this was the main identified issue - so, I don't really think I could be wrong?) I have found something similar on the web here: http://forums.oracle.com/forums/thread.jspa?messageID=2860681 Appreciate your suggestions / advice.

Read the article
Frameworks to manage dates (effective date and expiry dates)

- by user214626

Hello, We have an object that can has an effective date and expiry date.(Ex. i want to maintain the price of a commodity for a time period) Business Rules - Effective date is always a valid date (a datestamp) but, expiry date can be null to indicate that the object is active throughout. Also, both effective and expiry date can be set to some valid dates. Are there any frameworks that manage objects such that the objects are consistent,i.e there are no overlaps of the validity periods ? Ex. class XBOX { double price; Date effectiveDate; Date expiryDate; } XBOX x1 = new XBOX(400$, '2007-01-01','2008-12-31' ); XBOX x2 = new XBOX(200$, '2009-01-01',null ); Assume that we get a new rate from '2010-01-01' and a new XBOX object has to be created (to persist). Is there a framework/pattern that can do the following, so that the XBOX is consistent. x2.setExpiryDate('2009-12-31') XBOX x3 = new XBOX(150$, '2010-01-01',null ); Thanks in advance.

Read the article
In ParallelPython, a method of an object ( object.func() ) fails to manipulate a variable of an object ( object.value )

- by mehmet.ali.anil

With parallelpython, I am trying to convert my old serial code to parallel, which heavily relies on objects that have methods that change that object's variables. A stripped example in which I omit the syntax in favor of simplicity: class Network: self.adjacency_matrix = [ ... ] self.state = [ ... ] self.equilibria = [ ... ] ... def populate_equilibria(self): # this function takes every possible value that self.state can be in # runs the boolean dynamical system # and writes an integer within self.equilibria for each self.state # doesn't return anything I call this method as: Code: j1 = jobserver.submit(net2.populate_equilibria,(),(),("numpy as num")) The job is sumbitted, and I know that a long computation takes place, so I speculate that my code is ran. The problem is, i am new to parallelpython , I was expecting that, when the method is called, the variable net2.equilibria would be written accordingly, and I would get a revised object (net2) . That is how my code works, independent objects with methods that act upon the object's variables. Rather, though the computation is apparent, and reasonably timed, the variable net2.equilibria remains unchanged. As if PP only takes the function and the object, computes it elsewhere, but never returns the object, so I am left with the old one. What do I miss? Thanks in advance.

Read the article
How can I stop an auto-generated Linq to SQL class from loading ALL data?

- by Gary McGill

I have an ASP.NET MVC project, much like the NerdDinner tutorial example. (I'm using MVC 2, but followed the NerdDinner tutorial in order to create it). As per the instructions in part 3 of the tutorial, I've created a Linq-to-SQL model of my database by creating a "Linq to SQL Classes" (.dbml) surface, and dropping my database tables onto it. The designer has automatically added relationships between the generated classes based on my database tables. Let's say that my classes are as per the NerdDinner example, so I have Dinner and RSVP tables, where each Dinner record is associated with many RSVP records - hence in the generated classes, the Dinner object has a RSVPs property which is a list of RSVP objects. My problem is this: it appears (and I'd be gladly proved wrong on this) that as soon as I access a Dinner object, it's loading all of the corresponding RSVP objects, even if I don't use the RSVPs member. First question: is this really the default behavior for the generated classes? In my particular situation, the object graph contains many more tables (which have an order of magnitude more records), and so this is disastrous behaviour - I'd be loading tons of data when all I want to do is show the details of a single parent record. Second question: are there any properties exposed through the designer UI that would let me modify this behavior? (I can't find any). Third question: I've seen a description of how to control the loading of related records in a DataContext by using a DataShape object associated with the DataContext. Is that what I'm meant to do, and if so are there any tutorials like the NerdDinner one that would show not only how to do it, but also suggest a 'pattern' for normal use?

Read the article
How can I stop an auto-generated Linq to SQL class from loading ALL data?

- by Gary McGill

DUPLICATE of http://stackoverflow.com/questions/2433422/how-can-i-stop-an-auto-generated-linq-to-sql-class-from-loading-all-data post answers there! I have an ASP.NET MVC project, much like the NerdDinner tutorial example. (I'm using MVC 2, but followed the NerdDinner tutorial in order to create it). As per the instructions in part 3 of the tutorial, I've created a Linq-to-SQL model of my database by creating a "Linq to SQL Classes" (.dbml) surface, and dropping my database tables onto it. The designer has automatically added relationships between the generated classes based on my database tables. Let's say that my classes are as per the NerdDinner example, so I have Dinner and RSVP tables, where each Dinner record is associated with many RSVP records - hence in the generated classes, the Dinner object has a RSVPs property which is a list of RSVP objects. My problem is this: it appears (and I'd be gladly proved wrong on this) that as soon as I access a Dinner object, it's loading all of the corresponding RSVP objects, even if I don't use the RSVPs member. First question: is this really the default behavior for the generated classes? In my particular situation, the object graph contains many more tables (which have an order of magnitude more records), and so this is disastrous behaviour - I'd be loading tons of data when all I want to do is show the details of a single parent record. Second question: are there any properties exposed through the designer UI that would let me modify this behavior? (I can't find any). Third question: I've seen a description of how to control the loading of related records in a DataContext by using a DataShape object associated with the DataContext. Is that what I'm meant to do, and if so are there any tutorials like the NerdDinner one that would show not only how to do it, but also suggest a 'pattern' for normal use?

Read the article
How to build n-layered web architecture with PHP?

- by Alex

I have a description and design of a website and I need to redesign it to allow for new requirements. The website's purpose is the offering of government's contracts and bidding opportunities for different businesses.I'm dealing with the 3-tier architecture PHP website comprising of the user-interface tier(client's web browser),business logic layer(Apache web server with PHP engine in it and a couple of applications running within a web server as well) and a database layer(local mysql database). Now,i need to redesign it to su???rt distributed n-tier architecture and specify how I would go about it.After long hours of research i came to this solution: business logic should be separated into presentation and purely business logic tier to allow for n-layer architecture(user-interface,presentation tier,b.logic and data tier).I have decided to use ??? just for the presentation(since the original existing website is in PHP) and use it within apache web server.In the business logic i want to use J2?? implementation technology instead of implementing it in PHP(i.e using Zend app.server and smarty template) cz J2EE can provide much more essential container services which are essential for business logic,its robustness,maintainability and different critical business operations which will be carried out by the g?v?rnment's website.So,particularly,i want to use J??ss app.server with ?J? business objects in it which would provide all the b.logic in java and would interact with the database and so forth.In order to connect PHP on a web server with java on app.server i'm gonna use PHP/Java bridge API (or maybe Quercus or SOAP is better?).Finally,i have my data tier with mysql which will communicate with b.logic via JD??.Payment system application in ???.server is gonna use S??? to talk with credit card company. From your professional point of view,does it sound like a good way of redesigning the original website to allow for n-tier architecture considering the specifics of the website and the criticality of its operations?(payment system is included in it)or u would personally prefer to use PHP business objects for business logic as well instead of J2EE?If you have any wiser recommendation or some alternative,please let me know what is right or wrong in my current solution. H??? to hear your professional advice very s??n (I'm new to the area of web development) Thanks in advance

Read the article
Bloated PDF created by TCPDF

- by Yogi Yang 007

In a web app developed in PHP we are generating Quotations and Invoices (which are very simple and of single page) using TCPDF lib. The lib is working just great but it seems to generate very large PDF files. For example in our case it is generating PDF files as large as 4 MB (+/- a few KB). How to reduce this bloating of PDF files generated by TCPDF? Here is code snippet that I am using ob_start(); include('quote_view_bag_pdf.php'); //This file is valid HTML file with PHP code to insert data from DB $quote = ob_get_contents(); //Capture the content of 'quote_view_bag_pdf.php' file and store in variable ob_end_clean(); //Code to generate PDF file for this Quote //This line is to fix a few errors in tcpdf $k_path_url=''; require_once('tcpdf/config/lang/eng.php'); require_once('tcpdf/tcpdf.php'); // create new PDF document $pdf = new TCPDF(); // remove default header/footer $pdf->setPrintHeader(false); $pdf->setPrintFooter(false); // add a page $pdf->AddPage(); // print html formated text $pdf->writeHtml($quote, true, 0, true, 0); //Insert Variables contents here. //Build Out File Name $pdf_out_file = "pdf/Quote_".$_POST['quote_id']."_.pdf"; //Close and output PDF document $pdf->Output($pdf_out_file, 'F'); $pdf->Output($pdf_out_file, 'I'); /////////////// enter code here Hope this code fragment will give some idea?

Read the article

< Previous Page | 291 292 293 294 295 296 297 298 299 300 301 302 | Next Page >