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• Choosing a distributed shared memory solution

  - by mindas

  I have a task to build a prototype for a massively scalable distributed shared memory (DSM) app. The prototype would only serve as a proof-of-concept, but I want to spend my time most effectively by picking the components which would be used in the real solution later on. The aim of this solution is to take data input from an external source, churn it and make the result available for a number of frontends. Those "frontends" would just take the data from the cache and serve it without extra processing. The amount of frontend hits on this data can literally be millions per second. The data itself is very volatile; it can (and does) change quite rapidly. However the frontends should see "old" data until the newest has been processed and cached. The processing and writing is done by a single (redundant) node while other nodes only read the data. In other words: no read-through behaviour. I was looking into solutions like memcached however this particular one doesn't fulfil all our requirements which are listed below: The solution must at least have Java client API which is reasonably well maintained as the rest of app is written in Java and we are seasoned Java developers; The solution must be totally elastic: it should be possible to add new nodes without restarting other nodes in the cluster; The solution must be able to handle failover. Yes, I realize this means some overhead, but the overall served data size isn't big (1G max) so this shouldn't be a problem. By "failover" I mean seamless execution without hardcoding/changing server IP address(es) like in memcached clients when a node goes down; Ideally it should be possible to specify the degree of data overlapping (e.g. how many copies of the same data should be stored in the DSM cluster); There is no need to permanently store all the data but there might be a need of post-processing of some of the data (e.g. serialization to the DB). Price. Obviously we prefer free/open source but we're happy to pay a reasonable amount if a solution is worth it. In any way, paid 24hr/day support contract is a must. The whole thing has to be hosted in our data centers so SaaS offerings like Amazon SimpleDB are out of scope. We would only consider this if no other options would be available. Ideally the solution would be strictly consistent (as in CAP); however, eventual consistence can be considered as an option. Thanks in advance for any ideas.

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• Validating against a Schema with JAXB

  - by fwgx

  I've been looking for solutions to this problem for far too long considering how easy it sounds so I've come for some help. I have an XML Schema which I have used with xjc to create my JAXB binding. This works fine when the XML is well formed. Unfortunately it also doesn't complain when the XML is not well formed. I cannot figure out how to do proper full validation against the schema when I try to unmarshall an XML file. I have managed to use a ValidationEventCollector to handle events, which works for XML parsing errors such as mismatched tags but doesn't raise any events when there is a tag that is required but is completely absent. From what I have seen validation can be done againsta schema, but you must know the path to the schema in order to pass it into the setSchema() method. The problem I have is that the path to the schema is stored in the XML header and I can't knwo at run time where the schema is going to be. Which is why it's stored in the XML file: <?xml version="1.0" encoding="utf-8"?> <DDSSettings xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="/a/big/long/path/to/a/schema/file/DDSSettings.xsd"> <Field1>1</Field1> <Field2>-1</Field2> ...etc Every example I see uses setValidating(true), which is now deprecated, so throws an exception. This is the Java code I have so far, which seems to only do XML validation, not schema validation: try { JAXBContext jc = new JAXBContext() { private final JAXBContext jaxbContext = JAXBContext.newInstance("blah"); @Override public Unmarshaller createUnmarshaller() throws JAXBException { Unmarshaller unmarshaller = jaxbContext.createUnmarshaller(); ValidationEventCollector vec = new ValidationEventCollector() { @Override public boolean handleEvent(ValidationEvent event) throws RuntimeException { ValidationEventLocator vel = event.getLocator(); if (event.getSeverity() == event.ERROR || event.getSeverity() == event.FATAL_ERROR) { String error = "XML Validation Exception: " + event.getMessage() + " at row: " + vel.getLineNumber() + " column: " + vel.getColumnNumber(); System.out.println(error); } m_unmarshallingOk = false; return false; } }; unmarshaller.setEventHandler(vec); return unmarshaller; } @Override public Marshaller createMarshaller() throws JAXBException { throw new UnsupportedOperationException("Not supported yet."); } @Override @SuppressWarnings("deprecation") public Validator createValidator() throws JAXBException { throw new UnsupportedOperationException("Not supported yet."); } }; Unmarshaller unmarshaller = jc.createUnmarshaller(); m_ddsSettings = (com.ultra.DDSSettings)unmarshaller.unmarshal(new File(xmlfileName)); } catch (UnmarshalException ex) { Logger.getLogger(UniversalDomainParticipant.class.getName()).log( Level.SEVERE, null, ex); } catch (JAXBException ex) { Logger.getLogger(UniversalDomainParticipant.class.getName()).log( Level.SEVERE, null, ex); } So what is the proper way to do this validation? I was expecting there to be a validate() method on the JAXB generated classes, but I guess that would be too simple for Java.

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• Feeding PDF through IInternetSession to WebBrowser control - Error

  - by Codesleuth

  As related to my previous question, I have developed a temporary asynchronous pluggable protocol with the specific aim to be able to serve PDF documents directly to a WebBrowser control via a database. I need to do this because my limitations include not being able to access the disk other than IsolatedStorage; and a MemoryStream would be far better for serving up PDF documents that average around 31kb. Unfortunately the code doesn't work, and I'm getting an error from the WebBrowser control (i.e. IE): Unable to download . Unable to open this Internet site. The requested site is either unavailable or cannot be found. Please try again later. The line in my code where this occurs is within the following: pOIProtSink.ReportData(BSCF.BSCF_LASTDATANOTIFICATION, (uint)_stream.Length, (uint)_stream.Length); However, if you download the project and run it, you will be able to see the stream is successfully read and passed to the browser, so it seems like there's a problem somewhere to do with the end of reading the data: public uint Read(IntPtr pv, uint cb, out uint pcbRead) { var bytesToRead = Math.Min(cb, _streamBuffer.Length); pcbRead = (uint)_stream.Read(_streamBuffer, 0, (int)bytesToRead); Marshal.Copy(_streamBuffer, 0, pv, (int)pcbRead); return (pcbRead == 0 || pcbRead < cb) ? HRESULT.S_FALSE : HRESULT.S_OK; } Here is the entire sample project: InternetSessionSample.zip (VS2010) I will leave this up for as long as I can to help other people in the future If anyone has any ideas why I might be getting this message and can shed some light on the problem, I would be grateful for the assistance. EDIT: A friend suggested inserting a line that calls the IInternetProtocolSink.ReportProgress with BINDSTATUS_CACHEFILENAMEAVAILABLE pointing at the original file. This prevents it from failing now and shows the PDF in the Adobe Reader control, but means it defeats the purpose of this by having Adobe Reader simply load from the cache file (which I can't provide). See below: pOIProtSink.ReportProgress(BINDSTATUS.BINDSTATUS_CACHEFILENAMEAVAILABLE, @"D:\Visual Studio Solutions\Projects\InternetSessionSample\bin\Debug\sample.pdf"); pOIProtSink.ReportData(BSCF.BSCF_LASTDATANOTIFICATION, (uint)_stream.Length, (uint)_stream.Length); This is progress though, I guess.

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• Issues loading Jquery (Galleria) script from inside an i-frame (beginner javascript?)

  - by 103188530284789248582

  Hello, first of all - I'm not entirely new to javascript, but am not fluent in it as I am with html and css, and am especially new to jQuery... so please excuse me if this questions seems easy or obvious, but after days of google I still have no solution to the problem... using jQuery 1.4.2.min, jQuery-ui-1.8.1 .... the site in question: http://homecapture.ca/sets/project_index.html The scenario: I have a tabbed menu generated from an unordered list, when a menu item is clicked it reveals an iframe which links to the page containing an image gallery. I am using jQuery UI tabs for the tabbed menu, and the galleries to which I'm linking are jQuery Galleria pages, automatically generated with Jalbum. The problem: The galleria plug-in only works normally from inside of the containing iframe in Chrome, has inconsistent behaviour in IE8 (seems to work in my local copy, but won't load properly online), and is not loaded properly in Firefox. Instead of displaying a thumbnail area and the first large image, the Galleria page shows the first thumbnail only, then when it is clicked the image it links to, but if you right-click and go Back, the iframe content shows up as a properly rendered Galleria page. Jalbum generates more script in the < head of the page in addition to linking to jquery and the galleria plug-in. All of it seems to be in charge of the gallery navigation , and I have relocated it to the < body of the page, in an effort to make it load after the parent page scripts, and together with the gallery content. At this point I am not sure what else I could do to solve the problem, without digging around in all or some of the library and pluging .js files (which I am not knowledgeable enough to do without some pointers). Has anyone dealt with a similar issue? I'm seeing some solutions for manipulating iframe content from a parent page with jQuery on here, is that what I should be researching instead? Thanks in advance for all the help! ps. I tried posting some code, but it seems I do not have enough 'reputation' for things to work right on here either :)

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• Parsing language for both binary and character files

  - by Thorsten S.

  The problem: You have some data and your program needs specified input. For example strings which are numbers. You are searching for a way to transform the original data in a format you need. And the problem is: The source can be anything. It can be XML, property lists, binary which contains the needed data deeply embedded in binary junk. And your output format may vary also: It can be number strings, float, doubles.... You don't want to program. You want routines which gives you commands capable to transform the data in a form you wish. Surely it contains regular expressions, but it is very good designed and it offers capabilities which are sometimes much more easier and more powerful. Something like a super-grep which you can access (!) as program routines, not only as tool. It allows: joining/grouping/merging of results inserting/deleting/finding/replacing write macros which allows to execute a command chain repeatedly meta-grouping (lists-tables-hypertables) Example (No, I am not looking for a solution to this, it is just an example): You want to read xml strings embedded in a binary file with variable length records. Your tool reads the record length and deletes the junk surrounding your text. Now it splits open the xml and extracts the strings. Being Indian number glyphs and containing decimal commas instead of decimal points, your tool transforms it into ASCII and replaces commas with points. Now the results must be stored into matrices of variable length....etc. etc. I am searching for a good language / language-design and if possible, an implementation. Which design do you like or even, if it does not fulfill the conditions, wouldn't you want to miss ? EDIT: The question is if a solution for the problem exists and if yes, which implementations are available. You DO NOT implement your own sorting algorithm if Quicksort, Mergesort and Heapsort is available. You DO NOT invent your own text parsing method if you have regular expressions. You DO NOT invent your own 3D language for graphics if OpenGL/Direct3D is available. There are existing solutions or at least papers describing the problem and giving suggestions. And there are people who may have worked and experienced such problems and who can give ideas and suggestions. The idea that this problem is totally new and I should work out and implement it myself without background knowledge seems for me, I must admit, totally off the mark.

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• jQuery 1.4.2 and IE6: change event not firing first time using keyboard

  - by macca1

  I've done a good amount of research on this and found a bunch of reported problems and solutions but the general consensus seems that all change problems in IE6 were fixed in jQuery 1.4.2. I'm having an issue where a change event is not firing in jQuery 1.4.2, but it did fire successfully in jQuery 1.3.2. This is in IE6. I'm about to submit a bug for this, but for my sanity I wanted to post it here first to see if there's something dumb I'm missing. I don't understand why this is working this way... <HTML> <HEAD> <TITLE>jQuery 1.4.2 Problem </TITLE> <script src="jquery-1.4.2.min.js" type="text/javascript"></script> <script> $(document).ready( function() { $("#firstBox").change(function() { alert("CHANGE"); }); // ONLOAD of document autofocus into the first element... $("form").find(":input:visible:first").focus() }); </script> </HEAD> <BODY> <form> <select id="firstBox"> <option value="" selected="selected">--</option> <option value="1">One</option> <option value="2">Two</option> </select> <br><br> <input size="10" id="secondBox"> </form> </BODY> </HTML> Simple enough, right? Onload of the page, give the first element focus. Onchange of the first element, alert. If you use the mouse, it works as expected. The page loads, the focus is in the drop down, you change the option, you get the alert. The problem is if you use the keyboard. The page loads, the focus is in the drop down, you press the down arrow. The option changes. Tab off the field, no alert. Weird. To make it even weirder, if you tab back into the field and change it again (all using the keyboard), the change event DOES fire after tab out this time. Any ideas?

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• RenderTargetBitmap + Resource'd VisualBrush = incomplete image

  - by Will

  I've found a new twist on the "Visual to RenderTargetBitmap" question! I'm rendering previews of WPF stuff for a designer. That means I need to take a WPF visual and render it to a bitmap without that visual ever being displayed. Got a nice little method to do it like to see it here it goes private static BitmapSource CreateBitmapSource(FrameworkElement visual) { Border b = new Border { Width = visual.Width, Height = visual.Height }; b.BorderBrush = Brushes.Black; b.BorderThickness = new Thickness(1); b.Background = Brushes.White; b.Child = visual; b.Measure(new Size(b.Width, b.Height)); b.Arrange(new Rect(b.DesiredSize)); RenderTargetBitmap rtb = new RenderTargetBitmap( (int)b.ActualWidth, (int)b.ActualHeight, 96, 96, PixelFormats.Pbgra32); // intermediate step here to ensure any VisualBrushes are rendered properly DrawingVisual dv = new DrawingVisual(); using (var dc = dv.RenderOpen()) { var vb = new VisualBrush(b); dc.DrawRectangle(vb, null, new Rect(new Point(), b.DesiredSize)); } rtb.Render(dv); return rtb; } Works fine, except for one leeetle thing... if my FrameworkElement has a VisualBrush, that brush doesn't end up in the final rendered bitmap. Something like this: <UserControl.Resources> <VisualBrush x:Key="LOLgo"> <VisualBrush.Visual> <!-- blah blah --> <Grid Background="{StaticResource LOLgo}"> <!-- yadda yadda --> Everything else renders to the bitmap, but that VisualBrush just won't show. The obvious google solutions have been attempted and have failed. Even the ones that specifically mention VisualBrushes missing from RTB'd bitmaps. I have a sneaky suspicion this might be caused by the fact that its a Resource, and that lazy resource isn't being inlined. So a possible fix would be to, somehow(???), force resolution of all static resource references before rendering. But I have absolutely no idea how to do that. Anybody have a fix for this?

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• Consolidating coding styles: Funcs, private method, single method classes

  - by jdoig

  Hi all, We currently have 3 devs with, some, conflicting styles and I'm looking for a way to bring peace to the kingdom... The Coders: Foo 1: Likes to use Func's & Action's inside public methods. He uses actions to alias off lengthy method calls and Func's to perform simple tasks that can be expressed in 1 or 2 lines and will be used frequently through out the code Pros: The main body of his code is succinct and very readable, often with only one or 2 public methods per class and rarely any private methods. Cons: The start of methods contain blocks of lambda rich code that other developers don't enjoy reading; and, on occasion, can contain higher order functions that other dev's REALLY don't like reading. Foo 2: Likes to create a private method for (almost) everything the public method will have to do . Pros: Public methods remain small and readable (to all developers). Cons: Private methods are numerous. With private methods that call into other private methods, that call into... etc, etc. Making code hard to navigate. Foo 3: Likes to create a public class with a, single, public method for every, non-trivial, task that needs performing, then dependency inject them into other objects. Pros: Easily testable, easy to understand (one object, one responsibility). Cons: project gets littered by classes, opening multiple class files to understand what code does makes navigation awkward. It would be great to take the best of all these techniques... Foo-1 Has really nice, readable (almost dsl-like) code... for the most part, except for all the Action and Func lambda shenanigans bulked together at the start of a method. Foo-3 Has highly testable and extensible code that just feels a bit "belt-&-braces" for some solutions and has some code-navigation niggles (constantly hitting F12 in VS and opening 5 other .cs files to find out what a single method does). And Foo-2... Well I'm not sure I like anything about the one-huge .cs file with 2 public methods and 12 private ones, except for the fact it's easier for juniors to dig into. I admit I grossly over-simplified the explanations of those coding styles; but if any one knows of any patterns, practices or diplomatic-manoeuvres that can help unite our three developers (without just telling any of them to just "stop it!") that would be great. From a feasibility standpoint : Foo-1's style meets with the most resistance due to some developers finding lambda and/or Func's hard to read. Foo-2's style meets with a less resistance as it's just so easy to fall into. Foo-3's style requires the most forward thinking and is difficult to enforce when time is short. Any ideas on some coding styles or conventions that can make this work?

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• generated service mock: everything but RhinoMocks fails?

  - by hko

  I have the "quest" to search for the next Mocking Framework for my company, and basically it's down to NSubstitute (simplest syntax, but no strict mocks), FakeItEasy(best reviews, Roy Osherove bonus, and slightly better lib support than NSubstitute), Moq (best "other libs support", biggest featureset, downside: mock.Object). We definitely want to move on from RhinoMocks, e.g. because of the unusefull interactiontest error messages (it should tell me what the parameter was instead, when a verification fails). So I was pretty surprised the other day (that was yesterday) when I found out RhinoMocks could do a thing where every other mock framework fails at: Mocking an autogenerated SomethingService (a typical VS autogenerated service with a default construtor in a partial class). Please don't argue about the design.. I intend to write lightweight integration tests (and some unit tests), and I can't mess around with the service, the product is installed on too many customers system. See this code: // here the NSubstitute and FakeItEasy equivalents throw an exception.. see below TicketStoreService fakeTicketStoreService = MockRepository.GenerateMock<TicketStoreService>(); fakeTicketStoreService.Expect(service => service.DoSomething(Arg.Is(new Guid())).Return(new Guid()); fakeTicketStoreService.DoSomething(Arg.Is(new Guid())); fakeTicketStoreService.VerifyAllExpectations(); Note that DoSomething is a non-virtual methodcall in an autogenerated class. So it shouldn't work, according to common knowledge. But it does. Problem is that it's the only (non commercial) framework that can do this: Rhino.Mocks works, and verification works too FakeItEasy says it doesn't find a default constructor (probably just wrong exception message): No default constructor was found on the type SomeNamespace.TicketStoreService Moq gives something sane and understandable: Invalid setup on a non-virtual (overridable in VB) member: service=> service.DoSomething Nsubstitute gives a message System.NotSupportedException: Cannot serialize member System.ComponentModel.Component.Site of type System.ComponentModel.ISite because it is an interface. I'm really wondering what's going on here with the frameworks, except Moq. The "fancy new" frameworks seem to have an initial perf hit too, probably preparing some Type cache and serializing stuff, whilst RhinoMocks somehow manages to create a very "slim" mock without recursion. I have to admit I didn't like RhinoMocks very well, but here it shines.. unfortunately. So, is there a way to get that to work with newer (non-commercial!) mocking frameworks, or somehow get a sane error message out of Rhino.Mocks? And why can Rhino.Mocks achieve this, when clearly every Mocking framework states it can only work with virtual methods when given a concrete class? Let's not derail the discussion by talking about alternative approaches like Extract&Override or runtime-proxy Mocking frameworks like JustMock/TypeMock/Moles or the new Fakes framework, I know these, but that would be less ideal solutions, for reasons beyond this topic. Any help appreciated..

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• Yet another Ant + JUnit classpath problem

  - by user337591

  Hi, I'm developing an Eclipse SWT application using Eclipse. There are also some JUnit 4 tests, which test some DAO's. But when I try to run the tests via an ant build, all of the tests fail, because the test classes aren't found. Google brought up about a million of people who all have the same problem, but none of their solutions seem to work for me -.- . These are the contents of my build.xml file: <property name="test.reports" value="./test/reports" /> <property name="classes" value="build" /> <path id="project.classpath"> <pathelement location="${classes}" /> </path> <target name="testreport"> <mkdir dir="${test.reports}" /> <junit fork="yes" printsummary="no" haltonfailure="no"> <batchtest fork="yes" todir="${test.reports}" > <fileset dir="${classes}"> <include name="**/Test*.class" /> </fileset> </batchtest> <formatter type="xml" /> <classpath refid="project.classpath" /> </junit> <junitreport todir="${test.reports}"> <fileset dir="${test.reports}"> <include name="TEST-*.xml" /> </fileset> <report todir="${test.reports}" /> </junitreport> </target> The test classes are in the build-directory together with the application classes, although they are in some subfolders according to their packages. Maybe this is important too: At first Ant complained that JUnit wasn't in its classpath, but since I put it there (with the eclipse configuration editor) it complains about JUnit being in its classpath twice. WARNING: multiple versions of ant detected in path for junit [junit] jar:file:C:/Users/as df/Documents/eclipse/plugins/org.apache.ant_1.7.1.v20090120-1145/lib/ant.jar!/org/apache/tools/ant/Project.class [junit] and jar:file:/C:/Users/as%20df/Documents/eclipse/plugins/org.apache.ant_1.7.1.v20090120-1145/lib/ant.jar!/org/apache/tools/ant/Project.class I've tried specifying each and every subdirectory, each and every class file, I've tried filesets and filelists, nothing seems to work. Thanks for your help, I've been sitting for hours on this thing now...

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• How can I specify resources in an MVVM view model?

  - by gix

  Suppose I want to show list of objects where each object should have a name and a suitable image (for example MenuItems with Icons, or buttons with text and image). All examples and programs exposed the image in the viewmodel as a path to a PNG file and then bound the Source of an Image to that. But what if I want to use vector images (for example as a DrawingImage in a local ResourceDictionary)? Exposing the DrawingImage from the view model seems bad because I would have to store a reference to the application/window/user control/... (and it is advised to not expose such XAML objects from view models). So a better approach would be to use a string identifier in the view model and then somehow select the appropriate resource. If that identifier is the resource key this snippet looks tempting but does not work: <Image Source="{StaticResource {Binding Icon}}"/> I found two workarounds for that though they did not work for me. The first one was using a normal binding to the icon with a converter that looked up the resource in Application.Current. This does not work if the resource is stored somewhere else I think (and the situation where I initially bumped into this problem had no Application running yet since it was a Window choosing the Application to launch!). The second workaround was using a markup extension derived from StaticResourceExtension that fetched its ResourceKey from the passed binding: <Image Source="{local:BindableStaticResource {Binding Icon}"/> This one looks really neat because it could use local resources, also be used for other things. But when using it I always got an exception ("Resource named {FooIcon} could not be found.", showing the correct XAML file and position of the extension). Even an empty resource extension derived from StaticResourceExtension that just passed the resource key to the base constructor did not work and I cannot explain why. Just using StaticResourceExtension worked just fine. Any ideas how I could fix the second approach, or even better solutions? Edit I noticed that it does work when used directly like this: <Window> <Window.Resources> <DrawingImage x:Key="SomeIcon"/> </Window.Resources> <Image Source="{BindableStaticResource {Binding Icon}}"/> </Window> but fails for example in a DataTemplate. Though a normal StaticResourceExtension works on both occasions so I am puzzled what is going wrong.

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• Handling exceptions raised in observers

  - by sparky

  I have a Rails (2.3.5) application where there are many groups, and each Group has_many People. I have a Group edit form where users can create new people. When a new person is created, they are sent an email (the email address is user entered on the form). This is accomplished with an observer on the Person model. The problem comes when ActionMailer throws an exception - for example if the domain does not exist. Clearly that cannot be weeded out with a validation. There would seem to be 2 ways to deal with this: A begin...rescue...end block in the observer around the mailer. The problem with this is that the only way to pass any feedback to the user would be to set a global variable - as the observer is out of the MVC flow, I can't even set a flash[:error] there. A rescue_from in the Groups controller. This works fine, but has 2 problems. Firstly, there is no way to know which person threw the exception (all I can get is the 503 exception, no way to know which person caused the problem). This would be useful information to be able to pass back to the user - at the moment, there is no way for me to let them know which email address is the problem - at the moment, I just have to chuck the lot back at them, and issue an unhelpful message saying that one of them is not correct. Secondly (and to a certain extent this make the first point moot) it seems that it is necessary to call a render in the rescue_from, or it dies with a rather bizarre "can't convert Array into String" error from webbrick, with no stack trace & nothing in the log. Thus, I have to throw it back to the user when I come across the first error and have to stop processing the rest of the emails. Neither of the solutions are optimal. It would seem that the only way to get Rails to do what I want is option 1, and loathsome global variables. This would also rely on Rails being single threaded. Can anyone suggest a better solution to this problem?

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• Autocomplete server-side implementation

  - by toluju

  What is a fast and efficient way to implement the server-side component for an autocomplete feature in an html input box? I am writing a service to autocomplete user queries in our web interface's main search box, and the completions are displayed in an ajax-powered dropdown. The data we are running queries against is simply a large table of concepts our system knows about, which matches roughly with the set of wikipedia page titles. For this service obviously speed is of utmost importance, as responsiveness of the web page is important to the user experience. The current implementation simply loads all concepts into memory in a sorted set, and performs a simple log(n) lookup on a user keystroke. The tailset is then used to provide additional matches beyond the closest match. The problem with this solution is that it does not scale. It currently is running up against the VM heap space limit (I've set -Xmx2g, which is about the most we can push on our 32 bit machines), and this prevents us from expanding our concept table or adding more functionality. Switching to 64-bit VMs on machines with more memory isn't an immediate option. I've been hesitant to start working on a disk-based solution as I am concerned that disk seek time will kill performance. Are there possible solutions that will let me scale better, either entirely in memory or with some fast disk-backed implementations? Edits: @Gandalf: For our use case it is important the the autocompletion is comprehensive and isn't just extra help for the user. As for what we are completing, it is a list of concept-type pairs. For example, possible entries are [("Microsoft", "Software Company"), ("Jeff Atwood", "Programmer"), ("StackOverflow.com", "Website")]. We are using Lucene for the full search once a user selects an item from the autocomplete list, but I am not yet sure Lucene would work well for the autocomplete itself. @Glen: No databases are being used here. When I'm talking about a table I just mean the structured representation of my data. @Jason Day: My original implementation to this problem was to use a Trie, but the memory bloat with that was actually worse than the sorted set due to needing a large number of object references. I'll read on the ternary search trees to see if it could be of use.

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• How could I send live video stream to remote server from my phone !!!

  - by poc

  Hello , I have a problem about streaming my video to server in real-time from my phone. that is , let my phone be a IP Camera , and server can watch the live video from my phone I have googled many many solutions, but there is no one can solve my problem. I use MediaRecorder to record . it can save video file in the SD card correctly. then , I refered this page and used some method as followings skt = new Socket(InetAddress.getByName(hostname),port); pfd =ParcelFileDescriptor.fromSocket(skt); mediaRecorder.setOutputFile(pfd.getFileDescriptor()); now it seems I can send the video stream while recording however, I wrote a receiver-side program to receive the video stream from Android , but it doesn't work . is there any error? I can receive file , but I can not open the video file . I guess the problem may caused by file format ? there are outline of my code. in android side Socket skt = new Socket(hostIP,port); ParcelFileDescriptor pfd =ParcelFileDescriptor.fromSocket(skt); .... .... mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC); mediaRecorder.setVideoSource(MediaRecorder.VideoSource.DEFAULT); mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4); mediaRecorder.setOutputFile(pfd.getFileDescriptor()); ..... mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.DEFAULT); mediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP); ..... mediaRecorder.start(); in receiver side (my ACER notebook) // anyway , I don't think the file extentions will do any effect File video = new File (strDate+".3gpp"); FileOutputStream fos; try { fos = new FileOutputStream(video); byte[] data = new byte[1024]; int count =-1; while( (count = fin.read(data,0,1024) ) !=-1) { fos.write(data,0,count); fos.flush(); } fos.close(); fin.close(); I confused a long time.... thanks in advance

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• If Then Statement Condition Being Ignored With Optimisations On

  - by Matma

  I think im going mad but can some show me what im missing, it must be some stupidly simple i just cant see the wood for the trees. BOTH side of this if then else statement are being executed? Ive tried commenting out the true side and moving the condition to a seperate variable with the same result. However if i explicitly set the condition to 1=0 or 1=1 then the if then statement is operating as i would expect. i.e. only executing one side of the equation... The only time ive seen this sort of thing is when the compiler has crashed and is no longer compiling (without visible indication that its not) but ive restarted studio with the same results, ive cleaned the solution, built and rebuilt with no change? please show me the stupid mistake im making using vs2005 if it matters. Dim dset As DataSet = New DataSet If (CboCustomers.SelectedValue IsNot Nothing) AndAlso (CboCustomers.SelectedValue <> "") Then Dim Sql As String = "Select sal.SalesOrderNo As SalesOrder,cus.CustomerName,has.SerialNo, convert(varchar,sal.Dateofpurchase,103) as Date from [dbo].[Customer_Table] as cus " & _ " inner join [dbo].[Hasp_table] as has on has.CustomerID=cus.CustomerTag " & _ " inner join [dbo].[salesorder_table] as sal On sal.Hasp_ID =has.Hasp_ID Where cus.CustomerTag = '" & CboCustomers.SelectedValue.ToString & "'" Dim dap As SqlDataAdapter = New SqlDataAdapter(Sql, FormConnection) dap.Fill(dset, "dbo.Customer_Table") DGCustomer.DataSource = dset.Tables("dbo.Customer_Table") Else Dim erm As String = "wtf" End If EDIT: i have found that this is something to do with the release config settings im using, i guesing its the optimisations bit. does anyone know of any utils/addons for vs that show if a line has been optimised out. delphi, my former language showed blue dots in the left margin to show that it was a compiled line, no dot meaning it wasnt compiled in, is there anything like that for vs? alternatively can someone explain how optimisations would affect this simple if statement causeing it to run both sides? EDIT2: using this thread as possible causes/solutions : http://stackoverflow.com/questions/2135509/bug-only-occurring-when-compile-optimization-enabled. It does the same with release = optimisations on, x86, x64 and AnyCPU Goes away with optimisations off. Im using V2005 on a x64 win7 machine, if that matters. Thanks

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• Is there any alternative to obfuscation to make it harder to get any string in javascript?

  - by MarceloRamires

  I use DropBox and I've had some trouble reaching to my files from other computers: I not always want to login to anything when I'm in a public computer, but I like being able to reach my stuff from wherever I am. So I've made a simple little application that when put in the public folder, ran and given the right UID, creates (still in your public folder) an HTML of all the content in the folder (including subfolders) as a tree of links. But I didn't risk loading it anywhere, since there are slightly private things in there (yes, I know that the folder's name is "PUBLIC"). So I've came up with the idea to make it a simple login page, given the right password, the rest of the page should load. brilliant!, but how? If I did this by redirecting to other HTML on the same folder, I'd still put the html link in the web history and the "url's accessed" history of the administrator. So I should generate itin the same page. I've done it. And currently the page is a textbox and a button, and only if you type in the right password (asked by the generator) the rest of the page loads. The fault is that everything (password, URL's) is easily reachable through the sourcecode. Now, assuming I only want to avoid silly people to get it all too easily, not make a bulletproof all-content-holding NSA certified website, I though about some ways to make these informations a bit harder to get. As you may have already figured, I use a streamwritter to write a .HTM file (head, loop through links, bottom), then it's extremely configurable, and I can come up with a pretty messy-but-working c# code, though my javascript knowledge is not that good. Public links in DropBox look like this: http://dl.dropbox.com/u/3045472/img.png Summarizing: How do I hide stuff (MAINLY the password, of course) in my source-code so that no bumb-a-joe that can read, use a computer and press CTRL+U can reach to my stuff too easily ? PS.: It's not that personal, if someone REALLY wants it, it could never be 100% protected, and if it was that important, I wouldnt put it in the public folder, also, if the dude really wants to get it that hard, he should deserve it. PS2.: "Use the ultra-3000'tron obfuscator!!11" is not a real answer, since my javascript is GENERATED by my c# program. PS3.: I don't want other solutions as "use a serverside application and host it somewhere to redirect and bla bla" or "compress the links in a .RAR file and put a password in it" since I'm doing this ALSO to learn, and I want the thrill of it =)

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• How to properly downcast in C# with a SWIG generated interface?

  - by JG

  I've got a very large and mature C++ code base that I'm trying to use SWIG on to generate a C# interface for. I cannot change the actual C++ code itself but we can use whatever SWIG offers in the way of extending/updating it. I'm facing an issue where a function C++ is written as such: A* SomeClass::next(A*) The caller might do something like: A* acurr = 0; while( (acurr = sc->next(acurr)) != 0 ){ if( acurr isoftype B ){ B* b = (B*)a; ...do some stuff with b.. } elseif( acurr isoftype C ) ... } Essentially, iterating through a container elements that depending on their true type, do something different. The SWIG generated C# layer for the "next" function unfortunately does the following: return new A(); So the calling code in C# land cannot determine if the returned object is actually a derived class or not, it actually appears to always be the base class (which does make sense). I've come across several solutions: Use the %extend SWIG keyword to add a method on an object and ultimately call dynamic_cast. The downside to this approach, as I see it, is that this requires you to know the inheritance hierarchy. In my case it is rather huge and I see this is as a maintenance issue. Use the %factory keyword to supply the method and the derived types and have SWIG automatically generate the dynamic_cast code. This appears to be a better solution that the first, however upon a deeper look it still requires you to hunt down all the methods and all the possible derived types it could return. Again, a huge maintenance issue. I wish I had a doc link for this but I can't find one. I found out about this functionality by looking through the example code that comes with SWIG. Create a C# method to create an instance of the derived object and transfer the cPtr to the new instance. While I consider this clumsy, it does work. See an example below. public static object castTo(object fromObj, Type toType) { object retval = null; BaseClass fromObj2 = fromObj as BaseClass; HandleRef hr = BaseClass.getCPtr(fromObj2); IntPtr cPtr = hr.Handle; object toObj = Activator.CreateInstance(toType, cPtr, false); // make sure it actually is what we think it is if (fromObj.GetType().IsInstanceOfType(toObj)) { return toObj; } return retval; } Are these really the options? And if I'm not willing to dig through all the existing functions and class derivations, then I'm left with #3? Any help would be appreciated.

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• A scheme for expiring downloaded content?

  - by Chad Johnson

  I am going to offer a web API service that allows users to download and "rent" content for a monthly subscription fee. The API will either be open to everyone or possibly just select parties (not sure yet). Each developer must agree to a license, and they receive a developer key for their person. Each software application will have its own key as well. So then end-users will download the software which will interact with my service's API. Each user will have a key for each application as well (probably using OAuth). Content will be cached on first download and accessible offline via just the third-party application that cached the content. If a user cancels their subscription, I plan on doing the following: Deactivate the user's OAuth key for all applications. Do not allow the user's account to download new content via the API (and subsequently any software that uses the API). Now, the big question is: how do I make content expire if they cancel their subscription? If they cancel, they should not have access to content anymore. Here are ideas I've thought of (some of these are half-solutions, not yet fully fleshed out): Require that applications encrypt downloaded content using the user's OAuth key, making it available to only the application. This will prevent most users from going to the cache directory and just copying and keeping files. Update the user's key once a month, forcing content to re-cache on a monthly basic. Users could then access content for a month after they cancel their subscription. Require applications to "phone home" [to the service] periodically and check whether the user's subscription has terminated. If so, require in the API developer license that applications expire cache. If it is found that applications do not comply, their keys (and possibly keys for all developers) are permanently deactivated as a consequence. One major worry is that some applications may blatantly ignore constraints of the license. Is it generally acceptable to rely on applications abiding by the licensing constraints? Bad idea? Any other ideas? Maybe a way to make content auto-expire after x days? Something else? I'm open to out-of-the-box ideas.

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• How to do the processing and keep GUI refreshed using databinding?

  - by macias

  History of the problem This is continuation of my previous question How to start a thread to keep GUI refreshed? but since Jon shed new light on the problem, I would have to completely rewrite original question, which would make that topic unreadable. So, new, very specific question. The problem Two pieces: CPU hungry heavy-weight processing as a library (back-end) WPF GUI with databinding which serves as monitor for the processing (front-end) Current situation -- library sends so many notifications about data changes that despite it works within its own thread it completely jams WPF data binding mechanism, and in result not only monitoring the data does not work (it is not refreshed) but entire GUI is frozen while processing the data. The aim -- well-designed, polished way to keep GUI up to date -- I am not saying it should display the data immediately (it can skip some changes even), but it cannot freeze while doing computation. Example This is simplified example, but it shows the problem. XAML part: <StackPanel Orientation="Vertical"> <Button Click="Button_Click">Start</Button> <TextBlock Text="{Binding Path=Counter}"/> </StackPanel> C# part (please NOTE this is one piece code, but there are two sections of it): public partial class MainWindow : Window,INotifyPropertyChanged { // GUI part public MainWindow() { InitializeComponent(); DataContext = this; } private void Button_Click(object sender, RoutedEventArgs e) { var thread = new Thread(doProcessing); thread.IsBackground = true; thread.Start(); } // this is non-GUI part -- do not mess with GUI here public event PropertyChangedEventHandler PropertyChanged; public void OnPropertyChanged(string property_name) { if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs(property_name)); } long counter; public long Counter { get { return counter; } set { if (counter != value) { counter = value; OnPropertyChanged("Counter"); } } } void doProcessing() { var tmp = 10000.0; for (Counter = 0; Counter < 10000000; ++Counter) { if (Counter % 2 == 0) tmp = Math.Sqrt(tmp); else tmp = Math.Pow(tmp, 2.0); } } } Known workarounds (Please do not repost them as answers) Those two first are based on Jon ideas: pass GUI dispatcher to library and use it for sending notifications -- why it is ugly? because it could be no GUI at all give up with data binding COMPLETELY (one widget with databinding is enough for jamming), and instead check from time to time data and update the GUI manually -- well, I didn't learn WPF just to give up with it now ;-) and this is mine, it is ugly, but simplicity of it kills -- before sending notification freeze a thread -- Thread.Sleep(1) -- to let the potential receiver "breathe" -- it works, it is minimalistic, it is ugly though, and it ALWAYS slows down computation even if no GUI is there So... I am all ears for real solutions, not some tricks.

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• Sanity Check: change event not firing first time using keyboard

  - by macca1

  I've done a good amount of research on this and found a bunch of reported problems and solutions but the general consensus seems that all change problems in IE6 were fixed in jQuery 1.4.2. I'm having an issue where a change event is not firing in jQuery 1.4.2, but it did fire successfully in jQuery 1.3.2. This is in IE6. I'm about to submit a bug for this, but for my sanity I wanted to post it here first to see if there's something dumb I'm missing. I don't understand why this is working this way... <HTML> <HEAD> <TITLE>jQuery 1.4.2 Problem </TITLE> <script src="jquery-1.4.2.min.js" type="text/javascript"></script> <script> $(document).ready( function() { $("#firstBox").change(function() { alert("CHANGE"); }); // ONLOAD of document autofocus into the first element... $("form").find(":input:visible:first").focus() }); </script> </HEAD> <BODY> <form> <select id="firstBox"> <option value="" selected="selected">--</option> <option value="1">One</option> <option value="2">Two</option> </select> <br><br> <input size="10" id="secondBox"> </form> </BODY> </HTML> Simple enough, right? Onload of the page, give the first element focus. Onchange of the first element, alert. If you use the mouse, it works as expected. The page loads, the focus is in the drop down, you change the option, you get the alert. The problem is if you use the keyboard. The page loads, the focus is in the drop down, you press the down arrow. The option changes. Tab off the field, no alert. Weird. To make it even weirder, if you tab back into the field and change it again (all using the keyboard), the change event DOES fire after tab out this time. Any ideas?

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• SVN: Branches for Every Little Change?

  - by yar

  Hi. We have a client (who has a client, who has a client) who is driving us mad with change requests to a code base (in PHP). Our first response was to just work in a main trunk in SVN, but the client often comes back and requests that a certain change needs to get pushed to the live servers ASAP. On the other hand, other changes get reduced in priority suddenly, which originally came grouped with other changes (seemingly). We are thinking of using a branch for every change request. Is this mad? What other solutions might work? Thanks! Edit: This is a really hard question to choose the correct answer for. Thanks to everybody for your great answers. Edit: I know that the best answer I chose was not particularly popular. I too wanted to find a technical solution to this problem. But now I think that if the client wants software with features that can be deployed in a modular fashion... this problem should not be solved in our use of the version control system. It would have to be designed into the software. Edit: Now it's almost a month later and my coworker/client has convinced me that multiple branches is the way to go. This is not just due to the client's insanity, but also based on our need to be able to determine if a feature is "ready to go" or "needs more work" or whatever. I don't have the SVN with me, but we merge using the advice from the SVN Cookbook: you merge the branch from the revision it was branched to the head revision. Also, using this system, we merge all branches at some point and that becomes the new QA and then live build. Then we branch from that. Last Edit (Perhaps): Months later, this system is still working out for us. We create branches for every ticket and rarely have problems. On the other hand, we do try to keep things separate as far as what people are working on... Two Years Later: We use GIT now, and now this system is actually quite reasonable.

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• Finding N contiguous zero bits in an integer to the left of the MSB position of another integer

  - by James Morris

  The problem is: given an integer val1 find the position of the highest bit set (Most Significant Bit) then, given a second integer val2 find a contiguous region of unset bits, with the minimum number of zero bits given by width to the left of the position (ie, in the higher bits). Here is the C code for my solution: typedef unsigned int t; unsigned const t_bits = sizeof(t) * CHAR_BIT; _Bool test_fit_within_left_of_msb( unsigned width, t val1, t val2, unsigned* offset_result) { unsigned offbit = 0; unsigned msb = 0; t mask; t b; while(val1 >>= 1) ++msb; while(offbit + width < t_bits - msb) { mask = (((t)1 << width) - 1) << (t_bits - width - offbit); b = val2 & mask; if (!b) { *offset_result = offbit; return true; } if (offbit++) /* this conditional bothers me! */ b <<= offbit - 1; while(b <<= 1) offbit++; } return false; } Aside from faster ways of finding the MSB of the first integer, the commented test for a zero offbit seems a bit extraneous, but necessary to skip the highest bit of type t if it is set. I have also implemented similar algorithms but working to the right of the MSB of the first number, so they don't require this seemingly extra condition. How can I get rid of this extra condition, or even, are there far more optimal solutions? Edit: Some background not strictly required. The offset result is a count of bits from the high bit, not from the low bit as maybe expected. This will be part of a wider algorithm which scans a 2D array for a 2D area of zero bits. Here, for testing, the algorithm has been simplified. val1 represents the first integer which does not have all bits set found in a row of the 2D array. From this the 2D version would scan down which is what val2 represents. Here's some output showing success and failure: t_bits:32 t_high: 10000000000000000000000000000000 ( 2147483648 ) --------- ----------------------------------- *** fit within left of msb test *** ----------------------------------- val1: 00000000000000000000000010000000 ( 128 ) val2: 01000001000100000000100100001001 ( 1091569929 ) msb: 7 offbit:0 + width: 8 = 8 mask: 11111111000000000000000000000000 ( 4278190080 ) b: 01000001000000000000000000000000 ( 1090519040 ) offbit:8 + width: 8 = 16 mask: 00000000111111110000000000000000 ( 16711680 ) b: 00000000000100000000000000000000 ( 1048576 ) offbit:12 + width: 8 = 20 mask: 00000000000011111111000000000000 ( 1044480 ) b: 00000000000000000000000000000000 ( 0 ) offbit:12 iters:10 ***** found room for width:8 at offset: 12 ***** ----------------------------------- *** fit within left of msb test *** ----------------------------------- val1: 00000000000000000000000001000000 ( 64 ) val2: 00010000000000001000010001000001 ( 268469313 ) msb: 6 offbit:0 + width: 13 = 13 mask: 11111111111110000000000000000000 ( 4294443008 ) b: 00010000000000000000000000000000 ( 268435456 ) offbit:4 + width: 13 = 17 mask: 00001111111111111000000000000000 ( 268402688 ) b: 00000000000000001000000000000000 ( 32768 ) ***** mask: 00001111111111111000000000000000 ( 268402688 ) offbit:17 iters:15 ***** no room found for width:13 ***** (iters is the count of iterations of the inner while loop)

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• Coroutines in Java

  - by JUST MY correct OPINION

  I would like to do some stuff in Java that would be clearer if written using concurrent routines, but for which full-on threads are serious overkill. The answer, of course, is the use of coroutines, but there doesn't appear to be any coroutine support in the standard Java libraries and a quick Google on it brings up tantalising hints here or there, but nothing substantial. Here's what I've found so far: JSIM has a coroutine class, but it looks pretty heavyweight and conflates, seemingly, with threads at points. The point of this is to reduce the complexity of full-on threading, not to add to it. Further I'm not sure that the class can be extracted from the library and used independently. Xalan has a coroutine set class that does coroutine-like stuff, but again it's dubious if this can be meaningfully extracted from the overall library. It also looks like it's implemented as a tightly-controlled form of thread pool, not as actual coroutines. There's a Google Code project which looks like what I'm after, but if anything it looks more heavyweight than using threads would be. I'm basically nervous of something that requires software to dynamically change the JVM bytecode at runtime to do its work. This looks like overkill and like something that will cause more problems than coroutines would solve. Further it looks like it doesn't implement the whole coroutine concept. By my glance-over it gives a yield feature that just returns to the invoker. Proper coroutines allow yields to transfer control to any known coroutine directly. Basically this library, heavyweight and scary as it is, only gives you support for iterators, not fully-general coroutines. The promisingly-named Coroutine for Java fails because it's a platform-specific (obviously using JNI) solution. And that's about all I've found. I know about the native JVM support for coroutines in the Da Vinci Machine and I also know about the JNI continuations trick for doing this. These are not really good solutions for me, however, as I would not necessarily have control over which VM or platform my code would run on. (Indeed any bytecode manipulation system would suffer similar problems -- it would be best were this pure Java if possible. Runtime bytecode manipulation would restrict me from using this on Android, for example.) So does anybody have any pointers? Is this even possible? If not, will it be possible in Java 7?

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• Java app makes screen display unresponsive after 10 minutes of user idle time

  - by Ross

  I've written a Java app that allows users to script mouse/keyboard input (JMacro, link not important, only for the curious). I personally use the application to automate character actions in an online game overnight while I sleep. Unfortunately, I keep coming back to the computer in the morning to find it unresponsive. Upon further testing, I'm finding that my application causes the computer to become unresponsive after about 10 minutes of user idle time (even if the application itself it simulating user activity). I can't seem to pin-point the issue, so I'm hoping somebody else might have a suggestion of where to look or what might be causing the issue. The relevant symptoms and characteristics: Unresponsiveness occurs after user is idle for 10 minutes User can still move the mouse pointer around the screen Everything but the mouse appears frozen... mouse clicks have no effect and no applications update their displays, including the Windows 7 desktop I left the task manager up along the with the app overnight so I could see the last task manager image before the screen freezes... the Java app is at normal CPU/Memory usage and total CPU usage is only ~1% After moving the mouse (in other words, the user comes back from being idle), the screen image starts updating again within 30 minutes (this is very hit and miss... sometimes 10 minutes, sometimes no results after two hours) User can CTRL-ALT-DEL to get to Windows 7's CTRL-ALT-DEL screen (after a 30 second pause). User is still able to move mouse pointer, but clicking any of the button options causes the screen to appear to freeze again On some very rare occasions, the system never freezes, and I come back to it in the morning with full responsiveness The Java app automatically stops input scripting in the middle of the night, so Windows 7 detects "real" idleness and turns the monitors into Standby mode... which they successfully come out of upon manually moving the mouse in the morning when I wake up, even though the desktop display still appears frozen Given the symptoms and characteristics of the issue, it's as if the Java app is causing the desktop display of the logged in user to stop updating, including any running applications. Programming concepts and Java packages used: Multi-threading Standard out and err are rerouted to a javax.swing.JTextArea The application uses a Swing GUI awt.Robot (very heavily used) awt.PointerInfo awt.MouseInfo System Specs: Windows 7 Professional Java 1.6.0 u17 In conclusion, I should stress that I'm not looking for any specific solutions, as I'm not asking a very specific question. I'm just wondering if anybody has run into a similar problem when using the Java libraries that I'm using. I would also gladly appreciate any suggestions for things to try to attempt to further pinpoint what is causing my problem. Thanks! Ross PS, I'll post an update/answer if I manage to stumble across anything else while I continue to debug this.

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• Using pointers, references, handles to generic datatypes, as generic and flexible as possible

  - by Patrick

  In my application I have lots of different data types, e.g. Car, Bicycle, Person, ... (they're actually other data types, but this is just for the example). Since I also have quite some 'generic' code in my application, and the application was originally written in C, pointers to Car, Bicycle, Person, ... are often passed as void-pointers to these generic modules, together with an identification of the type, like this: Car myCar; ShowNiceDialog ((void *)&myCar, DATATYPE_CAR); The 'ShowNiceDialog' method now uses meta-information (functions that map DATATYPE_CAR to interfaces to get the actual data out of Car) to get information of the car, based on the given data type. That way, the generic logic only has to be written once, and not every time again for every new data type. Of course, in C++ you could make this much easier by using a common root class, like this class RootClass { public: string getName() const = 0; }; class Car : public RootClass { ... }; void ShowNiceDialog (RootClass *root); The problem is that in some cases, we don't want to store the data type in a class, but in a totally different format to save memory. In some cases we have hundreds of millions of instances that we need to manage in the application, and we don't want to make a full class for every instance. Suppose we have a data type with 2 characteristics: A quantity (double, 8 bytes) A boolean (1 byte) Although we only need 9 bytes to store this information, putting it in a class means that we need at least 16 bytes (because of the padding), and with the v-pointer we possibly even need 24 bytes. For hundreds of millions of instances, every byte counts (I have a 64-bit variant of the application and in some cases it needs 6 GB of memory). The void-pointer approach has the advantage that we can almost encode anything in a void-pointer and decide how to use it if we want information from it (use it as a real pointer, as an index, ...), but at the cost of type-safety. Templated solutions don't help since the generic logic forms quite a big part of the application, and we don't want to templatize all this. Additionally, the data model can be extended at run time, which also means that templates won't help. Are there better (and type-safer) ways to handle this than a void-pointer? Any references to frameworks, whitepapers, research material regarding this?

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