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• MVVM pattern: ViewModel updates after Model server roundtrip

  - by Pavel Savara

  I have stateless services and anemic domain objects on server side. Model between server and client is POCO DTO. The client should become MVVM. The model could be graph of about 100 instances of 20 different classes. The client editor contains diverse tab-pages all of them live-connected to model/viewmodel. My problem is how to propagate changes after server round-trip nice way. It's quite easy to propagate changes from ViewModel to DTO. For way back it would be possible to throw away old DTO and replace it whole with new one, but it will cause lot of redrawing for lists/DataTemplates. I could gather the server side changes and transmit them to client side. But the names of fields changed would be domain/DTO specific, not ViewModel specific. And the mapping seems nontrivial to me. If I should do it imperative way after round-trip, it would break SOC/modularity of viewModels. I'm thinking about some kind of mapping rule engine, something like automappper or emit mapper. But it solves just very plain use-cases. I don't see how it would map/propagate/convert adding items to list or removal. How to identify instances in collections so it could merge values to existing instances. As well it should propagate validation/error info. Maybe I should implement INotifyPropertyChanged on DTO and try to replay server side events on it ? And then bind ViewModel to it ? Would binding solve the problems with collection merges nice way ? Is EventAgregator from PRISM useful for that ? Is there any event record-replay component ? Is there better client side pattern for architecture with server side logic ?

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• How to implement menuitems that depend on current selection in WPF MVVM explorer-like application

  - by Doug

  I am new to WPF and MVVM, and I am working on an application utilizing both. The application is similar to windows explorer, so consider an app with a main window with menu (ShellViewModel), a tree control (TreeViewModel), and a list control (ListViewModel). I want to implement menu items such as Edit - Delete, which deletes the currently selected item (which may be in the tree or in the list). I am using Josh Smith's RelayCommand, and binding the menuitem to a DeleteItemCommand in the ShellViewModel is easy. It seems like implementing the DeleteItemCommand, however, requires some fairly tight coupling between the ShellViewModel and the two child view models (TreeViewModel and ListViewModel) to keep track of the focus/selection and direct the action to the proper child for implementation. That seems wrong to me, and makes me think I'm missing something. Writing a focus manager and/or selection manager to do the bookkeeping does not seem too hard, and could be done without coupling the classes together. The windowing system is already keeping track of which view has the focus, and it seems like I'd be duplicating code. What I'm not sure about is how I would route the command from the ShellViewModel down to either the ListViewModel or the TreeViewModel to do the actual work without making a mess of the code. Some day, the application will be extended to include more than two children, and I want the shell to be as ignorant of the children as possible to make that extension as painless as possible. Looking at some sample WPF/MVVM applications (Karl Shifflett's CipherText, Josh Smith's MVVM Demo, etc.), I haven't seen any code that does this (or I didn't understand it). Regardless of whether you think my approach is way off base or I'm just missing a small nuance, please share your thoughts and help me get back on track. Thanks!

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• Service Browser for AMF calls (Flex to Java)

  - by Tehsin

  Has anyone used or is aware of a service browser to test AMF calls? I am looking for a tool similar to ZamfBrowser ( http://www.zamfbrowser.org ), but one that works for the Java environment. ZamfBrowser is geared towards AMFPHP. The idea here is to provide a service browser, that allows developers to test Java services using the AMF protocol, without having to go through the Flex UI all the time. There has got to be something out there already for this, but I can't seem to locate anything..... It's kind of funny and strange that a service browser exists for AMFPHP but not for regular AMF calls in a Java environment. I would imagine something exists under Blaze or LCDS? ... Trying to find it in the docs but can't seem to find anything .... The best alternative I can think of at the moment is to use FlexMonkey to record stuff, and then to simulate it using that....which is okay I guess but still sucks because you have to go in and create the Flex UI first, whereas with something like ZamfBrowser, you simply point it at the service calls, it tells the server-side developers if their code works, etc. generates the required as3 classes for you... and makes the integration process much easier in a large team. Any help or insight would be appreciated :) Thanks!

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• Nusphere PHPEd: PHP Function Hints Lost Arguments?

  - by Eli

  Hi All, My PHPEd suddenly stopped showing arguments and arg order in the hints, and now just shows a basic description of the function. Before I go digging around in the config files, has anyone else had this problem? Thanks! Edit: Sorry, I may not have been entirely clear on this. There is no problem with my own classes, only with the actual php functions. Example: How it used to work: I type a PHP function, say strpos. As soon as I type the '(' at the end of it, I get the little yellow box, showing something like this: int strpos ( string $haystack , mixed $needle [, int $offset=0 ] ) with the first argument bold. If I type it, and then a comma, it bolds the second arg, and so on. This is really nice, since PHP functions are a bit scrambled as far as argument order, and I don't have to look them up every time. How it works now: I type a php function, say strpos. As soon as I type the '(' at the end of it, I get the little yellow box. It says something like "strpos - Returns the numeric position of the first occurrence of needle in the haystack string." There are no arguments shown, which makes the little box basically worthless - I know what strpos does, I just want a reminder of the argument order. I think this may be a problem with the included PHPDoc, which I never use, but may be the source of the data for the hint box. I did recently upgrade to 5.6, but ended up removing it and restoring 5.2. I installed to a different folder, and uninstalled from there, but it may have overwritten something in the original folder? I'm using v5.2 (5220). Thanks!

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• How to use javascript class from within document ready

  - by Richard

  Hi, I have this countdown script wrapped as an object located in a separate file Then when I want to setup a counter, the timeout function in the countdown class can not find the object again that I have setup within the document ready. I sort of get that everything that is setup in the document ready is convined to that scope, however it is possible to call functions within other document ready´s. Does anyone has a solution on how I could setup multiple counters slash objects. Or do those basic javascript classes have to become plugins This is some sample code on how the class begins function countdown(obj) { this.obj = obj; this.Div = "clock"; this.BackColor = "white"; this.ForeColor = "black"; this.TargetDate = "12/31/2020 5:00 AM"; this.DisplayFormat = "%%D%% Days, %%H%% Hours, %%M%% Minutes, %%S%% Seconds."; this.CountActive = true; this.DisplayStr; this.Calcage = cd_Calcage; this.CountBack = cd_CountBack; this.Setup = cd_Setup; } thanks, Richard

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• Is there an MVVM-friendly way to swap views without value converters firing unnecessarily?

  - by DanM

  I thought what I was doing was right out of the Josh Smith MVVM handbook, but I seem to be having a lot of problems with value converters firing when no data in the view-model has changed. So, I have a ContentControl defined in XAML like this: <ContentControl Grid.Row="0" Content="{Binding CurrentViewModel}" /> The Window containing this ContentControl references a resource dictionary that looks something like this: <ResourceDictionary ...> <DataTemplate DataType="{x:Type lib_vm:SetupPanelViewModel}"> <lib_v:SetupPanel /> </DataTemplate> <DataTemplate DataType="{x:Type lib_vm:InstructionsPanelViewModel}"> <lib_v:InstructionsPanel /> </DataTemplate> </ResourceDictionary> So, basically, the two data templates specify which view to show with which view-model. This switches the views as expected whenever the CurrentViewModel property on my window's view-model changes, but it also seems to cause value converters on the views to fire even when no data has changed. It's a particular problem with IMultiValueConverter classes, because the values in the value array get set to DependencyProperty.UnsetValue, which causes exceptions unless I specifically check for that. But I'm getting other weird side effects too. This has me wondering if I shouldn't just do everything manually, like this: Instantiate each view. Set the DataContext of each view to the appropriate view-model. Give the ContentControl a name and make it public. Handle the PropertyChanged event for the window. In the event handler, manually set the Content property of the ContentControl to the appropriate view, based the CurrentViewModel (using if statements). This seems to work, but it also seems very inelegant. I'm hoping there's a better way. Could you please advise me the best way to handle view switching so that value converters don't fire unnecessarily?

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• SQL Alchemy MVC and cross controller joins

  - by Khorkrak

  When using SQL Alchemy for abstracting your data access layer and using controllers as the way to access objects from that abstraction layer, how should joins be handled? So for example, say you have an Orders controller class that manages Order objects such that it provides getOrder, saveOrder, etc methods and likewise a similar controller for User objects. First of all do you even need these controllers? Should you instead just treat SQL Alchemy as "the" thing for handling data access. Why bother with object oriented controller stuff there when you instead have a clean declarative way to obtain and persist objects without having to write SQL directly either. Well one reason could be that perhaps you may want to replace SQL Alchemy with direct SQL or Storm or whatever else. So having controller classes there to act as an intermediate layer helps limit what would need to change then. Anyway - back to the main question - so assuming you have these two controllers, now lets say you want the list of orders for a certain set of users meeting some criteria. How do you go about doing this? Generally you don't want the controllers crossing domains - the Orders controllers knows only about Orders and the User controller just about Users - they don't mess with each other. You also don't want to go fetch all the Users that match and then feed a big list of user ids to the Orders controller to go find the matching Orders. What's needed is a join. Here's where I'm stuck - that seems to mean either the controllers must cross domains or perhaps they should be done away with altogether and you simply do the join via SQL Alchemy directly and get the resulting User and / or Order objects as needed. Thoughts?

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• Java - encrypt / decrypt user name and password from a configuration file

  - by nzpcmad

  We are busy developing a Java web service for a client. There are two possible choices: Store the encrypted user name / password on the web service client. Read from a config. file on the client side, decrypt and send. Store the encrypted user name / password on the web server. Read from a config. file on the web server, decrypt and use in the web service. The user name / password is used by the web service to access a third-party application. The client already has classes that provide this functionality but this approach involves sending the user name / password in the clear (albeit within the intranet). They would prefer storing the info. within the web service but don't really want to pay for something they already have. (Security is not a big consideration because it's only within their intranet). So we need something quick and easy in Java. Any recommendations? The server is Tomkat 5.5. The web service is Axis2. What encrypt / decrypt package should we use? What about a key store? What configuration mechanism should we use? Will this be easy to deploy?

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• Design problem with callback functions in android

  - by Franz Xaver

  Hi folks! I'm currently developing an app in android that is accessing wifi values, that is, the application needs to scan for all access point and their specific signal strengths. I know that I have to extend the class BroadcastReceiver overwriting the method BroadcastReceiver.onReceive(Context context, Intent intent) which is called when the values are ready. Perhaps there exist solutions provided by the android system itself but I'm relatively new to android so I could need some help. The problem I encountered is that I got one class (an activity, thus controlled by the user) that needs this scan results for two different things (first to save the values in a database or second, to use them for further calculations but not both at one moment!) So how to design the callback system in order to "transport" the scan results from onReceive(Context context, Intent intent) to the operation intended by the user? My first solution was to define enums for each use case (save or use for calculations) which wlan-interested classes have to submit when querying for the values. But that would force the BroadcastReceiverextending class to save the current enum and use it as a parameter in the callback function of the querying class (this querying class needs to know what it asked for when getting backcalled) But that seems to me kind of dirty ;) So anyone a good idea for this?

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• Build number increment not reflected in AssemblyVersion

  - by awshepard

  I've browsed through some of the discussion on auto-incrementing build numbers, but in the impatience of youth decided to roll my own and re-invent the wheel. I know there are probably better ways to go about this (which I'm definitely going to investigate), but my question centers more around the Assembly and/or Version classes. My approach was to write a separate exe (BuildIncrementer) that takes a command line parameter for file name, does a regex match on the contents to grab the [assembly: AssemblyVersion...] string, do the modifications that I want (increment the build number, etc.), then write the contents back to the file. This approach works as-is. The next thing I did was in the project that I wanted to use this on, I set up a pre-build command line that is simply the command to execute that BuildIncrementer.exe on this project's AssemblyInfo.cs file. This too works, updating the assembly info as desired. The problem comes when I run the project, it sends an email containing the current version, obtained with Assembly.GetExecutingAssembly().GetName().Version.ToString(). BUT, the version showing up is the previous version. When my AssemblyInfo.cs says [assembly: AssemblyVersion("1.0.2.49667")], I get sent 1.0.1.45660, which was the previous build. Anyone have any ideas why that might be?

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• How do I fix a broken connection to DB2 from a web application?

  - by Eddie White

  I support some old web applications, VBScript-based ASP for the UI and VB6 COM modules for the business and data access layers. Last weekend, I installed DB2 Connect Enterprise Edition v8 fixpack 14 on several Windows 2000 servers, and one of the web apps errors out on null data when it calls the built in VBScript function FormatNumber. This numeric data is retrieved by a SQL Server query, but the only way the SQL Server column is populated is with the calculated results returned from a DB2 query earlier in a progression through several pages. When I installed DB2 Connect EE, one of the components loaded was MDAC 2.7. I followed corporate instructions and had the installation save an ODBC System Data Source, which reported a good connection when I tested it after the install. For what it's worth, the project references in the production VB6 modules pointed to MDAC 2.5. I have tried recompiling and deploying to COM on my test server new versions of the VB6 modules referencing MDAC 2.7. My development environment is Windows XP Pro, with MDAC 2.8 and DB2 Connect EE v9.5 installed. When I deployed the updated VB6 dlls, the CreateObject fails to instantiate the classes with the error message that "The class does not support automation or the requested interface". I've rolled the DB2 Connect install back and have reinstall v8 of the DB2 runtime client, which was the previous environment. The problem, however, persists.

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• How to tell axis2 to use an existing object as a service?

  - by Christian Hausknecht

  I am trying to expose some methods of a running application as a webservice. The core idea is to use an embedded web-server and send the soap messages to the apache axis2 framework in order to invoke the services. The problem is, that axis2's createService methods only accept Classes as parameter, not existing objects. So I believe that axis2 itself creates an object of the service class and then uses it to call methods when an external service call arrives. But I need to pass an existing object for being used as a service, because I need to call methods of other objects of the running application within the service methods. So the "standard" way that axis2 creates a new instance of the service class and calls then its methods is obviously no sulution for me. So is there a way to realize this? Or is there another solution? Perhaps you can pass objects later on to the allready created service object by axis2? If there is another solution without axis2 I might consider that one. Basically I am only interested in exposing some functionality of a runnning application as a webservice.

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• How large a role does subjectiveness play in programming?

  - by Bob

  I often read about the importance of readability and maintainability. Or, I read very strong opinions about which syntax features are bad or good. Or discussions about the values of certain paradigms, like OOP. Aside from that, this same question floats about in my mind whenever I read debates on SO or Meta about subjective questions. Or read questions about best practices and sometimes find myself or others disagreeing. What role does subjectiveness play within the programming realm? Sometimes I think it plays a large role. Software developers are engineers in a way, but also people. A large part of programming is dealing with code that's human readable. This is very different from Math or Physics or other disciplines with very exact and structured rules. Here the exact structure and rules are largely up in the air, changeable on a whim, and hence the amount of languages in existence. And one person may find one language very readable, and another person may find their own language the most comforting. The same with practices. One person may not like certain accepted practices. I myself find splitting classes into different files very unreadable, for instance. But, I can't say rules haven't helped in general. Certain practices have and do make life easier. And new languages have given rise to syntax and structure that make life easier. There's certainly been a progression towards code that is easier to read and maintain even given a largely diverse group of people. So maybe these things aren't as subjective as I thought. It reminds me, in a way, of UI design. Certainly it's subjective, but then there's an entire discipline involved in crafting good UI and it tends to work. Is there something non-subjective about the ideas behind maintainability, readability, and other best practices? Is there something tangible to grasp when one develops a new language or thinks of new practices?

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• Maven jaxb generate plugin to read xsd files from multiple directories

  - by ziggy

  If i have xsd file in the following directories src/main/resources/xsd src/main/resources/schema/common src/main/resources/schema/soap How can i instruct the maven jaxb plugin to generate jaxb classes using all schema files in the above directory? I can get it to generate the class files if i specify one of the folders but i cant get i dont know how to include all three folders. Here is how i generate the files for one folder: <plugin> <groupId>org.jvnet.jaxb2.maven2</groupId> <artifactId>maven-jaxb2-plugin</artifactId> <executions> <execution> <goals> <goal>generate</goal> </goals> </execution> </executions> <configuration> <schemaDirectory>src/main/resources/xsd</schemaDirectory> </configuration> </plugin> I tried adding multiple entries in the element but it just ignores all of them if i do that. Thanks

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• Disassembler that tracks what value is where

  - by Martin C. Martin

  So lately I've been looking at the disassembly of my C++ code, and having to manually track what's in each register, like this: 95: 48 8b 16 mov (%rsi),%rdx ; %rdx = raggedCross.sink 98: 48 8b 42 38 mov 0x38(%rdx),%rax ; %rax = sink.table 9c: 8b 4a 10 mov 0x10(%rdx),%ecx ; %ecx = sink.baseCol 9f: 48 8b 70 50 mov 0x50(%rax),%rsi ; %rsi = table.starts a3: 89 c8 mov %ecx,%eax ; %eax = baseCol a5: 83 c1 1c add $0x1c,%ecx ; %ecx = baseCol + 1 And so on. The comments are mine, added by hand, from looking up the offset of various fields (e.g. sink, table, baseCol, starts) in the C++ classes. It's straight forward to do, but tedius and time consuming: the perfect thing for a program to be doing. gdb seems to know the offset of various fields within a struct: I can do &((Table *)0x1200)-starts and it tells the the right address. So, this information is around. Is there some disassembler that can use this info to annotate the code for me? Failing that, I could write my own. Where does gdb get the offsets?

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• SecurityManager StackOverflowError

  - by Tom Brito

  Running the following code, I get a StackOverflowError at the getPackage() line. How can I grant permission just to classes inside package I want, if I can't access the getPackage() to check the package? package myPkg.security; import java.security.Permission; import javax.swing.JOptionPane; public class SimpleSecurityManager extends SecurityManager { @Override public void checkPermission(Permission perm) { Class<?>[] contextArray = getClassContext(); for (Class<?> c : contextArray) { checkPermission(perm, c); } } @Override public void checkPermission(Permission perm, Object context) { if (context instanceof Class) { Class clazz = (Class) context; Package pkg = clazz.getPackage(); // StackOverflowError String name = pkg.getName(); if (name.startsWith("java.")) { // permission granted return; } if (name.startsWith("sun.")) { // permission granted return; } if (name.startsWith("myPkg.")) { // permission granted return; } } // permission denied throw new SecurityException("Permission denied for " + context); } public static void main(String[] args) { System.setSecurityManager(new SimpleSecurityManager()); JOptionPane.showMessageDialog(null, "test"); } }

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• Get notified when objective-c dom updates are ready initiated from webview

  - by Josh

  I am programmatically updating the DOM on a WebKit webview via DOMElement objects - for complex UI, there is usually a javascript component to any element that I add. This begs the need to be notified when the updates complete -- is there any such event? I know regular divs dont fire an onload or onready event, correct? The other assumption I had, which may be totally wrong, is that DOMElement updates aren't synchronous, so I can't do something like this and be confident it will meet with the label actually in the DOM: DOMElement *displayNameLabel = [document createElement:@"div"]; [displayNameLabel setAttribute:@"class" value:@"user-display-name"]; [displayNameLabel setTextContent:currentAvatar.avatarData.displayName]; [[document getElementById:@"user-card-content"] appendChild:displayNameLabel]; id win = [webView windowScriptObject]; [win evaluateWebScript:@"javascriptInstantiateLabel()"]; Is this true? I am using jquery within the body of the html already, so I don't mind subscribing to a particular classes set of events via "live." I thought I might be able to do something like: $(".some-class-to-be-added-later").live( "ready", function(){ // Instantiate some fantastic javascript here for .some-class }); but have experienced no joy so far. Is there any way on either side (objective-c since I don't programmatically firing javascript post load, or javascript) to be notified when the element is in the DOM? Thanks, Josh

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• Best Practice With JFrame Constructors?

  - by David Barry

  In both my Java classes, and the books we used in them laying out a GUI with code heavily involved the constructor of the JFrame. The standard technique in the books seems to be to initialize all components and add them to the JFrame in the constructor, and add anonymous event handlers to handle events where needed, and this is what has been advocated in my class. This seems to be pretty easy to understand, and easy to work with when creating a very simple GUI, but seems to quickly get ugly and cumbersome when making anything other than a very simple gui. Here is a small code sample of what I'm describing: public class FooFrame extends JFrame { JLabel inputLabel; JTextField inputField; JButton fooBtn; JPanel fooPanel; public FooFrame() { super("Foo"); fooPanel = new JPanel(); fooPanel.setLayout(new FlowLayout()); inputLabel = new JLabel("Input stuff"); fooPanel.add(inputLabel); inputField = new JTextField(20); fooPanel.add(inputField); fooBtn = new JButton("Do Foo"); fooBtn.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent e) { //handle event } }); fooPanel.add(fooBtn); add(fooPanel, BorderLayout.CENTER); } } Is this type of use of the constructor the best way to code a Swing application in java? If so, what techniques can I use to make sure this type of constructor is organized and maintainable? If not, what is the recommended way to approach putting together a JFrame in java?

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• How do I find Microsoft APIs?

  - by Stephen

  I'm a java programmer, and if I see something that: I don't know about or just want to find a method description without opening an ide or am on support I type java [classname] into google, and there it is. If I try this crazy stunt for C# I'll come up with a whole heap of tutorials (how do I use it etc). If I manage to get to MSDN, I have to wade through a page describing every .net technology to see how their syntax references the same object, and then I have to find the appropriate page from there ([class name] Constructor) for example. This is even more pronounced, because I don't have Visual Studio, so I've got nothing to make it easier. There must be something I'm missing or don't know... how does this situation work for Microsoft developers? how can I make my life easier/searches better? are there techniques that work no matter what computer I'm on (e.g. require no computer setup/downloads) Notes It could be thought that java is just "java", but it's just that the java apis are only referenced/defined in the core language. For all the other languages on the JVM, it's assumed that you will just learn the correct syntax to use the java apis. I presume that .Net only lists a whole heap of languages as the api classes are actually different and have different interfaces capabilities (or some approximation of this presumption). Edit While searching msdn works... in the java space I can type 'java [anyclass]' and it will generally be found... whether it's a java core api or a third party library

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• Pass Variable to Java Method from an Ant Target

  - by user200317

  At the moment I have a .properties file to store settings related to the framework. Example: default.auth.url=http://someserver-at008:8080/ default.screenshots=false default.dumpHTML=false And I have written a class to extract those values and here is the method of that class. public static String getResourceAsStream(String defaultProp) { String defaultPropValue = null; //String keys = null; try { InputStream inputStream = SeleniumDefaultProperties.class.getClassLoader().getResourceAsStream(PROP_FILE); Properties properties = new Properties(); //load the input stream using properties. properties.load(inputStream); defaultPropValue = properties.getProperty(defaultProp); }catch (IOException e) { log.error("Something wrong with .properties file, check the location.", e); } return defaultPropValue; } Throughout the application I use method like follows to just exact property needed, public String getBrowserDefaultCommand() { String bcmd = SeleniumDefaultProperties.getResourceAsStream("default.browser.command"); if(bcmd.equals("")) handleMissingConfigProperties(SeleniumDefaultProperties.getResourceAsStream("default.browser.command")); return bcmd; } But I have not decided do a change to this and use ant and pass a parameter instead of using it from .properties file. I was wondering how could I pass a value to a Java Method using ANT. Non of these classes have Main methods and will not have any main. Due to this I was unable to use it as a java system properties. Thanks in advance.

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• RegularExpression-esque search matching Objects in List

  - by Pindatjuh

  I'm currently working on an implementation of the following idea, and I was wondering if there is any literature on this subject. Working with Java, but the principle applies on any language with a decent type-system, I like to implement: matching Objects from a List using a RegularExpression-esque search: So let's say I have a List containing List<Object> x = new ArrayList<Object>(); x.add(new Object()); x.add("Hello World"); x.add("Second String"); x.add(5); // Integer (auto-boxing) x.add(6); // Integer Then I create a "Regular Expression" (not working with a stream of characters, but working with a stream of Objects), and instead of character-classes, I use type-system properties: [String][Integer] And this would match one sublist: {Match["Second String", 5]}. The expression: [String:length()<15] Will match two sublist (each of length 1) containing a String which instance is passing the expression instance.length() < 5: {Match["Hello World"],Match["Second String"]}. [Object][Object] Matches any pair in the List: {Match[Object,"Hello World"],Match["Second String", 5]}, in a streamed manner (no overlapping matches). Ofcourse, my implementation will have grouping, lookahead/lookbehinds and is hierarchical (i.e. matching n elements from Lists in Lists), etc. The above merely illustrates the concept. Is there a name for this principle, and is there literature available on it?

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• What are the best workarounds for known problems with Hibernate's schema validation of floating poin

  - by Jason Novak

  I have several Java classes with double fields that I am persisting via Hibernate. For example, I have @Entity public class Node ... private double value; When Hibernate's org.hibernate.dialect.Oracle10gDialect creates the DDL for the Node table, it maps the value field to a "double precision" type. create table MDB.Node (... value double precision not null, ... It would appear that in Oracle, "double precision" is an alias for "float". So, when I try to verify the database schema using the org.hibernate.cfg.AnnotationConfiguration.validateSchema() method, Oracle appears to describe the value column as a "float". This causes Hibernate to throw the following Exception org.hibernate.HibernateException: Wrong column type in DBO.ACL_RULE for column value. Found: float, expected: double precision A very similar problem is listed in Hibernate's JIRA database as HHH-1961 (http://opensource.atlassian.com/projects/hibernate/browse/HHH-1961). I'd like to avoid doing anything that will break MySql, Postgres, and Sql Server support so extending the Oracle10gDialect appears to be the most promising of the workarounds mentioned in HHH-1961. But extending a Dialect is something I've never done before and I'm afraid there may be some nasty gotchas. What is the best workaround for this problem that won't break our compatibility with MySql, Postgres, and Sql Server? Thanks for taking the time to look at this!

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• Should I remove all inheritance from my model in order to work with ria services?

  - by TimothyP

  I've posted some questions on this before, but it's different. So consider a small portion of our model: Person Customer Employee Spouse Person is the base class which has 3 classes that inherit from it. These 4 are very central in our design and link to many other entities. I could solve all the problems I'm experiencing with ria-services by removing the inheritance but that would really increase the complexety of the model. The first problem I experienced was that I couldn't query for Customers, Employees or Spouses, but someone gave me a solution, which was to add something like this to the DomainService: public IQueryable<Employee> GetEmployees() { return this.ObjectContext.People.OfType<Employee>(); } public IQueryable<Customer> GetCustomers() { return this.ObjectContext.People.OfType<Customer>(); } public IQueryable<Spouse> GetSpouses() { return this.ObjectContext.People.OfType<Spouse>(); } Next I tried something that seemed very normal to me: var employee = new Employee() { //.... left out to reduce the length of this question }; var spouse = new Spouse() { //.... left out to reduce the length of this questions }; employee.Spouse = spouse; context.People.Add(spouse); context.People.Add(employee); context.SubmitChanges(); Then I get the following exception: Cannot retrieve an entity set for the derived entity type 'Spouse'. Use EntityContainer.GetEntitySet(Type) to get the entity set for the base entity type 'Person'. Even when the spouse is already in the database, and I retreive it first I get similar exceptions. Also note that for some reason in some places "Persons" is used instead of "People"... So how do I solve this problem, what am I doing wrong and will I keep running into walls when using ria services with inheritance? I found some references on the web, all saying it works and then some DomainService code in which they suposedly changed something but no details... I'm using VS2010 RC1 + Silveright 4

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• [EF 4 POCO] Problem with INSERT...

  - by Darmak

  Hi all, I'm so frustrated because of this problem, you have no idea... I have 2 classes: Post and Comment. I use EF 4 POCO support, I don't have foreign key columns in my .edmx model (Comment class doesn't have PostID property, but has Post property) class Comment { public Post post { get; set; } // ... } class Post { public virtual ICollection<Comment> Comments { get; set; } // ... } Can someone tell me why the code below doesn't work? I want to create a new comment for a post: Comment comm = context.CreateObject<Comment>(); Post post = context.Posts.Where(p => p.Slug == "something").SingleOrDefault(); // post != null, so don't worry, be happy // here I set all other comm properties and... comm.Post = post; context.AddObject("Comments", comm); // Exception here context.SaveChanges(); The Exception is: Cannot insert the value NULL into column 'PostID', table 'Blog.Comments'; column does not allow nulls. INSERT fails. ... this 'PostID' column is of course a foreign key to the Posts table. Any help will be appreciated!

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• SubSonic generated code and always filtering records

  - by cmroanirgo

  Hi, I have a table called "Users" that has a column called "deleted", a boolean indicating that the user is "Deleted" from the system (without actually deleting it, of course). I also have a lot of tables that have a FK to the Users.user_id column. Subsonic generates (very nicely) the code for all the foreign keys in a similar manner: public IQueryable<person> user { get { var repo=user.GetRepo(); return from items in repo.GetAll() where items.user_id == _user_id select items; } } Whilst this is good and all, is there a way to generate the code in such a way to always filter out the "Deleted" users too? In the office here, the only suggestion we can think of is to use a partial class and extend it. This is obviously a pain when there are lots and lots of classes using the User table, not to mention the fact that it's easy to inadvertently use the wrong property (User vs ActiveUser in this example): public IQueryable<User> ActiveUser { get { var repo=User.GetRepo(); return from items in repo.GetAll() where items.user_id == _user_id and items.deleted == 0 select items; } } Any ideas?

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