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  • Memory allocation in java

    - by Girish
    class Someobject { int i=10; } public class OtherObject { public static void main(String args[]) { Someobject obj=new Someobject(); System.out.println(obj.i); } } Please tell me in which section of the memory: This entire code will load. Where will someobject will be stored. Where will obj will be stored Where will i be stored. Thanks every one in advance.

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  • User Control as container at design time

    - by Luca
    I'm designing a simple expander control. I've derived from UserControl, drawn inner controls, built, run; all ok. Since an inner Control is a Panel, I'd like to use it as container at design time. Indeed I've used the attributes: [Designer(typeof(ExpanderControlDesigner))] [Designer("System.Windows.Forms.Design.ParentControlDesigner, System.Design", typeof(IDesigner))] Great I say. But it isn't... The result is that I can use it as container at design time but: The added controls go back the inner controls already embedded in the user control Even if I push to top a control added at design time, at runtime it is back again on controls embedded to the user control I cannot restrict the container area at design time into a Panel area What am I missing? Here is the code for completeness... why this snippet of code is not working? [Designer(typeof(ExpanderControlDesigner))] [Designer("System.Windows.Forms.Design.ParentControlDesigner, System.Design", typeof(IDesigner))] public partial class ExpanderControl : UserControl { public ExpanderControl() { InitializeComponent(); .... [System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Demand, Name = "FullTrust")] internal class ExpanderControlDesigner : ControlDesigner { private ExpanderControl MyControl; public override void Initialize(IComponent component) { base.Initialize(component); MyControl = (ExpanderControl)component; // Hook up events ISelectionService s = (ISelectionService)GetService(typeof(ISelectionService)); IComponentChangeService c = (IComponentChangeService)GetService(typeof(IComponentChangeService)); s.SelectionChanged += new EventHandler(OnSelectionChanged); c.ComponentRemoving += new ComponentEventHandler(OnComponentRemoving); } private void OnSelectionChanged(object sender, System.EventArgs e) { } private void OnComponentRemoving(object sender, ComponentEventArgs e) { } protected override void Dispose(bool disposing) { ISelectionService s = (ISelectionService)GetService(typeof(ISelectionService)); IComponentChangeService c = (IComponentChangeService)GetService(typeof(IComponentChangeService)); // Unhook events s.SelectionChanged -= new EventHandler(OnSelectionChanged); c.ComponentRemoving -= new ComponentEventHandler(OnComponentRemoving); base.Dispose(disposing); } public override System.ComponentModel.Design.DesignerVerbCollection Verbs { get { DesignerVerbCollection v = new DesignerVerbCollection(); v.Add(new DesignerVerb("&asd", new EventHandler(null))); return v; } } } I've found many resources (Interaction, designed, limited area), but nothing was usefull for being operative... Actually there is a trick, since System.Windows.Forms classes can be designed (as usual) and have a correct behavior at runtime (TabControl, for example).

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  • Same data being returned by linq for 2 different executions of a stored procedure?

    - by Paul
    Hello I have a stored procedure that I am calling through Entity Framework. The stored procedure has 2 date parameters. I supply different argument in the 2 times I call the stored procedure. I have verified using SQL Profiler that the stored procedure is being called correctly and returning the correct results. When I call my method the second time with different arguments, even though the stored procedure is bringing back the correct results, the table created contains the same data as the first time I called it. dtStart = 01/08/2009 dtEnd = 31/08/2009 public List<dataRecord> GetData(DateTime dtStart, DateTime dtEnd) { var tbl = from t in db.SP(dtStart, dtEnd) select t; return tbl.ToList(); } GetData((new DateTime(2009, 8, 1), new DateTime(2009, 8, 31)) // tbl.field1 value = 45450 - CORRECT GetData(new DateTime(2009, 7, 1), new DateTime(2009, 7, 31)) // tbl.field1 value = 45450 - WRONG 27456 expected Is this a case of Entity Framework being clever and caching? I can't see why it would cache this though as it has executed the stored procedure twice. Do I have to do something to close tbl? using Visual Studio 2008 + Entity Framework. I also get the message "query cannot be enumerated more than once" a few times every now and then, am not sure if that is relevant? FULL CODE LISTING namespace ProfileDataService { public partial class DataService { public static List<MeterTotalConsumpRecord> GetTotalAllTimesConsumption(DateTime dtStart, DateTime dtEnd, EUtilityGroup ug, int nMeterSelectionType, int nCustomerID, int nUserID, string strSelection, bool bClosedLocations, bool bDisposedLocations) { dbChildDataContext db = DBManager.ChildDataConext(nCustomerID); var tbl = from t in db.GetTotalConsumptionByMeter(dtStart, dtEnd, (int) ug, nMeterSelectionType, nCustomerID, nUserID, strSelection, bClosedLocations, bDisposedLocations, 1) select t; return tbl.ToList(); } } } /// CALLER List<MeterTotalConsumpRecord> _P1Totals; List<MeterTotalConsumpRecord> _P2Totals; public void LoadData(int nUserID, int nCustomerID, ELocationSelectionMethod locationSelectionMethod, string strLocations, bool bIncludeClosedLocations, bool bIncludeDisposedLocations, DateTime dtStart, DateTime dtEnd, ReportsBusinessLogic.Lists.EPeriodType durMainPeriodType, ReportsBusinessLogic.Lists.EPeriodType durCompareToPeriodType, ReportsBusinessLogic.Lists.EIncreaseReportType rptType, bool bIncludeDecreases) { ///Code for setting properties using parameters.. _P2Totals = ProfileDataService.DataService.GetTotalAllTimesConsumption(_P2StartDate, _P2EndDate, EUtilityGroup.Electricity, 1, nCustomerID, nUserID, strLocations, bIncludeClosedLocations, bIncludeDisposedLocations); _P1Totals = ProfileDataService.DataService.GetTotalAllTimesConsumption(_StartDate, _EndDate, EUtilityGroup.Electricity, 1, nCustomerID, nUserID, strLocations, bIncludeClosedLocations, bIncludeDisposedLocations); PopulateLines() //This fills up a list of objects with information for my report ready for the totals to be added PopulateTotals(_P1Totals, 1); PopulateTotals(_P2Totals, 2); } void PopulateTotals(List<MeterTotalConsumpRecord> objTotals, int nPeriod) { MeterTotalConsumpRecord objMeterConsumption = null; foreach (IncreaseReportDataRecord objLine in _Lines) { objMeterConsumption = objTotals.Find(delegate(MeterTotalConsumpRecord t) { return t.MeterID == objLine.MeterID; }); if (objMeterConsumption != null) { if (nPeriod == 1) { objLine.P1Consumption = (double)objMeterConsumption.Consumption; } else { objLine.P2Consumption = (double)objMeterConsumption.Consumption; } objMeterConsumption = null; } } } }

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  • C# Property Access vs Interface Implementation

    - by ehdv
    I'm writing a class to represent a Pivot Collection, the root object recognized by Pivot. A Collection has several attributes, a list of facet categories (each represented by a FacetCategory object) and a list of items (each represented by a PivotItem object). Therefore, an extremely simplified Collection reads: public class Collection { private List<FacetCategory> categories; private List<PivotItem> items; // other attributes } What I'm unsure of is how to properly grant access to those two lists. Because declaration order of both facet categories and items is visible to the user, I can't use sets, but the class also shouldn't allow duplicate categories or items. Furthermore, I'd like to make the Collection object as easy to use as possible. So my choices are: Have Collection implement IList<PivotItem> and have accessor methods for FacetCategory: In this case, one would add an item to Collection foo by writing foo.Add(bar). This works, but since a Collection is equally both kinds of list making it only pass as a list for one type (category or item) seems like a subpar solution. Create nested wrapper classes for List (CategoryList and ItemList). This has the advantage of making a consistent interface but the downside is that these properties would no longer be able to serve as lists (because I need to override the non-virtual Add method I have to implement IList rather than subclass List. Implicit casting wouldn't work because that would return the Add method to its normal behavior. Also, for reasons I can't figure out, IList is missing an AddRange method... public class Collection { private class CategoryList: IList<FacetCategory> { // ... } private readonly CategoryList categories = new CategoryList(); private readonly ItemList items = new ItemList(); public CategoryList FacetCategories { get { return categories; } set { categories.Clear(); categories.AddRange(value); } } public ItemList Items { get { return items; } set { items.Clear(); items.AddRange(value); } } } Finally, the third option is to combine options one and two, so that Collection implements IList<PivotItem> and has a property FacetCategories. Question: Which of these three is most appropriate, and why?

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  • WPF windows locked when calling webservice. Even when run asynchronously

    - by SumGuy
    Hi there. I'm having a big problem when calling a web service from my WPF application. The application/window locks until the process has completed. I've attempted to run this asynchronously but the problem still persists. Currently, the web service call I'm making can last 45-60 seconds. It runs a process on the server to fetch a big chunk of data. As it take a little while I wanted to have a progress bar moving indeterminately for the user to see that the application hasn't stalled or anything (you know how impatatient they get). So: private void btnSelect_Click(object sender, RoutedEventArgs e) { wDrawingList = new WindowDrawingList(systemManager); AsyncMethodHandler caller = default(AsyncMethodHandler); caller = new AsyncMethodHandler(setupDrawingList); // open new thread with callback method caller.BeginInvoke((Guid)((Button)sender).Tag, MyAsyncCallback, null); } Click a button and the app will create the form that the async stuff will be posted to and set up the async stuff calling the async method. public bool setupDrawingList(Guid ID) { if (systemManager.set(ID)) { wDrawingList.Dispatcher.Invoke(DispatcherPriority.Background, new Action(() => { wDrawingList.ShowForm(); Hide(); })); return true; } return false; } This is the async method. The showForm method contains the calls to setup the new form including the monster web service call public void MyAsyncCallback(IAsyncResult ar) { // Because you passed your original delegate in the asyncState parameter of the Begin call, you can get it back here to complete the call. MethodDelegate dlgt = (MethodDelegate)ar.AsyncState; // Complete the call. bool output = dlgt.EndInvoke(ar); try { // Retrieve the delegate. AsyncResult result = (AsyncResult)ar; AsyncMethodHandler caller = (AsyncMethodHandler)result.AsyncDelegate; // Because this method is running from secondary thread it can never access ui objects because they are created // on the primary thread. // Call EndInvoke to retrieve the results. bool returnValue = caller.EndInvoke(ar); // Still on secondary thread, must update ui on primary thread UpdateUI(returnValue == true ? "Success" : "Failed"); } catch (Exception ex) { string exMessage = null; exMessage = "Error: " + ex.Message; UpdateUI(exMessage); } } public void UpdateUI(string outputValue) { // Get back to primary thread to update ui UpdateUIHandler uiHandler = new UpdateUIHandler(UpdateUIIndicators); string results = outputValue; // Run new thread off Dispatched (primary thread) this.Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Normal, uiHandler, results); } public void UpdateUIIndicators(string outputValue) { // update user interface controls from primary UI thread sbi3.Content = "Processing Completed."; } Any help or theories are appreciated. I'm at a loss. Thanks in advance

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  • Autowire not working in junit test

    - by Dave Paroulek
    I'm sure I'm missing something simple. bar gets autowired in the junit test, but why doesn't bar inside foo get autowired? @RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration({"beans.xml"}) public class BarTest { @Autowired Object bar; @Test public void testBar() throws Exception { //this works assertEquals("expected", bar.someMethod()); //this doesn't work, because the bar object inside foo isn't autowired? Foo foo = new Foo(); assertEquals("expected", foo.someMethodThatUsesBar()); } }

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  • How to force Json.Net to put an integer value into a string field?

    - by Earlz
    Hello, in using Json.Net I have a class like this class Foo{ public string name; public string value; } and I have a JSON string that looks like this: [{"name": "some name","value": "1"}] The problem with this is that Json.Net detects "1" as being an integer(due to ambiguities with JSON) and will refuse to put it into the string value of Foo How can I override this behavior so that it will put the string "1" into value?

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  • Migrating from hand-written persistence layer to ORM

    - by Sergey Mikhanov
    Hi community, We are currently evaluating options for migrating from hand-written persistence layer to ORM. We have a bunch of legacy persistent objects (~200), that implement simple interface like this: interface JDBC { public long getId(); public void setId(long id); public void retrieve(); public void setDataSource(DataSource ds); } When retrieve() is called, object populates itself by issuing handwritten SQL queries to the connection provided using the ID it received in the setter (this usually is the only parameter to the query). It manages its statements, result sets, etc itself. Some of the objects have special flavors of retrive() method, like retrieveByName(), in this case a different SQL is issued. Queries could be quite complex, we often join several tables to populate the sets representing relations to other objects, sometimes join queries are issued on-demand in the specific getter (lazy loading). So basically, we have implemented most of the ORM's functionality manually. The reason for that was performance. We have very strong requirements for speed, and back in 2005 (when this code was written) performance tests has shown that none of mainstream ORMs were that fast as hand-written SQL. The problems we are facing now that make us think of ORM are: Most of the paths in this code are well-tested and are stable. However, some rarely-used code is prone to result set and connection leaks that are very hard to detect We are currently squeezing some additional performance by adding caching to our persistence layer and it's a huge pain to maintain the cached objects manually in this setup Support of this code when DB schema changes is a big problem. I am looking for an advice on what could be the best alternative for us. As far as I know, ORMs has advanced in last 5 years, so it might be that now there's one that offers an acceptable performance. As I see this issue, we need to address those points: Find some way to reuse at least some of the written SQL to express mappings Have the possibility to issue native SQL queries without the necessity to manually decompose their results (i.e. avoid manual rs.getInt(42) as they are very sensitive to schema changes) Add a non-intrusive caching layer Keep the performance figures. Is there any ORM framework you could recommend with regards to that?

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  • Alias for EditorAttribute

    - by Johan
    Is there a way to create a shorter alias for an EditorAttribute? Instead of: [EditorAttribute(typeof<ColorPickerDialogPropertyValueEditor>, typeof<DialogPropertyValueEditor>)] public Color4 Color { get; set; } I would like to write: using ColorPicker = EditorAttribute(typeof<ColorPickerDialogPropertyValueEditor>, typeof<DialogPropertyValueEditor>) [ColorPicker] public Color4 Color { get; set; } Unfortunately the EditorAttribute class is sealed so I cannot inherit it.

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  • Can't i set Session in a class file?

    - by uzay95
    Why session is null in this even if i set: public class HelperClass { public AtuhenticatedUser f_IsAuthenticated(bool _bRedirect) { HttpContext.Current.Session["yk"] = DAO.context.GetById<AtuhenticatedUser>(1); if (HttpContext.Current.Session["yk"] == null) { if (_bRedirect) { HttpContext.Current.Response.Redirect(ConfigurationManager.AppSettings["loginPage"] + "?msg=You have to login."); } return null; } return (AtuhenticatedUser)HttpContext.Current.Session["yk"]; } }

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  • Jython saying "No visible constructors for class"

    - by clutch
    I have a jython servlet as part of a large application running in tomcat5. I tested a few Spring Framework classes and create the objects in the Jython servlet. When I try to create objects of classes in the application I catch an Exception message "No visible constructors for class". These java classes do have a public constructor class, such as: public SchoolImpl() { } I create the object in python: from com.dc.sports.entity import SchoolImpl ... school = SchoolImpl() What am I doing wrong?

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  • PHP 'instanceof' failing with class constant

    - by Nathan Loding
    I'm working on a framework that I'm trying to type as strongly as I possibly can. (I'm working within PHP and taking some of the ideas that I like from C# and trying to utilize them within this framework.) I'm creating a Collection class that is a collection of domain entities/objects. It's kinda modeled after the List<T> object in .Net. I've run into an obstacle that is preventing me from typing this class. If I have a UserCollection, it should only allow User objects into it. If I have a PostCollection, it should only allow Post objects. All Collections in this framework need to have certain basic functions, such as add, remove, iterate. I created an interface, but found that I couldn't do the following: interface ICollection { public function add($obj) } class PostCollection implements ICollection { public function add(Post $obj) {} } This broke it's compliance with the interface. But I can't have the interface strongly typed because then all Collections are of the same type. So I attempted the following: interface ICollection { public function add($obj) } abstract class Collection implements ICollection { const type = 'null'; } class PostCollection { const type = 'Post'; public function add($obj) { if(!($obj instanceof self::type)) { throw new UhOhException(); } } } When I attempt to run this code, I get syntax error, unexpected T_STRING, expecting T_VARIABLE or '$' on the instanceof statement. A little research into the issue and it looks like the root of the cause is that $obj instanceof self is valid to test against the class. It appears that PHP doesn't process the entire self::type constant statement in the expression. Adding parentheses around the self::type variable threw an error regarding an unexpected '('. An obvious workaround is to not make the type variable a constant. The expression $obj instanceof $this->type works just fine (if $type is declared as a variable, of course). I'm hoping that there's a way to avoid that, as I'd like to define the value as a constant to avoid any possible change in the variable later. Any thoughts on how I can achieve this, or have I take PHP to it's limit in this regard? Is there a way of "escaping" or encapsulating self::this so that PHP won't die when processing it?

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  • check if directory exists c#

    - by Ant
    I am trying to see if a directory exists based on an input field from the user. When the user types in the path, I want to check if the path actually exists. I have some c# code already. It returns 1 for any local path, but always returns 0 when I am checking a network path. static string checkValidPath(string path) { //Insert your code that runs under the security context of the authenticating user here. using (ImpersonateUser user = new ImpersonateUser(user, "", password)) { //DirectoryInfo d = new DirectoryInfo(quotelessPath); bool doesExist = Directory.Exists(path); //if (d.Exists) if(doesExist) { user.Dispose(); return "1"; } else { user.Dispose(); return "0"; } } } public class ImpersonateUser : IDisposable { [DllImport("advapi32.dll", SetLastError = true)] private static extern bool LogonUser(string lpszUsername, string lpszDomain, string lpszPassword, int dwLogonType, int dwLogonProvider, out IntPtr phToken); [DllImport("kernel32", SetLastError = true)] private static extern bool CloseHandle(IntPtr hObject); private IntPtr userHandle = IntPtr.Zero; private WindowsImpersonationContext impersonationContext; public ImpersonateUser(string user, string domain, string password) { if (!string.IsNullOrEmpty(user)) { // Call LogonUser to get a token for the user bool loggedOn = LogonUser(user, domain, password, 9 /*(int)LogonType.LOGON32_LOGON_NEW_CREDENTIALS*/, 3 /*(int)LogonProvider.LOGON32_PROVIDER_WINNT50*/, out userHandle); if (!loggedOn) throw new Win32Exception(Marshal.GetLastWin32Error()); // Begin impersonating the user impersonationContext = WindowsIdentity.Impersonate(userHandle); } } public void Dispose() { if (userHandle != IntPtr.Zero) CloseHandle(userHandle); if (impersonationContext != null) impersonationContext.Undo(); } } Any help is appreciated. Thanks! EDIT 3: updated code to use BrokenGlass's impersonation functions. However, I need to initialize "password" to something... EDIT 2: I updated the code to try and use impersonation as suggested below. It still fails everytime. I assume I am using impersonation improperly... EDIT: As requested by ChrisF, here is the function that calls the checkValidPath function. Frontend aspx file... $.get('processor.ashx', { a: '7', path: x }, function(o) { alert(o); if (o=="0") { $("#outputPathDivValid").dialog({ title: 'Output Path is not valid! Please enter a path that exists!', width: 500, modal: true, resizable: false, buttons: { 'Close': function() { $(this).dialog('close'); } } }); } }); Backend ashx file... public void ProcessRequest (HttpContext context) { context.Response.Cache.SetExpires(DateTime.Now); string sSid = context.Request["sid"]; switch (context.Request["a"]) {//a bunch of case statements here... case "7": context.Response.Write(checkValidPath(context.Request["path"].ToString())); break;

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  • N2Cms, Adding a new property to a ContentPageBase class, corrupts the already entered data.

    - by Nour Sabouny
    i want to modify the ContentPageBase, in a functional site, i tried to add a property called for example (weight), but if there is an existing page in the database, the site will malfunction, and throws an Exception, of (Object reference not set to an instance of an object). how can i correct the already entered data ? public abstract class ContentPageBase : PageBase, ICommentable { [EditableTextBox("Weight", 10, ContainerName = Tabs.Details)] //newly added property. public virtual int Weight { get { return (int)GetDetail("Weight"); } set { SetDetail("Weight", value); } } }

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  • Why sockets does not die when server dies? Why socket dies when server is alive?

    - by Roman
    I try to play with sockets a bit. For that I wrote very simple "client" and "server" applications. Client: import java.net.*; public class client { public static void main(String[] args) throws Exception { InetAddress localhost = InetAddress.getLocalHost(); System.out.println("before"); Socket clientSideSocket = null; try { clientSideSocket = new Socket(localhost,12345,localhost,54321); } catch (ConnectException e) { System.out.println("Connection Refused"); } System.out.println("after"); if (clientSideSocket != null) { clientSideSocket.close(); } } } Server: import java.net.*; public class server { public static void main(String[] args) throws Exception { ServerSocket listener = new ServerSocket(12345); while (true) { Socket serverSideSocket = listener.accept(); System.out.println("A client-request is accepted."); } } } And I found a behavior that I cannot explain: I start a server, than I start a client. Connection is successfully established (client stops running and server is running). Then I close the server and start it again in a second. After that I start a client and it writes "Connection Refused". It seems to me that the server "remember" the old connection and does not want to open the second connection twice. But I do not understand how it is possible. Because I killed the previous server and started a new one! I do not start the server immediately after the previous one was killed (I wait like 20 seconds). In this case the server "forget" the socket from the previous server and accepts the request from the client. I start the server and then I start the client. Connection is established (server writes: "A client-request is accepted"). Then I wait a minute and start the client again. And server (which was running the whole time) accept the request again! Why? The server should not accept the request from the same client-IP and client-port but it does!

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  • Strange problem publishing a fresh Ruby on Rails 3 application on localhost (Apache, Passenger and VirtualHosts)

    - by user502052
    I recently created a new Ruby on Rails 3 application locally on a Mac OS, named "test". Since I use apache2, in the private/etc/apache2/httpd.conf I set the VirtualHost for the "test" application: <VirtualHost *:443> ServerName test.pjtmain.localhost:443 DocumentRoot "/Users/<my_user_name>/Sites/test/public" RackEnv development <Directory "/Users/<my_user_name>/Sites/test/public"> Order allow,deny Allow from all </Directory> # SSL Configuration SSLEngine on ... </VirtualHost> <VirtualHost *:80> ServerName test.pjtmain.localhost DocumentRoot "/Users/<my_user_name>/Sites/test/public" RackEnv development <Directory "/Users/<my_user_name>/Sites/test/public"> Order allow,deny Allow from all </Directory> </VirtualHost> Of course I restart apache2, but trying to access to http://test.pjtmain.localhost/ I have this error message from: FIREFOX Oops! Firefox could not find test.pjtmain.localhost Suggestions: * Search on Google: ... SAFARI Safari can’t find the server. Safari can’t open the page “http://test.pjtmain.localhost/” because Safari can’t find the server “test.pjtmain.localhost”. I have other RoR3 applications setted like that above in the httpd.conf file and all them work. What is the problem (maybe it is not related to apache...)? Notes: 1. Using the 'Network Uility' I did a Ping with the following result: ping: cannot resolve test.pjtmain.localhost: Unknown host and I did a Lookup with the follonwing result: ; <<>> DiG 9.6.0-APPLE-P2 <<>> test.pjtmain.localhost +multiline +nocomments +nocmd +noquestion +nostats +search ;; global options: +cmd <MY_BROADBAND_TELECOMUNICATIONS_COMPANY_NAME>.com. 115 IN SOA dns1.<MY_BROADBAND_TELECOMUNICATIONS_COMPANY_NAME>.com. dnsmaster.<MY_BROADBAND_TELECOMUNICATIONS_COMPANY_NAME>.com. ( 2010110500 ; serial 10800 ; refresh (3 hours) 900 ; retry (15 minutes) 604800 ; expire (1 week) 86400 ; minimum (1 day) ) 2. I am using Phusion Passenger 3. Since I not changed nothing to the new "test" application, I expect to see the default RoR index.html page: 4. It seems that in the 'Console Messages' there is any warning or error

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  • Is this a valid pattern for raising events in C#?

    - by Will Vousden
    Update: For the benefit of anyone reading this, since .NET 4, the lock is unnecessary due to changes in synchronization of auto-generated events, so I just use this now: public static void Raise<T>(this EventHandler<T> handler, object sender, T e) where T : EventArgs { if (handler != null) { handlerCopy(sender, e); } } And to raise it: SomeEvent.Raise(this, new FooEventArgs()); Having been reading one of Jon Skeet's articles on multithreading, I've tried to encapsulate the approach he advocates to raising an event in an extension method like so (with a similar generic version): public static void Raise(this EventHandler handler, object @lock, object sender, EventArgs e) { EventHandler handlerCopy; lock (@lock) { handlerCopy = handler; } if (handlerCopy != null) { handlerCopy(sender, e); } } This can then be called like so: protected virtual void OnSomeEvent(EventArgs e) { this.someEvent.Raise(this.eventLock, this, e); } Are there any problems with doing this? Also, I'm a little confused about the necessity of the lock in the first place. As I understand it, the delegate is copied in the example in the article to avoid the possibility of it changing (and becoming null) between the null check and the delegate call. However, I was under the impression that access/assignment of this kind is atomic, so why is the lock necessary? Update: With regards to Mark Simpson's comment below, I threw together a test: static class Program { private static Action foo; private static Action bar; private static Action test; static void Main(string[] args) { foo = () => Console.WriteLine("Foo"); bar = () => Console.WriteLine("Bar"); test += foo; test += bar; test.Test(); Console.ReadKey(true); } public static void Test(this Action action) { action(); test -= foo; Console.WriteLine(); action(); } } This outputs: Foo Bar Foo Bar This illustrates that the delegate parameter to the method (action) does not mirror the argument that was passed into it (test), which is kind of expected, I guess. My question is will this affect the validity of the lock in the context of my Raise extension method? Update: Here is the code I'm now using. It's not quite as elegant as I'd have liked, but it seems to work: public static void Raise<T>(this object sender, ref EventHandler<T> handler, object eventLock, T e) where T : EventArgs { EventHandler<T> copy; lock (eventLock) { copy = handler; } if (copy != null) { copy(sender, e); } }

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  • Is there a way to make a serialized member to serialize as an attribute?

    - by Shimmy
    Is there a way to make a serialized member to serialize as an attribute: <Serializable> Public Class Person Public Property Name As String End Class I want than when this class is xml-serialized, it should produce: <Person Name="John Doe" /> And what I mean is that instead of the Name property should be serialized as an element, it should be serialized as an xml attribute.

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  • Error with my Android Application httpGet

    - by Coombes
    Basically I'm getting a strange issue with my Android application, it's supposed to grab a JSON Array and print out some values, the class looks like this: ShowComedianActivity.class package com.example.connecttest; public class ShowComedianActivity extends Activity{ TextView name; TextView add; TextView email; TextView tel; String id; // Progress Dialog private ProgressDialog pDialog; //JSON Parser class JSONParser jsonParser = new JSONParser(); // Single Comedian url private static final String url_comedian_details = "http://86.9.71.17/connect/get_comedian_details.php"; // JSON Node names private static final String TAG_SUCCESS = "success"; private static final String TAG_COMEDIAN = "comedian"; private static final String TAG_ID = "id"; private static final String TAG_NAME = "name"; private static final String TAG_ADDRESS = "address"; private static final String TAG_EMAIL = "email"; private static final String TAG_TEL = "tel"; public void onCreate(Bundle savedInstanceState){ super.onCreate(savedInstanceState); setContentView(R.layout.show_comedian); // Getting Comedian Details from intent Intent i = getIntent(); // Getting id from intent id = i.getStringExtra(TAG_ID); new GetComedianDetails().execute(); } class GetComedianDetails extends AsyncTask<String, String, String>{ protected void onPreExecute(){ super.onPreExecute(); pDialog = new ProgressDialog(ShowComedianActivity.this); pDialog.setMessage("Fetching Comedian details. Please wait..."); pDialog.setIndeterminate(false); pDialog.setCancelable(true); pDialog.show(); } @Override protected String doInBackground(String... params) { runOnUiThread(new Runnable(){ public void run(){ int success; try{ //Building parameters List<NameValuePair> params = new ArrayList<NameValuePair>(); params.add(new BasicNameValuePair("id",id)); // Getting comedian details via HTTP request // Uses a GET request JSONObject json = jsonParser.makeHttpRequest(url_comedian_details, "GET", params); // Check Log for json response Log.d("Single Comedian details", json.toString()); //JSON Success tag success = json.getInt(TAG_SUCCESS); if(success == 1){ // Succesfully received product details JSONArray comedianObj = json.getJSONArray(TAG_COMEDIAN); //JSON Array // get first comedian object from JSON Array JSONObject comedian = comedianObj.getJSONObject(0); // comedian with id found name = (TextView) findViewById(R.id.name); add = (TextView) findViewById(R.id.add); email = (TextView) findViewById(R.id.email); tel = (TextView) findViewById(R.id.tel); // Set text to details name.setText(comedian.getString(TAG_NAME)); add.setText(comedian.getString(TAG_ADDRESS)); email.setText(comedian.getString(TAG_EMAIL)); tel.setText(comedian.getString(TAG_TEL)); } } catch (JSONException e){ e.printStackTrace(); } } }); return null; } } } And my JSON Parser class looks like: package com.example.connecttest; public class JSONParser { static InputStream is = null; static JSONObject jObj = null; static String json = ""; // constructor public JSONParser() { } // function get json from url // by making HTTP POST or GET method public JSONObject makeHttpRequest(String url, String method, List<NameValuePair> params) { // Making HTTP request try { // check for request method if(method == "POST"){ // request method is POST // defaultHttpClient DefaultHttpClient httpClient = new DefaultHttpClient(); HttpPost httpPost = new HttpPost(url); httpPost.setEntity(new UrlEncodedFormEntity(params)); HttpResponse httpResponse = httpClient.execute(httpPost); HttpEntity httpEntity = httpResponse.getEntity(); is = httpEntity.getContent(); }else if(method == "GET"){ // request method is GET DefaultHttpClient httpClient = new DefaultHttpClient(); String paramString = URLEncodedUtils.format(params, "utf-8"); url += "?" + paramString; HttpGet httpGet = new HttpGet(url); HttpResponse httpResponse = httpClient.execute(httpGet); HttpEntity httpEntity = httpResponse.getEntity(); is = httpEntity.getContent(); } } catch (UnsupportedEncodingException e) { e.printStackTrace(); } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } try { BufferedReader reader = new BufferedReader(new InputStreamReader( is, "iso-8859-1"), 8); StringBuilder sb = new StringBuilder(); String line = null; while ((line = reader.readLine()) != null) { sb.append(line + "\n"); } is.close(); json = sb.toString(); } catch (Exception e) { Log.e("Buffer Error", "Error converting result " + e.toString()); } // try parse the string to a JSON object try { jObj = new JSONObject(json); } catch (JSONException e) { Log.e("JSON Parser", "Error parsing data " + e.toString()); } // return JSON String return jObj; } } Now when I run a debug it's querying the correct address with ?id=1 on the end of the URL, and when I navigate to that url I get the following JSON Array: {"success":1,"comedian":[{"id":"1","name":"Michael Coombes","address":"5 Trevethenick Road","email":"[email protected]","tel":"xxxxxxxxxxxx"}]} However my app just crashes, the log-cat report looks like this: 03-22 02:05:02.140: E/Trace(3776): error opening trace file: No such file or directory (2) 03-22 02:05:04.590: E/AndroidRuntime(3776): FATAL EXCEPTION: main 03-22 02:05:04.590: E/AndroidRuntime(3776): android.os.NetworkOnMainThreadException 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117) 03-22 02:05:04.590: E/AndroidRuntime(3776): at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84) 03-22 02:05:04.590: E/AndroidRuntime(3776): at libcore.io.IoBridge.connectErrno(IoBridge.java:127) 03-22 02:05:04.590: E/AndroidRuntime(3776): at libcore.io.IoBridge.connect(IoBridge.java:112) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.net.Socket.connect(Socket.java:842) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:144) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487) 03-22 02:05:04.590: E/AndroidRuntime(3776): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465) 03-22 02:05:04.590: E/AndroidRuntime(3776): at com.example.connecttest.JSONParser.makeHttpRequest(JSONParser.java:62) 03-22 02:05:04.590: E/AndroidRuntime(3776): at com.example.connecttest.ShowComedianActivity$GetComedianDetails$1.run(ShowComedianActivity.java:89) 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.os.Handler.handleCallback(Handler.java:615) 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.os.Handler.dispatchMessage(Handler.java:92) 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.os.Looper.loop(Looper.java:137) 03-22 02:05:04.590: E/AndroidRuntime(3776): at android.app.ActivityThread.main(ActivityThread.java:4745) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.lang.reflect.Method.invokeNative(Native Method) 03-22 02:05:04.590: E/AndroidRuntime(3776): at java.lang.reflect.Method.invoke(Method.java:511) 03-22 02:05:04.590: E/AndroidRuntime(3776): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 03-22 02:05:04.590: E/AndroidRuntime(3776): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 03-22 02:05:04.590: E/AndroidRuntime(3776): at dalvik.system.NativeStart.main(Native Method) From this I'm guessing the error is in the jsonParser.makeHttpRequest however I can't for the life of me figure out what's going wrong and was hoping someone brighter than I could illuminate me.

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  • Pop-Up Window at inital start up, of android application

    - by Josh Fairbank
    I am trying to find a code that will do a popup at the initial start up on an installed app. Much like a changelog that is starting to appear in more and more apps. I have found some similar codes, but being a beginner I haven't been able to figure out where to exactly put the code in and I always have tons of errors that still do not work once I try and fix them. I am working in Eclipse with an android project, and I'm using a webview to show a website. XML: <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <WebView xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/webview" android:layout_height="fill_parent" android:layout_width="fill_parent" android:scrollbarAlwaysDrawVerticalTrack="false"/> </LinearLayout> Java File: package com.A2Ddesigners.WhatThe; import android.app.Activity; import android.os.Bundle; import android.webkit.WebView; import android.webkit.WebViewClient; import android.view.KeyEvent; public class Whatthe extends Activity { WebView webview; /** Called when the activity is first created. */ @Override public boolean onKeyDown(int keyCode, KeyEvent event) { if ((keyCode == KeyEvent.KEYCODE_BACK) && webview.canGoBack()) { webview.goBack(); return true; } return super.onKeyDown(keyCode, event); } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); webview = (WebView) findViewById(R.id.webview); webview.setWebViewClient(new HelloWebViewClient()); webview.getSettings().setJavaScriptEnabled(true); webview.setInitialScale(50); webview.getSettings().setUseWideViewPort(true); webview.loadUrl("http://mdsitest2.com/"); } private class HelloWebViewClient extends WebViewClient { @Override public boolean shouldOverrideUrlLoading(WebView view, String url) { view.loadUrl(url); return true; } } }

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  • Trying to add functionality to MvcHandler

    - by Alexandre Brisebois
    I am currently trying to add 301 redirect to my routes in MVC to do this I have tried to inherit from the MvcHandler. The handler gets instantited with the right values. but I am never able to debug the overridden methods. can someone show me a working attempt at this? the asp.net pipe simply seems to the doing its own thing... public class CodeHttpHandler : MvcHandler { public CodeHttpHandler(RequestContext p_requestContext) : base(p_requestContext) { } protected override void ProcessRequest(HttpContext p_httpContext) { } protected override void ProcessRequest(HttpContextBase p_httpContext) { } }

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  • Wcf inhereted models

    - by jack london
    [DataContract] Base { [DataMember] public int Id {get;set;} } [DataContract] A : Base { [DataMember] public string Value {get;set;} } [ServiceContract] interface IService { [OperationContract] void SetValue (Base base); } is there a way to use the service like the following style: new Service ().SetValue (new A ());

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