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  • Weird compile-time behavior when trying to use primitive type in generics

    - by polygenelubricants
    import java.lang.reflect.Array; public class PrimitiveArrayGeneric { static <T> T[] genericArrayNewInstance(Class<T> componentType) { return (T[]) Array.newInstance(componentType, 0); } public static void main(String args[]) { int[] intArray; Integer[] integerArray; intArray = (int[]) Array.newInstance(int.class, 0); // Okay! integerArray = genericArrayNewInstance(Integer.class); // Okay! intArray = genericArrayNewInstance(int.class); // Compile time error: // cannot convert from Integer[] to int[] integerArray = genericArrayNewInstance(int.class); // Run time error: // ClassCastException: [I cannot be cast to [Ljava.lang.Object; } } I'm trying to fully understand how generics works in Java. Things get a bit weird for me in the 3rd assignment in the above snippet: the compiler is complaining that Integer[] cannot be converted to int[]. The statement is 100% true, of course, but I'm wondering WHY the compiler is making this complaint. If you comment that line, and follow the compiler's "suggestion" as in the 4th assignment, the compiler is actually satisfied!!! NOW the code compiles just fine! Which is crazy, of course, since like the run time behavior suggests, int[] cannot be converted to Object[] (which is what T[] is type-erased into at run time). So my question is: why is the compiler "suggesting" that I assign to Integer[] instead for the 3rd assignment? How does the compiler reason to arrive to that (erroneous!) conclusion?

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  • "Exception in thread "main" java.lang.NoSuchMethodError Do i miss library in the installed JDk?

    - by Ahmad
    Hello every body I was using the JDK very well writing the code then i use "javac" to compile it then "java" to run it But Recently when i write a code and compile it then if i try to run it this exception appears to me "Exception in thread "main" java.lang.NoSuchMethodError " at first i thought there is something wrong in my code , i searched in the internet for a solving for this problem but i didn't find anything may help me Then i try to run the "HelloWorld" example i made it before, it runs i copied the code and pasted it in another file and changed the name to "HelloWorld2" and compile it by "javac" and tried to run it by "java" the same exception appears i was surprised why? it is the same code then i used the "javap" which decompile the code with both i found this difference in the first one (the old one) "public static void main(java.lang.String[])"; but in the second (the new one) "public static void main(String[])"; without java.lang then i compiled the old one which works and runs by "javac" and when i try to run it, it didn't run and give me the same exception i tried with some of my old codes it run and when i compile it by "javac" it doesn't work I searched to find a solution to this problem and i found nothing

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  • Why does my TextBox with custom control template not have a visible text cursor?

    - by Philipp Schmid
    I have a custom control template which is set via the style property on a TextBox. The visual poperties are set correctly, even typing to the textbox works, but there is no insertion cursor (the | symbol) visible which makes editing challenging for our users. How does the control template need changing to get the traditional TextBox behavior back? <Style x:Key="DemandEditStyle" TargetType="TextBox"> <EventSetter Event="LostFocus" Handler="DemandLostFocus" /> <Setter Property="HorizontalAlignment" Value="Stretch" /> <Setter Property="VerticalAlignment" Value="Stretch" /> <Setter Property="Template"> <Setter.Value> <ControlTemplate> <Grid HorizontalAlignment="Stretch" VerticalAlignment="Stretch"> <Grid.ColumnDefinitions> <ColumnDefinition Width="*" /> <ColumnDefinition Width="1" /> </Grid.ColumnDefinitions> <Grid.RowDefinitions> <RowDefinition Height="*" /> <RowDefinition Height="1" /> </Grid.RowDefinitions> <Grid.Background> <LinearGradientBrush StartPoint="0,0" EndPoint="0,1"> <GradientStop Color="White" Offset="0" /> <GradientStop Color="White" Offset="0.15" /> <GradientStop Color="#EEE" Offset="1" /> </LinearGradientBrush> </Grid.Background> <Border Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="2" Background="Black" /> <Border Grid.Row="0" Grid.Column="1" Grid.RowSpan="2" Background="Black" /> <Grid Grid.Row="0" Grid.Column="0" Margin="2"> <Grid.ColumnDefinitions> <ColumnDefinition Width="1" /> <ColumnDefinition Width="*" /> <ColumnDefinition Width="1" /> </Grid.ColumnDefinitions> <Grid.RowDefinitions> <RowDefinition Height="1" /> <RowDefinition Height="*" /> <RowDefinition Height="1" /> </Grid.RowDefinitions> <Border Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="3" Background="Black" /> <Border Grid.Row="0" Grid.Column="0" Grid.RowSpan="3" Background="Black" /> <Border Grid.Row="2" Grid.Column="0" Grid.ColumnSpan="3" Background="#CCC" /> <Border Grid.Row="0" Grid.Column="2" Grid.RowSpan="3" Background="#CCC" /> <TextBlock Grid.Row="1" Grid.Column="1" TextAlignment="Right" HorizontalAlignment="Center" VerticalAlignment="Center" Padding="3 0 3 0" Background="Yellow" Text="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Text}" Width="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Grid}, AncestorLevel=1}, Path=ActualWidth}" /> </Grid> </Grid> </ControlTemplate> </Setter.Value> </Setter> </Style> Update: Replacing the inner-most TextBox with a ScrollViewer and naming it PART_ContentHost indeed shows the text insertion cursor. Trying to right-align the text in the TextBox by either setting the HorizontalContentAlignment in the Style or as a property on the ScrollViewer were unsuccessful. Suggestions?

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  • Send Click Message to another application process

    - by Nazar Hussain
    I have a scenario, i need to send click events to an independent application. I started that application with the following code. private Process app; app = new Process(); app.StartInfo.FileName = app_path; app.StartInfo.WorkingDirectory = dir_path; app.Start(); Now i want to send Mouse click message to that applicaiton, I have specific coordinates in relative to application window. How can i do it using Windows Messaging or any other technique. I used [DllImport("user32.dll")] private static extern void mouse_event(UInt32 dwFlags, UInt32 dx, UInt32 dy, UInt32 dwData, IntPtr dwExtraInfo); It works well but cause the pointer to move as well. So not fit for my need. Then i use. [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)] static extern IntPtr SendMessage(IntPtr hWnd, int Msg, int wParam, int lParam); It works well for minimize maximize, but do not work for mouse events. The codes for mousevents i am using are, WM_LBUTTONDOWN = 0x201, //Left mousebutton down WM_LBUTTONUP = 0x202, //Left mousebutton up WM_LBUTTONDBLCLK = 0x203, //Left mousebutton doubleclick WM_RBUTTONDOWN = 0x204, //Right mousebutton down WM_RBUTTONUP = 0x205, //Right mousebutton up WM_RBUTTONDBLCLK = 0x206, //Right mousebutton do Thanks for the help in advance, and waiting for feedback.

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  • c# finding matching words in table column using Linq2Sql

    - by David Liddle
    I am trying to use Linq2Sql to return all rows that contain values from a list of strings. The linq2sql class object has a string property that contains words separated by spaces. public class MyObject { public string MyProperty { get; set; } } Example MyProperty values are: MyObject1.MyProperty = "text1 text2 text3 text4" MyObject2.MyProperty = "text2" For example, using a string collection, I pass the below list var list = new List<>() { "text2", "text4" } This would return both items in my example above as they both contain "text2" value. I attempted the following using the below code however, because of my extension method the Linq2Sql cannot be evaluated. public static IQueryable<MyObject> WithProperty(this IQueryable<MyProperty> qry, IList<string> p) { return from t in qry where t.MyProperty.Contains(p, ' ') select t; } I also wrote an extension method public static bool Contains(this string str, IList<string> list, char seperator) { if (String.IsNullOrEmpty(str) || list == null) return false; var splitStr = str.Split(new char[] { seperator }, StringSplitOptions.RemoveEmptyEntries); foreach (string s in splitStr) foreach (string l in list) if (String.Compare(s, l, true) == 0) return true; return false; } Any help or ideas on how I could achieve this?

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  • How can I control UISlider Value Changed-events frequncy?

    - by Albert
    I'm writing an iPhone app that is using two uisliders to control values that are sent using coreBluetooth. If I move the sliders quickly one value freezes at the receiver, presumably because the Value Changed events trigger so often that the write-commands stack up and eventually get thrown away. How can I make sure the events don't trigger too often? Edit: Here is a clarification of the problem; the bluetooth connection sends commands every 105ms. If the user generates a bunch of events during that time they seem to que up. I would like to throw away any values generated between the connection events and just send one every 105ms. This is basically what I'm doing right now: -(IBAction) sliderChanged:(UISlider *)sender{ static int8_t value = 0; int8_t new_value = (int8_t)sender.value; if ( new_value > value + threshold || new_value < value - threshold ) { value = new_value; [btDevice writeValue:value]; } } What I'm asking is how to implement something like -(IBAction) sliderChanged:(UISlider *)sender{ static int8_t value = 0; if (105msHasPassed) { int8_t new_value = (int8_t)sender.value; if ( new_value > value + threshold || new_value < value - threshold ) { value = new_value; [btDevice writeValue:value]; } } }

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  • ASP.NET MVC twitter/myspace style routing

    - by Astrofaes
    Hi guys, This is my first post after being a long-time lurker - so please be gentle :-) I have a website similar to twitter, in that people can sign up and choose a 'friendly url', so on my site they would have something like: mydomain.com/benjones I also have root level static pages such as: mydomain.com/about and of course my homepage: mydomain.com/ I'm new to ASP.NET MVC 2 (in fact I just started today) and I've set up the following routes to try and achieve the above. public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.IgnoreRoute("content/{*pathInfo}"); routes.IgnoreRoute("images/{*pathInfo}"); routes.MapRoute("About", "about", new { controller = "Common", action = "About" } ); // User profile sits at root level so check for this before displaying the homepage routes.MapRoute("UserProfile", "{url}", new { controller = "User", action = "Profile", url = "" } ); routes.MapRoute("Home", "", new { controller = "Home", action = "Index", id = "" } ); } For the most part this works fine, however, my homepage is not being triggered! Essentially, when you browser to mydomain.com, it seems to trigger the User Profile route with an empty {url} parameter and so the homepage is never reached! Any ideas on how I can show the homepage?

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  • [java] Returning the element number of the longest string in an array

    - by JohnRoberts
    Hoookay, so. I'm trying to get the longestS method to take the user-inputted array of strings, then return the element number of the longest string in that array. I got it to the point where I was able to return the number of chars in the longest string, but I don't believe that will work for what I need. My problem is that I keep getting incompatible type errors when trying to figure this out. I don't understand the whole data type thing with strings yet. It's confusing me how I go about return a number of the array yet the array is of strings. The main method is fine, I got stuck on the ???? part. { public static void main(String [] args) { Scanner inp = new Scanner( System.in ); String [] responseArr= new String[4]; for (int i=0; i<4; i++) { System.out.println("Enter string "+(i+1)); responseArr[i] = inp.nextLine(); } int highest=longestS(responseArr); } public static int longestS(String[] values) { int largest=0 for( int i = 1; i < values.length; i++ ) { if ( ????? ) } return largest; } }

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  • Sharepoint fails to load a C++ dll on windows 2008

    - by Nathan
    I have a sharepoint DLL that does some licensing things and as part of the code it uses an external C++ DLL to get the serial number of the hardisk. When i run this application on windows server 2003 it works fine, but on 2008 the whole site (loaded on load) crashes and resets continually. This is not 2008 R2 and is the same in 64 or 32 bits. If i put a debugger.break before the dll execution then I see the code get to the point of the break then never come back into the dll again. I do get some debug assertion warnings from within the function, again only in 2008, but im not sure this is related. I created a console app that runs the c# dll, which in turn loads the c++ dll, and this works perfectly on 2008 (although does show the assertion errors, but I have suppressed these now). The assertion errors are not in my code but within ICtypes.c and not something I can debug. If i put a breakpoint in the DLL it is never hit and the compiler says : "step in: Stepping over non user code" if i try to debug into the DLL using VS. I have tried wrapping the code used to call the DLL in: SPSecurity.RunWithElevatedPrivileges(delegate() but this also does not help. I have the sourcecode for this DLL so that is not a problem. If i delete the DLL from the directory I get an error about a missing DLL, if i replace it back to no error or warning just a complete failure. If i replace this code with a hardcoded string the whole application works fine. Any advice would be much appreciated, I can't understand why it works as a console app yet not when run by sharepoint, this is with the same user account, on the same machine... This is the code used to call the DLL: [DllImport("idDll.dll", EntryPoint = "GetMachineId", SetLastError = true)] extern static string GetComponentId([MarshalAs(UnmanagedType.LPStr)]String s); public static string GetComponentId() { Debugger.Break(); if (_machine == string.Empty) { string temp = ""; id= ComponentId.GetComponentId(temp); } return id; }

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  • Error while reading custom configuration file(app.config)

    - by Newbie
    I am making a custom configuration in my winform application. (It will represent a country-corrency list) First the CountryList class namespace UtilityMethods { public class CountryList : ConfigurationSection { public CountryList() { // // TODO: Add constructor logic here // } [ConfigurationProperty("CountryCurrency", IsRequired = true)] public Hashtable CountryCurrencies { get { return CountryCurrency.GetCountryCurrency(); } } } } The GetCountryCurrency() method is defined in CountryCurrency class as under namespace UtilityMethods { public static class CountryCurrency { public static Hashtable GetCountryCurrency() { Hashtable ht = new Hashtable(); ht.Add("India", "Rupees"); ht.Add("USA", "Dollar"); return ht; } } } The app.config file looks like <?xml version="1.0" encoding="utf-8" ?> <configuration> <configSections> <section name ="CountryList1" type ="UtilityMethods.CountryList,CountryList,Version=2.0.0.0, Culture=neutral"/> </configSections> <appSettings /> </configuration> And I am calling this from a button_click's event as try { CountryList cList = ConfigurationManager.GetSection("CountryList") as CountryList; Hashtable ht = cList.CountryCurrencies; } catch (Exception ex) { string h = ex.Message; } Upon running the application and clicking on the button I am getting this error Could not load type 'UtilityMethods.CountryList' from assembly 'System.Configuration, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' Please help (dotnet framework : 3.5 Language: C#)

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  • I can not get the text from a selected item in a listview...pleeeeasss help.

    - by Miguel
    I always get an ClassCastException error... i do not what else to do... - I'm using a data biding concept to populated the listview from a sqlite3 database. - I just want to get the selected item text after a long press click. This is the code of the activity: public class ItemConsultaGastos extends ListActivity { private DataHelper dh ; TextView seleccion; private static String[] FROM = {DataHelper.MES, DataHelper.ANO}; private static int[] TO = {R.id.columnaMes, R.id.columnaAno }; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.muestrafechas); this.dh = new DataHelper(this); Cursor cursor = dh.selectAllMeses(); startManagingCursor(cursor); this.mostrarFechas(cursor); ListView lv = getListView(); lv.setOnItemLongClickListener(new OnItemLongClickListener(){ @Override public boolean onItemLongClick(AdapterView<?> arg0, View arg1,int row, long arg3) { //here is where i got the classCastException. String[] tmp = (String[]) arg0.getItemAtPosition(row); //tmp[0] ist the Text of the first TextView displayed by the clicked ListItem Log.w("Gastos: ", "El texto: " + tmp[0].toString()); return true; } }); } private void mostrarFechas(Cursor cursor) { SimpleCursorAdapter adapter = new SimpleCursorAdapter(this,R.layout.muestrafechasitem,cursor, FROM, TO); setListAdapter(adapter); } } ///// This is the xml where a define the rows to show on the listview <TextView android:id="@+id/espacio" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text=" " /> <TextView android:id="@+id/columnaAno" android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="20sp" android:layout_toRightOf="@+id/espacio"/> <TextView android:id="@+id/separador1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text=" -- " android:layout_toRightOf="@+id/columnaAno" android:textSize="20sp" /> <TextView android:id="@+id/columnaMes" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_toRightOf="@+id/separador1" android:textSize="20sp"/>

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  • Problem with generic list and extension method(C#3.0)

    - by Newbie
    I have an issue. I am making an extension class for a Collection and it is generic.. like public static class ListExtensions { public static ICollection<T> Search<T>(this ICollection<T> collection, string stringToSearch) { ICollection<T> t1=null; foreach (T t in collection) { Type k = t.GetType(); PropertyInfo pi = k.GetProperty("Name"); if (pi.GetValue(t,null).Equals(stringToSearch)) { t1.Add(t); } } return t1; } } But I cannot add items to t1 as it is declared null. Error: object reference not set to an instance of the object. I am calling the method like List<TestClass> listTC = new List<TestClass>(); listTC.Add(new TestClass { Name = "Ishu", Age = 21 }); listTC.Add(new TestClass { Name = "Vivek", Age = 40 }); listTC.Add(new TestClass { Name = "some one else", Age = 12 }); listTC.Search("Ishu"); And the test class is public class TestClass { public string Name { get; set; } public int Age { get; set; } } Using : (C#3.0) & Framework - 3.5 Thanks

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  • OOP C# Question: Making a Fruit a Pear

    - by Adam Kane
    Given that I have an instance of Fruit with some properties set, and I want to get those properties into a new Pear instance (because this particular Fruit happens to have the qualities of a pear), what's the best way to achieve this effect? For example, what we can't do is simple cast a Fruit to a Pear, because not all Fruits are Pears: public static class PearGenerator { public static Pear CreatePear () { // Make a new generic fruit. Fruit genericFruit = new Fruit(); // Upcast it to a pear. (Throws exception: Can't cast a Fruit to a Pear.) Pear pear = (Pear)genericFruit; // Return freshly grown pear. return ( pear ); } } public class Fruit { // some code } public class Pear : Fruit { public void PutInPie () { // some code } } Thanks! Update: I don't control the "new Fruit()" code. My starting point is that I've got a Fruit to work with. I need to get that Fruit into a new Pear somehow. Maybe copy all the properties one by one?

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  • IIS7.5 is only resolving to the Default Web Site

    - by Dennis Burnham
    I am able to access only the Default Web Site on a Windows 2008 R2 Server which is running IIS 7.5 The Default Web Site's binding is to "All Unassigned", same way as I have done it on a different machine running IIS6 under Windows 2003 Server. The bindings of the desired Web Site have the IP address of the server and the correct home directory. Regardless what I do, the only page content I can see is the default index page in the wwwroot directory which is the Default Web Site. What must I do to deliver the correct content from the Web Sites that are configured in IIS7.5?

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  • "reset" cells after changing orientation

    - by Christian
    Hi, I added the interfaceOrientation to my app. It works fine concerning the views. Some of the table-cells I defined by CGRects to position the text in the cell. In portrait-mode the cell is 300px long, in landscape-mode 420px. I use the following code to change the CGRects depending the orientation: - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { if (self.interfaceOrientation == UIDeviceOrientationPortrait) { NSString *currentLanguage = [[NSString alloc] initWithContentsOfFile:[NSHomeDirectory() stringByAppendingPathComponent:@"/Documents/sprache.txt"]]; static NSString *TableViewTableCellIdentifier = @"TableViewTableCellIdentifier"; UITableViewCell *cell = (UITableViewCell *) [tableView dequeueReusableCellWithIdentifier:TableViewTableCellIdentifier]; CGRect cellRect = CGRectMake(0, 0, 300, 175); cell.backgroundColor = [UIColor darkGrayColor]; cell = [[[UITableViewCell alloc] initWithFrame:cellRect reuseIdentifier:TableViewTableCellIdentifier] autorelease]; CGRect keyLabelRect = CGRectMake(0, 5, 5, 20); UILabel *keyLabel = [[UILabel alloc]initWithFrame:keyLabelRect]; keyLabel.tag = 100;......... } else { NSString *currentLanguage = [[NSString alloc] initWithContentsOfFile:[NSHomeDirectory() stringByAppendingPathComponent:@"/Documents/sprache.txt"]]; static NSString *TableViewTableCellIdentifier = @"TableViewTableCellIdentifier"; UITableViewCell *cell = (UITableViewCell *) [tableView dequeueReusableCellWithIdentifier:TableViewTableCellIdentifier]; CGRect cellRect = CGRectMake(0, 0, 450, 175); cell.backgroundColor = [UIColor darkGrayColor]; cell = [[[UITableViewCell alloc] initWithFrame:cellRect reuseIdentifier:TableViewTableCellIdentifier] autorelease]; CGRect keyLabelRect = CGRectMake(0, 5, 5, 20); UILabel *keyLabel = [[UILabel alloc]..... My problem is, when the table is visible and the orientation is changed, I need to scroll to see the new "layout". How can I manage to "reload" the view after changing the orientation?

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  • Hibernate Transient Extends problem

    - by mrvreddy
    @MappedSuperclass public abstract class BaseAbstract implements Serializable{ private static final long serialVersionUID = 1L; protected String test = //some random value; public String getTest() { return test; } public void setTest(String test){ this.test = test; } } @Entity public class Artist extends BaseAbstract { private static final long serialVersionUID = 1L; private Integer id; @override @Transient public String getTest() { return test; } ..... } My question is... when i am trying to do any operation on the artist, along with id and name, test is also getting saved which should not be the case... if i add the same transient on the baseabstract class getTest() method, i see test column NOT getting created(ideally what it should happen) but if i try to override the method with adding annotaion in the sub class it creates the test column... I dont know why this is happening since when hibernate is creating the artist object and checks for annotations, it should see the transient annotation present on the getTest() of artist method...and should not create a column in the database... Let me know if you need any clarification.... Any response on this is greatly appreciated.... Thank you

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  • How to allow all except part 1 and part 2 ?

    - by Stackfan
    This allows me to get easyly dynamic input variables instead of putting a static prefix like /en/etcetcetc, but the problem is all controllers are blocked. Everything goes to index/index. Question: How can i tell this rule allow evertying as it is now, but do not track if it contains http://site.com/donotcatch/me and http://site.com/iamnotbelongstodynamic1/blabla protected function _initRoutes() { ... $dynamic1 = new Zend_Controller_Router_Route( '/:variable0/:variable1', array( 'controller' => 'index', 'action' => 'index'), array( 'variable0' => '^[a-zA-Z0-9_]*$', 'variable1' => '^[a-zA-Z0-9_]*$', ) ); Follow up: Normally, i always belive yes we can, so, we can do that like this where dynamic1 does not the inter-fare with my other static controllers: // http://site/yeswecan/blabla // variable0 = yeswecan // variable1 = blabla $dynamic1 = new Zend_Controller_Router_Route( '/:variable0/:variable1', array( 'controller' => 'index', 'action' => 'index'), array( 'variable0' => '^[a-zA-Z]*$', 'variable1' => '^[a-z0-9_]*$', ) ); // http://site/ajax/whatever... // solves it $dynamic2 = new Zend_Controller_Router_Route( '/ajax/:variable0', array( 'controller' => 'ajax', 'action' => '' ), array( 'variable0' => '^[a-zA-Z0-9_]*$', ) ); // http://site/order/whatever... // solves it $dynamic3 = new Zend_Controller_Router_Route( '/order/:variable0', array( 'controller' => 'order', 'action' => ''), array( 'variable0' => '^[a-zA-Z0-9_]*$', ) ); Note: Still the controllers are getting failed for example http://site/ajax/whatever always goes to /ajax/index where i wanted to send it as /ajax/user-inserted-value How can i fix the $dynamic2 and $dynamic3 by keeping $dynamic1 ??

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  • Concurrency problem with arrays (Java)

    - by Johannes
    For an algorithm I'm working on I tried to develop a blacklisting mechanism that can blacklist arrays in a specific way: If "1, 2, 3" is blacklisted "1, 2, 3, 4, 5" is also considered blacklisted. I'm quite happy with the solution I've come up with so far. But there seem to be some serious problems when I access a blacklist from multiple threads. The method "contains" (see code below) sometimes returns true, even if an array is not blacklisted. This problem does not occur if I only use one thread, so it most likely is a concurrency problem. I've tried adding some synchronization, but it didn't change anything. I also tried some slightly different implementations using java.util.concurrent classes. Any ideas on how to fix this? public class Blacklist { private static final int ARRAY_GROWTH = 10; private final Node root = new Node(); private static class Node{ private volatile Node[] childNodes = new Node[ARRAY_GROWTH]; private volatile boolean blacklisted = false; public void blacklist(){ this.blacklisted = true; this.childNodes = null; } } public void add(final int[] array){ synchronized (root) { Node currentNode = this.root; for(final int edge : array){ if(currentNode.blacklisted) return; else if(currentNode.childNodes.length <= edge) { currentNode.childNodes = Arrays.copyOf(currentNode.childNodes, edge + ARRAY_GROWTH); } if(currentNode.childNodes[edge] == null) { currentNode.childNodes[edge] = new Node(); } currentNode = currentNode.childNodes[edge]; } currentNode.blacklist(); } } public boolean contains(final int[] array){ synchronized (root) { Node currentNode = this.root; for(final int edge : array){ if(currentNode.blacklisted) return true; else if(currentNode.childNodes.length <= edge || currentNode.childNodes[edge] == null) return false; currentNode = currentNode.childNodes[edge]; } return currentNode.blacklisted; } } }

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  • C++ socket protocol design issue (ring inclusion)

    - by Martin Lauridsen
    So I have these two classes, mpqs_client and client_protocol. The mpqs_client class handles a Boost socket connection to a server (sending and receiving messages with some specific format. Upon receiving a message, it calls a static method, parse_message(..), in the class client_protocol, and this method should analyse the message received and perform some corresponding action. Given some specific input, the parse_message method needs to send some data back to the server. As mentioned, this happens through the class mpqs_client. So I could, from mpqs_client, pass "this" to parse_message(..) in client_protocol. However, this leads to a two-way association relationship between the two classes. Something which I reckon is not desireable. Also, to implement this, I would need to include the other in each one, and this gives me a terrible pain. I am thinking this is more of a design issue. What is the best solution here? Code is posted below. Class mpqs_client: #include "mpqs_client.h" mpqs_client::mpqs_client(boost::asio::io_service& io_service, tcp::resolver::iterator endpoint_iterator) : io_service_(io_service), socket_(io_service) { ... } ... void mpqs_client::write(const network_message& msg) { io_service_.post(boost::bind(&mpqs_client::do_write, this, msg)); } Class client_protocol: #include "../network_message.hpp" #include "../protocol_consts.h" class client_protocol { public: static void parse_message(network_message& msg, mpqs_sieve **instance_, mpqs_client &client_) { ... switch (type) { case MPQS_DATA: ... break; case POLYNOMIAL_DATA: ... break; default: break; } }

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  • Converting application to MVC architecture

    - by terence6
    I'm practicing writing MVC applications. I have a Mastermind game, that I would like to rewrite as MVC app. I have divided my code to parts, but instead of working game I'm getting empty Frame and an error in "public void paint( Graphics g )". Error comes from calling this method in my view with null argument. But how to overcome this ? MVC was quite simple with swing but awt and it's paint methods are much more complicated. Code of working app : http://paste.pocoo.org/show/224982/ App divided to MVC : Main : public class Main { public static void main(String[] args){ Model model = new Model(); View view = new View("Mastermind", 400, 590, model); Controller controller = new Controller(model, view); view.setVisible(true); } } Controller : import java.awt.*; import java.awt.event.*; public class Controller implements MouseListener, ActionListener { private Model model; private View view; public Controller(Model m, View v){ model = m; view = v; view.addWindowListener( new WindowAdapter(){ public void windowClosing(WindowEvent e){ System.exit(0); } }); view.addMouseListener(this); } public void actionPerformed( ActionEvent e ) { if(e.getSource() == view.checkAnswer){ if(model.isRowFull){ model.check(); } } } public void mousePressed(MouseEvent e) { Point mouse = new Point(); mouse = e.getPoint(); if (model.isPlaying){ if (mouse.x > 350) { int button = 1 + (int)((mouse.y - 32) / 50); if ((button >= 1) && (button <= 5)){ model.fillHole(button); } } } } public void mouseClicked(MouseEvent e) {} public void mouseReleased(MouseEvent e){} public void mouseEntered(MouseEvent e) {} public void mouseExited(MouseEvent e) {} } View : import java.awt.*; import javax.swing.*; import java.awt.event.*; public class View extends Frame implements ActionListener { Model model; JButton checkAnswer; private JPanel button; static final int HIT_X[] = {270,290,310,290,310}, HIT_Y[] = {506,496,496,516,516}; public View(String name, int w, int h, Model m){ model = m; setTitle( name ); setSize( w,h ); setResizable( false ); this.setLayout(new BorderLayout()); button = new JPanel(); button.setSize( new Dimension(400, 100)); button.setVisible(true); checkAnswer = new JButton("Check"); checkAnswer.addActionListener(this); checkAnswer.setSize( new Dimension(200, 30)); button.add( checkAnswer ); this.add( button, BorderLayout.SOUTH); button.setVisible(true); for ( int i=0; i < model.SCORE; i++ ){ for ( int j = 0; j < model.LINE; j++ ){ model.pins[i][j] = new Pin(20,0); model.pins[i][j].setPosition(j*50+30,510-i*50); model.pins[i+model.SCORE][j] = new Pin(8,0); model.pins[i+model.SCORE][j].setPosition(HIT_X[j],HIT_Y[j]-i*50); } } for ( int i=0; i < model.LINE; i++ ){ model.pins[model.OPTIONS][i] = new Pin( 20, i+2 ); model.pins[model.OPTIONS][i].setPosition( 370,i * 50 + 56); } model.combination(); model.paint(null); } public void actionPerformed( ActionEvent e ) { } } Model: import java.awt.*; public class Model extends Frame{ static final int LINE = 5, SCORE = 10, OPTIONS = 20; Pin pins[][] = new Pin[21][LINE]; int combination[] = new int[LINE]; int curPin = 0; int turn = 1; int repaintPin; boolean isUpdate = true, isPlaying = true, isRowFull = false; public Model(){ } void fillHole(int color) { pins[turn-1][curPin].setColor(color+1); repaintPins( turn ); curPin = (curPin+1) % LINE; if (curPin == 0){ isRowFull = true; } } public void paint( Graphics g ) { g.setColor( new Color(238, 238, 238)); g.fillRect( 0,0,400,590); for ( int i=0; i < pins.length; i++ ) { pins[i][0].paint(g); pins[i][1].paint(g); pins[i][2].paint(g); pins[i][3].paint(g); pins[i][4].paint(g); } } public void update( Graphics g ) { if ( isUpdate ) { paint(g); } else { isUpdate = true; pins[repaintPin-1][0].paint(g); pins[repaintPin-1][1].paint(g); pins[repaintPin-1][2].paint(g); pins[repaintPin-1][3].paint(g); pins[repaintPin-1][4].paint(g); } } void repaintPins( int pin ) { repaintPin = pin; isUpdate = false; repaint(); } void check() { int junkPegs[] = new int[LINE], junkCode[] = new int[LINE]; int pegCount = 0, pico = 0; for ( int i = 0; i < LINE; i++ ) { junkPegs[i] = pins[turn-1][i].getColor(); junkCode[i] = combination[i]; } for ( int i = 0; i < LINE; i++ ){ if (junkPegs[i]==junkCode[i]) { pins[turn+SCORE][pegCount].setColor(1); pegCount++; pico++; junkPegs[i] = 98; junkCode[i] = 99; } } for ( int i = 0; i < LINE; i++ ){ for ( int j = 0; j < LINE; j++ ) if (junkPegs[i]==junkCode[j]) { pins[turn+SCORE][pegCount].setColor(2); pegCount++; junkPegs[i] = 98; junkCode[j] = 99; j = LINE; } } repaintPins( turn+SCORE ); if ( pico == LINE ){ isPlaying = false; } else if ( turn >= 10 ){ isPlaying = false; } else{ curPin = 0; isRowFull = false; turn++; } } void combination() { for ( int i = 0; i < LINE; i++ ){ combination[i] = 1 + (int)(Math.random()*5); System.out.print(i+","); } } } class Pin{ private int color, X, Y, radius; private static final Color COLORS[] = { Color.black, Color.white, Color.red, Color.yellow, Color.green, Color.blue, new Color(7, 254, 250)}; public Pin(){ X = 0; Y = 0; radius = 0; color = 0; } public Pin( int r,int c ){ X = 0; Y = 0; radius = r; color = c; } public void paint( Graphics g ){ int x = X-radius; int y = Y-radius; if (color > 0){ g.setColor( COLORS[color]); g.fillOval( x,y,2*radius,2*radius ); } else{ g.setColor( new Color(238, 238, 238) ); g.drawOval( x,y,2*radius-1,2*radius-1 ); } g.setColor( Color.black ); g.drawOval( x,y,2*radius,2*radius ); } public void setPosition( int x,int y ){ this.X = x ; this.Y = y ; } public void setColor( int c ){ color = c; } public int getColor() { return color; } } Any clues on how to overcome this would be great. Have I divided my code improperly ?

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  • Compiler turning a string& into a basic_string<>&

    - by Shtong
    Hello I'm coming back to C++ after long years spent on other technologies and i'm stuck on some weird behavior when calling some methods taking std::string as parameters : An example of call : LocalNodeConfiguration *LocalNodeConfiguration::ReadFromFile(std::string & path) { // ... throw configuration_file_error(string("Configuration file empty"), path); // ... } When I compile I get this (I cropped file names for readability) : /usr/bin/g++ -g -I/home/shtong/Dev/OmegaNoc/build -I/usr/share/include/boost-1.41.0 -o CMakeFiles/OmegaNocInternals.dir/configuration/localNodeConfiguration.cxx.o -c /home/shtong/Dev/OmegaNoc/source/configuration/localNodeConfiguration.cxx .../localNodeConfiguration.cxx: In static member function ‘static OmegaNoc::LocalNodeConfiguration* OmegaNoc::LocalNodeConfiguration::ReadFromFile(std::string&)’: .../localNodeConfiguration.cxx:72: error: no matching function for call to ‘OmegaNoc::configuration_file_error::configuration_file_error(std::string, std::basic_string<char, std::char_traits<char>, std::allocator<char> >&)’ .../configurationManager.hxx:25: note: candidates are: OmegaNoc::configuration_file_error::configuration_file_error(std::string&, std::string&) .../configurationManager.hxx:22: note: OmegaNoc::configuration_file_error::configuration_file_error(const OmegaNoc::configuration_file_error&) So as I understand it, the compiler is considering that my path parameter turned into a basic_string at some point, thus not finding the constructor overload I want to use. But I don't really get why this transformation happened. Some search on the net suggested me to use g++ but I was already using it. So any other advice would be appreciated :) Thanks

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  • How does one force construction of a global object in a statically linked library? [MSVC9]

    - by Peter C O Johansson
    I have a global list of function pointers. This list should be populated at startup. Order is not important and there are no dependencies that would complicate static initialization. To facilitate this, I've written a class that adds a single entry to this list in its constructor, and scatter global instances of this class via a macro where necessary. One of the primary goals of this approach is to remove the need for explicitly referencing every instance of this class externally, instead allowing each file that needs to register something in the list to do it independently. Nice and clean. However, when placing these objects in a static library, the linker discards (or rather never links in) these units because no code in them is explicitly referenced. Explicitly referencing symbols in the compilation units would be counterproductive, directly contradicting one of the main goals of the approach. For the same reason, /INCLUDE is not an acceptable option, and /OPT:NOREF is not actually related to this problem. Metrowerks has a __declspec directive for it, GCC has -force_load, but I cannot find any equivalent for MSVC.

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  • Need help extrapolating Java code

    - by Berlioz
    If anyone familiar with Rebecca Wirfs-Brock, she has a piece of Java code found in her book titled, Object Design: Roles, Responsibilities, and Collaborations. Here is the quote Applying Double Dispatch to a Specific Problem To implement the game Rock, Paper, Scissors we need to write code that determines whether one object “beats” another. The game has nine possible outcomes based on the three kinds of objects. The number of interactions is the cross product of the kinds of objects. Case or switch statements are often governed by the type of data that is being operated on. The object-oriented language equivalent is to base its actions on the class of some other object. In Java, it looks like this Here is the piece of Java code on page 16 ' import java.util.*; import java.lang.*; public class Rock { public static void main(String args[]) { } public static boolean beats(GameObject object) { if (object.getClass.getName().equals("Rock")) { result = false; } else if (object.getClass.getName().equals("Paper")) { result = false; } else if(object.getClass.getName().equals("Scissors")) { result = true; } return result; } }' ===This is not a very good solution. First, the receiver needs to know too much about the argument. Second, there is one of these nested conditional statements in each of the three classes. If new kinds of objects could be added to the game, each of the three classes would have to be modified. Can anyone share with me how to get this "less than optimal" piece of code to work in order to see it 'working'. She proceeds to demonstrate a better way, but I will spare you. Thanks

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  • Creating a C++ DLL and then using it in C#

    - by Major
    Ok I'm trying to make a C++ DLL that I can then call and reference in a c# App. I've already made a simple dll using the numberous guides out there, however when I try to reference it in the C# app I get the error Unable to load DLL 'SDES.dll': The specified module could not be found. The code for the program is as follows (bear with me I'm going to include all the files) //These are the DLL Files. ifndef TestDLL_H define TestDLL_H extern "C" { // Returns a + b __declspec(dllexport) double Add(double a, double b); // Returns a - b __declspec(dllexport) double Subtract(double a, double b); // Returns a * b __declspec(dllexport) double Multiply(double a, double b); // Returns a / b // Throws DivideByZeroException if b is 0 __declspec(dllexport) double Divide(double a, double b); } endif //.cpp include "test.h" include using namespace std; extern double __cdecl Add(double a, double b) { return a + b; } extern double __cdecl Subtract(double a, double b) { return a - b; } extern double __cdecl Multiply(double a, double b) { return a * b; } extern double __cdecl Divide(double a, double b) { if (b == 0) { throw new invalid_argument("b cannot be zero!"); } return a / b; } //C# Program using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Runtime.InteropServices; namespace ConsoleApplication1 { class Program { [DllImport("SDES.dll")] public static extern void SimulateGameDLL(int a, int b); static void Main(string[] args) { SimulateGameDLL(1, 2); //Error here... } } } Anyone have any idea's what I may be missing in my program? Let me know if I missed some code or if you have any questions.

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  • Right-aligning button in a grid with possibly no content - stretch grid to always fill the page

    - by Peter Perhác
    Hello people, I am losing my patience with this. I am working on a Windows Phone 7 application and I can't figure out what layout manager to use to achieve the following: Basically, when I use a Grid as the layout root, I can't make the grid to stretch to the size of the phone application page. When the main content area is full, all is well and the button sits where I want it to sit. However, in case the page content is very short, the grid is only as wide as to accommodate its content and then the button (which I am desperate to keep near the right edge of the screen) moves away from the right edge. If I replace the grid and use a vertically oriented stack panel for the layout root, the button sits where I want it but then the content area is capable of growing beyond the bottom edge. So, when I place a listbox full of items into the main content area, it doesn't adjust its height to be completely in view, but the majority of items in that listbox are just rendered below the bottom edge of the display area. I have tried using a third-party DockPanel layout manager and then docked the button in it's top section and set the button's HorizontalAlignment="Right" but the result was the same as with the grid, it also shrinks in size when there isn't enough content in the content area (or when title is short). How do I do this then? ==EDIT== I tried WPCoder's XAML, only I replaced the dummy text box with what I would have in a real page (stackpanel) and placed a listbox into the ContentPanel grid. I noticed that what I had before and what WPCoder is suggesting is very similar. Here's my current XAML and the page still doesn't grow to fit the width of the page and I get identical results to what I had before: <phone:PhoneApplicationPage x:Name="categoriesPage" x:Class="CatalogueBrowser.CategoriesPage" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:phone="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone" xmlns:shell="clr-namespace:Microsoft.Phone.Shell;assembly=Microsoft.Phone" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" FontFamily="{StaticResource PhoneFontFamilyNormal}" FontSize="{StaticResource PhoneFontSizeNormal}" Foreground="{StaticResource PhoneForegroundBrush}" SupportedOrientations="PortraitOrLandscape" Orientation="Portrait" mc:Ignorable="d" d:DesignWidth="480" d:DesignHeight="768" xmlns:ctrls="clr-namespace:Microsoft.Phone.Controls;assembly=Microsoft.Phone.Controls.Toolkit" shell:SystemTray.IsVisible="True"> <Grid x:Name="LayoutRoot" Background="Transparent"> <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition Height="*"/> </Grid.RowDefinitions> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition Width="*" /> <ColumnDefinition Width="Auto" /> </Grid.ColumnDefinitions> <StackPanel Orientation="Horizontal" VerticalAlignment="Center" > <TextBlock Text="Browsing:" Margin="10,10" Style="{StaticResource PhoneTextTitle3Style}" /> <TextBlock x:Name="ListTitle" Text="{Binding DisplayName}" Margin="0,10" Style="{StaticResource PhoneTextTitle3Style}" /> </StackPanel> <Button Grid.Column="1" x:Name="btnRefineSearch" Content="Refine Search" Style="{StaticResource buttonBarStyle}" FontSize="14" /> </Grid> <Grid x:Name="ContentPanel" Grid.Row="1"> <ListBox x:Name="CategoryList" ItemsSource="{Binding Categories}" Style="{StaticResource CatalogueList}" SelectionChanged="CategoryList_SelectionChanged"/> </Grid> </Grid> </phone:PhoneApplicationPage> This is what the page with the above XAML markup looks like in the emulator:

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