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  • Only error showing is null, rss feed reader not working

    - by Callum
    I have been following a tutorial which is showing me how to create an rssfeed reader, I come to the end of the tutorial; and the feed is not displaying in the listView. So I am looking for errors in logCat, but the only one I can find is one just saying 'null', which is not helpful at all. Can anyone spot a potential problem with the code I have written? Thanks. DirectRSS(main class): package com.example.rssapplication; import java.util.List; import android.app.ListActivity; import android.content.pm.ActivityInfo; import android.os.Bundle; import android.util.Log; import android.widget.ArrayAdapter; import android.widget.ListView; public class DirectRSS extends ListActivity{ @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.directrss); //Set to portrait, so that every time the view changes; it does not run the DB query again... setRequestedOrientation (ActivityInfo.SCREEN_ORIENTATION_PORTRAIT); try{ RssReader1 rssReader = new RssReader1("http://www.skysports.com/rss/0,20514,11661,00.xml"); ListView list = (ListView)findViewById(R.id.list); ArrayAdapter<RssItem1> adapter = new ArrayAdapter<RssItem1>(this, android.R.layout.simple_list_item_1); list.setAdapter(adapter); list.setOnItemClickListener(new ListListener1(rssReader.getItems(),this)); }catch(Exception e) { String err = (e.getMessage()==null)?"SD Card failed": e.getMessage(); Log.e("sdcard-err2:",err + " " + e.getMessage()); // Log.e("Error", e.getMessage()); Log.e("LOGCAT", "" + e.getMessage()); } } } ListListener1: package com.example.rssapplication; import java.util.List; import android.app.Activity; import android.content.Intent; import android.net.Uri; import android.view.View; import android.widget.AdapterView; import android.widget.AdapterView.OnItemClickListener; public class ListListener1 implements OnItemClickListener{ List<RssItem1> listItems; Activity activity; public ListListener1(List<RssItem1> listItems, Activity activity) { this.listItems = listItems; this.activity = activity; } @Override public void onItemClick(AdapterView<?> parent, View view, int pos, long id) { // TODO Auto-generated method stub Intent i = new Intent(Intent.ACTION_VIEW); i.setData(Uri.parse(listItems.get(pos).getLink())); activity.startActivity(i); } } RssItem1: package com.example.rssapplication; public class RssItem1 { private String title; private String link; public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public String getLink() { return link; } public void setLink(String link) { this.link = link; } } RssParseHandler1: package com.example.rssapplication; import java.util.ArrayList; import java.util.List; import org.xml.sax.Attributes; import org.xml.sax.SAXException; import org.xml.sax.helpers.DefaultHandler; public class RssParseHandler1 extends DefaultHandler{ private List<RssItem1> rssItems; private RssItem1 currentItem; private boolean parsingTitle; private boolean parsingLink; public RssParseHandler1(){ rssItems = new ArrayList<RssItem1>(); } public List<RssItem1> getItems(){ return rssItems; } @Override public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException { if("item".equals(qName)){ currentItem = new RssItem1(); } else if("title".equals(qName)){ parsingTitle = true; } else if("link".equals(qName)){ parsingLink = true; } // TODO Auto-generated method stub super.startElement(uri, localName, qName, attributes); } @Override public void endElement(String uri, String localName, String qName) throws SAXException { if("item".equals(qName)){ rssItems.add(currentItem); currentItem = null; } else if("title".equals(qName)){ parsingTitle = false; } else if("link".equals(qName)){ parsingLink = false; } // TODO Auto-generated method stub super.endElement(uri, localName, qName); } @Override public void characters(char[] ch, int start, int length) throws SAXException { if(parsingTitle) { if(currentItem!=null) { currentItem.setTitle(new String(ch,start,length)); } } else if(parsingLink) { if(currentItem!=null) { currentItem.setLink(new String(ch,start,length)); parsingLink = false; } } // TODO Auto-generated method stub super.characters(ch, start, length); } } RssReader1: package com.example.rssapplication; import java.util.List; import javax.xml.parsers.SAXParser; import javax.xml.parsers.SAXParserFactory; public class RssReader1 { private String rssUrl; public RssReader1(String rssUrl) { this.rssUrl = rssUrl; } public List<RssItem1> getItems() throws Exception { SAXParserFactory factory = SAXParserFactory.newInstance(); SAXParser saxParser = factory.newSAXParser(); RssParseHandler1 handler = new RssParseHandler1(); saxParser.parse(rssUrl, handler); return handler.getItems(); } } Here is the logCat also: 08-25 11:13:20.803: D/AbsListView(26291): unregisterIRListener() is called 08-25 11:13:20.803: D/AbsListView(26291): unregisterIRListener() is called 08-25 11:13:20.803: D/AbsListView(26291): unregisterIRListener() is called 08-25 11:13:20.813: D/AbsListView(26291): unregisterIRListener() is called 08-25 11:13:20.813: D/AbsListView(26291): unregisterIRListener() is called 08-25 11:13:20.813: D/AbsListView(26291): unregisterIRListener() is called 08-25 11:13:20.813: W/ApplicationPackageManager(26291): getCSCPackageItemText() 08-25 11:13:20.843: D/AbsListView(26291): Get MotionRecognitionManager 08-25 11:13:20.843: E/sdcard-err2:(26291): SD Card failed null 08-25 11:13:20.843: E/LOGCAT(26291): null 08-25 11:13:20.843: D/AbsListView(26291): onVisibilityChanged() is called, visibility : 4 08-25 11:13:20.843: D/AbsListView(26291): unregisterIRListener() is called 08-25 11:13:20.873: D/AbsListView(26291): onVisibilityChanged() is called, visibility : 0 08-25 11:13:20.883: D/AbsListView(26291): unregisterIRListener() is called 08-25 11:13:20.903: D/AbsListView(26291): unregisterIRListener() is called 08-25 11:13:20.933: D/AbsListView(26291): unregisterIRListener() is called 08-25 11:13:20.963: D/AbsListView(26291): unregisterIRListener() is called 08-25 11:13:20.973: D/AbsListView(26291): unregisterIRListener() is called 08-25 11:13:21.323: D/AbsListView(26291): onVisibilityChanged() is called, visibility : 4 08-25 11:13:21.323: D/AbsListView(26291): unregisterIRListener() is called 08-25 11:13:21.323: D/AbsListView(26291): onVisibilityChanged() is called, visibility : 4 08-25 11:13:21.323: D/AbsListView(26291): unregisterIRListener() is called 08-25 11:13:21.323: D/AbsListView(26291): onVisibilityChanged() is called, visibility : 4 08-25 11:13:21.323: D/AbsListView(26291): unregisterIRListener() is called 08-25 11:13:21.323: D/AbsListView(26291): onVisibilityChanged() is called, visibility : 4 08-25 11:13:21.323: D/AbsListView(26291): unregisterIRListener() is called 08-25 11:13:21.323: D/AbsListView(26291): onVisibilityChanged() is called, visibility : 4 08-25 11:13:21.323: D/AbsListView(26291): unregisterIRListener() is called 08-25 11:13:21.333: D/AbsListView(26291): onVisibilityChanged() is called, visibility : 4 08-25 11:13:21.333: D/AbsListView(26291): unregisterIRListener() is called

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  • Castle, sharing a transient component between a decorator and a decorated component

    - by Marius
    Consider the following example: public interface ITask { void Execute(); } public class LoggingTaskRunner : ITask { private readonly ITask _taskToDecorate; private readonly MessageBuffer _messageBuffer; public LoggingTaskRunner(ITask taskToDecorate, MessageBuffer messageBuffer) { _taskToDecorate = taskToDecorate; _messageBuffer = messageBuffer; } public void Execute() { _taskToDecorate.Execute(); Log(_messageBuffer); } private void Log(MessageBuffer messageBuffer) {} } public class TaskRunner : ITask { public TaskRunner(MessageBuffer messageBuffer) { } public void Execute() { } } public class MessageBuffer { } public class Configuration { public void Configure() { IWindsorContainer container = null; container.Register( Component.For<MessageBuffer>() .LifeStyle.Transient); container.Register( Component.For<ITask>() .ImplementedBy<LoggingTaskRunner>() .ServiceOverrides(ServiceOverride.ForKey("taskToDecorate").Eq("task.to.decorate"))); container.Register( Component.For<ITask>() .ImplementedBy<TaskRunner>() .Named("task.to.decorate")); } } How can I make Windsor instantiate the "shared" transient component so that both "Decorator" and "Decorated" gets the same instance? Edit: since the design is being critiqued I am posting something closer to what is being done in the app. Maybe someone can suggest a better solution (if sharing the transient resource between a logger and the true task is considered a bad design)

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  • How can I check if a value exists in a list using C#

    - by Samantha J
    I have the following code that gives me a list of id and names from the new ASP.NET MVC5 Identity: var identityStore = new IdentityStore(); var users = ( from user in identityStore.DbContext.Set<User>() select new { id = user.Id, name = user.UserName } ); How could I modify this so that it allows me to check if a UserName exists? Here's the user class: public class User : IUser { public User(); public User(string userName); [Key] public string Id { get; set; } public virtual ICollection<UserLogin> Logins { get; set; } public virtual UserManagement Management { get; set; } public virtual ICollection<UserRole> Roles { get; set; } public string UserName { get; set; } }

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  • JAVA Inheritance Generics and Casting.

    - by James Moore
    Hello, I have two classes which both extends Example. public class ClassA extends Example { public ClassA() { super("a", "class"); } .... } public class ClassB extends Example { public ClassB() { super("b", "class"); } .... } public class Example () { public String get(String x, String y) { return "Hello"; } } So thats all very well. So suppose we have another class called ExampleManager. With example manager I want to use a generic type and consequently return that generic type. e.g. public class ExampleManager<T extends Example> { public T getExample() { return new T("example","example"); // So what exactly goes here? } } So where I am returning my generic type how do i get this to actually work correctly and cast Example as either classA or classB? Many Thanks

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  • c++ to vb.net , problem with callback function

    - by johan
    I'm having a hard time here trying to find a solution for my problem. I'm trying to convert a client API funktion from C++ to VB.NET, and i think have some problems with the callback function. parts of the C++ code: typedef struct{ BYTE m_bRemoteChannel; BYTE m_bSendMode; BYTE m_nImgFormat; // =0 cif ; = 1 qcif char *m_sIPAddress; char *m_sUserName; char *m_sUserPassword; BOOL m_bUserCheck; HWND m_hShowVideo; }CLIENT_VIDEOINFO, *PCLIENT_VIDEOINFO; CPLAYER_API LONG __stdcall MP4_ClientStart(PCLIENT_VIDEOINFO pClientinfo,void(CALLBACK *ReadDataCallBack)(DWORD nPort,UCHAR *pPacketBuffer,DWORD nPacketSize)); void CALLBACK ReadDataCallBack(DWORD nPort,UCHAR *pPacketBuffer,DWORD nPacketSize) { TRACE("%d\n",nPacketSize); } ..... aa5.m_sUserName = "123"; aa5.m_sUserPassword="w"; aa5.m_bUserCheck = TRUE; MP4_ClientSetTTL(64); nn1 = MP4_ClientStart(&aa5,ReadDataCallBack); if (nn1 == -1) { MessageBox("error"); return; } SDK description: MP4_ClientStart This function starts a connection. The format of the call is: LONG __stdcall MP4_ClientStart(PCLIENT_VIDEOINFO pClientinfo, void(*ReadDataCallBack)(DWORD nChannel,UCHAR *pPacketBuffer,DWORD nPacketSize)) Parameters pClientinfo holds the information. of this connection. nChannel holds the channel of card. pPacketBuffer holds the pointer to the receive buffer. nPacketSize holds the length of the receive buffer. Return Values If the function succeeds the return value is the context of this connection. If the function fails the return value is -1. Remarks typedef struct{ BYTE m_bRemoteChannel; BYTE m_bSendMode; BYTE m_bImgFormat; char *m_sIPAddress; char *m_sUserName; char *m_sUserPassword; BOOL m_bUserCheck; HWND m_hShowVideo; } CLIENT_VIDEOINFO, * PCLIENT_VIDEOINFO; m_bRemoteChannel holds the channel which the client wants to connect to. m_bSendMode holds the network mode of the connection. m_bImgFormat : Image format, 0 is main channel video, 1 is sub channel video m_sIPAddress holds the IP address of the server. m_sUserName holds the user’s name. m_sUserPassword holds the user’s password. m_bUserCheck holds the value whether sends the user’s name and password or not. m_hShowVideo holds Handle for this video window. If m_hShowVideo holds NULL, the client can be record only without decoder. If m_bUserCheck is FALSE, we will send m_sUserName and m_sUserPassword as NULL, else we will send each 50 bytes. The length of m_sIPAddress and m_sUserName must be more than 50 bytes. ReadDataCallBack: When the library receives a packet from a server, this callback is called. My VB.Net code: Imports System.Runtime.InteropServices Public Class Form1 Const WM_USER = &H400 Public Structure CLIENT_VIDEOINFO Public m_bRemoteChannel As Byte Public m_bSendMode As Byte Public m_bImgFormat As Byte Public m_sIPAddress As String Public m_sUserName As String Public m_sUserPassword As String Public m_bUserCheck As Boolean Public m_hShowVideo As Long 'hWnd End Structure Public Declare Function MP4_ClientSetNetPort Lib "hikclient.dll" (ByVal dServerPort As Integer, ByVal dClientPort As Integer) As Boolean Public Declare Function MP4_ClientStartup Lib "hikclient.dll" (ByVal nMessage As UInteger, ByVal hWnd As System.IntPtr) As Boolean <DllImport("hikclient.dll")> Public Shared Function MP4_ClientStart(ByVal Clientinfo As CLIENT_VIDEOINFO, ByRef ReadDataCallBack As CALLBACKdel) As Long End Function Public Delegate Sub CALLBACKdel(ByVal nPort As Long, <MarshalAs(UnmanagedType.LPArray)> ByRef pPacketBuffer As Byte(), ByVal nPacketSize As Long) Public Sub CALLBACK(ByVal nPort As Long, <MarshalAs(UnmanagedType.LPArray)> ByRef pPacketBuffer As Byte(), ByVal nPacketSize As Long) End Sub Public mydel As New CALLBACKdel(AddressOf CALLBACK) Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load Dim Clientinfo As New CLIENT_VIDEOINFO() Clientinfo.m_bRemoteChannel = 0 Clientinfo.m_bSendMode = 0 Clientinfo.m_bImgFormat = 0 Clientinfo.m_sIPAddress = "193.168.1.100" Clientinfo.m_sUserName = "1" Clientinfo.m_sUserPassword = "a" Clientinfo.m_bUserCheck = False Clientinfo.m_hShowVideo = Me.Handle 'Nothing MP4_ClientSetNetPort(850, 850) MP4_ClientStartup(WM_USER + 1, Me.Handle) MP4_ClientStart(Clientinfo, mydel) End Sub End Class here is some other examples of the code in: C# http://blog.csdn.net/nenith1981/archive/2007/09/17/1787692.aspx VB ://read.pudn.com/downloads70/sourcecode/graph/250633/MD%E5%AE%A2%E6%88%B7%E7%AB%AF%28VB%29/hikclient.bas__.htm ://read.pudn.com/downloads70/sourcecode/graph/250633/MD%E5%AE%A2%E6%88%B7%E7%AB%AF%28VB%29/Form1.frm__.htm Delphi ://read.pudn.com/downloads91/sourcecode/multimedia/streaming/349759/Delphi_client/Unit1.pas__.htm

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  • Running code when all threads are finished processing.

    - by rich97
    Quick note: Java and Android noob here, I'm open to you telling me I'm stupid (as long as you tell me why.) I have an android application which requires me start multiple threads originating from various classes and only advance to the next activity once all threads have done their job. I also want to add a "failsafe" timeout in case one the the threads takes too long (HTTP request taking too long or something.) I searched Stack Overflow and found a post saying that I should create a class to keep a running total of open threads and then use a timer to poll for when all the threads are completed. I think I've created a working class to do this for me, it's untested as of yet but has no errors showing in eclipse. Is this a correct implementation? Are there any APIs that I should be made aware of (such as classes in the Java or Android APIs that could be used in place of the abstract classes at the bottom of the class?) package com.dmp.geofix.libs; import java.util.ArrayList; import java.util.Iterator; import java.util.Timer; import java.util.TimerTask; public class ThreadMonitor { private Timer timer = null; private TimerTask timerTask = null; private OnSuccess onSuccess = null; private OnError onError = null; private static ArrayList<Thread> threads; private final int POLL_OPEN_THREADS = 100; private final int TIMEOUT = 10000; public ThreadMonitor() { timerTask = new PollThreadsTask(); } public ThreadMonitor(OnSuccess s) { timerTask = new PollThreadsTask(); onSuccess = s; } public ThreadMonitor(OnError e) { timerTask = new PollThreadsTask(); onError = e; } public ThreadMonitor(OnSuccess s, OnError e) { timerTask = new PollThreadsTask(); onSuccess = s; onError = e; } public void start() { Iterator<Thread> i = threads.iterator(); while (i.hasNext()) { i.next().start(); } timer = new Timer(); timer.schedule(timerTask, 0, POLL_OPEN_THREADS); } public void finish() { Iterator<Thread> i = threads.iterator(); while (i.hasNext()) { i.next().interrupt(); } threads.clear(); timer.cancel(); } public void addThread(Thread t) { threads.add(t); } public void removeThread(Thread t) { threads.remove(t); t.interrupt(); } class PollThreadsTask extends TimerTask { private int timeElapsed = 0; @Override public void run() { timeElapsed += POLL_OPEN_THREADS; if (timeElapsed <= TIMEOUT) { if (threads.isEmpty() == false) { if (onSuccess != null) { onSuccess.run(); } } } else { if (onError != null) { onError.run(); } finish(); } } } public abstract class OnSuccess { public abstract void run(); } public abstract class OnError { public abstract void run(); } }

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  • Why am I getting an IndexOutOfBoundsException here?

    - by Berzerker
    I'm getting an index out of bounds exception thrown and I don't know why, within my replaceValue method below. [null, (10,4), (52,3), (39,9), (78,7), (63,8), (42,2), (50,411)] replacement value test:411 size=7 [null, (10,4), (52,3), (39,9), (78,7), (63,8), (42,2), (50,101)] removal test of :(10,4) [null, (39,9), (52,3), (42,2), (78,7), (63,8), (50,101)] size=6 I try to replace the value again here and get an error... package heappriorityqueue; import java.util.*; public class HeapPriorityQueue<K,V> { protected ArrayList<Entry<K,V>> heap; protected Comparator<K> comp; int size = 0; protected static class MyEntry<K,V> implements Entry<K,V> { protected K key; protected V value; protected int loc; public MyEntry(K k, V v,int i) {key = k; value = v;loc =i;} public K getKey() {return key;} public V getValue() {return value;} public int getLoc(){return loc;} public String toString() {return "(" + key + "," + value + ")";} void setKey(K k1) {key = k1;} void setValue(V v1) {value = v1;} public void setLoc(int i) {loc = i;} } public HeapPriorityQueue() { heap = new ArrayList<Entry<K,V>>(); heap.add(0,null); comp = new DefaultComparator<K>(); } public HeapPriorityQueue(Comparator<K> c) { heap = new ArrayList<Entry<K,V>>(); heap.add(0,null); comp = c; } public int size() {return size;} public boolean isEmpty() {return size == 0; } public Entry<K,V> min() throws EmptyPriorityQueueException { if (isEmpty()) throw new EmptyPriorityQueueException("Priority Queue is Empty"); return heap.get(1); } public Entry<K,V> insert(K k, V v) { size++; Entry<K,V> entry = new MyEntry<K,V>(k,v,size); heap.add(size,entry); upHeap(size); return entry; } public Entry<K,V> removeMin() throws EmptyPriorityQueueException { if (isEmpty()) throw new EmptyPriorityQueueException("Priority Queue is Empty"); if (size == 1) return heap.remove(1); Entry<K,V> min = heap.get(1); heap.set(1, heap.remove(size)); size--; downHeap(1); return min; } public V replaceValue(Entry<K,V> e, V v) throws InvalidEntryException, EmptyPriorityQueueException { // replace the value field of entry e in the priority // queue with the given value v, and return the old value This is where I am getting the IndexOutOfBounds exception, on heap.get(i); if (isEmpty()){ throw new EmptyPriorityQueueException("Priority Queue is Empty."); } checkEntry(e); int i = e.getLoc(); Entry<K,V> entry=heap.get(((i))); V oldVal = entry.getValue(); K key=entry.getKey(); Entry<K,V> insert = new MyEntry<K,V>(key,v,i); heap.set(i, insert); return oldVal; } public K replaceKey(Entry<K,V> e, K k) throws InvalidEntryException, EmptyPriorityQueueException, InvalidKeyException { // replace the key field of entry e in the priority // queue with the given key k, and return the old key if (isEmpty()){ throw new EmptyPriorityQueueException("Priority Queue is Empty."); } checkKey(k); checkEntry(e); K oldKey=e.getKey(); int i = e.getLoc(); Entry<K,V> entry = new MyEntry<K,V>(k,e.getValue(),i); heap.set(i,entry); downHeap(i); upHeap(i); return oldKey; } public Entry<K,V> remove(Entry<K,V> e) throws InvalidEntryException, EmptyPriorityQueueException{ // remove entry e from priority queue and return it if (isEmpty()){ throw new EmptyPriorityQueueException("Priority Queue is Empty."); } MyEntry<K,V> entry = checkEntry(e); if (size==1){ return heap.remove(size--); } int i = e.getLoc(); heap.set(i, heap.remove(size--)); downHeap(i); return entry; } protected void upHeap(int i) { while (i > 1) { if (comp.compare(heap.get(i/2).getKey(), heap.get(i).getKey()) <= 0) break; swap(i/2,i); i = i/2; } } protected void downHeap(int i) { int smallerChild; while (size >= 2*i) { smallerChild = 2*i; if ( size >= 2*i + 1) if (comp.compare(heap.get(2*i + 1).getKey(), heap.get(2*i).getKey()) < 0) smallerChild = 2*i+1; if (comp.compare(heap.get(i).getKey(), heap.get(smallerChild).getKey()) <= 0) break; swap(i, smallerChild); i = smallerChild; } } protected void swap(int j, int i) { heap.get(j).setLoc(i); heap.get(i).setLoc(j); Entry<K,V> temp; temp = heap.get(j); heap.set(j, heap.get(i)); heap.set(i, temp); } public String toString() { return heap.toString(); } protected MyEntry<K,V> checkEntry(Entry<K,V> ent) throws InvalidEntryException { if(ent == null || !(ent instanceof MyEntry)) throw new InvalidEntryException("Invalid entry."); return (MyEntry)ent; } protected void checkKey(K key) throws InvalidKeyException{ try{comp.compare(key,key);} catch(Exception e){throw new InvalidKeyException("Invalid key.");} } }

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  • Binding an Ilist to datagridview containing another object in a field

    - by JaSk
    I have pretty much the same problem as this question http://stackoverflow.com/questions/970741 but in windows forms, can anyone help me solve it? this is my code, so you don't have to check the other question: public class Material { public virtual int id { get; private set; } public virtual string nombre { get; set; } public virtual string unidad { get; set; } public virtual Categorias Categoria { get; set; } public virtual IList Materiales { get; set; } public Material() { Materiales = new List<Materiales>(); } public virtual void AddMateriales(Materiales materiales) { materiales.Material = this; this.Materiales.Add(materiales); } } as you can see I have an object within the IList so when I use the List as the data source for a datagridview I get a object.categoria where I want to get the Categoria.Name property, can anyone help me?. Thanks

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  • Java Inheritance - Getting a Parameter from Parent Class

    - by Aaron
    I'm trying to take one parameter from the parent class of Car and add it to my array (carsParked), how can i do this? Parent Class public class Car { protected String regNo; //Car registration number protected String owner; //Name of the owner protected String carColor; /** Creates a Car object * @param rNo - registration number * @param own - name of the owner **/ public Car (String rNo, String own, String carColour) { regNo = rNo; owner = own; carColor = carColour; } /** @return The car registration number **/ public String getRegNo() { return regNo; } /** @return A String representation of the car details **/ public String getAsString() { return "Car: " + regNo + "\nColor: " + carColor; } public String getColor() { return carColor; } } Child Class public class Carpark extends Car { private String location; // Location of the Car Park private int capacity; // Capacity of the Car Park - how many cars it can hold private int carsIn; // Number of cars currently in the Car Park private String[] carsParked; /** Constructor for Carparks * @param loc - the Location of the Carpark * @param cap - the Capacity of the Carpark */ public Carpark (String locations, int room) { location = locations; capacity = room; } /** Records entry of a car into the car park */ public void driveIn() { carsIn = carsIn + 1; } /** Records the departure of a car from the car park */ public void driveOut() { carsIn = carsIn - 1; } /** Returns a String representation of information about the carpark */ public String getAsString() { return location + "\nCapacity: " + capacity + " Currently parked: " + carsIn + "\n*************************\n"; } }

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  • How to best propagate changes upwards a hierarchical structure for binding?

    - by H.B.
    If i have a folder-like structure that uses the composite design pattern and i bind the root folder to a TreeView. It would be quite useful if i can display certain properties that are being accumulated from the folder's contents. The question is, how do i best inform the folder that changes occurred in a child-element so that the accumulative properties get updated? The context in which i need this is a small RSS-FeedReader i am trying to make. This are the most important objects and aspects of my model: Composite interface: public interface IFeedComposite : INotifyPropertyChanged { string Title { get; set; } int UnreadFeedItemsCount { get; } ObservableCollection<FeedItem> FeedItems { get; } } FeedComposite (aka Folder) public class FeedComposite : BindableObject, IFeedComposite { private string title = ""; public string Title { get { return title; } set { title = value; NotifyPropertyChanged("Title"); } } private ObservableCollection<IFeedComposite> children = new ObservableCollection<IFeedComposite>(); public ObservableCollection<IFeedComposite> Children { get { return children; } set { children.Clear(); foreach (IFeedComposite item in value) { children.Add(item); } NotifyPropertyChanged("Children"); } } public FeedComposite() { } public FeedComposite(string title) { Title = title; } public ObservableCollection<FeedItem> FeedItems { get { ObservableCollection<FeedItem> feedItems = new ObservableCollection<FeedItem>(); foreach (IFeedComposite child in Children) { foreach (FeedItem item in child.FeedItems) { feedItems.Add(item); } } return feedItems; } } public int UnreadFeedItemsCount { get { return (from i in FeedItems where i.IsUnread select i).Count(); } } Feed: public class Feed : BindableObject, IFeedComposite { private string url = ""; public string Url { get { return url; } set { url = value; NotifyPropertyChanged("Url"); } } ... private ObservableCollection<FeedItem> feedItems = new ObservableCollection<FeedItem>(); public ObservableCollection<FeedItem> FeedItems { get { return feedItems; } set { feedItems.Clear(); foreach (FeedItem item in value) { AddFeedItem(item); } NotifyPropertyChanged("Items"); } } public int UnreadFeedItemsCount { get { return (from i in FeedItems where i.IsUnread select i).Count(); } } public Feed() { } public Feed(string url) { Url = url; } Ok, so here's the thing, if i bind a TextBlock.Text to the UnreadFeedItemsCount there won't be simple notifications when an item is marked unread, so one of my approaches has been to handle the PropertyChanged event of every FeedItem and if the IsUnread-Property is changed i have my Feed make a notification that the property UnreadFeedItemsCount has been changed. With this approach i also need to handle all PropertyChanged events of all Feeds and FeedComposites in Children of FeedComposite, from the sound of it, it should be obvious that this is not such a very good idea, you need to be very careful that items never get added or removed to any collection without having attached the PropertyChanged event handler first and things like that. Also: What do i do with the CollectionChanged-Events which necessarily also cause a change in the sum of the unread items count? Sounds like more event handling fun. It is such a mess, it would be great if anyone has an elegant solution to this since i don't want the feed-reader to end up as awful as my first attempt years ago when i didn't even know about DataBinding...

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  • C# Reflection and Getting Properties

    - by Nathan
    I have the following dummy class structure and I am trying to find out how to get the properties from each instance of the class People in PeopleList. I know how to get the properties from a single instance of People but can't for the life of me figure out how to get it from PeopleList. I am sure this is really straightforward but can someone point me in the right direction? public class Example { public class People { private string _name; public string Name { get { return _name; } set { _name = value; } } private int _age; public int Age { get { return _age; } set { _age = value; } } public People() { } public People(string name, int age) { this._name = name; this._age = age; } } public class PeopleList : List<People> { public static void DoStuff() { PeopleList newList = new PeopleList(); // Do some stuff newList.Add(new People("Tim", 35)); } } }

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  • Class constructor in java

    - by aladine
    Please advise me the difference between two ways of declaration of java constructor public class A{ private static A instance = new A(); public static A getInstance() { return instance; } public static void main(String[] args) { A a= A.getInstance(); } } AND public class B{ public B(){}; public static void main(String[] args) { B b= new B(); } } Thanks

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  • <string xmlns=''> was not expected in c#

    - by Nishant
    Hi all I am trying to serialize value in xml. Every time I am getting <string xmlns=''> was not expected in c# Not able to find root cause plz help me out here. namespace CustomDataType.usercontrols { public partial class CustomDataTypes : System.Web.UI.UserControl, umbraco.editorControls.userControlGrapper.IUsercontrolDataEditor { private Status _umbval; public object value { get { var status = GetStatus(); return SerializationHelper.ValueToXmlString(status); } set { //if (value == null || string.IsNullOrEmpty(value.ToString())) //{ // _umbval = Status.Empty; //} //else //{ _umbval =(Status)SerializationHelper.ValueFromXmlString(value,typeof(Status)); //} } } } } using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Xml.Serialization; namespace CustomDataType { [Serializable] [XmlRoot("StatuMain")] public class Status { [XmlElement("statusvalue")] public string StatusValue { get; set; } [XmlElement("statusvalue1")] public string StatusValue1 { get; set; } [XmlElement("statusvalue2")] public string StatusValue2 { get; set; } [XmlElement("statusvalue3")] public string StatusValue3 { get; set; } //[XmlElement("isEmailChecked")] //public bool HasEmailChecked { get; set; } //[XmlElement("datetime")] //public DateTime Date { get; set; } public static Status Empty { get { var schedule = new Status(); schedule = null; return schedule; } } } }

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  • J-Monkey subclass

    - by user2971104
    I'm new in java and J-monkey and I'm trying to make a java game so for the Menu I have made a enum so I can Switch between any of my State but I want to keep the main file shorter so it can be easily to read so I'm making subclass the problem is that when run the game it give me an error that say "Uncaught exception thrown in Thread[LWJGL Renderer Thread,5,main] NullPointerException" I think this problem has to be something whit the pipeline Here is the code of my main file: package mygame; import com.jme3.app.SimpleApplication; import com.jme3.font.BitmapText; import com.jme3.material.Material; import com.jme3.math.ColorRGBA; import com.jme3.math.Vector3f; import com.jme3.renderer.RenderManager; import com.jme3.scene.Spatial; import com.jme3.scene.Geometry; import com.jme3.input.*; import com.jme3.input.controls.*; public class Main extends SimpleApplication { //GameStates enum GameState{Logo, Menu, Playing, Option}; GameState gameState = GameState.Logo; //Class Variables Logo logo; public Main() { logo = new Logo(); } public static void main(String[] args) { Main app = new Main(); app.start(); } public static void logo(String[] args) { Logo app = new Logo(); app.start(); } @Override public void simpleInitApp() { //Load flyCam.setMoveSpeed(20); if(gameState == GameState.Logo){ logo.simpleInitApp(); } } @Override public void simpleUpdate(float tpf) { } @Override public void simpleRender(RenderManager rm) { //TODO: add render code //Load if(gameState == GameState.Logo) { } } } And here is my Logo subclass: package mygame; import com.jme3.app.SimpleApplication; import com.jme3.renderer.RenderManager; import com.jme3.scene.Spatial; public class Logo extends SimpleApplication { @Override public void simpleInitApp() { Spatial Logo_Model = assetManager.loadModel("Models/Teapot/Logo.obj"); rootNode.attachChild(Logo_Model); } public void simpleRender(RenderManager rm) { //Load } }

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  • Help with listView in Android

    - by jul
    Hi, I'm just starting with Android and can't find how to display a list in my activity. I get some restaurant data from a web service and I'd like to show the results in a list. The activity, the restaurant class and the layout main.xml are shown below. How can I display, for instance, the list of the restaurant names in the ListView 'list' of my layout? thank you Jul public class Atable extends ListActivity { RestaurantList restaurantList; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); //Here I set restaurantList //Now how can I display, for example, the list of the names of the restaurants } main.xml <LinearLayout android:orientation="horizontal" android:layout_width="fill_parent" android:layout_height="wrap_content"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/search" /> <EditText android:id="@+id/search" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_weight="1"/> </LinearLayout> <LinearLayout android:orientation="vertical" android:layout_width="wrap_content" android:layout_height="wrap_content"> <ListView android:id="@+id/android:list" android:layout_width="wrap_content" android:layout_height="wrap_content"/> <TextView android:id="@+id/android:empty" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/noresults"/> </LinearLayout> </LinearLayout> Restaurant list class package org.digitalfarm.atable; import java.util.List; public class RestaurantList { private List<Restaurant> restaurants; public List<Restaurant> getRestaurants() { return restaurants; } public void setRestaurants(List<Restaurant> restaurants) { this.restaurants = restaurants; } } Restaurant class package org.digitalfarm.atable; public class Restaurant { private String name; private float latitude; private float longitude; public String getName() { return name; } public void setName(String name) { this.name = name; } public float getLatitude() { return latitude; } public void setLatitude(float latitude) { this.latitude = latitude; } public float getLongitude() { return longitude; } public void setLongitude(float longitude) { this.longitude = longitude; } }

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  • Problem painting JLabel class to another JPanel class

    - by jjpotter
    I have created a class that extends JLabel to use as my object moving around a JPanel for a game. import javax.swing.*; public class Head extends JLabel { int xpos; int ypos; int xvel; int yvel; ImageIcon chickie = new ImageIcon("C:\\Users\\jjpotter.MSDOM1\\Pictures\\clavalle.jpg"); JLabel myLabel = new JLabel(chickie); public Head(int xpos, int ypos, int xvel, int yvel){ this.xpos = xpos; this.ypos = ypos; this.xvel = xvel; this.yvel = yvel; } public void draw(){ myLabel.setLocation(xpos, ypos); } public double getXpos() { return xpos; } public double getYpos() { return ypos; } public int getXvel() { return xvel; } public int getYvel() { return yvel; } public void setPos(int x, int y){ xpos = x; ypos = y; } } I am then trying to add it onto my JPanel. From here I will randomly have it increment its x and y coordinates to float it around the screen. I can not get it to paint itself onto the JPanel. I know there is a key concept I am missing here that involves painting components on different panels. Here is what I have in my GamePanel class import java.awt.Dimension; import java.util.Random; import javax.swing.*; public class GamePanel extends JPanel { Random myRand = new Random(); Head head = new Head(20,20,0,0); public GamePanel(){ this.setSize(new Dimension(640, 480)); this.add(head); } } Any suggestions on how to get this to add to the JPanel? Also, is this a good way to go about having the picture float around the screen randomly for a game?

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  • Making Visual C++ DLL from C++ class

    - by prosseek
    I have the following C++ code to make dll (Visual Studio 2010). class Shape { public: Shape() { nshapes++; } virtual ~Shape() { nshapes--; }; double x, y; void move(double dx, double dy); virtual double area(void) = 0; virtual double perimeter(void) = 0; static int nshapes; }; class __declspec(dllexport) Circle : public Shape { private: double radius; public: Circle(double r) : radius(r) { }; virtual double area(void); virtual double perimeter(void); }; class __declspec(dllexport) Square : public Shape { private: double width; public: Square(double w) : width(w) { }; virtual double area(void); virtual double perimeter(void); }; I have the __declspec, class __declspec(dllexport) Circle I could build a dll with the following command CL.exe /c example.cxx link.exe /OUT:"example.dll" /DLL example.obj When I tried to use the library, Square* square; square->area() I got the error messages. What's wrong or missing? example_unittest.obj : error LNK2001: unresolved external symbol "public: virtual double __thiscall ... Square::area(void)" (?area@Square@@UAENXZ) ADDED Following wengseng's answer, I modified the header file, and for DLL C++ code, I added #define XYZLIBRARY_EXPORT However, I still got errors. example_unittest.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __th iscall Circle::Circle(double)" (__imp_??0Circle@@QAE@N@Z) referenced in function "protected: virtual void __thiscall TestOne::SetUp(void)" (?SetUp@TestOne@@MAEXXZ) example_unittest.obj : error LNK2019: unresolved external symbol "__declspec(dllimport) public: __th iscall Square::Square(double)" (__imp_??0Square@@QAE@N@Z) referenced in function "protected: virtual void __thiscall TestOne::SetUp(void)" (?SetUp@TestOne@@MAEXXZ) example_unittest.obj : error LNK2001: unresolved external symbol "public: virtual double __thiscall Square::area(void)" (?area@Square@@UAENXZ) example_unittest.obj : error LNK2001: unresolved external symbol "public: virtual double __thiscall Square::perimeter(void)" (?perimeter@Square@@UAENXZ) example_unittest.obj : error LNK2001: unresolved external symbol "public: virtual double __thiscall Circle::area(void)" (?area@Circle@@UAENXZ) example_unittest.obj : error LNK2001: unresolved external symbol "public: virtual double __thiscall Circle::perimeter(void)" (?perimeter@Circle@@UAENXZ)

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  • ASP.NET MVC View Not posting back to Post method and expecting a parameterless Constructor?

    - by VJ
    Hi, I am trying to post back some data using a viewmodel i have created and it works for me for one of the projects.But I am doin this right now public ActionResult Foo(string userkey) { vm.Value="Xvalue"; return View(vm); } [HttpPost] public ActionResult Foo( MyViewModel vm) { // process input if (inputOK) string value=vm.Value return RedirectToAction("Index"); return View(); } public class MyViewModel { public string Value { get; set; } public SomeClass newobj {get;set;} } public class SomeClass { public int id{get;set;} public string str{get;set;} } So it on debugging never goes into the parameter method for Post although on the view i have added a form and a button that submits and the page inherits from the viewmodel.I get an error saying it expects a parameterless constructor how do I fix this ? . I wrote an post method with no parameters and it does go into that method

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  • How to set order of appearance for fields when using Html.EditorFor in MVC 2?

    - by Anrie
    I have the following classes in my Model: public abstract class Entity : IEntity { [ScaffoldColumn(false)] public int Id { get; set; } [Required,StringLength(500)] public string Name { get; set; } } and public class Model : SortableEntity { [Required] public ModelType Type { get; set; } [ListRequired] public List<Producer> Producers { get; set; } public List<PrintArea> PrintAreas { get; set; } public List<Color> Colors { get; set; } } To display the "Model" class in the view I simply call Html.EditorFor(model=model), but the "Name" property of the base class is rendered last, which is not the desired behaviour. Is it possible to influenece on the order of displayed fields somehow?

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  • How to refresh a fragment in a viewpager?

    - by aut_silvia
    I know there are already some questions to this problem. But I am really new in Android and ecspecially to Fragments and Viewpager. Pls have passion with me. I didn't found a answer which fits to my code. I dont know how to refresh a fragment or reload it when it's "active" again. TabsPagerAdapter.java: public class TabsPagerAdapter extends FragmentPagerAdapter{ public TabsPagerAdapter(FragmentManager fm){ super(fm); } @Override public Fragment getItem(int index) { switch (index) { case 0: return new KFZFragment(); case 1: return new LogFragment(); case 2: return new TrackFragment(); } return null; } @Override public int getCount() { // get item count - equal to number of tabs return 3; } } I have this 3 Fragments (KFZFragment,LogFragment,TrackFragment) and on the TrackFragment I calculate some data and this data should be display in a ListView in LogFragment. But when I change to LogFragment it's not the latest data. So it doesnt refresh. Now how should I modify my code to refresh the fragments when it's "active"? MainActivityFragment.java: public class MainActivityFragment extends FragmentActivity implements ActionBar.TabListener{ private ViewPager viewPager; private TabsPagerAdapter mAdapter; private ActionBar actionBar; List<Fragment> fragments; private String[] tabs = { "KFZ", "Fahrten Log", "Kosten Track" }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main_fragment); // Initilization viewPager = (ViewPager) findViewById(R.id.pager); actionBar = getActionBar(); mAdapter = new TabsPagerAdapter(getSupportFragmentManager()); fragments = new Vector<Fragment>(); fragments.add(Fragment.instantiate(this, KFZFragment.class.getName(),savedInstanceState)); fragments.add(Fragment.instantiate(this, LogFragment.class.getName(),savedInstanceState)); viewPager.setAdapter(mAdapter); actionBar.setHomeButtonEnabled(false); actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); // Adding Tabs for (String tab_name : tabs) { actionBar.addTab(actionBar.newTab().setText(tab_name) .setTabListener(this)); } viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() { @Override public void onPageSelected(int position) { // on changing the page // make respected tab selected actionBar.setSelectedNavigationItem(position); } @Override public void onPageScrolled(int arg0, float arg1, int arg2) { } @Override public void onPageScrollStateChanged(int arg0) { } }); } @Override public void onTabReselected(Tab tab, FragmentTransaction ft) { // TODO Auto-generated method stub } @Override public void onTabSelected(Tab tab, FragmentTransaction ft) { viewPager.setCurrentItem(tab.getPosition()); } @Override public void onTabUnselected(Tab tab, FragmentTransaction ft) { // TODO Auto-generated method stub } @Override public boolean onKeyDown(int keyCode, KeyEvent event) { if (keyCode == KeyEvent.KEYCODE_BACK) { } return super.onKeyDown(keyCode, event); } } Pls help me out.

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  • How to generalize a method call in Java (to avoid code duplication)

    - by dln385
    I have a process that needs to call a method and return its value. However, there are several different methods that this process may need to call, depending on the situation. If I could pass the method and its arguments to the process (like in Python), then this would be no problem. However, I don't know of any way to do this in Java. Here's a concrete example. (This example uses Apache ZooKeeper, but you don't need to know anything about ZooKeeper to understand the example.) The ZooKeeper object has several methods that will fail if the network goes down. In this case, I always want to retry the method. To make this easy, I made a "BetterZooKeeper" class that inherits the ZooKeeper class, and all of its methods automatically retry on failure. This is what the code looked like: public class BetterZooKeeper extends ZooKeeper { private void waitForReconnect() { // logic } @Override public Stat exists(String path, Watcher watcher) { while (true) { try { return super.exists(path, watcher); } catch (KeeperException e) { // We will retry. } waitForReconnect(); } } @Override public byte[] getData(String path, boolean watch, Stat stat) { while (true) { try { return super.getData(path, watch, stat); } catch (KeeperException e) { // We will retry. } waitForReconnect(); } } @Override public void delete(String path, int version) { while (true) { try { super.delete(path, version); return; } catch (KeeperException e) { // We will retry. } waitForReconnect(); } } } (In the actual program there is much more logic and many more methods that I took out of the example for simplicity.) We can see that I'm using the same retry logic, but the arguments, method call, and return type are all different for each of the methods. Here's what I did to eliminate the duplication of code: public class BetterZooKeeper extends ZooKeeper { private void waitForReconnect() { // logic } @Override public Stat exists(final String path, final Watcher watcher) { return new RetryableZooKeeperAction<Stat>() { @Override public Stat action() { return BetterZooKeeper.super.exists(path, watcher); } }.run(); } @Override public byte[] getData(final String path, final boolean watch, final Stat stat) { return new RetryableZooKeeperAction<byte[]>() { @Override public byte[] action() { return BetterZooKeeper.super.getData(path, watch, stat); } }.run(); } @Override public void delete(final String path, final int version) { new RetryableZooKeeperAction<Object>() { @Override public Object action() { BetterZooKeeper.super.delete(path, version); return null; } }.run(); return; } private abstract class RetryableZooKeeperAction<T> { public abstract T action(); public final T run() { while (true) { try { return action(); } catch (KeeperException e) { // We will retry. } waitForReconnect(); } } } } The RetryableZooKeeperAction is parameterized with the return type of the function. The run() method holds the retry logic, and the action() method is a placeholder for whichever ZooKeeper method needs to be run. Each of the public methods of BetterZooKeeper instantiates an anonymous inner class that is a subclass of the RetryableZooKeeperAction inner class, and it overrides the action() method. The local variables are (strangely enough) implicitly passed to the action() method, which is possible because they are final. In the end, this approach does work and it does eliminate the duplication of the retry logic. However, it has two major drawbacks: (1) it creates a new object every time a method is called, and (2) it's ugly and hardly readable. Also I had to workaround the 'delete' method which has a void return value. So, here is my question: is there a better way to do this in Java? This can't be a totally uncommon task, and other languages (like Python) make it easier by allowing methods to be passed. I suspect there might be a way to do this through reflection, but I haven't been able to wrap my head around it.

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  • How to copy value from class X to class Y with the same property name in c#?

    - by Samnang
    Suppose I have two classes: public class Student { public int Id {get; set;} public string Name {get; set;} public IList<Course> Courses{ get; set;} } public class StudentDTO { public int Id {get; set;} public string Name {get; set;} public IList<CourseDTO> Courses{ get; set;} } I would like to copy value from Student class to StudentDTO class: var student = new Student(); StudentDTO studentDTO = student; How can I do that by reflection or other solution?

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  • Where in the standard is forwarding to a base class required in these situations?

    - by pgast
    Maybe even better is: Why does the standard require forwarding to a base class in these situations? (yeah yeah yeah - Why? - Because.) class B1 { public: virtual void f()=0; }; class B2 { public: virtual void f(){} }; class D : public B1,public B2{ }; class D2 : public B1,public B2{ public: using B2::f; }; class D3 : public B1,public B2{ public: void f(){ B2::f(); } }; D d; D2 d2; D3 d3; EDG gives: sourceFile.cpp sourceFile.cpp(24) : error C2259: 'D' : cannot instantiate abstract class due to following members: 'void B1::f(void)' : is abstract sourceFile.cpp(6) : see declaration of 'B1::f' sourceFile.cpp(25) : error C2259: 'D2' : cannot instantiate abstract class due to following members: 'void B1::f(void)' : is abstract sourceFile.cpp(6) : see declaration of 'B and similarly for the MS compiler. I might buy the first case,D. But in D2 - f is unambiguously defined by the using declaration, why is that not enough for the compiler to be required to fill out the vtable? Where in the standard is this situation defined?

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  • Resolving a Forward Declaration Issue Involving a State Machine in C++

    - by hypersonicninja
    I've recently returned to C++ development after a hiatus, and have a question regarding implementation of the State Design Pattern. I'm using the vanilla pattern, exactly as per the GoF book. My problem is that the state machine itself is based on some hardware used as part of an embedded system - so the design is fixed and can't be changed. This results in a circular dependency between two of the states (in particular), and I'm trying to resolve this. Here's the simplified code (note that I tried to resolve this by using headers as usual but still had problems - I've omitted them in this code snippet): #include <iostream> #include <memory> using namespace std; class Context { public: friend class State; Context() { } private: State* m_state; }; class State { public: State() { } virtual void Trigger1() = 0; virtual void Trigger2() = 0; }; class LLT : public State { public: LLT() { } void Trigger1() { new DH(); } void Trigger2() { new DL(); } }; class ALL : public State { public: ALL() { } void Trigger1() { new LLT(); } void Trigger2() { new DH(); } }; // DL needs to 'know' about DH. class DL : public State { public: DL() { } void Trigger1() { new ALL(); } void Trigger2() { new DH(); } }; class HLT : public State { public: HLT() { } void Trigger1() { new DH(); } void Trigger2() { new DL(); } }; class AHL : public State { public: AHL() { } void Trigger1() { new DH(); } void Trigger2() { new HLT(); } }; // DH needs to 'know' about DL. class DH : public State { public: DH () { } void Trigger1() { new AHL(); } void Trigger2() { new DL(); } }; int main() { auto_ptr<LLT> llt (new LLT); auto_ptr<ALL> all (new ALL); auto_ptr<DL> dl (new DL); auto_ptr<HLT> hlt (new HLT); auto_ptr<AHL> ahl (new AHL); auto_ptr<DH> dh (new DH); return 0; } The problem is basically that in the State Pattern, state transitions are made by invoking the the ChangeState method in the Context class, which invokes the constructor of the next state. Because of the circular dependency, I can't invoke the constructor because it's not possible to pre-define both of the constructors of the 'problem' states. I had a look at this article, and the template method which seemed to be the ideal solution - but it doesn't compile and my knowledge of templates is a rather limited... The other idea I had is to try and introduce a Helper class to the subclassed states, via multiple inheritance, to see if it's possible to specify the base class's constructor and have a reference to the state subclasse's constructor. But I think that was rather ambitious... Finally, would a direct implmentation of the Factory Method Design Pattern be the best way to resolve the entire problem?

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  • Why do I get a WCF timeout even though my service call and callback are successful?

    - by KallDrexx
    I'm playing around with hooking up an in-game console to a WCF interface, so an external application can send console commands and receive console output. To accomplish this I created the following service contracts: public interface IConsoleNetworkCallbacks { [OperationContract(IsOneWay = true)] void NewOutput(IEnumerable<string> text, string category); } [ServiceContract(SessionMode = SessionMode.Required, CallbackContract = typeof(IConsoleNetworkCallbacks))] public interface IConsoleInterface { [OperationContract] void ProcessInput(string input); [OperationContract] void ChangeCategory(string category); } On the server I implemented it with: public class ConsoleNetworkInterface : IConsoleInterface, IDisposable { public ConsoleNetworkInterface() { ConsoleManager.Instance.RegisterOutputUpdateHandler(OutputHandler); } public void Dispose() { ConsoleManager.Instance.UnregisterOutputHandler(OutputHandler); } public void ProcessInput(string input) { ConsoleManager.Instance.ProcessInput(input); } public void ChangeCategory(string category) { ConsoleManager.Instance.UnregisterOutputHandler(OutputHandler); ConsoleManager.Instance.RegisterOutputUpdateHandler(OutputHandler, category); } protected void OutputHandler(IEnumerable<string> text, string category) { var callbacks = OperationContext.Current.GetCallbackChannel<IConsoleNetworkCallbacks>(); callbacks.NewOutput(text, category); } } On the client I implemented the callback with: public class Callbacks : IConsoleNetworkCallbacks { public void NewOutput(IEnumerable<string> text, string category) { MessageBox.Show(string.Format("{0} lines received for '{1}' category", text.Count(), category)); } } Finally, I establish the service host with the following class: public class ConsoleServiceHost : IDisposable { protected ServiceHost _host; public ConsoleServiceHost() { _host = new ServiceHost(typeof(ConsoleNetworkInterface), new Uri[] { new Uri("net.pipe://localhost") }); _host.AddServiceEndpoint(typeof(IConsoleInterface), new NetNamedPipeBinding(), "FrbConsolePipe"); _host.Open(); } public void Dispose() { _host.Close(); } } and use the following code on my client to establish the connection: protected Callbacks _callbacks; protected IConsoleInterface _proxy; protected void ConnectToConsoleServer() { _callbacks = new Callbacks(); var factory = new DuplexChannelFactory<IConsoleInterface>(_callbacks, new NetNamedPipeBinding(), new EndpointAddress("net.pipe://localhost/FrbConsolePipe")); _proxy = factory.CreateChannel(); _proxy.ProcessInput("Connected"); } So what happens is that my ConnectToConsoleServer() is called and then it gets all the way to _proxy.ProcessInput("Connected");. In my game (on the server) I immediately see the output caused by the ProcessInput call, but the client is still stalled on the _proxy.ProcessInput() call. After a minute my client gets a JIT TimeoutException however at the same time my MessageBox message appears. So obviously not only is my command being sent immediately, my callback is being correctly called. So why am I getting a timeout exception? Note: Even removing the MessageBox call, I still have this issue, so it's not an issue of the GUI blocking the callback response.

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