litesoft
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// This Source Code is in the Public Domain per: http://unlicense.org package org.litesoft.GWT.eventbus.client.nonpublic; import java.util.*; import org.litesoft.GWT.eventbus.client.*; public class SubscriptionManager { private Map mSubscribers = new HashMap(); // TargetName to ListenersEntry private String mEBform; public SubscriptionManager( String pEBform ) { mEBform = pEBform; } public synchronized void clear() { mSubscribers.clear(); } public synchronized boolean anySubscribers( String pTargetName ) { return (null != getListenersEntry( pTargetName )); } public synchronized boolean hasPeerAcknowledged( String pTargetName ) { ListenersEntry entry = getListenersEntry( pTargetName ); return (entry != null) && entry.hasPeerAcknowledged(); } public synchronized void setPeerAcknowledged( String pTargetName ) { ListenersEntry entry = getListenersEntry( pTargetName ); if ( entry != null ) { entry.setPeerAcknowledged(); } } public synchronized EventPackageListener[] getListenersFor( String pTargetName ) { ListenersEntry entry = getListenersEntry( pTargetName ); return (entry != null) ? entry.getListeners() : null; } private ListenersEntry getListenersEntry( String pTargetName ) { return (ListenersEntry) mSubscribers.get( pTargetName ); } /** * @return T/F if added first pListener for pTargetName */ public synchronized boolean subscribe( String pTargetName, EventPackageListener pListener ) { ListenersEntry entry = getListenersEntry( pTargetName ); if ( entry == null ) { mSubscribers.put( pTargetName, new ListenersEntry( pListener ) ); return true; // Just Added first Listener for TargetName } entry.add( pListener ); return false; // did NOT just add first one! } /** * @return T/F if removed last pListener for pTargetName */ public synchronized boolean unsubscribe( String pTargetName, EventPackageListener pListener ) { ListenersEntry entry = getListenersEntry( pTargetName ); if ( entry != null ) { if ( entry.remove( pListener ) ) { mSubscribers.remove( pTargetName ); return true; // reduced to nothing } } return false; } public String toString() { return mEBform; } private static class ListenersEntry { private EventPackageListener[] mListeners; private boolean mPeerAcknowledged = false; public ListenersEntry( EventPackageListener pListener ) { mListeners = new EventPackageListener[]{pListener}; } public EventPackageListener[] getListeners() { return mListeners; } public boolean hasPeerAcknowledged() { return mPeerAcknowledged; } public void setPeerAcknowledged() { mPeerAcknowledged = true; } /** * @return T/F if pListener added (not already in the list) */ public boolean add( EventPackageListener pListener ) { EventPackageListener[] newListeners = new EventPackageListener[mListeners.length + 1]; int i = 0; for ( ; i < mListeners.length; i++ ) { if ( pListener == (newListeners[i] = mListeners[i]) ) { return false; } } newListeners[i] = pListener; mListeners = newListeners; return true; } /** * @return T/F if would have reduced to NO listeners */ public boolean remove( EventPackageListener pListener ) { int at = -1; for ( int i = 0; i < mListeners.length; i++ ) { if ( pListener == mListeners[i] ) { at = i; break; } } if ( at == -1 ) { return false; } if ( mListeners.length == 1 ) { return true; // reduced to nothing } EventPackageListener[] newListeners = new EventPackageListener[mListeners.length - 1]; int from = 0, to = 0; while ( from < at ) { newListeners[to++] = mListeners[from++]; } from++; while ( from < mListeners.length ) { newListeners[to++] = mListeners[from++]; } mListeners = newListeners; return false; } } } |