Mercurial > projects > dwt2
view org.eclipse.core.databinding.beans/src/org/eclipse/core/internal/databinding/beans/ListenerSupport.d @ 96:b74ac5dfcc06
package to module and java.lang.all import
author | Frank Benoit <benoit@tionex.de> |
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date | Tue, 21 Apr 2009 11:03:33 +0200 |
parents | 6208d4f6a277 |
children | c86eb8b3098e |
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/******************************************************************************* * Copyright (c) 2005, 2008 IBM Corporation and others. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html * * Contributors: * IBM Corporation - initial API and implementation * Matthew Hall - bug 118516 *******************************************************************************/ module org.eclipse.core.internal.databinding.beans.ListenerSupport; import java.lang.all; import java.beans.PropertyChangeEvent; import java.beans.PropertyChangeListener; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.util.HashSet; import java.util.Iterator; import java.util.Set; import org.eclipse.core.databinding.beans.BeansObservables; import org.eclipse.core.databinding.util.Policy; import org.eclipse.core.runtime.Assert; import org.eclipse.core.runtime.IStatus; import org.eclipse.core.runtime.Status; /** * This is a helper that will hook up and listen for <code>PropertyChangeEvent</code> events * for a set of target JavaBeans * * @since 1.0 */ public class ListenerSupport { private Set elementsListenedTo = new HashSet(); private PropertyChangeListener listener; private String propertyName; /** * Constructs a new instance. * * @param listener is the callback that will be called * when a <code>PropertyChangeEvent</code> is fired on any * of the target objects. Will only receive change events * when the provided <code>propertyName</code> changes. * @param propertyName */ public this(final PropertyChangeListener listener, final String propertyName) { Assert.isNotNull(listener, "Listener cannot be null"); //$NON-NLS-1$ Assert.isNotNull(propertyName, "Property name cannot be null"); //$NON-NLS-1$ this.propertyName = propertyName; this.listener = new class() PropertyChangeListener { public void propertyChange(PropertyChangeEvent evt) { if (propertyName.equals(evt.getPropertyName())) { listener.propertyChange(evt); } } }; } /** * Start listen to target (if it supports the JavaBean property change listener pattern) * * @param target */ public void hookListener(Object target) { if (processListener( "addPropertyChangeListener", "Could not attach listener to ", target)) { //$NON-NLS-1$ //$NON-NLS-2$ elementsListenedTo.add(new IdentityWrapper(target)); } } /** * Add listeners for new targets (those this instance of<code>ListenerSupport</code> does not * already listen to), * Stop to listen to those object that this instance listen to and is one of the object in targets * * @param targets */ public void setHookTargets(Object[] targets) { Set elementsToUnhook = new HashSet(elementsListenedTo); if (targets!isnull) { for (int i = 0; i < targets.length; i++) { Object newValue = targets[i]; IdentityWrapper identityWrapper = new IdentityWrapper(newValue); if(!elementsToUnhook.remove(identityWrapper)) hookListener(newValue); } } for (Iterator it = elementsToUnhook.iterator(); it.hasNext();) { Object o = it.next(); if (o.getClass()!isIdentityWrapper.class) o = new IdentityWrapper(o); elementsListenedTo.remove(o); unhookListener(o); } } /** * Stop listen to target * * @param target */ public void unhookListener(Object target) { if (target.getClass() is IdentityWrapper.class) target = (cast(IdentityWrapper) target).unwrap(); if (processListener( "removePropertyChangeListener", "Cound not remove listener from ", target)) { //$NON-NLS-1$//$NON-NLS-2$ elementsListenedTo.remove(new IdentityWrapper(target)); } } /** * */ public void dispose() { if (elementsListenedTo!isnull) { Object[] targets = elementsListenedTo.toArray(); for (int i = 0; i < targets.length; i++) { unhookListener(targets[i]); } elementsListenedTo=null; listener=null; } } /** * @return elements that were registred to */ public Object[] getHookedTargets() { Object[] targets = null; if (elementsListenedTo!isnull && elementsListenedTo.size()>0) { Object[] identityList = elementsListenedTo.toArray(); targets = new Object[identityList.length]; for (int i = 0; i < identityList.length; i++) targets[i]=(cast(IdentityWrapper)identityList[i]).unwrap(); } return targets; } /** * Invokes the method for the provided <code>methodName</code> attempting * to first use the method with the property name and then the unnamed * version. * * @param methodName * either addPropertyChangeListener or * removePropertyChangeListener * @param message * string that will be prefixed to the target in an error message * @param target * object to invoke the method on * @return <code>true</code> if the method was invoked successfully */ private bool processListener(String methodName, String message, Object target) { Method method = null; Object[] parameters = null; try { try { method = target.getClass().getMethod( methodName, new Class[] { String.class, PropertyChangeListener.class }); parameters = new Object[] { propertyName, listener }; } catch (NoSuchMethodException e) { method = target.getClass().getMethod(methodName, new Class[] { PropertyChangeListener.class }); parameters = new Object[] { listener }; } } catch (SecurityException e) { // ignore } catch (NoSuchMethodException e) { log(IStatus.WARNING, message + target, e); } if (method !is null) { if (!method.isAccessible()) { method.setAccessible(true); } try { method.invoke(target, parameters); return true; } catch (IllegalArgumentException e) { log(IStatus.WARNING, message + target, e); } catch (IllegalAccessException e) { log(IStatus.WARNING, message + target, e); } catch (InvocationTargetException e) { log(IStatus.WARNING, message + target, e); } } return false; } /** * Logs a message to the Data Binding logger. */ private void log(int severity, String message, Throwable throwable) { if cast(BeansObservables.DEBUG) { Policy.getLog().log( new Status(severity, Policy.JFACE_DATABINDING, IStatus.OK, message, throwable)); } } }