| /******************************************************************************* |
| * Copyright (c) 2004, 2006 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 |
| *******************************************************************************/ |
| package org.eclipse.ui.internal.preferences; |
| |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.HashSet; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Map; |
| |
| /** |
| * @since 3.1 |
| */ |
| public final class PropertyListenerList { |
| private Map listeners; |
| private List globalListeners; |
| private static String[] singlePropertyDelta; |
| private static Object mutex = new Object(); |
| |
| public PropertyListenerList() { |
| } |
| |
| public void firePropertyChange(String prefId) { |
| String[] delta; |
| |
| // Optimization: as long as we're not being called recursively, |
| // we can reuse the same delta object to avoid repeated memory |
| // allocation. |
| synchronized(mutex) { |
| if (singlePropertyDelta != null) { |
| delta = singlePropertyDelta; |
| singlePropertyDelta = null; |
| } else { |
| delta = new String[] {prefId}; |
| } |
| } |
| |
| delta[0] = prefId; |
| |
| firePropertyChange(delta); |
| |
| // Optimization: allow this same delta object to be reused at a later |
| // time |
| if (singlePropertyDelta == null) { |
| synchronized(mutex) { |
| singlePropertyDelta = delta; |
| } |
| } |
| } |
| |
| public void firePropertyChange(String[] propertyIds) { |
| if (globalListeners != null) { |
| for (Iterator iter = globalListeners.iterator(); iter.hasNext();) { |
| IPropertyMapListener next = (IPropertyMapListener) iter.next(); |
| |
| next.propertyChanged(propertyIds); |
| } |
| } |
| |
| if (listeners != null) { |
| |
| // To avoid temporary memory allocation, we try to simply move the |
| // result pointer around if possible. We only allocate a HashSet |
| // to compute which listeners we care about |
| Collection result = Collections.EMPTY_SET; |
| HashSet union = null; |
| |
| for (int i = 0; i < propertyIds.length; i++) { |
| String property = propertyIds[i]; |
| |
| List existingListeners = (List)listeners.get(property); |
| |
| if (existingListeners != null) { |
| if (result == Collections.EMPTY_SET) { |
| result = existingListeners; |
| } else { |
| if (union == null) { |
| union = new HashSet(); |
| union.addAll(result); |
| result = union; |
| } |
| |
| union.addAll(existingListeners); |
| } |
| } |
| } |
| |
| for (Iterator iter = result.iterator(); iter.hasNext();) { |
| IPropertyMapListener next = (IPropertyMapListener) iter.next(); |
| |
| next.propertyChanged(propertyIds); |
| } |
| } |
| } |
| |
| public void add(IPropertyMapListener newListener) { |
| if (globalListeners == null) { |
| globalListeners = new ArrayList(); |
| } |
| |
| globalListeners.add(newListener); |
| newListener.listenerAttached(); |
| } |
| |
| /** |
| * Adds a listener which will be notified when the given property changes |
| * |
| * @param propertyId |
| * @param newListener |
| * @since 3.1 |
| */ |
| private void addInternal(String propertyId, IPropertyMapListener newListener) { |
| if (listeners == null) { |
| listeners = new HashMap(); |
| } |
| |
| List listenerList = (List)listeners.get(propertyId); |
| |
| if (listenerList == null) { |
| listenerList = new ArrayList(1); |
| listeners.put(propertyId, listenerList); |
| } |
| |
| if (!listenerList.contains(newListener)) { |
| listenerList.add(newListener); |
| } |
| } |
| |
| public void add(String[] propertyIds, IPropertyMapListener newListener) { |
| for (int i = 0; i < propertyIds.length; i++) { |
| String id = propertyIds[i]; |
| |
| addInternal(id, newListener); |
| } |
| newListener.listenerAttached(); |
| } |
| |
| public void remove(String propertyId, IPropertyMapListener toRemove) { |
| if (listeners == null) { |
| return; |
| } |
| List listenerList = (List)listeners.get(propertyId); |
| |
| if (listenerList != null) { |
| listenerList.remove(toRemove); |
| |
| if (listenerList.isEmpty()) { |
| listeners.remove(propertyId); |
| |
| if (listeners.isEmpty()) { |
| listeners = null; |
| } |
| } |
| } |
| } |
| |
| public void removeAll() { |
| globalListeners = null; |
| listeners = null; |
| } |
| |
| public void remove(IPropertyMapListener toRemove) { |
| if (globalListeners != null) { |
| globalListeners.remove(toRemove); |
| if (globalListeners.isEmpty()) { |
| globalListeners = null; |
| } |
| } |
| |
| if (listeners != null) { |
| for (Iterator iter = listeners.keySet().iterator(); iter.hasNext();) { |
| String key = (String) iter.next(); |
| |
| remove(key, toRemove); |
| } |
| } |
| } |
| |
| public boolean isEmpty() { |
| return globalListeners == null && listeners == null; |
| } |
| } |