| /* |
| * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| package java.beans; |
| |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.EventListener; |
| import java.util.EventListenerProxy; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Map.Entry; |
| import java.util.Set; |
| |
| /** |
| * This is an abstract class that provides base functionality |
| * for the {@link PropertyChangeSupport PropertyChangeSupport} class |
| * and the {@link VetoableChangeSupport VetoableChangeSupport} class. |
| * |
| * @see PropertyChangeListenerMap |
| * @see VetoableChangeListenerMap |
| * |
| * @author Sergey A. Malenkov |
| */ |
| abstract class ChangeListenerMap<L extends EventListener> { |
| private Map<String, L[]> map; |
| |
| /** |
| * Creates an array of listeners. |
| * This method can be optimized by using |
| * the same instance of the empty array |
| * when {@code length} is equal to {@code 0}. |
| * |
| * @param length the array length |
| * @return an array with specified length |
| */ |
| protected abstract L[] newArray(int length); |
| |
| /** |
| * Creates a proxy listener for the specified property. |
| * |
| * @param name the name of the property to listen on |
| * @param listener the listener to process events |
| * @return a proxy listener |
| */ |
| protected abstract L newProxy(String name, L listener); |
| |
| /** |
| * Adds a listener to the list of listeners for the specified property. |
| * This listener is called as many times as it was added. |
| * |
| * @param name the name of the property to listen on |
| * @param listener the listener to process events |
| */ |
| public final synchronized void add(String name, L listener) { |
| if (this.map == null) { |
| this.map = new HashMap<>(); |
| } |
| L[] array = this.map.get(name); |
| int size = (array != null) |
| ? array.length |
| : 0; |
| |
| L[] clone = newArray(size + 1); |
| clone[size] = listener; |
| if (array != null) { |
| System.arraycopy(array, 0, clone, 0, size); |
| } |
| this.map.put(name, clone); |
| } |
| |
| /** |
| * Removes a listener from the list of listeners for the specified property. |
| * If the listener was added more than once to the same event source, |
| * this listener will be notified one less time after being removed. |
| * |
| * @param name the name of the property to listen on |
| * @param listener the listener to process events |
| */ |
| public final synchronized void remove(String name, L listener) { |
| if (this.map != null) { |
| L[] array = this.map.get(name); |
| if (array != null) { |
| for (int i = 0; i < array.length; i++) { |
| if (listener.equals(array[i])) { |
| int size = array.length - 1; |
| if (size > 0) { |
| L[] clone = newArray(size); |
| System.arraycopy(array, 0, clone, 0, i); |
| System.arraycopy(array, i + 1, clone, i, size - i); |
| this.map.put(name, clone); |
| } |
| else { |
| this.map.remove(name); |
| if (this.map.isEmpty()) { |
| this.map = null; |
| } |
| } |
| break; |
| } |
| } |
| } |
| } |
| } |
| |
| /** |
| * Returns the list of listeners for the specified property. |
| * |
| * @param name the name of the property |
| * @return the corresponding list of listeners |
| */ |
| public final synchronized L[] get(String name) { |
| return (this.map != null) |
| ? this.map.get(name) |
| : null; |
| } |
| |
| /** |
| * Sets new list of listeners for the specified property. |
| * |
| * @param name the name of the property |
| * @param listeners new list of listeners |
| */ |
| public final void set(String name, L[] listeners) { |
| if (listeners != null) { |
| if (this.map == null) { |
| this.map = new HashMap<>(); |
| } |
| this.map.put(name, listeners); |
| } |
| else if (this.map != null) { |
| this.map.remove(name); |
| if (this.map.isEmpty()) { |
| this.map = null; |
| } |
| } |
| } |
| |
| /** |
| * Returns all listeners in the map. |
| * |
| * @return an array of all listeners |
| */ |
| public final synchronized L[] getListeners() { |
| if (this.map == null) { |
| return newArray(0); |
| } |
| List<L> list = new ArrayList<>(); |
| |
| L[] listeners = this.map.get(null); |
| if (listeners != null) { |
| for (L listener : listeners) { |
| list.add(listener); |
| } |
| } |
| for (Entry<String, L[]> entry : this.map.entrySet()) { |
| String name = entry.getKey(); |
| if (name != null) { |
| for (L listener : entry.getValue()) { |
| list.add(newProxy(name, listener)); |
| } |
| } |
| } |
| return list.toArray(newArray(list.size())); |
| } |
| |
| /** |
| * Returns listeners that have been associated with the named property. |
| * |
| * @param name the name of the property |
| * @return an array of listeners for the named property |
| */ |
| public final L[] getListeners(String name) { |
| if (name != null) { |
| L[] listeners = get(name); |
| if (listeners != null) { |
| return listeners.clone(); |
| } |
| } |
| return newArray(0); |
| } |
| |
| /** |
| * Indicates whether the map contains |
| * at least one listener to be notified. |
| * |
| * @param name the name of the property |
| * @return {@code true} if at least one listener exists or |
| * {@code false} otherwise |
| */ |
| public final synchronized boolean hasListeners(String name) { |
| if (this.map == null) { |
| return false; |
| } |
| L[] array = this.map.get(null); |
| return (array != null) || ((name != null) && (null != this.map.get(name))); |
| } |
| |
| /** |
| * Returns a set of entries from the map. |
| * Each entry is a pair consisted of the property name |
| * and the corresponding list of listeners. |
| * |
| * @return a set of entries from the map |
| */ |
| public final Set<Entry<String, L[]>> getEntries() { |
| return (this.map != null) |
| ? this.map.entrySet() |
| : Collections.<Entry<String, L[]>>emptySet(); |
| } |
| |
| /** |
| * Extracts a real listener from the proxy listener. |
| * It is necessary because default proxy class is not serializable. |
| * |
| * @return a real listener |
| */ |
| public abstract L extract(L listener); |
| } |