1 /* 2 * Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package com.sun.java.accessibility.util; 27 28 import java.util.*; 29 import java.beans.*; 30 import java.awt.*; 31 import java.awt.event.*; 32 import javax.accessibility.*; 33 34 /** 35 * <P>The {@code AccessibilityListenerList} is a copy of the Swing 36 * {@link javax.swing.event.EventListenerList EventListerList} class. 37 * 38 */ 39 40 @jdk.Exported 41 public class AccessibilityListenerList { 42 /* A null array to be shared by all empty listener lists */ 43 private final static Object[] NULL_ARRAY = new Object[0]; 44 45 /** 46 * The list of listener type, listener pairs 47 */ 48 protected transient Object[] listenerList = NULL_ARRAY; 49 50 /** 51 * Passes back the event listener list as an array of listener type, listener pairs. 52 * Note that for performance reasons, this implementation passes back the actual 53 * data structure in which the listener data is stored internally. This method 54 * is guaranteed to pass back a non-null array, so that no null-checking 55 * is required in fire methods. A zero-length array of Object is returned if 56 * there are currently no listeners. 57 * <p> 58 * Absolutely no modification of the data contained in this array should be 59 * made. If any such manipulation is necessary, it should be done on a copy 60 * of the array returned rather than the array itself. 61 * 62 * @return an array of listener type, listener pairs. 63 */ 64 public Object[] getListenerList() { 65 return listenerList; 66 } 67 68 /** 69 * Returns the total number of listeners for this listener list. 70 * 71 * @return the total number of listeners for this listener list. 72 */ 73 public int getListenerCount() { 74 return listenerList.length/2; 75 } 76 77 /** 78 * Return the total number of listeners of the supplied type 79 * for this listener list. 80 * 81 * @param t the type of the listener to be counted 82 * @return the number of listeners found 83 */ 84 public int getListenerCount(Class t) { 85 int count = 0; 86 Object[] lList = listenerList; 87 for (int i = 0; i < lList.length; i+=2) { 88 if (t == (Class)lList[i]) 89 count++; 90 } 91 return count; 92 } 93 94 /** 95 * Add the listener as a listener of the specified type. 96 * 97 * @param t the type of the listener to be added 98 * @param l the listener to be added 99 */ 100 public synchronized void add(Class t, EventListener l) { 101 if (!t.isInstance(l)) { 102 throw new IllegalArgumentException("Listener " + l + 103 " is not of type " + t); 104 } 105 if (l ==null) { 106 throw new IllegalArgumentException("Listener " + l + 107 " is null"); 108 } 109 if (listenerList == NULL_ARRAY) { 110 // if this is the first listener added, 111 // initialize the lists 112 listenerList = new Object[] { t, l }; 113 } else { 114 // Otherwise copy the array and add the new listener 115 int i = listenerList.length; 116 Object[] tmp = new Object[i+2]; 117 System.arraycopy(listenerList, 0, tmp, 0, i); 118 119 tmp[i] = t; 120 tmp[i+1] = l; 121 122 listenerList = tmp; 123 } 124 } 125 126 /** 127 * Remove the listener as a listener of the specified type. 128 * 129 * @param t the type of the listener to be removed 130 * @param l the listener to be removed 131 */ 132 public synchronized void remove(Class t, EventListener l) { 133 if (!t.isInstance(l)) { 134 throw new IllegalArgumentException("Listener " + l + 135 " is not of type " + t); 136 } 137 if (l ==null) { 138 throw new IllegalArgumentException("Listener " + l + 139 " is null"); 140 } 141 142 // Is l on the list? 143 int index = -1; 144 for (int i = listenerList.length-2; i>=0; i-=2) { 145 if ((listenerList[i]==t) && (listenerList[i+1] == l)) { 146 index = i; 147 break; 148 } 149 } 150 151 // If so, remove it 152 if (index != -1) { 153 Object[] tmp = new Object[listenerList.length-2]; 154 // Copy the list up to index 155 System.arraycopy(listenerList, 0, tmp, 0, index); 156 // Copy from two past the index, up to 157 // the end of tmp (which is two elements 158 // shorter than the old list) 159 if (index < tmp.length) 160 System.arraycopy(listenerList, index+2, tmp, index, 161 tmp.length - index); 162 // set the listener array to the new array or null 163 listenerList = (tmp.length == 0) ? NULL_ARRAY : tmp; 164 } 165 } 166 167 /** 168 * Return a string representation of the {@code AccessibilityListenerList}. 169 * 170 * @return a string representation of the {@code AccessibilityListenerList}. 171 */ 172 public String toString() { 173 Object[] lList = listenerList; 174 String s = "EventListenerList: "; 175 s += lList.length/2 + " listeners: "; 176 for (int i = 0 ; i <= lList.length-2 ; i+=2) { 177 s += " type " + ((Class)lList[i]).getName(); 178 s += " listener " + lList[i+1]; 179 } 180 return s; 181 } 182 }