1 /* 2 * Copyright (c) 2011, 2012, 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.tools.javac.api; 27 28 import java.util.Arrays; 29 import java.util.Collection; 30 31 import com.sun.source.util.TaskEvent; 32 import com.sun.source.util.TaskListener; 33 import com.sun.tools.javac.util.Context; 34 import com.sun.tools.javac.util.DefinedBy; 35 import com.sun.tools.javac.util.DefinedBy.Api; 36 37 /** 38 * A collection of currently registered {@link TaskListener}s. Events passed to this TaskListener 39 * will be forwarded to all the registered TaskListeners. 40 * 41 * <p><b>This is NOT part of any supported API. 42 * If you write code that depends on this, you do so at your own risk. 43 * This code and its internal interfaces are subject to change or 44 * deletion without notice.</b> 45 */ 46 public class MultiTaskListener implements TaskListener { 47 /** The context key for the MultiTaskListener. */ 48 public static final Context.Key<MultiTaskListener> taskListenerKey = new Context.Key<>(); 49 50 /** Empty array of task listeners */ 51 private static final TaskListener[] EMPTY_LISTENERS = new TaskListener[0]; 52 53 /** Get the MultiTaskListener instance for this context. */ 54 public static MultiTaskListener instance(Context context) { 55 MultiTaskListener instance = context.get(taskListenerKey); 56 if (instance == null) 57 instance = new MultiTaskListener(context); 58 return instance; 59 } 60 61 protected MultiTaskListener(Context context) { 62 context.put(taskListenerKey, this); 63 ccw = ClientCodeWrapper.instance(context); 64 } 65 66 /** 67 * The current set of registered listeners. 68 * This is a mutable reference to an immutable array. 69 */ 70 TaskListener[] listeners = EMPTY_LISTENERS; 71 72 ClientCodeWrapper ccw; 73 74 public Collection<TaskListener> getTaskListeners() { 75 return Arrays.asList(listeners); 76 } 77 78 public boolean isEmpty() { 79 return listeners == EMPTY_LISTENERS; 80 } 81 82 public void add(TaskListener listener) { 83 for (TaskListener l: listeners) { 84 if (ccw.unwrap(l) == listener) 85 throw new IllegalStateException(); 86 } 87 listeners = Arrays.copyOf(listeners, listeners.length + 1); 88 listeners[listeners.length - 1] = ccw.wrap(listener); 89 } 90 91 public void remove(TaskListener listener) { 92 for (int i = 0; i < listeners.length; i++) { 93 if (ccw.unwrap(listeners[i]) == listener) { 94 if (listeners.length == 1) { 95 listeners = EMPTY_LISTENERS; 96 } else { 97 TaskListener[] newListeners = new TaskListener[listeners.length - 1]; 98 System.arraycopy(listeners, 0, newListeners, 0, i); 99 System.arraycopy(listeners, i + 1, newListeners, i, newListeners.length - i); 100 listeners = newListeners; 101 } 102 break; 103 } 104 } 105 } 106 107 @Override @DefinedBy(Api.COMPILER_TREE) 108 public void started(TaskEvent e) { 109 // guard against listeners being updated by a listener 110 TaskListener[] ll = this.listeners; 111 for (TaskListener l: ll) 112 l.started(e); 113 } 114 115 @Override @DefinedBy(Api.COMPILER_TREE) 116 public void finished(TaskEvent e) { 117 // guard against listeners being updated by a listener 118 TaskListener[] ll = this.listeners; 119 for (TaskListener l: ll) 120 l.finished(e); 121 } 122 123 @Override 124 public String toString() { 125 return Arrays.toString(listeners); 126 } 127 128 public void clear() { 129 listeners = EMPTY_LISTENERS; 130 } 131 }