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 }