/*

 * Copyright (c) 2011, 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 com.sun.tools.javac.api;

import java.util.Arrays;

import java.util.Collection;

import com.sun.source.util.TaskEvent;

import com.sun.source.util.TaskListener;

import com.sun.tools.javac.util.Context;

import com.sun.tools.javac.util.DefinedBy;

import com.sun.tools.javac.util.DefinedBy.Api;

/**

 * A collection of currently registered {@link TaskListener}s. Events passed to this TaskListener

 * will be forwarded to all the registered TaskListeners.

 *

 * <p><b>This is NOT part of any supported API.

 * If you write code that depends on this, you do so at your own risk.

 * This code and its internal interfaces are subject to change or

 * deletion without notice.</b>

 */

public class MultiTaskListener implements TaskListener {

    /** The context key for the MultiTaskListener. */

    public static final Context.Key<MultiTaskListener> taskListenerKey = new Context.Key<>();

    /** Get the MultiTaskListener instance for this context. */

    public static MultiTaskListener instance(Context context) {

        MultiTaskListener instance = context.get(taskListenerKey);

        if (instance == null)

            instance = new MultiTaskListener(context);

        return instance;

    }

    protected MultiTaskListener(Context context) {

        context.put(taskListenerKey, this);

        ccw = ClientCodeWrapper.instance(context);

    }

    /**

     * The current set of registered listeners.

     * This is a mutable reference to an immutable array.

     */

    ClientCodeWrapper ccw;

    public Collection<TaskListener> getTaskListeners() {

        return Arrays.asList(listeners);

    }

    public boolean isEmpty() {

    }

    public void add(TaskListener listener) {

        for (TaskListener l: listeners) {

            if (ccw.unwrap(l) == listener)

                throw new IllegalStateException();

        }

        listeners = Arrays.copyOf(listeners, listeners.length + 1);

        listeners[listeners.length - 1] = ccw.wrap(listener);

    }

    public void remove(TaskListener listener) {

        for (int i = 0; i < listeners.length; i++) {

            if (ccw.unwrap(listeners[i]) == listener) {

                break;

            }

        }

    }

    @Override @DefinedBy(Api.COMPILER_TREE)

    public void started(TaskEvent e) {

        // guard against listeners being updated by a listener

        TaskListener[] ll = this.listeners;

        for (TaskListener l: ll)

            l.started(e);

    }

    @Override @DefinedBy(Api.COMPILER_TREE)

    public void finished(TaskEvent e) {

        // guard against listeners being updated by a listener

        TaskListener[] ll = this.listeners;

        for (TaskListener l: ll)

            l.finished(e);

    }

    @Override

    public String toString() {

        return Arrays.toString(listeners);

    }

}