/*
 * Copyright (c) 1998, 2018, 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.media.sound;

import java.util.ArrayList;
import java.util.List;

import javax.sound.midi.ControllerEventListener;
import javax.sound.midi.MetaEventListener;
import javax.sound.midi.MetaMessage;
import javax.sound.midi.ShortMessage;
import javax.sound.sampled.LineEvent;
import javax.sound.sampled.LineListener;



EventDispatcher.  Used by various classes in the Java Sound implementation
to send events.
Author:
David Rivas, Kara Kytle, Florian Bomers/**
 * EventDispatcher.  Used by various classes in the Java Sound implementation
 * to send events.
 *
 * @author David Rivas
 * @author Kara Kytle
 * @author Florian Bomers
 */
final class EventDispatcher implements Runnable {

    
time of inactivity until the auto closing clips
are closed
/**
     * time of inactivity until the auto closing clips
     * are closed
     */
    private static final int AUTO_CLOSE_TIME = 5000;


    
List of events
/**
     * List of events
     */
    private final ArrayList eventQueue = new ArrayList();


    
Thread object for this EventDispatcher instance
/**
     * Thread object for this EventDispatcher instance
     */
    private Thread thread = null;


    /*
     * support for auto-closing Clips
     */
    private final ArrayList<ClipInfo> autoClosingClips = new ArrayList<ClipInfo>();

    /*
     * support for monitoring data lines
     */
    private final ArrayList<LineMonitor> lineMonitors = new ArrayList<LineMonitor>();

    
Approximate interval between calls to LineMonitor.checkLine
/**
     * Approximate interval between calls to LineMonitor.checkLine
     */
    static final int LINE_MONITOR_TIME = 400;


    
This start() method starts an event thread if one is not already active.
/**
     * This start() method starts an event thread if one is not already active.
     */
    synchronized void start() {

        if(thread == null) {
            thread = JSSecurityManager.createThread(this,
                                                    "Java Sound Event Dispatcher",   // name
                                                    true,  // daemon
                                                    -1,    // priority
                                                    true); // doStart
        }
    }


    
Invoked when there is at least one event in the queue.
Implement this as a callback to process one event.
/**
     * Invoked when there is at least one event in the queue.
     * Implement this as a callback to process one event.
     */
    void processEvent(EventInfo eventInfo) {
        int count = eventInfo.getListenerCount();

        // process an LineEvent
        if (eventInfo.getEvent() instanceof LineEvent) {
            LineEvent event = (LineEvent) eventInfo.getEvent();
            if (Printer.debug) Printer.debug("Sending "+event+" to "+count+" listeners");
            for (int i = 0; i < count; i++) {
                try {
                    ((LineListener) eventInfo.getListener(i)).update(event);
                } catch (Throwable t) {
                    if (Printer.err) t.printStackTrace();
                }
            }
            return;
        }

        // process a MetaMessage
        if (eventInfo.getEvent() instanceof MetaMessage) {
            MetaMessage event = (MetaMessage)eventInfo.getEvent();
            for (int i = 0; i < count; i++) {
                try {
                    ((MetaEventListener) eventInfo.getListener(i)).meta(event);
                } catch (Throwable t) {
                    if (Printer.err) t.printStackTrace();
                }
            }
            return;
        }

        // process a Controller or Mode Event
        if (eventInfo.getEvent() instanceof ShortMessage) {
            ShortMessage event = (ShortMessage)eventInfo.getEvent();
            int status = event.getStatus();

            // Controller and Mode events have status byte 0xBc, where
            // c is the channel they are sent on.
            if ((status & 0xF0) == 0xB0) {
                for (int i = 0; i < count; i++) {
                    try {
                        ((ControllerEventListener) eventInfo.getListener(i)).controlChange(event);
                    } catch (Throwable t) {
                        if (Printer.err) t.printStackTrace();
                    }
                }
            }
            return;
        }

        Printer.err("Unknown event type: " + eventInfo.getEvent());
    }


    
Wait until there is something in the event queue to process.  Then
dispatch the event to the listeners.The entire method does not
need to be synchronized since this includes taking the event out
from the queue and processing the event. We only need to provide
exclusive access over the code where an event is removed from the
queue.
/**
     * Wait until there is something in the event queue to process.  Then
     * dispatch the event to the listeners.The entire method does not
     * need to be synchronized since this includes taking the event out
     * from the queue and processing the event. We only need to provide
     * exclusive access over the code where an event is removed from the
     *queue.
     */
    void dispatchEvents() {

        EventInfo eventInfo = null;

        synchronized (this) {

            // Wait till there is an event in the event queue.
            try {

                if (eventQueue.size() == 0) {
                    if (autoClosingClips.size() > 0 || lineMonitors.size() > 0) {
                        int waitTime = AUTO_CLOSE_TIME;
                        if (lineMonitors.size() > 0) {
                            waitTime = LINE_MONITOR_TIME;
                        }
                        wait(waitTime);
                    } else {
                        wait();
                    }
                }
            } catch (InterruptedException e) {
            }
            if (eventQueue.size() > 0) {
                // Remove the event from the queue and dispatch it to the listeners.
                eventInfo = (EventInfo) eventQueue.remove(0);
            }

        } // end of synchronized
        if (eventInfo != null) {
            processEvent(eventInfo);
        } else {
            if (autoClosingClips.size() > 0) {
                closeAutoClosingClips();
            }
            if (lineMonitors.size() > 0) {
                monitorLines();
            }
        }
    }


    
Queue the given event in the event queue.
/**
     * Queue the given event in the event queue.
     */
    private synchronized void postEvent(EventInfo eventInfo) {
        eventQueue.add(eventInfo);
        notifyAll();
    }


    
A loop to dispatch events.
/**
     * A loop to dispatch events.
     */
    public void run() {

        while (true) {
            try {
                dispatchEvents();
            } catch (Throwable t) {
                if (Printer.err) t.printStackTrace();
            }
        }
    }


    
Send audio and MIDI events.
/**
     * Send audio and MIDI events.
     */
    void sendAudioEvents(Object event, List listeners) {
        if ((listeners == null)
            || (listeners.size() == 0)) {
            // nothing to do
            return;
        }

        start();

        EventInfo eventInfo = new EventInfo(event, listeners);
        postEvent(eventInfo);
    }


    /*
     * go through the list of registered auto-closing
     * Clip instances and close them, if appropriate
     *
     * This method is called in regular intervals
     */
    private void closeAutoClosingClips() {
        synchronized(autoClosingClips) {
            if (Printer.debug)Printer.debug("> EventDispatcher.closeAutoClosingClips ("+autoClosingClips.size()+" clips)");
            long currTime = System.currentTimeMillis();
            for (int i = autoClosingClips.size()-1; i >= 0 ; i--) {
                ClipInfo info = autoClosingClips.get(i);
                if (info.isExpired(currTime)) {
                    AutoClosingClip clip = info.getClip();
                    // sanity check
                    if (!clip.isOpen() || !clip.isAutoClosing()) {
                        if (Printer.debug)Printer.debug("EventDispatcher: removing clip "+clip+"  isOpen:"+clip.isOpen());
                        autoClosingClips.remove(i);
                    }
                    else if (!clip.isRunning() && !clip.isActive() && clip.isAutoClosing()) {
                        if (Printer.debug)Printer.debug("EventDispatcher: closing clip "+clip);
                        clip.close();
                    } else {
                        if (Printer.debug)Printer.debug("Doing nothing with clip "+clip+":");
                        if (Printer.debug)Printer.debug("  open="+clip.isOpen()+", autoclosing="+clip.isAutoClosing());
                        if (Printer.debug)Printer.debug("  isRunning="+clip.isRunning()+", isActive="+clip.isActive());
                    }
                } else {
                    if (Printer.debug)Printer.debug("EventDispatcher: clip "+info.getClip()+" not yet expired");
                }
            }
        }
        if (Printer.debug)Printer.debug("< EventDispatcher.closeAutoClosingClips ("+autoClosingClips.size()+" clips)");
    }

    private int getAutoClosingClipIndex(AutoClosingClip clip) {
        synchronized(autoClosingClips) {
            for (int i = autoClosingClips.size()-1; i >= 0; i--) {
                if (clip.equals(autoClosingClips.get(i).getClip())) {
                    return i;
                }
            }
        }
        return -1;
    }

    
called from auto-closing clips when one of their open() method is called
/**
     * called from auto-closing clips when one of their open() method is called
     */
    void autoClosingClipOpened(AutoClosingClip clip) {
        if (Printer.debug)Printer.debug("> EventDispatcher.autoClosingClipOpened ");
        int index = 0;
        synchronized(autoClosingClips) {
            index = getAutoClosingClipIndex(clip);
            if (index == -1) {
                if (Printer.debug)Printer.debug("EventDispatcher: adding auto-closing clip "+clip);
                autoClosingClips.add(new ClipInfo(clip));
            }
        }
        if (index == -1) {
            synchronized (this) {
                // this is only for the case that the first clip is set to autoclosing,
                // and it is already open, and nothing is done with it.
                // EventDispatcher.process() method would block in wait() and
                // never close this first clip, keeping the device open.
                notifyAll();
            }
        }
        if (Printer.debug)Printer.debug("< EventDispatcher.autoClosingClipOpened finished("+autoClosingClips.size()+" clips)");
    }

    
called from auto-closing clips when their closed() method is called
/**
     * called from auto-closing clips when their closed() method is called
     */
    void autoClosingClipClosed(AutoClosingClip clip) {
        synchronized(autoClosingClips) {
            int index = getAutoClosingClipIndex(clip);
            if (index != -1) {
                autoClosingClips.remove(index);
            }
        }
    }


    // ////////////////////////// Line Monitoring Support /////////////////// //
    /*
     * go through the list of registered line monitors
     * and call their checkLine method
     *
     * This method is called in regular intervals
     */
    private void monitorLines() {
        synchronized(lineMonitors) {
            if (Printer.debug)Printer.debug("> EventDispatcher.monitorLines ("+lineMonitors.size()+" monitors)");
            for (int i = 0; i < lineMonitors.size(); i++) {
                lineMonitors.get(i).checkLine();
            }
        }
        if (Printer.debug)Printer.debug("< EventDispatcher.monitorLines("+lineMonitors.size()+" monitors)");
    }


    
Add this LineMonitor instance to the list of monitors
/**
     * Add this LineMonitor instance to the list of monitors
     */
    void addLineMonitor(LineMonitor lm) {
        if (Printer.trace)Printer.trace("> EventDispatcher.addLineMonitor("+lm+")");
        synchronized(lineMonitors) {
            if (lineMonitors.indexOf(lm) >= 0) {
                if (Printer.trace)Printer.trace("< EventDispatcher.addLineMonitor finished -- this monitor already exists!");
                return;
            }
            if (Printer.debug)Printer.debug("EventDispatcher: adding line monitor "+lm);
            lineMonitors.add(lm);
        }
        synchronized (this) {
            // need to interrupt the infinite wait()
            notifyAll();
        }
        if (Printer.debug)Printer.debug("< EventDispatcher.addLineMonitor finished -- now ("+lineMonitors.size()+" monitors)");
    }

    
Remove this LineMonitor instance from the list of monitors
/**
     * Remove this LineMonitor instance from the list of monitors
     */
    void removeLineMonitor(LineMonitor lm) {
        if (Printer.trace)Printer.trace("> EventDispatcher.removeLineMonitor("+lm+")");
        synchronized(lineMonitors) {
            if (lineMonitors.indexOf(lm) < 0) {
                if (Printer.trace)Printer.trace("< EventDispatcher.removeLineMonitor finished -- this monitor does not exist!");
                return;
            }
            if (Printer.debug)Printer.debug("EventDispatcher: removing line monitor "+lm);
            lineMonitors.remove(lm);
        }
        if (Printer.debug)Printer.debug("< EventDispatcher.removeLineMonitor finished -- now ("+lineMonitors.size()+" monitors)");
    }

    // /////////////////////////////////// INNER CLASSES ////////////////////////////////////////// //

    
Container for an event and a set of listeners to deliver it to.
/**
     * Container for an event and a set of listeners to deliver it to.
     */
    private class EventInfo {

        private final Object event;
        private final Object[] listeners;

        
Create a new instance of this event Info class
Params:
event – the event to be dispatched
listeners – listener list; will be copied/**
         * Create a new instance of this event Info class
         * @param event the event to be dispatched
         * @param listeners listener list; will be copied
         */
        EventInfo(Object event, List listeners) {
            this.event = event;
            this.listeners = listeners.toArray();
        }

        Object getEvent() {
            return event;
        }

        int getListenerCount() {
            return listeners.length;
        }

        Object getListener(int index) {
            return listeners[index];
        }

    } // class EventInfo


    
Container for a clip with its expiration time
/**
     * Container for a clip with its expiration time
     */
    private class ClipInfo {

        private final AutoClosingClip clip;
        private final long expiration;

        
Create a new instance of this clip Info class
/**
         * Create a new instance of this clip Info class
         */
        ClipInfo(AutoClosingClip clip) {
            this.clip = clip;
            this.expiration = System.currentTimeMillis() + AUTO_CLOSE_TIME;
        }

        AutoClosingClip getClip() {
            return clip;
        }

        boolean isExpired(long currTime) {
            return currTime > expiration;
        }
    } // class ClipInfo


    
Interface that a class that wants to get regular
line monitor events implements
/**
     * Interface that a class that wants to get regular
     * line monitor events implements
     */
    interface LineMonitor {
        
Called by event dispatcher in regular intervals
/**
         * Called by event dispatcher in regular intervals
         */
        public void checkLine();
    }

} // class EventDispatcher