1 /*
   2  * Copyright (c) 1999, 2014, 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.media.sound;
  27 
  28 import javax.sound.midi.MidiDevice;
  29 
  30 
  31 /**
  32  * MIDI output device provider.
  33  *
  34  * @author Kara Kytle
  35  * @author Florian Bomers
  36  */
  37 public final class MidiOutDeviceProvider extends AbstractMidiDeviceProvider {
  38 
  39     /** Cache of info objects for all MIDI output devices on the system. */
  40     private static Info[] infos = null;
  41 
  42     /** Cache of open MIDI output devices on the system. */
  43     private static MidiDevice[] devices = null;
  44 
  45     private final static boolean enabled;
  46 
  47     // STATIC
  48 
  49     static {
  50         // initialize
  51         Platform.initialize();
  52         enabled = Platform.isMidiIOEnabled();
  53     }
  54 
  55     // CONSTRUCTOR
  56 
  57     /**
  58      * Required public no-arg constructor.
  59      */
  60     public MidiOutDeviceProvider() {
  61         if (Printer.trace) Printer.trace("MidiOutDeviceProvider: constructor");
  62     }
  63 
  64     // implementation of abstract methods in AbstractMidiDeviceProvider
  65 
  66     AbstractMidiDeviceProvider.Info createInfo(int index) {
  67         if (!enabled) {
  68             return null;
  69         }
  70         return new MidiOutDeviceInfo(index, MidiOutDeviceProvider.class);
  71     }
  72 
  73     MidiDevice createDevice(AbstractMidiDeviceProvider.Info info) {
  74         if (enabled && (info instanceof MidiOutDeviceInfo)) {
  75             return new MidiOutDevice(info);
  76         }
  77         return null;
  78     }
  79 
  80     int getNumDevices() {
  81         if (!enabled) {
  82             if (Printer.debug)Printer.debug("MidiOutDevice not enabled, returning 0 devices");
  83             return 0;
  84         }
  85         return nGetNumDevices();
  86     }
  87 
  88     MidiDevice[] getDeviceCache() { return devices; }
  89     void setDeviceCache(MidiDevice[] devices) { MidiOutDeviceProvider.devices = devices; }
  90     Info[] getInfoCache() { return infos; }
  91     void setInfoCache(Info[] infos) { MidiOutDeviceProvider.infos = infos; }
  92 
  93 
  94     // INNER CLASSES
  95 
  96     /**
  97      * Info class for MidiOutDevices.  Adds the
  98      * provider's Class to keep the provider class from being
  99      * unloaded.  Otherwise, at least on JDK1.1.7 and 1.1.8,
 100      * the provider class can be unloaded.  Then, then the provider
 101      * is next invoked, the static block is executed again and a new
 102      * instance of the device object is created.  Even though the
 103      * previous instance may still exist and be open / in use / etc.,
 104      * the new instance will not reflect that state...
 105      */
 106     static final class MidiOutDeviceInfo extends AbstractMidiDeviceProvider.Info {
 107         private final Class providerClass;
 108 
 109         private MidiOutDeviceInfo(int index, Class providerClass) {
 110             super(nGetName(index), nGetVendor(index), nGetDescription(index), nGetVersion(index), index);
 111             this.providerClass = providerClass;
 112         }
 113 
 114     } // class MidiOutDeviceInfo
 115 
 116 
 117     // NATIVE METHODS
 118 
 119     private static native int nGetNumDevices();
 120     private static native String nGetName(int index);
 121     private static native String nGetVendor(int index);
 122     private static native String nGetDescription(int index);
 123     private static native String nGetVersion(int index);
 124 }