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package com.sun.media.sound;

import javax.sound.midi.MidiDevice;

MIDI output device provider.
Author:Kara Kytle, Florian Bomers
/** * MIDI output device provider. * * @author Kara Kytle * @author Florian Bomers */
public final class MidiOutDeviceProvider extends AbstractMidiDeviceProvider {
Cache of info objects for all MIDI output devices on the system.
/** Cache of info objects for all MIDI output devices on the system. */
private static Info[] infos = null;
Cache of open MIDI output devices on the system.
/** Cache of open MIDI output devices on the system. */
private static MidiDevice[] devices = null; private static final boolean enabled; static { // initialize Platform.initialize(); enabled = Platform.isMidiIOEnabled(); }
Required public no-arg constructor.
/** * Required public no-arg constructor. */
public MidiOutDeviceProvider() { if (Printer.trace) Printer.trace("MidiOutDeviceProvider: constructor"); } @Override AbstractMidiDeviceProvider.Info createInfo(int index) { if (!enabled) { return null; } return new MidiOutDeviceInfo(index, MidiOutDeviceProvider.class); } @Override MidiDevice createDevice(AbstractMidiDeviceProvider.Info info) { if (enabled && (info instanceof MidiOutDeviceInfo)) { return new MidiOutDevice(info); } return null; } @Override int getNumDevices() { if (!enabled) { if (Printer.debug)Printer.debug("MidiOutDevice not enabled, returning 0 devices"); return 0; } return nGetNumDevices(); } @Override MidiDevice[] getDeviceCache() { return devices; } @Override void setDeviceCache(MidiDevice[] devices) { MidiOutDeviceProvider.devices = devices; } @Override Info[] getInfoCache() { return infos; } @Override void setInfoCache(Info[] infos) { MidiOutDeviceProvider.infos = infos; }
Info class for MidiOutDevices. Adds the provider's Class to keep the provider class from being unloaded. Otherwise, at least on JDK1.1.7 and 1.1.8, the provider class can be unloaded. Then, then the provider is next invoked, the static block is executed again and a new instance of the device object is created. Even though the previous instance may still exist and be open / in use / etc., the new instance will not reflect that state...
/** * Info class for MidiOutDevices. Adds the * provider's Class to keep the provider class from being * unloaded. Otherwise, at least on JDK1.1.7 and 1.1.8, * the provider class can be unloaded. Then, then the provider * is next invoked, the static block is executed again and a new * instance of the device object is created. Even though the * previous instance may still exist and be open / in use / etc., * the new instance will not reflect that state... */
static final class MidiOutDeviceInfo extends AbstractMidiDeviceProvider.Info { private final Class<?> providerClass; private MidiOutDeviceInfo(int index, Class<?> providerClass) { super(nGetName(index), nGetVendor(index), nGetDescription(index), nGetVersion(index), index); this.providerClass = providerClass; } } // class MidiOutDeviceInfo private static native int nGetNumDevices(); private static native String nGetName(int index); private static native String nGetVendor(int index); private static native String nGetDescription(int index); private static native String nGetVersion(int index); }