MidiInDeviceProvider.java

/*
 * This file is modified by Ivan Maidanski <ivmai@ivmaisoft.com>
 * Project name: JCGO-SUNAWT (http://www.ivmaisoft.com/jcgo/)
 */

/*
 * @(#)MidiInDeviceProvider.java        1.12 03/01/23
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package com.sun.media.sound;

import javax.sound.midi.MidiDevice;
import javax.sound.midi.spi.MidiDeviceProvider;


/**
 * MIDI input device provider.
 *
 * @version 1.12, 03/01/23
 * @author Kara Kytle
 * @author Florian Bomers
 */
public class MidiInDeviceProvider extends AbstractMidiDeviceProvider {

    /** Cache of info objects for all MIDI output devices on the system. */
    static Info[] infos;

    /** Cache of open MIDI input devices on the system. */
    static MidiDevice[] devices;

    // CONSTRUCTOR

    /**
     * Required public no-arg constructor.
     */
    public MidiInDeviceProvider() {
        if (Printer.trace) Printer.trace("MidiInDeviceProvider: constructor");
    }

    // implementation of abstract methods in AbstractMidiDeviceProvider

    AbstractMidiDeviceProvider.Info createInfo(int index) {
        return new MidiInDeviceInfo(index, MidiInDeviceProvider.class);
    }

    MidiDevice createDevice(AbstractMidiDeviceProvider.Info info) {
        if (info instanceof MidiInDeviceInfo) {
            return new MidiInDevice(info);
        }
        return null;
    }

    int getNumDevices() { return nGetNumDevices(); }
    MidiDevice[] getDeviceCache() { return devices; }
    void setDeviceCache(MidiDevice[] devices) { this.devices = devices; }
    Info[] getInfoCache() { return infos; }
    void setInfoCache(Info[] infos) { this.infos = infos; }


    // INNER CLASSES

    /**
     * Info class for MidiInDevices.  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 class MidiInDeviceInfo extends AbstractMidiDeviceProvider.Info {
        private Class providerClass;

        private MidiInDeviceInfo(int index, Class providerClass) {
            super(nGetName(index), nGetVendor(index), nGetDescription(index), nGetVersion(index), index);
            this.providerClass = providerClass;
        }

    } // class MidiInDeviceInfo


    // NATIVE METHODS

    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);
}