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/* * Copyright (c) 1999, 2017, 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 javax.sound.midi; import java.util.List; /** * {@code MidiDevice} is the base interface for all MIDI devices. Common devices * include synthesizers, sequencers, MIDI input ports, and MIDI output ports. * <p> * A {@code MidiDevice} can be a transmitter or a receiver of MIDI events, or * both. Therefore, it can provide {@link Transmitter} or {@link Receiver} * instances (or both). Typically, MIDI IN ports provide transmitters, MIDI OUT * ports and synthesizers provide receivers. A Sequencer typically provides * transmitters for playback and receivers for recording. * <p> * A {@code MidiDevice} can be opened and closed explicitly as well as * implicitly. Explicit opening is accomplished by calling {@link #open}, * explicit closing is done by calling {@link #close} on the {@code MidiDevice} * instance. If an application opens a {@code MidiDevice} explicitly, it has to * close it explicitly to free system resources and enable the application to * exit cleanly. Implicit opening is done by calling * {@link MidiSystem#getReceiver} and {@link MidiSystem#getTransmitter}. The * {@code MidiDevice} used by {@code MidiSystem.getReceiver} and * {@code MidiSystem.getTransmitter} is implementation-dependent unless the * properties {@code javax.sound.midi.Receiver} and * {@code javax.sound.midi.Transmitter} are used (see the description of * properties to select default providers in {@link MidiSystem}). A * {@code MidiDevice} that was opened implicitly, is closed implicitly by * closing the {@code Receiver} or {@code Transmitter} that resulted in opening * it. If more than one implicitly opening {@code Receiver} or * {@code Transmitter} were obtained by the application, the device is closed * after the last {@code Receiver} or {@code Transmitter} has been closed. On * the other hand, calling {@code getReceiver} or {@code getTransmitter} on the * device instance directly does not open the device implicitly. Closing these * {@code Transmitter}s and {@code Receiver}s does not close the device * implicitly. To use a device with {@code Receiver}s or {@code Transmitter}s * obtained this way, the device has to be opened and closed explicitly. * <p> * If implicit and explicit opening and closing are mixed on the same * {@code MidiDevice} instance, the following rules apply: * * <ul> * <li>After an explicit open (either before or after implicit opens), the * device will not be closed by implicit closing. The only way to close an * explicitly opened device is an explicit close. * <li>An explicit close always closes the device, even if it also has been * opened implicitly. A subsequent implicit close has no further effect. * </ul> * * To detect if a MidiDevice represents a hardware MIDI port, the following * programming technique can be used: * * <pre>{@code * MidiDevice device = ...; * if (!(device instanceof Sequencer) && !(device instanceof Synthesizer)) { * // we're now sure that device represents a MIDI port * // ... * } * }</pre> * * <p> * A {@code MidiDevice} includes a {@link Info} object to provide manufacturer * information and so on. * * @author Kara Kytle * @author Florian Bomers * @see Synthesizer * @see Sequencer * @see Receiver * @see Transmitter */ public interface MidiDevice extends AutoCloseable { /** * Obtains information about the device, including its Java class and * {@code Strings} containing its name, vendor, and description. * * @return device info */ Info getDeviceInfo(); /** * Opens the device, indicating that it should now acquire any system * resources it requires and become operational. * <p> * An application opening a device explicitly with this call has to close * the device by calling {@link #close}. This is necessary to release system * resources and allow applications to exit cleanly. * <p> * Note that some devices, once closed, cannot be reopened. Attempts to * reopen such a device will always result in a * {@code MidiUnavailableException}. * * @throws MidiUnavailableException thrown if the device cannot be opened * due to resource restrictions * @throws SecurityException thrown if the device cannot be opened due to * security restrictions * @see #close * @see #isOpen */ void open() throws MidiUnavailableException; /** * Closes the device, indicating that the device should now release any * system resources it is using. * <p> * All {@code Receiver} and {@code Transmitter} instances open from this * device are closed. This includes instances retrieved via * {@code MidiSystem}. * * @see #open * @see #isOpen */ @Override void close(); /** * Reports whether the device is open. * * @return {@code true} if the device is open, otherwise {@code false} * @see #open * @see #close */ boolean isOpen(); /** * Obtains the current time-stamp of the device, in microseconds. If a * device supports time-stamps, it should start counting at 0 when the * device is opened and continue incrementing its time-stamp in microseconds * until the device is closed. If it does not support time-stamps, it should * always return -1. * * @return the current time-stamp of the device in microseconds, or -1 if * time-stamping is not supported by the device */ long getMicrosecondPosition(); /** * Obtains the maximum number of MIDI IN connections available on this MIDI * device for receiving MIDI data. * * @return maximum number of MIDI IN connections, or -1 if an unlimited * number of connections is available */ int getMaxReceivers(); /** * Obtains the maximum number of MIDI OUT connections available on this MIDI * device for transmitting MIDI data. * * @return maximum number of MIDI OUT connections, or -1 if an unlimited * number of connections is available */ int getMaxTransmitters(); /** * Obtains a MIDI IN receiver through which the MIDI device may receive MIDI * data. The returned receiver must be closed when the application has * finished using it. * <p> * Usually the returned receiver implements the {@code MidiDeviceReceiver} * interface. * <p> * Obtaining a {@code Receiver} with this method does not open the device. * To be able to use the device, it has to be opened explicitly by calling * {@link #open}. Also, closing the {@code Receiver} does not close the * device. It has to be closed explicitly by calling {@link #close}. * * @return a receiver for the device * @throws MidiUnavailableException thrown if a receiver is not available * due to resource restrictions * @see Receiver#close() */ Receiver getReceiver() throws MidiUnavailableException; /** * Returns all currently active, non-closed receivers connected with this * {@code MidiDevice}. A receiver can be removed from the device by closing * it. * <p> * Usually the returned receivers implement the {@code MidiDeviceReceiver} * interface. * * @return an unmodifiable list of the open receivers * @since 1.5 */ List<Receiver> getReceivers(); /** * Obtains a MIDI OUT connection from which the MIDI device will transmit * MIDI data. The returned transmitter must be closed when the application * has finished using it. * <p> * Usually the returned transmitter implements the * {@code MidiDeviceTransmitter} interface. * <p> * Obtaining a {@code Transmitter} with this method does not open the * device. To be able to use the device, it has to be opened explicitly by * calling {@link #open}. Also, closing the {@code Transmitter} does not * close the device. It has to be closed explicitly by calling * {@link #close}. * * @return a MIDI OUT transmitter for the device * @throws MidiUnavailableException thrown if a transmitter is not available * due to resource restrictions * @see Transmitter#close() */ Transmitter getTransmitter() throws MidiUnavailableException; /** * Returns all currently active, non-closed transmitters connected with this * {@code MidiDevice}. A transmitter can be removed from the device by * closing it. * <p> * Usually the returned transmitters implement the * {@code MidiDeviceTransmitter} interface. * * @return an unmodifiable list of the open transmitters * @since 1.5 */ List<Transmitter> getTransmitters(); /** * A {@code MidiDevice.Info} object contains assorted data about a * {@link MidiDevice}, including its name, the company who created it, and * descriptive text. * * @see MidiDevice#getDeviceInfo */ class Info { /** * The device's name. */ private final String name; /** * The name of the company who provides the device. */ private final String vendor; /** * A description of the device. */ private final String description; /** * Device version. */ private final String version; /** * Constructs a device info object. * * @param name the name of the device * @param vendor the name of the company who provides the device * @param description a description of the device * @param version version information for the device */ protected Info(String name, String vendor, String description, String version) { this.name = name; this.vendor = vendor; this.description = description; this.version = version; } /** * Indicates whether the specified object is equal to this info object, * returning {@code true} if the objects are the same. * * @param obj the reference object with which to compare * @return {@code true} if the specified object is equal to this info * object; {@code false} otherwise */ @Override public final boolean equals(Object obj) { return super.equals(obj); } /** * Returns a hash code value for this info object. * * @return a hash code value for this info object */ @Override public final int hashCode() { return super.hashCode(); } /** * Obtains the name of the device. * * @return a string containing the device's name */ public final String getName() { return name; } /** * Obtains the name of the company who supplies the device. * * @return device the vendor's name */ public final String getVendor() { return vendor; } /** * Obtains the description of the device. * * @return a description of the device */ public final String getDescription() { return description; } /** * Obtains the version of the device. * * @return textual version information for the device */ public final String getVersion() { return version; } /** * Provides a string representation of the device information. * * @return a description of the info object */ @Override public final String toString() { return name; } } }