Back to index...

	/*
	* Copyright (c) 1999, 2013, 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</code> is the base interface for all MIDI devices.
	* Common devices include synthesizers, sequencers, MIDI input ports, and MIDI
	* output ports.
	*
	* <p>A <code>MidiDevice</code> 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</code> 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</code> instance.
	* If an application opens a <code>MidiDevice</code>
	* 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 javax.sound.midi.MidiSystem#getReceiver
	* MidiSystem.getReceiver} and {@link
	* javax.sound.midi.MidiSystem#getTransmitter
	* MidiSystem.getTransmitter}. The <code>MidiDevice</code> used by
	* <code>MidiSystem.getReceiver</code> and
	* <code>MidiSystem.getTransmitter</code> is implementation-dependant
	* unless the properties <code>javax.sound.midi.Receiver</code>
	* and <code>javax.sound.midi.Transmitter</code> are used (see the
	* description of properties to select default providers in
	* {@link javax.sound.midi.MidiSystem}). A <code>MidiDevice</code>
	* that was opened implicitly, is closed implicitly by closing the
	* <code>Receiver</code> or <code>Transmitter</code> that resulted in
	* opening it. If more than one implicitly opening
	* <code>Receiver</code> or <code>Transmitter</code> were obtained by
	* the application, the device is closed after the last
	* <code>Receiver</code> or <code>Transmitter</code> has been
	* closed. On the other hand, calling <code>getReceiver</code> or
	* <code>getTransmitter</code> on the device instance directly does
	* not open the device implicitly. Closing these
	* <code>Transmitter</code>s and <code>Receiver</code>s does not close
	* the device implicitly. To use a device with <code>Receiver</code>s
	* or <code>Transmitter</code>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</code> 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>
	*
	* <li>An explicit close always closes the device, even if it also has
	* been opened implicitly. A subsequent implicit close has no further
	* effect.</li>
	* </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</code> includes a <code>{@link MidiDevice.Info}</code> object
	* to provide manufacturer information and so on.
	*
	* @see Synthesizer
	* @see Sequencer
	* @see Receiver
	* @see Transmitter
	*
	* @author Kara Kytle
	* @author Florian Bomers
	*/

	public interface MidiDevice extends AutoCloseable {


	/**
	* Obtains information about the device, including its Java class and
	* <code>Strings</code> containing its name, vendor, and description.
	*
	* @return device info
	*/
	public 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 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
	*/
	public void open() throws MidiUnavailableException;


	/**
	* Closes the device, indicating that the device should now release
	* any system resources it is using.
	*
	* <p>All <code>Receiver</code> and <code>Transmitter</code> instances
	* open from this device are closed. This includes instances retrieved
	* via <code>MidiSystem</code>.
	*
	* @see #open
	* @see #isOpen
	*/
	public void close();


	/**
	* Reports whether the device is open.
	*
	* @return <code>true</code> if the device is open, otherwise
	* <code>false</code>
	* @see #open
	* @see #close
	*/
	public 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.
	*/
	public 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.
	*/
	public 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.
	*/
	public 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</code> 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</code> 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()
	*/
	public Receiver getReceiver() throws MidiUnavailableException;


	/**
	* Returns all currently active, non-closed receivers
	* connected with this 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</code> 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</code> 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()
	*/
	public Transmitter getTransmitter() throws MidiUnavailableException;


	/**
	* Returns all currently active, non-closed transmitters
	* connected with this 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</code> object contains assorted
	* data about a <code>{@link MidiDevice}</code>, including its
	* name, the company who created it, and descriptive text.
	*
	* @see MidiDevice#getDeviceInfo
	*/
	public static class Info {

	/**
	* The device's name.
	*/
	private String name;

	/**
	* The name of the company who provides the device.
	*/
	private String vendor;

	/**
	* A description of the device.
	*/
	private String description;

	/**
	* Device version.
	*/
	private 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;
	}


	/**
	* Reports whether two objects are equal.
	* Returns <code>true</code> if the objects are identical.
	* @param obj the reference object with which to compare this
	* object
	* @return <code>true</code> if this object is the same as the
	* <code>obj</code> argument; <code>false</code> otherwise
	*/
	public final boolean equals(Object obj) {
	return super.equals(obj);
	}


	/**
	* Finalizes the hashcode method.
	*/
	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
	*/
	public final String toString() {
	return name;
	}
	} // class Info


	}

Back to index...