javax.sound.midi
Class MidiSystem

java.lang.Object
  javax.sound.midi.MidiSystem

public class MidiSystem

extends Object

The MidiSystem class provides access to the installed MIDI system resources, including devices such as synthesizers, sequencers, and MIDI input and output ports. A typical simple MIDI application might begin by invoking one or more MidiSystem methods to learn what devices are installed and to obtain the ones needed in that application.

The class also has methods for reading files, streams, and URLs that contain standard MIDI file data or soundbanks. You can query the MidiSystem for the format of a specified MIDI file.

You cannot instantiate a MidiSystem; all the methods are static.

Method Summary

static MidiDevice	getMidiDevice(MidiDevice.Info info) Obtains the requested MIDI device.
static MidiDevice.Info[]	getMidiDeviceInfo() Obtains an array of information objects representing the set of all MIDI devices available on the system.
static MidiFileFormat	getMidiFileFormat(File file) Obtains the MIDI file format of the specified File.
static MidiFileFormat	getMidiFileFormat(InputStream stream) Obtains the MIDI file format of the data in the specified input stream.
static MidiFileFormat	getMidiFileFormat(URL url) Obtains the MIDI file format of the data in the specified URL.
static int[]	getMidiFileTypes() Obtains the set of MIDI file types for which file writing support is provided by the system.
static int[]	getMidiFileTypes(Sequence sequence) Obtains the set of MIDI file types that the system can write from the sequence specified.
static Receiver	getReceiver() Obtains a MIDI receiver from an external MIDI port or other default source.
static Sequence	getSequence(File file) Obtains a MIDI sequence from the specified File.
static Sequence	getSequence(InputStream stream) Obtains a MIDI sequence from the specified input stream.
static Sequence	getSequence(URL url) Obtains a MIDI sequence from the specified URL.
static Sequencer	getSequencer() Obtains the default sequencer.
static Soundbank	getSoundbank(File file) Constructs a Soundbank by reading it from the specified File.
static Soundbank	getSoundbank(InputStream stream) Constructs a MIDI sound bank by reading it from the specified stream.
static Soundbank	getSoundbank(URL url) Constructs a Soundbank by reading it from the specified URL.
static Synthesizer	getSynthesizer() Obtains the default synthesizer.
static Transmitter	getTransmitter() Obtains a MIDI transmitter from an external MIDI port or other default source.
static boolean	isFileTypeSupported(int fileType) Indicates whether file writing support for the specified MIDI file type is provided by the system.
static boolean	isFileTypeSupported(int fileType, Sequence sequence) Indicates whether a MIDI file of the file type specified can be written from the sequence indicated.
static int	write(Sequence in, int type, File out) Writes a stream of bytes representing a file of the MIDI file type indicated to the external file provided.
static int	write(Sequence in, int fileType, OutputStream out) Writes a stream of bytes representing a file of the MIDI file type indicated to the output stream provided.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

getMidiDeviceInfo

public static MidiDevice.Info[] getMidiDeviceInfo()

Obtains an array of information objects representing the set of all MIDI devices available on the system. A returned information object can then be used to obtain the corresponding device object, by invoking getMidiDevice.

Returns:

an array of MidiDevice.Info objects, one for each installed MIDI device. If no such devices are installed, an array of length 0 is returned.

getMidiDevice

public static MidiDevice getMidiDevice(MidiDevice.Info info)
                                throws MidiUnavailableException

Obtains the requested MIDI device.

Parameters:

info - a device information object representing the desired device.

Returns:

the requested device

Throws:

MidiUnavailableException - if the requested device is not available due to resource restrictions

IllegalArgumentException - if the info object does not represent a MIDI device installed on the system

See Also:

getMidiDeviceInfo()

getReceiver

public static Receiver getReceiver()
                            throws MidiUnavailableException

Obtains a MIDI receiver from an external MIDI port or other default source.

Returns:

the default MIDI receiver

Throws:

MidiUnavailableException - if the default receiver is not available due to resource restrictions

getTransmitter

public static Transmitter getTransmitter()
                                  throws MidiUnavailableException

Obtains a MIDI transmitter from an external MIDI port or other default source.

Returns:

the default MIDI transmitter

Throws:

MidiUnavailableException - if the default transmitter is not available due to resource restrictions

getSynthesizer

public static Synthesizer getSynthesizer()
                                  throws MidiUnavailableException

Obtains the default synthesizer.

Returns:

the default synthesizer

Throws:

MidiUnavailableException - if the synthesizer is not available due to resource restrictions

getSequencer

public static Sequencer getSequencer()
                              throws MidiUnavailableException

Obtains the default sequencer.

Returns:

the default sequencer

Throws:

MidiUnavailableException - if the sequencer is not available due to resource restrictions

getSoundbank

public static Soundbank getSoundbank(InputStream stream)
                              throws InvalidMidiDataException,
                                     IOException

Constructs a MIDI sound bank by reading it from the specified stream. The stream must point to a valid MIDI soundbank file. In general, MIDI soundbank providers may need to read some data from the stream before determining whether they support it. These parsers must be able to mark the stream, read enough data to determine whether they support the stream, and, if not, reset the stream's read pointer to its original position. If the input stream does not support this, this method may fail with an IOException.

Parameters:

stream - the source of the sound bank data.

Returns:

the sound bank

Throws:

InvalidMidiDataException - if the stream does not point to valid MIDI soundbank data recognized by the system

IOException - if an I/O error occurred when loading the soundbank

See Also:

InputStream.markSupported(), InputStream.mark(int)

getSoundbank

public static Soundbank getSoundbank(URL url)
                              throws InvalidMidiDataException,
                                     IOException

Constructs a Soundbank by reading it from the specified URL. The URL must point to a valid MIDI soundbank file.

Parameters:

url - the source of the sound bank data

Returns:

the sound bank

Throws:

InvalidMidiDataException - if the URL does not point to valid MIDI soundbank data recognized by the system

IOException - if an I/O error occurred when loading the soundbank

getSoundbank

public static Soundbank getSoundbank(File file)
                              throws InvalidMidiDataException,
                                     IOException

Constructs a Soundbank by reading it from the specified File. The File must point to a valid MIDI soundbank file.

Parameters:

file - the source of the sound bank data

Returns:

the sound bank

Throws:

InvalidMidiDataException - if the File does not point to valid MIDI soundbank data recognized by the system

IOException - if an I/O error occurred when loading the soundbank

getMidiFileFormat

public static MidiFileFormat getMidiFileFormat(InputStream stream)
                                        throws InvalidMidiDataException,
                                               IOException

Obtains the MIDI file format of the data in the specified input stream. The stream must point to valid MIDI file data for a file type recognized by the system.

This method and/or the code it invokes may need to read some data from the stream to determine whether its data format is supported. The implementation may therefore need to mark the stream, read enough data to determine whether it is in a supported format, and reset the stream's read pointer to its original position. If the input stream does not permit this set of operations, this method may fail with an IOException.

This operation can only succeed for files of a type which can be parsed by an installed file reader. It may fail with an InvalidMidiDataException even for valid files if no compatible file reader is installed. It will also fail with an InvalidMidiDataException if a compatible file reader is installed, but encounters errors while determining the file format.

Parameters:

stream - the input stream from which file format information should be extracted

Returns:

an MidiFileFormat object describing the MIDI file format

Throws:

InvalidMidiDataException - if the stream does not point to valid MIDI file data recognized by the system

IOException - if an I/O exception occurs while accessing the stream

See Also:

getMidiFileFormat(URL), getMidiFileFormat(File), InputStream.markSupported(), InputStream.mark(int)

getMidiFileFormat

public static MidiFileFormat getMidiFileFormat(URL url)
                                        throws InvalidMidiDataException,
                                               IOException

Obtains the MIDI file format of the data in the specified URL. The URL must point to valid MIDI file data for a file type recognized by the system.

This operation can only succeed for files of a type which can be parsed by an installed file reader. It may fail with an InvalidMidiDataException even for valid files if no compatible file reader is installed. It will also fail with an InvalidMidiDataException if a compatible file reader is installed, but encounters errors while determining the file format.

Parameters:

url - the URL from which file format information should be extracted

Returns:

a MidiFileFormat object describing the MIDI file format

Throws:

InvalidMidiDataException - if the URL does not point to valid MIDI file data recognized by the system

IOException - if an I/O exception occurs while accessing the URL

See Also:

getMidiFileFormat(InputStream), getMidiFileFormat(File)

getMidiFileFormat

public static MidiFileFormat getMidiFileFormat(File file)
                                        throws InvalidMidiDataException,
                                               IOException

Obtains the MIDI file format of the specified File. The File must point to valid MIDI file data for a file type recognized by the system.

This operation can only succeed for files of a type which can be parsed by an installed file reader. It may fail with an InvalidMidiDataException even for valid files if no compatible file reader is installed. It will also fail with an InvalidMidiDataException if a compatible file reader is installed, but encounters errors while determining the file format.

Parameters:

file - the File from which file format information should be extracted

Returns:

a MidiFileFormat object describing the MIDI file format

Throws:

InvalidMidiDataException - if the File does not point to valid MIDI file data recognized by the system

IOException - if an I/O exception occurs while accessing the file

See Also:

getMidiFileFormat(InputStream), getMidiFileFormat(URL)

getSequence

public static Sequence getSequence(InputStream stream)
                            throws InvalidMidiDataException,
                                   IOException

Obtains a MIDI sequence from the specified input stream. The stream must point to valid MIDI file data for a file type recognized by the system.

This method and/or the code it invokes may need to read some data from the stream to determine whether its data format is supported. The implementation may therefore need to mark the stream, read enough data to determine whether it is in a supported format, and reset the stream's read pointer to its original position. If the input stream does not permit this set of operations, this method may fail with an IOException.

This operation can only succeed for files of a type which can be parsed by an installed file reader. It may fail with an InvalidMidiDataException even for valid files if no compatible file reader is installed. It will also fail with an InvalidMidiDataException if a compatible file reader is installed, but encounters errors while constructing the Sequence object from the file data.

Parameters:

stream - the input stream from which the Sequence should be constructed

Returns:

a Sequence object based on the MIDI file data contained in the input stream

Throws:

InvalidMidiDataException - if the stream does not point to valid MIDI file data recognized by the system

IOException - if an I/O exception occurs while accessing the stream

See Also:

InputStream.markSupported(), InputStream.mark(int)

getSequence

public static Sequence getSequence(URL url)
                            throws InvalidMidiDataException,
                                   IOException

Obtains a MIDI sequence from the specified URL. The URL must point to valid MIDI file data for a file type recognized by the system.

This operation can only succeed for files of a type which can be parsed by an installed file reader. It may fail with an InvalidMidiDataException even for valid files if no compatible file reader is installed. It will also fail with an InvalidMidiDataException if a compatible file reader is installed, but encounters errors while constructing the Sequence object from the file data.

Parameters:

url - the URL from which the Sequence should be constructed

Returns:

a Sequence object based on the MIDI file data pointed to by the URL

Throws:

InvalidMidiDataException - if the URL does not point to valid MIDI file data recognized by the system

IOException - if an I/O exception occurs while accessing the URL

getSequence

public static Sequence getSequence(File file)
                            throws InvalidMidiDataException,
                                   IOException

Obtains a MIDI sequence from the specified File. The File must point to valid MIDI file data for a file type recognized by the system.

This operation can only succeed for files of a type which can be parsed by an installed file reader. It may fail with an InvalidMidiDataException even for valid files if no compatible file reader is installed. It will also fail with an InvalidMidiDataException if a compatible file reader is installed, but encounters errors while constructing the Sequence object from the file data.

Parameters:

file - the File from which the Sequence should be constructed

Returns:

a Sequence object based on the MIDI file data pointed to by the File

Throws:

InvalidMidiDataException - if the File does not point to valid MIDI file data recognized by the system

IOException - if an I/O exception occurs

getMidiFileTypes

public static int[] getMidiFileTypes()

Obtains the set of MIDI file types for which file writing support is provided by the system.

Returns:

array of file types. If no file types are supported, an array of length 0 is returned.

isFileTypeSupported

public static boolean isFileTypeSupported(int fileType)

Indicates whether file writing support for the specified MIDI file type is provided by the system.

Parameters:

fileType - the file type for which write capabilities are queried

Returns:

true if the file type is supported, otherwise false

getMidiFileTypes

public static int[] getMidiFileTypes(Sequence sequence)

Obtains the set of MIDI file types that the system can write from the sequence specified.

Parameters:

sequence - the sequence for which MIDI file type support is queried

Returns:

the set of supported file types. If no file types are supported, returns an array of length 0.

isFileTypeSupported

public static boolean isFileTypeSupported(int fileType,
                                          Sequence sequence)

Indicates whether a MIDI file of the file type specified can be written from the sequence indicated.

Parameters:

fileType - the file type for which write capabilities are queried

sequence - the sequence for which file writing support is queried

Returns:

true if the file type is supported for this sequence, otherwise false

write

public static int write(Sequence in,
                        int fileType,
                        OutputStream out)
                 throws IOException

Writes a stream of bytes representing a file of the MIDI file type indicated to the output stream provided.

Parameters:

in - sequence containing MIDI data to be written to the file

fileType - the file type of the file to be written to the output stream

out - stream to which the file data should be written

Returns:

the number of bytes written to the output stream

Throws:

IOException - if an I/O exception occurs

IllegalArgumentException - if the file format is not supported by the system

See Also:

isFileTypeSupported(int, Sequence), getMidiFileTypes(Sequence)

write

public static int write(Sequence in,
                        int type,
                        File out)
                 throws IOException

Writes a stream of bytes representing a file of the MIDI file type indicated to the external file provided.

Parameters:

in - sequence containing MIDI data to be written to the file

type - the file type of the file to be written to the output stream

out - external file to which the file data should be written

Returns:

the number of bytes written to the file

Throws:

IOException - if an I/O exception occurs

IllegalArgumentException - if the file type is not supported by the system

See Also:

isFileTypeSupported(int, Sequence), getMidiFileTypes(Sequence)