- java.lang.Object
-
- javax.sound.midi.MidiSystem
-
public class MidiSystem extends Object
TheMidiSystem
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 moreMidiSystem
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.Properties can be used to specify default MIDI devices. Both system properties and a properties file are considered. The properties file is "lib/sound.properties" in the JRE directory. If a property exists both as a system property and in the properties file, the system property takes precedence. If none is specified, a suitable default is chosen among the available devices. The syntax of the properties file is specified in
Properties.load
. The following table lists the available property keys and which methods consider them:Property Key Interface Affected Method javax.sound.midi.Receiver
Receiver
getReceiver()
javax.sound.midi.Sequencer
Sequencer
getSequencer()
javax.sound.midi.Synthesizer
Synthesizer
getSynthesizer()
javax.sound.midi.Transmitter
Transmitter
getTransmitter()
MIDI device provider
class. The device name is matched against theString
returned by thegetName
method ofMidiDevice.Info
. Either the class name, or the device name may be omitted. If only the class name is specified, the trailing hash mark is optional.If the provider class is specified, and it can be successully retrieved from the installed providers, the list of
MidiDevice.Info
objects is retrieved from the provider. Otherwise, or when these devices do not provide a subsequent match, the list is retrieved fromgetMidiDeviceInfo()
to contain all availableMidiDevice.Info
objects.If a device name is specified, the resulting list of
MidiDevice.Info
objects is searched: the first one with a matching name, and whoseMidiDevice
implements the respective interface, will be returned. If no matchingMidiDevice.Info
object is found, or the device name is not specified, the first suitable device from the resulting list will be returned. For Sequencer and Synthesizer, a device is suitable if it implements the respective interface; whereas for Receiver and Transmitter, a device is suitable if it implements neither Sequencer nor Synthesizer and provides at least one Receiver or Transmitter, respectively. For example, the propertyjavax.sound.midi.Receiver
with a value"com.sun.media.sound.MidiProvider#SunMIDI1"
will have the following consequences whengetReceiver
is called: if the classcom.sun.media.sound.MidiProvider
exists in the list of installed MIDI device providers, the firstReceiver
device with name"SunMIDI1"
will be returned. If it cannot be found, the firstReceiver
from that provider will be returned, regardless of name. If there is none, the firstReceiver
with name"SunMIDI1"
in the list of all devices (as returned bygetMidiDeviceInfo
) will be returned, or, if not found, the firstReceiver
that can be found in the list of all devices is returned. If that fails, too, aMidiUnavailableException
is thrown.
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Method Summary
Methods Modifier and Type Method and Description 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 specifiedFile
.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 device.static Sequence
getSequence(File file)
Obtains a MIDI sequence from the specifiedFile
.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 defaultSequencer
, connected to a default device.static Sequencer
getSequencer(boolean connected)
Obtains the defaultSequencer
, optionally connected to a default device.static Soundbank
getSoundbank(File file)
Constructs aSoundbank
by reading it from the specifiedFile
.static Soundbank
getSoundbank(InputStream stream)
Constructs a MIDI sound bank by reading it from the specified stream.static Soundbank
getSoundbank(URL url)
Constructs aSoundbank
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.
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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 invokinggetMidiDevice
.- 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.
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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 restrictionsIllegalArgumentException
- if the info object does not represent a MIDI device installed on the system- See Also:
getMidiDeviceInfo()
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getReceiver
public static Receiver getReceiver() throws MidiUnavailableException
Obtains a MIDI receiver from an external MIDI port or other default device. The returned receiver always implements theMidiDeviceReceiver
interface.If the system property
javax.sound.midi.Receiver
is defined or it is defined in the file "sound.properties", it is used to identify the device that provides the default receiver. For details, refer to theclass description
. If a suitable MIDI port is not available, the Receiver is retrieved from an installed synthesizer.If a native receiver provided by the default device does not implement the
MidiDeviceReceiver
interface, it will be wrapped in a wrapper class that implements theMidiDeviceReceiver
interface. The correspondingReceiver
method calls will be forwarded to the native receiver.If this method returns successfully, the
MidiDevice
theReceiver
belongs to is opened implicitly, if it is not already open. It is possible to close an implicitly opened device by callingclose
on the returnedReceiver
. All openReceiver
instances have to be closed in order to release system resources hold by theMidiDevice
. For a detailed description of open/close behaviour see the class description ofMidiDevice
.- Returns:
- the default MIDI receiver
- Throws:
MidiUnavailableException
- if the default receiver is not available due to resource restrictions, or no device providing receivers is installed in the system
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getTransmitter
public static Transmitter getTransmitter() throws MidiUnavailableException
Obtains a MIDI transmitter from an external MIDI port or other default source. The returned transmitter always implements theMidiDeviceTransmitter
interface.If the system property
javax.sound.midi.Transmitter
is defined or it is defined in the file "sound.properties", it is used to identify the device that provides the default transmitter. For details, refer to theclass description
.If a native transmitter provided by the default device does not implement the
MidiDeviceTransmitter
interface, it will be wrapped in a wrapper class that implements theMidiDeviceTransmitter
interface. The correspondingTransmitter
method calls will be forwarded to the native transmitter.If this method returns successfully, the
MidiDevice
theTransmitter
belongs to is opened implicitly, if it is not already open. It is possible to close an implicitly opened device by callingclose
on the returnedTransmitter
. All openTransmitter
instances have to be closed in order to release system resources hold by theMidiDevice
. For a detailed description of open/close behaviour see the class description ofMidiDevice
.- Returns:
- the default MIDI transmitter
- Throws:
MidiUnavailableException
- if the default transmitter is not available due to resource restrictions, or no device providing transmitters is installed in the system
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getSynthesizer
public static Synthesizer getSynthesizer() throws MidiUnavailableException
Obtains the default synthesizer.If the system property
javax.sound.midi.Synthesizer
is defined or it is defined in the file "sound.properties", it is used to identify the default synthesizer. For details, refer to theclass description
.- Returns:
- the default synthesizer
- Throws:
MidiUnavailableException
- if the synthesizer is not available due to resource restrictions, or no synthesizer is installed in the system
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getSequencer
public static Sequencer getSequencer() throws MidiUnavailableException
Obtains the defaultSequencer
, connected to a default device. The returnedSequencer
instance is connected to the defaultSynthesizer
, as returned bygetSynthesizer()
. If there is noSynthesizer
available, or the defaultSynthesizer
cannot be opened, thesequencer
is connected to the defaultReceiver
, as returned bygetReceiver()
. The connection is made by retrieving aTransmitter
instance from theSequencer
and setting itsReceiver
. Closing and re-opening the sequencer will restore the connection to the default device.This method is equivalent to calling
getSequencer(true)
.If the system property
javax.sound.midi.Sequencer
is defined or it is defined in the file "sound.properties", it is used to identify the default sequencer. For details, refer to theclass description
.- Returns:
- the default sequencer, connected to a default Receiver
- Throws:
MidiUnavailableException
- if the sequencer is not available due to resource restrictions, or there is noReceiver
available by any installedMidiDevice
, or no sequencer is installed in the system.- See Also:
getSequencer(boolean)
,getSynthesizer()
,getReceiver()
-
getSequencer
public static Sequencer getSequencer(boolean connected) throws MidiUnavailableException
Obtains the defaultSequencer
, optionally connected to a default device.If
connected
is true, the returnedSequencer
instance is connected to the defaultSynthesizer
, as returned bygetSynthesizer()
. If there is noSynthesizer
available, or the defaultSynthesizer
cannot be opened, thesequencer
is connected to the defaultReceiver
, as returned bygetReceiver()
. The connection is made by retrieving aTransmitter
instance from theSequencer
and setting itsReceiver
. Closing and re-opening the sequencer will restore the connection to the default device.If
connected
is false, the returnedSequencer
instance is not connected, it has no openTransmitters
. In order to play the sequencer on a MIDI device, or aSynthesizer
, it is necessary to get aTransmitter
and set itsReceiver
.If the system property
javax.sound.midi.Sequencer
is defined or it is defined in the file "sound.properties", it is used to identify the default sequencer. For details, refer to theclass description
.- Returns:
- the default sequencer
- Throws:
MidiUnavailableException
- if the sequencer is not available due to resource restrictions, or no sequencer is installed in the system, or ifconnected
is true, and there is noReceiver
available by any installedMidiDevice
- Since:
- 1.5
- See Also:
getSynthesizer()
,getReceiver()
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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 systemIOException
- if an I/O error occurred when loading the soundbank- See Also:
InputStream.markSupported()
,InputStream.mark(int)
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getSoundbank
public static Soundbank getSoundbank(URL url) throws InvalidMidiDataException, IOException
Constructs aSoundbank
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 systemIOException
- if an I/O error occurred when loading the soundbank
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getSoundbank
public static Soundbank getSoundbank(File file) throws InvalidMidiDataException, IOException
Constructs aSoundbank
by reading it from the specifiedFile
. TheFile
must point to a valid MIDI soundbank file.- Parameters:
file
- the source of the sound bank data- Returns:
- the sound bank
- Throws:
InvalidMidiDataException
- if theFile
does not point to valid MIDI soundbank data recognized by the systemIOException
- if an I/O error occurred when loading the soundbank
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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 systemIOException
- if an I/O exception occurs while accessing the stream- See Also:
getMidiFileFormat(URL)
,getMidiFileFormat(File)
,InputStream.markSupported()
,InputStream.mark(int)
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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 systemIOException
- if an I/O exception occurs while accessing the URL- See Also:
getMidiFileFormat(InputStream)
,getMidiFileFormat(File)
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getMidiFileFormat
public static MidiFileFormat getMidiFileFormat(File file) throws InvalidMidiDataException, IOException
Obtains the MIDI file format of the specifiedFile
. TheFile
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
- theFile
from which file format information should be extracted- Returns:
- a
MidiFileFormat
object describing the MIDI file format - Throws:
InvalidMidiDataException
- if theFile
does not point to valid MIDI file data recognized by the systemIOException
- if an I/O exception occurs while accessing the file- See Also:
getMidiFileFormat(InputStream)
,getMidiFileFormat(URL)
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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 theSequence
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 systemIOException
- if an I/O exception occurs while accessing the stream- See Also:
InputStream.markSupported()
,InputStream.mark(int)
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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 theSequence
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 systemIOException
- if an I/O exception occurs while accessing the URL
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getSequence
public static Sequence getSequence(File file) throws InvalidMidiDataException, IOException
Obtains a MIDI sequence from the specifiedFile
. TheFile
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
- theFile
from which theSequence
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 systemIOException
- if an I/O exception occurs
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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 unique file types. If no file types are supported, an array of length 0 is returned.
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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, otherwisefalse
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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 unique supported file types. If no file types are supported, returns an array of length 0.
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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 queriedsequence
- the sequence for which file writing support is queried- Returns:
true
if the file type is supported for this sequence, otherwisefalse
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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 filefileType
- the file type of the file to be written to the output streamout
- 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 occursIllegalArgumentException
- if the file format is not supported by the system- See Also:
isFileTypeSupported(int, Sequence)
,getMidiFileTypes(Sequence)
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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 filetype
- the file type of the file to be written to the output streamout
- 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 occursIllegalArgumentException
- if the file type is not supported by the system- See Also:
isFileTypeSupported(int, Sequence)
,getMidiFileTypes(Sequence)
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Document created the 11/06/2005, last modified the 04/03/2020
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