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.
Properties can be used to specify default MIDI devices. Both system properties and a properties file are considered. The "sound.properties" properties file is read from an implementation-specific location (typically it is the conf
directory in the Java installation directory). The optional "javax.sound.config.file" system property can be used to specify the properties file that will be read as the initial configuration. 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 the String
returned by the getName
method of MidiDevice.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 successfully 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 from getMidiDeviceInfo()
to contain all available MidiDevice.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 whose MidiDevice
implements the respective interface, will be returned. If no matching MidiDevice.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 property javax.sound.midi.Receiver
with a value "com.sun.media.sound.MidiProvider#SunMIDI1"
will have the following consequences when getReceiver
is called: if the class com.sun.media.sound.MidiProvider
exists in the list of installed MIDI device providers, the first Receiver
device with name "SunMIDI1"
will be returned. If it cannot be found, the first Receiver
from that provider will be returned, regardless of name. If there is none, the first Receiver
with name "SunMIDI1"
in the list of all devices (as returned by getMidiDeviceInfo
) will be returned, or, if not found, the first Receiver
that can be found in the list of all devices is returned. If that fails, too, a MidiUnavailableException
is thrown.
Method Summary
Modifier and Type | Method | 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 specified |
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 specified |
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 |
static Sequencer | getSequencer(boolean connected) | Obtains the default |
static Soundbank | getSoundbank(File file) | Constructs a |
static Soundbank | getSoundbank(InputStream stream) | Constructs a MIDI sound bank by reading it from the specified stream. |
static Soundbank | getSoundbank(URL url) | Constructs a |
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 declared in 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 -
NullPointerException
- ifinfo
isnull
- See Also:
getMidiDeviceInfo()
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 the MidiDeviceReceiver
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 the class 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 the MidiDeviceReceiver
interface. The corresponding Receiver
method calls will be forwarded to the native receiver.
If this method returns successfully, the MidiDevice
the Receiver
belongs to is opened implicitly, if it is not already open. It is possible to close an implicitly opened device by calling close
on the returned Receiver
. All open Receiver
instances have to be closed in order to release system resources hold by the MidiDevice
. For a detailed description of open/close behaviour see the class description of MidiDevice
.
- 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
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 the MidiDeviceTransmitter
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 the class 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 the MidiDeviceTransmitter
interface. The corresponding Transmitter
method calls will be forwarded to the native transmitter.
If this method returns successfully, the MidiDevice
the Transmitter
belongs to is opened implicitly, if it is not already open. It is possible to close an implicitly opened device by calling close
on the returned Transmitter
. All open Transmitter
instances have to be closed in order to release system resources hold by the MidiDevice
. For a detailed description of open/close behaviour see the class description of MidiDevice
.
- 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
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 the class 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
getSequencer
public static Sequencer getSequencer() throws MidiUnavailableException
Obtains the default Sequencer
, connected to a default device. The returned Sequencer
instance is connected to the default Synthesizer
, as returned by getSynthesizer()
. If there is no Synthesizer
available, or the default Synthesizer
cannot be opened, the sequencer
is connected to the default Receiver
, as returned by getReceiver()
. The connection is made by retrieving a Transmitter
instance from the Sequencer
and setting its Receiver
. 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 the class 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 default Sequencer
, optionally connected to a default device.
If connected
is true, the returned Sequencer
instance is connected to the default Synthesizer
, as returned by getSynthesizer()
. If there is no Synthesizer
available, or the default Synthesizer
cannot be opened, the sequencer
is connected to the default Receiver
, as returned by getReceiver()
. The connection is made by retrieving a Transmitter
instance from the Sequencer
and setting its Receiver
. Closing and re-opening the sequencer will restore the connection to the default device.
If connected
is false, the returned Sequencer
instance is not connected, it has no open Transmitters
. In order to play the sequencer on a MIDI device, or a Synthesizer
, it is necessary to get a Transmitter
and set its Receiver
.
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 the class description
.
- Parameters:
-
connected
- whether or not the returnedSequencer
is connected to the defaultSynthesizer
- 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()
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 -
NullPointerException
- ifstream
isnull
- 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 -
NullPointerException
- ifurl
isnull
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 theFile
does not point to valid MIDI soundbank data recognized by the system -
IOException
- if an I/O error occurred when loading the soundbank -
NullPointerException
- iffile
isnull
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 -
NullPointerException
- ifstream
isnull
- 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 -
NullPointerException
- ifurl
isnull
- 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
- 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 system -
IOException
- if an I/O exception occurs while accessing the file -
NullPointerException
- iffile
isnull
- 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 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 system -
IOException
- if an I/O exception occurs while accessing the stream -
NullPointerException
- ifstream
isnull
- 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 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 system -
IOException
- if an I/O exception occurs while accessing the URL -
NullPointerException
- ifurl
isnull
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
- 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 system -
IOException
- if an I/O exception occurs -
NullPointerException
- iffile
isnull
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.
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
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.
- Throws:
-
NullPointerException
- ifsequence
isnull
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, otherwisefalse
- Throws:
-
NullPointerException
- ifsequence
isnull
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 -
NullPointerException
- ifin
orout
arenull
- 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 -
NullPointerException
- ifin
orout
arenull
- See Also:
-
isFileTypeSupported(int, Sequence)
,getMidiFileTypes(Sequence)