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MidiFileFormat (Java 2 Platform SE 5.0) - JDK 5 Documentation v1.5.0, Java 2 SDK 英文文档

JavaTM 2 Platform
Standard Ed. 5.0

javax.sound.midi
Class MidiFileFormat

java.lang.Object
  extended by javax.sound.midi.MidiFileFormat

public class MidiFileFormat
extends Object

A MidiFileFormat object encapsulates a MIDI file's type, as well as its length and timing information.

A MidiFileFormat object can include a set of properties. A property is a pair of key and value: the key is of type String, the associated property value is an arbitrary object. Properties specify additional informational meta data (like a author, or copyright). Properties are optional information, and file reader and file writer implementations are not required to provide or recognize properties.

The following table lists some common properties that should be used in implementations:
Property key Value type Description
"author" String name of the author of this file
"title" String title of this file
"copyright" String copyright message
"date" Date date of the recording or release
"comment" String an arbitrary text

See Also:
MidiSystem.getMidiFileFormat(java.io.File), Sequencer.setSequence(java.io.InputStream stream)

Field Summary
protected  int byteLength
          The length of the MIDI file in bytes.
protected  float divisionType
          The division type of the MIDI file.
protected  long microsecondLength
          The duration of the MIDI file in microseconds.
protected  int resolution
          The timing resolution of the MIDI file.
protected  int type
          The type of MIDI file.
static int UNKNOWN_LENGTH
          Represents unknown length.
 
Constructor Summary
MidiFileFormat(int type, float divisionType, int resolution, int bytes, long microseconds)
          Constructs a MidiFileFormat.
MidiFileFormat(int type, float divisionType, int resolution, int bytes, long microseconds, Map<String,Object> properties)
          Construct a MidiFileFormat with a set of properties.
 
Method Summary
 int getByteLength()
          Obtains the length of the MIDI file, expressed in 8-bit bytes.
 float getDivisionType()
          Obtains the timing division type for the MIDI file.
 long getMicrosecondLength()
          Obtains the length of the MIDI file, expressed in microseconds.
 Object getProperty(String key)
          Obtain the property value specified by the key.
 int getResolution()
          Obtains the timing resolution for the MIDI file.
 int getType()
          Obtains the MIDI file type.
 Map<String,Object> properties()
          Obtain an unmodifiable map of properties.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

UNKNOWN_LENGTH

public static final int UNKNOWN_LENGTH
Represents unknown length.

See Also:
getByteLength(), getMicrosecondLength(), Constant Field Values

type

protected int type
The type of MIDI file.


divisionType

protected float divisionType
The division type of the MIDI file.

See Also:
Sequence.PPQ, Sequence.SMPTE_24, Sequence.SMPTE_25, Sequence.SMPTE_30DROP, Sequence.SMPTE_30

resolution

protected int resolution
The timing resolution of the MIDI file.


byteLength

protected int byteLength
The length of the MIDI file in bytes.


microsecondLength

protected long microsecondLength
The duration of the MIDI file in microseconds.

Constructor Detail

MidiFileFormat

public MidiFileFormat(int type,
                      float divisionType,
                      int resolution,
                      int bytes,
                      long microseconds)
Constructs a MidiFileFormat.

Parameters:
type - the MIDI file type (0, 1, or 2)
divisionType - the timing division type (PPQ or one of the SMPTE types)
resolution - the timing resolution
bytes - the length of the MIDI file in bytes, or UNKNOWN_LENGTH if not known
microseconds - the duration of the file in microseconds, or UNKNOWN_LENGTH if not known
See Also:
UNKNOWN_LENGTH, Sequence.PPQ, Sequence.SMPTE_24, Sequence.SMPTE_25, Sequence.SMPTE_30DROP, Sequence.SMPTE_30

MidiFileFormat

public MidiFileFormat(int type,
                      float divisionType,
                      int resolution,
                      int bytes,
                      long microseconds,
                      Map<String,Object> properties)
Construct a MidiFileFormat with a set of properties.

Parameters:
type - the MIDI file type (0, 1, or 2)
divisionType - the timing division type (PPQ or one of the SMPTE types)
resolution - the timing resolution
bytes - the length of the MIDI file in bytes, or UNKNOWN_LENGTH if not known
microseconds - the duration of the file in microseconds, or UNKNOWN_LENGTH if not known
properties - a Map<String,Object> object with properties
Since:
1.5
See Also:
UNKNOWN_LENGTH, Sequence.PPQ, Sequence.SMPTE_24, Sequence.SMPTE_25, Sequence.SMPTE_30DROP, Sequence.SMPTE_30
Method Detail

getType

public int getType()
Obtains the MIDI file type.

Returns:
the file's type (0, 1, or 2)

getDivisionType

public float getDivisionType()
Obtains the timing division type for the MIDI file.

Returns:
the division type (PPQ or one of the SMPTE types)
See Also:
Sequence.Sequence(float, int), Sequence.PPQ, Sequence.SMPTE_24, Sequence.SMPTE_25, Sequence.SMPTE_30DROP, Sequence.SMPTE_30, Sequence.getDivisionType()

getResolution

public int getResolution()
Obtains the timing resolution for the MIDI file. If the division type is PPQ, the resolution is specified in ticks per beat. For SMTPE timing, the resolution is specified in ticks per frame.

Returns:
the number of ticks per beat (PPQ) or per frame (SMPTE)
See Also:
getDivisionType(), Sequence.getResolution()

getByteLength

public int getByteLength()
Obtains the length of the MIDI file, expressed in 8-bit bytes.

Returns:
the number of bytes in the file, or UNKNOWN_LENGTH if not known
See Also:
UNKNOWN_LENGTH

getMicrosecondLength

public long getMicrosecondLength()
Obtains the length of the MIDI file, expressed in microseconds.

Returns:
the file's duration in microseconds, or UNKNOWN_LENGTH if not known
See Also:
Sequence.getMicrosecondLength(), getByteLength(), UNKNOWN_LENGTH

properties

public Map<String,Object> properties()
Obtain an unmodifiable map of properties. The concept of properties is further explained in the class description.

Returns:
a Map<String,Object> object containing all properties. If no properties are recognized, an empty map is returned.
Since:
1.5
See Also:
getProperty(String)

getProperty

public Object getProperty(String key)
Obtain the property value specified by the key. The concept of properties is further explained in the class description.

If the specified property is not defined for a particular file format, this method returns null.

Parameters:
key - the key of the desired property
Returns:
the value of the property with the specified key, or null if the property does not exist.
Since:
1.5
See Also:
properties

JavaTM 2 Platform
Standard Ed. 5.0

Submit a bug or feature
For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2004 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.