AutoCloseable
, Line
Clip
, SourceDataLine
, TargetDataLine
public interface DataLine extends Line
DataLine
adds media-related functionality to its superinterface, Line
. This functionality includes transport-control methods that start, stop, drain, and flush the audio data that passes through the line. A data line can also report the current position, volume, and audio format of the media. Data lines are used for output of audio by means of the subinterfaces SourceDataLine
or Clip
, which allow an application program to write data. Similarly, audio input is handled by the subinterface TargetDataLine
, which allows data to be read. A data line has an internal buffer in which the incoming or outgoing audio data is queued. The drain()
method blocks until this internal buffer becomes empty, usually because all queued data has been processed. The flush()
method discards any available queued data from the internal buffer.
A data line produces START
and STOP
events whenever it begins or ceases active presentation or capture of data. These events can be generated in response to specific requests, or as a result of less direct state changes. For example, if start()
is called on an inactive data line, and data is available for capture or playback, a START
event will be generated shortly, when data playback or capture actually begins. Or, if the flow of data to an active data line is constricted so that a gap occurs in the presentation of data, a STOP
event is generated.
Mixers often support synchronized control of multiple data lines. Synchronization can be established through the Mixer
interface's synchronize
method. See the description of the Mixer
interface for a more complete description.
Modifier and Type | Interface | Description |
---|---|---|
static class |
DataLine.Info |
Besides the class information inherited from its superclass, DataLine.Info provides additional information specific to data lines. |
Modifier and Type | Method | Description |
---|---|---|
int |
available() |
Obtains the number of bytes of data currently available to the application for processing in the data line's internal buffer. |
void |
drain() |
Drains queued data from the line by continuing data I/O until the data line's internal buffer has been emptied. |
void |
flush() |
Flushes queued data from the line. |
int |
getBufferSize() |
Obtains the maximum number of bytes of data that will fit in the data line's internal buffer. |
AudioFormat |
getFormat() |
Obtains the current format (encoding, sample rate, number of channels, etc.) of the data line's audio data. |
int |
getFramePosition() |
Obtains the current position in the audio data, in sample frames. |
float |
getLevel() |
Obtains the current volume level for the line. |
long |
getLongFramePosition() |
Obtains the current position in the audio data, in sample frames. |
long |
getMicrosecondPosition() |
Obtains the current position in the audio data, in microseconds. |
boolean |
isActive() |
Indicates whether the line is engaging in active I/O (such as playback or capture). |
boolean |
isRunning() |
Indicates whether the line is running. |
void |
start() |
Allows a line to engage in data I/O. |
void |
stop() |
Stops the line. |
addLineListener, close, getControl, getControls, getLineInfo, isControlSupported, isOpen, open, removeLineListener
void drain()
drain()
is invoked on a stopped line that has data in its queue, the method will block until the line is running and the data queue becomes empty. If drain()
is invoked by one thread, and another continues to fill the data queue, the operation will not complete. This method always returns when the data line is closed.void flush()
void start()
START
event is generated.void stop()
flush
method. When audio capture or playback stops, a STOP
event is generated.boolean isRunning()
false
. An open line begins running when the first data is presented in response to an invocation of the start
method, and continues until presentation ceases in response to a call to stop
or because playback completes.true
if the line is running, otherwise false
boolean isActive()
START
event to its listeners. Similarly, when an active line becomes inactive, it sends a STOP
event.true
if the line is actively capturing or rendering sound, otherwise false
AudioFormat getFormat()
If the line is not open and has never been opened, it returns the default format. The default format is an implementation specific audio format, or, if the DataLine.Info
object, which was used to retrieve this DataLine
, specifies at least one fully qualified audio format, the last one will be used as the default format. Opening the line with a specific audio format (e.g. SourceDataLine.open(AudioFormat)
) will override the default format.
int getBufferSize()
int available()
Note that the units used are bytes, but will always correspond to an integral number of sample frames of audio data.
An application is guaranteed that a read or write operation of up to the number of bytes returned from available()
will not block; however, there is no guarantee that attempts to read or write more data will block.
int getFramePosition()
getLongFramePosition
instead.long getLongFramePosition()
long getMicrosecondPosition()
float getLevel()
AudioSystem.NOT_SPECIFIED
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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
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https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/javax/sound/sampled/DataLine.html