- All Superinterfaces:
AutoCloseable
,DataLine
,Line
public interface SourceDataLine extends DataLine
Note that the naming convention for this interface reflects the relationship between the line and its mixer. From the perspective of an application, a source data line may act as a target for audio data.
A source data line can be obtained from a mixer by invoking the
getLine
method of Mixer
with an appropriate
DataLine.Info
object.
The SourceDataLine
interface provides a method for writing audio data
to the data line's buffer. Applications that play or mix audio should write
data to the source data line quickly enough to keep the buffer from
underflowing (emptying), which could cause discontinuities in the audio that
are perceived as clicks. Applications can use the
available
method defined in the DataLine
interface to determine the amount of data currently queued in the data line's
buffer. The amount of data which can be written to the buffer without
blocking is the difference between the buffer size and the amount of queued
data. If the delivery of audio output stops due to underflow, a
STOP
event is generated. A
START
event is generated when the audio output
resumes.
- Since:
- 1.3
- See Also:
Mixer
,DataLine
,TargetDataLine
-
Nested Class Summary
Nested classes/interfaces declared in interface javax.sound.sampled.DataLine
DataLine.Info
-
Method Summary
Modifier and Type Method Description void
open(AudioFormat format)
Opens the line with the specified format, causing the line to acquire any required system resources and become operational.void
open(AudioFormat format, int bufferSize)
Opens the line with the specified format and suggested buffer size, causing the line to acquire any required system resources and become operational.int
write(byte[] b, int off, int len)
Writes audio data to the mixer via this source data line.Methods declared in interface javax.sound.sampled.DataLine
available, drain, flush, getBufferSize, getFormat, getFramePosition, getLevel, getLongFramePosition, getMicrosecondPosition, isActive, isRunning, start, stop
Methods declared in interface javax.sound.sampled.Line
addLineListener, close, getControl, getControls, getLineInfo, isControlSupported, isOpen, open, removeLineListener
-
Method Details
-
open
Opens the line with the specified format and suggested buffer size, causing the line to acquire any required system resources and become operational.The buffer size is specified in bytes, but must represent an integral number of sample frames. Invoking this method with a requested buffer size that does not meet this requirement may result in an
IllegalArgumentException
. The actual buffer size for the open line may differ from the requested buffer size. The value actually set may be queried by subsequently callingDataLine.getBufferSize()
.If this operation succeeds, the line is marked as open, and an
OPEN
event is dispatched to the line's listeners.Invoking this method on a line which is already open is illegal and may result in an
IllegalStateException
.Note that some lines, once closed, cannot be reopened. Attempts to reopen such a line will always result in a
LineUnavailableException
.- Parameters:
format
- the desired audio formatbufferSize
- the desired buffer size- Throws:
LineUnavailableException
- if the line cannot be opened due to resource restrictionsIllegalArgumentException
- if the buffer size does not represent an integral number of sample frames, or ifformat
is not fully specified or invalidIllegalStateException
- if the line is already openSecurityException
- if the line cannot be opened due to security restrictions- See Also:
open(AudioFormat)
,Line.open()
,Line.close()
,Line.isOpen()
,LineEvent
-
open
Opens the line with the specified format, causing the line to acquire any required system resources and become operational.The implementation chooses a buffer size, which is measured in bytes but which encompasses an integral number of sample frames. The buffer size that the system has chosen may be queried by subsequently calling
DataLine.getBufferSize()
.If this operation succeeds, the line is marked as open, and an
OPEN
event is dispatched to the line's listeners.Invoking this method on a line which is already open is illegal and may result in an
IllegalStateException
.Note that some lines, once closed, cannot be reopened. Attempts to reopen such a line will always result in a
LineUnavailableException
.- Parameters:
format
- the desired audio format- Throws:
LineUnavailableException
- if the line cannot be opened due to resource restrictionsIllegalArgumentException
- ifformat
is not fully specified or invalidIllegalStateException
- if the line is already openSecurityException
- if the line cannot be opened due to security restrictions- See Also:
open(AudioFormat, int)
,Line.open()
,Line.close()
,Line.isOpen()
,LineEvent
-
write
int write(byte[] b, int off, int len)Writes audio data to the mixer via this source data line. The requested number of bytes of data are read from the specified array, starting at the given offset into the array, and written to the data line's buffer. If the caller attempts to write more data than can currently be written (seeavailable
), this method blocks until the requested amount of data has been written. This applies even if the requested amount of data to write is greater than the data line's buffer size. However, if the data line is closed, stopped, or flushed before the requested amount has been written, the method no longer blocks, but returns the number of bytes written thus far.The number of bytes that can be written without blocking can be ascertained using the
available
method of theDataLine
interface. (While it is guaranteed that this number of bytes can be written without blocking, there is no guarantee that attempts to write additional data will block.)The number of bytes to write must represent an integral number of sample frames, such that:
[ bytes written ] % [frame size in bytes ] == 0
The return value will always meet this requirement. A request to write a number of bytes representing a non-integral number of sample frames cannot be fulfilled and may result in an
IllegalArgumentException
.- Parameters:
b
- a byte array containing data to be written to the data lineoff
- the offset from the beginning of the array, in byteslen
- the length, in bytes, of the valid data in the array (in other words, the requested amount of data to write, in bytes)- Returns:
- the number of bytes actually written
- Throws:
IllegalArgumentException
- if the requested number of bytes does not represent an integral number of sample frames, or iflen
is negativeArrayIndexOutOfBoundsException
- ifoff
is negative, oroff+len
is greater than the length of the arrayb
- See Also:
TargetDataLine.read(byte[], int, int)
,DataLine.available()
-