Interface SourceDataLine
- 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:
Nested Class Summary
Nested classes/interfaces declared in interface DataLine
DataLine.Info | 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. |
Method Summary
| Modifier and Type | Method | Description |
|---|---|---|
void |
open |
Opens the line with the specified format, causing the line to acquire any required system resources and become operational. |
void |
open |
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 |
Writes audio data to the mixer via this source data line. |
Methods declared in interface DataLine
available, drain, flush, getBufferSize, getFormat, getFramePosition, getLevel, getLongFramePosition, getMicrosecondPosition, isActive, isRunning, start, stop | 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. |
Methods declared in interface Line
addLineListener, close, getControl, getControls, getLineInfo, isControlSupported, isOpen, open, removeLineListener | Modifier and Type | Method | Description |
|---|---|---|
void |
addLineListener |
Adds a listener to this line. |
void |
close() |
Closes the line, indicating that any system resources in use by the line can be released. |
Control |
getControl |
Obtains a control of the specified type, if there is any. |
Control[] |
getControls() |
Obtains the set of controls associated with this line. |
Line.Info |
getLineInfo() |
Obtains the Line.Info object describing this line. |
boolean |
isControlSupported |
Indicates whether the line supports a control of the specified type. |
boolean |
isOpen() |
Indicates whether the line is open, meaning that it has reserved system resources and is operational, although it might not currently be playing or capturing sound. |
void |
open() |
Opens the line, indicating that it should acquire any required system resources and become operational. |
void |
removeLineListener |
Removes the specified listener from this line's list of listeners. |
Method Details
open
void open(AudioFormat format, int bufferSize) throws LineUnavailableException
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 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 -
bufferSize- the desired buffer size - Throws:
-
LineUnavailableException- if the line cannot be opened due to resource restrictions -
IllegalArgumentException- if the buffer size does not represent an integral number of sample frames, or ifformatis not fully specified or invalid -
IllegalStateException- if the line is already open - See Also:
open
void open(AudioFormat format) throws LineUnavailableException
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 restrictions -
IllegalArgumentException- ifformatis not fully specified or invalid -
IllegalStateException- if the line is already open - See Also:
write
int write(byte[] b, int off, int len)
available), 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 the DataLine 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 line -
off- the offset from the beginning of the array, in bytes -
len- 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 iflenis negative -
ArrayIndexOutOfBoundsException- ifoffis negative, oroff+lenis greater than the length of the arrayb - See Also:
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