Linepublic interface Line The Line interface represents a mono or multi-channel
audio feed. A line is an element of the digital audio
"pipeline," such as a mixer, an input or output port,
or a data path into or out of a mixer.
A line can have controls, such as gain, pan, and reverb.
The controls themselves are instances of classes that extend the
base {@link Control} class.
The Line interface provides two accessor methods for
obtaining the line's controls: {@link #getControls getControls} returns the
entire set, and {@link #getControl getControl} returns a single control of
specified type.
Lines exist in various states at different times. When a line opens, it reserves system
resources for itself, and when it closes, these resources are freed for
other objects or applications. The {@link #isOpen()} method lets
you discover whether a line is open or closed.
An open line need not be processing data, however. Such processing is
typically initiated by subinterface methods such as
{@link SourceDataLine#write SourceDataLine.write} and
{@link TargetDataLine#read TargetDataLine.read}.
You can register an object to receive notifications whenever the line's
state changes. The object must implement the {@link LineListener}
interface, which consists of the single method
{@link LineListener#update update}.
This method will be invoked when a line opens and closes (and, if it's a
{@link DataLine}, when it starts and stops).
An object can be registered to listen to multiple lines. The event it
receives in its update method will specify which line created
the event, what type of event it was
(OPEN, CLOSE, START, or STOP),
and how many sample frames the line had processed at the time the event occurred.
Certain line operations, such as open and close, can generate security
exceptions if invoked by unprivileged code when the line is a shared audio
resource. |
| Methods Summary |
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| public void | addLineListener(javax.sound.sampled.LineListener listener)Adds a listener to this line. Whenever the line's status changes, the
listener's update() method is called with a LineEvent object
that describes the change.
| | public void | close()Closes the line, indicating that any system resources
in use by the line can be released. If this operation
succeeds, the line is marked closed and a CLOSE event is dispatched
to the line's listeners.
| | public javax.sound.sampled.Control | getControl(javax.sound.sampled.Control$Type control)Obtains a control of the specified type,
if there is any.
Some controls may only be available when the line is open.
| | public javax.sound.sampled.Control[] | getControls()Obtains the set of controls associated with this line.
Some controls may only be available when the line is open.
If there are no controls, this method returns an array of length 0.
| | public javax.sound.sampled.Line$Info | getLineInfo()Obtains the Line.Info object describing this
line.
| | public boolean | isControlSupported(javax.sound.sampled.Control$Type control)Indicates whether the line supports a control of the specified type.
Some controls may only be available when the line is open.
| | public 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.
| | public void | open()Opens the line, indicating that it should acquire any required
system resources and become operational.
If this operation
succeeds, the line is marked as open, and an OPEN event is dispatched
to the line's listeners.
Note that some lines, once closed, cannot be reopened. Attempts
to reopen such a line will always result in an LineUnavailableException.
Some types of lines have configurable properties that may affect
resource allocation. For example, a DataLine must
be opened with a particular format and buffer size. Such lines
should provide a mechanism for configuring these properties, such
as an additional open method or methods which allow
an application to specify the desired settings.
This method takes no arguments, and opens the line with the current
settings. For {@link SourceDataLine} and
{@link TargetDataLine} objects, this means that the line is
opened with default settings. For a {@link Clip}, however,
the buffer size is determined when data is loaded. Since this method does not
allow the application to specify any data to load, an IllegalArgumentException
is thrown. Therefore, you should instead use one of the open methods
provided in the Clip interface to load data into the Clip.
For DataLine's, if the DataLine.Info
object which was used to retrieve the line, specifies at least
one fully qualified audio format, the last one will be used
as the default format.
| | public void | removeLineListener(javax.sound.sampled.LineListener listener)Removes the specified listener from this line's list of listeners.
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