Java javax.sound.sampled Interface TargetDataLine（JDK8）

Method Detail

• open

  void open(AudioFormat format,
            int bufferSize)
     throws LineUnavailableException

  Opens the line with the specified format and requested 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 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 that is already open is illegal and may result in an IllegalStateException.

  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, in bytes.

  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 if format is not fully specified or invalid

  IllegalStateException - if the line is already open

  SecurityException - if the line cannot be opened due to security restrictions

  See Also:

  open(AudioFormat), Line.open(), Line.close(), Line.isOpen(), LineEvent

• open

  void open(AudioFormat format)
     throws LineUnavailableException

  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 that is already open is illegal and may result in an IllegalStateException.

  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 - if format is not fully specified or invalid

  IllegalStateException - if the line is already open

  SecurityException - if the line cannot be opened due to security restrictions

  See Also:

  open(AudioFormat, int), Line.open(), Line.close(), Line.isOpen(), LineEvent

• read

  int read(byte[] b,
           int off,
           int len)

  Reads audio data from the data line's input buffer. The requested number of bytes is read into the specified array, starting at the specified offset into the array in bytes. This method blocks until the requested amount of data has been read. However, if the data line is closed, stopped, drained, or flushed before the requested amount has been read, the method no longer blocks, but returns the number of bytes read thus far.

  The number of bytes that can be read without blocking can be ascertained using the available method of the DataLine interface. (While it is guaranteed that this number of bytes can be read without blocking, there is no guarantee that attempts to read additional data will block.)

  The number of bytes to be read must represent an integral number of sample frames, such that:
  

  [ bytes read ] % [frame size in bytes ] == 0
  The return value will always meet this requirement. A request to read 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 that will contain the requested input data when this method returns

  off - the offset from the beginning of the array, in bytes

  len - the requested number of bytes to read

  Returns:

  the number of bytes actually read

  Throws:

  IllegalArgumentException - if the requested number of bytes does not represent an integral number of sample frames. or if len is negative.

  ArrayIndexOutOfBoundsException - if off is negative, or off+len is greater than the length of the array b.

  See Also:

  SourceDataLine.write(byte[], int, int), DataLine.available()