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   * Copyright (c) 1999, 2003, Oracle and/or its affiliates. All rights reserved.
   * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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  package lib.sound.sampled;
  
  
  /**
   * A source data line is a data line to which data may be written.  It acts as
   * a source to its mixer. An application writes audio bytes to a source data line,
   * which handles the buffering of the bytes and delivers them to the mixer.
   * The mixer may mix the samples with those from other sources and then deliver
   * the mix to a target such as an output port (which may represent an audio output
   * device on a sound card).
   * <p/>
   * 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.
   * <p/>
   * A source data line can be obtained from a mixer by invoking the
   * <code>{@link Mixer#getLine getLine}</code> method of <code>Mixer</code> with
   * an appropriate <code>{@link DataLine.Info}</code> object.
   * <p/>
   * The <code>SourceDataLine</code> 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
   * <code>{@link DataLine#available available}</code> method defined in the
   * <code>DataLine</code> 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 <code>{@link LineEvent.Type#STOP STOP}</code> event is
   * generated.  A <code>{@link LineEvent.Type#START START}</code> event is generated
   * when the audio output resumes.
   *
   * @author Kara Kytle
   * @see Mixer
   * @see DataLine
   * @see TargetDataLine
   * @since 1.3
   */
  public interface SourceDataLine extends DataLine {
  
  
      /**
       * Opens the line with the specified format and suggested buffer size,
       * causing the line to acquire any required
       * system resources and become operational.
       * <p/>
       * 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 <code>{@link DataLine#getBufferSize}</code>.
       * <p/>
       * If this operation succeeds, the line is marked as open, and an
       * <code>{@link LineEvent.Type#OPEN OPEN}</code> event is dispatched to the
       * line's listeners.
       * <p/>
       * Invoking this method on a line which is already open is illegal
       * and may result in an <code>IllegalStateException</code>.
       * <p/>
       * Note that some lines, once closed, cannot be reopened.  Attempts
       * to reopen such a line will always result in a
       * <code>LineUnavailableException</code>.
       *
       * @param format     the desired audio format
       * @param bufferSize the desired buffer size
       * @throws LineUnavailableException if the line cannot be
       *                                  opened due to resource restrictions
       * @throws IllegalArgumentException if the buffer size does not represent
       *                                  an integral number of sample frames,
       *                                  or if <code>format</code> is not fully specified or invalid
       * @throws IllegalStateException    if the line is already open
       * @throws SecurityException        if the line cannot be
       *                                  opened due to security restrictions
       * @see #open(AudioFormat)
       * @see Line#open
       * @see Line#close
       * @see Line#isOpen
       * @see LineEvent
       */
      void open(AudioFormat format, int bufferSize) throws LineUnavailableException;
  
  
      /**
       * Opens the line with the specified format, causing the line to acquire any
       * required system resources and become operational.
       * <p/>
       * <p/>
       * 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
       * <code>{@link DataLine#getBufferSize}</code>.
       * <p/>
       * If this operation succeeds, the line is marked as open, and an
       * <code>{@link LineEvent.Type#OPEN OPEN}</code> event is dispatched to the
       * line's listeners.
       * <p/>
       * Invoking this method on a line which is already open is illegal
       * and may result in an <code>IllegalStateException</code>.
       * <p/>
       * Note that some lines, once closed, cannot be reopened.  Attempts
       * to reopen such a line will always result in a
       * <code>LineUnavailableException</code>.
       *
       * @param format the desired audio format
       * @throws LineUnavailableException if the line cannot be
       *                                  opened due to resource restrictions
       * @throws IllegalArgumentException if <code>format</code>
       *                                  is not fully specified or invalid
       * @throws IllegalStateException    if the line is already open
       * @throws SecurityException        if the line cannot be
       *                                  opened due to security restrictions
       * @see #open(AudioFormat, int)
       * @see Line#open
       * @see Line#close
       * @see Line#isOpen
       * @see LineEvent
       */
      void open(AudioFormat format) throws LineUnavailableException;
  
  
      /**
       * 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 (see <code>{@link DataLine#available available}</code>),
       * 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.
       * <p/>
       * The number of bytes that can be written without blocking can be ascertained
       * using the <code>{@link DataLine#available available}</code> method of the
       * <code>DataLine</code> 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.)
       * <p/>
       * The number of bytes to write must represent an integral number of
       * sample frames, such that:
       * <br>
       * <center><code>[ bytes written ] % [frame size in bytes ] == 0</code></center>
       * <br>
       * 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 <code>IllegalArgumentException</code>.
       *
       * @param b   a byte array containing data to be written to the data line
       * @param len the length, in bytes, of the valid data in the array
       *            (in other words, the requested amount of data to write, in bytes)
       * @param off the offset from the beginning of the array, in bytes
       * @return the number of bytes actually written
       * @throws IllegalArgumentException       if the requested number of bytes does
       *                                        not represent an integral number of sample frames,
       *                                        or if <code>len</code> is negative
       * @throws ArrayIndexOutOfBoundsException if <code>off</code> is negative,
       *                                        or <code>off+len</code> is greater than the length of the array
       *                                        <code>b</code>.
       * @see TargetDataLine#read
       * @see DataLine#available
       */
      int write(byte[] b, int off, int len);
  
      /**
       * Obtains the number of sample frames of audio data that can be written to
       * the mixer, via this data line, without blocking.  Note that the return
       * value measures sample frames, not bytes.
       * @return the number of sample frames currently available for writing
       * @see TargetDataLine#availableRead
       */
      //public int availableWrite();
  }
  