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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 target data line is a type of <code>{@link DataLine}</code> from which
   * audio data can be read.  The most common example is a data line that gets
   * its data from an audio capture device.  (The device is implemented as a
   * mixer that writes to the target data line.)
   * <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 target data line may act as a source for audio data.
   * <p/>
   * The target 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>TargetDataLine</code> interface provides a method for reading the
   * captured data from the target data line's buffer.Applications
   * that record audio should read data from the target data line quickly enough
   * to keep the buffer from overflowing, which could cause discontinuities in
   * the captured data 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.  If the buffer does overflow,
   * the oldest queued data is discarded and replaced by new data.
   *
   * @author Kara Kytle
   * @see Mixer
   * @see DataLine
   * @see SourceDataLine
   * @since 1.3
   */
  public interface TargetDataLine extends DataLine {
  
  
      /**
       * Opens the line with the specified format and requested 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 that is already open is illegal
       * and may result in an <code>IllegalStateException</code>.
       * <p/>
       * 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, in bytes.
       * @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 that is already open is illegal
       * and may result in an <code>IllegalStateException</code>.
       * <p/>
       * 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;
  
  
      /**
       * 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.
       * <p/>
       * The number of bytes that can be read 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 read without blocking, there is no guarantee
       * that attempts to read additional data will block.)
       * <p/>
       * The number of bytes to be read must represent an integral number of
       * sample frames, such that:
       * <br>
       * <center><code>[ bytes read ] % [frame size in bytes ] == 0</code></center>
       * <br>
       * 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.
       *
       * @param b   a byte array that will contain the requested input data when
       *            this method returns
       * @param off the offset from the beginning of the array, in bytes
       * @param len the requested number of bytes to read
       * @return 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 <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 SourceDataLine#write
       * @see DataLine#available
       */
      int read(byte[] b, int off, int len);
  
      /**
       * Obtains the number of sample frames of audio data that can be read from
       * the target data line without blocking.  Note that the return value
       * measures sample frames, not bytes.
       * @return the number of sample frames currently available for reading
       * @see SourceDataLine#availableWrite
       */
      //public int availableRead();
  }
  