Clip.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package javax.sound.sampled;

import java.io.InputStream;
import java.io.IOException;

/**
 * The <code>Clip</code> interface represents a special kind of data line whose
 * audio data can be loaded prior to playback, instead of being streamed in
 * real time.
 * <p>
 * Because the data is pre-loaded and has a known length, you can set a clip
 * to start playing at any position in its audio data.  You can also create a
 * loop, so that when the clip is played it will cycle repeatedly.  Loops are
 * specified with a starting and ending sample frame, along with the number of
 * times that the loop should be played.
 * <p>
 * Clips may be obtained from a <code>{@link Mixer}</code> that supports lines
 * of this type.  Data is loaded into a clip when it is opened.
 * <p>
 * Playback of an audio clip may be started and stopped using the <code>start</code>
 * and <code>stop</code> methods.  These methods do not reset the media position;
 * <code>start</code> causes playback to continue from the position where playback
 * was last stopped.  To restart playback from the beginning of the clip's audio
 * data, simply follow the invocation of <code>{@link DataLine#stop stop}</code>
 * with setFramePosition(0), which rewinds the media to the beginning
 * of the clip.
 *
 * @author Kara Kytle
 * @since 1.3
 */
public interface Clip extends DataLine {


    /**
     * A value indicating that looping should continue indefinitely rather than
     * complete after a specific number of loops.
     * @see #loop
     */
    public static final int LOOP_CONTINUOUSLY = -1;

    /**
     * Opens the clip, meaning that it should acquire any required
     * system resources and become operational.  The clip is opened
     * with the format and audio data indicated.
     * 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 IllegalStateException.
     * <p>
     * Note that some lines, once closed, cannot be reopened.  Attempts
     * to reopen such a line will always result in a
     * <code>{@link LineUnavailableException}</code>.
     *
     * @param format the format of the supplied audio data
     * @param data a byte array containing audio data to load into the clip
     * @param offset the point at which to start copying, expressed in
     * <em>bytes</em> from the beginning of the array
     * @param bufferSize the number of <em>bytes</em>
     * of data to load into the clip from the array.
     * @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 #close
     * @see #isOpen
     * @see LineListener
     */
    public void open(AudioFormat format, byte[] data, int offset, int bufferSize) throws LineUnavailableException;

    /**
     * Opens the clip with the format and audio data present in the provided audio
     * input stream.  Opening a clip means that it should acquire any required
     * system resources and become operational.  If this operation
     * input stream.  If this operation
     * succeeds, the line is marked 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 IllegalStateException.
     * <p>
     * Note that some lines, once closed, cannot be reopened.  Attempts
     * to reopen such a line will always result in a
     * <code>{@link LineUnavailableException}</code>.
     *
     * @param stream an audio input stream from which audio data will be read into
     * the clip
     * @throws LineUnavailableException if the line cannot be
     * opened due to resource restrictions
     * @throws IOException if an I/O exception occurs during reading of
     * the stream
     * @throws IllegalArgumentException if the stream's audio format
     * 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 #close
     * @see #isOpen
     * @see LineListener
     */
    public void open(AudioInputStream stream) throws LineUnavailableException, IOException;

    /**
     * Obtains the media length in sample frames.
     * @return the media length, expressed in sample frames,
     * or <code>AudioSystem.NOT_SPECIFIED</code> if the line is not open.
     * @see AudioSystem#NOT_SPECIFIED
     */
    public int getFrameLength();

    /**
     * Obtains the media duration in microseconds
     * @return the media duration, expressed in microseconds,
     * or <code>AudioSystem.NOT_SPECIFIED</code> if the line is not open.
     * @see AudioSystem#NOT_SPECIFIED
     */
    public long getMicrosecondLength();

    /**
     * Sets the media position in sample frames.  The position is zero-based;
     * the first frame is frame number zero.  When the clip begins playing the
     * next time, it will start by playing the frame at this position.
     * <p>
     * To obtain the current position in sample frames, use the
     * <code>{@link DataLine#getFramePosition getFramePosition}</code>
     * method of <code>DataLine</code>.
     *
     * @param frames the desired new media position, expressed in sample frames
     */
    public void setFramePosition(int frames);

    /**
     * Sets the media position in microseconds.  When the clip begins playing the
     * next time, it will start at this position.
     * The level of precision is not guaranteed.  For example, an implementation
     * might calculate the microsecond position from the current frame position
     * and the audio sample frame rate.  The precision in microseconds would
     * then be limited to the number of microseconds per sample frame.
     * <p>
     * To obtain the current position in microseconds, use the
     * <code>{@link DataLine#getMicrosecondPosition getMicrosecondPosition}</code>
     * method of <code>DataLine</code>.
     *
     * @param microseconds the desired new media position, expressed in microseconds
     */
    public void setMicrosecondPosition(long microseconds);

    /**
     * Sets the first and last sample frames that will be played in
     * the loop.  The ending point must be greater than
     * or equal to the starting point, and both must fall within the
     * the size of the loaded media.  A value of 0 for the starting
     * point means the beginning of the loaded media.  Similarly, a value of -1
     * for the ending point indicates the last frame of the media.
     * @param start the loop's starting position, in sample frames (zero-based)
     * @param end the loop's ending position, in sample frames (zero-based), or
     * -1 to indicate the final frame
     * @throws IllegalArgumentException if the requested
     * loop points cannot be set, usually because one or both falls outside
     * the media's duration or because the ending point is
     * before the starting point
     */
    public void setLoopPoints(int start, int end);

    /**
     * Starts looping playback from the current position.   Playback will
     * continue to the loop's end point, then loop back to the loop start point
     * <code>count</code> times, and finally continue playback to the end of
     * the clip.
     * <p>
     * If the current position when this method is invoked is greater than the
     * loop end point, playback simply continues to the
     * end of the clip without looping.
     * <p>
     * A <code>count</code> value of 0 indicates that any current looping should
     * cease and playback should continue to the end of the clip.  The behavior
     * is undefined when this method is invoked with any other value during a
     * loop operation.
     * <p>
     * If playback is stopped during looping, the current loop status is
     * cleared; the behavior of subsequent loop and start requests is not
     * affected by an interrupted loop operation.
     *
     * @param count the number of times playback should loop back from the
     * loop's end position to the loop's  start position, or
     * <code>{@link #LOOP_CONTINUOUSLY}</code> to indicate that looping should
     * continue until interrupted
     */
    public void loop(int count);
}