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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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 * accompanied this code).

 *

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 * 2 along with this work; if not, write to the Free Software Foundation,

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package javax.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

     */

    public 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>

     * 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

     */

    public 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

     */

    public 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();

}