/* * Copyright (c) 1999, 2003, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ 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();}