/* * 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 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     */    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 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     */    public 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     */    public 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();}