J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1999-2003 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package javax.sound.sampled; |
| 27 | |
| 28 | /** |
| 29 | * A target data line is a type of <code>{@link DataLine}</code> from which |
| 30 | * audio data can be read. The most common example is a data line that gets |
| 31 | * its data from an audio capture device. (The device is implemented as a |
| 32 | * mixer that writes to the target data line.) |
| 33 | * <p> |
| 34 | * Note that the naming convention for this interface reflects the relationship |
| 35 | * between the line and its mixer. From the perspective of an application, |
| 36 | * a target data line may act as a source for audio data. |
| 37 | * <p> |
| 38 | * The target data line can be obtained from a mixer by invoking the |
| 39 | * <code>{@link Mixer#getLine getLine}</code> |
| 40 | * method of <code>Mixer</code> with an appropriate |
| 41 | * <code>{@link DataLine.Info}</code> object. |
| 42 | * <p> |
| 43 | * The <code>TargetDataLine</code> interface provides a method for reading the |
| 44 | * captured data from the target data line's buffer.Applications |
| 45 | * that record audio should read data from the target data line quickly enough |
| 46 | * to keep the buffer from overflowing, which could cause discontinuities in |
| 47 | * the captured data that are perceived as clicks. Applications can use the |
| 48 | * <code>{@link DataLine#available available}</code> method defined in the |
| 49 | * <code>DataLine</code> interface to determine the amount of data currently |
| 50 | * queued in the data line's buffer. If the buffer does overflow, |
| 51 | * the oldest queued data is discarded and replaced by new data. |
| 52 | * |
| 53 | * @author Kara Kytle |
| 54 | * @see Mixer |
| 55 | * @see DataLine |
| 56 | * @see SourceDataLine |
| 57 | * @since 1.3 |
| 58 | */ |
| 59 | public interface TargetDataLine extends DataLine { |
| 60 | |
| 61 | |
| 62 | /** |
| 63 | * Opens the line with the specified format and requested buffer size, |
| 64 | * causing the line to acquire any required system resources and become |
| 65 | * operational. |
| 66 | * <p> |
| 67 | * The buffer size is specified in bytes, but must represent an integral |
| 68 | * number of sample frames. Invoking this method with a requested buffer |
| 69 | * size that does not meet this requirement may result in an |
| 70 | * IllegalArgumentException. The actual buffer size for the open line may |
| 71 | * differ from the requested buffer size. The value actually set may be |
| 72 | * queried by subsequently calling <code>{@link DataLine#getBufferSize}</code> |
| 73 | * <p> |
| 74 | * If this operation succeeds, the line is marked as open, and an |
| 75 | * <code>{@link LineEvent.Type#OPEN OPEN}</code> event is dispatched to the |
| 76 | * line's listeners. |
| 77 | * <p> |
| 78 | * Invoking this method on a line that is already open is illegal |
| 79 | * and may result in an <code>IllegalStateException</code>. |
| 80 | * <p> |
| 81 | * Some lines, once closed, cannot be reopened. Attempts |
| 82 | * to reopen such a line will always result in a |
| 83 | * <code>LineUnavailableException</code>. |
| 84 | * |
| 85 | * @param format the desired audio format |
| 86 | * @param bufferSize the desired buffer size, in bytes. |
| 87 | * @throws LineUnavailableException if the line cannot be |
| 88 | * opened due to resource restrictions |
| 89 | * @throws IllegalArgumentException if the buffer size does not represent |
| 90 | * an integral number of sample frames, |
| 91 | * or if <code>format</code> is not fully specified or invalid |
| 92 | * @throws IllegalStateException if the line is already open |
| 93 | * @throws SecurityException if the line cannot be |
| 94 | * opened due to security restrictions |
| 95 | * |
| 96 | * @see #open(AudioFormat) |
| 97 | * @see Line#open |
| 98 | * @see Line#close |
| 99 | * @see Line#isOpen |
| 100 | * @see LineEvent |
| 101 | */ |
| 102 | public void open(AudioFormat format, int bufferSize) throws LineUnavailableException; |
| 103 | |
| 104 | |
| 105 | /** |
| 106 | * Opens the line with the specified format, causing the line to acquire any |
| 107 | * required system resources and become operational. |
| 108 | * |
| 109 | * <p> |
| 110 | * The implementation chooses a buffer size, which is measured in bytes but |
| 111 | * which encompasses an integral number of sample frames. The buffer size |
| 112 | * that the system has chosen may be queried by subsequently calling <code>{@link DataLine#getBufferSize}</code> |
| 113 | * <p> |
| 114 | * If this operation succeeds, the line is marked as open, and an |
| 115 | * <code>{@link LineEvent.Type#OPEN OPEN}</code> event is dispatched to the |
| 116 | * line's listeners. |
| 117 | * <p> |
| 118 | * Invoking this method on a line that is already open is illegal |
| 119 | * and may result in an <code>IllegalStateException</code>. |
| 120 | * <p> |
| 121 | * Some lines, once closed, cannot be reopened. Attempts |
| 122 | * to reopen such a line will always result in a |
| 123 | * <code>LineUnavailableException</code>. |
| 124 | * |
| 125 | * @param format the desired audio format |
| 126 | * @throws LineUnavailableException if the line cannot be |
| 127 | * opened due to resource restrictions |
| 128 | * @throws IllegalArgumentException if <code>format</code> |
| 129 | * is not fully specified or invalid |
| 130 | * @throws IllegalStateException if the line is already open |
| 131 | * @throws SecurityException if the line cannot be |
| 132 | * opened due to security restrictions |
| 133 | * |
| 134 | * @see #open(AudioFormat, int) |
| 135 | * @see Line#open |
| 136 | * @see Line#close |
| 137 | * @see Line#isOpen |
| 138 | * @see LineEvent |
| 139 | */ |
| 140 | public void open(AudioFormat format) throws LineUnavailableException; |
| 141 | |
| 142 | |
| 143 | /** |
| 144 | * Reads audio data from the data line's input buffer. The requested |
| 145 | * number of bytes is read into the specified array, starting at |
| 146 | * the specified offset into the array in bytes. This method blocks until |
| 147 | * the requested amount of data has been read. However, if the data line |
| 148 | * is closed, stopped, drained, or flushed before the requested amount has |
| 149 | * been read, the method no longer blocks, but returns the number of bytes |
| 150 | * read thus far. |
| 151 | * <p> |
| 152 | * The number of bytes that can be read without blocking can be ascertained |
| 153 | * using the <code>{@link DataLine#available available}</code> method of the |
| 154 | * <code>DataLine</code> interface. (While it is guaranteed that |
| 155 | * this number of bytes can be read without blocking, there is no guarantee |
| 156 | * that attempts to read additional data will block.) |
| 157 | * <p> |
| 158 | * The number of bytes to be read must represent an integral number of |
| 159 | * sample frames, such that: |
| 160 | * <br> |
| 161 | * <center><code>[ bytes read ] % [frame size in bytes ] == 0</code></center> |
| 162 | * <br> |
| 163 | * The return value will always meet this requirement. A request to read a |
| 164 | * number of bytes representing a non-integral number of sample frames cannot |
| 165 | * be fulfilled and may result in an IllegalArgumentException. |
| 166 | * |
| 167 | * @param b a byte array that will contain the requested input data when |
| 168 | * this method returns |
| 169 | * @param off the offset from the beginning of the array, in bytes |
| 170 | * @param len the requested number of bytes to read |
| 171 | * @return the number of bytes actually read |
| 172 | * @throws IllegalArgumentException if the requested number of bytes does |
| 173 | * not represent an integral number of sample frames. |
| 174 | * or if <code>len</code> is negative. |
| 175 | * @throws ArrayIndexOutOfBoundsException if <code>off</code> is negative, |
| 176 | * or <code>off+len</code> is greater than the length of the array |
| 177 | * <code>b</code>. |
| 178 | * |
| 179 | * @see SourceDataLine#write |
| 180 | * @see DataLine#available |
| 181 | */ |
| 182 | public int read(byte[] b, int off, int len); |
| 183 | |
| 184 | /** |
| 185 | * Obtains the number of sample frames of audio data that can be read from |
| 186 | * the target data line without blocking. Note that the return value |
| 187 | * measures sample frames, not bytes. |
| 188 | * @return the number of sample frames currently available for reading |
| 189 | * @see SourceDataLine#availableWrite |
| 190 | */ |
| 191 | //public int availableRead(); |
| 192 | } |