1 /*
2 * Copyright (c) 1999, 2020, Oracle and/or its affiliates. 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle 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 *
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24 */
25
26 package javax.sound.sampled;
27
28 /**
29 * A mixer is an audio device with one or more lines. It need not be designed
30 * for mixing audio signals. A mixer that actually mixes audio has multiple
31 * input (source) lines and at least one output (target) line. The former are
32 * often instances of classes that implement {@link SourceDataLine}, and the
33 * latter, {@link TargetDataLine}. {@link Port} objects, too, are either source
34 * lines or target lines. A mixer can accept prerecorded, loopable sound as
35 * input, by having some of its source lines be instances of objects that
36 * implement the {@link Clip} interface.
37 * <p>
38 * Through methods of the {@code Line} interface, which {@code Mixer} extends, a
39 * mixer might provide a set of controls that are global to the mixer. For
40 * example, the mixer can have a master gain control. These global controls are
41 * distinct from the controls belonging to each of the mixer's individual lines.
42 * <p>
43 * Some mixers, especially those with internal digital mixing capabilities, may
44 * provide additional capabilities by implementing the {@code DataLine}
45 * interface.
46 * <p>
47 * A mixer can support synchronization of its lines. When one line in a
48 * synchronized group is started or stopped, the other lines in the group
49 * automatically start or stop simultaneously with the explicitly affected one.
50 *
51 * @author Kara Kytle
52 * @since 1.3
53 */
54 public interface Mixer extends Line {
55
56 /**
57 * Obtains information about this mixer, including the product's name,
58 * version, vendor, etc.
59 *
60 * @return a mixer info object that describes this mixer
61 * @see Info
62 */
63 Info getMixerInfo();
64
65 /**
66 * Obtains information about the set of source lines supported by this
67 * mixer. Some source lines may only be available when this mixer is open.
68 *
69 * @return array of {@code Line.Info} objects representing source lines for
70 * this mixer. If no source lines are supported, an array of length
71 * 0 is returned.
72 */
73 Line.Info[] getSourceLineInfo();
74
75 /**
76 * Obtains information about the set of target lines supported by this
77 * mixer. Some target lines may only be available when this mixer is open.
78 *
79 * @return array of {@code Line.Info} objects representing target lines for
80 * this mixer. If no target lines are supported, an array of length
81 * 0 is returned.
82 */
83 Line.Info[] getTargetLineInfo();
84
85 /**
86 * Obtains information about source lines of a particular type supported by
87 * the mixer. Some source lines may only be available when this mixer is
88 * open.
89 *
90 * @param info a {@code Line.Info} object describing lines about which
91 * information is queried
92 * @return an array of {@code Line.Info} objects describing source lines
93 * matching the type requested. If no matching source lines are
94 * supported, an array of length 0 is returned.
95 */
96 Line.Info[] getSourceLineInfo(Line.Info info);
97
98 /**
99 * Obtains information about target lines of a particular type supported by
100 * the mixer. Some target lines may only be available when this mixer is
101 * open.
102 *
103 * @param info a {@code Line.Info} object describing lines about which
104 * information is queried
105 * @return an array of {@code Line.Info} objects describing target lines
106 * matching the type requested. If no matching target lines are
107 * supported, an array of length 0 is returned.
108 */
109 Line.Info[] getTargetLineInfo(Line.Info info);
110
111 /**
112 * Indicates whether the mixer supports a line (or lines) that match the
113 * specified {@code Line.Info} object. Some lines may only be supported when
114 * this mixer is open.
115 *
116 * @param info describes the line for which support is queried
117 * @return {@code true} if at least one matching line is supported,
118 * {@code false} otherwise
119 */
120 boolean isLineSupported(Line.Info info);
121
122 /**
123 * Obtains a line that is available for use and that matches the description
124 * in the specified {@code Line.Info} object.
125 * <p>
126 * If a {@code DataLine} is requested, and {@code info} is an instance of
127 * {@code DataLine.Info} specifying at least one fully qualified audio
128 * format, the last one will be used as the default format of the returned
129 * {@code DataLine}.
130 *
131 * @param info describes the desired line
132 * @return a line that is available for use and that matches the description
133 * in the specified {@code Line.Info} object
134 * @throws LineUnavailableException if a matching line is not available due
135 * to resource restrictions
136 * @throws IllegalArgumentException if this mixer does not support any lines
137 * matching the description
138 * @throws SecurityException if a matching line is not available due to
139 * security restrictions
140 */
141 Line getLine(Line.Info info) throws LineUnavailableException;
142
143 //$$fb 2002-04-12: fix for 4667258: behavior of Mixer.getMaxLines(Line.Info) method doesn't match the spec
144 /**
145 * Obtains the approximate maximum number of lines of the requested type
146 * that can be open simultaneously on the mixer.
147 * <p>
148 * Certain types of mixers do not have a hard bound and may allow opening
149 * more lines. Since certain lines are a shared resource, a mixer may not be
150 * able to open the maximum number of lines if another process has opened
151 * lines of this mixer.
152 * <p>
153 * The requested type is any line that matches the description in the
154 * provided {@code Line.Info} object. For example, if the info object
155 * represents a speaker port, and the mixer supports exactly one speaker
156 * port, this method should return 1. If the info object represents a source
157 * data line and the mixer supports the use of 32 source data lines
158 * simultaneously, the return value should be 32. If there is no limit, this
159 * function returns {@link AudioSystem#NOT_SPECIFIED}.
160 *
161 * @param info a {@code Line.Info} that describes the line for which the
162 * number of supported instances is queried
163 * @return the maximum number of matching lines supported, or
164 * {@code AudioSystem.NOT_SPECIFIED}
165 */
166 int getMaxLines(Line.Info info);
167
168 /**
169 * Obtains the set of all source lines currently open to this mixer.
170 *
171 * @return the source lines currently open to the mixer. If no source lines
172 * are currently open to this mixer, an array of length 0 is
173 * returned.
174 * @throws SecurityException if the matching lines are not available due to
175 * security restrictions
176 */
177 Line[] getSourceLines();
178
179 /**
180 * Obtains the set of all target lines currently open from this mixer.
181 *
182 * @return target lines currently open from the mixer. If no target lines
183 * are currently open from this mixer, an array of length 0 is
184 * returned.
185 * @throws SecurityException if the matching lines are not available due to
186 * security restrictions
187 */
188 Line[] getTargetLines();
189
190 /**
191 * Synchronizes two or more lines. Any subsequent command that starts or
192 * stops audio playback or capture for one of these lines will exert the
193 * same effect on the other lines in the group, so that they start or stop
194 * playing or capturing data simultaneously.
195 *
196 * @param lines the lines that should be synchronized
197 * @param maintainSync {@code true} if the synchronization must be
198 * precisely maintained (i.e., the synchronization must be
199 * sample-accurate) at all times during operation of the lines, or
200 * {@code false} if precise synchronization is required only during
201 * start and stop operations
202 * @throws IllegalArgumentException if the lines cannot be synchronized.
203 * This may occur if the lines are of different types or have
204 * different formats for which this mixer does not support
205 * synchronization, or if all lines specified do not belong to this
206 * mixer.
207 */
208 void synchronize(Line[] lines, boolean maintainSync);
209
210 /**
211 * Releases synchronization for the specified lines. The array must be
212 * identical to one for which synchronization has already been established;
213 * otherwise an exception may be thrown. However, {@code null} may be
214 * specified, in which case all currently synchronized lines that belong to
215 * this mixer are unsynchronized.
216 *
217 * @param lines the synchronized lines for which synchronization should be
218 * released, or {@code null} for all this mixer's synchronized lines
219 * @throws IllegalArgumentException if the lines cannot be unsynchronized.
220 * This may occur if the argument specified does not exactly match a
221 * set of lines for which synchronization has already been
222 * established.
223 */
224 void unsynchronize(Line[] lines);
225
226 /**
227 * Reports whether this mixer supports synchronization of the specified set
228 * of lines.
229 *
230 * @param lines the set of lines for which synchronization support is
231 * queried
232 * @param maintainSync {@code true} if the synchronization must be
233 * precisely maintained (i.e., the synchronization must be
234 * sample-accurate) at all times during operation of the lines, or
235 * {@code false} if precise synchronization is required only during
236 * start and stop operations
237 * @return {@code true} if the lines can be synchronized, {@code false}
238 * otherwise
239 */
240 boolean isSynchronizationSupported(Line[] lines, boolean maintainSync);
241
242 /**
243 * The {@code Mixer.Info} class represents information about an audio mixer,
244 * including the product's name, version, and vendor, along with a textual
245 * description. This information may be retrieved through the
246 * {@link Mixer#getMixerInfo() getMixerInfo} method of the {@code Mixer}
247 * interface.
248 *
249 * @author Kara Kytle
250 * @since 1.3
251 */
252 class Info {
253
254 /**
255 * Mixer name.
256 */
257 private final String name;
258
259 /**
260 * Mixer vendor.
261 */
262 private final String vendor;
263
264 /**
265 * Mixer description.
266 */
267 private final String description;
268
269 /**
270 * Mixer version.
271 */
272 private final String version;
273
274 /**
275 * Constructs a mixer's info object, passing it the given textual
276 * information.
277 *
278 * @param name the name of the mixer
279 * @param vendor the company who manufactures or creates the hardware
280 * or software mixer
281 * @param description descriptive text about the mixer
282 * @param version version information for the mixer
283 */
284 protected Info(String name, String vendor, String description, String version) {
285
286 this.name = name;
287 this.vendor = vendor;
288 this.description = description;
289 this.version = version;
290 }
291
292 /**
293 * Indicates whether the specified object is equal to this info object,
294 * returning {@code true} if the objects are the same.
295 *
296 * @param obj the reference object with which to compare
297 * @return {@code true} if the specified object is equal to this info
298 * object; {@code false} otherwise
299 */
300 @Override
301 public final boolean equals(Object obj) {
302 return super.equals(obj);
303 }
304
305 /**
306 * Returns a hash code value for this info object.
307 *
308 * @return a hash code value for this info object
309 */
310 @Override
311 public final int hashCode() {
312 return super.hashCode();
313 }
314
315 /**
316 * Obtains the name of the mixer.
317 *
318 * @return a string that names the mixer
319 */
320 public final String getName() {
321 return name;
322 }
323
324 /**
325 * Obtains the vendor of the mixer.
326 *
327 * @return a string that names the mixer's vendor
328 */
329 public final String getVendor() {
330 return vendor;
331 }
332
333 /**
334 * Obtains the description of the mixer.
335 *
336 * @return a textual description of the mixer
337 */
338 public final String getDescription() {
339 return description;
340 }
341
342 /**
343 * Obtains the version of the mixer.
344 *
345 * @return textual version information for the mixer
346 */
347 public final String getVersion() {
348 return version;
349 }
350
351 /**
352 * Returns a string representation of the info object.
353 *
354 * @return a string representation of the info object
355 */
356 @Override
357 public final String toString() {
358 return String.format("%s, version %s", name, version);
359 }
360 }
361 }