1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
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  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).
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  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          * Provides a string representation of the mixer info.
 353          *
 354          * @return a string describing the info object
 355          */
 356         @Override
 357         public final String toString() {
 358             return (name + ", version " + version);
 359         }
 360     }
 361 }