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  25 
  26 package javax.sound.midi;
  27 
  28 
  29 /**
  30  * A <code>MidiChannel</code> object represents a single MIDI channel.
  31  * Generally, each <code>MidiChannel</code> method processes a like-named MIDI
  32  * "channel voice" or "channel mode" message as defined by the MIDI specification. However,
  33  * <code>MidiChannel</code> adds some "get" methods  that retrieve the value
  34  * most recently set by one of the standard MIDI channel messages.  Similarly,
  35  * methods for per-channel solo and mute have been added.
  36  * <p>
  37  * A <code>{@link Synthesizer}</code> object has a collection
  38  * of <code>MidiChannels</code>, usually one for each of the 16 channels
  39  * prescribed by the MIDI 1.0 specification.  The <code>Synthesizer</code>
  40  * generates sound when its <code>MidiChannels</code> receive
  41  * <code>noteOn</code> messages.
  42  * <p>
  43  * See the MIDI 1.0 Specification for more information about the prescribed
  44  * behavior of the MIDI channel messages, which are not exhaustively
  45  * documented here.  The specification is titled <code>MIDI Reference:
  46  * The Complete MIDI 1.0 Detailed Specification</code>, and is published by
  47  * the MIDI Manufacturer's Association (<a href = http://www.midi.org>
  48  * http://www.midi.org</a>).
  49  * <p>
  50  * MIDI was originally a protocol for reporting the gestures of a keyboard
  51  * musician.  This genesis is visible in the <code>MidiChannel</code> API, which
  52  * preserves such MIDI concepts as key number, key velocity, and key pressure.
  53  * It should be understood that the MIDI data does not necessarily originate
  54  * with a keyboard player (the source could be a different kind of musician, or
  55  * software).  Some devices might generate constant values for velocity
  56  * and pressure, regardless of how the note was performed.
  57  * Also, the MIDI specification often leaves it up to the
  58  * synthesizer to use the data in the way the implementor sees fit.  For
  59  * example, velocity data need not always be mapped to volume and/or brightness.
  60  *
  61  * @see Synthesizer#getChannels
  62  *
  63  * @author David Rivas
  64  * @author Kara Kytle
  65  */
  66 
  67 public interface MidiChannel {
  68 
  69     /**
  70      * Starts the specified note sounding.  The key-down velocity
  71      * usually controls the note's volume and/or brightness.
  72      * If <code>velocity</code> is zero, this method instead acts like
  73      * {@link #noteOff(int)}, terminating the note.
  74      *
  75      * @param noteNumber the MIDI note number, from 0 to 127 (60 = Middle C)
  76      * @param velocity the speed with which the key was depressed
  77      *
  78      * @see #noteOff(int, int)
  79      */
  80     public void noteOn(int noteNumber, int velocity);
  81 
  82     /**
  83      * Turns the specified note off.  The key-up velocity, if not ignored, can
  84      * be used to affect how quickly the note decays.
  85      * In any case, the note might not die away instantaneously; its decay
  86      * rate is determined by the internals of the <code>Instrument</code>.
  87      * If the Hold Pedal (a controller; see
  88      * {@link #controlChange(int, int) controlChange})
  89      * is down, the effect of this method is deferred until the pedal is
  90      * released.
  91      *
  92      *
  93      * @param noteNumber the MIDI note number, from 0 to 127 (60 = Middle C)
  94      * @param velocity the speed with which the key was released
  95      *
  96      * @see #noteOff(int)
  97      * @see #noteOn
  98      * @see #allNotesOff
  99      * @see #allSoundOff
 100      */
 101     public void noteOff(int noteNumber, int velocity);
 102 
 103     /**
 104      * Turns the specified note off.
 105      *
 106      * @param noteNumber the MIDI note number, from 0 to 127 (60 = Middle C)
 107      *
 108      * @see #noteOff(int, int)
 109      */
 110     public void noteOff(int noteNumber);
 111 
 112     /**
 113      * Reacts to a change in the specified note's key pressure.
 114      * Polyphonic key pressure
 115      * allows a keyboard player to press multiple keys simultaneously, each
 116      * with a different amount of pressure.  The pressure, if not ignored,
 117      * is typically used to vary such features as the volume, brightness,
 118      * or vibrato of the note.
 119      *
 120      * It is possible that the underlying synthesizer
 121      * does not support this MIDI message. In order
 122      * to verify that <code>setPolyPressure</code>
 123      * was successful, use <code>getPolyPressure</code>.
 124      *
 125      * @param noteNumber the MIDI note number, from 0 to 127 (60 = Middle C)
 126      * @param pressure value for the specified key, from 0 to 127 (127 =
 127      * maximum pressure)
 128      *
 129      * @see #getPolyPressure(int)
 130      */
 131     public void setPolyPressure(int noteNumber, int pressure);
 132 
 133     /**
 134      * Obtains the pressure with which the specified key is being depressed.
 135      *
 136      * @param noteNumber the MIDI note number, from 0 to 127 (60 = Middle C)
 137      *
 138      * If the device does not support setting poly pressure,
 139      * this method always returns 0. Calling
 140      * <code>setPolyPressure</code> will have no effect then.
 141      *
 142      * @return the amount of pressure for that note, from 0 to 127
 143      * (127 = maximum pressure)
 144      *
 145      * @see #setPolyPressure(int, int)
 146      */
 147     public int getPolyPressure(int noteNumber);
 148 
 149     /**
 150      * Reacts to a change in the keyboard pressure.  Channel
 151      * pressure indicates how hard the keyboard player is depressing
 152      * the entire keyboard.  This can be the maximum or
 153      * average of the per-key pressure-sensor values, as set by
 154      * <code>setPolyPressure</code>.  More commonly, it is a measurement of
 155      * a single sensor on a device that doesn't implement polyphonic key
 156      * pressure.  Pressure can be used to control various aspects of the sound,
 157      * as described under {@link #setPolyPressure(int, int) setPolyPressure}.
 158      *
 159      * It is possible that the underlying synthesizer
 160      * does not support this MIDI message. In order
 161      * to verify that <code>setChannelPressure</code>
 162      * was successful, use <code>getChannelPressure</code>.
 163      *
 164      * @param pressure the pressure with which the keyboard is being depressed,
 165      * from 0 to 127 (127 = maximum pressure)
 166      * @see #setPolyPressure(int, int)
 167      * @see #getChannelPressure
 168      */
 169     public void setChannelPressure(int pressure);
 170 
 171     /**
 172      * Obtains the channel's keyboard pressure.
 173      * If the device does not support setting channel pressure,
 174      * this method always returns 0. Calling
 175      * <code>setChannelPressure</code> will have no effect then.
 176      *
 177      * @return the amount of pressure for that note,
 178      *         from 0 to 127 (127 = maximum pressure)
 179      *
 180      * @see #setChannelPressure(int)
 181      */
 182     public int getChannelPressure();
 183 
 184     /**
 185      * Reacts to a change in the specified controller's value.  A controller
 186      * is some control other than a keyboard key, such as a
 187      * switch, slider, pedal, wheel, or breath-pressure sensor.
 188      * The MIDI 1.0 Specification provides standard numbers for typical
 189      * controllers on MIDI devices, and describes the intended effect
 190      * for some of the controllers.
 191      * The way in which an
 192      * <code>Instrument</code> reacts to a controller change may be
 193      * specific to the <code>Instrument</code>.
 194      * <p>
 195      * The MIDI 1.0 Specification defines both 7-bit controllers
 196      * and 14-bit controllers.  Continuous controllers, such
 197      * as wheels and sliders, typically have 14 bits (two MIDI bytes),
 198      * while discrete controllers, such as switches, typically have 7 bits
 199      * (one MIDI byte).  Refer to the specification to see the
 200      * expected resolution for each type of control.
 201      * <p>
 202      * Controllers 64 through 95 (0x40 - 0x5F) allow 7-bit precision.
 203      * The value of a 7-bit controller is set completely by the
 204      * <code>value</code> argument.  An additional set of controllers
 205      * provide 14-bit precision by using two controller numbers, one
 206      * for the most significant 7 bits and another for the least significant
 207      * 7 bits.  Controller numbers 0 through 31 (0x00 - 0x1F) control the
 208      * most significant 7 bits of 14-bit controllers; controller numbers
 209      * 32 through 63 (0x20 - 0x3F) control the least significant 7 bits of
 210      * these controllers.  For example, controller number 7 (0x07) controls
 211      * the upper 7 bits of the channel volume controller, and controller
 212      * number 39 (0x27) controls the lower 7 bits.
 213      * The value of a 14-bit controller is determined
 214      * by the interaction of the two halves.  When the most significant 7 bits
 215      * of a controller are set (using controller numbers 0 through 31), the
 216      * lower 7 bits are automatically set to 0.  The corresponding controller
 217      * number for the lower 7 bits may then be used to further modulate the
 218      * controller value.
 219      *
 220      * It is possible that the underlying synthesizer
 221      * does not support a specific controller message. In order
 222      * to verify that a call to <code>controlChange</code>
 223      * was successful, use <code>getController</code>.
 224      *
 225      * @param controller the controller number (0 to 127; see the MIDI
 226      * 1.0 Specification for the interpretation)
 227      * @param value the value to which the specified controller is changed (0 to 127)
 228      *
 229      * @see #getController(int)
 230      */
 231     public void controlChange(int controller, int value);
 232 
 233     /**
 234      * Obtains the current value of the specified controller.  The return
 235      * value is represented with 7 bits. For 14-bit controllers, the MSB and
 236      * LSB controller value needs to be obtained separately. For example,
 237      * the 14-bit value of the volume controller can be calculated by
 238      * multiplying the value of controller 7 (0x07, channel volume MSB)
 239      * with 128 and adding the
 240      * value of controller 39 (0x27, channel volume LSB).
 241      *
 242      * If the device does not support setting a specific controller,
 243      * this method returns 0 for that controller.
 244      * Calling <code>controlChange</code> will have no effect then.
 245      *
 246      * @param controller the number of the controller whose value is desired.
 247      * The allowed range is 0-127; see the MIDI
 248      * 1.0 Specification for the interpretation.
 249      *
 250      * @return the current value of the specified controller (0 to 127)
 251      *
 252      * @see #controlChange(int, int)
 253      */
 254     public int getController(int controller);
 255 
 256     /**
 257      * Changes a program (patch).  This selects a specific
 258      * instrument from the currently selected bank of instruments.
 259      * <p>
 260      * The MIDI specification does not
 261      * dictate whether notes that are already sounding should switch
 262      * to the new instrument (timbre) or continue with their original timbre
 263      * until terminated by a note-off.
 264      * <p>
 265      * The program number is zero-based (expressed from 0 to 127).
 266      * Note that MIDI hardware displays and literature about MIDI
 267      * typically use the range 1 to 128 instead.
 268      *
 269      * It is possible that the underlying synthesizer
 270      * does not support a specific program. In order
 271      * to verify that a call to <code>programChange</code>
 272      * was successful, use <code>getProgram</code>.
 273      *
 274      * @param program the program number to switch to (0 to 127)
 275      *
 276      * @see #programChange(int, int)
 277      * @see #getProgram()
 278      */
 279     public void programChange(int program);
 280 
 281     /**
 282      * Changes the program using bank and program (patch) numbers.
 283      *
 284      * It is possible that the underlying synthesizer
 285      * does not support a specific bank, or program. In order
 286      * to verify that a call to <code>programChange</code>
 287      * was successful, use <code>getProgram</code> and
 288      * <code>getController</code>.
 289      * Since banks are changed by way of control changes,
 290      * you can verify the current bank with the following
 291      * statement:
 292      * <pre>
 293      *   int bank = (getController(0) * 128)
 294      *              + getController(32);
 295      * </pre>
 296      *
 297      * @param bank the bank number to switch to (0 to 16383)
 298      * @param program the program (patch) to use in the specified bank (0 to 127)
 299      * @see #programChange(int)
 300      * @see #getProgram()
 301      */
 302     public void programChange(int bank, int program);
 303 
 304     /**
 305      * Obtains the current program number for this channel.
 306      * @return the program number of the currently selected patch
 307      * @see Patch#getProgram
 308      * @see Synthesizer#loadInstrument
 309      * @see #programChange(int)
 310      */
 311     public int getProgram();
 312 
 313     /**
 314      * Changes the pitch offset for all notes on this channel.
 315      * This affects all currently sounding notes as well as subsequent ones.
 316      * (For pitch bend to cease, the value needs to be reset to the
 317      * center position.)
 318      * <p> The MIDI specification
 319      * stipulates that pitch bend be a 14-bit value, where zero
 320      * is maximum downward bend, 16383 is maximum upward bend, and
 321      * 8192 is the center (no pitch bend).  The actual
 322      * amount of pitch change is not specified; it can be changed by
 323      * a pitch-bend sensitivity setting.  However, the General MIDI
 324      * specification says that the default range should be two semitones
 325      * up and down from center.
 326      *
 327      * It is possible that the underlying synthesizer
 328      * does not support this MIDI message. In order
 329      * to verify that <code>setPitchBend</code>
 330      * was successful, use <code>getPitchBend</code>.
 331      *
 332      * @param bend the amount of pitch change, as a nonnegative 14-bit value
 333      * (8192 = no bend)
 334      *
 335      * @see #getPitchBend
 336      */
 337     public void setPitchBend(int bend);
 338 
 339     /**
 340      * Obtains the upward or downward pitch offset for this channel.
 341      * If the device does not support setting pitch bend,
 342      * this method always returns 8192. Calling
 343      * <code>setPitchBend</code> will have no effect then.
 344      *
 345      * @return bend amount, as a nonnegative 14-bit value (8192 = no bend)
 346      *
 347      * @see #setPitchBend(int)
 348      */
 349     public int getPitchBend();
 350 
 351     /**
 352      * Resets all the implemented controllers to their default values.
 353      *
 354      * @see #controlChange(int, int)
 355      */
 356     public void resetAllControllers();
 357 
 358     /**
 359      * Turns off all notes that are currently sounding on this channel.
 360      * The notes might not die away instantaneously; their decay
 361      * rate is determined by the internals of the <code>Instrument</code>.
 362      * If the Hold Pedal controller (see
 363      * {@link #controlChange(int, int) controlChange})
 364      * is down, the effect of this method is deferred until the pedal is
 365      * released.
 366      *
 367      * @see #allSoundOff
 368      * @see #noteOff(int)
 369      */
 370     public void allNotesOff();
 371 
 372     /**
 373      * Immediately turns off all sounding notes on this channel, ignoring the
 374      * state of the Hold Pedal and the internal decay rate of the current
 375      * <code>Instrument</code>.
 376      *
 377      * @see #allNotesOff
 378      */
 379     public void allSoundOff();
 380 
 381     /**
 382      * Turns local control on or off.  The default is for local control
 383      * to be on.  The "on" setting means that if a device is capable
 384      * of both synthesizing sound and transmitting MIDI messages,
 385      * it will synthesize sound in response to the note-on and
 386      * note-off messages that it itself transmits.  It will also respond
 387      * to messages received from other transmitting devices.
 388      * The "off" setting means that the synthesizer will ignore its
 389      * own transmitted MIDI messages, but not those received from other devices.
 390      *
 391      * It is possible that the underlying synthesizer
 392      * does not support local control. In order
 393      * to verify that a call to <code>localControl</code>
 394      * was successful, check the return value.
 395      *
 396      * @param on <code>true</code> to turn local control on, <code>false</code>
 397      *  to turn local control off
 398      * @return the new local-control value, or false
 399      *         if local control is not supported
 400      *
 401      */
 402     public boolean localControl(boolean on);
 403 
 404     /**
 405      * Turns mono mode on or off.  In mono mode, the channel synthesizes
 406      * only one note at a time.  In poly mode (identical to mono mode off),
 407      * the channel can synthesize multiple notes simultaneously.
 408      * The default is mono off (poly mode on).
 409      * <p>
 410      * "Mono" is short for the word "monophonic," which in this context
 411      * is opposed to the word "polyphonic" and refers to a single synthesizer
 412      * voice per MIDI channel.  It
 413      * has nothing to do with how many audio channels there might be
 414      * (as in "monophonic" versus "stereophonic" recordings).
 415      *
 416      * It is possible that the underlying synthesizer
 417      * does not support mono mode. In order
 418      * to verify that a call to <code>setMono</code>
 419      * was successful, use <code>getMono</code>.
 420      *
 421      * @param on <code>true</code> to turn mono mode on, <code>false</code> to
 422      * turn it off (which means turning poly mode on).
 423      *
 424      * @see #getMono
 425      * @see VoiceStatus
 426      */
 427     public void setMono(boolean on);
 428 
 429     /**
 430      * Obtains the current mono/poly mode.
 431      * Synthesizers that do not allow changing mono/poly mode
 432      * will always return the same value, regardless
 433      * of calls to <code>setMono</code>.
 434      * @return <code>true</code> if mono mode is on, otherwise
 435      * <code>false</code> (meaning poly mode is on).
 436      *
 437      * @see #setMono(boolean)
 438      */
 439     public boolean getMono();
 440 
 441     /**
 442      * Turns omni mode on or off.  In omni mode, the channel responds
 443      * to messages sent on all channels.  When omni is off, the channel
 444      * responds only to messages sent on its channel number.
 445      * The default is omni off.
 446      *
 447      * It is possible that the underlying synthesizer
 448      * does not support omni mode. In order
 449      * to verify that <code>setOmni</code>
 450      * was successful, use <code>getOmni</code>.
 451      *
 452      * @param on <code>true</code> to turn omni mode on, <code>false</code> to
 453      * turn it off.
 454      *
 455      * @see #getOmni
 456      * @see VoiceStatus
 457      */
 458     public void setOmni(boolean on);
 459 
 460     /**
 461      * Obtains the current omni mode.
 462      * Synthesizers that do not allow changing the omni mode
 463      * will always return the same value, regardless
 464      * of calls to <code>setOmni</code>.
 465      * @return <code>true</code> if omni mode is on, otherwise
 466      * <code>false</code> (meaning omni mode is off).
 467      *
 468      * @see #setOmni(boolean)
 469      */
 470     public boolean getOmni();
 471 
 472     /**
 473      * Sets the mute state for this channel. A value of
 474      * <code>true</code> means the channel is to be muted, <code>false</code>
 475      * means the channel can sound (if other channels are not soloed).
 476      * <p>
 477      * Unlike {@link #allSoundOff()}, this method
 478      * applies to only a specific channel, not to all channels.  Further, it
 479      * silences not only currently sounding notes, but also subsequently
 480      * received notes.
 481      *
 482      * It is possible that the underlying synthesizer
 483      * does not support muting channels. In order
 484      * to verify that a call to <code>setMute</code>
 485      * was successful, use <code>getMute</code>.
 486      *
 487      * @param mute the new mute state
 488      *
 489      * @see #getMute
 490      * @see #setSolo(boolean)
 491      */
 492     public void setMute(boolean mute);
 493 
 494     /**
 495      * Obtains the current mute state for this channel.
 496      * If the underlying synthesizer does not support
 497      * muting this channel, this method always returns
 498      * <code>false</code>.
 499      *
 500      * @return <code>true</code> the channel is muted,
 501      *         or <code>false</code> if not
 502      *
 503      * @see #setMute(boolean)
 504      */
 505     public boolean getMute();
 506 
 507     /**
 508      * Sets the solo state for this channel.
 509      * If <code>solo</code> is <code>true</code> only this channel
 510      * and other soloed channels will sound. If <code>solo</code>
 511      * is <code>false</code> then only other soloed channels will
 512      * sound, unless no channels are soloed, in which case all
 513      * unmuted channels will sound.
 514      *
 515      * It is possible that the underlying synthesizer
 516      * does not support solo channels. In order
 517      * to verify that a call to <code>setSolo</code>
 518      * was successful, use <code>getSolo</code>.
 519      *
 520      * @param soloState new solo state for the channel
 521      * @see #getSolo()
 522      */
 523     public void setSolo(boolean soloState);
 524 
 525     /**
 526      * Obtains the current solo state for this channel.
 527      * If the underlying synthesizer does not support
 528      * solo on this channel, this method always returns
 529      * <code>false</code>.
 530      *
 531      * @return <code>true</code> the channel is solo,
 532      *         or <code>false</code> if not
 533      *
 534      * @see #setSolo(boolean)
 535      */
 536     public boolean getSolo();
 537 }