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package javax.sound.midi;
/**
* A {@code MidiChannel} object represents a single MIDI channel. Generally,
* each {@code MidiChannel} method processes a like-named MIDI "channel voice"
* or "channel mode" message as defined by the MIDI specification. However,
* {@code MidiChannel} adds some "get" methods that retrieve the value most
* recently set by one of the standard MIDI channel messages. Similarly, methods
* for per-channel solo and mute have been added.
* <p>
* A {@link Synthesizer} object has a collection of {@code MidiChannels},
* usually one for each of the 16 channels prescribed by the MIDI 1.0
* specification. The {@code Synthesizer} generates sound when its
* {@code MidiChannels} receive {@code noteOn} messages.
* <p>
* See the MIDI 1.0 Specification for more information about the prescribed
* behavior of the MIDI channel messages, which are not exhaustively documented
* here. The specification is titled
* {@code MIDI Reference: The Complete MIDI 1.0 Detailed Specification}, and is
* published by the MIDI Manufacturer's Association
* (<a href = http://www.midi.org>http://www.midi.org</a>).
* <p>
* MIDI was originally a protocol for reporting the gestures of a keyboard
* musician. This genesis is visible in the {@code MidiChannel} API, which
* preserves such MIDI concepts as key number, key velocity, and key pressure.
* It should be understood that the MIDI data does not necessarily originate
* with a keyboard player (the source could be a different kind of musician, or
* software). Some devices might generate constant values for velocity and
* pressure, regardless of how the note was performed. Also, the MIDI
* specification often leaves it up to the synthesizer to use the data in the
* way the implementor sees fit. For example, velocity data need not always be
* mapped to volume and/or brightness.
*
* @author David Rivas
* @author Kara Kytle
* @see Synthesizer#getChannels
*/
public interface MidiChannel {
/**
* Starts the specified note sounding. The key-down velocity usually
* controls the note's volume and/or brightness. If {@code velocity} is
* zero, this method instead acts like {@link #noteOff(int)}, terminating
* the note.
*
* @param noteNumber the MIDI note number, from 0 to 127 (60 = Middle C)
* @param velocity the speed with which the key was depressed
* @see #noteOff(int, int)
*/
void noteOn(int noteNumber, int velocity);
/**
* Turns the specified note off. The key-up velocity, if not ignored, can be
* used to affect how quickly the note decays. In any case, the note might
* not die away instantaneously; its decay rate is determined by the
* internals of the {@code Instrument}. If the Hold Pedal (a controller; see
* {@link #controlChange(int, int) controlChange}) is down, the effect of
* this method is deferred until the pedal is released.
*
* @param noteNumber the MIDI note number, from 0 to 127 (60 = Middle C)
* @param velocity the speed with which the key was released
* @see #noteOff(int)
* @see #noteOn
* @see #allNotesOff
* @see #allSoundOff
*/
void noteOff(int noteNumber, int velocity);
/**
* Turns the specified note off.
*
* @param noteNumber the MIDI note number, from 0 to 127 (60 = Middle C)
* @see #noteOff(int, int)
*/
void noteOff(int noteNumber);
/**
* Reacts to a change in the specified note's key pressure. Polyphonic key
* pressure allows a keyboard player to press multiple keys simultaneously,
* each with a different amount of pressure. The pressure, if not ignored,
* is typically used to vary such features as the volume, brightness, or
* vibrato of the note.
* <p>
* It is possible that the underlying synthesizer does not support this MIDI
* message. In order to verify that {@code setPolyPressure} was successful,
* use {@code getPolyPressure}.
*
* @param noteNumber the MIDI note number, from 0 to 127 (60 = Middle C)
* @param pressure value for the specified key, from 0 to 127
* (127 = maximum pressure)
* @see #getPolyPressure(int)
*/
void setPolyPressure(int noteNumber, int pressure);
/**
* Obtains the pressure with which the specified key is being depressed.
* <p>
* If the device does not support setting poly pressure, this method always
* returns 0. Calling {@code setPolyPressure} will have no effect then.
*
* @param noteNumber the MIDI note number, from 0 to 127 (60 = Middle C)
* @return the amount of pressure for that note, from 0 to 127
* (127 = maximum pressure)
* @see #setPolyPressure(int, int)
*/
int getPolyPressure(int noteNumber);
/**
* Reacts to a change in the keyboard pressure. Channel pressure indicates
* how hard the keyboard player is depressing the entire keyboard. This can
* be the maximum or average of the per-key pressure-sensor values, as set
* by {@code setPolyPressure}. More commonly, it is a measurement of a
* single sensor on a device that doesn't implement polyphonic key pressure.
* Pressure can be used to control various aspects of the sound, as
* described under {@link #setPolyPressure(int, int) setPolyPressure}.
* <p>
* It is possible that the underlying synthesizer does not support this MIDI
* message. In order to verify that {@code setChannelPressure} was
* successful, use {@code getChannelPressure}.
*
* @param pressure the pressure with which the keyboard is being depressed,
* from 0 to 127 (127 = maximum pressure)
* @see #setPolyPressure(int, int)
* @see #getChannelPressure
*/
void setChannelPressure(int pressure);
/**
* Obtains the channel's keyboard pressure.
* <p>
* If the device does not support setting channel pressure, this method
* always returns 0. Calling {@code setChannelPressure} will have no effect
* then.
*
* @return the amount of pressure for that note, from 0 to 127
* (127 = maximum pressure)
* @see #setChannelPressure(int)
*/
int getChannelPressure();
/**
* Reacts to a change in the specified controller's value. A controller is
* some control other than a keyboard key, such as a switch, slider, pedal,
* wheel, or breath-pressure sensor. The MIDI 1.0 Specification provides
* standard numbers for typical controllers on MIDI devices, and describes
* the intended effect for some of the controllers. The way in which an
* {@code Instrument} reacts to a controller change may be specific to the
* {@code Instrument}.
* <p>
* The MIDI 1.0 Specification defines both 7-bit controllers and 14-bit
* controllers. Continuous controllers, such as wheels and sliders,
* typically have 14 bits (two MIDI bytes), while discrete controllers, such
* as switches, typically have 7 bits (one MIDI byte). Refer to the
* specification to see the expected resolution for each type of control.
* <p>
* Controllers 64 through 95 (0x40 - 0x5F) allow 7-bit precision. The value
* of a 7-bit controller is set completely by the {@code value} argument. An
* additional set of controllers provide 14-bit precision by using two
* controller numbers, one for the most significant 7 bits and another for
* the least significant 7 bits. Controller numbers 0 through 31
* (0x00 - 0x1F) control the most significant 7 bits of 14-bit controllers;
* controller numbers 32 through 63 (0x20 - 0x3F) control the least
* significant 7 bits of these controllers. For example, controller number 7
* (0x07) controls the upper 7 bits of the channel volume controller, and
* controller number 39 (0x27) controls the lower 7 bits. The value of a
* 14-bit controller is determined by the interaction of the two halves.
* When the most significant 7 bits of a controller are set (using
* controller numbers 0 through 31), the lower 7 bits are automatically set
* to 0. The corresponding controller number for the lower 7 bits may then
* be used to further modulate the controller value.
* <p>
* It is possible that the underlying synthesizer does not support a
* specific controller message. In order to verify that a call to
* {@code controlChange} was successful, use {@code getController}.
*
* @param controller the controller number (0 to 127; see the MIDI 1.0
* Specification for the interpretation)
* @param value the value to which the specified controller is changed
* (0 to 127)
* @see #getController(int)
*/
void controlChange(int controller, int value);
/**
* Obtains the current value of the specified controller. The return value
* is represented with 7 bits. For 14-bit controllers, the MSB and LSB
* controller value needs to be obtained separately. For example, the 14-bit
* value of the volume controller can be calculated by multiplying the value
* of controller 7 (0x07, channel volume MSB) with 128 and adding the value
* of controller 39 (0x27, channel volume LSB).
* <p>
* If the device does not support setting a specific controller, this method
* returns 0 for that controller. Calling {@code controlChange} will have no
* effect then.
*
* @param controller the number of the controller whose value is desired.
* The allowed range is 0-127; see the MIDI 1.0 Specification for
* the interpretation.
* @return the current value of the specified controller (0 to 127)
* @see #controlChange(int, int)
*/
int getController(int controller);
/**
* Changes a program (patch). This selects a specific instrument from the
* currently selected bank of instruments.
* <p>
* The MIDI specification does not dictate whether notes that are already
* sounding should switch to the new instrument (timbre) or continue with
* their original timbre until terminated by a note-off.
* <p>
* The program number is zero-based (expressed from 0 to 127). Note that
* MIDI hardware displays and literature about MIDI typically use the range
* 1 to 128 instead.
* <p>
* It is possible that the underlying synthesizer does not support a
* specific program. In order to verify that a call to {@code programChange}
* was successful, use {@code getProgram}.
*
* @param program the program number to switch to (0 to 127)
* @see #programChange(int, int)
* @see #getProgram()
*/
void programChange(int program);
/**
* Changes the program using bank and program (patch) numbers.
* <p>
* It is possible that the underlying synthesizer does not support a
* specific bank, or program. In order to verify that a call to
* {@code programChange} was successful, use {@code getProgram} and
* {@code getController}. Since banks are changed by way of control changes,
* you can verify the current bank with the following statement:
* <pre>
* int bank = (getController(0) * 128) + getController(32);
* </pre>
*
* @param bank the bank number to switch to (0 to 16383)
* @param program the program (patch) to use in the specified bank
* (0 to 127)
* @see #programChange(int)
* @see #getProgram()
*/
void programChange(int bank, int program);
/**
* Obtains the current program number for this channel.
*
* @return the program number of the currently selected patch
* @see Patch#getProgram
* @see Synthesizer#loadInstrument
* @see #programChange(int)
*/
int getProgram();
/**
* Changes the pitch offset for all notes on this channel. This affects all
* currently sounding notes as well as subsequent ones. (For pitch bend to
* cease, the value needs to be reset to the center position.)
* <p>
* The MIDI specification stipulates that pitch bend be a 14-bit value,
* where zero is maximum downward bend, 16383 is maximum upward bend, and
* 8192 is the center (no pitch bend). The actual amount of pitch change is
* not specified; it can be changed by a pitch-bend sensitivity setting.
* However, the General MIDI specification says that the default range
* should be two semitones up and down from center.
* <p>
* It is possible that the underlying synthesizer does not support this MIDI
* message. In order to verify that {@code setPitchBend} was successful, use
* {@code getPitchBend}.
*
* @param bend the amount of pitch change, as a nonnegative 14-bit value
* (8192 = no bend)
* @see #getPitchBend
*/
void setPitchBend(int bend);
/**
* Obtains the upward or downward pitch offset for this channel. If the
* device does not support setting pitch bend, this method always returns
* 8192. Calling {@code setPitchBend} will have no effect then.
*
* @return bend amount, as a nonnegative 14-bit value (8192 = no bend)
* @see #setPitchBend(int)
*/
int getPitchBend();
/**
* Resets all the implemented controllers to their default values.
*
* @see #controlChange(int, int)
*/
void resetAllControllers();
/**
* Turns off all notes that are currently sounding on this channel. The
* notes might not die away instantaneously; their decay rate is determined
* by the internals of the {@code Instrument}. If the Hold Pedal controller
* (see {@link #controlChange(int, int) controlChange}) is down, the effect
* of this method is deferred until the pedal is released.
*
* @see #allSoundOff
* @see #noteOff(int)
*/
void allNotesOff();
/**
* Immediately turns off all sounding notes on this channel, ignoring the
* state of the Hold Pedal and the internal decay rate of the current
* {@code Instrument}.
*
* @see #allNotesOff
*/
void allSoundOff();
/**
* Turns local control on or off. The default is for local control to be on.
* The "on" setting means that if a device is capable of both synthesizing
* sound and transmitting MIDI messages, it will synthesize sound in
* response to the note-on and note-off messages that it itself transmits.
* It will also respond to messages received from other transmitting
* devices. The "off" setting means that the synthesizer will ignore its own
* transmitted MIDI messages, but not those received from other devices.
* <p>
* It is possible that the underlying synthesizer does not support local
* control. In order to verify that a call to {@code localControl} was
* successful, check the return value.
*
* @param on {@code true} to turn local control on, {@code false} to turn
* local control off
* @return the new local-control value, or false if local control is not
* supported
*/
boolean localControl(boolean on);
/**
* Turns mono mode on or off. In mono mode, the channel synthesizes only one
* note at a time. In poly mode (identical to mono mode off), the channel
* can synthesize multiple notes simultaneously. The default is mono off
* (poly mode on).
* <p>
* "Mono" is short for the word "monophonic," which in this context is
* opposed to the word "polyphonic" and refers to a single synthesizer voice
* per MIDI channel. It has nothing to do with how many audio channels there
* might be (as in "monophonic" versus "stereophonic" recordings).
* <p>
* It is possible that the underlying synthesizer does not support mono
* mode. In order to verify that a call to {@code setMono} was successful,
* use {@code getMono}.
*
* @param on {@code true} to turn mono mode on, {@code false} to turn it
* off (which means turning poly mode on)
* @see #getMono
* @see VoiceStatus
*/
void setMono(boolean on);
/**
* Obtains the current mono/poly mode. Synthesizers that do not allow
* changing mono/poly mode will always return the same value, regardless of
* calls to {@code setMono}.
*
* @return {@code true} if mono mode is on, otherwise {@code false} (meaning
* poly mode is on)
* @see #setMono(boolean)
*/
boolean getMono();
/**
* Turns omni mode on or off. In omni mode, the channel responds to messages
* sent on all channels. When omni is off, the channel responds only to
* messages sent on its channel number. The default is omni off.
* <p>
* It is possible that the underlying synthesizer does not support omni
* mode. In order to verify that {@code setOmni} was successful, use
* {@code getOmni}.
*
* @param on {@code true} to turn omni mode on, {@code false} to turn it
* off
* @see #getOmni
* @see VoiceStatus
*/
void setOmni(boolean on);
/**
* Obtains the current omni mode. Synthesizers that do not allow changing
* the omni mode will always return the same value, regardless of calls to
* {@code setOmni}.
*
* @return {@code true} if omni mode is on, otherwise {@code false} (meaning
* omni mode is off)
* @see #setOmni(boolean)
*/
boolean getOmni();
/**
* Sets the mute state for this channel. A value of {@code true} means the
* channel is to be muted, {@code false} means the channel can sound (if
* other channels are not soloed).
* <p>
* Unlike {@link #allSoundOff()}, this method applies to only a specific
* channel, not to all channels. Further, it silences not only currently
* sounding notes, but also subsequently received notes.
* <p>
* It is possible that the underlying synthesizer does not support muting
* channels. In order to verify that a call to {@code setMute} was
* successful, use {@code getMute}.
*
* @param mute the new mute state
* @see #getMute
* @see #setSolo(boolean)
*/
void setMute(boolean mute);
/**
* Obtains the current mute state for this channel. If the underlying
* synthesizer does not support muting this channel, this method always
* returns {@code false}.
*
* @return {@code true} the channel is muted, or {@code false} if not
* @see #setMute(boolean)
*/
boolean getMute();
/**
* Sets the solo state for this channel. If {@code solo} is {@code true}
* only this channel and other soloed channels will sound. If {@code solo}
* is {@code false} then only other soloed channels will sound, unless no
* channels are soloed, in which case all unmuted channels will sound.
* <p>
* It is possible that the underlying synthesizer does not support solo
* channels. In order to verify that a call to {@code setSolo} was
* successful, use {@code getSolo}.
*
* @param soloState new solo state for the channel
* @see #getSolo()
*/
void setSolo(boolean soloState);
/**
* Obtains the current solo state for this channel. If the underlying
* synthesizer does not support solo on this channel, this method always
* returns {@code false}.
*
* @return {@code true} the channel is solo, or {@code false} if not
* @see #setSolo(boolean)
*/
boolean getSolo();
}