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package javax.sound.midi;


A Synthesizer generates sound. This usually happens when one of the Synthesizer's MidiChannel objects receives a noteOn message, either directly or via the Synthesizer object. Many Synthesizers support Receivers, through which MIDI events can be delivered to the Synthesizer. In such cases, the Synthesizer typically responds by sending a corresponding message to the appropriate MidiChannel, or by processing the event itself if the event isn't one of the MIDI channel messages. 
 The Synthesizer interface includes methods for loading and unloading instruments from soundbanks. An instrument is a specification for synthesizing a certain type of sound, whether that sound emulates a traditional instrument or is some kind of sound effect or other imaginary sound. A soundbank is a collection of instruments, organized by bank and program number (via the instrument's Patch object). Different Synthesizer classes might implement different sound-synthesis techniques, meaning that some instruments and not others might be compatible with a given synthesizer. Also, synthesizers may have a limited amount of memory for instruments, meaning that not every soundbank and instrument can be used by every synthesizer, even if the synthesis technique is compatible. To see whether the instruments from a certain soundbank can be played by a given synthesizer, invoke the isSoundbankSupported method of Synthesizer. 
 "Loading" an instrument means that that instrument becomes available for synthesizing notes. The instrument is loaded into the bank and program location specified by its Patch object. Loading does not necessarily mean that subsequently played notes will immediately have the sound of this newly loaded instrument. For the instrument to play notes, one of the synthesizer's MidiChannel objects must receive (or have received) a program-change message that causes that particular instrument's bank and program number to be selected. 
Author:Kara Kytle
See Also:
/**
 * A {@code Synthesizer} generates sound. This usually happens when one of the
 * {@code Synthesizer}'s {@link MidiChannel} objects receives a
 * {@link MidiChannel#noteOn(int, int) noteOn} message, either directly or via
 * the {@code Synthesizer} object. Many {@code Synthesizer}s support
 * {@code Receivers}, through which MIDI events can be delivered to the
 * {@code Synthesizer}. In such cases, the {@code Synthesizer} typically
 * responds by sending a corresponding message to the appropriate
 * {@code MidiChannel}, or by processing the event itself if the event isn't one
 * of the MIDI channel messages.
 * <p>
 * The {@code Synthesizer} interface includes methods for loading and unloading
 * instruments from soundbanks. An instrument is a specification for
 * synthesizing a certain type of sound, whether that sound emulates a
 * traditional instrument or is some kind of sound effect or other imaginary
 * sound. A soundbank is a collection of instruments, organized by bank and
 * program number (via the instrument's {@code Patch} object). Different
 * {@code Synthesizer} classes might implement different sound-synthesis
 * techniques, meaning that some instruments and not others might be compatible
 * with a given synthesizer. Also, synthesizers may have a limited amount of
 * memory for instruments, meaning that not every soundbank and instrument can
 * be used by every synthesizer, even if the synthesis technique is compatible.
 * To see whether the instruments from a certain soundbank can be played by a
 * given synthesizer, invoke the
 * {@link #isSoundbankSupported(Soundbank) isSoundbankSupported} method of
 * {@code Synthesizer}.
 * <p>
 * "Loading" an instrument means that that instrument becomes available for
 * synthesizing notes. The instrument is loaded into the bank and program
 * location specified by its {@code Patch} object. Loading does not necessarily
 * mean that subsequently played notes will immediately have the sound of this
 * newly loaded instrument. For the instrument to play notes, one of the
 * synthesizer's {@code MidiChannel} objects must receive (or have received) a
 * program-change message that causes that particular instrument's bank and
 * program number to be selected.
 *
 * @author Kara Kytle
 * @see MidiSystem#getSynthesizer
 * @see Soundbank
 * @see Instrument
 * @see MidiChannel#programChange(int, int)
 * @see Receiver
 * @see Transmitter
 * @see MidiDevice
 */
public interface Synthesizer extends MidiDevice {

    // SYNTHESIZER METHODS

    
Obtains the maximum number of notes that this synthesizer can sound
simultaneously.

See Also:
Returns:the maximum number of simultaneous notes
/**
     * Obtains the maximum number of notes that this synthesizer can sound
     * simultaneously.
     *
     * @return the maximum number of simultaneous notes
     * @see #getVoiceStatus
     */
    int getMaxPolyphony();

    
Obtains the processing latency incurred by this synthesizer, expressed in
microseconds. This latency measures the worst-case delay between the time
a MIDI message is delivered to the synthesizer and the time that the
synthesizer actually produces the corresponding result.


Although the latency is expressed in microseconds, a synthesizer's actual
measured delay may vary over a wider range than this resolution suggests.
For example, a synthesizer might have a worst-case delay of a few
milliseconds or more.

Returns:the worst-case delay, in microseconds
/**
     * Obtains the processing latency incurred by this synthesizer, expressed in
     * microseconds. This latency measures the worst-case delay between the time
     * a MIDI message is delivered to the synthesizer and the time that the
     * synthesizer actually produces the corresponding result.
     * <p>
     * Although the latency is expressed in microseconds, a synthesizer's actual
     * measured delay may vary over a wider range than this resolution suggests.
     * For example, a synthesizer might have a worst-case delay of a few
     * milliseconds or more.
     *
     * @return the worst-case delay, in microseconds
     */
    long getLatency();

    
Obtains the set of MIDI channels controlled by this synthesizer. Each non-null element in the returned array is a MidiChannel that receives the MIDI messages sent on that channel number. 
 The MIDI 1.0 specification provides for 16 channels, so this method returns an array of at least 16 elements. However, if this synthesizer doesn't make use of all 16 channels, some of the elements of the array might be null, so you should check each element before using it. 
Returns:an array of the MidiChannel objects managed by this Synthesizer. Some of the array elements may be null.
/**
     * Obtains the set of MIDI channels controlled by this synthesizer. Each
     * non-null element in the returned array is a {@code MidiChannel} that
     * receives the MIDI messages sent on that channel number.
     * <p>
     * The MIDI 1.0 specification provides for 16 channels, so this method
     * returns an array of at least 16 elements. However, if this synthesizer
     * doesn't make use of all 16 channels, some of the elements of the array
     * might be {@code null}, so you should check each element before using it.
     *
     * @return an array of the {@code MidiChannel} objects managed by this
     *         {@code Synthesizer}. Some of the array elements may be
     *         {@code null}.
     */
    MidiChannel[] getChannels();

    
Obtains the current status of the voices produced by this synthesizer. If this class of Synthesizer does not provide voice information, the returned array will always be of length 0. Otherwise, its length is always equal to the total number of voices, as returned by getMaxPolyphony(). (See the VoiceStatus class description for an explanation of synthesizer voices.) 
See Also:
Returns:an array of VoiceStatus objects that supply information about the corresponding synthesizer voices
/**
     * Obtains the current status of the voices produced by this synthesizer. If
     * this class of {@code Synthesizer} does not provide voice information, the
     * returned array will always be of length 0. Otherwise, its length is
     * always equal to the total number of voices, as returned by
     * {@code getMaxPolyphony()}. (See the {@code VoiceStatus} class description
     * for an explanation of synthesizer voices.)
     *
     * @return an array of {@code VoiceStatus} objects that supply information
     *         about the corresponding synthesizer voices
     * @see #getMaxPolyphony
     * @see VoiceStatus
     */
    VoiceStatus[] getVoiceStatus();

    
Informs the caller whether this synthesizer is capable of loading instruments from the specified soundbank. If the soundbank is unsupported, any attempts to load instruments from it will result in an IllegalArgumentException. 
Params:
  • soundbank – soundbank for which support is queried
See Also:
Returns:true if the soundbank is supported, otherwise false
/**
     * Informs the caller whether this synthesizer is capable of loading
     * instruments from the specified soundbank. If the soundbank is
     * unsupported, any attempts to load instruments from it will result in an
     * {@code IllegalArgumentException}.
     *
     * @param  soundbank soundbank for which support is queried
     * @return {@code true} if the soundbank is supported, otherwise
     *         {@code false}
     * @see #loadInstruments
     * @see #loadAllInstruments
     * @see #unloadInstruments
     * @see #unloadAllInstruments
     * @see #getDefaultSoundbank
     */
    boolean isSoundbankSupported(Soundbank soundbank);

    
Makes a particular instrument available for synthesis. This instrument is loaded into the patch location specified by its Patch object, so that if a program-change message is received (or has been received) that causes that patch to be selected, subsequent notes will be played using the sound of instrument. If the specified instrument is already loaded, this method does nothing and returns true. 
 The instrument must be part of a soundbank that this Synthesizer supports. (To make sure, you can use the getSoundbank method of Instrument and the isSoundbankSupported method of Synthesizer.) 
Params:
  • instrument – instrument to load
Throws:
See Also:
Returns:true if the instrument is successfully loaded (or already had been), false if the instrument could not be loaded (for example, if the synthesizer has insufficient memory to load it)
/**
     * Makes a particular instrument available for synthesis. This instrument is
     * loaded into the patch location specified by its {@code Patch} object, so
     * that if a program-change message is received (or has been received) that
     * causes that patch to be selected, subsequent notes will be played using
     * the sound of {@code instrument}. If the specified instrument is already
     * loaded, this method does nothing and returns {@code true}.
     * <p>
     * The instrument must be part of a soundbank that this {@code Synthesizer}
     * supports. (To make sure, you can use the {@code getSoundbank} method of
     * {@code Instrument} and the {@code isSoundbankSupported} method of
     * {@code Synthesizer}.)
     *
     * @param  instrument instrument to load
     * @return {@code true} if the instrument is successfully loaded (or already
     *         had been), {@code false} if the instrument could not be loaded
     *         (for example, if the synthesizer has insufficient memory to load
     *         it)
     * @throws IllegalArgumentException if this {@code Synthesizer} doesn't
     *         support the specified instrument's soundbank
     * @see #unloadInstrument
     * @see #loadInstruments
     * @see #loadAllInstruments
     * @see #remapInstrument
     * @see SoundbankResource#getSoundbank
     * @see MidiChannel#programChange(int, int)
     */
    boolean loadInstrument(Instrument instrument);

    
Unloads a particular instrument.

Params:
  • instrument – instrument to unload
Throws:
See Also:
/**
     * Unloads a particular instrument.
     *
     * @param  instrument instrument to unload
     * @throws IllegalArgumentException if this {@code Synthesizer} doesn't
     *         support the specified instrument's soundbank
     * @see #loadInstrument
     * @see #unloadInstruments
     * @see #unloadAllInstruments
     * @see #getLoadedInstruments
     * @see #remapInstrument
     */
    void unloadInstrument(Instrument instrument);

    
Remaps an instrument. Instrument to takes the place of instrument from. 
 For example, if from was located at bank number 2, program number 11, remapping causes that bank and program location to be occupied instead by to. 
 If the function succeeds, instrument from is unloaded. 
 To cancel the remapping reload instrument from by invoking one of loadInstrument, loadInstruments or loadAllInstruments. 
Params:
  • from – the Instrument object to be replaced
  • to – the Instrument object to be used in place of the old instrument, it should be loaded into the synthesizer
Throws:
See Also:
Returns:true if the instrument successfully remapped, false if feature is not implemented by synthesizer
/**
     * Remaps an instrument. Instrument {@code to} takes the place of instrument
     * {@code from}.
     * <br>
     * For example, if {@code from} was located at bank number 2, program number
     * 11, remapping causes that bank and program location to be occupied
     * instead by {@code to}.
     * <br>
     * If the function succeeds, instrument {@code from} is unloaded.
     * <p>
     * To cancel the remapping reload instrument {@code from} by invoking one of
     * {@link #loadInstrument}, {@link #loadInstruments} or
     * {@link #loadAllInstruments}.
     *
     * @param  from the {@code Instrument} object to be replaced
     * @param  to the {@code Instrument} object to be used in place of the old
     *         instrument, it should be loaded into the synthesizer
     * @return {@code true} if the instrument successfully remapped,
     *         {@code false} if feature is not implemented by synthesizer
     * @throws IllegalArgumentException if instrument {@code from} or instrument
     *         {@code to} aren't supported by synthesizer or if instrument
     *         {@code to} is not loaded
     * @throws NullPointerException if {@code from} or {@code to} parameters
     *         have null value
     * @see #loadInstrument
     * @see #loadInstruments
     * @see #loadAllInstruments
     */
    boolean remapInstrument(Instrument from, Instrument to);

    
Obtains the default soundbank for the synthesizer, if one exists. (Some
synthesizers provide a default or built-in soundbank.) If a synthesizer
doesn't have a default soundbank, instruments must be loaded explicitly
from an external soundbank.

See Also:
Returns:default soundbank, or null if one does not exist
/**
     * Obtains the default soundbank for the synthesizer, if one exists. (Some
     * synthesizers provide a default or built-in soundbank.) If a synthesizer
     * doesn't have a default soundbank, instruments must be loaded explicitly
     * from an external soundbank.
     *
     * @return default soundbank, or {@code null} if one does not exist
     * @see #isSoundbankSupported
     */
    Soundbank getDefaultSoundbank();

    
Obtains a list of instruments that come with the synthesizer. These
instruments might be built into the synthesizer, or they might be part of
a default soundbank provided with the synthesizer, etc.

 Note that you don't use this method to find out which instruments are currently loaded onto the synthesizer; for that purpose, you use getLoadedInstruments(). Nor does the method indicate all the instruments that can be loaded onto the synthesizer; it only indicates the subset that come with the synthesizer. To learn whether another instrument can be loaded, you can invoke isSoundbankSupported(), and if the instrument's Soundbank is supported, you can try loading the instrument. 
See Also:
Returns:list of available instruments. If the synthesizer has no
        instruments coming with it, an array of length 0 is returned.
/**
     * Obtains a list of instruments that come with the synthesizer. These
     * instruments might be built into the synthesizer, or they might be part of
     * a default soundbank provided with the synthesizer, etc.
     * <p>
     * Note that you don't use this method to find out which instruments are
     * currently loaded onto the synthesizer; for that purpose, you use
     * {@code getLoadedInstruments()}. Nor does the method indicate all the
     * instruments that can be loaded onto the synthesizer; it only indicates
     * the subset that come with the synthesizer. To learn whether another
     * instrument can be loaded, you can invoke {@code isSoundbankSupported()},
     * and if the instrument's {@code Soundbank} is supported, you can try
     * loading the instrument.
     *
     * @return list of available instruments. If the synthesizer has no
     *         instruments coming with it, an array of length 0 is returned.
     * @see #getLoadedInstruments
     * @see #isSoundbankSupported(Soundbank)
     * @see #loadInstrument
     */
    Instrument[] getAvailableInstruments();

    
Obtains a list of the instruments that are currently loaded onto this Synthesizer. 
See Also:
Returns:a list of currently loaded instruments
/**
     * Obtains a list of the instruments that are currently loaded onto this
     * {@code Synthesizer}.
     *
     * @return a list of currently loaded instruments
     * @see #loadInstrument
     * @see #getAvailableInstruments
     * @see Soundbank#getInstruments
     */
    Instrument[] getLoadedInstruments();

    
Loads onto the Synthesizer all instruments contained in the specified Soundbank. 
Params:
  • soundbank – the Soundbank whose are instruments are to be loaded
Throws:
See Also:
Returns:true if the instruments are all successfully loaded (or already had been), false if any instrument could not be loaded (for example, if the Synthesizer had insufficient memory)
/**
     * Loads onto the {@code Synthesizer} all instruments contained in the
     * specified {@code Soundbank}.
     *
     * @param  soundbank the {@code Soundbank} whose are instruments are to be
     *         loaded
     * @return {@code true} if the instruments are all successfully loaded (or
     *         already had been), {@code false} if any instrument could not be
     *         loaded (for example, if the {@code Synthesizer} had insufficient
     *         memory)
     * @throws IllegalArgumentException if the requested soundbank is
     *         incompatible with this synthesizer
     * @see #isSoundbankSupported
     * @see #loadInstrument
     * @see #loadInstruments
     */
    boolean loadAllInstruments(Soundbank soundbank);

    
Unloads all instruments contained in the specified Soundbank. 
Params:
  • soundbank – soundbank containing instruments to unload
Throws:
See Also:
/**
     * Unloads all instruments contained in the specified {@code Soundbank}.
     *
     * @param  soundbank soundbank containing instruments to unload
     * @throws IllegalArgumentException thrown if the soundbank is not supported
     * @see #isSoundbankSupported
     * @see #unloadInstrument
     * @see #unloadInstruments
     */
    void unloadAllInstruments(Soundbank soundbank);

    
Loads the instruments referenced by the specified patches, from the specified Soundbank. Each of the Patch objects indicates a bank and program number; the Instrument that has the matching Patch is loaded into that bank and program location. 
Params:
  • soundbank – the Soundbank containing the instruments to load
  • patchList – list of patches for which instruments should be loaded
Throws:
See Also:
Returns:true if the instruments are all successfully loaded (or already had been), false if any instrument could not be loaded (for example, if the Synthesizer had insufficient memory)
/**
     * Loads the instruments referenced by the specified patches, from the
     * specified {@code Soundbank}. Each of the {@code Patch} objects indicates
     * a bank and program number; the {@code Instrument} that has the matching
     * {@code Patch} is loaded into that bank and program location.
     *
     * @param  soundbank the {@code Soundbank} containing the instruments to
     *         load
     * @param  patchList list of patches for which instruments should be loaded
     * @return {@code true} if the instruments are all successfully loaded (or
     *         already had been), {@code false} if any instrument could not be
     *         loaded (for example, if the {@code Synthesizer} had insufficient
     *         memory)
     * @throws IllegalArgumentException thrown if the soundbank is not supported
     * @see #isSoundbankSupported
     * @see Instrument#getPatch
     * @see #loadAllInstruments
     * @see #loadInstrument
     * @see Soundbank#getInstrument(Patch)
     * @see Sequence#getPatchList()
     */
    boolean loadInstruments(Soundbank soundbank, Patch[] patchList);

    
Unloads the instruments referenced by the specified patches, from the
MIDI sound bank specified.

Params:
  • soundbank – soundbank containing instruments to unload
  • patchList – list of patches for which instruments should be
        unloaded
Throws:
See Also:
/**
     * Unloads the instruments referenced by the specified patches, from the
     * MIDI sound bank specified.
     *
     * @param  soundbank soundbank containing instruments to unload
     * @param  patchList list of patches for which instruments should be
     *         unloaded
     * @throws IllegalArgumentException thrown if the soundbank is not supported
     * @see #unloadInstrument
     * @see #unloadAllInstruments
     * @see #isSoundbankSupported
     * @see Instrument#getPatch
     * @see #loadInstruments
     */
    void unloadInstruments(Soundbank soundbank, Patch[] patchList);

    // RECEIVER METHODS

    /**
     * Obtains the name of the receiver.
     *
     * @return receiver name
     */
    //  abstract String getName();

    /**
     * Opens the receiver.
     *
     * @throws MidiUnavailableException if the receiver is cannot be opened,
     *         usually because the MIDI device is in use by another application
     * @throws SecurityException if the receiver cannot be opened due to
     *         security restrictions
     */
    //  abstract void open() throws MidiUnavailableException, SecurityException;

    /**
     * Closes the receiver.
     */
    //  abstract void close();

    /**
     * Sends a MIDI event to the receiver.
     *
     * @param  event event to send
     * @throws IllegalStateException if the receiver is not open
     */
    //  void send(MidiEvent event) throws IllegalStateException {
    //
    //  }

    /**
     * Obtains the set of controls supported by the element. If no controls are
     * supported, returns an array of length 0.
     *
     * @return set of controls
     */
    // $$kk: 03.04.99: josh bloch recommends getting rid of this:
    // what can you really do with a set of untyped controls??
    // $$kk: 03.05.99: i am putting this back in. for one thing,
    // you can check the length and know whether you should keep
    // looking....
    // Control[] getControls();

    /**
     * Obtains the specified control.
     *
     * @param  controlClass class of the requested control
     * @return requested control object, or null if the control is not supported
     */
    // Control getControl(Class controlClass);
}