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package javax.sound.midi;

/**

 * 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.

     *

     * @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.

     * <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 {@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 {@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

     * {@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 {@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.

     *

     * @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 {@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.

     *

     * @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.

     * <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

     * {@code Synthesizer}.

     *

     * @return a list of currently loaded instruments

     * @see #loadInstrument

     * @see #getAvailableInstruments

     * @see Soundbank#getInstruments

     */

    Instrument[] getLoadedInstruments();

    /**

     * 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 {@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 {@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.

     *

     * @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);

}