- All Superinterfaces:
AutoCloseable
- All Known Subinterfaces:
Sequencer,Synthesizer
MidiDevice is the base interface for all MIDI devices. Common devices
include synthesizers, sequencers, MIDI input ports, and MIDI output ports.
A MidiDevice can be a transmitter or a receiver of MIDI events, or
both. Therefore, it can provide Transmitter or Receiver
instances (or both). Typically, MIDI IN ports provide transmitters, MIDI OUT
ports and synthesizers provide receivers. A Sequencer typically provides
transmitters for playback and receivers for recording.
A MidiDevice can be opened and closed explicitly as well as
implicitly. Explicit opening is accomplished by calling open(),
explicit closing is done by calling close() on the MidiDevice
instance. If an application opens a MidiDevice explicitly, it has to
close it explicitly to free system resources and enable the application to
exit cleanly. Implicit opening is done by calling
MidiSystem.getReceiver() and MidiSystem.getTransmitter(). The
MidiDevice used by MidiSystem.getReceiver and
MidiSystem.getTransmitter is implementation-dependent unless the
properties javax.sound.midi.Receiver and
javax.sound.midi.Transmitter are used (see the description of
properties to select default providers in MidiSystem). A
MidiDevice that was opened implicitly, is closed implicitly by
closing the Receiver or Transmitter that resulted in opening
it. If more than one implicitly opening Receiver or
Transmitter were obtained by the application, the device is closed
after the last Receiver or Transmitter has been closed. On
the other hand, calling getReceiver or getTransmitter on the
device instance directly does not open the device implicitly. Closing these
Transmitters and Receivers does not close the device
implicitly. To use a device with Receivers or Transmitters
obtained this way, the device has to be opened and closed explicitly.
If implicit and explicit opening and closing are mixed on the same
MidiDevice instance, the following rules apply:
- After an explicit open (either before or after implicit opens), the device will not be closed by implicit closing. The only way to close an explicitly opened device is an explicit close.
- An explicit close always closes the device, even if it also has been opened implicitly. A subsequent implicit close has no further effect.
MidiDevice device = ...;
if (!(device instanceof Sequencer) && !(device instanceof Synthesizer)) {
// we're now sure that device represents a MIDI port
// ...
}
A MidiDevice includes a MidiDevice.Info object to provide manufacturer
information and so on.
- See Also:
-
Nested Class Summary
Nested ClassesModifier and TypeInterfaceDescriptionstatic classAMidiDevice.Infoobject contains assorted data about aMidiDevice, including its name, the company who created it, and descriptive text. -
Method Summary
Modifier and TypeMethodDescriptionvoidclose()Closes the device, indicating that the device should now release any system resources it is using.Obtains information about the device, including its Java class andStringscontaining its name, vendor, and description.intObtains the maximum number of MIDI IN connections available on this MIDI device for receiving MIDI data.intObtains the maximum number of MIDI OUT connections available on this MIDI device for transmitting MIDI data.longObtains the current time-stamp of the device, in microseconds.Obtains a MIDI IN receiver through which the MIDI device may receive MIDI data.Returns all currently active, non-closed receivers connected with thisMidiDevice.Obtains a MIDI OUT connection from which the MIDI device will transmit MIDI data.Returns all currently active, non-closed transmitters connected with thisMidiDevice.booleanisOpen()Reports whether the device is open.voidopen()Opens the device, indicating that it should now acquire any system resources it requires and become operational.
-
Method Details
-
getDeviceInfo
MidiDevice.Info getDeviceInfo()Obtains information about the device, including its Java class andStringscontaining its name, vendor, and description.- Returns:
- device info
-
open
Opens the device, indicating that it should now acquire any system resources it requires and become operational.An application opening a device explicitly with this call has to close the device by calling
close(). This is necessary to release system resources and allow applications to exit cleanly.Note that some devices, once closed, cannot be reopened. Attempts to reopen such a device will always result in a
MidiUnavailableException.- Throws:
MidiUnavailableException- thrown if the device cannot be opened due to resource restrictionsSecurityException- thrown if the device cannot be opened due to security restrictions- See Also:
-
close
void close()Closes the device, indicating that the device should now release any system resources it is using.All
ReceiverandTransmitterinstances open from this device are closed. This includes instances retrieved viaMidiSystem.- Specified by:
closein interfaceAutoCloseable- See Also:
-
isOpen
boolean isOpen()Reports whether the device is open. -
getMicrosecondPosition
long getMicrosecondPosition()Obtains the current time-stamp of the device, in microseconds. If a device supports time-stamps, it should start counting at 0 when the device is opened and continue incrementing its time-stamp in microseconds until the device is closed. If it does not support time-stamps, it should always return -1.- Returns:
- the current time-stamp of the device in microseconds, or -1 if time-stamping is not supported by the device
-
getMaxReceivers
int getMaxReceivers()Obtains the maximum number of MIDI IN connections available on this MIDI device for receiving MIDI data.- Returns:
- maximum number of MIDI IN connections, or -1 if an unlimited number of connections is available
-
getMaxTransmitters
int getMaxTransmitters()Obtains the maximum number of MIDI OUT connections available on this MIDI device for transmitting MIDI data.- Returns:
- maximum number of MIDI OUT connections, or -1 if an unlimited number of connections is available
-
getReceiver
Obtains a MIDI IN receiver through which the MIDI device may receive MIDI data. The returned receiver must be closed when the application has finished using it.Usually the returned receiver implements the
MidiDeviceReceiverinterface.Obtaining a
Receiverwith this method does not open the device. To be able to use the device, it has to be opened explicitly by callingopen(). Also, closing theReceiverdoes not close the device. It has to be closed explicitly by callingclose().- Returns:
- a receiver for the device
- Throws:
MidiUnavailableException- thrown if a receiver is not available due to resource restrictions- See Also:
-
getReceivers
Returns all currently active, non-closed receivers connected with thisMidiDevice. A receiver can be removed from the device by closing it.Usually the returned receivers implement the
MidiDeviceReceiverinterface.- Returns:
- an unmodifiable list of the open receivers
- Since:
- 1.5
-
getTransmitter
Obtains a MIDI OUT connection from which the MIDI device will transmit MIDI data. The returned transmitter must be closed when the application has finished using it.Usually the returned transmitter implements the
MidiDeviceTransmitterinterface.Obtaining a
Transmitterwith this method does not open the device. To be able to use the device, it has to be opened explicitly by callingopen(). Also, closing theTransmitterdoes not close the device. It has to be closed explicitly by callingclose().- Returns:
- a MIDI OUT transmitter for the device
- Throws:
MidiUnavailableException- thrown if a transmitter is not available due to resource restrictions- See Also:
-
getTransmitters
List<Transmitter> getTransmitters()Returns all currently active, non-closed transmitters connected with thisMidiDevice. A transmitter can be removed from the device by closing it.Usually the returned transmitters implement the
MidiDeviceTransmitterinterface.- Returns:
- an unmodifiable list of the open transmitters
- Since:
- 1.5
-