Interface Mixer

public interface Mixer
extends Line

A mixer is an audio device with one or more lines. It need not be designed for mixing audio signals. A mixer that actually mixes audio has multiple input (source) lines and at least one output (target) line. The former are often instances of classes that implement SourceDataLine, and the latter, TargetDataLine. Port objects, too, are either source lines or target lines. A mixer can accept prerecorded, loopable sound as input, by having some of its source lines be instances of objects that implement the Clip interface.

Through methods of the Line interface, which Mixer extends, a mixer might provide a set of controls that are global to the mixer. For example, the mixer can have a master gain control. These global controls are distinct from the controls belonging to each of the mixer's individual lines.

Some mixers, especially those with internal digital mixing capabilities, may provide additional capabilities by implementing the DataLine interface.

A mixer can support synchronization of its lines. When one line in a synchronized group is started or stopped, the other lines in the group automatically start or stop simultaneously with the explicitly affected one.

Methods

getMixerInfo

Mixer.Info getMixerInfo()

Obtains information about this mixer, including the product's name, version, vendor, etc.

Returns:

a mixer info object that describes this mixer

See Also:

Mixer.Info

getSourceLineInfo

Line.Info[] getSourceLineInfo()

Obtains information about the set of source lines supported by this mixer. Some source lines may only be available when this mixer is open.

Returns:

array of Line.Info objects representing source lines for this mixer. If no source lines are supported, an array of length 0 is returned.

getTargetLineInfo

Line.Info[] getTargetLineInfo()

Obtains information about the set of target lines supported by this mixer. Some target lines may only be available when this mixer is open.

Returns:

array of Line.Info objects representing target lines for this mixer. If no target lines are supported, an array of length 0 is returned.

getSourceLineInfo

Line.Info[] getSourceLineInfo(Line.Info info)

Obtains information about source lines of a particular type supported by the mixer. Some source lines may only be available when this mixer is open.

Parameters:

info - a Line.Info object describing lines about which information is queried

Returns:

an array of Line.Info objects describing source lines matching the type requested. If no matching source lines are supported, an array of length 0 is returned.

getTargetLineInfo

Line.Info[] getTargetLineInfo(Line.Info info)

Obtains information about target lines of a particular type supported by the mixer. Some target lines may only be available when this mixer is open.

Parameters:

info - a Line.Info object describing lines about which information is queried

Returns:

an array of Line.Info objects describing target lines matching the type requested. If no matching target lines are supported, an array of length 0 is returned.

isLineSupported

boolean isLineSupported(Line.Info info)

Indicates whether the mixer supports a line (or lines) that match the specified Line.Info object. Some lines may only be supported when this mixer is open.

Parameters:

info - describes the line for which support is queried

Returns:

true if at least one matching line is supported, false otherwise

getLine

Line getLine(Line.Info info)
      throws LineUnavailableException

Parameters:

info - describes the desired line

Returns:

a line that is available for use and that matches the description in the specified Line.Info object

Throws:

LineUnavailableException - if a matching line is not available due to resource restrictions

IllegalArgumentException - if this mixer does not support any lines matching the description

SecurityException - if a matching line is not available due to security restrictions

getMaxLines

int getMaxLines(Line.Info info)

Obtains the approximate maximum number of lines of the requested type that can be open simultaneously on the mixer. Certain types of mixers do not have a hard bound and may allow opening more lines. Since certain lines are a shared resource, a mixer may not be able to open the maximum number of lines if another process has opened lines of this mixer. The requested type is any line that matches the description in the provided Line.Info object. For example, if the info object represents a speaker port, and the mixer supports exactly one speaker port, this method should return 1. If the info object represents a source data line and the mixer supports the use of 32 source data lines simultaneously, the return value should be 32. If there is no limit, this function returns AudioSystem.NOT_SPECIFIED.

Parameters:

info - a Line.Info that describes the line for which the number of supported instances is queried

Returns:

the maximum number of matching lines supported, or AudioSystem.NOT_SPECIFIED

getSourceLines

Line[] getSourceLines()

Obtains the set of all source lines currently open to this mixer.

Returns:

the source lines currently open to the mixer. If no source lines are currently open to this mixer, an array of length 0 is returned.

Throws:

SecurityException - if the matching lines are not available due to security restrictions

getTargetLines

Line[] getTargetLines()

Obtains the set of all target lines currently open from this mixer.

Returns:

target lines currently open from the mixer. If no target lines are currently open from this mixer, an array of length 0 is returned.

Throws:

SecurityException - if the matching lines are not available due to security restrictions

synchronize

void synchronize(Line[] lines,
                 boolean maintainSync)

Synchronizes two or more lines. Any subsequent command that starts or stops audio playback or capture for one of these lines will exert the same effect on the other lines in the group, so that they start or stop playing or capturing data simultaneously.

Parameters:

lines - the lines that should be synchronized

maintainSync - true if the synchronization must be precisely maintained (i.e., the synchronization must be sample-accurate) at all times during operation of the lines , or false if precise synchronization is required only during start and stop operations

Throws:

IllegalArgumentException - if the lines cannot be synchronized. This may occur if the lines are of different types or have different formats for which this mixer does not support synchronization, or if all lines specified do not belong to this mixer.

unsynchronize

void unsynchronize(Line[] lines)

Releases synchronization for the specified lines. The array must be identical to one for which synchronization has already been established; otherwise an exception may be thrown. However, null may be specified, in which case all currently synchronized lines that belong to this mixer are unsynchronized.

Parameters:

lines - the synchronized lines for which synchronization should be released, or null for all this mixer's synchronized lines

Throws:

IllegalArgumentException - if the lines cannot be unsynchronized. This may occur if the argument specified does not exactly match a set of lines for which synchronization has already been established.

isSynchronizationSupported

boolean isSynchronizationSupported(Line[] lines,
                                   boolean maintainSync)

Reports whether this mixer supports synchronization of the specified set of lines.

Parameters:

lines - the set of lines for which synchronization support is queried

maintainSync - true if the synchronization must be precisely maintained (i.e., the synchronization must be sample-accurate) at all times during operation of the lines , or false if precise synchronization is required only during start and stop operations

Returns:

true if the lines can be synchronized, false otherwise