Module java.desktop
Package javax.sound.sampled

# Interface Mixer

All Superinterfaces:
  `AutoCloseable`, `Line`

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.

Since:
  1.3

## Nested Class Summary

Nested Classes
Modifier and Type
Interface
Description
`static class`
`Mixer.Info`
The `Mixer.Info` class represents information about an audio mixer, including the product's name, version, and vendor, along with a textual description.

## Method Summary

Modifier and Type
Method
Description
`Line`
`getLine(Line.Info info)`
Obtains a line that is available for use and that matches the description in the specified `Line.Info` object.
`int`
`getMaxLines(Line.Info info)`
Obtains the approximate maximum number of lines of the requested type that can be open simultaneously on the mixer.
`Mixer.Info`
`getMixerInfo()`
Obtains information about this mixer, including the product's name, version, vendor, etc.
`Line.Info[]`
`getSourceLineInfo()`
Obtains information about the set of source lines supported by this mixer.
`Line.Info[]`
`getSourceLineInfo(Line.Info info)`
Obtains information about source lines of a particular type supported by the mixer.
`Line[]`
`getSourceLines()`
Obtains the set of all source lines currently open to this mixer.
`Line.Info[]`
`getTargetLineInfo()`
Obtains information about the set of target lines supported by this mixer.
`Line.Info[]`
`getTargetLineInfo(Line.Info info)`
Obtains information about target lines of a particular type supported by the mixer.
`Line[]`
`getTargetLines()`
Obtains the set of all target lines currently open from this mixer.
`boolean`
`isLineSupported(Line.Info info)`
Indicates whether the mixer supports a line (or lines) that match the specified `Line.Info` object.
`boolean`
`isSynchronizationSupported(Line[] lines, boolean maintainSync)`
Reports whether this mixer supports synchronization of the specified set of lines.
`void`
`synchronize(Line[] lines, boolean maintainSync)`
Synchronizes two or more lines.
`void`
`unsynchronize(Line[] lines)`
Releases synchronization for the specified lines.

### Methods declared in interface javax.sound.sampled.Line

`addLineListener, close, getControl, getControls, getLineInfo, isControlSupported, isOpen, open, removeLineListener`

## Method Details

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

If a `DataLine` is requested, and `info` is an instance of `DataLine.Info` specifying at least one fully qualified audio format, the last one will be used as the default format of the returned `DataLine`.

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