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package javax.sound.sampled.spi;
import java.util.stream.Stream;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;
import static javax.sound.sampled.AudioFormat.Encoding;
/**
* A format conversion provider provides format conversion services from one or
* more input formats to one or more output formats. Converters include codecs,
* which encode and/or decode audio data, as well as transcoders, etc. Format
* converters provide methods for determining what conversions are supported and
* for obtaining an audio stream from which converted data can be read.
* <p>
* The source format represents the format of the incoming audio data, which
* will be converted.
* <p>
* The target format represents the format of the processed, converted audio
* data. This is the format of the data that can be read from the stream
* returned by one of the {@code getAudioInputStream} methods.
*
* @author Kara Kytle
* @since 1.3
*/
public abstract class FormatConversionProvider {
/**
* Obtains the set of source format encodings from which format conversion
* services are provided by this provider.
*
* @return array of source format encodings. If for some reason provider
* does not provide any conversion services, an array of length 0 is
* returned.
*/
public abstract Encoding[] getSourceEncodings();
/**
* Obtains the set of target format encodings to which format conversion
* services are provided by this provider.
*
* @return array of target format encodings. If for some reason provider
* does not provide any conversion services, an array of length 0 is
* returned.
*/
public abstract Encoding[] getTargetEncodings();
/**
* Indicates whether the format converter supports conversion from the
* specified source format encoding.
*
* @param sourceEncoding the source format encoding for which support is
* queried
* @return {@code true} if the encoding is supported, otherwise
* {@code false}
* @throws NullPointerException if {@code sourceEncoding} is {@code null}
*/
public boolean isSourceEncodingSupported(final Encoding sourceEncoding) {
return Stream.of(getSourceEncodings()).anyMatch(sourceEncoding::equals);
}
/**
* Indicates whether the format converter supports conversion to the
* specified target format encoding.
*
* @param targetEncoding the target format encoding for which support is
* queried
* @return {@code true} if the encoding is supported, otherwise
* {@code false}
* @throws NullPointerException if {@code targetEncoding} is {@code null}
*/
public boolean isTargetEncodingSupported(final Encoding targetEncoding) {
return Stream.of(getTargetEncodings()).anyMatch(targetEncoding::equals);
}
/**
* Obtains the set of target format encodings supported by the format
* converter given a particular source format. If no target format encodings
* are supported for this source format, an array of length 0 is returned.
*
* @param sourceFormat format of the incoming data
* @return array of supported target format encodings
* @throws NullPointerException if {@code sourceFormat} is {@code null}
*/
public abstract Encoding[] getTargetEncodings(AudioFormat sourceFormat);
/**
* Indicates whether the format converter supports conversion to a
* particular encoding from a particular format.
*
* @param targetEncoding desired encoding of the outgoing data
* @param sourceFormat format of the incoming data
* @return {@code true} if the conversion is supported, otherwise
* {@code false}
* @throws NullPointerException if {@code targetEncoding} or
* {@code sourceFormat} are {@code null}
*/
public boolean isConversionSupported(final Encoding targetEncoding,
final AudioFormat sourceFormat) {
return Stream.of(getTargetEncodings(sourceFormat))
.anyMatch(targetEncoding::equals);
}
/**
* Obtains the set of target formats with the encoding specified supported
* by the format converter. If no target formats with the specified encoding
* are supported for this source format, an array of length 0 is returned.
*
* @param targetEncoding desired encoding of the stream after processing
* @param sourceFormat format of the incoming data
* @return array of supported target formats
* @throws NullPointerException if {@code targetEncoding} or
* {@code sourceFormat} are {@code null}
*/
public abstract AudioFormat[] getTargetFormats(Encoding targetEncoding,
AudioFormat sourceFormat);
/**
* Indicates whether the format converter supports conversion to one
* particular format from another.
*
* @param targetFormat desired format of outgoing data
* @param sourceFormat format of the incoming data
* @return {@code true} if the conversion is supported, otherwise
* {@code false}
* @throws NullPointerException if {@code targetFormat} or
* {@code sourceFormat} are {@code null}
*/
public boolean isConversionSupported(final AudioFormat targetFormat,
final AudioFormat sourceFormat) {
final Encoding targetEncoding = targetFormat.getEncoding();
return Stream.of(getTargetFormats(targetEncoding, sourceFormat))
.anyMatch(targetFormat::matches);
}
/**
* Obtains an audio input stream with the specified encoding from the given
* audio input stream.
*
* @param targetEncoding desired encoding of the stream after processing
* @param sourceStream stream from which data to be processed should be
* read
* @return stream from which processed data with the specified target
* encoding may be read
* @throws IllegalArgumentException if the format combination supplied is
* not supported
* @throws NullPointerException if {@code targetEncoding} or
* {@code sourceStream} are {@code null}
*/
public abstract AudioInputStream getAudioInputStream(
Encoding targetEncoding, AudioInputStream sourceStream);
/**
* Obtains an audio input stream with the specified format from the given
* audio input stream.
*
* @param targetFormat desired data format of the stream after processing
* @param sourceStream stream from which data to be processed should be
* read
* @return stream from which processed data with the specified format may be
* read
* @throws IllegalArgumentException if the format combination supplied is
* not supported
* @throws NullPointerException if {@code targetFormat} or
* {@code sourceStream} are {@code null}
*/
public abstract AudioInputStream getAudioInputStream(
AudioFormat targetFormat, AudioInputStream sourceStream);
}