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| */ | |
| package javax.sound.sampled; | |
| /** | |
| * A target data line is a type of {@link DataLine} from which audio data can be | |
| * read. The most common example is a data line that gets its data from an audio | |
| * capture device. (The device is implemented as a mixer that writes to the | |
| * target data line.) | |
| * <p> | |
| * Note that the naming convention for this interface reflects the relationship | |
| * between the line and its mixer. From the perspective of an application, a | |
| * target data line may act as a source for audio data. | |
| * <p> | |
| * The target data line can be obtained from a mixer by invoking the | |
| * {@link Mixer#getLine getLine} method of {@code Mixer} with an appropriate | |
| * {@link DataLine.Info} object. | |
| * <p> | |
| * The {@code TargetDataLine} interface provides a method for reading the | |
| * captured data from the target data line's buffer. Applications that record | |
| * audio should read data from the target data line quickly enough to keep the | |
| * buffer from overflowing, which could cause discontinuities in the captured | |
| * data that are perceived as clicks. Applications can use the | |
| * {@link DataLine#available available} method defined in the {@code DataLine} | |
| * interface to determine the amount of data currently queued in the data line's | |
| * buffer. If the buffer does overflow, the oldest queued data is discarded and | |
| * replaced by new data. | |
| * | |
| * @author Kara Kytle | |
| * @see Mixer | |
| * @see DataLine | |
| * @see SourceDataLine | |
| * @since 1.3 | |
| */ | |
| public interface TargetDataLine extends DataLine { | |
| /** | |
| * Opens the line with the specified format and requested buffer size, | |
| * causing the line to acquire any required system resources and become | |
| * operational. | |
| * <p> | |
| * The buffer size is specified in bytes, but must represent an integral | |
| * number of sample frames. Invoking this method with a requested buffer | |
| * size that does not meet this requirement may result in an | |
| * {@code IllegalArgumentException}. The actual buffer size for the open | |
| * line may differ from the requested buffer size. The value actually set | |
| * may be queried by subsequently calling {@link DataLine#getBufferSize} | |
| * <p> | |
| * If this operation succeeds, the line is marked as open, and an | |
| * {@link LineEvent.Type#OPEN OPEN} event is dispatched to the line's | |
| * listeners. | |
| * <p> | |
| * Invoking this method on a line that is already open is illegal and may | |
| * result in an {@code IllegalStateException}. | |
| * <p> | |
| * Some lines, once closed, cannot be reopened. Attempts to reopen such a | |
| * line will always result in a {@code LineUnavailableException}. | |
| * | |
| * @param format the desired audio format | |
| * @param bufferSize the desired buffer size, in bytes | |
| * @throws LineUnavailableException if the line cannot be opened due to | |
| * resource restrictions | |
| * @throws IllegalArgumentException if the buffer size does not represent an | |
| * integral number of sample frames, or if {@code format} is not | |
| * fully specified or invalid | |
| * @throws IllegalStateException if the line is already open | |
| * @see #open(AudioFormat) | |
| * @see Line#open | |
| * @see Line#close | |
| * @see Line#isOpen | |
| * @see LineEvent | |
| */ | |
| void open(AudioFormat format, int bufferSize) throws LineUnavailableException; | |
| /** | |
| * Opens the line with the specified format, causing the line to acquire any | |
| * required system resources and become operational. | |
| * <p> | |
| * The implementation chooses a buffer size, which is measured in bytes but | |
| * which encompasses an integral number of sample frames. The buffer size | |
| * that the system has chosen may be queried by subsequently calling | |
| * {@link DataLine#getBufferSize} | |
| * <p> | |
| * If this operation succeeds, the line is marked as open, and an | |
| * {@link LineEvent.Type#OPEN OPEN} event is dispatched to the line's | |
| * listeners. | |
| * <p> | |
| * Invoking this method on a line that is already open is illegal and may | |
| * result in an {@code IllegalStateException}. | |
| * <p> | |
| * Some lines, once closed, cannot be reopened. Attempts to reopen such a | |
| * line will always result in a {@code LineUnavailableException}. | |
| * | |
| * @param format the desired audio format | |
| * @throws LineUnavailableException if the line cannot be opened due to | |
| * resource restrictions | |
| * @throws IllegalArgumentException if {@code format} is not fully specified | |
| * or invalid | |
| * @throws IllegalStateException if the line is already open | |
| * @see #open(AudioFormat, int) | |
| * @see Line#open | |
| * @see Line#close | |
| * @see Line#isOpen | |
| * @see LineEvent | |
| */ | |
| void open(AudioFormat format) throws LineUnavailableException; | |
| /** | |
| * Reads audio data from the data line's input buffer. The requested number | |
| * of bytes is read into the specified array, starting at the specified | |
| * offset into the array in bytes. This method blocks until the requested | |
| * amount of data has been read. However, if the data line is closed, | |
| * stopped, drained, or flushed before the requested amount has been read, | |
| * the method no longer blocks, but returns the number of bytes read thus | |
| * far. | |
| * <p> | |
| * The number of bytes that can be read without blocking can be ascertained | |
| * using the {@link DataLine#available available} method of the | |
| * {@code DataLine} interface. (While it is guaranteed that this number of | |
| * bytes can be read without blocking, there is no guarantee that attempts | |
| * to read additional data will block.) | |
| * <p> | |
| * The number of bytes to be read must represent an integral number of | |
| * sample frames, such that: | |
| * <p style="text-align:center"> | |
| * {@code [ bytes read ] % [frame size in bytes ] == 0} | |
| * <p> | |
| * The return value will always meet this requirement. A request to read a | |
| * number of bytes representing a non-integral number of sample frames | |
| * cannot be fulfilled and may result in an IllegalArgumentException. | |
| * | |
| * @param b a byte array that will contain the requested input data when | |
| * this method returns | |
| * @param off the offset from the beginning of the array, in bytes | |
| * @param len the requested number of bytes to read | |
| * @return the number of bytes actually read | |
| * @throws IllegalArgumentException if the requested number of bytes does | |
| * not represent an integral number of sample frames, or if | |
| * {@code len} is negative | |
| * @throws ArrayIndexOutOfBoundsException if {@code off} is negative, or | |
| * {@code off+len} is greater than the length of the array {@code b} | |
| * | |
| * @see SourceDataLine#write | |
| * @see DataLine#available | |
| */ | |
| int read(byte[] b, int off, int len); | |
| /** | |
| * Obtains the number of sample frames of audio data that can be read from | |
| * the target data line without blocking. Note that the return value | |
| * measures sample frames, not bytes. | |
| * | |
| * @return the number of sample frames currently available for reading | |
| * @see SourceDataLine#availableWrite | |
| */ | |
| //public int availableRead(); | |
| } |