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- /*
- * 11/19/04 1.0 moved to LGPL.
- * 29/01/00 Initial version. mdm@techie.com
- *-----------------------------------------------------------------------
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Library General Public License as published
- * by the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- *----------------------------------------------------------------------
- */
- package javazoom.jl.player;
- import javazoom.jl.decoder.Decoder;
- import javazoom.jl.decoder.JavaLayerException;
- /**
- * The <code>AudioDeviceBase</code> class provides a simple thread-safe
- * implementation of the <code>AudioDevice</code> interface.
- * Template methods are provided for subclasses to override and
- * in doing so provide the implementation for the main operations
- * of the <code>AudioDevice</code> interface.
- *
- * @since 0.0.8
- * @author Mat McGowan
- */
- /*
- * REVIEW: It is desirable to be able to use the decoder whe
- * in the implementation of open(), but the decoder
- * has not yet read a frame, and so much of the
- * desired information (sample rate, channels etc.)
- * are not available.
- */
- public abstract class AudioDeviceBase implements AudioDevice
- {
- private boolean open = false;
-
- private Decoder decoder = null;
-
- /**
- * Opens this audio device.
- *
- * @param decoder The decoder that will provide audio data
- * to this audio device.
- */
- public synchronized void open(Decoder decoder) throws JavaLayerException
- {
- if (!isOpen())
- {
- this.decoder = decoder;
- openImpl();
- setOpen(true);
- }
- }
-
- /**
- * Template method to provide the
- * implementation for the opening of the audio device.
- */
- protected void openImpl() throws JavaLayerException
- {
- }
-
- /**
- * Sets the open state for this audio device.
- */
- protected void setOpen(boolean open)
- {
- this.open = open;
- }
-
- /**
- * Determines if this audio device is open or not.
- *
- * @return <code>true</code> if the audio device is open,
- * <code>false</code> if it is not.
- */
- public synchronized boolean isOpen()
- {
- return open;
- }
-
- /**
- * Closes this audio device. If the device is currently playing
- * audio, playback is stopped immediately without flushing
- * any buffered audio data.
- */
- public synchronized void close()
- {
- if (isOpen())
- {
- closeImpl();
- setOpen(false);
- decoder = null;
- }
- }
-
- /**
- * Template method to provide the implementation for
- * closing the audio device.
- */
- protected void closeImpl()
- {
- }
-
- /**
- * Writes audio data to this audio device. Audio data is
- * assumed to be in the output format of the decoder. This
- * method may return before the data has actually been sounded
- * by the device if the device buffers audio samples.
- *
- * @param samples The samples to write to the audio device.
- * @param offs The offset into the array of the first sample to write.
- * @param len The number of samples from the array to write.
- * @throws JavaLayerException if the audio data could not be
- * written to the audio device.
- * If the audio device is not open, this method does nthing.
- */
- public void write(short[] samples, int offs, int len)
- throws JavaLayerException
- {
- if (isOpen())
- {
- writeImpl(samples, offs, len);
- }
- }
-
- /**
- * Template method to provide the implementation for
- * writing audio samples to the audio device.
- */
- protected void writeImpl(short[] samples, int offs, int len)
- throws JavaLayerException
- {
- }
-
- /**
- * Waits for any buffered audio samples to be played by the
- * audio device. This method should only be called prior
- * to closing the device.
- */
- public void flush()
- {
- if (isOpen())
- {
- flushImpl();
- }
- }
-
- /**
- * Template method to provide the implementation for
- * flushing any buffered audio data.
- */
- protected void flushImpl()
- {
- }
-
- /**
- * Retrieves the decoder that provides audio data to this
- * audio device.
- *
- * @return The associated decoder.
- */
- protected Decoder getDecoder()
- {
- return decoder;
- }
- }
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