outputchannels.java

一个详细的javaLayer的源码

/*
 * 12/12/99 Initial implementation.		[e-mail]. 
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 *  (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 General Public License for more details.
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 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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 */

package javazoom.jl.decoder;


/**
 * A Type-safe representation of the the supported output channel
 * constants. 
 * 
 * This class is immutable and, hence, is thread safe. 
 * 
 * @author	Mat McGowan 12/12/99 
 * @since	0.0.7
 */
public class OutputChannels
{		
	/**
	 * Flag to indicate output should include both channels. 
	 */
	public static final int	BOTH_CHANNELS = 0;
		
	/**
	 * Flag to indicate output should include the left channel only. 
	 */
	public static final int	LEFT_CHANNEL = 1;

	/**
	 * Flag to indicate output should include the right channel only. 
	 */
	public static final int	RIGHT_CHANNEL = 2;
		
	/**
	 * Flag to indicate output is mono. 
	 */
	public static final int	DOWNMIX_CHANNELS = 3;

	
	public static final OutputChannels LEFT = new OutputChannels(LEFT_CHANNEL);
	public static final OutputChannels RIGHT = new OutputChannels(RIGHT_CHANNEL);
	public static final OutputChannels BOTH = new OutputChannels(BOTH_CHANNELS);
	public static final OutputChannels DOWNMIX = new OutputChannels(DOWNMIX_CHANNELS);
				
	
	private final int	outputChannels;
			
	/**
	 * Creates an <code>OutputChannels</code> instance
	 * corresponding to the given channel code.
	 * 
	 * @param	code one of the OutputChannels channel code constants.
	 * 
	 * @throws	IllegalArgumentException if code is not a valid
	 *			channel code. 
	 */
	static public OutputChannels fromInt(int code)
	{
		switch (code)
		{
		case LEFT_CHANNEL:
			return LEFT;
		case RIGHT_CHANNEL:
			return RIGHT;
		case BOTH_CHANNELS:
			return BOTH;
		case DOWNMIX_CHANNELS:
			return DOWNMIX;
		default:
			throw new IllegalArgumentException("Invalid channel code: "+code);
		}
	}
		
	private OutputChannels(int channels)
	{
		outputChannels = channels;
			
		if (channels<0 || channels>3)
			throw new IllegalArgumentException("channels");
	}
		
	/**
	 * Retrieves the code representing the desired output channels.
	 * Will be one of LEFT_CHANNEL, RIGHT_CHANNEL, BOTH_CHANNELS
	 * or DOWNMIX_CHANNELS.
	 * 
	 * @return the channel code represented by this instance.
	 */
	public int getChannelsOutputCode()
	{
		return outputChannels;	
	}
		
	/**
	 * Retrieves the number of output channels represented 
	 * by this channel output type.
	 * 
	 * @return	The number of output channels for this channel output
	 *			type. This will be 2 for BOTH_CHANNELS only, and 1
	 *			for all other types. 
	 */
	public int getChannelCount()
	{
		int count = (outputChannels==BOTH_CHANNELS) ?  2 : 1;
		return count;
	}
		
		
	public boolean equals(Object o)
	{
		boolean equals = false;
			
		if (o instanceof OutputChannels)
		{
			OutputChannels oc = (OutputChannels)o;
			equals = (oc.outputChannels == outputChannels);
		}
			
		return equals;
	}
							  
	public int hashCode()
	{
		return outputChannels;	
	}
		
}