AbstractFilterInputStream.java

/**
Copyright (C) 2012  Delcyon, Inc.

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 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 General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package com.delcyon.capo.datastream.stream_attribute_filter;

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;


/**
 * @author jeremiah
 *
 */
public abstract class AbstractFilterInputStream extends FilterInputStream implements StreamAttributeFilter
{

	private final byte[] smallBuffer = new byte[1]; 
	@Override
	public String getName()
	{
		return getClass().getAnnotation(InputStreamAttributeFilterProvider.class).name();
	}
	
	protected AbstractFilterInputStream(InputStream in)
	{
		super(in);		
	}
	
	@Override
	public int read(byte[] b) throws IOException
	{
		return read(b,0,b.length);
	}
	
	@Override
	public int read() throws IOException
	{
		 int bytesRead = read(smallBuffer, 0, 1);
		 if (bytesRead > 0)  //because we are always passing a buffer of length 1, this should never be zero
		 {
		     //the bytes come in as signed, so we need to mask them to unsigned so that code using the int read() method always gets a postive result as expected
			 return (int)(smallBuffer[0] & 0xff);
		 }
		 else //if we're closed, then return -1 to indicate as much
		 {
		     //clear the buffer when we haven't read anything, just in case we use the stream again, like in a zipstream  
		     smallBuffer[0] = (byte)0;
			 return -1;
		 }
	}
}