/* $Id$ */
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.manifoldcf.connectorcommon.fuzzyml;
import org.apache.manifoldcf.core.interfaces.*;
import java.io.*;
/** This class represents an input stream wraps another, and that can be reset and
* played over. It accomplishes this by buffering all bytes that go past, and
* then plays back from that buffer after the reset.
* The caller, at some point, is expected to signal that no further restarts will
* occur, which ends all attempts at buffering.
*/
public class ReplayableInputStream extends InputStream
{
protected final ByteBuffer bytes = new ByteBuffer();
protected final InputStream wrappedStream;
protected int bytePosition = 0;
protected boolean doBuffering = true;
/** Constructor */
public ReplayableInputStream(InputStream wrappedStream)
{
this.wrappedStream = wrappedStream;
}
public void restart(boolean lastRestart)
{
if (doBuffering == false)
throw new IllegalStateException("Can't restart a stream after it has been restarted the last time");
doBuffering = !lastRestart;
bytePosition = 0;
}
@Override
public int read()
throws IOException
{
if (bytePosition < bytes.size())
return 0xff & (int)bytes.readByte(bytePosition++);
int theByte = wrappedStream.read();
if (theByte == -1)
return theByte;
if (doBuffering)
{
bytes.appendByte((byte)theByte);
bytePosition++;
}
return theByte;
}
@Override
public int read(byte[] b, int off, int len)
throws IOException
{
// Use the superclass method that goes through read, if we're within the
// buffer, or we're supposed to be buffering.
if (bytePosition < bytes.size() || doBuffering)
return super.read(b,off,len);
// Outside of the local buffer, vector right through to the remainder stream.
return wrappedStream.read(b,off,len);
}
@Override
public long skip(long n)
throws IOException
{
if (bytePosition < bytes.size())
{
// I hope this reads n bytes, one at a time; that's what the javadoc seems
// to indicate.
return super.skip(n);
}
return wrappedStream.skip(n);
}
@Override
public void close()
throws IOException
{
// Since the wrapped input stream will be closed by someone else,
// we NEVER close it through the wrapper.
}
}