RecordedInputStream.java

/*
 * GNU LESSER GENERAL PUBLIC LICENSE Copyright (C) 2006 The Lobo Project
 * 
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 2.1 of the License, or (at your option)
 * any later version.
 * 
 * This library 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 Lesser General Public License for more
 * details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 * 
 * Contact info: lobochief@users.sourceforge.net
 */
/*
 * Created on Apr 15, 2005
 */
package com.nvarghese.beowulf.common.cobra.util.io;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * Wraps an InputStream and records all of the bytes read. This stream supports
 * mark() and reset().
 * <p>
 * Note: Buffered streams should wrap this class as opposed to the other way
 * around.
 * 
 * @author J. H. S.
 */
public class RecordedInputStream extends InputStream {

	private final InputStream delegate;
	private final ByteArrayOutputStream store = new ByteArrayOutputStream();
	private final int maxBufferSize;
	private boolean hasReachedEOF = false;
	private boolean hasReachedMaxBufferSize = false;
	private int markPosition = -1;
	private int readPosition = -1;
	private byte[] resetBuffer = null;

	/**
	 * 
	 */
	public RecordedInputStream(final InputStream delegate, final int maxBufferSize) {

		super();
		this.delegate = delegate;
		this.maxBufferSize = maxBufferSize;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.io.InputStream#read()
	 */
	public int read() throws IOException {

		if (this.readPosition != -1 && this.readPosition < this.resetBuffer.length) {
			int b = this.resetBuffer[this.readPosition];
			this.readPosition++;
			return b;
		} else {
			int b = this.delegate.read();
			if (b != -1) {
				if (!this.hasReachedMaxBufferSize) {
					this.store.write(b);
					if (this.store.size() > this.maxBufferSize) {
						this.hasReachedMaxBufferSize = true;
					}
				}
			} else {
				this.hasReachedEOF = true;
			}
			return b;
		}
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.io.InputStream#available()
	 */
	public int available() throws IOException {

		return this.delegate.available();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.io.InputStream#close()
	 */
	public void close() throws IOException {

		this.delegate.close();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.io.InputStream#markSupported()
	 */
	public boolean markSupported() {

		return true;
	}

	public synchronized void mark(final int readlimit) {

		if (this.hasReachedMaxBufferSize) {
			throw new java.lang.IllegalStateException("Maximum buffer size was already reached.");
		}
		this.markPosition = this.store.size();
	}

	public synchronized void reset() throws IOException {

		if (this.hasReachedMaxBufferSize) {
			throw new java.lang.IllegalStateException("Maximum buffer size was already reached.");
		}
		int mp = this.markPosition;
		byte[] wholeBuffer = this.store.toByteArray();
		byte[] resetBuffer = new byte[wholeBuffer.length - mp];
		System.arraycopy(wholeBuffer, mp, resetBuffer, 0, resetBuffer.length);
		this.resetBuffer = resetBuffer;
		this.readPosition = 0;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.io.InputStream#read(byte[], int, int)
	 */
	public int read(final byte[] buffer, final int offset, final int length) throws IOException {

		if (this.readPosition != -1 && this.readPosition < this.resetBuffer.length) {
			int minLength = Math.min(this.resetBuffer.length - this.readPosition, length);
			System.arraycopy(this.resetBuffer, this.readPosition, buffer, offset, minLength);
			this.readPosition += minLength;
			return minLength;
		} else {
			int numRead = this.delegate.read(buffer, offset, length);
			if (numRead != -1) {
				if (!this.hasReachedMaxBufferSize) {
					this.store.write(buffer, offset, numRead);
					if (this.store.size() > this.maxBufferSize) {
						this.hasReachedMaxBufferSize = true;
					}
				}
			} else {
				this.hasReachedEOF = true;
			}
			return numRead;
		}
	}

	public void consumeToEOF() throws IOException {

		byte[] buffer = new byte[8192];
		while (this.read(buffer) != -1) {
			;
		}
	}

	public byte[] getBytesRead() throws BufferExceededException {

		if (this.hasReachedMaxBufferSize) {
			throw new BufferExceededException();
		}
		return this.store.toByteArray();
	}

	public String getString(final String encoding) throws java.io.UnsupportedEncodingException, BufferExceededException {

		if (this.hasReachedMaxBufferSize) {
			throw new BufferExceededException();
		}
		byte[] bytes = this.store.toByteArray();
		return new String(bytes, encoding);
	}

	public boolean hasReachedEOF() {

		return this.hasReachedEOF;
	}
}