GZIPResponseStream.java

/*
 * Copyright 2013 cruxframework.org.
 * 
 * Licensed 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.cruxframework.crux.core.server.http;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.GZIPOutputStream;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;

/**
 * 
 * @author Thiago da Rosa de Bustamante
 *
 */
class GZIPResponseStream extends ServletOutputStream 
{ 
	protected ByteArrayOutputStream baos = null;
	protected GZIPOutputStream gzipstream = null;
	protected boolean closed = false;
	protected HttpServletResponse response = null;
	protected ServletOutputStream output = null;

	public GZIPResponseStream(HttpServletResponse response) throws IOException 
	{
		super();
		closed = false;
		this.response = response;
		this.output = response.getOutputStream();
		baos = new ByteArrayOutputStream();
		gzipstream = new GZIPOutputStream(baos);
	}

	public void close() throws IOException 
	{
		if (closed) 
		{
			throw new IOException("This output stream has already been closed");
		}
		gzipstream.finish();

		byte[] bytes = baos.toByteArray();

		response.addHeader("Content-Length", Integer.toString(bytes.length)); 
		response.addHeader("Content-Encoding", "gzip");
		output.write(bytes);
		output.flush();
		output.close();
		closed = true;
	}

	public void flush() throws IOException 
	{
		if (closed) 
		{
			throw new IOException("Cannot flush a closed output stream");
		}
		gzipstream.flush();
	}

	public void write(int b) throws IOException 
	{
		if (closed) 
		{
			throw new IOException("Cannot write to a closed output stream");
		}
		gzipstream.write((byte)b);
	}

	public void write(byte b[]) throws IOException 
	{
		write(b, 0, b.length);
	}

	public void write(byte b[], int off, int len) throws IOException 
	{
		if (closed) 
		{
			throw new IOException("Cannot write to a closed output stream");
		}
		gzipstream.write(b, off, len);
	}

	public boolean closed() 
	{
		return (this.closed);
	}

	public void reset() 
	{
		//noop
	}
}