compressionservletresponsewrapper.java

struts_spring_hibernate开发实例

/*
 * CompressionServletResponseWrapper.java
 * $Header: /home/cvs/jakarta-tomcat-4.0/webapps/examples/WEB-INF/classes/compressionFilters/CompressionServletResponseWrapper.java,v 1.9 2002/09/16 19:55:27 amyroh Exp $
 * $Revision: 1.9 $
 * $Date: 2002/09/16 19:55:27 $
 *
 * ====================================================================
 *
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * [Additional notices, if required by prior licensing conditions]
 *
 */
package jaoso.framework.web.filter.compression;

import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;

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

/**
 * Implementation of <b>HttpServletResponseWrapper </b> that works with the
 * CompressionServletResponseStream implementation..
 * 
 * @author Amy Roh
 * @author Dmitri Valdin
 * @version $Revision: 1.9 $, $Date: 2002/09/16 19:55:27 $
 */
public class CompressionServletResponseWrapper extends
		HttpServletResponseWrapper {
	/**
	 * Descriptive information about this Response implementation.
	 */
	protected static final String info = "CompressionServletResponseWrapper";

	// ----------------------------------------------------- Instance Variables

	/**
	 * Original response
	 */
	protected HttpServletResponse origResponse = null;

	/**
	 * The PrintWriter that has been returned by <code>getWriter()</code>, if
	 * any.
	 */
	protected PrintWriter writer = null;

	/**
	 * The ServletOutputStream that has been returned by
	 * <code>getOutputStream()</code>, if any.
	 */
	protected ServletOutputStream stream = null;

	/**
	 * Content type
	 */
	protected String contentType = null;

	/**
	 * The threshold number to compress
	 */
	protected int threshold = 0;

	/**
	 * Debug level
	 */
	private int debug = 0;

	// ----------------------------------------------------- Constructor

	/**
	 * Calls the parent constructor which creates a ServletResponse adaptor
	 * wrapping the given response object.
	 */
	public CompressionServletResponseWrapper(HttpServletResponse response) {
		super(response);
		origResponse = response;

		if (debug > 1) {
			System.out
					.println("CompressionServletResponseWrapper constructor gets called");
		}
	}

	/**
	 * Set threshold number
	 */
	public void setCompressionThreshold(int threshold) {
		if (debug > 1) {
			System.out.println("setCompressionThreshold to " + threshold);
		}

		this.threshold = threshold;
	}

	/**
	 * DOCUMENT ME!
	 * 
	 * @param length
	 *            DOCUMENT ME!
	 */
	public void setContentLength(int length) {
	}

	// --------------------------------------------------------- Public Methods

	/**
	 * Set content type
	 */
	public void setContentType(String contentType) {
		if (debug > 1) {
			System.out.println("setContentType to " + contentType);
		}

		this.contentType = contentType;
		origResponse.setContentType(contentType);
	}

	/**
	 * Set debug level
	 */
	public void setDebugLevel(int debug) {
		this.debug = debug;
	}

	/**
	 * Return the servlet output stream associated with this Response.
	 * 
	 * @exception IllegalStateException
	 *                if <code>getWriter</code> has already been called for
	 *                this response
	 * @exception IOException
	 *                if an input/output error occurs
	 */
	public ServletOutputStream getOutputStream() throws IOException {
		if (writer != null) {
			throw new IllegalStateException(
					"getWriter() has already been called for this response");
		}

		if (stream == null) {
			stream = createOutputStream();
		}

		if (debug > 1) {
			System.out.println("stream is set to " + stream
					+ " in getOutputStream");
		}

		return (stream);
	}

	/**
	 * Return the writer associated with this Response.
	 * 
	 * @exception IllegalStateException
	 *                if <code>getOutputStream</code> has already been called
	 *                for this response
	 * @exception IOException
	 *                if an input/output error occurs
	 */
	public PrintWriter getWriter() throws IOException {
		if (writer != null) {
			return (writer);
		}

		if (stream != null) {
			throw new IllegalStateException(
					"getOutputStream() has already been called for this response");
		}

		stream = createOutputStream();

		if (debug > 1) {
			System.out.println("stream is set to " + stream + " in getWriter");
		}

		//String charset = getCharsetFromContentType(contentType);
		String charEnc = origResponse.getCharacterEncoding();

		if (debug > 1) {
			System.out.println("character encoding is " + charEnc);
		}

		// HttpServletResponse.getCharacterEncoding() shouldn't return null
		// according the spec, so feel free to remove that "if"
		if (charEnc != null) {
			writer = new PrintWriter(new OutputStreamWriter(stream, charEnc));
		} else {
			writer = new PrintWriter(stream);
		}

		return (writer);
	}

	/**
	 * Create and return a ServletOutputStream to write the content associated
	 * with this Response.
	 * 
	 * @exception IOException
	 *                if an input/output error occurs
	 */
	public ServletOutputStream createOutputStream() throws IOException {
		if (debug > 1) {
			System.out.println("createOutputStream gets called");
		}

		CompressionResponseStream stream = new CompressionResponseStream(
				origResponse);
		stream.setDebugLevel(debug);
		stream.setBuffer(threshold);

		return stream;
	}

	/**
	 * Finish a response.
	 */
	public void finishResponse() {
		try {
			if (writer != null) {
				writer.close();
			} else {
				if (stream != null) {
					stream.close();
				}
			}
		} catch (IOException e) {
		}
	}

	// ------------------------------------------------ ServletResponse Methods

	/**
	 * Flush the buffer and commit this response.
	 * 
	 * @exception IOException
	 *                if an input/output error occurs
	 */
	public void flushBuffer() throws IOException {
		if (debug > 1) {
			System.out
					.println("flush buffer @ CompressionServletResponseWrapper");
		}

		((CompressionResponseStream) stream).flush();
	}

	/**
	 * Returns character from content type. This method was taken from tomcat.
	 * 
	 * @author rajo
	 */
	private static String getCharsetFromContentType(String type) {
		if (type == null) {
			return null;
		}

		int semi = type.indexOf(";");

		if (semi == -1) {
			return null;
		}

		String afterSemi = type.substring(semi + 1);
		int charsetLocation = afterSemi.indexOf("charset=");

		if (charsetLocation == -1) {
			return null;
		} else {
			String afterCharset = afterSemi.substring(charsetLocation + 8);
			String encoding = afterCharset.trim();

			return encoding;
		}
	}
}