cmsflexresponse.java

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/*
* File   : $Source: /usr/local/cvs/opencms/src/com/opencms/flex/cache/Attic/CmsFlexResponse.java,v $
* Date   : $Date: 2002/05/10 21:07:31 $
* Version: $Revision: 1.1.2.1.2.1 $
*
* This library is part of OpenCms -
* the Open Source Content Mananagement System
*
* Copyright (C) 2002  The OpenCms Group
*
* 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.
*
* For further information about OpenCms, please see the
* OpenCms Website: http://www.opencms.org
*
* 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/


package com.opencms.flex.cache;

import java.util.Map;
import java.util.ArrayList;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * A wrapper class for a HttpServletRequest that controls the Flex cache.
 *
 * @author  Alexander Kandzior ([e-mail])
 * @version $Revision: 1.1.2.1.2.1 $
 */
public class CmsFlexResponse extends javax.servlet.http.HttpServletResponseWrapper {
    
    /** The wrapped ServletResponse */
    private HttpServletResponse m_res = null;    
    
    /** The cached entry that is constructed from this response */
    private CmsFlexCacheEntry m_cachedEntry = null;
    
    /** A special wrapper class for a ServletOutputStream */
    private com.opencms.flex.cache.CmsFlexResponse.CmsServletOutputStream m_out;
    
    /** A printwriter that writes in the m_out stream */
    private java.io.PrintWriter m_writer = null;
    
    /** Indicates that the OutputStream m_out should write ONLY in the buffer */
    private boolean m_writeOnlyToBuffer;
    
    /** Indicates that parent stream is writing only in the buffer */
    private boolean m_parentWritesOnlyToBuffer;
    
    /** A list of include calls that origin from this page, i.e. these are sub elements of this element */
    private java.util.List m_includeList = null;
    
    /** A list of results from the inclusions, needed because of JSP buffering */
    private java.util.List m_includeResults = null;
    
    /** Byte array used for "cached leafs" optimization */
    private byte[] m_cacheBytes = null;
    
    /** The CmsFlexCacheKey for this response */
    private CmsFlexCacheKey m_key = null;

    /** Map to save all response headers (including sub-elements) in */
    private Map m_headers;
    
    /** Map to save response headers belonging to a single include call in */
    private Map m_buffer_headers;

    /** Indicates if this response is suspended (probably because of a redirect) */
    private boolean m_suspended = false;

    /** String to hold a buffered redirect target */
    private String m_buffer_redirect = null;        

    /** Indicates if caching is required, will always be true if m_writeOnlyToBuffer is true */
    private boolean m_cachingRequired = false;       
    
    /** Indicates if this element is currently in include mode, i.e. processing a sub-element */
    private boolean m_includeMode = false;
    
    /** Static string to indicate a header is "set" in the header maps */
    public static final String C_SETHEADER = "[setHeader]";
                
    /** Flag for debugging output */
    private static boolean DEBUG = false;
    
    /** 
     * Constructor for the CmsFlexResponse.
     * This one is usually used for the "Top" response.     
     *
     * @param res The HttpServletResponse to wrap
     * @param streaming Indicates if streaming should be enabled or not
     */
    public CmsFlexResponse(HttpServletResponse res, boolean streaming) {
        super(res);
        m_res = res;
        m_out = null;
        m_parentWritesOnlyToBuffer = ! streaming;
        setOnlyBuffering(m_parentWritesOnlyToBuffer);
        m_headers = new java.util.HashMap(37);
        m_buffer_headers = new java.util.HashMap(17);        
    }
    
    /**
     * Constructor for the CmsFlexResponse.
     * This one is usually used to wrap responses for further include calls in OpenCms.
     *
     * @param res The CmsFlexResponse to wrap     
     */
    public CmsFlexResponse(CmsFlexResponse res) {
        super(res);
        m_res = res;
        m_out = null;
        m_parentWritesOnlyToBuffer = res.hasIncludeList();
        setOnlyBuffering(m_parentWritesOnlyToBuffer);
        m_headers = new java.util.HashMap(37);
        m_buffer_headers = new java.util.HashMap(17);
    }    

    /** 
     * Returns the top wrapped response, i.e. the first response wrapped
     * that is not of type CmsFlexResponse.
     *
     * @return The top wrapped response.
     */
    private HttpServletResponse getTopResponse() {
        if (m_res instanceof CmsFlexResponse) {
            return ((CmsFlexResponse)m_res).getTopResponse();
        } else {
            return m_res;
        }
    }    
    
    /** 
     * Sets buffering status of the response.
     * This must be done before the first output is written.
     * Buffering is needed to process elements that can not be written
     * directly to the output stream because their sub - elements have to
     * be processed seperatly. Which is so far true only for JSP pages.<p>
     *
     * If buffering is on, nothing is written to the output stream
     * even if streaming for this resonse is enabled.
     *
     * @param value The value to set
     */
    public void setOnlyBuffering(boolean value) {
        m_writeOnlyToBuffer = value;
        
        if (m_writeOnlyToBuffer) {
            setCmsCachingRequired(true);
        }      
    }

    /**
     * Set caching status for this reponse.
     * Will always be set to "true" if setOnlyBuffering() is set to "true".
     * Currently this is an optimization for non - JSP elements that 
     * are known not to be cachable.
     *
     * @param value The value to set     
     */
    void setCmsCachingRequired(boolean value) {  
        m_cachingRequired = value || m_writeOnlyToBuffer;
    }    

    /**
     * This flag indicates to the response if it is in "include mode" or not.
     * This is important in case a cache entry is constructed, 
     * since the cache entry must not consist of output or headers of the
     * included elements.
     *
     * @param value The value to set     
     */
    void setCmsIncludeMode(boolean value) {
        m_includeMode = value;
    }
    
    /** 
     * This indicates if the response is suspended or not.
     * A suspended response mut not write further output to any stream or
     * process a cache entry for itself.<p>
     *
     * Currently, a response is only suspended if it is redirected.
     *
     * @return true if the response is suspended, false otherwise
     */
    public boolean isSuspended() {
        return m_suspended;
    }
    
    /**
     * Sets the suspended status of the response, and also sets
     * the suspend status of all responses wrapping this response.
     * A suspended response mut not write further output to any stream or
     * process a cache entry for itself.<p>
     *
     * @param value The value to set     
     */
    void setSuspended(boolean value) {
        m_suspended = value;
        if (m_res instanceof CmsFlexResponse) {
            ((CmsFlexResponse)m_res).setSuspended(value);
        }
    }
    
    
    /**
     * Provides access to the header cache of the top wrapper.
     *
     * @return The map of cached headers.
     */
    public Map getHeaders() {
        return m_headers;
    }    
    
    /**
     * Adds some bytes to the list of include results. 
     * Should be used only in inclusion-scenarios 
     * like the JSP cms:include tag processing.
     * 
     * @param result The byte array to add
     */
    public void addToIncludeResults(byte[] result) {
        if (m_includeResults == null) {
            m_includeResults = new ArrayList(10);
        }
        m_includeResults.add(result);
    }
        
    
    /** 
     * Adds an inclusion target to the list of include results.
     * Should be used only in inclusion-scenarios
     * like the JSP cms:include tag processing.
     *
     * @param target The include target name to add
     */
    public void addToIncludeList(String target) {
        if (m_includeList == null) {
            m_includeList = new ArrayList(10);
        }
        m_includeList.add(target);
    }
    
    /**
     * Is used to check if the response has an include list, 
     * which indicates a) it is probalbly processing a JSP element 
     * and b) it can never be streamed and alwys must be buffered.
     *
     * @return true if this response has an include list, false otherwise
     */
    public boolean hasIncludeList() {
        return m_includeList != null;
    }