huber 02/04/21 13:06:42
Added: src/scratchpad/src/org/apache/cocoon/servlet
CocoonFilterGeneratorImpl.java
Log:
A Servlet2.3 Filter, do Cocoon post-processing, usable for
JSP/Servlets generating XML, doing post-processing using Cocoon
Revision Changes Path
1.1
xml-cocoon2/src/scratchpad/src/org/apache/cocoon/servlet/CocoonFilterGeneratorImpl.java
Index: CocoonFilterGeneratorImpl.java
===================================================================
/*
* ============================================================================
* The Apache Software License, Version 1.1
* ============================================================================
* Copyright (C) 1999-2002 The Apache Software Foundation. All rights reserved.
* Redistribution and use in source and binary forms, with or without modifica-
* tion, 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 acknowledgment: "This product includes software
* developed by the Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowledgment may appear in the software itself, if
* and wherever such third-party acknowledgments normally appear.
* 4. The names "Apache Cocoon" 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
* [EMAIL PROTECTED]
* 5. Products derived from this software may not be called "Apache", nor may
* "Apache" appear in their name, without prior written permission of the
* Apache Software Foundation.
* 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 (INCLU-
* DING, 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 and was originally created by
* Stefano Mazzocchi <[EMAIL PROTECTED]>. For more information on the Apache
* Software Foundation, please see <http://www.apache.org/>.
*/
package org.apache.cocoon.servlet;
import java.io.*;
import java.util.Enumeration;
import javax.servlet.*;
import javax.servlet.http.*;
/**
* This class implements a Servlet 2.3 Cocoon post-processing filter.
* <p>
* First all filters of the filter chain are processed.
* As a final filter processing step a Cocoon servlet processing is
* done.
* In most cases you may want to use this filter for JSP pre-processing,
* and Cocoon post-processing. You may use this filter not only for
* JSP pre-processing, but you can define any servlet/filter-chain for
* the pre-processing.
* </p>
* <p>
* Xml-data of the filters are passed to cocoon via a request attribute.
* On Cocoon side the RequestAttributeGenerator will pick the xml-data, and
* normal cocoon pipeline processing is done.
* </p>
* <p>
* Using this filter you have to setup a filter, and a filter mapping
* in the webapp deployment descriptor.
* </p>
* <p>
* In the cocoon sitemap you have to setup the <code>RequestAttributeGenerator
* </code>. The pipeline setup should match the request URI, and it
* should use the <code>RequestAttributeGenerator</code> as its generator.
* </p>
* <p>
* A sample web.xml snippet:
* </p>
* <pre><tt>
* <filter>
* <filter-name>CocoonFilterGenerator</filter-name>
* <display-name>CocoonFilterGenerator</display-name>
* <description>Run JSP/Servlet processing before feeding into
Cocoon</description>
*
<filter-class>org.apache.cocoon.servlet.CocoonFilterGeneratorImpl</filter-class>
* <init-param>
* <param-name>cocoon-servlet-class-name</param-name>
*
<param-value>org.apache.cocoon.servlet.CocoonServlet</param-value>
* </init-param>
* <init-param>
* <param-name>verbose</param-name>
* <param-value>true</param-value>
* </init-param>
* </filter>
* <filter-mapping>
* <filter-name>CocoonFilterGenerator</filter-name>
* <url-pattern>*.jsp</url-pattern>
* </filter-mapping>
* </tt></pre>
* <p>
* A simple sitemap snippet:
* </p>
* <pre><tt>
* <map:match pattern="docs/samples/jsp/*">
* <map:generate type="req-attr"/>
* <map:transform src="stylesheets/page/simple-page2html.xsl">
* <map:parameter name="view-source" value="docs/samples/jsp/{1}"/>
* <!--
* Run-time configuration is done through these
* <map:parameter/> elements. Again, let's have a look at the
* javadocs:
* "[...] All <map:parameter> declarations will be made
* available in the XSLT stylesheet as xsl:variables. [...]"
* -->
* </map:transform>
* <map:serialize/>
* </map:match>
* </tt></pre>
* <p>
* Conclusion of this example: The request URI
* <code>/cocoon/docs/samples/jsp/hello.jsp</code> is processed
* by the filter <code>CocoonFilterGenerator</code>, due to the
* filter-mapping matching.
* The pipeline of the snippet matches the request, and the
* <code>req-attr</code> generator picks the xml-data of the filter-processing
* and sends it into the cocoon pipeline.
* </p>
*
* @author <a href="mailto:[EMAIL PROTECTED]";>Bernhard Huber</a>
* @version CVS $Id: CocoonFilterGeneratorImpl.java,v 1.1 2002/04/21
20:06:42 huber Exp $
* @servlet:filter-name CocoonFilterGeneratorImpl
*/
public class CocoonFilterGeneratorImpl implements Filter {
/**
* Specifies the name of the filter configuration,
* definig the Cocoon servlet class name, ie
<code>cocoon-servlet-class-name</code>
*
* @since 1.0
*/
public final static String COCOON_SERVLET_CLASS_NAME_PARAM =
"cocoon-servlet-class-name";
/**
* Specifies the Cocoon servlet class name default value,
* ie <code>org.apache.cocoon.servlet.CocoonServlet</code>.
*
* @since 1.0
*/
public final static String COCOON_SERVLET_CLASS_NAME_DEFAULT =
"org.apache.cocoon.servlet.CocoonServlet";
/**
* Name of filter parameter for setting up verbose mode
*
* @since 1.0
*/
final String VERBOSE_PARAM = "verbose";
/**
* Default verbose mode, ie <code>true</code>.
*
* @since 1.0
*/
final boolean VERBOSE_DEFAULT = true;
/**
* Currently active verbose mode
*
* @since 1.0
*/
private boolean verbose = false;
/**
* filter wide cocoon servlet to use
*
* @since 1.0
*/
private Servlet cocoon = null;
/**
* the filter configuration currently used.
*
* @since 1.0
*/
private FilterConfig filterConfig;
/**
* Sets the filterConfig attribute of the JSPFilterImpl object
*
* @param cfg The new filterConfig value
* @since 1.0
*/
public void setFilterConfig(FilterConfig cfg) {
filterConfig = cfg;
logFilterConfig();
String value;
value = filterConfig.getInitParameter(VERBOSE_PARAM);
if (value != null) {
verbose = ("true".compareToIgnoreCase(value) == 0);
} else {
verbose = VERBOSE_DEFAULT;
}
}
/**
* Gets the filterConfig attribute of the JSPFilterImpl object
*
* @return The filterConfig value
* @since 1.0
*/
public FilterConfig getFilterConfig() {
return filterConfig;
}
/**
* callback method, destroying the filter
* <p>
* If cocoon servlet is defined, destroy it.
* </p>
*
* @since 1.0
*/
public void destroy() {
if (cocoon != null) {
cocoon.destroy();
cocoon = null;
}
}
/**
* do the filter processing.
* <p>
* The sequence of this filter:
* </p>
* <ol>
* <li>Process filters defined in the filter chain</li>
* <li>Use cocoon as final processing step</li>
* </ol>
*
* @param req the http request
* @param res the final http response
* @param fc the filter chain
* @exception java.io.IOException reading/writing failed
* @exception javax.servlet.ServletException processing failed
* @since 1.0
*/
public void doFilter(ServletRequest req, ServletResponse res, FilterChain fc)
throws java.io.IOException, javax.servlet.ServletException {
log("doFilter...");
if (verbose) {
logServletContext();
}
CocoonFilterGeneratorResponseWrapper res_wrapper1 = new
CocoonFilterGeneratorResponseWrapper((HttpServletResponse) res);
// start filtering, process filter chain
log("do filter pre-processing...");
fc.doFilter(req, res_wrapper1);
// put response of pre-processing into request attribute
byte[] res_wrapper_data;
log("get xml-data...");
res_wrapper_data = res_wrapper1.getData();
if (verbose) {
log("get xml-data: " + new String(res_wrapper_data));
log("store xml-data in request-attr " +
CocoonFilterGeneratorRequestWrapper.XML_DATA_ATTR);
}
CocoonFilterGeneratorRequestWrapper cfgrw = new
CocoonFilterGeneratorRequestWrapper((HttpServletRequest) req);
cfgrw.setXMLData(res_wrapper_data);
// invoke Cocoon now
try {
log("create Cocoon instance...");
createCocoonInstance();
log("service using Cocoon instance...");
cocoon.service(cfgrw, res);
} catch (Exception e) {
throw new ServletException("Cannot post-process using Cocoon", e);
}
}
/**
* Gets the cocoonServletClassName
* <p>
* The cocoon servlet class name can be configured in the
* filter configurarion.
* </p>
*
* @return The cocoonServletClassName value
* @since 1.0
* @see #COCOON_SERVLET_CLASS_NAME_PARAM
* @see #COCOON_SERVLET_CLASS_NAME_DEFAULT
*/
protected String getCocoonServletClassName() {
String clazz_name = filterConfig.getInitParameter(
COCOON_SERVLET_CLASS_NAME_PARAM);
if (clazz_name == null) {
clazz_name = COCOON_SERVLET_CLASS_NAME_DEFAULT;
}
return clazz_name;
}
/**
* Gets the verbose attribute of the CocoonFilterGeneratorImpl object
*
* @return The verbose value
* @since 1.0
*/
protected boolean isVerbose() {
return verbose;
}
/**
* create Cocoon servlet instance.
*
* @return The cocoonInstance value
* @exception ClassNotFoundException Cocoon servlet class is not available
* @exception InstantiationException failed to instaniate Cocoon servlet class
* @exception IllegalAccessException initializing of Cocoon servlet instance
* failed
* @exception ServletException initializing of Cocoon servlet instance
* failed
* @since 1.0
*/
protected Servlet createCocoonInstance() throws ClassNotFoundException,
InstantiationException, IllegalAccessException, ServletException {
String clazz_name = getCocoonServletClassName();
Class clazz =
Thread.currentThread().getContextClassLoader().loadClass(clazz_name);
if (cocoon == null) {
cocoon = (Servlet) clazz.newInstance();
cocoon.init(new
CocoonFilterGeneratorConfig(filterConfig.getServletContext()));
}
return cocoon;
}
/**
* log message to servlet context log
*
* @param s message to log
* @since 1.0
*/
protected void log(String s) {
filterConfig.getServletContext().log("[" + this.getClass().getName() + "] "
+ String.valueOf(s));
//System.out.println("[" + this.getClass().getName() + "] " +
String.valueOf(s));
}
/**
* Log all filter config parameter
*
* @since 1.0
*/
protected void logFilterConfig() {
log("filter config name " + filterConfig.getFilterName());
Enumeration names;
names = filterConfig.getInitParameterNames();
while (names.hasMoreElements()) {
String name = (String) names.nextElement();
Object value = filterConfig.getInitParameter(name);
log("filter config init parameter " +
"name " + String.valueOf(name) + ", " +
"value " + String.valueOf(value));
}
}
/**
* Log all servlet attribute, and parameters.
*
* @since 1.0
*/
protected void logServletContext() {
ServletContext context = filterConfig.getServletContext();
Enumeration names;
names = context.getAttributeNames();
while (names.hasMoreElements()) {
String name = (String) names.nextElement();
Object value = context.getAttribute(name);
log("context attribute " +
"name " + String.valueOf(name) + ", " +
"value " + String.valueOf(value));
}
names = context.getInitParameterNames();
while (names.hasMoreElements()) {
String name = (String) names.nextElement();
Object value = context.getInitParameter(name);
log("context init parameter " +
"name " + String.valueOf(name) + ", " +
"value " + String.valueOf(value));
}
}
/**
* Local request wrapper storing xml-data as a request-attribute.
*
* @author HuberB1
* @version
*/
class CocoonFilterGeneratorRequestWrapper extends HttpServletRequestWrapper {
/**
* put xml-data into request-attribute under this name, ie.
org.apache.cocoon.xml-data
*
* @since 1.0
*/
public final static String XML_DATA_ATTR = "org.apache.cocoon.xml-data";
/**
* Constructor for the CocoonGeneratorRequestWrapper object
*
* @param request Description of Parameter
* @since 1.0
*/
public CocoonFilterGeneratorRequestWrapper(HttpServletRequest request) {
super(request);
}
/**
* Sets the request attribute of the CocoonGeneratorRequestWrapper object
*
* @param xmlData The new xml-data value
* @since 1.0
*/
public void setXMLData(byte[] xmlData) {
setAttribute(XML_DATA_ATTR, xmlData);
}
/**
* Gets the xml-data from the request attribute
*
* @return The xml-data value
* @since 1.0
*/
public byte[] getXMLData() {
return (byte[]) getAttribute(XML_DATA_ATTR);
}
}
/**
* Stub implementation of Servlet Config
*
* @author HuberB1
* @version
*/
class CocoonFilterGeneratorConfig implements ServletConfig {
ServletContext c;
/**
* Constructor for the config object
*
* @param c The servlet context in use.
* @since 1.0
*/
public CocoonFilterGeneratorConfig(ServletContext c) {
this.c = c;
}
/**
* Gets the servletName attribute of the config object
*
* @return The servletName value
* @since 1.0
*/
public String getServletName() {
return "JSPEngineImpl";
}
/**
* Gets the initParameterNames attribute of the config object
*
* @return The initParameterNames value
* @since 1.0
*/
public Enumeration getInitParameterNames() {
return c.getInitParameterNames();
}
/**
* Gets the servletContext attribute of the config object
*
* @return The servletContext value
* @since 1.0
*/
public ServletContext getServletContext() {
return c;
}
/**
* Gets the initParameter attribute of the config object
*
* @param name Description of Parameter
* @return The initParameter value
* @since 1.0
*/
public String getInitParameter(String name) {
return null;
}
}
/**
* A response wrapper storing response in a byte array output stream.
*
* @author HuberB1
* @version
*/
class CocoonFilterGeneratorResponseWrapper extends HttpServletResponseWrapper {
private ByteArrayOutputStream output;
private int contentLength;
private String contentType;
/**
* Constructor for the GenericResponseWrapper object
*
* @param response Description of Parameter
* @since 1.0
*/
CocoonFilterGeneratorResponseWrapper(HttpServletResponse response) {
super(response);
output = new ByteArrayOutputStream();
}
/**
* Sets the contentType attribute of the GenericResponseWrapper object
*
* @param type The new contentType value
* @since 1.0
*/
public void setContentType(String type) {
this.contentType = type;
super.setContentType(type);
}
/**
* Gets the outputStream attribute of the GenericResponseWrapper object
*
* @return The outputStream value
* @since 1.0
*/
public ServletOutputStream getOutputStream() {
return new CocoonFilterGeneratorOutputStream(output);
}
/**
* Gets the data attribute of the GenericResponseWrapper object
*
* @return The data value
* @since 1.0
*/
public byte[] getData() {
return output.toByteArray();
}
/**
* Gets the writer attribute of the GenericResponseWrapper object
*
* @return The writer value
* @exception IOException Description of Exception
* @since 1.0
*/
public PrintWriter getWriter() throws IOException {
return new PrintWriter(getOutputStream(), true);
}
/**
* Gets the contentLength attribute of the GenericResponseWrapper object
*
* @return The contentLength value
* @since 1.0
*/
public int getContentLength() {
return contentLength;
}
/**
* Gets the contentType attribute of the GenericResponseWrapper object
*
* @return The contentType value
* @since 1.0
*/
public String getContentType() {
return contentType;
}
}
/**
* A servlet output stream storing output into a DataOutputStream.
*
* @author HuberB1
* @version
*/
class CocoonFilterGeneratorOutputStream extends ServletOutputStream {
private DataOutputStream stream;
/**
* Constructor for the FilterServletOutputStream object
*
* @param output Description of Parameter
* @since 1.0
*/
public CocoonFilterGeneratorOutputStream(OutputStream output) {
stream = new DataOutputStream(output);
}
/**
* Description of the Method
*
* @param b Description of Parameter
* @exception IOException Description of Exception
* @since 1.0
*/
public void write(int b) throws IOException {
stream.write(b);
}
/**
* Description of the Method
*
* @param b Description of Parameter
* @exception IOException Description of Exception
* @since 1.0
*/
public void write(byte[] b) throws IOException {
stream.write(b);
}
/**
* Description of the Method
*
* @param b Description of Parameter
* @param off Description of Parameter
* @param len Description of Parameter
* @exception IOException Description of Exception
* @since 1.0
*/
public void write(byte[] b, int off, int len) throws IOException {
stream.write(b, off, len);
}
}
}
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