ASF_20_SRC_AUTO/src/blocks/jsp/java/org/apache/cocoon/generation/JSPGenerator.java

/*
 * Copyright 1999-2004 The Apache Software Foundation.
 * 
 * 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.apache.cocoon.generation;

import org.apache.cocoon.ProcessingException;
import org.apache.cocoon.components.jsp.JSPEngine;
import org.apache.cocoon.environment.ObjectModelHelper;
import org.apache.cocoon.environment.http.HttpEnvironment;
import org.apache.excalibur.xml.sax.SAXParser;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.ByteArrayInputStream;
import java.io.IOException;

/**
 * Allows Servlets and JSPs to be used as a generator.
 *
 * @author <a href="mailto:dims@yahoo.com">Davanum Srinivas</a>
 * @version CVS $Id: JSPGenerator.java,v 1.3 2004/03/05 13:01:57 bdelacretaz Exp $
 */
public class JSPGenerator extends ServiceableGenerator {

    /**
     * Generate XML data from JSPEngine output.
     */
    public void generate() throws ProcessingException {

        final HttpServletResponse servletResponse =
            (HttpServletResponse) this.objectModel.get(HttpEnvironment.HTTP_RESPONSE_OBJECT);
        final HttpServletRequest servletRequest =
            (HttpServletRequest) this.objectModel.get(HttpEnvironment.HTTP_REQUEST_OBJECT);
        final ServletContext servletContext =
            (ServletContext) this.objectModel.get(HttpEnvironment.HTTP_SERVLET_CONTEXT);

        // ensure that we are running in a servlet environment
        if (servletResponse == null || servletRequest == null || servletContext == null) {
            throw new ProcessingException("JSPReader can only be used from within a Servlet environment.");
        }

        JSPEngine engine = null;
        SAXParser parser = null;
        try {
            // TODO (KP): Should we exclude not supported protocols, say 'context'?
            String url = super.source;
            // absolute path is processed as is
            if (!url.startsWith("/")) {
                // get current request path
                String servletPath = servletRequest.getServletPath();
                // remove sitemap URI part
                String sitemapURI = ObjectModelHelper.getRequest(objectModel).getSitemapURI();
                if (sitemapURI != null) {
                    servletPath = servletPath.substring(0, servletPath.indexOf(sitemapURI));
                } else {
                    // for example when using cocoon:/ pseudo protocol
                    servletPath = servletPath.substring(0, servletPath.lastIndexOf("/") + 1);
                }
                url = servletPath + url;
            }

            engine = (JSPEngine) super.manager.lookup(JSPEngine.ROLE);

            if (getLogger().isDebugEnabled()) {
                getLogger().debug("JSPGenerator executing:" + url);
            }

            byte[] bytes = engine.executeJSP(url, servletRequest, servletResponse, servletContext);

            InputSource input = new InputSource(new ByteArrayInputStream(bytes));
            // utf-8 is default encoding; specified explicitely here as a reminder.
            input.setEncoding("utf-8");

            // pipe the results into the parser
            parser = (SAXParser) super.manager.lookup(SAXParser.ROLE);
            parser.parse(input, super.xmlConsumer);
        } catch (ServletException e) {
            throw new ProcessingException("ServletException while executing JSPEngine", e);
        } catch (SAXException e) {
            throw new ProcessingException("SAXException while parsing JSPEngine output", e);
        } catch (IOException e) {
            throw new ProcessingException("IOException JSPGenerator.generate()", e);
        } catch (ProcessingException e) {
            throw e;
        } catch (Exception e) {
            throw new ProcessingException("Exception JSPGenerator.generate()", e);
        } finally {
            super.manager.release(parser);
            super.manager.release(engine);
        }
    }
}