001/**
002 *   GRANITE DATA SERVICES
003 *   Copyright (C) 2006-2013 GRANITE DATA SERVICES S.A.S.
004 *
005 *   This file is part of the Granite Data Services Platform.
006 *
007 *   Granite Data Services is free software; you can redistribute it and/or
008 *   modify it under the terms of the GNU Lesser General Public
009 *   License as published by the Free Software Foundation; either
010 *   version 2.1 of the License, or (at your option) any later version.
011 *
012 *   Granite Data Services is distributed in the hope that it will be useful,
013 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
014 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
015 *   General Public License for more details.
016 *
017 *   You should have received a copy of the GNU Lesser General Public
018 *   License along with this library; if not, write to the Free Software
019 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
020 *   USA, or see <http://www.gnu.org/licenses/>.
021 */
022package org.granite.gravity.tomcat;
023
024import java.io.IOException;
025import java.io.InputStream;
026
027import javax.servlet.ServletException;
028import javax.servlet.http.HttpServletRequest;
029import javax.servlet.http.HttpServletResponse;
030
031import org.apache.catalina.CometEvent;
032import org.apache.catalina.CometProcessor;
033import org.granite.gravity.AbstractGravityServlet;
034import org.granite.logging.Logger;
035
036/**
037 * @author Franck WOLFF
038 */
039public abstract class AbstractCometProcessor extends AbstractGravityServlet implements CometProcessor {
040
041    ///////////////////////////////////////////////////////////////////////////
042    // Fields.
043
044    private static final long serialVersionUID = 1L;
045    private static final Logger log = Logger.getLogger(AbstractCometProcessor.class);
046    
047    private boolean longPollingTimeoutSupported = true;
048
049    ///////////////////////////////////////////////////////////////////////////
050    // Abstract methods.
051
052        public abstract CometIO createCometIO();
053        
054    public abstract boolean handleRequest(CometEvent event, InputStream content)
055        throws IOException, ServletException;
056
057    public abstract boolean handleEnd(CometEvent event)
058        throws IOException, ServletException;
059
060    public abstract boolean handleError(CometEvent event)
061        throws IOException, ServletException;
062
063    ///////////////////////////////////////////////////////////////////////////
064    // CometProcessor implementation.
065
066    public void event(CometEvent event) throws IOException, ServletException {
067        
068        // make sure we've got a valid CometEvent (should never happen)
069        if (!EventUtil.isValid(event)) {
070                log.error("Tomcat sent an invalid CometEvent: %s.%s", event.getEventType(), event.getEventSubType());
071                return;
072        }
073
074        if (log.isDebugEnabled()) {
075                log.debug(
076                    "%s.%s: %s/%s",
077                    event.getEventType(), event.getEventSubType(),
078                    event.getHttpServletRequest(), event.getHttpServletResponse()
079                );
080        }
081
082        if (event.getEventType() == CometEvent.EventType.BEGIN)
083            begin(event);
084        else if (event.getEventType() == CometEvent.EventType.READ)
085            read(event);
086        else if (event.getEventType() == CometEvent.EventType.END)
087            end(event);
088        else if (event.getEventType() == CometEvent.EventType.ERROR)
089            error(event);
090        else
091            throw new ServletException("Unknown CometEvent type: " + event.getEventType());
092    }
093
094    ///////////////////////////////////////////////////////////////////////////
095    // Comet events processing.
096
097    protected void begin(CometEvent event) throws IOException, ServletException {
098        boolean close = true;
099        try {
100                // Event timeout isn't supported with APR connectors...
101                if (longPollingTimeoutSupported) {
102                        try {
103                                event.setTimeout((int)getLongPollingTimeout());
104                        }
105                        catch (Exception e) {
106                                longPollingTimeoutSupported = false;
107                        }
108                }
109
110                HttpServletRequest request = event.getHttpServletRequest();
111            CometIO io = createCometIO();
112                io.readFully(request.getInputStream());
113                request.getParameter("");       // Patch GDS-495
114                
115                close = handleRequest(event, io.getInputStream());
116        }
117        finally {
118                if (close) {
119                try {
120                        event.close();
121                } catch (Exception e) {
122                        log.debug(e, "Could not close event: %s", EventUtil.toString(event));
123                }
124                }
125        }
126    }
127
128        protected void read(CometEvent event) {
129                // This implementation doesn't use asynchronous reads.
130                throw new RuntimeException("Unsupported operation");
131    }
132    
133        protected void end(CometEvent event) throws IOException, ServletException {
134                boolean close = true;
135                try {
136                        close = handleEnd(event);
137                }
138                finally {
139                        if (close) {
140                        try {
141                                event.close();
142                        } catch (Exception e) {
143                                log.debug(e, "Could not close event: %s", EventUtil.toString(event));
144                        }
145                        }
146        }
147    }
148    
149    protected void error(CometEvent event) throws IOException, ServletException {
150        boolean close = true;
151        try {
152                close = handleError(event);
153        }
154        finally {
155                if (close) {
156                        try {
157                                event.close();
158                        } catch (Exception e) {
159                                log.debug(e, "Could not close event: %s", EventUtil.toString(event));
160                        }
161                }
162        }
163    }
164
165    ///////////////////////////////////////////////////////////////////////////
166    // Utility.
167
168    @Override
169    protected void service(HttpServletRequest request, HttpServletResponse response)
170        throws IOException, ServletException {
171        throw new ServletException("Not in a valid Comet configuration (use an APR or NIO connector)");
172    }
173}