Tomcat example source code file (TwoPhaseCommitInterceptor.java)

This example Tomcat source code file (TwoPhaseCommitInterceptor.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

channelexception, channelmessage, channelmessage, end_data, hashmap, hashmap, id, mapentry, mapentry, received, start_data, unable, uniqueid, uniqueid, util

The Tomcat TwoPhaseCommitInterceptor.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.catalina.tribes.group.interceptors;

import java.util.HashMap;

import org.apache.catalina.tribes.ChannelException;
import org.apache.catalina.tribes.ChannelMessage;
import org.apache.catalina.tribes.Member;
import org.apache.catalina.tribes.group.ChannelInterceptorBase;
import org.apache.catalina.tribes.group.InterceptorPayload;
import org.apache.catalina.tribes.util.UUIDGenerator;
import org.apache.catalina.tribes.util.Arrays;
import org.apache.catalina.tribes.UniqueId;
import java.util.Map;

/**
 * <p>Title: 

 *
 * <p>Description: 

 *
 * <p>Company: 

 *
 * @author not attributable
 * @version 1.0
 */
public class TwoPhaseCommitInterceptor extends ChannelInterceptorBase {

    public static final byte[] START_DATA = new byte[] {113, 1, -58, 2, -34, -60, 75, -78, -101, -12, 32, -29, 32, 111, -40, 4};
    public static final byte[] END_DATA = new byte[] {54, -13, 90, 110, 47, -31, 75, -24, -81, -29, 36, 52, -58, 77, -110, 56};
    private static org.apache.juli.logging.Log log = org.apache.juli.logging.LogFactory.getLog(TwoPhaseCommitInterceptor.class);

    protected HashMap messages = new HashMap();
    protected long expire = 1000 * 60; //one minute expiration
    protected boolean deepclone = true;

    public void sendMessage(Member[] destination, ChannelMessage msg, InterceptorPayload payload) throws
        ChannelException {
        //todo, optimize, if destination.length==1, then we can do
        //msg.setOptions(msg.getOptions() & (~getOptionFlag())
        //and just send one message
        if (okToProcess(msg.getOptions()) ) {
            super.sendMessage(destination, msg, null);
            ChannelMessage confirmation = null;
            if ( deepclone ) confirmation = (ChannelMessage)msg.deepclone();
            else confirmation = (ChannelMessage)msg.clone();
            confirmation.getMessage().reset();
            UUIDGenerator.randomUUID(false,confirmation.getUniqueId(),0);
            confirmation.getMessage().append(START_DATA,0,START_DATA.length);
            confirmation.getMessage().append(msg.getUniqueId(),0,msg.getUniqueId().length);
            confirmation.getMessage().append(END_DATA,0,END_DATA.length);
            super.sendMessage(destination,confirmation,payload);
        } else {
            //turn off two phase commit
            //this wont work if the interceptor has 0 as a flag
            //since there is no flag to turn off
            //msg.setOptions(msg.getOptions() & (~getOptionFlag()));
            super.sendMessage(destination, msg, payload);
        }
    }

    public void messageReceived(ChannelMessage msg) {
        if (okToProcess(msg.getOptions())) {
            if ( msg.getMessage().getLength() == (START_DATA.length+msg.getUniqueId().length+END_DATA.length) &&
                 Arrays.contains(msg.getMessage().getBytesDirect(),0,START_DATA,0,START_DATA.length) &&
                 Arrays.contains(msg.getMessage().getBytesDirect(),START_DATA.length+msg.getUniqueId().length,END_DATA,0,END_DATA.length) ) {
                UniqueId id = new UniqueId(msg.getMessage().getBytesDirect(),START_DATA.length,msg.getUniqueId().length);
                MapEntry original = (MapEntry)messages.get(id);
                if ( original != null ) {
                    super.messageReceived(original.msg);
                    messages.remove(id);
                } else log.warn("Received a confirmation, but original message is missing. Id:"+Arrays.toString(id.getBytes()));
            } else {
                UniqueId id = new UniqueId(msg.getUniqueId());
                MapEntry entry = new MapEntry((ChannelMessage)msg.deepclone(),id,System.currentTimeMillis());
                messages.put(id,entry);
            }
        } else {
            super.messageReceived(msg);
        }
    }

    public boolean getDeepclone() {
        return deepclone;
    }

    public long getExpire() {
        return expire;
    }

    public void setDeepclone(boolean deepclone) {
        this.deepclone = deepclone;
    }

    public void setExpire(long expire) {
        this.expire = expire;
    }
    
    public void heartbeat() {
        try {
            long now = System.currentTimeMillis();
            Map.Entry[] entries = (Map.Entry[])messages.entrySet().toArray(new Map.Entry[messages.size()]);
            for (int i=0; i<entries.length; i++ ) {
                MapEntry entry = (MapEntry)entries[i].getValue();
                if ( entry.expired(now,expire) ) {
                    if(log.isInfoEnabled())
                        log.info("Message ["+entry.id+"] has expired. Removing.");
                    messages.remove(entry.id);
                }//end if
            }
        } catch ( Exception x ) {
            log.warn("Unable to perform heartbeat on the TwoPhaseCommit interceptor.",x);
        } finally {
            super.heartbeat();
        }
    }
    
    public static class MapEntry {
        public ChannelMessage msg;
        public UniqueId id;
        public long timestamp;
        
        public MapEntry(ChannelMessage msg, UniqueId id, long timestamp) {
            this.msg = msg;
            this.id = id;
            this.timestamp = timestamp;
        }
        public boolean expired(long now, long expiration) {
            return (now - timestamp ) > expiration;
        }

    }

}