001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.activemq.transaction;
018    
019    import java.io.IOException;
020    import java.io.InterruptedIOException;
021    import java.util.ArrayList;
022    import java.util.Collections;
023    import java.util.Iterator;
024    import java.util.concurrent.Callable;
025    import java.util.concurrent.ExecutionException;
026    import java.util.concurrent.FutureTask;
027    import javax.transaction.xa.XAException;
028    import org.apache.activemq.command.TransactionId;
029    import org.slf4j.Logger;
030    
031    /**
032     * Keeps track of all the actions the need to be done when a transaction does a
033     * commit or rollback.
034     * 
035     * 
036     */
037    public abstract class Transaction {
038    
039        public static final byte START_STATE = 0; // can go to: 1,2,3
040        public static final byte IN_USE_STATE = 1; // can go to: 2,3
041        public static final byte PREPARED_STATE = 2; // can go to: 3
042        public static final byte FINISHED_STATE = 3;
043    
044        private final ArrayList<Synchronization> synchronizations = new ArrayList<Synchronization>();
045        private byte state = START_STATE;
046        protected FutureTask<?> preCommitTask = new FutureTask<Object>(new Callable<Object>() {
047            public Object call() throws Exception {
048                doPreCommit();
049                return null;
050            }   
051        });
052        protected FutureTask<?> postCommitTask = new FutureTask<Object>(new Callable<Object>() {
053            public Object call() throws Exception {
054                doPostCommit();
055                return null;
056            }   
057        });
058        
059        public byte getState() {
060            return state;
061        }
062    
063        public void setState(byte state) {
064            this.state = state;
065        }
066    
067        public void addSynchronization(Synchronization r) {
068            synchronizations.add(r);
069            if (state == START_STATE) {
070                state = IN_USE_STATE;
071            }
072        }
073    
074        public void removeSynchronization(Synchronization r) {
075            synchronizations.remove(r);
076        }
077    
078        public void prePrepare() throws Exception {
079    
080            // Is it ok to call prepare now given the state of the
081            // transaction?
082            switch (state) {
083            case START_STATE:
084            case IN_USE_STATE:
085                break;
086            default:
087                XAException xae = new XAException("Prepare cannot be called now.");
088                xae.errorCode = XAException.XAER_PROTO;
089                throw xae;
090            }
091    
092            // // Run the prePrepareTasks
093            // for (Iterator iter = prePrepareTasks.iterator(); iter.hasNext();) {
094            // Callback r = (Callback) iter.next();
095            // r.execute();
096            // }
097        }
098        
099        protected void fireBeforeCommit() throws Exception {
100            for (Iterator<Synchronization> iter = synchronizations.iterator(); iter.hasNext();) {
101                Synchronization s = iter.next();
102                s.beforeCommit();
103            }
104        }
105    
106        protected void fireAfterCommit() throws Exception {
107            for (Iterator<Synchronization> iter = synchronizations.iterator(); iter.hasNext();) {
108                Synchronization s = iter.next();
109                s.afterCommit();
110            }
111        }
112    
113        public void fireAfterRollback() throws Exception {
114            Collections.reverse(synchronizations);
115            for (Iterator<Synchronization> iter = synchronizations.iterator(); iter.hasNext();) {
116                Synchronization s = iter.next();
117                s.afterRollback();
118            }
119        }
120    
121        @Override
122        public String toString() {
123            return super.toString() + "[synchronizations=" + synchronizations + "]";
124        }
125    
126        public abstract void commit(boolean onePhase) throws XAException, IOException;
127    
128        public abstract void rollback() throws XAException, IOException;
129    
130        public abstract int prepare() throws XAException, IOException;
131    
132        public abstract TransactionId getTransactionId();
133    
134        public abstract Logger getLog();
135        
136        public boolean isPrepared() {
137            return getState() == PREPARED_STATE;
138        }
139        
140        public int size() {
141            return synchronizations.size();
142        }
143        
144        protected void waitPostCommitDone(FutureTask<?> postCommitTask) throws XAException, IOException {
145            try {
146                postCommitTask.get();
147            } catch (InterruptedException e) {
148                throw new InterruptedIOException(e.toString());
149            } catch (ExecutionException e) {
150                Throwable t = e.getCause();
151                if (t instanceof XAException) {
152                    throw (XAException) t;
153                } else if (t instanceof IOException) {
154                    throw (IOException) t;
155                } else {
156                    throw new XAException(e.toString());
157                }
158            }    
159        }
160        
161        protected void doPreCommit() throws XAException {
162            try {
163                fireBeforeCommit();
164            } catch (Throwable e) {
165                // I guess this could happen. Post commit task failed
166                // to execute properly.
167                getLog().warn("PRE COMMIT FAILED: ", e);
168                XAException xae = new XAException("PRE COMMIT FAILED");
169                xae.errorCode = XAException.XAER_RMERR;
170                xae.initCause(e);
171                throw xae;
172            }
173        }
174    
175        protected void doPostCommit() throws XAException {
176            try {
177                fireAfterCommit();
178            } catch (Throwable e) {
179                // I guess this could happen. Post commit task failed
180                // to execute properly.
181                getLog().warn("POST COMMIT FAILED: ", e);
182                XAException xae = new XAException("POST COMMIT FAILED");
183                xae.errorCode = XAException.XAER_RMERR;
184                xae.initCause(e);
185                throw xae;
186            }
187        }
188    }