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.camel.spi;
018    
019    import org.apache.camel.Exchange;
020    import org.apache.camel.Message;
021    
022    /**
023     * An object representing the unit of work processing an {@link Exchange}
024     * which allows the use of {@link Synchronization} hooks. This object might map one-to-one with
025     * a transaction in JPA or Spring; or might not.
026     *
027     * @version $Revision: 792966 $
028     */
029    public interface UnitOfWork {
030    
031        /**
032         * Adds a synchronization hook
033         *
034         * @param synchronization  the hook
035         */
036        void addSynchronization(Synchronization synchronization);
037    
038        /**
039         * Removes a synchronization hook
040         *
041         * @param synchronization  the hook
042         */
043        void removeSynchronization(Synchronization synchronization);
044    
045        /**
046         * Handover all the registered synchronizations to the target {@link org.apache.camel.Exchange}.
047         * <p/>
048         * This is used when a route turns into asynchronous and the {@link org.apache.camel.Exchange} that
049         * is continued and routed in the async thread should do the on completion callbacks instead of the
050         * original synchronous thread.
051         * 
052         * @param target  the target exchange
053         */
054        void handoverSynchronization(Exchange target);
055    
056        /**
057         * Invoked when this unit of work has been completed, whether it has failed or completed
058         *
059         * @param exchange the current exchange
060         */
061        void done(Exchange exchange);
062    
063        /**
064         * Returns the unique ID of this unit of work, lazily creating one if it does not yet have one
065         * 
066         * @return the unique ID
067         */
068        String getId();
069    
070        /**
071         * Gets the original IN {@link Message} this Unit of Work was started with.
072         *
073         * @return the original IN {@link Message}
074         */
075        Message getOriginalInMessage();
076    }