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.processor.idempotent;
018    
019    /**
020     * Access to a repository of Message IDs to implement the
021     * <a href="http://activemq.apache.org/camel/idempotent-consumer.html">Idempotent Consumer</a> pattern.
022     *
023     * @version $Revision: 303 $
024     */
025    public interface MessageIdRepository {
026    
027        /**
028         * Returns true if this messageId has been processed before
029         * otherwise this messageId is added to the repository and false is returned.
030         *
031         * @param messageId the String ID of the message
032         * @return true if the message has been processed succesfully before otherwise false
033         */
034        boolean contains(String messageId);
035    }