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 /** 020 * Access to a repository of Message IDs to implement the 021 * <a href="http://camel.apache.org/idempotent-consumer.html">Idempotent Consumer</a> pattern. 022 * <p/> 023 * The <tt>add</tt> and <tt>contains</tt> methods is operating according to the {@link java.util.Set} contract. 024 * 025 * @version $Revision: 782534 $ 026 */ 027 public interface IdempotentRepository<E> { 028 029 /** 030 * Adds the key to the repository. 031 * 032 * @param key the key of the message for duplicate test 033 * @return <tt>true</tt> if this repository did <b>not</b> already contain the specified element 034 */ 035 boolean add(E key); 036 037 /** 038 * Returns <tt>true</tt> if this repository contains the specified element. 039 * 040 * @param key the key of the message 041 * @return <tt>true</tt> if this repository contains the specified element 042 */ 043 boolean contains(E key); 044 045 /** 046 * Removes the key from the repository. 047 * <p/> 048 * Is usually invoked if the exchange failed. 049 * 050 * @param key the key of the message for duplicate test 051 * @return <tt>true</tt> if the key was removed 052 */ 053 boolean remove(E key); 054 055 /** 056 * Confirms the key, after the exchange has been processed sucesfully. 057 * 058 * @param key the key of the message for duplicate test 059 * @return <tt>true</tt> if the key was confirmed 060 */ 061 boolean confirm(E key); 062 063 }