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 */ 017package org.apache.camel.spi; 018 019import org.apache.camel.Service; 020 021/** 022 * Access to a repository of Message IDs to implement the 023 * <a href="http://camel.apache.org/idempotent-consumer.html">Idempotent Consumer</a> pattern. 024 * <p/> 025 * The <tt>add</tt> and <tt>contains</tt> methods is operating according to the {@link java.util.Set} contract. 026 * <p/> 027 * The repository supports eager (default) and non-eager mode. 028 * <ul> 029 * <li>eager: calls <tt>add</tt> and <tt>confirm</tt> if complete, or <tt>remove</tt> if failed</li> 030 * <li>non-eager: calls <tt>contains</tt> and <tt>add</tt> if complete, or <tt>remove</tt> if failed</li> 031 * </ul> 032 * Notice the remove callback, can be configured to be disabled. 033 * <p/> 034 * Implementations for the <a href="http://camel.apache.org/idempotent-consumer.html">idempotent consumer EIP</a> 035 * should favor using {@link org.apache.camel.spi.ExchangeIdempotentRepository} instead. 036 * 037 * @version 038 * @see org.apache.camel.spi.ExchangeIdempotentRepository 039 */ 040public interface IdempotentRepository<E> extends Service { 041 042 /** 043 * Adds the key to the repository. 044 * <p/> 045 * <b>Important:</b> Read the class javadoc about eager vs non-eager mode. 046 * 047 * @param key the key of the message for duplicate test 048 * @return <tt>true</tt> if this repository did <b>not</b> already contain the specified element 049 */ 050 boolean add(E key); 051 052 /** 053 * Returns <tt>true</tt> if this repository contains the specified element. 054 * <p/> 055 * <b>Important:</b> Read the class javadoc about eager vs non-eager mode. 056 * 057 * @param key the key of the message 058 * @return <tt>true</tt> if this repository contains the specified element 059 */ 060 boolean contains(E key); 061 062 /** 063 * Removes the key from the repository. 064 * <p/> 065 * Is usually invoked if the exchange failed. 066 * <p/> 067 * <b>Important:</b> Read the class javadoc about eager vs non-eager mode. 068 * 069 * @param key the key of the message for duplicate test 070 * @return <tt>true</tt> if the key was removed 071 */ 072 boolean remove(E key); 073 074 /** 075 * Confirms the key, after the exchange has been processed successfully. 076 * <p/> 077 * <b>Important:</b> Read the class javadoc about eager vs non-eager mode. 078 * 079 * @param key the key of the message for duplicate test 080 * @return <tt>true</tt> if the key was confirmed 081 */ 082 boolean confirm(E key); 083 084 /** 085 * Clear the repository. 086 * <p/> 087 * <b>Important:</b> Read the class javadoc about eager vs non-eager mode. 088 */ 089 void clear(); 090 091}