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.ShutdownRunningTask; 020 021/** 022 * Allows {@link org.apache.camel.Consumer} to fine grained control on shutdown which mostly 023 * have to cater for in-memory based components. These components need to be able to have an extra 024 * chance to have their pending exchanges being completed to support graceful shutdown. This helps 025 * ensure that no messages get lost. 026 * 027 * @version 028 * @see org.apache.camel.spi.ShutdownStrategy 029 */ 030public interface ShutdownAware extends ShutdownPrepared { 031 032 /** 033 * To defer shutdown during first phase of shutdown. This allows any pending exchanges to be completed 034 * and therefore ensure a graceful shutdown without loosing messages. At the very end when there are no 035 * more inflight and pending messages the consumer could then safely be shutdown. 036 * <p/> 037 * This is needed by {@link org.apache.camel.component.seda.SedaConsumer}. 038 * 039 * @param shutdownRunningTask the configured option for how to act when shutting down running tasks. 040 * @return <tt>true</tt> to defer shutdown to very last. 041 */ 042 boolean deferShutdown(ShutdownRunningTask shutdownRunningTask); 043 044 /** 045 * Gets the number of pending exchanges. 046 * <p/> 047 * Some consumers has internal queues with {@link org.apache.camel.Exchange} which are pending. 048 * For example the {@link org.apache.camel.component.seda.SedaConsumer}. 049 * <p/> 050 * Return <tt>zero</tt> to indicate no pending exchanges and therefore ready to shutdown. 051 * 052 * @return number of pending exchanges 053 */ 054 int getPendingExchangesSize(); 055 056}