001/* 002 * Copyright 2006-2007 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016package org.springframework.batch.integration.async; 017 018import org.springframework.batch.core.StepExecution; 019import org.springframework.batch.core.scope.context.StepContext; 020import org.springframework.batch.core.scope.context.StepSynchronizationManager; 021import org.springframework.integration.support.MessageBuilder; 022import org.springframework.messaging.Message; 023import org.springframework.messaging.MessageChannel; 024import org.springframework.messaging.support.ChannelInterceptor; 025import org.springframework.messaging.support.ChannelInterceptorAdapter; 026 027/** 028 * A {@link ChannelInterceptor} that adds the current {@link StepExecution} (if 029 * there is one) as a header to the message. Downstream asynchronous handlers 030 * can then take advantage of the step context without needing to be step 031 * scoped, which is a problem for handlers executing in another thread because 032 * the scope context is not available. 033 * 034 * @author Dave Syer 035 * 036 */ 037public class StepExecutionInterceptor extends ChannelInterceptorAdapter { 038 039 /** 040 * The name of the header 041 */ 042 public static final String STEP_EXECUTION = "stepExecution"; 043 044 @Override 045 public Message<?> preSend(Message<?> message, MessageChannel channel) { 046 StepContext context = StepSynchronizationManager.getContext(); 047 if (context == null) { 048 return message; 049 } 050 return MessageBuilder.fromMessage(message).setHeader(STEP_EXECUTION, context.getStepExecution()).build(); 051 } 052 053}