org.springframework.integration.channel.interceptor.GlobalChannelInterceptorBeanPostProcessor.java Source code

Introduction

Here is the source code for org.springframework.integration.channel.interceptor.GlobalChannelInterceptorBeanPostProcessor.java

Source

/*
 * Copyright 2002-2010 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.integration.channel.interceptor;

import java.util.ArrayList;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.aop.framework.Advised;
import org.springframework.aop.support.AopUtils;
import org.springframework.beans.BeansException;
import org.springframework.beans.DirectFieldAccessor;
import org.springframework.beans.NotReadablePropertyException;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.core.OrderComparator;
import org.springframework.integration.MessageChannel;
import org.springframework.integration.channel.ChannelInterceptor;
import org.springframework.util.PatternMatchUtils;
import org.springframework.util.StringUtils;

/**
 * Will apply global interceptors to channels (<channel-interceptor>). 
 * 
 * @author Oleg Zhurakousky
 * @author Mark Fisher
 * @since 2.0
 */
final class GlobalChannelInterceptorBeanPostProcessor implements BeanPostProcessor, InitializingBean {

    private static final Log logger = LogFactory.getLog(GlobalChannelInterceptorBeanPostProcessor.class);

    private final OrderComparator comparator = new OrderComparator();

    private volatile List<GlobalChannelInterceptorWrapper> channelInterceptors;

    private final Set<GlobalChannelInterceptorWrapper> positiveOrderInterceptors = new LinkedHashSet<GlobalChannelInterceptorWrapper>();

    private final Set<GlobalChannelInterceptorWrapper> negativeOrderInterceptors = new LinkedHashSet<GlobalChannelInterceptorWrapper>();

    GlobalChannelInterceptorBeanPostProcessor(List<GlobalChannelInterceptorWrapper> channelInterceptors) {
        this.channelInterceptors = channelInterceptors;
    }

    public void afterPropertiesSet() throws Exception {
        for (GlobalChannelInterceptorWrapper channelInterceptor : this.channelInterceptors) {
            if (channelInterceptor.getOrder() >= 0) {
                this.positiveOrderInterceptors.add(channelInterceptor);
            } else {
                this.negativeOrderInterceptors.add(channelInterceptor);
            }
        }
    }

    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        return bean;
    }

    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        if (bean instanceof MessageChannel) {
            if (logger.isDebugEnabled()) {
                logger.debug("Applying global interceptors on channel '" + beanName + "'");
            }
            this.addMatchingInterceptors((MessageChannel) bean, beanName);
        }
        return bean;
    }

    /**
     * Adds any interceptor whose pattern matches against the channel's name. 
     */
    private void addMatchingInterceptors(MessageChannel channel, String beanName) {
        List<ChannelInterceptor> interceptors = this.getExistingInterceptors(channel);
        if (interceptors != null) {
            List<GlobalChannelInterceptorWrapper> tempInterceptors = new ArrayList<GlobalChannelInterceptorWrapper>();
            for (GlobalChannelInterceptorWrapper globalChannelInterceptorWrapper : this.positiveOrderInterceptors) {
                String[] patterns = globalChannelInterceptorWrapper.getPatterns();
                patterns = StringUtils.trimArrayElements(patterns);
                if (PatternMatchUtils.simpleMatch(patterns, beanName)) {
                    tempInterceptors.add(globalChannelInterceptorWrapper);
                }
            }
            Collections.sort(tempInterceptors, this.comparator);
            for (GlobalChannelInterceptorWrapper next : tempInterceptors) {
                interceptors.add(next.getChannelInterceptor());
            }
            tempInterceptors = new ArrayList<GlobalChannelInterceptorWrapper>();
            for (GlobalChannelInterceptorWrapper globalChannelInterceptorWrapper : this.negativeOrderInterceptors) {
                String[] patterns = globalChannelInterceptorWrapper.getPatterns();
                patterns = StringUtils.trimArrayElements(patterns);
                if (PatternMatchUtils.simpleMatch(patterns, beanName)) {
                    tempInterceptors.add(globalChannelInterceptorWrapper);
                }
            }
            Collections.sort(tempInterceptors, comparator);
            if (!tempInterceptors.isEmpty()) {
                for (int i = tempInterceptors.size() - 1; i >= 0; i--) {
                    interceptors.add(0, tempInterceptors.get(i).getChannelInterceptor());
                }
            }
        } else if (logger.isDebugEnabled()) {
            logger.debug("Global Channel interceptors will not be applied to Channel: " + beanName);
        }
    }

    @SuppressWarnings("unchecked")
    private List<ChannelInterceptor> getExistingInterceptors(MessageChannel channel) {
        try {
            MessageChannel targetChannel = channel;
            if (AopUtils.isAopProxy(channel)) {
                Object target = ((Advised) channel).getTargetSource().getTarget();
                if (target instanceof MessageChannel) {
                    targetChannel = (MessageChannel) target;
                }
            }
            DirectFieldAccessor channelAccessor = new DirectFieldAccessor(targetChannel);
            Object interceptorListWrapper = channelAccessor.getPropertyValue("interceptors");
            if (interceptorListWrapper != null) {
                return (List<ChannelInterceptor>) new DirectFieldAccessor(interceptorListWrapper)
                        .getPropertyValue("interceptors");
            }
        } catch (NotReadablePropertyException e) {
            // Channel doesn't support interceptors - null return logged by caller
        } catch (Exception e) {
            // interceptors not supported, will return null
            if (logger.isDebugEnabled() && channel != null) {
                logger.debug("interceptors not supported by channel '" + channel + "'", e);
            }
        }
        return null;
    }

}