com.excilys.spring.mom.annotation.MOMAnnotationProcessing.java Source code

Introduction

Here is the source code for com.excilys.spring.mom.annotation.MOMAnnotationProcessing.java

Source

/**
 * Copyright 2010-2011 eBusiness Information, Groupe Excilys (www.excilys.com)
 *
 * 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 com.excilys.spring.mom.annotation;

import java.lang.reflect.Method;
import java.net.SocketException;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.core.Ordered;
import org.springframework.stereotype.Component;
import org.springframework.util.ReflectionUtils;

import com.excilys.soja.client.exception.NotConnectedException;
import com.excilys.spring.mom.client.MOMClient;
import com.excilys.spring.mom.client.MOMMethodHandler;

/**
 * @author dvilleneuve
 * 
 */
@Component
public class MOMAnnotationProcessing implements BeanPostProcessor, Ordered {

    private static final Logger LOGGER = LoggerFactory.getLogger(MOMAnnotationProcessing.class);

    @Autowired
    private MOMClient momClient;

    @Autowired
    private ConfigurableApplicationContext applicationContext;

    @Override
    public int getOrder() {
        return LOWEST_PRECEDENCE;
    }

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

    @Override
    public Object postProcessAfterInitialization(final Object bean, String beanName) throws BeansException {
        final Class<?> clazz = bean.getClass();
        MOMController classAnnotation = clazz.getAnnotation(MOMController.class);

        // If the bean is annotated with @MOMController
        if (classAnnotation != null) {
            LOGGER.debug("Found @MOMController annotated class : {}", clazz);

            ReflectionUtils.doWithMethods(clazz, new ReflectionUtils.MethodCallback() {
                public void doWith(Method method) throws IllegalArgumentException, IllegalAccessException {
                    MOMMapping methodAnnotation = method.getAnnotation(MOMMapping.class);

                    // If the method is annotated with @MOMMapping
                    if (methodAnnotation != null) {
                        String topic = resolveProperty(methodAnnotation.topic());
                        MOMMappingConsum consum = methodAnnotation.consumes();

                        LOGGER.debug("Configuring @MOMMapping({}) method {}", consum, method);

                        try {
                            momClient.subscribe(topic, new MOMMethodHandler(method, bean, consum));
                        } catch (NotConnectedException e) {
                            LOGGER.error("Can't subscribe to topic {}", topic, e);
                        } catch (SocketException e) {
                            LOGGER.error("Can't subscribe to topic {}", topic, e);
                        }
                    }
                }
            });
        }

        return bean;
    }

    /**
     * Resolve the value parameter as a property formatted like <code>${my.property}</code>
     * 
     * @param value
     * @return
     */
    private String resolveProperty(String value) {
        if (applicationContext != null) {
            return applicationContext.getBeanFactory().resolveEmbeddedValue(value);
        }
        return value;
    }
}