nats.client.spring.AnnotationConfigBeanPostProcessor.java Source code

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Here is the source code for nats.client.spring.AnnotationConfigBeanPostProcessor.java

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/*
 *   Copyright (c) 2012 Mike Heath.  All rights reserved.
 *
 *   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 nats.client.spring;

import nats.client.Message;
import nats.client.MessageHandler;
import nats.client.Nats;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanInitializationException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.core.annotation.AnnotationUtils;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

/**
 * @author Mike Heath <elcapo@gmail.com>
 */
public class AnnotationConfigBeanPostProcessor implements BeanPostProcessor {

    private final Nats nats;

    public AnnotationConfigBeanPostProcessor(Nats nats) {
        this.nats = nats;
    }

    @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();
        for (final Method method : clazz.getMethods()) {
            final Subscribe annotation = AnnotationUtils.findAnnotation(method, Subscribe.class);
            if (annotation != null) {
                final Class<?>[] parameterTypes = method.getParameterTypes();
                if (parameterTypes.length != 1 || !parameterTypes[0].equals(Message.class)) {
                    throw new BeanInitializationException(String.format(
                            "Method '%s' on bean with name '%s' must have a single parameter of type %s when using the @%s annotation.",
                            method.toGenericString(), beanName, Message.class.getName(),
                            Subscribe.class.getName()));
                }
                nats.subscribe(annotation.value()).addMessageHandler(new MessageHandler() {
                    @Override
                    public void onMessage(Message message) {
                        try {
                            method.invoke(bean, message);
                        } catch (IllegalAccessException e) {
                            throw new RuntimeException(e);
                        } catch (InvocationTargetException e) {
                            final Throwable targetException = e.getTargetException();
                            if (targetException instanceof RuntimeException) {
                                throw (RuntimeException) targetException;
                            }
                            throw new RuntimeException(targetException);
                        }
                    }
                });
            }
        }

        return bean;
    }
}