MethodRegistrar.java

/**
 * Copyright 2010-2016 Ralph Schaer <ralphschaer@gmail.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 ch.ralscha.extdirectspring.controller;

import java.lang.reflect.Method;
import java.util.Set;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationListener;
import org.springframework.context.event.ContextRefreshedEvent;
import org.springframework.core.MethodIntrospector;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.stereotype.Service;
import org.springframework.util.ClassUtils;
import org.springframework.util.ReflectionUtils.MethodFilter;
import org.springframework.util.StringUtils;

import ch.ralscha.extdirectspring.annotation.ExtDirectMethod;
import ch.ralscha.extdirectspring.util.MethodInfoCache;

/**
 * Spring application listener that listens for ContextRefreshedEvent events. If such an
 * event is received the listener will scan for ExtDirectMethod annotated methods in the
 * current ApplicationContext. Found methods will be cached in the {@link MethodInfoCache}
 * . The class also reports warnings and errors of misconfigured methods.
 */
@Service
public class MethodRegistrar
		implements ApplicationListener<ContextRefreshedEvent>, Ordered {

	private static final Log log = LogFactory.getLog(RouterController.class);

	private final MethodInfoCache methodInfoCache;

	@Autowired
	public MethodRegistrar(MethodInfoCache methodInfoCache) {
		this.methodInfoCache = methodInfoCache;
	}

	@Override
	public void onApplicationEvent(ContextRefreshedEvent event) {

		ApplicationContext context = (ApplicationContext) event.getSource();

		String[] beanNames = context.getBeanNamesForType(Object.class);

		for (String beanName : beanNames) {

			Class<?> handlerType = context.getType(beanName);
			final Class<?> userType = ClassUtils.getUserClass(handlerType);

			Set<Method> methods = MethodIntrospector.selectMethods(userType,
					new MethodFilter() {
						@Override
						public boolean matches(Method method) {
							return AnnotationUtils.findAnnotation(method,
									ExtDirectMethod.class) != null;
						}
					});

			for (Method method : methods) {
				ExtDirectMethod directMethodAnnotation = AnnotationUtils
						.findAnnotation(method, ExtDirectMethod.class);
				final String beanAndMethodName = beanName + "." + method.getName();
				if (directMethodAnnotation.value().isValid(beanAndMethodName, userType,
						method)) {
					this.methodInfoCache.put(beanName, handlerType, method,
							event.getApplicationContext());

					// /CLOVER:OFF
					if (log.isDebugEnabled()) {
						String info = "Register " + beanAndMethodName + "("
								+ directMethodAnnotation.value();
						if (StringUtils.hasText(directMethodAnnotation.group())) {
							info += ", " + directMethodAnnotation.group();
						}
						info += ")";
						log.debug(info);
					}
					// /CLOVER:ON
				}
			}

		}
	}

	@Override
	public int getOrder() {
		return Ordered.LOWEST_PRECEDENCE - 1000;
	}

}