content: /*
   * Copyright (C) 2010-2101 Alibaba Group Holding Limited.
   *
   * 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.alibaba.otter.shared.communication.core.impl;
  
  import java.lang.reflect.Method;
  
  import org.apache.commons.lang.StringUtils;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.springframework.util.ReflectionUtils;
  
  import com.alibaba.otter.shared.communication.core.CommunicationEndpoint;
  import com.alibaba.otter.shared.communication.core.CommunicationRegistry;
  import com.alibaba.otter.shared.communication.core.exception.CommunicationException;
  import com.alibaba.otter.shared.communication.core.model.Event;
  import com.alibaba.otter.shared.communication.core.model.heart.HeartEvent;
  
  /**
   * 默认的endpoint实现
   * 
   * @author jianghang 2011-9-9 下午07:01:49
   */
  public abstract class AbstractCommunicationEndpoint implements CommunicationEndpoint {
  
      // 需要禁止输出详细内容的事件
      private static final Logger logger         = LoggerFactory.getLogger(CommunicationEndpoint.class);
  
      private static final String DEFAULT_METHOD = "handleEvent";
  
      /**
       * 处理指定的事件
       */
      public Object acceptEvent(Event event) {
          if (event instanceof HeartEvent) {
              return event; // 针对心跳请求，返回一个随意结果
          }
  
          try {
              Object action = CommunicationRegistry.getAction(event.getType());
              if (action != null) {
  
                  // 通过反射获取方法并执行
                  String methodName = "on" + StringUtils.capitalize(event.getType().toString());
                  Method method = ReflectionUtils.findMethod(action.getClass(), methodName,
                                                             new Class[] { event.getClass() });
                  if (method == null) {
                      methodName = DEFAULT_METHOD; // 尝试一下默认方法
                      method = ReflectionUtils.findMethod(action.getClass(), methodName, new Class[] { event.getClass() });
  
                      if (method == null) { // 再尝试一下Event参数
                          method = ReflectionUtils.findMethod(action.getClass(), methodName, new Class[] { Event.class });
                      }
                  }
                  // 方法不为空就调用指定的方法,反之调用缺省的处理函数
                  if (method != null) {
                      try {
                          ReflectionUtils.makeAccessible(method);
                          return method.invoke(action, new Object[] { event });
                      } catch (Throwable e) {
                          throw new CommunicationException("method_invoke_error:" + methodName, e);
                      }
                  } else {
                      throw new CommunicationException("no_method_error for["
                                                       + StringUtils.capitalize(event.getType().toString())
                                                       + "] in Class[" + action.getClass().getName() + "]");
                  }
  
              }
  
              throw new CommunicationException("eventType_no_action", event.getType().name());
          } catch (RuntimeException e) {
              logger.error("endpoint_error", e);
              throw e;
          } catch (Exception e) {
              logger.error("endpoint_error", e);
              throw new CommunicationException(e);
          }
      }
  }
  