1.责任链+命令模式（去掉事物责任Interceptor）

AbstractCommandInterceptor和Command

/* 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.activiti.engine.impl.interceptor;

/**
 * @author Tom Baeyens
 */
public interface Command <T> {

  T execute(CommandContext commandContext);

}

2.StartProcessInstanceCmd（跑流程的时候先读process实例的缓存）