ejbmethodinvoker.java

Java/J2EE框架Jdon-Framework系统的Sample

/**
 * Copyright 2005 Jdon.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.jdon.bussinessproxy.method;

import com.jdon.bussinessproxy.meta.EJBTargetMetaDef;
import com.jdon.bussinessproxy.MethodInvoker;
import com.jdon.bussinessproxy.TargetService;
import com.jdon.bussinessproxy.cache.ComponentCacheVisitor;

import com.jdon.util.Debug;

import java.lang.reflect.Method;
import com.jdon.bussinessproxy.TargetMetaDef;
import com.jdon.bussinessproxy.MyComponentProps;
import com.jdon.controller.ContainerWrapper;
import com.jdon.bussinessproxy.cache.VisitableNames;
import java.rmi.*;
import javax.rmi.PortableRemoteObject;
import javax.ejb.*;
import com.jdon.bussinessproxy.meta.*;

/**
 * 动态代理后真正的执行者
 *
 * 使用ComponentManager(HttpSession)作为EJB session bean的缓冲
 * ComponentManager还缓存了ProxyMethodInvocation.java
 *
 * <p>Copyright: Jdon.com Copyright (c) 2003</p>
 * <p></p>
 * @author banq
 * @version 1.0
 */
public class EJBMethodInvoker implements MethodInvoker {
  private final static String module = EJBMethodInvoker.class.getName();
  private TargetService targetService;
  private ComponentCacheVisitor cm;

  public void setVisitor(ComponentCacheVisitor cm) {
    this.cm = cm;
  }


  /**
    public HttpSessionProxy() {
      backService = new EJBProxyHandler();
    }
   **/

  public EJBMethodInvoker(TargetService targetService) {
    this.targetService = targetService;
  }

  /**
   * 对后台targetMetaDef实现调用处理
   * @param EJBDefinition
   * @param m
   * @param args
   * @return Object
   */
  public Object handleInvoker(TargetMetaDef targetMetaDef) throws
      Throwable {
    EJBTargetMetaDef eJBMetaDef = null;
    if (targetMetaDef.isEJB()) {
      eJBMetaDef = (EJBTargetMetaDef) targetMetaDef;
    } else {
      Debug.logError(" targetMetaDef is not EJB,but you call it by EJB", module);
      return null;
    }
    Debug.logVerbose(" now handleInvoker for targetMetaDef " + targetMetaDef.toString(), module);
    Object targetObjRef = null;
    if (cm == null) { //如无targetObjRef的cache，直接获得home.create
      Debug.logVerbose(" NOTE: not active cache !!!!", module);
      targetObjRef = targetService.createObject(eJBMetaDef);
    } else {
      eJBMetaDef.setVisitableName(VisitableNames.EJBTARGETSERVICE_NAME);
      Debug.logVerbose(VisitableNames.EJBTARGETSERVICE_NAME + " in action", module);
      targetObjRef = cm.visit(eJBMetaDef);
    }
    MethodMetaArgs methodMetaArgs = targetMetaDef.getMethodMetaArgs();
    return ejbInvoker(methodMetaArgs, targetObjRef);
  }

  /**
   * 调用对应的EJB实行处理
   *
   * @param EJBDefinition
   * @param m
   * @param args
   * @return Object
   */
  private Object ejbInvoker(MethodMetaArgs methodMetaArgs, Object targetObjRef) throws
      Throwable {
    Object result = null;
    try {
      Method invokedMethod = methodMetaArgs.getMethod();
      if (invokedMethod == null) //如果方法为空，构建它
        invokedMethod = MethodConstructor.createMethod(targetObjRef,
            methodMetaArgs.getMethodName(),
            methodMetaArgs.getParamTypes());

      Object[] p_args = methodMetaArgs.getArgs();
      result = invokedMethod.invoke(targetObjRef, narrowArgs(p_args));
    } catch (Exception ex) {
      Debug.logError("handleInvoker error: " + ex, module);
      throw new Exception(ex);
    } catch (Throwable ex) {
      throw new Throwable(ex);
    }
    return result;
  }

  /**
    * 如果参数中有remote EJB，需要从远程序列化过来这些参数
    *
    */
   public Object[] narrowArgs(Object[] p_args) {
     if (p_args == null)
       return null;
     int length = p_args.length;
     Object[] result = new Object[length];
     for (int i = 0; i < length; i++) {
       if (p_args[i] instanceof Remote)
         result[i] = PortableRemoteObject.narrow(p_args[i], EJBObject.class);
       else
         result[i] = p_args[i];
     }
     return result;
   }


}