modeldispaction.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.strutsutil;

import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionError;
import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.jdon.util.Debug;

import com.jdon.controller.model.Model;
import com.jdon.model.ModelHandler;
import com.jdon.model.ModelKey;
import org.apache.struts.config.ModuleConfig;
import org.apache.struts.util.RequestUtils;
import com.jdon.strutsutil.util.CreateViewPage;
import com.jdon.model.ModelManager;
import com.jdon.strutsutil.util.EditeViewPage;
import com.jdon.model.ModelManagerRegistry;
import javax.servlet.ServletContext;
import com.jdon.controller.ContainerClient;

/**
 * 专门显示Model类。
 *
 * 为安全起见，单独设立一个类。同时加入缓存机制。
 * request的nocache参数表示失效缓存机制。
 * modelDispAction.do?nocache
 *
 * <p>Copyright: Jdon.com Copyright (c) 2003</p>
 * <p></p>
 * @author banq
 * @version 1.0
 */
public class ModelDispAction extends ModelViewAction {

  private final static String module = ModelDispAction.class.getName();
  private ContainerClient containerClient = new ContainerClient();

  public ActionForward execute(ActionMapping actionMapping,
                               ActionForm actionForm,
                               HttpServletRequest request,
                               HttpServletResponse response) throws
      Exception {

    if (modelManager == null) {
      ServletContext sc = this.getServlet().getServletContext();
      modelManager = (ModelManager) containerClient.getPOJOService(
          ModelManagerRegistry.MM_NAME, sc);
      createViewPage = new CreateViewPage(modelManager);
      editeViewPage = new EditeViewPage(modelManager);
    }

    ModuleConfig moduleConfig = RequestUtils.getModuleConfig(request,
        getServlet().getServletContext());
    Model model = this.editeViewPage.getModelForEdit(actionMapping, actionForm,
        request, moduleConfig);

    if (model == null) { //如果查询失败，显示出错信息
      ActionErrors errors = new ActionErrors();
      Debug.logError("id.notfound in database", module);
      ActionError error = new ActionError("id.notfound");
      errors.add(ActionErrors.GLOBAL_ERROR, error);
      saveErrors(request, errors);
      return actionMapping.findForward(FormBeanUtil.FORWARD_FAILURE_NAME);
    } else {
      return actionMapping.findForward(FormBeanUtil.FORWARD_SUCCESS_NAME);
    }

  }

  /**
   * 首先查询缓存，然后从后台获取已经存在的Model数据
   * @param actionMapping
   * @param request
   * @param modelHandler
   * @return
   * @throws java.lang.Exception
   */
  private Model fetchModel(ActionMapping actionMapping,
                           HttpServletRequest request,
                           ModelHandler modelHandler) throws Exception {

    String paramKeyValue = this.editeViewPage.getParamKeyValue(actionMapping,
        request, modelHandler);
    if (paramKeyValue == null) {
      Debug.logVerbose(
          "  the keyValue is null, please finish it in findModelByKey method",
          module);
    }
    String nocache = request.getParameter("nocache");

    String formName = actionMapping.getAttribute();

    Model model = null;
    if (nocache != null) {
      model = modelHandler.findModelByKey(paramKeyValue, request);
    } else {
      //特别是 先从缓存获得。
      ModelKey modelKey = new ModelKey(paramKeyValue, formName);
      model = modelManager.getCache(modelKey);
      if (model == null) {
        model = modelHandler.findModelByKey(paramKeyValue, request);
        if ( (model != null) && (model.isCacheble())) {
          modelManager.addCache(modelKey, model);
        }
      }
    }

    return model;
  }

}