editeviewpage.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.util;

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

import com.jdon.util.Debug;

import com.jdon.controller.model.Model;
import com.jdon.model.mapping.ModelMapping;
import com.jdon.model.ModelHandler;
import com.jdon.model.ModelForm;
import com.jdon.model.ModelManager;
import com.jdon.model.ModelKey;

import com.jdon.strutsutil.FormBeanUtil;
import org.apache.struts.config.ModuleConfig;


/**
 * 提供用于Model编辑页面的准备工作
 * 如获得已经存在的Model
 *
 * <p>Copyright: Jdon.com Copyright (c) 2003</p>
 * <p></p>
 * @author banq
 * @version 1.0
 */
public class EditeViewPage {
  private final static String module = EditeViewPage.class.getName();

  private ModelManager modelManager;
   public  EditeViewPage(ModelManager modelManager) {
     this.modelManager = modelManager;
   }

  /**
   * 为编辑或查询页面准备有数据的Model实例
   * 调用用户自己定义的ModelHandler并运行
   *
   * @param actionMapping ActionMapping
   * @param actionForm ActionForm
   * @param request HttpServletRequest
   * @param modelHandler ModelHandler
   * @throws Exception
   * @return Model
   */
  public Model getModelForEdit(ActionMapping actionMapping,
                                  ActionForm actionForm,
                                  HttpServletRequest request,
                                  ModuleConfig moduleConfig) throws Exception {
    Model model = null;
    ModelHandler modelHandler = null;
    try {
      String formName = FormBeanUtil.getFormName(actionMapping);
      modelHandler = modelManager.borrowtHandlerObject(formName);

      //1.生成新的ActionForm，保存在atrribute中
      ModelForm form = getModelForm(actionMapping,
                                    modelHandler,
                                    actionForm,
                                    request,
                                    moduleConfig);
      FormBeanUtil.saveActionForm(form, actionMapping, request);
      Debug.logVerbose(" got a ModelForm ... " , module);

      //设定为编辑调用 注：由调用者参数决定 由action值决定，如是view，则要在配置中配置view
      String action = request.getParameter("action");
      if (action != null)
        form.setAction(action);
      else
        Debug.logError(" action is null !", module);

      Debug.logVerbose(" prepare to fetch a Model from backend" , module);
      model = fetchModel(actionMapping, request, modelHandler);
      Debug.logVerbose(" got the Model data successfully..", module);
      if (model != null) //如果查询成功，数据对象拷贝
        modelHandler.modelCopyToForm(model, form);

      modelHandler.customizeForm(form, request);
    } catch (Exception ex) {
      Debug.logError("please check your ejb 、 model or form " + ex, module);
      throw new Exception("System error! please call system Admin." + ex);
    } finally {
      modelManager.returnHandlerObject(modelHandler); //返回modelhandler再用
    }
    return model;
  }

  private ModelForm getModelForm(ActionMapping actionMapping,
                                 ModelHandler modelHandler,
                                 ActionForm actionForm,
                                 HttpServletRequest request,
                                 ModuleConfig moduleConfig) throws Exception {
    Debug.logVerbose(" enter doCreate... ", module);
    ModelForm form = modelHandler.initForm(request);
    if (form == null)
      if (actionForm != null)
        form = (ModelForm) actionForm;
      else
        form = FormBeanUtil.createModelFormNow(actionMapping, actionForm, request,
                                               moduleConfig);
    return form;
  }


  /**
   * 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 = getParamKeyValue(actionMapping, request, modelHandler);
    if (paramKeyValue == null) {
      Debug.logVerbose("the keyValue is null, maybe is saved in session",  module);

    }

    String formName = actionMapping.getAttribute();
    Model model = null;
    try{
      //从数据库获取。
      model =  modelHandler.findModelByKey(paramKeyValue, request);
      if ( (model != null) && (model.isCacheble())) {
        ModelKey modelKey = new ModelKey(paramKeyValue, formName);
        modelManager.addCache(modelKey, model);
      }
    }catch(Exception ex){
      Debug.logError(" Your handler happens errors, try to catch them !" + ex, module);
      throw new Exception(ex);
    }

    return model;
  }

  /**
   * 获得参数key值
   * 例如：　
   * /admin/productAction.do?action=edit&productId=1721
   * 缺省:productId为product的modelmapping.xml中key定义值
   *
   * 对于如下调用：
   * /admin/productAction.do?action=edit&userId=16
   * userId不是modelmapping.xml中key定义值，则需要override本方法，
   *
   *
   * @param actionMapping
   * @param request
   * @return 参数key值
   * @throws java.lang.Exception
   */
  public String getParamKeyValue(ActionMapping actionMapping,
                                 HttpServletRequest request,
                                 ModelHandler modelHandler) throws
      Exception {

    //获得key的值
    ModelMapping modelMapping = modelHandler.getModelMapping();
    String keyName = modelMapping.getKeyName();
    Debug.logVerbose(" the keyName is  " + keyName , module);
    String keyValue = request.getParameter(keyName);
    Debug.logVerbose(" got the keyValue is  " + keyValue , module);

    return keyValue;
  }


}