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/*
 * Beangle, Agile Java/Scala Development Scaffold and Toolkit
 *
 * Copyright (c) 2005-2013, Beangle Software.
 *
 * Beangle is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Beangle is distributed in the hope that it will be useful.
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with Beangle.  If not, see .
 */
package org.beangle.struts2.freemarker;

import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Set;

import freemarker.core.CollectionAndSequence;
import freemarker.ext.beans.CollectionModel;
import freemarker.ext.beans.MapModel;
import freemarker.ext.util.ModelFactory;
import freemarker.template.*;

/**
 * BeangleObjectWrapper不同于StrutsBeanWrapper，他扩展了DefaultObjectWrapper。提供了

 * 1)缺省的对象包装

 * 2)可以在set等没有顺序的模型使用?seq_contains等方法
 * 3)恢复了在Map上的get方法(被DefaultObjectWrapper覆盖掉的)

 * 4)提供了map上的values方法(等同于StrutsBeanWrapper的功能)
 */
public class BeangleObjectWrapper extends DefaultObjectWrapper {
  private boolean altMapWrapper;

  public BeangleObjectWrapper(boolean altMapWrapper) {
    this.altMapWrapper = altMapWrapper;
  }

  /**
   * 特殊包装set和map
   */
  public TemplateModel wrap(Object obj) throws TemplateModelException {
    if (obj == null) { return super.wrap(null); }
    if (obj instanceof List) { return new CollectionModel((Collection) obj, this); }
    // 使得set等集合可以排序
    if (obj instanceof Collection) { return new SimpleSequence((Collection) obj, this); }
    if (obj instanceof Map) {
      if (altMapWrapper) {
        return new FriendlyMapModel((Map) obj, this);
      } else {
        return new MapModel((Map) obj, this);
      }
    }
    return super.wrap(obj);
  }

  // attempt to get the best of both the SimpleMapModel and the MapModel
  // of FM.
  @SuppressWarnings("rawtypes")
  protected ModelFactory getModelFactory(Class clazz) {
    if (altMapWrapper && Map.class.isAssignableFrom(clazz)) { return FriendlyMapModel.FACTORY; }
    return super.getModelFactory(clazz);
  }

  /**
   * Attempting to get the best of both worlds of FM's MapModel and
   * simplemapmodel, by reimplementing the isEmpty(), keySet() and values()
   * methods. ?keys and ?values built-ins are thus available, just as well as
   * plain Map methods.
   */
  private final static class FriendlyMapModel extends MapModel implements TemplateHashModelEx,
      TemplateMethodModelEx, AdapterTemplateModel {
    static final ModelFactory FACTORY = new ModelFactory() {
      public TemplateModel create(Object object, ObjectWrapper wrapper) {
        return new FriendlyMapModel((Map) object, (BeangleObjectWrapper) wrapper);
      }
    };

    public FriendlyMapModel(Map map, BeangleObjectWrapper wrapper) {
      super(map, wrapper);
    }

    // Struts2将父类的&& super.isEmpty()省去了，原因不知
    public boolean isEmpty() {
      return ((Map) object).isEmpty();
    }

    // 此处实现与MapModel不同，MapModel中复制了一个集合
    // 影响了?keySet,?size方法
    protected Set keySet() {
      return ((Map) object).keySet();
    }

    // add feature
    public TemplateCollectionModel values() {
      return new CollectionAndSequence(new SimpleSequence(((Map) object).values(), wrapper));
    }
  }
}