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JavaEE 1.6 API for Resin Java Application Server
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/*
 * Copyright (c) 1998-2018 Caucho Technology -- all rights reserved
 *
 * This file is part of Resin(R) Open Source
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Resin Open Source is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Resin Open Source 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, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Resin Open Source; if not, write to the
 *
 *   Free Software Foundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Scott Ferguson
 */

package javax.el;

import java.beans.FeatureDescriptor;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.Map;
import java.util.logging.Logger;

/**
 * Resolves properties based on maps.
 */
public class MapELResolver extends ELResolver {
  private final static Logger log
    = Logger.getLogger(MapELResolver.class.getName());
  
  private final boolean _isReadOnly;
  
  public MapELResolver()
  {
    _isReadOnly = false;
  }
  
  public MapELResolver(boolean isReadOnly)
  {
    _isReadOnly = isReadOnly;
  }

  @Override
  public Class getCommonPropertyType(ELContext context, Object base)
  {
    if (base instanceof Map) {
      context.setPropertyResolved(true);
      
      return Object.class;
    }
    else
      return null;
  }

  @Override
  public Iterator getFeatureDescriptors(ELContext context,
                                                           Object base)
  {
    if (base instanceof Map) {
      context.setPropertyResolved(true);

      ArrayList keys = new ArrayList();

      for (Object key : ((Map) base).keySet()) {
        String name = String.valueOf(key);

        FeatureDescriptor desc = new FeatureDescriptor();
        desc.setName(name);
        desc.setDisplayName(name);
        desc.setShortDescription("");
        desc.setExpert(false);
        desc.setHidden(false);
        desc.setPreferred(true);

        if (key == null)
          desc.setValue(ELResolver.TYPE, null);
        else
          desc.setValue(ELResolver.TYPE, key.getClass());

        desc.setValue(ELResolver.RESOLVABLE_AT_DESIGN_TIME, Boolean.TRUE);

        keys.add(desc);
      }

      return keys.iterator();
    }
    else {
      return null;
    }
  }

  @Override
  public Class getType(ELContext context,
                          Object base,
                          Object property)
  {
    if (context == null)
      throw new NullPointerException();
    
    if (base instanceof Map) {
      context.setPropertyResolved(true);
      
      return Object.class;
    }
    else
      return null;
  }

  @Override
  public Object getValue(ELContext context,
                         Object base,
                         Object property)
  {
    if (base instanceof Map && property != null) {
      Map map = (Map) base;
      
      context.setPropertyResolved(true);

      return map.get(property);
    }
    else {
      return null;
    }
  }

  @Override
  public boolean isReadOnly(ELContext context,
                            Object base,
                            Object property)
  {
    if (base instanceof Map) {
      context.setPropertyResolved(true);
      
      return _isReadOnly;
    }
    else
      return true;
  }

  @Override
  public void setValue(ELContext context,
                       Object base,
                       Object property,
                       Object value)
  {
    if (_isReadOnly)
      throw new PropertyNotWritableException("resolver is readonly");

    if (base instanceof Map && property != null) {
      Map map = (Map) base;
      
      context.setPropertyResolved(true);
      try {
        map.put(property, value);
      } catch (UnsupportedOperationException e) {
        throw new PropertyNotWritableException("map "
          + base
          + " of type "
          + map.getClass().getName()
          + " is umodifiable");
      }
    }
  }
}