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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.Iterator;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;

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

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

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

      return null;
    }
    else {
      return null;
    }
  }

  @Override
  public Class getType(ELContext context,
                          Object base,
                          Object property)
  {
    if (context == null)
      throw new NullPointerException();

    if (base instanceof List) {
      context.setPropertyResolved(true);

      int index = ArrayELResolver.getIndex(property);

      if (index < 0 || ((List) base).size() <= index)
        throw new PropertyNotFoundException("list index '" +
                                            index +
                                            "' is invalid");

      return Object.class;
    }
    else
      return null;
  }

  /**
   *
   * @param context
   * @param base
   * @param property
   * @return If the propertyResolved property of
     *     ELContext was set to true, then
     *     the value at the given index or null
     *     if the index was out of bounds. Otherwise, undefined.
   */
  @Override
  public Object getValue(ELContext context,
                         Object base,
                         Object property)
  {
    if (base instanceof List) {
      List list = (List) base;
      
      context.setPropertyResolved(true);

      int index = ArrayELResolver.getIndex(property);

      if (0 <= index && index < list.size())
        return list.get(index);
      else
        return null;
    }
    else {
      return null;
    }
  }

  @Override
  public boolean isReadOnly(ELContext context,
                            Object base,
                            Object property)
  {
    if (base instanceof List) {
      context.setPropertyResolved(true);

      int index = ArrayELResolver.getIndex(property);

      if (index < 0 || index >= ((List) base).size())
        throw new PropertyNotFoundException("list index '" +
                                            index +
                                            "' is invalid");
      return _isReadOnly;
    }
    else
      return false;
  }

  @Override
  public void setValue(ELContext context,
                       Object base,
                       Object property,
                       Object value)
  {
    if (base instanceof List) {
      List list = (List) base;

      context.setPropertyResolved(true);

      int index = ArrayELResolver.getIndex(property);

      if (_isReadOnly)
        throw new PropertyNotWritableException("resolver is read-only");

      if (index < 0 || list.size() < index)
        throw new PropertyNotFoundException("list index '" +
                                            index +
                                            "' is invalid");
      list.set(index, value);
    }
  }
}