ognl.ListPropertyAccessor Maven / Gradle / Ivy

Go to download
//--------------------------------------------------------------------------
//	Copyright (c) 1998-2004, Drew Davidson and Luke Blanshard
//  All rights reserved.
//
//	Redistribution and use in source and binary forms, with or without
//  modification, are permitted provided that the following conditions are
//  met:
//
//	Redistributions of source code must retain the above copyright notice,
//  this list of conditions and the following disclaimer.
//	Redistributions in binary form must reproduce the above copyright
//  notice, this list of conditions and the following disclaimer in the
//  documentation and/or other materials provided with the distribution.
//	Neither the name of the Drew Davidson nor the names of its contributors
//  may be used to endorse or promote products derived from this software
//  without specific prior written permission.
//
//	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
//  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
//  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
//  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
//  COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
//  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
//  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
//  OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
//  AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
//  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
//  THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
//  DAMAGE.
//--------------------------------------------------------------------------
package ognl;

import java.util.*;

/**
 * Implementation of PropertyAccessor that uses numbers and dynamic subscripts as
 * properties to index into Lists.
 * @author Luke Blanshard ([email protected])
 * @author Drew Davidson ([email protected])
 */
public class ListPropertyAccessor extends ObjectPropertyAccessor
    implements PropertyAccessor // This is here to make javadoc show this class as an implementor
{
    public Object getProperty( Map context, Object target, Object name ) throws OgnlException
    {
        List    list = (List)target;

        if ( name instanceof String ) {
            Object      result;

            if (name.equals("size")) {
                result = new Integer(list.size());
            } else {
                if (name.equals("iterator")) {
                    result = list.iterator();
                } else {
                    if (name.equals("isEmpty")) {
                        result = list.isEmpty() ? Boolean.TRUE : Boolean.FALSE;
                    } else {
                        result = super.getProperty( context, target, name );
                    }
                }
            }
            return result;
        }

        if ( name instanceof Number )
            return list.get( ((Number)name).intValue() );

        if ( name instanceof DynamicSubscript )
          {
            int len = list.size();
            switch ( ((DynamicSubscript)name).getFlag() )
              {
                case DynamicSubscript.FIRST:    return len > 0? list.get(0) : null;
                case DynamicSubscript.MID:      return len > 0? list.get(len/2) : null;
                case DynamicSubscript.LAST:     return len > 0? list.get(len-1) : null;
                case DynamicSubscript.ALL:      return new ArrayList(list);
              }
          }

        throw new NoSuchPropertyException( target, name );
    }

    public void setProperty( Map context, Object target, Object name, Object value ) throws OgnlException
    {
        if ( name instanceof String )
          {
            super.setProperty( context, target, name, value );
            return;
          }

        List list = (List)target;

        if ( name instanceof Number )
          {
            list.set( ((Number)name).intValue(), value );
            return;
          }

        if ( name instanceof DynamicSubscript )
          {
            int len = list.size();
            switch ( ((DynamicSubscript)name).getFlag() )
              {
                case DynamicSubscript.FIRST:    if ( len > 0 ) list.set(0,value);       return;
                case DynamicSubscript.MID:      if ( len > 0 ) list.set(len/2,value);   return;
                case DynamicSubscript.LAST:     if ( len > 0 ) list.set(len-1,value);   return;
                case DynamicSubscript.ALL:
                  {
                    if ( !(value instanceof Collection) )
                        throw new OgnlException( "Value must be a collection" );
                    list.clear();
                    list.addAll( (Collection)value );
                    return;
                  }
              }
          }

        throw new NoSuchPropertyException( target, name );
    }
}