/*
 * Copyright 2002,2004 The Apache Software Foundation.
 * 
 * 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 org.apache.commons.jexl.parser;

import org.apache.commons.jexl.JexlContext;
import org.apache.commons.jexl.util.Coercion;

/**
 *  LT : a < b
 *
 *  Follows A.3.6.1 of the JSTL 1.0 specification
 *
 *  @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
 *  @author <a href="mailto:proyal@apache.org">Peter Royal</a>
 *  @version $Id: ASTLTNode.java,v 1.5 2004/02/28 13:45:20 yoavs Exp $
 */
public class ASTLTNode extends SimpleNode
{
    public ASTLTNode(int id)
    {
        super(id);
    }

    public ASTLTNode(Parser p, int id)
    {
        super(p, id);
    }

    /** Accept the visitor. **/
    public Object jjtAccept(ParserVisitor visitor, Object data)
    {
        return visitor.visit(this, data);
    }

    public Object value(JexlContext jc)
        throws Exception
    {
        /*
         * now get the values
         */

        Object left = ( (SimpleNode) jjtGetChild(0)).value(jc);
        Object right = ( (SimpleNode) jjtGetChild(1)).value(jc);

        if( ( left == right ) || ( left == null ) || ( right == null ) )
        {
            return Boolean.FALSE;
        }
        else if( Coercion.isFloatingPoint( left ) || Coercion.isFloatingPoint( right ) )
        {
            double leftDouble = Coercion.coerceDouble( left ).doubleValue();
            double rightDouble = Coercion.coerceDouble( right ).doubleValue();

            return leftDouble < rightDouble
                ? Boolean.TRUE
                : Boolean.FALSE;
        }
        else if( Coercion.isNumberable( left ) || Coercion.isNumberable( right ) )
        {
            long leftLong = Coercion.coerceLong( left ).longValue();
            long rightLong = Coercion.coerceLong( right ).longValue();

            return leftLong < rightLong
                ? Boolean.TRUE
                : Boolean.FALSE;
        }
        else if( left instanceof String || right instanceof String )
        {
            String leftString = left.toString();
            String rightString = right.toString();

            return leftString.compareTo( rightString ) < 0
                ? Boolean.TRUE
                : Boolean.FALSE;
        }
        else if( left instanceof Comparable )
        {
            return ( (Comparable)left ).compareTo( right ) < 0
                ? Boolean.TRUE
                : Boolean.FALSE;
        }
        else if( right instanceof Comparable )
        {
            return ( (Comparable)right ).compareTo( left ) > 0
                ? Boolean.TRUE
                : Boolean.FALSE;
        }

        throw new Exception("Invalid comparison : LT ");
    }
}