| gvSIG desktop 1

/*

 *    GeoTools - OpenSource mapping toolkit

 *    http://geotools.org

 *    (C) 2006, GeoTools Project Managment Committee (PMC)

 *    

 *    This library 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;

 *    version 2.1 of the License.

 *

 *    This library 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.

 */

package org.gvsig.data.vectorial.filter;

import org.opengis.filter.expression.Expression;

import org.opengis.filter.expression.ExpressionVisitor;

import org.opengis.filter.expression.Subtract;

/**

 * Implementation of Subtract expression.

 * 

 * @author Justin Deoliveira, The Open Planning Project, jdeolive@openplans.org

 *

 */

public class SubtractImpl implements Subtract {

        Expression exp1;

        Expression exp2;

        public SubtractImpl(Expression expr1, Expression expr2) {

                exp1=expr1;

                exp2=expr2;

        }

        public Object evaluate(Object feature) {

                double leftDouble = FilterUtils.number( getExpression1().evaluate(feature) );

                double rightDouble = FilterUtils.number( getExpression2().evaluate(feature) );

                return new Double(leftDouble - rightDouble);

    }

        public Object accept(ExpressionVisitor visitor, Object extraData) {

                return visitor.visit(this,extraData);

        }

        /**

     * Compares this expression to the specified object. Returns true if the 

     *

     * @param obj - the object to compare this expression against.

     *

     * @return true if specified object is equal to this expression; false

     *         otherwise.

     */

    public boolean equals(Object obj) {

            if (obj instanceof SubtractImpl) {

            SubtractImpl other = (SubtractImpl) obj;

            return exp1.equals(other.exp1)

                && exp2.equals(other.exp2);

        } else {

            return false;

        }

    }

    public String toString() {

            return "(" + getExpression1().toString() + "-" + getExpression2().toString()+ ")";

    }

        /**

         * We are not using context 

         */

        public Object evaluate(Object arg0, Class arg1) {

                return evaluate(arg0);

        }

        public Expression getExpression1() {

                return exp1;

        }

        public Expression getExpression2() {

                return exp2;

        }

}