/*
 *    Geotoolkit - An Open Source Java GIS Toolkit
 *    http://www.geotoolkit.org
 *
 *    (C) 2002-2008, Open Source Geospatial Foundation (OSGeo)
 *    (C) 2009, Geomatys
 *
 *    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.geotoolkit.filter.binaryexpression;

import org.geotoolkit.util.StringUtilities;
import org.opengis.filter.expression.Add;
import org.opengis.filter.expression.Expression;
import org.opengis.filter.expression.ExpressionVisitor;

/**
 * Immutable "add" expression.
 *
 * @author Johann Sorel (Geomatys)
 * @module
 */
public class DefaultAdd extends AbstractBinaryExpression<Expression,Expression> implements Add{

    public DefaultAdd(final Expression left, final Expression right) {
        super(left,right);
    }

    /**
     * {@inheritDoc }
     */
    @Override
    public Object evaluate(final Object object) {
        final Double val1 = left.evaluate(object, Double.class);
        final Double val2 = right.evaluate(object, Double.class);

        if(val1 == null || val2 == null){
            final Object obj1 = left.evaluate(object);
            final Object obj2=  right.evaluate(object);
            return String.valueOf(obj1) + String.valueOf(obj2);
        }

        return val1 + val2;
    }

    /**
     * {@inheritDoc }
     */
    @Override
    public Object accept(final ExpressionVisitor visitor, final Object extraData) {
        return visitor.visit(this, extraData);
    }

    /**
     * {@inheritDoc }
     */
    @Override
    public String toString() {
        final StringBuilder sb = new StringBuilder("Add \n");
        sb.append(StringUtilities.toStringTree(left,right));
        return sb.toString();
    }

    /**
     * {@inheritDoc }
     */
    @Override
    public boolean equals(final Object obj) {
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        final AbstractBinaryExpression other = (AbstractBinaryExpression) obj;
        if (this.left != other.left && !this.left.equals(other.left)) {
            return false;
        }
        if (this.right != other.right && !this.right.equals(other.right)) {
            return false;
        }
        return true;
    }

    /**
     * {@inheritDoc }
     */
    @Override
    public int hashCode() {
        int hash = 5;
        hash = 53 * hash + this.left.hashCode() ;
        hash = 53 * hash + this.right.hashCode() ;
        return hash;
    }

}