Application: gvSIG desktop

package com.hardcode.gdbms.engine.instruction;

import com.hardcode.gdbms.engine.data.DriverException;

import com.hardcode.gdbms.engine.values.Value;

/**

 * Adaptador

 *

 * @author Fernando Gonz?lez Cort?s

 */

public abstract class AbstractExpression extends Adapter implements Expression {

    protected boolean literal;

    private Value value;

    /**

     * @see com.hardcode.gdbms.engine.instruction.Expression#evaluateExpression(long)

     */

    public Value evaluateExpression(long row)

        throws SemanticException, DriverException {

        if (!isLiteral()) {

            return evaluate(row);

        } else {

            if (value == null) {

                return (value = evaluate(row));

            } else {

                return value;

            }

        }

    }

}