subtract.java

来自「OpenJMS是一个开源的Java Message Service API 1.」· Java 代码 · 共 80 行

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package org.exolab.jms.selector;


/**
 * This class implements a '-' expression.
 *
 * @version     $Revision: 1.1 $ $Date: 2004/11/26 01:50:44 $
 * @author      <a href="mailto:[e-mail]">Tim Anderson</a>
 * @see         Expression
 * @see         MathOperator
 * @see         SNumber
 */
class Subtract extends MathOperator {

    /**
     * Construct a new <code>Subtract</code> operator
     *
     * @param lhs the left hand side of the expression
     * @param rhs the right hand side of the expression
     */
    public Subtract(final Expression lhs, final Expression rhs) {
        super("-", lhs, rhs);
    }

    /**
     * Evaluate the expression
     *
     * @param lhs the left hand side of the expression
     * @param rhs the right hand side of the expression
     * @return the value of <code>lhs - rhs</code>
     */
    protected final SNumber evaluate(final SNumber lhs, final SNumber rhs) {
        return lhs.subtract(rhs);
    }

} //-- Subtract