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Java > Open Source Codes > org > jmock > examples > calculator > expression > BinaryOperator


1 /* Copyright (c) 2000-2004 jMock.org
2  */
3 package org.jmock.examples.calculator.expression;
4
5 import org.jmock.examples.calculator.CalculatorException;
6 import org.jmock.examples.calculator.Environment;
7 import org.jmock.examples.calculator.Expression;
8
9
10 public abstract class BinaryOperator implements Expression
11 {
12
13     private Expression left, right;
14
15     protected BinaryOperator( Expression left, Expression right ) {
16         this.left = left;
17         this.right = right;
18     }
19
20     public double evaluate( Environment environment )
21             throws CalculatorException {
22         return operator(left.evaluate(environment),
23                         right.evaluate(environment));
24     }
25
26     protected abstract double operator( double leftArg, double rightArg )
27             throws CalculatorException;
28 }
29
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