andexp.java

23种设计模式的java实现 include vistor,proxy,bridge

/**
 *  A NonterminalExpression
 */
public class AndExp implements BooleanExp {
    private BooleanExp operand1;
    private BooleanExp operand2;
    
    public AndExp(BooleanExp oper1, BooleanExp oper2) {
        operand1 = oper1;
        operand2 = oper2;
    }

    public boolean Evaluate(Context c) {
        return operand1.Evaluate(c) &&
                    operand2.Evaluate(c);
    }

    public BooleanExp Copy() {
        return new AndExp(operand1.Copy(), operand2.Copy());
    }

    public BooleanExp Replace(String var, BooleanExp exp) {
        return new AndExp(
                    operand1.Replace(var, exp),
                    operand2.Replace(var, exp)
                    );
    }
}