not.java

来自「《Java与模式》一书的源代码」· Java 代码 · 共 36 行

package com.javapatterns.interpreter;

public class Not extends Expression
{
    private Expression exp;

    public Not(Expression exp)
    {
        this.exp = exp;
    }

    public boolean interpret(Context ctx)
    {
        return !exp.interpret(ctx);
    }

    public boolean equals(Object o)
    {
        if (o != null && o instanceof Not)
        {
            return this.exp.equals(((Not)o).exp);
        }
        return false;
    }

    public int hashCode()
    {
        return (this.toString()).hashCode();
    }

    public String toString()
    {
        return " (Not " + exp.toString() + ")";
    }
}