Java开发中的23种设计模式详解----解释器模式（Interpreter）

public interface  Expression
{
public int interpret(Context context);
}

public class Context
{
private int num1;
private int num2;

public Context(int num1, int num2)
{
super();
this.num1 = num1;
this.num2 = num2;
}

public int getNum1()
{
return num1;
}

public void setNum1(int num1)
{
this.num1 = num1;
}

public int getNum2()
{
return num2;
}

public void setNum2(int num2)
{
this.num2 = num2;
}

}

public class Minus implements Expression
{

@Override
public int interpret(Context context) {
return context.getNum1()-context.getNum2();
}
}

public class Plus implements Expression
{

@Override
public int interpret(Context context)
{
return context.getNum1()+context.getNum2();
}
}

/**
* 本就这样，解释器模式用来做各种各样的解释器，如正则表达式等的解释器等等！
* @author xiaodong
*
*/
public class Test
{
public static void main(String[] args)
{

// 计算9+2-8的值
int result = new Minus().interpret((new Context(new Plus().interpret(new Context(9, 2)), 8)));
System.out.println(result);
}
}