Design Pattern---interpreter mode

The usual scenarios for interpreter mode are calculators, or formulas.

That is to say, the symbol of interpretation satisfies the element of the formula, and the client side replaces the contents of each element.

 Package com.jayfulmath.designpattern.experssion; Import Java.util.HashMap;  Public Abstract class experssion {    // parse formulas and values where the key value in Var is the parameter in the formula, and the value is the specific number     Public Abstract int Interpreter (hashmap<string, integer> var);}

 Packagecom.jayfulmath.designpattern.experssion;ImportJava.util.HashMap; Public classVarexperssionextendsexperssion {PrivateString Key; @Override Public intInterpreter (Hashmap<string, integer>var) {System.out.println ("Varexperssion Interpreter key:" +key); returnVar.get (key); }     Publicvarexperssion (String key) {Super();  This. Key =key; }        }

 public  abstract  class  symbolexperssion     experssion {experssion left;    Experssion right;  public   Symbolexperssion (experssion        Left, experssion right) { super   ();          left;     this . Right =

 import   Java.util.HashMap;  public  class     Addexperssion extends   Symbolexperssion {  public   Addexperssion (Experssion left,            Experssion right) { super   (left, right); } @Override  public  int  in Terpreter (hashmap<string, Integer> Var) { return   .right.interpreter (Var); }    }

 Packagecom.jayfulmath.designpattern.experssion;ImportJava.util.HashMap; Public classSubexperssionextendssymbolexperssion { PublicSubexperssion (experssion left, experssion right) {Super(left, right); } @Override Public intInterpreter (Hashmap<string, integer>var) {        return Super. Left.interpreter (Var)-Super. Right.interpreter (Var); }}

Design Pattern---interpreter mode