Strategy Mode of design pattern

Policy Mode

policy mode : Refers to a specified object has a behavior, but in different scenarios, the behavior has a different implementation way. by implementing the different implementations independently, and allowing them to be replaced by each other , so that the different ways independent, for the user to choose.

Uml

The following is a simple arithmetic operation using the policy pattern:

 package   strategy;  /**    @author   WxH * @vertion 1.0  */ public  interface   Operator { int  Execute (int  num1,  num2); }

 package   strategy;  /**   * addition Operation *   @author   WxH * @vertion 1.0  */ public  class  Plus implements   operator{@Override  Span style= "color: #0000ff;" >public  int  Execute (int  Num1, Span style= "color: #0000ff;" >int   num2) { return  num1 + num2; }}

 Package strategy; /**  @author*/Publicclassimplements  Operator {    @Override      Public int Execute (intint  num2) {        return num1- num2;    }} 

 Packagestrategy;/*** Calculator *@authorWxH * @vertion 1.0*/ Public classCalculator {//Number 1    Private intNumber1; //Number 2    Private intnumber2; //operator    PrivateOperator Operator; //return operation result     Public intGetResult () {returnOperator.execute (Number1, number2); }     Public intGetNumber1 () {returnNumber1; }     Public voidSetNumber1 (intnumber1) {         This. Number1 =Number1; }     Public intGetNumber2 () {returnnumber2; }     Public voidSetNumber2 (intnumber2) {         This. number2 =number2; }     PublicOperator Getoperator () {returnoperator; }     Public voidsetoperator (Operator Operator) { This. operator =operator; }    }

 Package strategy;  Public class Test {        publicstaticvoid  main (string[] args) {                new Calculator ();         );          );         // set operator        New Plus ());        System.out.println (Cal.getresult ());}            }

Execution Result: 50

Policy mode + Template method used together

/*** Calculator *@authorWxH * @vertion 1.0*/ Public classCalculator {Private intNumber1; Private intnumber2;  Public intGetNumber1 () {returnNumber1; }     Public voidSetNumber1 (intnumber1) {         This. Number1 =Number1; }     Public intGetNumber2 () {returnnumber2; }     Public voidSetNumber2 (intnumber2) {         This. number2 =number2; }    }

/*** Template Method *@authorWxH * @vertion 1.0*/ Public Abstract classOperator {PrivateCalculator Cal;  PublicOperator (Calculator cal) { This. Cal =Cal; }        protected Abstract intExecuteintNUM1,intnum2);  Public intDoexecute () {return Execute (cal.getnumber1 (), Cal.getnumber2 ()); }    }

 /**   * addition Operation *   @author   WxH * @vertion 1.0  */ Span style= "color: #0000ff;" >public  class  Plus extends   operator{ public   Plus (Calculator cal) {     super   (CAL); } @Override  protected  int  Execute (int  num1, int   num2)    { return  num1 + num2; } }

 Public classTest01 { Public Static voidMain (string[] args) {Calculator cal=NewCalculator (); Cal.setnumber1 (30); Cal.setnumber2 (20); Plus P=NewPlus (CAL);//addition//minus m = new Minus (CAL);//SubtractionSystem.out.println (P.doexecute ()); }    }

Execution Result: 50

Strategy Mode of design pattern