Design Pattern series-strategy

I. Class Diagram

 

Ii. Intention

Define a seriesAlgorithm,Encapsulate them one by one,And make them replaceable. This mode allows algorithms to change independently of customers who use it.

Iii. Applicability

A) Many related classes only have different behaviors."Policy"Provides a method to configure a class with one of multiple actions.

B) use different variants of an algorithm. For example, you may define different spaces/Time-weighed algorithm. When these variants are implemented as class layers of an algorithm[H o 8 7],You can use the policy mode.

C) algorithms use data that customers should not know. Policy modes can be used to avoid exposing complex algorithm-related data structures.

D) A class defines multiple behaviors.,These actions appear in the form of multiple condition statements in the operations of this class. Move related condition branches to their respectiveS t r a t e g yClass to replace these conditional statements.

Iv. Instances

Zhuge Liang's tips:

Article 1: Let Zhao Yun and his entourage visit Qiao Guoluo first. Qiao Guo is always the ghost of Zhou Yu and Sun ce. He has a certain prestige in Dongwu and has a good relationship with Wu Guotai. When I visited Qiao guoyi, I could tell Wu Guotai about Sun Liu's marriage (Wu Guotai did not know before), and Sun Quan zhou Yu was passive. Secondly, let him speak out in front of Wu Guotai to increase the possibility of Sun Liu's marriage.

Article 2: swindling Cao to report the revenge of Chibi, raising troops to the south and sending Liu Bei back to Jingzhou. Liu Bei spent a whole day in Dongwu, so he was happy. This is the design of Zhou Yu to make Liu Bei have fun.

Article 3: Use Mrs sun to block the pursuit of troops. Sun shangxiang is also the owner of Dongwu County. In her words, Dongwu's generals still have to pay attention to the volume of traffic.

 Package Explore. Strategy;

 Public   Interface Strategy {
 Public   Void Perform ();
}

 Package Explore. Strategy;

 Public   Class Context {
Private Strategy strategy;

 Public Context (strategy Strategy ){
 This . Strategy = strategy;
}

 Public   Void Setstrategy (Strategy s ){
 This . Strategy = s;
}

 Public   Void Perform (){
 This . Strategy. Perform ();
}
}

 Package Explore. Strategy;

 Public   Class Thefirststrategy Implements Strategy {

@ Override
 Public   Void Perform (){
System. Out. println ("Let Zhao Yun and his entourage visit Qiao Guoluo first. ");
}

}

 Package Explore. Strategy;

 Public   Class Thesecondstrategy Implements Strategy {
@ Override
 Public   Void Perform (){
System. Out. println. ");
}

}

 Package Explore. Strategy;

 Public   Class ThethirdstrategyImplements Strategy {
@ Override
 Public   Void Perform (){
System. Out. println ("use Mrs sun to guard the army. ");
}

}

 Package Explore. Strategy;

 Public   Class Zhaoyun {
 Public   Static   Void Main (string [] ARGs ){
 //  Article 1: Let Zhao Yun and his entourage visit Qiao Guoluo first.  
 Strategy first = New Thefirststrategy ();
 //  Article 2: swindling Cao to report the revenge of Chibi, raising troops to the south and sending Liu Bei back to Jingzhou.  
 Strategy Second = New Thesecondstrategy ();
 //  Article 3: Use Mrs sun to block the pursuit of troops.  
 Strategy third = New Thethirdstrategy ();

Context c = New Context (first );
C. Perform ();
C. setstrategy (second );
C. Perform ();
C. setstrategy (third );
C. Perform ();
}
}

5. StrategyMode in the comparator (Comparator).

 

 //  Comparator  
  Public  Interface Comparator <t> {
 Int Compare (T O1, t O2 );
......

 //  Custom comparison algorithm  
  Public   Interface Comparable <t> {
 Public   Int Compareto (t o );

 //  Integer-defined comparison algorithm  
 Public   Final   Class Integer Extends Number Implements Comparable <integer> {
 Public   Int Compareto (integer anotherinteger ){
 Int Thisval = This . Value;
 Int Anotherval = anotherinteger. value;
 Return (Thisval <anotherval? -1: (thisval = anotherval? 0: 1 ));
}
......

 //  Comparison algorithms defined in the string class  
      Public   Int Compareto (string anotherstring ){
 Int Len1 = count;
 Int Len2 = anotherstring. count;
 Int N = math. Min (len1, len2 );
 Char V1 [] = value;
Char V2 [] = anotherstring. value;
 Int I = offset;
 Int J = anotherstring. offset;

 If (I = J ){
 Int K = I;
 Int Lim = N + I;
 While (K <Lim ){
 Char C1 = V1 [k];
 Char C2 = v2 [k];
 If (C1! = C2 ){
 Return C1-C2;
}
K ++;
}
} Else {
 While (N --! = 0 ){
 Char C1 = V1 [I ++];
 Char C2 = v2 [J ++];
 If (C1! = C2 ){
 Return C1-C2;
}
}
}
 Return Len1-len2;
}

 

When we compare two objects, we only need to call one compare ()Method:

 
IntCMP = comparator. Compare (obj1, obj2 );