Strategic mode (strategy pattern) detailed

Policy pattern: Defines the algorithm family, encapsulates each other, so that they can be replaced each other, this pattern makes the change of the algorithm independent of the client who uses the algorithm.

The subclass family of the parent class needs to extend the new function frequently, in order to use the parent class to add the subclass more flexibly, and to write the behavior of the parent class as an interface (interface);

Use the Set () method to reset the behavior of the interface. Methods that provide invocation of the behavior (such as perform) need to invoke the intrinsic method of the Interface (interface) (Fly & Quack).

Code:

Package strategy;  
      
Public abstract class Duck {//abstract class  
    Flybehavior Flybehavior;  
    Quackbehavior Quackbehavior;  
          
    Public Duck () {//constructor  
    } public  
          
    abstract void display ();//abstract function public  
          
    void Performfly () {  
        Flybehavior.fly ();  
    }  
          
    public void Performquack () {  
        quackbehavior.quack ();  
    }  
          
    public void Swim () {  
        System.out.println ("All ducks float, even decoys!");  
    }  
          
    public void Setflybehavior (Flybehavior fb) {  
        flybehavior = fb;  
    }  
          
    public void Setquackbehavior (Quackbehavior qb) {  
        quackbehavior = QB;  
    }  
}

Flybehavior and Quackbehavior are two interfaces (interface), containing methods fly () and quack ();

Methods of inheriting interfaces must use the methods of Fly () and quack ();

Code:

/** 
 * @time 2014.5.22
/package strategy;  
      
/** 
 * @author C.l.wang 
 * 
 *
/public interface Flybehavior {public  
    void Fly ();  
}

/** 
 * @time 2014.5.22
/package strategy;  
      
/** 
 * @author C.l.wang 
 * 
 *
/public interface Quackbehavior {public  
    void quack ();  
}

The implementation of the interface.

This column more highlights: http://www.bianceng.cnhttp://www.bianceng.cn/Programming/project/

Code:

/** 
 * @time 2014.5.22
/package strategy;  
      
/** 
 * @author C.l.wang 
 * 
 *
/public class Flynoway implements Flybehavior {* *  
      
    (Non-javadoc) c32/>* @see Strategy. Flybehavior#fly () 
     *
    /@Override public
    void Fly () {  
        //TODO auto-generated stub  
        System.out.println ("I can ' t fly!");  
    }  
      

/** 
 * * * * * *
package strategy;  
      
/** 
 * @author Administrator 
 * * * 
 /Public
class Flyrocketpowerd implements Flybehavior {  
      
    /* ( Non-javadoc) 
     * @see strategy. Flybehavior#fly () 
     *
    /@Override public
    void Fly () {  
        //TODO auto-generated stub  
        System.out.println ("I ' m flying with a rocket!");  
    }  
      

/** 
 * * * * * *
package strategy;  
      
/** 
 * @author Administrator 
 * * * 
 /Public
class Flyrocketpowerd implements Flybehavior {  
      
    /* ( Non-javadoc) 
     * @see strategy. Flybehavior#fly () 
     *
    /@Override public
    void Fly () {  
        //TODO auto-generated stub  
        System.out.println ("I ' m flying with a rocket!");  
    }  
      

/** 
 * * * * * *
package strategy;  
      
/** 
 * @author Administrator 
 *
/public class Mutequack implements Quackbehavior {  
      
    /* (Non-javadoc ) 
     * @see strategy. Quackbehavior#quack () 
     *
    /@Override public
    void Quack () {  
        //TODO auto-generated stub  
        System.out.println ("<< silence >>");  
    }  
      

/** 
 * * * * * *
package strategy;  
      
/** 
 * @author Administrator 
 * * * 
 /Public
class Quack implements Quackbehavior {  
      
    /* ( Non-javadoc) 
     * @see strategy. Quackbehavior#quack () 
     *
    /@Override public
    void Quack () {  
        //TODO auto-generated stub  
        System.out.println ("quack!");  
    }  
      

/** 
 * * * * * *
package strategy;  
      
/** 
 * @author Administrator 
 * * * 
 /Public
class Squeak implements Quackbehavior {* *  
      
    (Non-javadoc) c10/>* @see Strategy. Quackbehavior#quack () 
     *
    /@Override public
    void Quack () {  
        //TODO auto-generated stub  
        System.out.println ("Squeak");  
    }  
      

Inherits the subclass of the parent class by specifying the type of the behavior used (that is, the implementation of the interface (interface)) and providing its own display () function;

Code:

/** 
 * * * * * *
package strategy;  
      
/** 
 * @author Administrator 
 *
/public class Mallardduck extends Duck {public  
      
    mallardduck () {  
        Quackbehavior = new Quack ();  
        Flybehavior = new Flywithwings ();  
    }  
          
    /* (Non-javadoc) 
     * @see strategy. Duck#display () 
     *
    /@Override public
    void display () {  
        //TODO auto-generated method stub  
        System.out.println ("I ' m a real mallard duck!");  
    }  
      

/** 
 * * * * * *
package strategy;  
      
/** 
 * @author Administrator 
 * * * 
 /Public
class Modelduck extends Duck {public  
      
    Modelduck () {  
        Flybehavior = new Flynoway ();  
        Quackbehavior = new Quack ();  
    }  
          
    /* (Non-javadoc) 
     * @see strategy. Duck#display () 
     *
    /@Override public
    void display () {  
        //TODO auto-generated method stub  
        System.out.println ("I ' m a model duck.");  
    }  
      

At execution time, you can change the behavior of the parent class by simply executing the method (perform) of each subclass, or using the set () method.

Code:

/** 
 * * * * * *
package strategy;  
      
/** 
 * @author Administrator 
 */public
class Miniducksimulator {  
      
    /** 
     * @param args 
     */< C12/>public static void Main (string[] args) {  
        //TODO auto-generated method stub  
        Duck = new Mallard ( );  
        Mallard.performquack ();  
        Mallard.performfly ();  
              
        Duck model = new Modelduck ();  
        Model.performfly ();  
        Model.performquack ();  
              
        Model.setflybehavior (New Flyrocketpowerd ());  
        Model.performfly ();  
    }  
      

Object-oriented principles:

1. Package change parts;

2. Multi-use combination, less inheritance;

3. For interface programming, not for implementation programming;