单例、工厂、适配器、装饰器

单例

单例分为懒汉式和饿汉式

public class Singleton {
    
    
    //饿汉加载
    //应用时才加载，节省内存
    private static Singleton instance;   
    private Singleton() {  
    }  
    public static Singleton getInstance(){  
        if (instance == null) {  
            synchronized (Singleton.class) {  
                if (instance == null) {  
                    instance = new Singleton();  
                }  
            }  
        }  
        return instance;  
    } 
    
    
    //饿汉加载 
    //浪费内存
//    private static Singleton singleton=new Singleton();
//    public static Singleton getInstance(){
//        return singleton;
//    }
    
    public void run(){
        System.out.println("hellowolrd");
    }
}

 

工厂模式：

 工厂方法、抽象工厂

package Factory;


//抽象工厂
public class AbstractMethod {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        
        //简单工厂
//        ICar car=Driver.createCar("Bike");
//        car.goWork();
        
        
        //抽象工厂
//        LowPersonFactory lowPersonFactory=new LowPersonFactory();
//        ICar car=lowPersonFactory.getCar();
//        IBreakfast breakfast=lowPersonFactory.getBreakfast();
//        car.goWork();
//        breakfast.getEat();
    }
}



//简单工厂
class Driver{
    public static ICar createCar(String car){
        ICar c=null;
        if("Bike".equalsIgnoreCase(car)){
            c=new Bike();
        }else{
            c=new Car();
        }
        return c;
    }
}


//抽象工厂
interface ICar{
    public void goWork();
}

class Bike implements ICar{

    @Override
    public void goWork() {
        // TODO Auto-generated method stub
        System.out.println("自行车上班");
    }    
}


class Car implements ICar{

    @Override
    public void goWork() {
        // TODO Auto-generated method stub
        System.out.println("汽车上班");
    }
}


interface IBreakfast{
    public void getEat();
}

class Bread implements IBreakfast{

    @Override
    public void getEat() {
        // TODO Auto-generated method stub
        System.out.println("吃面包");
    }
}


class Noodle implements IBreakfast{

    @Override
    public void getEat() {
        // TODO Auto-generated method stub
        System.out.println("吃面");
    }
}


interface IFactory{
    public ICar getCar();
    public IBreakfast getBreakfast();
}

class LowPersonFactory  implements IFactory{

    @Override
    public ICar getCar() {
        // TODO Auto-generated method stub
        return new Bike();
    }

    @Override
    public IBreakfast getBreakfast() {
        // TODO Auto-generated method stub
        return new Noodle();
    }
}

 适配器：

适配器分为类适配器、对象适配器

类适配

用继承实现添加新功能

package Factory;


//类适配器
public class Adapter extends Adaptee implements Target{

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Adapter adapter=new Adapter();
        adapter.sampleOperation2();
    }

    @Override
    public void sampleOperation2() {
        // TODO Auto-generated method stub
        sampleOperation1();
        System.out.println("额外的代码操作");
    }
    
}


class Adaptee {
    
    public void sampleOperation1(){
        System.out.println("Adaptee");
    }

}


interface Target {
    
    public void sampleOperation2(); 
    
}

对象适配器：

利用组合来添加新功能：

package Factory;

//对象适配器
public class Adapter extends Adaptee implements Target{

    private Adaptee adaptee;
    
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Adaptee adaptee=new Adaptee();
        Adapter adapter=new Adapter(adaptee);
        adapter.sampleOperation2();
    }
    
    

    public Adapter(Adaptee adaptee) {
        this.adaptee=adaptee;
        // TODO Auto-generated constructor stub
    }



    @Override
    public void sampleOperation2() {
        // TODO Auto-generated method stub
        adaptee.sampleOperation1();
        System.out.println("额外的代码");
    }
    
}


class Adaptee {
    
    public void sampleOperation1(){
        System.out.println("Adaptee");
    }

}


interface Target {
    
    public void sampleOperation2(); 
    
}

 

装饰器：

package Factory;

public class Wrapper {
    
    public static void main(String[] args){
         TheGreatestSage sage = new Monkey();
         TheGreatestSage bird = new Bird(sage);
         bird.move();
    }
     
}

interface TheGreatestSage {
    
    public void move();
}


class Monkey implements TheGreatestSage {

    @Override
    public void move() {
        //代码
        System.out.println("Monkey Move");
    }
}


class Change implements TheGreatestSage {
    
    private TheGreatestSage sage;
    
    public Change(TheGreatestSage sage){
        this.sage = sage;
    }
    @Override
    public void move() {
        // 代码
        sage.move();
    }
}


class Fish extends Change {
    
    public Fish(TheGreatestSage sage) {
        super(sage);
    }

    @Override
    public void move() {
        // 代码
        System.out.println("Fish Move");
    }
}


class Bird extends Change {
    
    public Bird(TheGreatestSage sage) {
        super(sage);
    }

    @Override
    public void move() {
        // 代码
        System.out.println("Bird Move");
    }
}