决定开始写博客，为了能不断的学习，同时也方便回味学过的知识，万事开头难，先开始做起来！

package btp.oneP;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

//简单的工厂模式
public class RegisteredFactories {

    public static void main(String[] args) {
        for(int i=0;i<10;i++){
            System.out.println(Part.createRandom());
        }
    }

}

//抽象工厂 -> 可返回一个特定类型的对象实例
interface Factory<T>{T create();}

class Part{
    public String toString(){
        return this.getClass().getSimpleName();
    }
    //工厂注册写在基类的好处：可以用自身类型来存储
    static List<Factory<? extends Part>> partFactories = 
            new ArrayList<Factory<? extends Part>>();
    static{
        //工厂注册
        //工厂注册最好写在基类中，类型比较好处理
        partFactories.add(FuelFilter.factory());
        partFactories.add(AirlFilter.factory());
        partFactories.add(CabinAirlFilter.factory());
        partFactories.add(OilFilter.factory());
        partFactories.add(FanBelt.factory());
        partFactories.add(GeneratorBelt.factory());
        partFactories.add(PowerSteeringBelt.factory());
    }
    private static Random rand = new Random(47);
    public static Part createRandom(){
        int n = rand.nextInt(partFactories.size());
        return partFactories.get(n).create();
    }
    
}

class Filter extends Part{}

//每个类都能产生可以返回自身实例的工厂实例
class FuelFilter extends Filter{
    public static Factory<FuelFilter> factory(){
        return new Factory<FuelFilter>(){
            @Override
            public FuelFilter create() {
                // TODO Auto-generated method stub
                return new FuelFilter();
            }   
        };
    }   
}

class AirlFilter extends Filter{
    public static Factory<AirlFilter> factory(){
        return new Factory<AirlFilter>(){
            @Override
            public AirlFilter create() {
                // TODO Auto-generated method stub
                return new AirlFilter();
            }   
        };
    }   
}
class CabinAirlFilter extends Filter{
    public static Factory<CabinAirlFilter> factory(){
        return new Factory<CabinAirlFilter>(){
            @Override
            public CabinAirlFilter create() {
                // TODO Auto-generated method stub
                return new CabinAirlFilter();
            }   
        };
    }   
}
class OilFilter extends Filter{
    public static Factory<OilFilter> factory(){
        return new Factory<OilFilter>(){
            @Override
            public OilFilter create() {
                // TODO Auto-generated method stub
                return new OilFilter();
            }   
        };
    }   
}

class Belt extends Part{}

class FanBelt extends Belt{
    public static Factory<FanBelt> factory(){
        return new Factory<FanBelt>(){

            @Override
            public FanBelt create() {
                // TODO Auto-generated method stub
                return new FanBelt();
            }
            
        };
    }
}

class GeneratorBelt extends Belt{
    public static Factory<GeneratorBelt> factory(){
        return new Factory<GeneratorBelt>(){

            @Override
            public GeneratorBelt create() {
                // TODO Auto-generated method stub
                return new GeneratorBelt();
            }
            
        };
    }
}

class PowerSteeringBelt extends Belt{
    public static Factory<PowerSteeringBelt> factory(){
        return new Factory<PowerSteeringBelt>(){

            @Override
            public PowerSteeringBelt create() {
                // TODO Auto-generated method stub
                return new PowerSteeringBelt();
            }
            
        };
    }
}