Java程序员的日常 —— 注册工厂的妙用

//创建
class 沙发{}
class 椅子{}
class 茶几{}

//使用
new 沙发();
new 椅子();
new 椅子();
new 茶几();

//定义创建工厂
interface Factory<T>{ 
    T create();
}

//对象继承这个工厂
class 沙发 extends 家具{
    public static class Factory implements a.b.c.Factory<沙发>{
    public 沙发 create(){ return new 沙发()}
    }
}
class 茶几 extends 家具{
    public static class Factory implements a.b.c.Factory<茶几>{
    public 茶几 create(){ return new 茶几()}
    }
}
class 椅子 extends 家具{
    public static class Factory implements a.b.c.Factory<椅子>{
    public 椅子 create(){ return new 椅子()}
    }
}

//注册到工厂Map中
Map<String,Factory<? extends 家具>> map = new HashMap<>();
map.put("沙发",new 沙发.Factory());
map.put("椅子",new 椅子.Factory());
map.put("茶几",new 茶几.Factory());

//这样在使用的时候，就可以直接用它创建对象了
map.get("沙发").create()

package xing.test.thinking.chap14;

public interface Factory<T> {
    T create();
}

package xing.test.thinking.chap14;

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

class Part {
    public String toString(){
        return getClass().getSimpleName();
    }
    static List<Factory<? extends Part>> partFactories = new ArrayList<Factory<? extends Part>>();//存放所有的对象工厂
    //在静态块中添加对象工厂
    static{
        partFactories.add(new FuelFilter.Factory());
        partFactories.add(new AirFilter.Factory());
        partFactories.add(new CabinAirFilter.Factory());
        partFactories.add(new OilFilter.Factory());
        partFactories.add(new FanBelt.Factory());
        partFactories.add(new PowerSteeringBelt.Factory());
        partFactories.add(new GeneratorBelt.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{}
class FuelFilter extends Filter {
    public static class Factory implements xing.test.thinking.chap14.Factory<FuelFilter> {
        public FuelFilter create(){
            return new FuelFilter();
        }
    }
}
class AirFilter extends Filter {
    public static class Factory implements xing.test.thinking.chap14.Factory<AirFilter> {
        public AirFilter create(){
            return new AirFilter();
        }
    }
}
class CabinAirFilter extends Filter {
    public static class Factory implements xing.test.thinking.chap14.Factory<CabinAirFilter> {
        public CabinAirFilter create(){
            return new CabinAirFilter();
        }
    }
}
class OilFilter extends Filter {
    public static class Factory implements xing.test.thinking.chap14.Factory<OilFilter> {
        public OilFilter create(){
            return new OilFilter();
        }
    }
}
class Belt extends Part{};
class FanBelt extends Belt {
    public static class Factory implements xing.test.thinking.chap14.Factory<FanBelt> {
        public FanBelt create(){
            return new FanBelt();
        }
    }
}
class GeneratorBelt extends Belt {
    public static class Factory implements xing.test.thinking.chap14.Factory<GeneratorBelt> {
        public GeneratorBelt create(){
            return new GeneratorBelt();
        }
    }
}
class PowerSteeringBelt extends Belt {
    public static class Factory implements xing.test.thinking.chap14.Factory<PowerSteeringBelt> {
        public PowerSteeringBelt create(){
            return new PowerSteeringBelt();
        }
    }
}
public class RegisteredFactories {
    public static void main(String[] args) {
        for(int i=0 ; i<10 ; i++){
            System.out.println(Part.createRandom());
        }
    }
}