定义一个创建对象的接口,让子类决定实例化哪个类,使得一个类的实例化延迟到其子类。
1.工厂接口Factory
public abstract class Factory {
public final Product create(String owner) {
Product p = createProduct(owner);
registerProduct(p);
return p;
}
protected abstract Product createProduct(String owner);
protected abstract void registerProduct(Product product);
}
2.产品接口Product
public abstract class Product {
public abstract void use();
}
3.工厂实现IDCardFactory
import framework.*;
import java.util.*;
public class IDCardFactory extends Factory {
private Vector owners = new Vector();
protected Product createProduct(String owner) {
return new IDCard(owner);
}
protected void registerProduct(Product product) {
owners.add(((IDCard)product).getOwner());
}
public Vector getOwners() {
return owners;
}
}
4.产品实现IDCard
import framework.*;
public class IDCard extends Product {
private String owner;
IDCard(String owner) {
System.out.println("建立" + owner + "的卡。");
this.owner = owner;
}
public void use () {
System.out.println("使用" + owner + "的卡。");
}
public String getOwner() {
return owner;
}
}
5.主函数Main
import framework.*;
public class Main {
public static void main(String[] args) {
Factory factory = new IDCardFactory();
Product card1 = factory.create("乔峰");
Product card2 = factory.create("令狐冲");
Product card3 = factory.create("武松");
card1.use();
card2.use();
card3.use();
}
}