工厂模式:父类决定实例的生成方式,但并不决定所要生成的具体的类。
示例:制作身份证
Product类:(Product)
package framework;
public abstract class Product {
public abstract void use();
}
Factory类:(Factory)
package framework;
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);
}
IDCard类:(ConcreteProduct)
package idcard;
import framework.*;
public class IDCard extends Product {
private String owner;
IDCard(String owner) {
System.out.println("制作" + owner + "的ID卡。");
this.owner = owner;
}
public void use() {
System.out.println("使用" + owner + "的ID卡。");
}
public String getOwner() {
return owner;
}
}
IDCardFactory类:(ConcreteFactory)
package idcard;
import framework.*;
import java.util.*;
public class IDCardFactory extends Factory {
private List owners = new ArrayList();
protected Product createProduct(String owner) {
return new IDCard(owner);
}
protected void registerProduct(Product product) {
owners.add(((IDCard)product).getOwner());
}
public List getOwners() {
return owners;
}
}
Main类:
import framework.*;
import idcard.*;
public class Main {
public static void main(String[] args) {
Factory factory = new IDCardFactory();
Product card1 = factory.create("小明");
Product card2 = factory.create("小红");
Product card3 = factory.create("小刚");
card1.use();
card2.use();
card3.use();
}
}
Product | 抽象类,生成实例所持有的接口(API) |
Factory | 抽象类,负责生成Product角色 |
ConcreteProduct | 决定具体的产品 |
ConcreteFactory | 生成具体的产品 |