工厂模式是用模板模式来构建生成实例的工厂。Factory Method模式中,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,具体的处理全部交给子类完成。
该模式在于把 框架 和 具体加工 分别开来,进行分别封装。框架类不需要修改
1,先编写生产框架
Product类 抽象产品类
Product.java
抽象产品类只要定义统一的抽象使用方法
package factorymethod.framwork;
public abstract class Product {
public abstract void use();
}
Factory类 抽象生产工厂框架
和模板模式相同定义抽象方法,非抽象方法调用抽象放啊
package factorymethod.framwork;
public abstract class Factory {
public final Product create(String owner) {
Product p = createProduct(owner);//调用抽象方法
registerProduct(p);
return p;
}
protected abstract Product createProduct(String owner);//定义抽象方法
protected abstract void registerProduct(Product product);
}
2. 编写具体实现
IDCard.java 产品的具体实现
package factorymethod.idcard;
import factorymethod.framwork.Product;
public class IDCard extends Product {
private String owner;
IDCard(String owner) {
System.out.println("make " + owner + "'s ID card");
this.owner = owner;
}
@Override
public void use() {
System.out.println("use " + owner + "'s ID card");
}
public String getOwner() {
return owner;
}
}
IDCardFactory.java 工厂的具体实现
继承抽线工厂类,实现抽象方法,调用父类方法进行生产
package factorymethod.idcard;
import factorymethod.framwork.*;
import java.util.*;
public class IDCardFactory extends Factory{
private List owners = new ArrayList();
@Override
protected Product createProduct(String owner) {
return new IDCard(owner);
}
@Override
protected void registerProduct(Product product) {
owners.add(((IDCard)product).getOwner());
}
public List getOwners() {
return owners;
}
}
测试
package factorymethod.idcard;
import factorymethod.framwork.Factory;
import factorymethod.framwork.Product;
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();
}
}