面向对象-继承与多态

继承

在Java中，继承是一种重要的面向对象编程概念，它允许子类（派生类）从父类（基类）继承属性和方法。继承的主要目的是实现代码重用和建立类之间的关系，使代码更加模块化和易于维护。

在Oinone平台中，关于函数的继承涉及到了命名空间（namespace）的概念，这在Java中并不是直接的概念，但我们可以理解为类和包名的概念。

假设我们有一个父类 PetShop，它有一个 sayHello 的函数。子类可以继承 PetShop 并且自动拥有 sayHello 函数，这是继承的一种体现。子类继承了父类的方法，也可以添加自己的新方法。

子类在继承父类的方法时，会继承相同的函数名称和函数签名，因此在命名空间中保持一致。这样做的好处是保持了统一的接口，使得使用继承的代码更加清晰和易于维护。

多态

Oinone的多态，我们只提供覆盖功能，不提供重载，因为Oinone相同 name和fun的情况下不会去识别参数个数和类型。

多态实践

Step1 为PetShop新增hello函数

package pro.shushi.pamirs.demo.api.model;
…… //import

@Model.model(PetShop.MODEL_MODEL)
@Model(displayName = "宠物店铺",summary="宠物店铺",labelFields ={"shopName"} )
public class PetShop extends AbstractDemoIdModel {
    public static final String MODEL_MODEL="demo.PetShop";
 
    …… //省略其他代码
    @Function(openLevel = FunctionOpenEnum.API)
    @Function.Advanced(type= FunctionTypeEnum.QUERY)
    public PetShop sayHello(PetShop shop){
        PamirsSession.getMessageHub().info("Hello:"+shop.getShopName());
        return shop;
    }
    
    @Function(name = "sayHello2",openLevel = FunctionOpenEnum.API)
    @Function.Advanced(type= FunctionTypeEnum.QUERY)
    @Function.fun("sayHello2")
    public PetShop sayHello(PetShop shop, String s) {
        PamirsSession.getMessageHub().info("Hello:"+shop.getShopName()+",s:"+s);
        return shop;
    }

    @Function(openLevel = FunctionOpenEnum.API)
    @Function.Advanced(type= FunctionTypeEnum.QUERY)
    public PetShop hello(PetShop shop){
        PamirsSession.getMessageHub().info("Hello:"+shop.getShopName());
        return shop;
    }
}

Step2 为PetShopProxyB新增对应的三个函数

其中PetShopProxyB新增的hello函数，在java中是重载了hello，在代码中new PetShopProxyB()是可以调用父类的sayHello单参方法，也可以调用本类的双参方法。但在oinone的体系中对于PetShopProxyB只有一个可识别的Fucation就是双参的sayHello

package pro.shushi.pamirs.demo.api.proxy;
…… //import

@Model.model(PetShopProxyB.MODEL_MODEL)
@Model.Advanced(type = ModelTypeEnum.PROXY,inherited ={PetShopProxy.MODEL_MODEL,PetShopProxyA.MODEL_MODEL} )
@Model(displayName = "宠物店铺代理模型B",summary="宠物店铺代理模型B")
public class PetShopProxyB extends PetShop {

    public static final String MODEL_MODEL="demo.PetShopProxyB";

    @Field.one2many
    @Field(displayName = "萌猫商品列表")
    @Field.Relation(relationFields = {"id"},referenceFields = {"shopId"})
    private List<PetCatItem> catItems;

    @Function(openLevel = FunctionOpenEnum.API)
    @Function.Advanced(type= FunctionTypeEnum.QUERY)
    public PetShop sayHello(PetShop shop){
        PamirsSession.getMessageHub().info("PetShopProxyB Hello:"+shop.getShopName());
        return shop;
    }

    @Function(name = "sayHello2",openLevel = FunctionOpenEnum.API)
    @Function.Advanced(type= FunctionTypeEnum.QUERY)
    @Function.fun("sayHello2")
    public PetShop sayHello(PetShop shop,String hello){
        PamirsSession.getMessageHub().info("PetShopProxyB say:"+hello+","+shop.getShopName());
        return shop;
    }
    @Function(openLevel = FunctionOpenEnum.API)
    @Function.Advanced(type= FunctionTypeEnum.QUERY)
    public PetShop hello(PetShop shop,String hello){
        PamirsSession.getMessageHub().info("PetShopProxyB hello:"+hello+","+shop.getShopName());
        return shop;
    }
}

Step3 重启看效果

1. 查看petShopQuery的sayHello、sayHello2、hello三个函数，结果正常
2. 查看petShopProxyBQuery的sayHello、sayHello2、hello三个函数结果都被重载了，而且hello函数传不传参数hello，都是调用的本类的双参函数

query{
  petShopQuery{
    sayHello(shop:{shopName:"cpc"}){
      shopName
    }
    sayHello2(shop:{shopName:"cpc"},s:"sss"){
      shopName
    }
    hello(shop:{shopName:"cpc"}){
      shopName
    }
  }
  petShopProxyBQuery{
    sayHello(shop:{shopName:"cpc"}){
      shopName
    }
    sayHello2(shop:{shopName:"cpc"},hello:"sss"){
      shopName
    }
    hello(shop:{shopName:"cpc"},hello:"hello"){
      shopName
    }
  }
}