抽象类实现接口是好还是坏？ [英] Is it good or bad for an abstract class to implement an interface?

问题描述

抽象类实现接口是好还是坏？

Is it good or bad for an abstract class to implement an interface?

以下两个例子都有效，但哪一个让对你更有意义

？

both examples below works, but which one makes more sense to you?

选项1，

interface A {
    function foo();
}

abstract class B implements A {
    abstract public function foo();
}

class C extends B {
    public function foo() {
        echo 'works';
    }
}

$o = new C();
$o->foo();

选项2，

interface A {
    function foo();
}

abstract class B implements A {
}

class C extends B {
    public function foo() {
        echo 'works';
    }
}

$o = new C();
$o->foo();

推荐答案

在option2中，classB不会对你的语义添加任何内容应用程序，所以完全没必要。如果您不需要在抽象类中实现某些共享（通过所有子类）功能，则应该最好直接从接口派生，以使事情不必要地复杂化。

In option2, classB adds nothing to the semantics of your application, so it is completely unnecessary. If you do not have any need to implement some shared (by all subclasses) functionality in the abstract class, you should better derive directly from the interface, to make things not unnecessarily complicated.

在这种情况下，整个事情可能有意义地简化为：

In this case, the whole thing could be sensefully simplyfied to:

interface A 
{
    function foo();
}

class C implements A 
{
    public function foo() {
        echo 'works';
    }
}

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