# 接口隔离原则(ISP)

**接口隔离原则(Interface Segregation Principle, ISP)**：使用多个专门的接口，而不使用单一的总接口，即客户端不应该依赖那些它不需要的接口。

* 一个类对一个类的依赖应该建立在最小的接口上
* 建立单一接口不要建立庞大臃肿的接口
* 尽量细化接口，接口中的方法应该尽量少

**在使用接口隔离原则时，我们需要注意控制接口的粒度，接口不能太小，如果太小会导致系统中接口泛滥，不利于维护；接口也不能太大，太大的接口将违背接口隔离原则，灵活性较差，使用起来很不方便。**一般而言，接口中仅包含为某一类用户定制的方法即可，不应该强迫客户依赖于那些它们不用的方法。这符合我们经常说的，高内聚，低耦合的思想。从而使程序具有很好的可读性，可维护性，可扩展性。

## Golang Demo

```go
package interfacesegregation

// 生产中根据实际情况，将接口拆分到不同的文件中
type EatAnimalAction interface {
    eat()
}
type FlyAnimalAction interface {
    fly()
}
type SwimAnimalAction interface {
    swim()
}
```

```go
package interfacesegregation

import "fmt"

type Bird struct {
}

func (Bird) fly() {
    fmt.Println("bird fly")
}

func (Bird) eat() {
    fmt.Println("bird eat")
}
```

```go
package interfacesegregation

import "fmt"

type Dog struct {
}

func (Dog) swim() {
    fmt.Println("dog swim")
}

func (Dog) eat() {
    fmt.Println("dog eat")
}
```

## Java Demo

假设我们有这样一个接口，定义了动物的行为。

```java
package tech.selinux.design.principle.interfacesegregation;

public interface IAnimalAction {
  void eat();

  void fly();

  void swim();
}
```

但是，如果我们有一个实现类，例如Dog,并不需要实现fly的方法，因此这个接口中定义的方法就显得冗余复杂。这时接口隔离原则的作用就体现出来了。

```java
package tech.selinux.design.principle.interfacesegregation;

public interface IEatAnimalAction {
  void eat();
}
```

```java
package tech.selinux.design.principle.interfacesegregation;

public interface IFlyAnimalAction {
  void fly();
}
```

```java
package tech.selinux.design.principle.interfacesegregation;

public interface ISwimAnimalAction {
  void swim();
}
```

```java
package tech.selinux.design.principle.interfacesegregation;

public class Dog implements ISwimAnimalAction, IEatAnimalAction {

  @Override
  public void eat() {}

  @Override
  public void swim() {}
}
```

```java
package tech.selinux.design.principle.interfacesegregation;

public class Bird implements IEatAnimalAction,IFlyAnimalAction {
  @Override
  public void eat() {}

  @Override
  public void fly() {}

}
```

## UML

![接口隔离原则UML](/files/-LcZ6HrWYuOZgogcmaBj)

### 补充另一个版本的Java/Scala Demo 以及源码解析

## Java Demo\_

## Scala Demo

## UML\_

## 源码解析


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://www.selinux.tech/designpattern/seven-principle/interface-segregation-principle.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.