接口隔离原则
接口隔离原则(Interface Segregation Principle)
1、 基本介绍
-
客户端不应该依赖它不需要的接 口,即一个类对另一个类的依赖 应该建立在最小的接口上
-
先看一张图:
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类A通过接口Interface1依赖类B,类C通过 接口Interface1依赖类D,如果接口 Interface1对于类A和类C来说不是最小接口, 那么类B和类D必须去实现他们不需要的方法。
-
按隔离原则应当这样处理: 将接口Interface1拆分为独立的几个接口, 类A和类C分别与他们需要的接口建立依赖关系。也就是采用接口隔离原则
2、idea画类图
@startuml
interface Interface1{
void operation1();
void operation2();
void operation3();
void operation4();
void operation5();
}
class A
class B
class C
class D
A ..> Interface1
C ..> Interface1
B ..|> Interface1
D ..|> Interface1
@enduml
查看类图:
3、实现上面的类图
package com.sddm.princle.segregation;
public class Segregation1 {
public static void main(String[] args) {
}
}
//接口
interface Interface1 {
void operation1();
void operation2();
void operation3();
void operation4();
void operation5();
}
class B implements Interface1{
@Override
public void operation1() {
System.out.println("B 实现了operation1");
}
@Override
public void operation2() {
System.out.println("B 实现了operation2");
}
@Override
public void operation3() {
System.out.println("B 实现了operation3");
}
@Override
public void operation4() {
System.out.println("B 实现了operation4");
}
@Override
public void operation5() {
System.out.println("B 实现了operation5");
}
}
class D implements Interface1{
@Override
public void operation1() {
System.out.println("D 实现了operation1");
}
@Override
public void operation2() {
System.out.println("D 实现了operation2");
}
@Override
public void operation3() {
System.out.println("D 实现了operation3");
}
@Override
public void operation4() {
System.out.println("D 实现了operation4");
}
@Override
public void operation5() {
System.out.println("D实现了operation5");
}
}
class A {
//A 类通过接口Interface1 依赖(使用)B类,但是只会用到1,2,3方法
public void depend1(Interface1 i){
i.operation1();
}
public void depend2(Interface1 i){
i.operation2();
}
public void depend3(Interface1 i){
i.operation3();
}
}
class C {
//A 类通过接口Interface1 依赖(使用)D类,但是只会用到1,4,5方法
public void depend1(Interface1 i){
i.operation1();
}
public void depend4(Interface1 i){
i.operation4();
}
public void depend5(Interface1 i){
i.operation5();
}
}
不过这样子没有遵循接口隔离原则
进行优化
package com.sddm.princle.segregation.improve;
public class Segregation1 {
public static void main(String[] args) {
//使用一把
A a = new A();
a.depend1(new B());// A类通过接口去依赖B类
a.depend2(new B());
a.depend3(new B());
C c = new C();
c.depend1(new D());// D类通过接口去依赖B类
c.depend4(new D());
c.depend5(new D());
}
}
//接口1
interface Interface1 {
void operation1();
}
//接口2
interface Interface2 {
void operation2();
void operation3();
}
//接口3
interface Interface3 {
void operation4();
void operation5();
}
class B implements Interface1,Interface2 {
@Override
public void operation1() {
System.out.println("B 实现了operation1");
}
@Override
public void operation2() {
System.out.println("B 实现了operation2");
}
@Override
public void operation3() {
System.out.println("B 实现了operation3");
}
}
class D implements Interface1,Interface3 {
@Override
public void operation1() {
System.out.println("D 实现了operation1");
}
@Override
public void operation4() {
System.out.println("D 实现了operation4");
}
@Override
public void operation5() {
System.out.println("D 实现了operation5");
}
}
class A {
//A 类通过接口Interface1,类通过接口Interface2 依赖(使用)B类,但是只会用到1,2,3方法
public void depend1(Interface1 i) {
i.operation1();
}
public void depend2(Interface2 i) {
i.operation2();
}
public void depend3(Interface2 i) {
i.operation3();
}
}
class C {
//C 类通过接口Interface1,类通过接口Interface3 依赖(使用)D类,但是只会用到1,4,5方法
public void depend1(Interface1 i) {
i.operation1();
}
public void depend4(Interface3 i) {
i.operation4();
}
public void depend5(Interface3 i) {
i.operation5();
}
}
查看结果: