Structural Patterns Part 1/7: Adapter Pattern
Structural Patterns Part 1/7: Adapter Pattern
目录
Definition
Adapter Pattern是连接两个互不兼容或者互相独立的类或接口的桥梁。
一个现实中的例子就是读卡器,连接电脑和内存卡。读卡器就是Adapter,内存卡就是Adaptee,电脑就是Client了。
一句话(英文更好理解):
A class extends another class, takes in an object, and makes the taken object behave like the extended class.
何时使用?当希望连接两个互不兼容或者互相独立的类或接口时。
使用频率: Medium High
UML Class Diagram
Implementation
读卡器负责读卡,光驱负责读光盘。
// Reader.java
package designpatternsstructuralpatterns.adapter;
public interface Reader {
void read();
}
// ReaderImpl.java
package designpatternsstructuralpatterns.adapter;
class CardReader implements Reader {
Card card;
public CardReader(Card card) {
this.card = card;
}
@Override
public void read() {
card.dataOutPut();
}
}
class DiskReader implements Reader {
Disk disk;
public DiskReader(Disk disk) {
this.disk = disk;
}
@Override
public void read() {
disk.dataOutPut();
}
}
class Card {
void dataOutPut() {
System.out.println("Card::DATA");
}
}
class Disk {
void dataOutPut() {
System.out.println("Disk::DATA");
}
}
// AdapterDemo.java
package designpatternsstructuralpatterns.adapter;
public class AdapterDemo {
public static void main(String[] args) {
Computer computer = new Computer();
computer.read(new CardReader(new Card()));
computer.read(new DiskReader(new Disk()));
}
}
class Computer {
public void read(Reader reader) {
reader.read();
}
}
// output
Card::DATA
Disk::DATA