Bridging application scenarios:
1.jdbc driver
2. AWT's Peer Architecture
3. Bank log management:
Format classification: operation log, transaction log, exception log
Distance classification: local logging, remote logging
4. Bonus calculation in HR system:
Bonus department: individual bonus, group bonus, incentive bonus
Department classification: personnel department, sales department, R&D department
5.Message processing of the oa system:
Service type: ordinary message, urgent message, special message
Sending message: system message, SMS, email
Scenario: Common product classification in the mall system, taking a computer as an example, how to deal with the problem of product classification?
For example, the multi-level integration structure is shown in the figure:
But this will encounter a scalability problem:
If you want to add a new type of computer, you must add a class under each brand, add a new brand, and also add a class for each computer type.
First take the way of not using bridge, class diagram:
computer
package com.gcxzflgl.bridge;
public interface Computer {
void sale();
}
class Desktop implements Computer {
@Override
public void sale() {
System.out.println("Selling desktops!");
}
}
class Laptop implements Computer {
@Override
public void sale() {
System.out.println("Sale notebook!");
}
}
class Pad implements Computer {
@Override
public void sale() {
System.out.println("Selling tablets!");
}
}
class LenovoDesktop extends Desktop {
@Override
public void sale() {
System.out.println("Selling Lenovo Desktops");
}
}
class LenovoLaptop extends Laptop {
@Override
public void sale() {
System.out.println("Selling Lenovo Notebooks");
}
}
class LenovoPad extends Pad {
@Override
public void sale() {
System.out.println("Selling Lenovo Tablet");
}
}
class ShenzhouDesktop extends Desktop {
@Override
public void sale() {
System.out.println("Sales Shenzhou Desktop");
}
}
class ShenzhouLaptop extends Laptop {
@Override
public void sale() {
System.out.println("Sales Shenzhou Notebook");
}
}
class ShenzhouPad extends Pad {
@Override
public void sale() {
System.out.println("Sales Shenzhou Tablet PC");
}
}
class DellDesktop extends Desktop {
@Override
public void sale() {
System.out.println("Selling Dell Desktops");
}
}
class DellLaptop extends Laptop {
@Override
public void sale() {
System.out.println("Selling Dell Notebooks");
}
}
class DellPad extends Pad {
@Override
public void sale() {
System.out.println("Selling Dell Tablets");
}
}
Client call:
package com.gcxzflgl.bridge;
public class Client {
public static void main(String[] args) {
//Sell Lenovo's laptops
Computer c = new Laptop();
Laptop l = new LenovoLaptop();
c.sale();
l.sale();
}
}
The above method is difficult to maintain in actual development
The following bridge mode is reasonably designed as such
Class Diagram:
Create a brand class:
package com.gcxzflgl.bridge;
/**
* brand
* @author Administrator
*
*/
public interface Brand {
void sale();
}
class Lenovo implements Brand {
@Override
public void sale() {
System.out.println("Selling Lenovo Computers");
}
}
class Dell implements Brand {
@Override
public void sale() {
System.out.println("Selling Dell computers");
}
}
class Shenzhou implements Brand {
@Override
public void sale() {
System.out.println("Sales Shenzhou Computer");
}
}
Create the computer class:
package com.gcxzflgl.bridge;
/**
* Dimensions of computer type
* @author Administrator
*
*/
public class Computer2 {
protected Brand brand;
public Computer2(Brand b) {
this.brand = b;
}
public void sale(){
brand.sale();
}
}
class Desktop2 extends Computer2 {
public Desktop2(Brand b) {
super(b);
}
@Override
public void sale() {
super.sale();
System.out.println("Selling Desktop");
}
}
class Laptop2 extends Computer2 {
public Laptop2(Brand b) {
super(b);
}
@Override
public void sale() {
super.sale();
System.out.println("Sales Notebook");
}
}
Client call:
package com.gcxzflgl.bridge;
public class Client {
public static void main(String[] args) {
//Sell Lenovo's laptops
Computer c = new Laptop();
Laptop l = new LenovoLaptop();
c.sale();
l.sale();
//Sell Shenzhou's desktop
Computer2 c2 = new Desktop2(new Shenzhou());
c2.sale();
}
}