Abstract factory and its improvement examples

This article will use Reflection mechanism and configuration file improvement Abstract factory .
Abstract factory example
The structure is as follows ：

AbstractComputer,AbstractDisplay be similar , They are all abstract products .

public class AbstractComputer {
    
  protected String manufacturerName="";
protected String modelName="";
  public String showDetails(){
    
    return " The manufacturer is  "+manufacturerName+" Models for  "+modelName;
  }
}

AppleComputer,DellComputer Class inherited AbstractComputer, Realize specific products . The relationship between abstract products and specific products for display types is similar , The code is as follows ：

public class AppleComputer extends AbstractComputer{
    
  protected String manufacturerName="APPLE";
  protected String modelName="Q1";
  public String showDetails(){
    
    return " The manufacturer is  "+manufacturerName+" Models for  "+modelName;
  }
}

DeviceFactory Is an abstract factory class , Contains multiple ways to create a product , You can create Computer And other products of different types .

public abstract class DeviceFactory {
    
//  Create a computer 
  abstract public AbstractComputer CreateComputer();
//  Create a monitor 
  abstract public AbstractDisplay CreateDisplay();
}

AppleFactory Inherited DeviceFactory, Implement multiple abstract methods in the abstract factory , Complete the creation of specific products .DellFactory be similar .

public class AppleFactory extends DeviceFactory {
    
  public AbstractComputer CreateComputer(){
    
    return  new AppleComputer();
  }
  public AbstractDisplay
  CreateDisplay(){
    
    return  new AppleDisplay();
  }
}

Test client

public class Test {
    
  public static void main(String[] args) {
    
      AbstractComputer myPC;
      AbstractDisplay myDisplay;
      DeviceFactory factory=new DellFactory();
// DeviceFactory factory=new AppleFactory();
    myPC=factory.CreateComputer();
      myDisplay=factory.CreateDisplay();
System.out.println(" The computer ："+myPC.showDetails());
System.out.println(" Monitor ："+myDisplay.showDetails());

  }
}

uml As shown in the figure ：

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Next, use reflection mechanism and configuration file to improve the abstract factory example .
Introduce configuration files into the structure , Delete all factories , Leave only DeviceFactory, Other classes remain unchanged .

The configuration file Device.properties

#DeviceComputer=AppleComputer
#DeviceDisplay=AppleDisplay

DeviceComputer=DellComputer
DeviceDisplay=DellDisplay

factory DeviceFactory

public class DeviceFactory {
    

  public static Properties properties = new Properties();
  public static File file = new File("src\\Device.properties");
    public static AbstractComputer CreateComputer() throws Exception{
    
      properties.load(new FileInputStream(file));
      return (AbstractComputer)Class.forName(properties.getProperty("DeviceComputer")).newInstance();
    };
  public static AbstractDisplay CreateDisplay() throws Exception{
    
    return (AbstractDisplay)Class.forName(properties.getProperty("DeviceDisplay")).newInstance();
  };
}

Test client

public class Test {
    
  public static void main(String[] args) throws Exception {
    
     AbstractComputer myPC;
      AbstractDisplay myDisplay;
      myPC=DeviceFactory.CreateComputer();
      myDisplay=DeviceFactory.CreateDisplay();
    System.out.println(" The computer ："+myPC.showDetails());
    System.out.println(" Monitor ："+myDisplay.showDetails());
  }
}

uml Class diagram ：