裝飾者模式指在無須改變原有類及類的關係的情況下，動態擴充套件一個類的功能。它通過裝飾者來包裹真實的物件，並動態地向物件新增或者撤銷功能。

（1）定義Sourceable介面

public interface Sourceable{
    public void createComputer();
}

（2）定義Sourceable介面的實現類

public class Source implements Sourceable{
    private final static Log logger = LogFactory.getLog(Source.class);
    @Override
    
 
public void createComputer(){
        logger.info("create computer by Source");
    }
}

（3）定義裝飾者類

public class Decorator implements Sourceable{
    private final static Log logger = LogFactory.getLog(Decorator.class);

    private Sourceable source;
    public Decorator(Sourceable source){
        
 
super();
        this.source = source;
    }

    @Override
    public void createComputer(){
        source.createComputer();
        logger.info("make system");
    }
}

Decorator擴充套件了原來的source的功能

（4）使用

public static void main(String[] args){
    Sourceable source = new Source();
    Sourceable obj 
 
= new Decorator(source);
    obj.createComputer();
}