软件设计-组合模式

import java.util.ArrayList;
import java.util.List;

public class 组合模式 {
    public static void main(String[] args)
    {
        AbstractFile fileA=new File("fileA");
        AbstractFile fileB=new File("fileB");
        //fileA.printName();

        AbstractFile folderB=new Folder("folderB");
        AbstractFile folderA=new Folder("folderA");
        //folderB.printName();

        AbstractFile root=new Folder("root");

        root.Add(fileA);
        root.Add(folderA);
        folderA.Add(fileB);
        folderA.Add(folderB);

        print(root);
    }
    static void print(AbstractFile file)
    {
        file.printName();
        List<AbstractFile> list=file.getCildern();
        if(list==null)
            return ;
        for(AbstractFile children : list)
        {
            //children.printName();     错误的
            print(children);
        }
    }
}
abstract class AbstractFile{
    protected String name;

    public abstract boolean Add(AbstractFile file);
    public abstract boolean Remove(AbstractFile file);
    public abstract List<AbstractFile> getCildern();

    public void printName()
    {
        System.out.println(name);
    }

}
class File extends AbstractFile{

    public File(String name)
    {
        this.name=name;
    }
    @Override
    public boolean Add(AbstractFile file)
    {
        return false;
    }
    @Override
    public boolean Remove(AbstractFile file)
    {
        return false;
    }
    @Override
    public List<AbstractFile> getCildern()
    {
        return null;
    }
}

class Folder extends AbstractFile{
    private List<AbstractFile> list =new ArrayList<AbstractFile>();
    public Folder(String name)
    {
        this.name=name;
    }
    @Override
    public boolean Add(AbstractFile file)
    {
        return list.add(file);
    }
    @Override
    public boolean Remove(AbstractFile file)
    {
        return list.remove(file);
    }
    @Override
    public List<AbstractFile> getCildern()
    {
        return list;
    }
}

运行结果