java设计模式之composite pattern...

abstract class Entry{
    public abstract String getName();
    public abstract int getSize();
    public Entry add(Entry entry)throws FileTreatmentException{
        throw new FileTreatmentException();
    }
    public void printList(){
        printList("");
    }
    protected abstract void printList(String prefix);
    public String toString(){
        return getName() + " (" + getSize() + ")";
    }
}

class File extends Entry{
    private String name;
    private int size;
    public File(String name, int size){
        this.name = name;
        this.size = size;
    }
    public String getName(){
        return name;
    }
    public int getSize(){
        return size;
    }
    protected void printList(String prefix){
        System.out.println(prefix + "/" + this);
    }
}

class Directory extends Entry{
    private String name;
    private Vector directory = new Vector();
    public Directory(String name){
        this.name = name;
    }
    public String getName(){
        return name;
    }
    public int getSize(){
        int size = 0;
        Iterator it = directory.iterator();
        while(it.hasNext()){
            Entry entry = (Entry)it.next();
            size += entry.getSize();
        }
        return size;
    }
    public Entry add(Entry entry){
        directory.add(entry);
        return this;
    }
    protected void printList(String prefix){
        System.out.println(prefix + "/" + this);
        Iterator it = directory.iterator();
        while(it.hasNext()){
            Entry entry = (Entry)it.next();
            entry.printList(prefix + "/" + name);
        }
    }
}

class FileTreatmentException extends RuntimeException{
    public FileTreatmentException(){
    }
    public FileTreatmentException(String msg){
        super(msg);
    }
}
public class Composite {
    public static void main(String[] args) {
        try{
            System.out.println("Making root entries...");
            Directory rootdir = new Directory("root");
            Directory bindir = new Directory("bin");
            Directory tmpdir = new Directory("tmp");
            Directory usrdir = new Directory("usr");
            rootdir.add(bindir);
            rootdir.add(tmpdir);
            rootdir.add(usrdir);
            bindir.add(new File("vi", 10000));
            bindir.add(new File("latex", 20000));
            rootdir.printList();
            System.out.println("");
            System.out.println("Making user entries...");
            Directory yuki = new Directory("yuki");
            Directory hanako = new Directory("hanako");
            Directory tomura = new Directory("tomura");
            usrdir.add(yuki);
            usrdir.add(hanako);
            usrdir.add(tomura);
            yuki.add(new File("diary.html", 100));
            yuki.add(new File("Composite.java", 200));
            hanako.add(new File("memo.tex", 300));
            tomura.add(new File("game.doc", 400));
            tomura.add(new File("junk.mail", 500));
            rootdir.printList();
        } catch (FileTreatmentException e) {
            e.printStackTrace();
        }
    }
}