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Java设计模式之Composite Pattern介绍

2010-09-19

abstract class Entry{    public abstract String getName();    public abstract int getSize();    public Entry add(Entry entry)throws FileTreatmentException{   &n

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();
}
}
}
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