java/src/main/com/google/appengine/tools/util/FileIterator.java

   1 // Copyright 2009, Google Inc.  All rights reserved.
   2
   3 package com.google.appengine.tools.util;
   4
   5 import java.io.File;
   6 import java.util.Arrays;
   7 import java.util.Iterator;
   8 import java.util.LinkedList;
   9 import java.util.NoSuchElementException;
  10
  11 /**
  12  * Walks a directory tree, returning all the files.
  13  *
  14  *
  15  */
  16 public class FileIterator implements Iterator<File>, Iterable<File> {
  17   private LinkedList<File> dirs = new LinkedList<File>();
  18   private Iterator<File> files;
  19   private File next;
  20
  21   public FileIterator(File base) {
  22     File[] baseFiles = base.listFiles();
  23     if (baseFiles != null) {
  24       files = Arrays.asList(baseFiles).iterator();
  25     }
  26     _next();
  27   }
  28
  29   @Override
  30   public boolean hasNext() {
  31     return next != null;
  32   }
  33
  34   @Override
  35   public File next() {
  36     if (next == null) {
  37       throw new NoSuchElementException();
  38     }
  39     return _next();
  40   }
  41
  42   private File _next() {
  43     File result = next;
  44     next = null;
  45     while (files != null) {
  46       try {
  47         File f = files.next();
  48         if (f.isDirectory()) {
  49           dirs.add(f);
  50         } else {
  51           next = f;
  52           break;
  53         }
  54       } catch (NoSuchElementException ex) {
  55         if (dirs.isEmpty())
  56           files = null;
  57         else
  58           files = Arrays.asList(dirs.removeFirst().listFiles()).iterator();
  59       }
  60     }
  61     return result;
  62   }
  63
  64   @Override
  65   public void remove() {
  66     throw new UnsupportedOperationException();
  67   }
  68
  69   public Iterator<File> iterator() {
  70     return this;
  71   }
  72 }