From 0beba6cafae63f9b6ed605fd8b9aa20f6ca67738 Mon Sep 17 00:00:00 2001
From: Eric Scharff <scharff@sharedmind.readytalk.com>
Date: Wed, 26 Sep 2007 09:48:59 -0600
Subject: [PATCH] ArrayList now implements ListIterator (for reverse traversals
 of lists)

---
 classpath/java/util/ArrayList.java    |  4 ++++
 classpath/java/util/Collections.java  | 22 ++++++++++++++++++++--
 classpath/java/util/ListIterator.java |  6 ++++++
 3 files changed, 30 insertions(+), 2 deletions(-)
 create mode 100644 classpath/java/util/ListIterator.java

diff --git a/classpath/java/util/ArrayList.java b/classpath/java/util/ArrayList.java
index 3589f648ca..c069cb116a 100644
--- a/classpath/java/util/ArrayList.java
+++ b/classpath/java/util/ArrayList.java
@@ -154,4 +154,8 @@ public class ArrayList<T> implements List<T> {
   public Iterator<T> iterator() {
     return new Collections.ArrayListIterator(this);
   }
+
+  public ListIterator<T> listIterator(int index) {
+    return new Collections.ArrayListIterator(this, index);
+  }
 }
diff --git a/classpath/java/util/Collections.java b/classpath/java/util/Collections.java
index 732df1f706..bbc4e60b3f 100644
--- a/classpath/java/util/Collections.java
+++ b/classpath/java/util/Collections.java
@@ -102,13 +102,31 @@ public class Collections {
     }
   }
 
-  static class ArrayListIterator<T> implements Iterator<T> {
+  static class ArrayListIterator<T> implements ListIterator<T> {
     private final List<T> list;
     private boolean canRemove = false;
-    private int index = -1;
+    private int index;
 
     public ArrayListIterator(List<T> list) {
+      this(list, 0);
+    }
+
+    public ArrayListIterator(List<T> list, int index) {
       this.list = list;
+      this.index = index - 1;
+    }
+
+    public boolean hasPrevious() {
+      return index >= 0;
+    }
+
+    public T previous() {
+      if (hasPrevious()) {
+        canRemove = true;
+        return list.get(index--);
+      } else {
+        throw new NoSuchElementException();
+      }
     }
 
     public T next() {
diff --git a/classpath/java/util/ListIterator.java b/classpath/java/util/ListIterator.java
new file mode 100644
index 0000000000..126a00b716
--- /dev/null
+++ b/classpath/java/util/ListIterator.java
@@ -0,0 +1,6 @@
+package java.util;
+
+public interface ListIterator<E> extends Iterator<E> {
+  public boolean hasPrevious();
+  public E previous();
+}