add AbstractList and AbstractSequentialList classes to java.util and listIterator methods to java.util.List

classpath/java/util/AbstractList.java

@@ -0,0 +1,15 @@
+/* Copyright (c) 2009, Avian Contributors
+
+   Permission to use, copy, modify, and/or distribute this software
+   for any purpose with or without fee is hereby granted, provided
+   that the above copyright notice and this permission notice appear
+   in all copies.
+
+   There is NO WARRANTY for this software.  See license.txt for
+   details. */
+
+package java.util;
+
+public abstract class AbstractList<T> extends AbstractCollection<T>
+  implements List<T>
+{ }

classpath/java/util/AbstractSequentialList.java

@@ -0,0 +1,15 @@
+/* Copyright (c) 2009, Avian Contributors
+
+   Permission to use, copy, modify, and/or distribute this software
+   for any purpose with or without fee is hereby granted, provided
+   that the above copyright notice and this permission notice appear
+   in all copies.
+
+   There is NO WARRANTY for this software.  See license.txt for
+   details. */
+
+package java.util;
+
+public abstract class AbstractSequentialList<T> extends AbstractList<T>
+  implements List<T>
+{ }

classpath/java/util/ArrayList.java

@@ -10,7 +10,7 @@
 
 package java.util;
 
-public class ArrayList<T> implements List<T> {
+public class ArrayList<T> extends AbstractList<T> {
   private static final int MinimumCapacity = 16;
 
   private Object[] array;
@@ -169,7 +169,7 @@ public class ArrayList<T> implements List<T> {
   }
 
   public Iterator<T> iterator() {
-    return new Collections.ArrayListIterator(this);
+    return listIterator();
   }
 
   public ListIterator<T> listIterator(int index) {

classpath/java/util/Arrays.java

@@ -102,7 +102,15 @@ public class Arrays {
       }
 
       public Iterator<T> iterator() {
-        return new Collections.ArrayListIterator(this);
+        return listIterator();
+      }
+
+      public ListIterator<T> listIterator(int index) {
+        return new Collections.ArrayListIterator(this, index);
+      }
+
+      public ListIterator<T> listIterator() {
+        return listIterator(0);
       }
     };
   }

classpath/java/util/Collections.java

@@ -198,7 +198,6 @@ public class Collections {
     return new SynchronizedMap<K, V> (map); 
   }
   
-
   static class SynchronizedSet<T>
     extends SynchronizedCollection<T>
     implements Set<T>
@@ -232,7 +231,7 @@ public class Collections {
 
   static class ArrayListIterator<T> implements ListIterator<T> {
     private final List<T> list;
-    private boolean canRemove = false;
+    private int toRemove = -1;
     private int index;
 
     public ArrayListIterator(List<T> list) {
@@ -250,7 +249,7 @@ public class Collections {
 
     public T previous() {
       if (hasPrevious()) {
-        canRemove = true;
+        toRemove = index;
         return list.get(index--);
       } else {
         throw new NoSuchElementException();
@@ -259,8 +258,8 @@ public class Collections {
 
     public T next() {
       if (hasNext()) {
-        canRemove = true;
-        return list.get(++index);
+        toRemove = ++index;
+        return list.get(index);
       } else {
         throw new NoSuchElementException();
       }
@@ -271,9 +270,10 @@ public class Collections {
     }
 
     public void remove() {
-      if (canRemove) {
-        canRemove = false;
-        list.remove(index--);
+      if (toRemove != -1) {
+        list.remove(toRemove);
+        index = toRemove - 1;
+        toRemove = -1;
       } else {
         throw new IllegalStateException();
       }

classpath/java/util/LinkedList.java

@@ -10,7 +10,7 @@
 
 package java.util;
 
-public class LinkedList<T> implements List<T> {
+public class LinkedList<T> extends AbstractSequentialList<T> {
   private Cell<T> front;
   private Cell<T> rear;
   private int size;
@@ -198,7 +198,19 @@ public class LinkedList<T> implements List<T> {
   }
 
   public Iterator<T> iterator() {
-    return new MyIterator(front);
+    return listIterator();
+  }
+
+  public ListIterator<T> listIterator(int index) {
+    MyIterator it = new MyIterator();
+    for (int i = 0; i < index; ++i) {
+      it.next();
+    }
+    return it;
+  }
+
+  public ListIterator<T> listIterator() {
+    return listIterator(0);
   }
 
   public String toString() {
@@ -217,18 +229,29 @@ public class LinkedList<T> implements List<T> {
     }
   }
 
-  private class MyIterator implements Iterator<T> {
+  private class MyIterator implements ListIterator<T> {
+    private Cell<T> toRemove;
     private Cell<T> current;
-    private Cell<T> next;
 
-    public MyIterator(Cell<T> start) {
-      next = start;
+    public T previous() {
+      if (hasPrevious()) {
+        T v = current.value;
+        toRemove = current;
+        current = current.prev;
+        return v;
+      } else {
+        throw new NoSuchElementException();
+      }
     }
 
     public T next() {
       if (hasNext()) {
-        current = next;
-        next = next.next;
+        if (current == null) {
+          current = front;
+        } else {
+          current = current.next;
+        }
+        toRemove = current;
         return current.value;
       } else {
         throw new NoSuchElementException();
@@ -236,13 +259,22 @@ public class LinkedList<T> implements List<T> {
     }
 
     public boolean hasNext() {
-      return next != null;
+      if (current == null) {
+        return front != null;
+      } else {
+        return current.next != null;
+      }
+    }
+
+    public boolean hasPrevious() {
+      return current != null;
     }
 
     public void remove() {
-      if (current != null) {
-        LinkedList.this.remove(current);
-        current = null;
+      if (toRemove != null) {
+        current = toRemove.prev;
+        LinkedList.this.remove(toRemove);
+        toRemove = null;
       } else {
         throw new IllegalStateException();
       }

classpath/java/util/List.java

@@ -22,4 +22,8 @@ public interface List<T> extends Collection<T> {
   public void add(int index, T element);
 
   public boolean isEmpty();
+
+  public ListIterator<T> listIterator(int index);
+
+  public ListIterator<T> listIterator();
 }

classpath/java/util/Vector.java

@@ -10,7 +10,7 @@
 
 package java.util;
 
-public class Vector<T> implements List<T> {
+public class Vector<T> extends AbstractList<T> {
   private final ArrayList<T> list;
 
   public Vector(int capacity) {
@@ -112,7 +112,15 @@ public class Vector<T> implements List<T> {
   }
 
   public Iterator<T> iterator() {
-    return new Collections.ArrayListIterator(this);
+    return listIterator();
+  }
+
+  public ListIterator<T> listIterator(int index) {
+    return new Collections.ArrayListIterator(this, index);
+  }
+
+  public ListIterator<T> listIterator() {
+    return listIterator(0);
   }
 
   public Enumeration<T> elements() {

test/List.java

@@ -1,4 +1,6 @@
 import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.ListIterator;
 
 public class List {
   private static void expect(boolean v) {
@@ -21,6 +23,114 @@ public class List {
     expect(s1.equals(s2));
   }
 
+  private static void testIterators(java.util.List<Integer> l) {
+    l.add(1);
+    l.add(2);
+    l.add(3);
+    
+    ListIterator<Integer> it = l.listIterator();
+    expect(it.next().equals(Integer.valueOf(1)));
+    expect(it.next().equals(Integer.valueOf(2)));
+    expect(it.next().equals(Integer.valueOf(3)));
+    expect(! it.hasNext());
+
+    it = l.listIterator(1);
+    expect(it.next().equals(Integer.valueOf(2)));
+    expect(it.next().equals(Integer.valueOf(3)));
+    expect(! it.hasNext());
+
+    it = l.listIterator(2);
+    expect(it.next().equals(Integer.valueOf(3)));
+    expect(! it.hasNext());
+
+    it = l.listIterator(3);
+    expect(it.previous().equals(Integer.valueOf(3)));
+    expect(it.previous().equals(Integer.valueOf(2)));
+    expect(it.previous().equals(Integer.valueOf(1)));
+    expect(! it.hasPrevious());
+
+    it = l.listIterator(2);
+    expect(it.previous().equals(Integer.valueOf(2)));
+    expect(it.previous().equals(Integer.valueOf(1)));
+    expect(! it.hasPrevious());
+
+    it = l.listIterator(1);
+    expect(it.previous().equals(Integer.valueOf(1)));
+    expect(! it.hasPrevious());
+  }
+
+  private static void testIterators2(java.util.List<Integer> l) {
+    l.add(1);
+    l.add(2);
+    l.add(3);
+    
+    ListIterator<Integer> it = l.listIterator();
+    expect(it.next().equals(Integer.valueOf(1)));
+    it.remove();
+    expect(it.next().equals(Integer.valueOf(2)));
+    it.remove();
+    expect(it.next().equals(Integer.valueOf(3)));
+    it.remove();
+    expect(! it.hasNext());
+    expect(l.isEmpty());
+
+    l.add(1);
+    l.add(2);
+    l.add(3);
+    
+    it = l.listIterator(1);
+    expect(it.next().equals(Integer.valueOf(2)));
+    it.remove();
+    expect(it.next().equals(Integer.valueOf(3)));
+    it.remove();
+    expect(! it.hasNext());
+    expect(l.size() == 1);
+
+    l.add(2);
+    l.add(3);
+
+    it = l.listIterator(2);
+    expect(it.next().equals(Integer.valueOf(3)));
+    it.remove();
+    expect(! it.hasNext());
+    expect(l.size() == 2);
+
+    l.add(3);
+
+    it = l.listIterator(3);
+    expect(it.previous().equals(Integer.valueOf(3)));
+    it.remove();
+    expect(it.previous().equals(Integer.valueOf(2)));
+    it.remove();
+    expect(it.previous().equals(Integer.valueOf(1)));
+    it.remove();
+    expect(! it.hasPrevious());
+    expect(l.isEmpty());
+
+    l.add(1);
+    l.add(2);
+    l.add(3);
+
+    it = l.listIterator(2);
+    expect(it.previous().equals(Integer.valueOf(2)));
+    it.remove();
+    expect(it.previous().equals(Integer.valueOf(1)));
+    it.remove();
+    expect(! it.hasPrevious());
+    expect(l.size() == 1);
+
+    l.clear();
+    l.add(1);
+    l.add(2);
+    l.add(3);
+
+    it = l.listIterator(1);
+    expect(it.previous().equals(Integer.valueOf(1)));
+    it.remove();
+    expect(! it.hasPrevious());
+    expect(l.size() == 2);
+  }
+
   public static void main(String args[]) {
     ArrayList<Integer> l = new ArrayList<Integer>();
     l.add(1); l.add(2); l.add(3); l.add(4); l.add(5);
@@ -39,5 +149,11 @@ public class List {
     for (int i=0; i < z.length; i++) {
       System.out.println(z[i]);
     }
+
+    testIterators(new ArrayList());
+    testIterators(new LinkedList());
+
+    testIterators2(new ArrayList());
+    testIterators2(new LinkedList());
   }
 }