--- jsr166/src/jsr166e/extra/ReadMostlyVector.java	2011/07/16 14:56:30	1.3
+++ jsr166/src/jsr166e/extra/ReadMostlyVector.java	2011/12/31 05:38:24	1.17
@@ -19,7 +19,10 @@ import java.util.*;
  * best-effort in the presence of concurrent modifications, and do
  * <em>NOT</em> throw {@link ConcurrentModificationException}.  An
  * iterator's {@code next()} method returns consecutive elements as
- * they appear in the underlying array upon each access.
+ * they appear in the underlying array upon each access. Alternatively,
+ * method {@link #snapshotIterator} may be used for deterministic
+ * traversals, at the expense of making a copy, and unavailability of
+ * method {@code Iterator.remove}.
  *
  * <p>Otherwise, this class supports all methods, under the same
  * documented specifications, as {@code Vector}.  Consult {@link
@@ -29,7 +32,8 @@ import java.util.*;
  *
  * @author Doug Lea
  */
-public class ReadMostlyVector<E> implements List<E>, RandomAccess, Cloneable, java.io.Serializable {
+public class ReadMostlyVector<E>
+        implements List<E>, RandomAccess, Cloneable, java.io.Serializable {
     private static final long serialVersionUID = 8673264195747942595L;
 
     /*
@@ -54,9 +58,9 @@ public class ReadMostlyVector<E> impleme
     private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
 
     // fields are non-private to simpify nested class access
-    Object[] array;
+    volatile Object[] array;
     final SequenceLock lock;
-    int count;
+    volatile int count;
     final int capacityIncrement;
 
     /**
@@ -126,7 +130,7 @@ public class ReadMostlyVector<E> impleme
     }
 
     // For explanation, see CopyOnWriteArrayList
-    final void grow(int minCapacity) {
+    final Object[] grow(int minCapacity) {
         int oldCapacity = array.length;
         int newCapacity = oldCapacity + ((capacityIncrement > 0) ?
                                          capacityIncrement : oldCapacity);
@@ -134,7 +138,7 @@ public class ReadMostlyVector<E> impleme
             newCapacity = minCapacity;
         if (newCapacity - MAX_ARRAY_SIZE > 0)
             newCapacity = hugeCapacity(minCapacity);
-        array = Arrays.copyOf(array, newCapacity);
+        return array = Arrays.copyOf(array, newCapacity);
     }
 
     static int hugeCapacity(int minCapacity) {
@@ -151,13 +155,14 @@ public class ReadMostlyVector<E> impleme
      * as well as sublist and iterator classes.
      */
 
+    // Version of indexOf that returns -1 if either not present or invalid
     final int validatedIndexOf(Object x, Object[] items, int index, int fence,
                                long seq) {
         for (int i = index; i < fence; ++i) {
             Object e = items[i];
             if (lock.getSequence() != seq)
                 break;
-            if ((x == null) ? e == null : (e != null && x.equals(e)))
+            if ((x == null) ? e == null : x.equals(e))
                 return i;
         }
         return -1;
@@ -167,7 +172,7 @@ public class ReadMostlyVector<E> impleme
         Object[] items = array;
         for (int i = index; i < fence; ++i) {
             Object e = items[i];
-            if ((x == null) ? e == null : (e != null && x.equals(e)))
+            if ((x == null) ? e == null : x.equals(e))
                 return i;
         }
         return -1;
@@ -179,7 +184,7 @@ public class ReadMostlyVector<E> impleme
             Object e = items[i];
             if (lock.getSequence() != seq)
                 break;
-            if ((x == null) ? e == null : (e != null && x.equals(e)))
+            if ((x == null) ? e == null : x.equals(e))
                 return i;
         }
         return -1;
@@ -189,58 +194,62 @@ public class ReadMostlyVector<E> impleme
         Object[] items = array;
         for (int i = index; i >= origin; --i) {
             Object e = items[i];
-            if ((x == null) ? e == null : (e != null && x.equals(e)))
+            if ((x == null) ? e == null : x.equals(e))
                 return i;
         }
         return -1;
     }
 
-    final void internalAdd(Object e) {
+    final void rawAdd(E e) {
         int n = count;
-        if (n >= array.length)
-            grow(n + 1);
-        array[n] = e;
+        Object[] items = array;
+        if (n >= items.length)
+            items = grow(n + 1);
+        items[n] = e;
         count = n + 1;
     }
 
-    final void internalAddAt(int index, Object e) {
+    final void rawAddAt(int index, E e) {
         int n = count;
+        Object[] items = array;
         if (index > n)
             throw new ArrayIndexOutOfBoundsException(index);
-        if (n >= array.length)
-            grow(n + 1);
+        if (n >= items.length)
+            items = grow(n + 1);
         if (index < n)
-            System.arraycopy(array, index, array, index + 1, n - index);
-        array[index] = e;
+            System.arraycopy(items, index, items, index + 1, n - index);
+        items[index] = e;
         count = n + 1;
     }
 
-    final boolean internalAddAllAt(int index, Object[] elements) {
+    final boolean rawAddAllAt(int index, Object[] elements) {
         int n = count;
+        Object[] items = array;
         if (index < 0 || index > n)
             throw new ArrayIndexOutOfBoundsException(index);
         int len = elements.length;
         if (len == 0)
             return false;
         int newCount = n + len;
-        if (newCount >= array.length)
-            grow(newCount);
-        int mv = count - index;
+        if (newCount >= items.length)
+            items = grow(newCount);
+        int mv = n - index;
         if (mv > 0)
-            System.arraycopy(array, index, array, index + len, mv);
-        System.arraycopy(elements, 0, array, index, len);
+            System.arraycopy(items, index, items, index + len, mv);
+        System.arraycopy(elements, 0, items, index, len);
         count = newCount;
         return true;
     }
 
-    final boolean internalRemoveAt(int index) {
+    final boolean rawRemoveAt(int index) {
         int n = count - 1;
+        Object[] items = array;
         if (index < 0 || index > n)
             return false;
         int mv = n - index;
         if (mv > 0)
-            System.arraycopy(array, index + 1, array, index, mv);
-        array[n] = null;
+            System.arraycopy(items, index + 1, items, index, mv);
+        items[n] = null;
         count = n;
         return true;
     }
@@ -253,7 +262,7 @@ public class ReadMostlyVector<E> impleme
      * field under lock.
      */
     final boolean internalRemoveAll(Collection<?> c, int origin, int bound) {
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         boolean removed = false;
         lock.lock();
         try {
@@ -261,7 +270,7 @@ public class ReadMostlyVector<E> impleme
             int fence = bound < 0 || bound > n ? n : bound;
             if (origin >= 0 && origin < fence) {
                 for (Object x : c) {
-                    while (internalRemoveAt(rawIndexOf(x, origin, fence)))
+                    while (rawRemoveAt(rawIndexOf(x, origin, fence)))
                         removed = true;
                 }
             }
@@ -272,25 +281,29 @@ public class ReadMostlyVector<E> impleme
     }
 
     final boolean internalRetainAll(Collection<?> c, int origin, int bound) {
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         boolean removed = false;
         if (c != this) {
             lock.lock();
             try {
+                Object[] items = array;
                 int i = origin;
                 int n = count;
                 int fence = bound < 0 || bound > n ? n : bound;
-                while (i < fence) {
-                    if (c.contains(array[i]))
+                while (i >= 0 && i < fence) {
+                    if (c.contains(items[i]))
                         ++i;
                     else {
                         --fence;
-                        int mv = --count - i;
+                        int mv = --n - i;
                         if (mv > 0)
-                            System.arraycopy(array, i + 1, array, i, mv);
-                        removed = true;
+                            System.arraycopy(items, i + 1, items, i, mv);
                     }
                 }
+                if (count != n) {
+                    count = n;
+                    removed = true;
+                }
             } finally {
                 lock.unlock();
             }
@@ -302,27 +315,28 @@ public class ReadMostlyVector<E> impleme
         int n = count;
         int fence = bound < 0 || bound > n ? n : bound;
         if (origin >= 0 && origin < fence) {
+            Object[] items = array;
             int removed = fence - origin;
             int newCount = n - removed;
             int mv = n - (origin + removed);
             if (mv > 0)
-                System.arraycopy(array, origin + removed, array, origin, mv);
+                System.arraycopy(items, origin + removed, items, origin, mv);
             for (int i = n; i < newCount; ++i)
-                array[i] = null;
+                items[i] = null;
             count = newCount;
         }
     }
 
     final boolean internalContainsAll(Collection<?> c, int origin, int bound) {
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         boolean contained;
         boolean locked = false;
         try {
             for (;;) {
                 long seq = lock.awaitAvailability();
+                int n = count;
                 Object[] items = array;
                 int len = items.length;
-                int n = count;
                 if (n > len)
                     continue;
                 int fence = bound < 0 || bound > n ? n : bound;
@@ -331,7 +345,11 @@ public class ReadMostlyVector<E> impleme
                 else {
                     contained = true;
                     for (Object e : c) {
-                        if (validatedIndexOf(e, items, origin, fence, seq) < 0) {
+                        int idx = (locked ?
+                                   rawIndexOf(e, origin, fence) :
+                                   validatedIndexOf(e, items, origin,
+                                                    fence, seq));
+                        if (idx < 0) {
                             contained = false;
                             break;
                         }
@@ -350,33 +368,27 @@ public class ReadMostlyVector<E> impleme
     }
 
     final boolean internalEquals(List<?> list, int origin, int bound) {
-        SequenceLock lock = this.lock;
-        boolean equal;
+        final SequenceLock lock = this.lock;
         boolean locked = false;
+        boolean equal;
         try {
-            outer:for (;;) {
-                equal = true;
+            for (;;) {
                 long seq = lock.awaitAvailability();
                 Object[] items = array;
-                int len = items.length;
                 int n = count;
-                if (n > len)
-                    continue;
-                int fence = bound < 0 || bound > n ? n : bound;
-                if (origin < 0)
+                if (n > items.length || origin < 0)
                     equal = false;
                 else {
+                    equal = true;
+                    int fence = bound < 0 || bound > n ? n : bound;
                     Iterator<?> it = list.iterator();
                     for (int i = origin; i < fence; ++i) {
-                        if (!it.hasNext()) {
-                            equal = false;
-                            break;
-                        }
-                        Object x = it.next();
-                        Object y = items[i];
-                        if (lock.getSequence() != seq)
-                            continue outer;
-                        if ((x == null) ? y != null : (y == null || !x.equals(y))) {
+                        Object x = items[i];
+                        Object y;
+                        if ((!locked && lock.getSequence() != seq) ||
+                            !it.hasNext() ||
+                            (y = it.next()) == null ?
+                            x != null : !y.equals(x)) {
                             equal = false;
                             break;
                         }
@@ -397,7 +409,7 @@ public class ReadMostlyVector<E> impleme
     }
 
     final int internalHashCode(int origin, int bound) {
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         int hash;
         boolean locked = false;
         try {
@@ -405,8 +417,8 @@ public class ReadMostlyVector<E> impleme
                 hash = 1;
                 long seq = lock.awaitAvailability();
                 Object[] items = array;
-                int len = items.length;
                 int n = count;
+                int len = items.length;
                 if (n > len)
                     continue;
                 int fence = bound < 0 || bound > n ? n : bound;
@@ -429,15 +441,15 @@ public class ReadMostlyVector<E> impleme
     }
 
     final String internalToString(int origin, int bound) {
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         String ret;
         boolean locked = false;
         try {
             outer:for (;;) {
                 long seq = lock.awaitAvailability();
                 Object[] items = array;
-                int len = items.length;
                 int n = count;
+                int len = items.length;
                 if (n > len)
                     continue;
                 int fence = bound < 0 || bound > n ? n : bound;
@@ -450,7 +462,7 @@ public class ReadMostlyVector<E> impleme
                         Object e = items[i];
                         if (e == this)
                             sb.append("(this Collection)");
-                        else if (lock.getSequence() != seq)
+                        else if (!locked && lock.getSequence() != seq)
                             continue outer;
                         else
                             sb.append(e.toString());
@@ -476,15 +488,15 @@ public class ReadMostlyVector<E> impleme
 
     final Object[] internalToArray(int origin, int bound) {
         Object[] result;
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         boolean locked = false;
         try {
             for (;;) {
                 result = null;
                 long seq = lock.awaitAvailability();
                 Object[] items = array;
-                int len = items.length;
                 int n = count;
+                int len = items.length;
                 if (n > len)
                     continue;
                 int fence = bound < 0 || bound > n ? n : bound;
@@ -503,32 +515,33 @@ public class ReadMostlyVector<E> impleme
         return result;
     }
 
+    @SuppressWarnings("unchecked")
     final <T> T[] internalToArray(T[] a, int origin, int bound) {
         int alen = a.length;
         T[] result;
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         boolean locked = false;
         try {
             for (;;) {
                 long seq = lock.awaitAvailability();
                 Object[] items = array;
-                int len = items.length;
                 int n = count;
+                int len = items.length;
                 if (n > len)
                     continue;
                 int fence = bound < 0 || bound > n ? n : bound;
                 int rlen = fence - origin;
+                if (rlen < 0)
+                    rlen = 0;
                 if (origin < 0 || alen >= rlen) {
-                    if (rlen < 0)
-                        rlen = 0;
-                    else if (rlen > 0)
-                        System.arraycopy(array, 0, a, origin, rlen);
+                    if (rlen > 0)
+                        System.arraycopy(items, 0, a, origin, rlen);
                     if (alen > rlen)
                         a[rlen] = null;
                     result = a;
                 }
                 else
-                    result = (T[]) Arrays.copyOfRange(array, origin,
+                    result = (T[]) Arrays.copyOfRange(items, origin,
                                                       fence, a.getClass());
                 if (lock.getSequence() == seq)
                     break;
@@ -545,10 +558,10 @@ public class ReadMostlyVector<E> impleme
     // public List methods
 
     public boolean add(E e) {
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         lock.lock();
         try {
-            internalAdd(e);
+            rawAdd(e);
         } finally {
             lock.unlock();
         }
@@ -556,10 +569,10 @@ public class ReadMostlyVector<E> impleme
     }
 
     public void add(int index, E element) {
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         lock.lock();
         try {
-            internalAddAt(index, element);
+            rawAddAt(index, element);
         } finally {
             lock.unlock();
         }
@@ -570,13 +583,15 @@ public class ReadMostlyVector<E> impleme
         int len = elements.length;
         if (len == 0)
             return false;
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         lock.lock();
         try {
-            int newCount = count + len;
-            if (newCount >= array.length)
-                grow(newCount);
-            System.arraycopy(elements, 0, array, count, len);
+            Object[] items = array;
+            int n = count;
+            int newCount = n + len;
+            if (newCount >= items.length)
+                items = grow(newCount);
+            System.arraycopy(elements, 0, items, n, len);
             count = newCount;
         } finally {
             lock.unlock();
@@ -585,12 +600,12 @@ public class ReadMostlyVector<E> impleme
     }
 
     public boolean addAll(int index, Collection<? extends E> c) {
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         boolean ret;
         Object[] elements = c.toArray();
         lock.lock();
         try {
-            ret = internalAddAllAt(index, elements);
+            ret = rawAddAllAt(index, elements);
         } finally {
             lock.unlock();
         }
@@ -598,11 +613,13 @@ public class ReadMostlyVector<E> impleme
     }
 
     public void clear() {
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         lock.lock();
         try {
-            for (int i = 0; i < count; i++)
-                array[i] = null;
+            int n = count;
+            Object[] items = array;
+            for (int i = 0; i < n; i++)
+                items[i] = null;
             count = 0;
         } finally {
             lock.unlock();
@@ -622,31 +639,25 @@ public class ReadMostlyVector<E> impleme
             return true;
         if (!(o instanceof List))
             return false;
-        return internalEquals((List<?>)(o), 0, -1);
+        return internalEquals((List<?>)o, 0, -1);
     }
 
     public E get(int index) {
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         for (;;) {
             long seq = lock.awaitAvailability();
-            Object[] items = array;
             int n = count;
+            Object[] items = array;
             if (n > items.length)
                 continue;
-            Object e; boolean ex;
-            if (index < 0 || index >= n) {
-                e = null;
-                ex = true;
-            }
-            else {
-                e = items[index];
-                ex = false;
-            }
+            boolean outOfBounds = (index < 0 || index >= n);
+            @SuppressWarnings("unchecked")
+            E e = outOfBounds ? null : (E) items[index];
             if (lock.getSequence() == seq) {
-                if (ex)
+                if (outOfBounds)
                     throw new ArrayIndexOutOfBoundsException(index);
                 else
-                    return (E)e;
+                    return e;
             }
         }
     }
@@ -656,83 +667,73 @@ public class ReadMostlyVector<E> impleme
     }
 
     public int indexOf(Object o) {
-        SequenceLock lock = this.lock;
-        long seq = lock.awaitAvailability();
-        Object[] items = array;
-        int n = count;
-        if (n <= items.length) {
-            int idx = validatedIndexOf(o, items, 0, n, seq);
-            if (lock.getSequence() == seq)
-                return idx;
-        }
-        lock.lock();
-        try {
-            return rawIndexOf(o, 0, count);
-        } finally {
-            lock.unlock();
-        }
+        return indexOf(o, 0);
     }
 
     public boolean isEmpty() {
-        long ignore = lock.getSequence();
         return count == 0;
     }
 
     public Iterator<E> iterator() {
-        return new Itr(this, 0);
+        return new Itr<E>(this, 0);
     }
 
     public int lastIndexOf(Object o) {
-        SequenceLock lock = this.lock;
-        long seq = lock.awaitAvailability();
-        Object[] items = array;
-        int n = count;
-        if (n <= items.length) {
-            int idx = validatedLastIndexOf(o, items, n - 1, 0, seq);
-            if (lock.getSequence() == seq)
-                return idx;
-        }
-        lock.lock();
-        try {
-            return rawLastIndexOf(o, count - 1, 0);
-        } finally {
-            lock.unlock();
+        final SequenceLock lock = this.lock;
+        for (;;) {
+            long seq = lock.awaitAvailability();
+            Object[] items = array;
+            int n = count;
+            if (n <= items.length) {
+                for (int i = n - 1; i >= 0; --i) {
+                    Object e = items[i];
+                    if (lock.getSequence() != seq) {
+                        lock.lock();
+                        try {
+                            return rawLastIndexOf(o, 0, count);
+                        } finally {
+                            lock.unlock();
+                        }
+                    }
+                    else if ((o == null) ? e == null : o.equals(e))
+                        return i;
+                }
+                return -1;
+            }
         }
     }
 
     public ListIterator<E> listIterator() {
-        return new Itr(this, 0);
+        return new Itr<E>(this, 0);
     }
 
     public ListIterator<E> listIterator(int index) {
-        return new Itr(this, index);
+        return new Itr<E>(this, index);
     }
 
     public E remove(int index) {
-        SequenceLock lock = this.lock;
-        Object oldValue;
+        final SequenceLock lock = this.lock;
         lock.lock();
         try {
             if (index < 0 || index >= count)
                 throw new ArrayIndexOutOfBoundsException(index);
-            oldValue = array[index];
-            internalRemoveAt(index);
+            @SuppressWarnings("unchecked")
+            E oldValue = (E) array[index];
+            rawRemoveAt(index);
+            return oldValue;
         } finally {
             lock.unlock();
         }
-        return (E)oldValue;
     }
 
     public boolean remove(Object o) {
-        SequenceLock lock = this.lock;
-        boolean removed;
+        final SequenceLock lock = this.lock;
         lock.lock();
         try {
-            removed = internalRemoveAt(rawIndexOf(o, 0, count));
+            return rawRemoveAt(rawIndexOf(o, 0, count));
         } finally {
             lock.unlock();
         }
-        return removed;
     }
 
     public boolean removeAll(Collection<?> c) {
@@ -744,22 +745,22 @@ public class ReadMostlyVector<E> impleme
     }
 
     public E set(int index, E element) {
-        Object oldValue;
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         lock.lock();
         try {
+            Object[] items = array;
             if (index < 0 || index >= count)
                 throw new ArrayIndexOutOfBoundsException(index);
-            oldValue = array[index];
-            array[index] = element;
+            @SuppressWarnings("unchecked")
+            E oldValue = (E) items[index];
+            items[index] = element;
+            return oldValue;
         } finally {
             lock.unlock();
         }
-        return (E)oldValue;
     }
 
     public int size() {
-        long ignore = lock.getSequence();
         return count;
     }
 
@@ -768,7 +769,7 @@ public class ReadMostlyVector<E> impleme
         int ssize = toIndex - fromIndex;
         if (fromIndex < 0 || toIndex > c || ssize < 0)
             throw new IndexOutOfBoundsException();
-        return new ReadMostlyVectorSublist(this, fromIndex, ssize);
+        return new ReadMostlyVectorSublist<E>(this, fromIndex, ssize);
     }
 
     public Object[] toArray() {
@@ -789,23 +790,21 @@ public class ReadMostlyVector<E> impleme
      * Append the element if not present.
      *
      * @param e element to be added to this list, if absent
-     * @return <tt>true</tt> if the element was added
+     * @return {@code true} if the element was added
      */
     public boolean addIfAbsent(E e) {
-        boolean added;
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         lock.lock();
         try {
             if (rawIndexOf(e, 0, count) < 0) {
-                internalAdd(e);
-                added = true;
+                rawAdd(e);
+                return true;
             }
             else
-                added = false;
+                return false;
         } finally {
             lock.unlock();
         }
-        return added;
     }
 
     /**
@@ -827,9 +826,10 @@ public class ReadMostlyVector<E> impleme
             lock.lock();
             try {
                 for (int i = 0; i < clen; ++i) {
-                    Object e = cs[i];
+                    @SuppressWarnings("unchecked")
+                    E e = (E) cs[i];
                     if (rawIndexOf(e, 0, count) < 0) {
-                        internalAdd(e);
+                        rawAdd(e);
                         ++added;
                     }
                 }
@@ -840,11 +840,37 @@ public class ReadMostlyVector<E> impleme
         return added;
     }
 
+    /**
+     * Returns an iterator operating over a snapshot copy of the
+     * elements of this collection created upon construction of the
+     * iterator. The iterator does <em>NOT</em> support the
+     * {@code remove} method.
+     *
+     * @return an iterator over the elements in this list in proper sequence
+     */
+    public Iterator<E> snapshotIterator() {
+        return new SnapshotIterator<E>(this);
+    }
+
+    static final class SnapshotIterator<E> implements Iterator<E> {
+        private final Object[] items;
+        private int cursor;
+        SnapshotIterator(ReadMostlyVector<E> v) { items = v.toArray(); }
+        public boolean hasNext() { return cursor < items.length; }
+        @SuppressWarnings("unchecked")
+        public E next() {
+            if (cursor < items.length)
+                return (E) items[cursor++];
+            throw new NoSuchElementException();
+        }
+        public void remove() { throw new UnsupportedOperationException() ; }
+    }
+
     // Vector-only methods
 
     /** See {@link Vector#firstElement} */
     public E firstElement() {
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         for (;;) {
             long seq = lock.awaitAvailability();
             Object[] items = array;
@@ -852,27 +878,21 @@ public class ReadMostlyVector<E> impleme
             int n = count;
             if (n > len)
                 continue;
-            Object e; boolean ex;
-            if (n > 0) {
-                e = items[0];
-                ex = false;
-            }
-            else {
-                e = null;
-                ex = true;
-            }
+            boolean empty = (n == 0);
+            @SuppressWarnings("unchecked")
+            E e = empty ? null : (E) items[0];
             if (lock.getSequence() == seq) {
-                if (ex)
+                if (empty)
                     throw new NoSuchElementException();
                 else
-                    return (E)e;
+                    return e;
             }
         }
     }
 
     /** See {@link Vector#lastElement} */
     public E lastElement() {
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         for (;;) {
             long seq = lock.awaitAvailability();
             Object[] items = array;
@@ -880,27 +900,21 @@ public class ReadMostlyVector<E> impleme
             int n = count;
             if (n > len)
                 continue;
-            Object e; boolean ex;
-            if (n > 0) {
-                e = items[n - 1];
-                ex = false;
-            }
-            else {
-                e = null;
-                ex = true;
-            }
+            boolean empty = (n == 0);
+            @SuppressWarnings("unchecked")
+            E e = empty ? null : (E) items[n - 1];
             if (lock.getSequence() == seq) {
-                if (ex)
+                if (empty)
                     throw new NoSuchElementException();
                 else
-                    return (E)e;
+                    return e;
             }
         }
     }
 
     /** See {@link Vector#indexOf(Object, int)} */
     public int indexOf(Object o, int index) {
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         int idx = 0;
         boolean ex = false;
         long seq = lock.awaitAvailability();
@@ -919,7 +933,7 @@ public class ReadMostlyVector<E> impleme
                 if (index < 0)
                     ex = true;
                 else
-                    idx = rawIndexOf(o, 0, count);
+                    idx = rawIndexOf(o, index, count);
             } finally {
                 lock.unlock();
             }
@@ -931,7 +945,7 @@ public class ReadMostlyVector<E> impleme
 
     /** See {@link Vector#lastIndexOf(Object, int)} */
     public int lastIndexOf(Object o, int index) {
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         int idx = 0;
         boolean ex = false;
         long seq = lock.awaitAvailability();
@@ -964,15 +978,16 @@ public class ReadMostlyVector<E> impleme
     public void setSize(int newSize) {
         if (newSize < 0)
             throw new ArrayIndexOutOfBoundsException(newSize);
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         lock.lock();
         try {
             int n = count;
             if (newSize > n)
                 grow(newSize);
             else {
+                Object[] items = array;
                 for (int i = newSize ; i < n ; i++)
-                    array[i] = null;
+                    items[i] = null;
             }
             count = newSize;
         } finally {
@@ -982,7 +997,7 @@ public class ReadMostlyVector<E> impleme
 
     /** See {@link Vector#copyInto} */
     public void copyInto(Object[] anArray) {
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         lock.lock();
         try {
             System.arraycopy(array, 0, anArray, 0, count);
@@ -993,11 +1008,13 @@ public class ReadMostlyVector<E> impleme
 
     /** See {@link Vector#trimToSize} */
     public void trimToSize() {
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         lock.lock();
         try {
-            if (count < array.length)
-                array = Arrays.copyOf(array, count);
+            Object[] items = array;
+            int n = count;
+            if (n < items.length)
+                array = Arrays.copyOf(items, n);
         } finally {
             lock.unlock();
         }
@@ -1006,7 +1023,7 @@ public class ReadMostlyVector<E> impleme
     /** See {@link Vector#ensureCapacity} */
     public void ensureCapacity(int minCapacity) {
         if (minCapacity > 0) {
-            SequenceLock lock = this.lock;
+            final SequenceLock lock = this.lock;
             lock.lock();
             try {
                 if (minCapacity - array.length > 0)
@@ -1019,12 +1036,11 @@ public class ReadMostlyVector<E> impleme
 
     /** See {@link Vector#elements} */
     public Enumeration<E> elements() {
-        return new Itr(this, 0);
+        return new Itr<E>(this, 0);
     }
 
     /** See {@link Vector#capacity} */
     public int capacity() {
-        long ignore = lock.getSequence();
         return array.length;
     }
 
@@ -1065,8 +1081,8 @@ public class ReadMostlyVector<E> impleme
 
     // other methods
 
-    public Object clone() {
-        SequenceLock lock = this.lock;
+    public ReadMostlyVector<E> clone() {
+        final SequenceLock lock = this.lock;
         Object[] a = null;
         boolean retry = false;
         long seq = lock.awaitAvailability();
@@ -1085,12 +1101,12 @@ public class ReadMostlyVector<E> impleme
                 lock.unlock();
             }
         }
-        return new ReadMostlyVector(a, n, capacityIncrement);
+        return new ReadMostlyVector<E>(a, n, capacityIncrement);
     }
 
     private void writeObject(java.io.ObjectOutputStream s)
             throws java.io.IOException {
-        SequenceLock lock = this.lock;
+        final SequenceLock lock = this.lock;
         lock.lock();
         try {
             s.defaultWriteObject();
@@ -1099,11 +1115,11 @@ public class ReadMostlyVector<E> impleme
         }
     }
 
-    static final class Itr<E> implements ListIterator<E>, Enumeration<E>  {
+    static final class Itr<E> implements ListIterator<E>, Enumeration<E> {
         final ReadMostlyVector<E> list;
         final SequenceLock lock;
         Object[] items;
-        Object next, prev;
+        E next, prev;
         long seq;
         int cursor;
         int fence;
@@ -1129,6 +1145,7 @@ public class ReadMostlyVector<E> impleme
                      lock.getSequence() != seq);
         }
 
+        @SuppressWarnings("unchecked")
         public boolean hasNext() {
             boolean valid;
             int i = cursor;
@@ -1137,7 +1154,7 @@ public class ReadMostlyVector<E> impleme
                     valid = false;
                     break;
                 }
-                next = items[i];
+                next = (E) items[i];
                 if (lock.getSequence() == seq) {
                     valid = true;
                     break;
@@ -1147,6 +1164,7 @@ public class ReadMostlyVector<E> impleme
             return validNext = valid;
         }
 
+        @SuppressWarnings("unchecked")
         public boolean hasPrevious() {
             boolean valid;
             int i = cursor - 1;
@@ -1155,7 +1173,7 @@ public class ReadMostlyVector<E> impleme
                     valid = false;
                     break;
                 }
-                prev = items[i];
+                prev = (E) items[i];
                 if (lock.getSequence() == seq) {
                     valid = true;
                     break;
@@ -1169,7 +1187,7 @@ public class ReadMostlyVector<E> impleme
             if (validNext || hasNext()) {
                 validNext = false;
                 lastRet = cursor++;
-                return (E) next;
+                return next;
             }
             throw new NoSuchElementException();
         }
@@ -1178,7 +1196,7 @@ public class ReadMostlyVector<E> impleme
             if (validPrev || hasPrevious()) {
                 validPrev = false;
                 lastRet = cursor--;
-                return (E) prev;
+                return prev;
             }
             throw new NoSuchElementException();
         }
@@ -1235,12 +1253,16 @@ public class ReadMostlyVector<E> impleme
         public int previousIndex() { return cursor - 1; }
     }
 
-    static final class ReadMostlyVectorSublist<E> implements List<E>, RandomAccess, java.io.Serializable {
+    static final class ReadMostlyVectorSublist<E>
+            implements List<E>, RandomAccess, java.io.Serializable {
+        static final long serialVersionUID = 3041673470172026059L;
+
         final ReadMostlyVector<E> list;
         final int offset;
         volatile int size;
 
-        ReadMostlyVectorSublist(ReadMostlyVector<E> list, int offset, int size) {
+        ReadMostlyVectorSublist(ReadMostlyVector<E> list,
+                                int offset, int size) {
             this.list = list;
             this.offset = offset;
             this.size = size;
@@ -1252,11 +1274,11 @@ public class ReadMostlyVector<E> impleme
         }
 
         public boolean add(E element) {
-            SequenceLock lock = list.lock;
+            final SequenceLock lock = list.lock;
             lock.lock();
             try {
                 int c = size;
-                list.internalAddAt(c + offset, element);
+                list.rawAddAt(c + offset, element);
                 size = c + 1;
             } finally {
                 lock.unlock();
@@ -1265,12 +1287,12 @@ public class ReadMostlyVector<E> impleme
         }
 
         public void add(int index, E element) {
-            SequenceLock lock = list.lock;
+            final SequenceLock lock = list.lock;
             lock.lock();
             try {
                 if (index < 0 || index > size)
                     throw new ArrayIndexOutOfBoundsException(index);
-                list.internalAddAt(index + offset, element);
+                list.rawAddAt(index + offset, element);
                 ++size;
             } finally {
                 lock.unlock();
@@ -1279,42 +1301,40 @@ public class ReadMostlyVector<E> impleme
 
         public boolean addAll(Collection<? extends E> c) {
             Object[] elements = c.toArray();
-            int added;
-            SequenceLock lock = list.lock;
+            final SequenceLock lock = list.lock;
             lock.lock();
             try {
                 int s = size;
                 int pc = list.count;
-                list.internalAddAllAt(offset + s, elements);
-                added = list.count - pc;
+                list.rawAddAllAt(offset + s, elements);
+                int added = list.count - pc;
                 size = s + added;
+                return added != 0;
             } finally {
                 lock.unlock();
             }
-            return added != 0;
         }
 
         public boolean addAll(int index, Collection<? extends E> c) {
             Object[] elements = c.toArray();
-            int added;
-            SequenceLock lock = list.lock;
+            final SequenceLock lock = list.lock;
             lock.lock();
             try {
                 int s = size;
                 if (index < 0 || index > s)
                     throw new ArrayIndexOutOfBoundsException(index);
                 int pc = list.count;
-                list.internalAddAllAt(index + offset, elements);
-                added = list.count - pc;
+                list.rawAddAllAt(index + offset, elements);
+                int added = list.count - pc;
                 size = s + added;
+                return added != 0;
             } finally {
                 lock.unlock();
             }
-            return added != 0;
         }
 
         public void clear() {
-            SequenceLock lock = list.lock;
+            final SequenceLock lock = list.lock;
             lock.lock();
             try {
                 list.internalClear(offset, offset + size);
@@ -1351,18 +1371,19 @@ public class ReadMostlyVector<E> impleme
         }
 
         public int indexOf(Object o) {
-            SequenceLock lock = list.lock;
+            final SequenceLock lock = list.lock;
             long seq = lock.awaitAvailability();
             Object[] items = list.array;
             int c = list.count;
             if (c <= items.length) {
-                int idx = list.validatedIndexOf(o, items, offset, offset+size, seq);
+                int idx = list.validatedIndexOf(o, items, offset,
+                                                offset + size, seq);
                 if (lock.getSequence() == seq)
                     return idx < 0 ? -1 : idx - offset;
             }
             lock.lock();
             try {
-                int idx = list.rawIndexOf(o, offset, offset+size);
+                int idx = list.rawIndexOf(o, offset, offset + size);
                 return idx < 0 ? -1 : idx - offset;
             } finally {
                 lock.unlock();
@@ -1374,11 +1395,11 @@ public class ReadMostlyVector<E> impleme
         }
 
         public Iterator<E> iterator() {
-            return new SubItr(this, offset);
+            return new SubItr<E>(this, offset);
         }
 
         public int lastIndexOf(Object o) {
-            SequenceLock lock = list.lock;
+            final SequenceLock lock = list.lock;
             long seq = lock.awaitAvailability();
             Object[] items = list.array;
             int c = list.count;
@@ -1398,44 +1419,45 @@ public class ReadMostlyVector<E> impleme
         }
 
         public ListIterator<E> listIterator() {
-            return new SubItr(this, offset);
+            return new SubItr<E>(this, offset);
         }
 
         public ListIterator<E> listIterator(int index) {
-            return new SubItr(this, index + offset);
+            return new SubItr<E>(this, index + offset);
         }
 
         public E remove(int index) {
-            Object result;
-            SequenceLock lock = list.lock;
+            final SequenceLock lock = list.lock;
             lock.lock();
             try {
-                if (index < 0 || index >= size)
-                    throw new ArrayIndexOutOfBoundsException(index);
+                Object[] items = list.array;
                 int i = index + offset;
-                result = list.array[i];
-                list.internalRemoveAt(i);
+                if (index < 0 || index >= size || i >= items.length)
+                    throw new ArrayIndexOutOfBoundsException(index);
+                @SuppressWarnings("unchecked")
+                E result = (E) items[i];
+                list.rawRemoveAt(i);
                 size--;
+                return result;
             } finally {
                 lock.unlock();
             }
-            return (E)result;
         }
 
         public boolean remove(Object o) {
-            boolean removed = false;
-            SequenceLock lock = list.lock;
+            final SequenceLock lock = list.lock;
             lock.lock();
             try {
-                if (list.internalRemoveAt(list.rawIndexOf(o, offset,
-                                                          offset + size))) {
-                    removed = true;
+                if (list.rawRemoveAt(list.rawIndexOf(o, offset,
+                                                     offset + size))) {
                     --size;
+                    return true;
                 }
+                else
+                    return false;
             } finally {
                 lock.unlock();
             }
-            return removed;
         }
 
         public boolean removeAll(Collection<?> c) {
@@ -1461,7 +1483,7 @@ public class ReadMostlyVector<E> impleme
             int ssize = toIndex - fromIndex;
             if (fromIndex < 0 || toIndex > c || ssize < 0)
                 throw new IndexOutOfBoundsException();
-            return new ReadMostlyVectorSublist(list, offset+fromIndex, ssize);
+            return new ReadMostlyVectorSublist<E>(list, offset+fromIndex, ssize);
         }
 
         public Object[] toArray() {
@@ -1483,7 +1505,7 @@ public class ReadMostlyVector<E> impleme
         final ReadMostlyVector<E> list;
         final SequenceLock lock;
         Object[] items;
-        Object next, prev;
+        E next, prev;
         long seq;
         int cursor;
         int fence;
@@ -1514,6 +1536,7 @@ public class ReadMostlyVector<E> impleme
             } while (lock.getSequence() != seq);
         }
 
+        @SuppressWarnings("unchecked")
         public boolean hasNext() {
             boolean valid;
             int i = cursor;
@@ -1522,7 +1545,7 @@ public class ReadMostlyVector<E> impleme
                     valid = false;
                     break;
                 }
-                next = items[i];
+                next = (E) items[i];
                 if (lock.getSequence() == seq) {
                     valid = true;
                     break;
@@ -1532,6 +1555,7 @@ public class ReadMostlyVector<E> impleme
             return validNext = valid;
         }
 
+        @SuppressWarnings("unchecked")
         public boolean hasPrevious() {
             boolean valid;
             int i = cursor - 1;
@@ -1540,7 +1564,7 @@ public class ReadMostlyVector<E> impleme
                     valid = false;
                     break;
                 }
-                prev = items[i];
+                prev = (E) items[i];
                 if (lock.getSequence() == seq) {
                     valid = true;
                     break;
@@ -1554,7 +1578,7 @@ public class ReadMostlyVector<E> impleme
             if (validNext || hasNext()) {
                 validNext = false;
                 lastRet = cursor++;
-                return (E) next;
+                return next;
             }
             throw new NoSuchElementException();
         }
@@ -1563,7 +1587,7 @@ public class ReadMostlyVector<E> impleme
             if (validPrev || hasPrevious()) {
                 validPrev = false;
                 lastRet = cursor--;
-                return (E) prev;
+                return prev;
             }
             throw new NoSuchElementException();
         }