--- jsr166/src/main/java/util/Vector.java 2007/05/20 07:54:01 1.21 +++ jsr166/src/main/java/util/Vector.java 2007/09/11 15:38:19 1.22 @@ -1,5 +1,5 @@ /* - * Copyright 1994-2006 Sun Microsystems, Inc. All Rights Reserved. + * Copyright 1994-2007 Sun Microsystems, Inc. All Rights Reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it @@ -41,15 +41,18 @@ package java.util; * capacity of a vector before inserting a large number of * components; this reduces the amount of incremental reallocation. * - *

The Iterators returned by Vector's iterator and listIterator - * methods are fail-fast: if the Vector is structurally modified - * at any time after the Iterator is created, in any way except through the - * Iterator's own remove or add methods, the Iterator will throw a - * ConcurrentModificationException. Thus, in the face of concurrent - * modification, the Iterator fails quickly and cleanly, rather than risking - * arbitrary, non-deterministic behavior at an undetermined time in the future. - * The Enumerations returned by Vector's elements method are not - * fail-fast. + *

+ * The iterators returned by this class's {@link #iterator() iterator} and + * {@link #listIterator(int) listIterator} methods are fail-fast: + * if the vector is structurally modified at any time after the iterator is + * created, in any way except through the iterator's own + * {@link ListIterator#remove() remove} or + * {@link ListIterator#add(Object) add} methods, the iterator will throw a + * {@link ConcurrentModificationException}. Thus, in the face of + * concurrent modification, the iterator fails quickly and cleanly, rather + * than risking arbitrary, non-deterministic behavior at an undetermined + * time in the future. The {@link Enumeration Enumerations} returned by + * the {@link #elements() elements} method are not fail-fast. * *

Note that the fail-fast behavior of an iterator cannot be guaranteed * as it is, generally speaking, impossible to make any hard guarantees in the @@ -317,7 +320,7 @@ public class Vector public E nextElement() { synchronized (Vector.this) { if (count < elementCount) { - return (E)elementData[count++]; + return elementData(count++); } } throw new NoSuchElementException("Vector Enumeration"); @@ -445,7 +448,7 @@ public class Vector throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount); } - return (E)elementData[index]; + return elementData(index); } /** @@ -459,7 +462,7 @@ public class Vector if (elementCount == 0) { throw new NoSuchElementException(); } - return (E)elementData[0]; + return elementData(0); } /** @@ -473,7 +476,7 @@ public class Vector if (elementCount == 0) { throw new NoSuchElementException(); } - return (E)elementData[elementCount - 1]; + return elementData(elementCount - 1); } /** @@ -641,7 +644,8 @@ public class Vector */ public synchronized Object clone() { try { - Vector v = (Vector) super.clone(); + @SuppressWarnings("unchecked") + Vector v = (Vector) super.clone(); v.elementData = Arrays.copyOf(elementData, elementCount); v.modCount = 0; return v; @@ -684,6 +688,7 @@ public class Vector * @throws NullPointerException if the given array is null * @since 1.2 */ + @SuppressWarnings("unchecked") public synchronized T[] toArray(T[] a) { if (a.length < elementCount) return (T[]) Arrays.copyOf(elementData, elementCount, a.getClass()); @@ -698,6 +703,11 @@ public class Vector // Positional Access Operations + @SuppressWarnings("unchecked") + E elementData(int index) { + return (E) elementData[index]; + } + /** * Returns the element at the specified position in this Vector. * @@ -711,7 +721,7 @@ public class Vector if (index >= elementCount) throw new ArrayIndexOutOfBoundsException(index); - return (E)elementData[index]; + return elementData(index); } /** @@ -729,9 +739,9 @@ public class Vector if (index >= elementCount) throw new ArrayIndexOutOfBoundsException(index); - Object oldValue = elementData[index]; + E oldValue = elementData(index); elementData[index] = element; - return (E)oldValue; + return oldValue; } /** @@ -793,7 +803,7 @@ public class Vector modCount++; if (index >= elementCount) throw new ArrayIndexOutOfBoundsException(index); - Object oldValue = elementData[index]; + E oldValue = elementData(index); int numMoved = elementCount - index - 1; if (numMoved > 0) @@ -801,7 +811,7 @@ public class Vector numMoved); elementData[--elementCount] = null; // Let gc do its work - return (E)oldValue; + return oldValue; } /** @@ -959,14 +969,50 @@ public class Vector } /** - * Removes from this List all of the elements whose index is between - * fromIndex, inclusive and toIndex, exclusive. Shifts any succeeding - * elements to the left (reduces their index). - * This call shortens the Vector by (toIndex - fromIndex) elements. (If - * toIndex==fromIndex, this operation has no effect.) + * Returns a view of the portion of this List between fromIndex, + * inclusive, and toIndex, exclusive. (If fromIndex and toIndex are + * equal, the returned List is empty.) The returned List is backed by this + * List, so changes in the returned List are reflected in this List, and + * vice-versa. The returned List supports all of the optional List + * operations supported by this List. * - * @param fromIndex index of first element to be removed - * @param toIndex index after last element to be removed + *

This method eliminates the need for explicit range operations (of + * the sort that commonly exist for arrays). Any operation that expects + * a List can be used as a range operation by operating on a subList view + * instead of a whole List. For example, the following idiom + * removes a range of elements from a List: + * 

+     *	    list.subList(from, to).clear();
+     *
+ * Similar idioms may be constructed for indexOf and lastIndexOf, + * and all of the algorithms in the Collections class can be applied to + * a subList. + * + *

The semantics of the List returned by this method become undefined if + * the backing list (i.e., this List) is structurally modified in + * any way other than via the returned List. (Structural modifications are + * those that change the size of the List, or otherwise perturb it in such + * a fashion that iterations in progress may yield incorrect results.) + * + * @param fromIndex low endpoint (inclusive) of the subList + * @param toIndex high endpoint (exclusive) of the subList + * @return a view of the specified range within this List + * @throws IndexOutOfBoundsException if an endpoint index value is out of range + * {@code (fromIndex < 0 || toIndex > size)} + * @throws IllegalArgumentException if the endpoint indices are out of order + * {@code (fromIndex > toIndex)} + */ + public synchronized List subList(int fromIndex, int toIndex) { + return Collections.synchronizedList(super.subList(fromIndex, toIndex), + this); + } + + /** + * Removes from this list all of the elements whose index is between + * {@code fromIndex}, inclusive, and {@code toIndex}, exclusive. + * Shifts any succeeding elements to the left (reduces their index). + * This call shortens the list by {@code (toIndex - fromIndex)} elements. + * (If {@code toIndex==fromIndex}, this operation has no effect.) */ protected synchronized void removeRange(int fromIndex, int toIndex) { modCount++; @@ -992,87 +1038,100 @@ public class Vector } /** - * Returns a list-iterator of the elements in this list (in proper + * Returns a list iterator over the elements in this list (in proper * sequence), starting at the specified position in the list. - * Obeys the general contract of {@link List#listIterator(int)}. + * The specified index indicates the first element that would be + * returned by an initial call to {@link ListIterator#next next}. + * An initial call to {@link ListIterator#previous previous} would + * return the element with the specified index minus one. + * + *

The returned list iterator is fail-fast. * - *

The list-iterator is fail-fast: if the list is structurally - * modified at any time after the Iterator is created, in any way except - * through the list-iterator's own {@code remove} or {@code add} - * methods, the list-iterator will throw a - * {@code ConcurrentModificationException}. Thus, in the face of - * concurrent modification, the iterator fails quickly and cleanly, rather - * than risking arbitrary, non-deterministic behavior at an undetermined - * time in the future. - * - * @param index index of the first element to be returned from the - * list-iterator (by a call to {@link ListIterator#next}) - * @return a list-iterator of the elements in this list (in proper - * sequence), starting at the specified position in the list * @throws IndexOutOfBoundsException {@inheritDoc} */ public synchronized ListIterator listIterator(int index) { if (index < 0 || index > elementCount) throw new IndexOutOfBoundsException("Index: "+index); - return new VectorIterator(index, elementCount); + return new ListItr(index); } /** - * {@inheritDoc} + * Returns a list iterator over the elements in this list (in proper + * sequence). + * + *

The returned list iterator is fail-fast. + * + * @see #listIterator(int) */ public synchronized ListIterator listIterator() { - return new VectorIterator(0, elementCount); + return new ListItr(0); } /** * Returns an iterator over the elements in this list in proper sequence. * + *

The returned iterator is fail-fast. + * * @return an iterator over the elements in this list in proper sequence */ public synchronized Iterator iterator() { - return new VectorIterator(0, elementCount); + return new Itr(); } /** - * Helper method to access array elements under synchronization by - * iterators. The caller performs index check with respect to - * expected bounds, so errors accessing the element are reported - * as ConcurrentModificationExceptions. + * An optimized version of AbstractList.Itr */ - final synchronized Object iteratorGet(int index, int expectedModCount) { - if (modCount == expectedModCount) { - try { - return elementData[index]; - } catch(IndexOutOfBoundsException fallThrough) { + private class Itr implements Iterator { + int cursor; // index of next element to return + int lastRet = -1; // index of last element returned; -1 if no such + int expectedModCount = modCount; + + public boolean hasNext() { + // Racy but within spec, since modifications are checked + // within or after synchronization in next/previous + return cursor != elementCount; + } + + public E next() { + synchronized (Vector.this) { + checkForComodification(); + int i = cursor; + if (i >= elementCount) + throw new NoSuchElementException(); + cursor = i + 1; + return elementData(lastRet = i); + } + } + + public void remove() { + if (lastRet == -1) + throw new IllegalStateException(); + synchronized (Vector.this) { + checkForComodification(); + Vector.this.remove(lastRet); + expectedModCount = modCount; } - } - throw new ConcurrentModificationException(); + cursor = lastRet; + lastRet = -1; + } + + final void checkForComodification() { + if (modCount != expectedModCount) + throw new ConcurrentModificationException(); + } } /** - * Streamlined specialization of AbstractList version of iterator. - * Locally performs bounds checks, but relies on outer Vector - * to access elements under synchronization. + * An optimized version of AbstractList.ListItr */ - private final class VectorIterator implements ListIterator { - int cursor; // Index of next element to return; - int fence; // Upper bound on cursor (cache of size()) - int lastRet; // Index of last element, or -1 if no such - int expectedModCount; // To check for CME - - VectorIterator(int index, int fence) { - this.cursor = index; - this.fence = fence; - this.lastRet = -1; - this.expectedModCount = Vector.this.modCount; - } - - public boolean hasNext() { - return cursor < fence; + final class ListItr extends Itr implements ListIterator { + ListItr(int index) { + super(); + cursor = index; } public boolean hasPrevious() { - return cursor > 0; + return cursor != 0; } public int nextIndex() { @@ -1083,383 +1142,35 @@ public class Vector return cursor - 1; } - public E next() { - int i = cursor; - if (i >= fence) - throw new NoSuchElementException(); - Object next = Vector.this.iteratorGet(i, expectedModCount); - lastRet = i; - cursor = i + 1; - return (E)next; - } - - public E previous() { - int i = cursor - 1; - if (i < 0) - throw new NoSuchElementException(); - Object prev = Vector.this.iteratorGet(i, expectedModCount); - lastRet = i; - cursor = i; - return (E)prev; + public E previous() { + synchronized (Vector.this) { + checkForComodification(); + int i = cursor - 1; + if (i < 0) + throw new NoSuchElementException(); + cursor = i; + return elementData(lastRet = i); + } } public void set(E e) { - if (lastRet < 0) - throw new IllegalStateException(); - if (Vector.this.modCount != expectedModCount) - throw new ConcurrentModificationException(); - try { - Vector.this.set(lastRet, e); - expectedModCount = Vector.this.modCount; - } catch (IndexOutOfBoundsException ex) { - throw new ConcurrentModificationException(); - } - } - - public void remove() { - int i = lastRet; - if (i < 0) + if (lastRet == -1) throw new IllegalStateException(); - if (Vector.this.modCount != expectedModCount) - throw new ConcurrentModificationException(); - try { - Vector.this.remove(i); - if (i < cursor) - cursor--; - lastRet = -1; - fence = Vector.this.size(); - expectedModCount = Vector.this.modCount; - } catch (IndexOutOfBoundsException ex) { - throw new ConcurrentModificationException(); + synchronized (Vector.this) { + checkForComodification(); + Vector.this.set(lastRet, e); } } public void add(E e) { - if (Vector.this.modCount != expectedModCount) - throw new ConcurrentModificationException(); - try { - int i = cursor; - Vector.this.add(i, e); - cursor = i + 1; - lastRet = -1; - fence = Vector.this.size(); - expectedModCount = Vector.this.modCount; - } catch (IndexOutOfBoundsException ex) { - throw new ConcurrentModificationException(); + int i = cursor; + synchronized (Vector.this) { + checkForComodification(); + Vector.this.add(i, e); + expectedModCount = modCount; } + cursor = i + 1; + lastRet = -1; } } - - /** - * Returns a view of the portion of this List between fromIndex, - * inclusive, and toIndex, exclusive. (If fromIndex and toIndex are - * equal, the returned List is empty.) The returned List is backed by this - * List, so changes in the returned List are reflected in this List, and - * vice-versa. The returned List supports all of the optional List - * operations supported by this List. - * - *

This method eliminates the need for explicit range operations (of - * the sort that commonly exist for arrays). Any operation that expects - * a List can be used as a range operation by operating on a subList view - * instead of a whole List. For example, the following idiom - * removes a range of elements from a List: - * 

-     *	    list.subList(from, to).clear();
-     *
- * Similar idioms may be constructed for indexOf and lastIndexOf, - * and all of the algorithms in the Collections class can be applied to - * a subList. - * - *

The semantics of the List returned by this method become undefined if - * the backing list (i.e., this List) is structurally modified in - * any way other than via the returned List. (Structural modifications are - * those that change the size of the List, or otherwise perturb it in such - * a fashion that iterations in progress may yield incorrect results.) - * - * @param fromIndex low endpoint (inclusive) of the subList - * @param toIndex high endpoint (exclusive) of the subList - * @return a view of the specified range within this List - * @throws IndexOutOfBoundsException if an endpoint index value is out of range - * {@code (fromIndex < 0 || toIndex > size)} - * @throws IllegalArgumentException if the endpoint indices are out of order - * {@code (fromIndex > toIndex)} - */ - public synchronized List subList(int fromIndex, int toIndex) { - return new VectorSubList(this, this, fromIndex, fromIndex, toIndex); - } - - /** - * This class specializes the AbstractList version of SubList to - * avoid the double-indirection penalty that would arise using a - * synchronized wrapper, as well as to avoid some unnecessary - * checks in sublist iterators. - */ - private static final class VectorSubList extends AbstractList implements RandomAccess { - final Vector base; // base list - final AbstractList parent; // Creating list - final int baseOffset; // index wrt Vector - final int parentOffset; // index wrt parent - int length; // length of sublist - - VectorSubList(Vector base, AbstractList parent, int baseOffset, - int fromIndex, int toIndex) { - if (fromIndex < 0) - throw new IndexOutOfBoundsException("fromIndex = " + fromIndex); - if (toIndex > parent.size()) - throw new IndexOutOfBoundsException("toIndex = " + toIndex); - if (fromIndex > toIndex) - throw new IllegalArgumentException("fromIndex(" + fromIndex + - ") > toIndex(" + toIndex + ")"); - - this.base = base; - this.parent = parent; - this.baseOffset = baseOffset; - this.parentOffset = fromIndex; - this.length = toIndex - fromIndex; - modCount = base.modCount; - } - - /** - * Returns an IndexOutOfBoundsException with nicer message - */ - private IndexOutOfBoundsException indexError(int index) { - return new IndexOutOfBoundsException("Index: " + index + - ", Size: " + length); - } - - public E set(int index, E element) { - synchronized(base) { - if (index < 0 || index >= length) - throw indexError(index); - if (base.modCount != modCount) - throw new ConcurrentModificationException(); - return base.set(index + baseOffset, element); - } - } - - public E get(int index) { - synchronized(base) { - if (index < 0 || index >= length) - throw indexError(index); - if (base.modCount != modCount) - throw new ConcurrentModificationException(); - return base.get(index + baseOffset); - } - } - - public int size() { - synchronized(base) { - if (base.modCount != modCount) - throw new ConcurrentModificationException(); - return length; - } - } - - public void add(int index, E element) { - synchronized(base) { - if (index < 0 || index > length) - throw indexError(index); - if (base.modCount != modCount) - throw new ConcurrentModificationException(); - parent.add(index + parentOffset, element); - length++; - modCount = base.modCount; - } - } - - public E remove(int index) { - synchronized(base) { - if (index < 0 || index >= length) - throw indexError(index); - if (base.modCount != modCount) - throw new ConcurrentModificationException(); - E result = parent.remove(index + parentOffset); - length--; - modCount = base.modCount; - return result; - } - } - - protected void removeRange(int fromIndex, int toIndex) { - synchronized(base) { - if (base.modCount != modCount) - throw new ConcurrentModificationException(); - parent.removeRange(fromIndex + parentOffset, - toIndex + parentOffset); - length -= (toIndex-fromIndex); - modCount = base.modCount; - } - } - - public boolean addAll(Collection c) { - return addAll(length, c); - } - - public boolean addAll(int index, Collection c) { - synchronized(base) { - if (index < 0 || index > length) - throw indexError(index); - int cSize = c.size(); - if (cSize==0) - return false; - - if (base.modCount != modCount) - throw new ConcurrentModificationException(); - parent.addAll(parentOffset + index, c); - modCount = base.modCount; - length += cSize; - return true; - } - } - - public boolean equals(Object o) { - synchronized(base) {return super.equals(o);} - } - - public int hashCode() { - synchronized(base) {return super.hashCode();} - } - - public int indexOf(Object o) { - synchronized(base) {return super.indexOf(o);} - } - - public int lastIndexOf(Object o) { - synchronized(base) {return super.lastIndexOf(o);} - } - - public List subList(int fromIndex, int toIndex) { - return new VectorSubList(base, this, fromIndex + baseOffset, - fromIndex, toIndex); - } - - public Iterator iterator() { - synchronized(base) { - return new VectorSubListIterator(this, 0); - } - } - - public synchronized ListIterator listIterator() { - synchronized(base) { - return new VectorSubListIterator(this, 0); - } - } - - public ListIterator listIterator(int index) { - synchronized(base) { - if (index < 0 || index > length) - throw indexError(index); - return new VectorSubListIterator(this, index); - } - } - - /** - * Same idea as VectorIterator, except routing structural - * change operations through the sublist. - */ - private static final class VectorSubListIterator implements ListIterator { - final Vector base; // base list - final VectorSubList outer; // Sublist creating this iteraor - final int offset; // cursor offset wrt base - int cursor; // Current index - int fence; // Upper bound on cursor - int lastRet; // Index of returned element, or -1 - int expectedModCount; // Expected modCount of base Vector - - VectorSubListIterator(VectorSubList list, int index) { - this.lastRet = -1; - this.cursor = index; - this.outer = list; - this.offset = list.baseOffset; - this.fence = list.length; - this.base = list.base; - this.expectedModCount = base.modCount; - } - - public boolean hasNext() { - return cursor < fence; - } - - public boolean hasPrevious() { - return cursor > 0; - } - - public int nextIndex() { - return cursor; - } - - public int previousIndex() { - return cursor - 1; - } - - public E next() { - int i = cursor; - if (cursor >= fence) - throw new NoSuchElementException(); - Object next = base.iteratorGet(i + offset, expectedModCount); - lastRet = i; - cursor = i + 1; - return (E)next; - } - - public E previous() { - int i = cursor - 1; - if (i < 0) - throw new NoSuchElementException(); - Object prev = base.iteratorGet(i + offset, expectedModCount); - lastRet = i; - cursor = i; - return (E)prev; - } - - public void set(E e) { - if (lastRet < 0) - throw new IllegalStateException(); - if (base.modCount != expectedModCount) - throw new ConcurrentModificationException(); - try { - outer.set(lastRet, e); - expectedModCount = base.modCount; - } catch (IndexOutOfBoundsException ex) { - throw new ConcurrentModificationException(); - } - } - - public void remove() { - int i = lastRet; - if (i < 0) - throw new IllegalStateException(); - if (base.modCount != expectedModCount) - throw new ConcurrentModificationException(); - try { - outer.remove(i); - if (i < cursor) - cursor--; - lastRet = -1; - fence = outer.length; - expectedModCount = base.modCount; - } catch (IndexOutOfBoundsException ex) { - throw new ConcurrentModificationException(); - } - } - - public void add(E e) { - if (base.modCount != expectedModCount) - throw new ConcurrentModificationException(); - try { - int i = cursor; - outer.add(i, e); - cursor = i + 1; - lastRet = -1; - fence = outer.length; - expectedModCount = base.modCount; - } catch (IndexOutOfBoundsException ex) { - throw new ConcurrentModificationException(); - } - } - } - } } - - -