--- jsr166/src/main/java/util/Vector.java 2006/04/21 20:49:03 1.12 +++ jsr166/src/main/java/util/Vector.java 2007/09/11 15:38:19 1.22 @@ -1,49 +1,70 @@ /* - * %W% %E% + * Copyright 1994-2007 Sun Microsystems, Inc. All Rights Reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * - * Copyright 2006 Sun Microsystems, Inc. All rights reserved. - * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. Sun designates this + * particular file as subject to the "Classpath" exception as provided + * by Sun in the LICENSE file that accompanied this code. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, + * CA 95054 USA or visit www.sun.com if you need additional information or + * have any questions. */ package java.util; /** - * The Vector class implements a growable array of + * The {@code Vector} class implements a growable array of * objects. Like an array, it contains components that can be * accessed using an integer index. However, the size of a - * Vector can grow or shrink as needed to accommodate - * adding and removing items after the Vector has been created. + * {@code Vector} can grow or shrink as needed to accommodate + * adding and removing items after the {@code Vector} has been created. * *

Each vector tries to optimize storage management by maintaining a - * capacity and a capacityIncrement. The - * capacity is always at least as large as the vector + * {@code capacity} and a {@code capacityIncrement}. The + * {@code capacity} is always at least as large as the vector * size; it is usually larger because as components are added to the * vector, the vector's storage increases in chunks the size of - * capacityIncrement. An application can increase the + * {@code capacityIncrement}. An application can increase the * 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 * presence of unsynchronized concurrent modification. Fail-fast iterators - * throw ConcurrentModificationException on a best-effort basis. + * throw {@code ConcurrentModificationException} on a best-effort basis. * Therefore, it would be wrong to write a program that depended on this * exception for its correctness: the fail-fast behavior of iterators * should be used only to detect bugs. * *

As of the Java 2 platform v1.2, this class was retrofitted to * implement the {@link List} interface, making it a member of the - * Java + * Java * Collections Framework. Unlike the new collection * implementations, {@code Vector} is synchronized. * @@ -63,18 +84,18 @@ public class Vector /** * The array buffer into which the components of the vector are * stored. The capacity of the vector is the length of this array buffer, - * and is at least large enough to contain all the vector's elements.

+ * and is at least large enough to contain all the vector's elements. * - * Any array elements following the last element in the Vector are null. + *

Any array elements following the last element in the Vector are null. * * @serial */ protected Object[] elementData; /** - * The number of valid components in this Vector object. - * Components elementData[0] through - * elementData[elementCount-1] are the actual items. + * The number of valid components in this {@code Vector} object. + * Components {@code elementData[0]} through + * {@code elementData[elementCount-1]} are the actual items. * * @serial */ @@ -100,8 +121,8 @@ public class Vector * @param initialCapacity the initial capacity of the vector * @param capacityIncrement the amount by which the capacity is * increased when the vector overflows - * @exception IllegalArgumentException if the specified initial capacity - * is negative + * @throws IllegalArgumentException if the specified initial capacity + * is negative */ public Vector(int initialCapacity, int capacityIncrement) { super(); @@ -117,8 +138,8 @@ public class Vector * with its capacity increment equal to zero. * * @param initialCapacity the initial capacity of the vector - * @exception IllegalArgumentException if the specified initial capacity - * is negative + * @throws IllegalArgumentException if the specified initial capacity + * is negative */ public Vector(int initialCapacity) { this(initialCapacity, 0); @@ -126,7 +147,7 @@ public class Vector /** * Constructs an empty vector so that its internal data array - * has size 10 and its standard capacity increment is + * has size {@code 10} and its standard capacity increment is * zero. */ public Vector() { @@ -153,8 +174,8 @@ public class Vector /** * Copies the components of this vector into the specified array. - * The item at index k in this vector is copied into - * component k of anArray. + * The item at index {@code k} in this vector is copied into + * component {@code k} of {@code anArray}. * * @param anArray the array into which the components get copied * @throws NullPointerException if the given array is null @@ -172,7 +193,7 @@ public class Vector * Trims the capacity of this vector to be the vector's current * size. If the capacity of this vector is larger than its current * size, then the capacity is changed to equal the size by replacing - * its internal data array, kept in the field elementData, + * its internal data array, kept in the field {@code elementData}, * with a smaller one. An application can use this operation to * minimize the storage of a vector. */ @@ -190,14 +211,14 @@ public class Vector * the minimum capacity argument. * *

If the current capacity of this vector is less than - * minCapacity, then its capacity is increased by replacing its - * internal data array, kept in the field elementData, with a + * {@code minCapacity}, then its capacity is increased by replacing its + * internal data array, kept in the field {@code elementData}, with a * larger one. The size of the new data array will be the old size plus - * capacityIncrement, unless the value of - * capacityIncrement is less than or equal to zero, in which case + * {@code capacityIncrement}, unless the value of + * {@code capacityIncrement} is less than or equal to zero, in which case * the new capacity will be twice the old capacity; but if this new size - * is still smaller than minCapacity, then the new capacity will - * be minCapacity. + * is still smaller than {@code minCapacity}, then the new capacity will + * be {@code minCapacity}. * * @param minCapacity the desired minimum capacity */ @@ -212,7 +233,7 @@ public class Vector * method for ensuring capacity without incurring the cost of an * extra synchronization. * - * @see java.util.Vector#ensureCapacity(int) + * @see #ensureCapacity(int) */ private void ensureCapacityHelper(int minCapacity) { int oldCapacity = elementData.length; @@ -229,12 +250,12 @@ public class Vector /** * Sets the size of this vector. If the new size is greater than the - * current size, new null items are added to the end of + * current size, new {@code null} items are added to the end of * the vector. If the new size is less than the current size, all - * components at index newSize and greater are discarded. + * components at index {@code newSize} and greater are discarded. * - * @param newSize the new size of this vector - * @throws ArrayIndexOutOfBoundsException if new size is negative + * @param newSize the new size of this vector + * @throws ArrayIndexOutOfBoundsException if the new size is negative */ public synchronized void setSize(int newSize) { modCount++; @@ -252,7 +273,7 @@ public class Vector * Returns the current capacity of this vector. * * @return the current capacity (the length of its internal - * data array, kept in the field elementData + * data array, kept in the field {@code elementData} * of this vector) */ public synchronized int capacity() { @@ -271,9 +292,9 @@ public class Vector /** * Tests if this vector has no components. * - * @return true if and only if this vector has + * @return {@code true} if and only if this vector has * no components, that is, its size is zero; - * false otherwise. + * {@code false} otherwise. */ public synchronized boolean isEmpty() { return elementCount == 0; @@ -281,12 +302,11 @@ public class Vector /** * Returns an enumeration of the components of this vector. The - * returned Enumeration object will generate all items in - * this vector. The first item generated is the item at index 0, - * then the item at index 1, and so on. + * returned {@code Enumeration} object will generate all items in + * this vector. The first item generated is the item at index {@code 0}, + * then the item at index {@code 1}, and so on. * * @return an enumeration of the components of this vector - * @see Enumeration * @see Iterator */ public Enumeration elements() { @@ -300,7 +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"); @@ -309,13 +329,13 @@ public class Vector } /** - * Returns true if this vector contains the specified element. - * More formally, returns true if and only if this vector - * contains at least one element e such that + * Returns {@code true} if this vector contains the specified element. + * More formally, returns {@code true} if and only if this vector + * contains at least one element {@code e} such that * (o==null ? e==null : o.equals(e)). * * @param o element whose presence in this vector is to be tested - * @return true if this vector contains the specified element + * @return {@code true} if this vector contains the specified element */ public boolean contains(Object o) { return indexOf(o, 0) >= 0; @@ -324,7 +344,7 @@ public class Vector /** * Returns the index of the first occurrence of the specified element * in this vector, or -1 if this vector does not contain the element. - * More formally, returns the lowest index i such that + * More formally, returns the lowest index {@code i} such that * (o==null ? get(i)==null : o.equals(get(i))), * or -1 if there is no such index. * @@ -338,17 +358,17 @@ public class Vector /** * Returns the index of the first occurrence of the specified element in - * this vector, searching forwards from index, or returns -1 if + * this vector, searching forwards from {@code index}, or returns -1 if * the element is not found. - * More formally, returns the lowest index i such that + * More formally, returns the lowest index {@code i} such that * (i >= index && (o==null ? get(i)==null : o.equals(get(i)))), * or -1 if there is no such index. * * @param o element to search for * @param index index to start searching from * @return the index of the first occurrence of the element in - * this vector at position index or later in the vector; - * -1 if the element is not found. + * this vector at position {@code index} or later in the vector; + * {@code -1} if the element is not found. * @throws IndexOutOfBoundsException if the specified index is negative * @see Object#equals(Object) */ @@ -368,7 +388,7 @@ public class Vector /** * Returns the index of the last occurrence of the specified element * in this vector, or -1 if this vector does not contain the element. - * More formally, returns the highest index i such that + * More formally, returns the highest index {@code i} such that * (o==null ? get(i)==null : o.equals(get(i))), * or -1 if there is no such index. * @@ -382,16 +402,16 @@ public class Vector /** * Returns the index of the last occurrence of the specified element in - * this vector, searching backwards from index, or returns -1 if + * this vector, searching backwards from {@code index}, or returns -1 if * the element is not found. - * More formally, returns the highest index i such that + * More formally, returns the highest index {@code i} such that * (i <= index && (o==null ? get(i)==null : o.equals(get(i)))), * or -1 if there is no such index. * * @param o element to search for * @param index index to start searching backwards from * @return the index of the last occurrence of the element at position - * less than or equal to index in this vector; + * less than or equal to {@code index} in this vector; * -1 if the element is not found. * @throws IndexOutOfBoundsException if the specified index is greater * than or equal to the current size of this vector @@ -413,39 +433,36 @@ public class Vector } /** - * Returns the component at the specified index.

+ * Returns the component at the specified index. * - * This method is identical in functionality to the get method - * (which is part of the List interface). + *

This method is identical in functionality to the {@link #get(int)} + * method (which is part of the {@link List} interface). * * @param index an index into this vector * @return the component at the specified index - * @exception ArrayIndexOutOfBoundsException if the index - * is negative or not less than the current size of this - * Vector object. - * @see #get(int) - * @see List + * @throws ArrayIndexOutOfBoundsException if the index is out of range + * ({@code index < 0 || index >= size()}) */ public synchronized E elementAt(int index) { if (index >= elementCount) { throw new ArrayIndexOutOfBoundsException(index + " >= " + elementCount); } - return (E)elementData[index]; + return elementData(index); } /** - * Returns the first component (the item at index 0) of + * Returns the first component (the item at index {@code 0}) of * this vector. * * @return the first component of this vector - * @exception NoSuchElementException if this vector has no components + * @throws NoSuchElementException if this vector has no components */ public synchronized E firstElement() { if (elementCount == 0) { throw new NoSuchElementException(); } - return (E)elementData[0]; + return elementData(0); } /** @@ -453,35 +470,34 @@ public class Vector * * @return the last component of the vector, i.e., the component at index * size() - 1. - * @exception NoSuchElementException if this vector is empty + * @throws NoSuchElementException if this vector is empty */ public synchronized E lastElement() { if (elementCount == 0) { throw new NoSuchElementException(); } - return (E)elementData[elementCount - 1]; + return elementData(elementCount - 1); } /** - * Sets the component at the specified index of this + * Sets the component at the specified {@code index} of this * vector to be the specified object. The previous component at that - * position is discarded.

+ * position is discarded. * - * The index must be a value greater than or equal to 0 - * and less than the current size of the vector.

+ *

The index must be a value greater than or equal to {@code 0} + * and less than the current size of the vector. * - * This method is identical in functionality to the set method - * (which is part of the List interface). Note that the set method reverses - * the order of the parameters, to more closely match array usage. Note - * also that the set method returns the old value that was stored at the - * specified position. + *

This method is identical in functionality to the + * {@link #set(int, Object) set(int, E)} + * method (which is part of the {@link List} interface). Note that the + * {@code set} method reverses the order of the parameters, to more closely + * match array usage. Note also that the {@code set} method returns the + * old value that was stored at the specified position. * * @param obj what the component is to be set to * @param index the specified index - * @exception ArrayIndexOutOfBoundsException if the index was invalid - * @see #size() - * @see List - * @see #set(int, java.lang.Object) + * @throws ArrayIndexOutOfBoundsException if the index is out of range + * ({@code index < 0 || index >= size()}) */ public synchronized void setElementAt(E obj, int index) { if (index >= elementCount) { @@ -494,22 +510,21 @@ public class Vector /** * Deletes the component at the specified index. Each component in * this vector with an index greater or equal to the specified - * index is shifted downward to have an index one + * {@code index} is shifted downward to have an index one * smaller than the value it had previously. The size of this vector - * is decreased by 1.

+ * is decreased by {@code 1}. * - * The index must be a value greater than or equal to 0 - * and less than the current size of the vector.

+ *

The index must be a value greater than or equal to {@code 0} + * and less than the current size of the vector. * - * This method is identical in functionality to the remove method - * (which is part of the List interface). Note that the remove method - * returns the old value that was stored at the specified position. + *

This method is identical in functionality to the {@link #remove(int)} + * method (which is part of the {@link List} interface). Note that the + * {@code remove} method returns the old value that was stored at the + * specified position. * * @param index the index of the object to remove - * @exception ArrayIndexOutOfBoundsException if the index was invalid - * @see #size() - * @see #remove(int) - * @see List + * @throws ArrayIndexOutOfBoundsException if the index is out of range + * ({@code index < 0 || index >= size()}) */ public synchronized void removeElementAt(int index) { modCount++; @@ -530,26 +545,26 @@ public class Vector /** * Inserts the specified object as a component in this vector at the - * specified index. Each component in this vector with - * an index greater or equal to the specified index is + * specified {@code index}. Each component in this vector with + * an index greater or equal to the specified {@code index} is * shifted upward to have an index one greater than the value it had - * previously.

+ * previously. * - * The index must be a value greater than or equal to 0 + *

The index must be a value greater than or equal to {@code 0} * and less than or equal to the current size of the vector. (If the * index is equal to the current size of the vector, the new element - * is appended to the Vector.)

+ * is appended to the Vector.) * - * This method is identical in functionality to the add(Object, int) method - * (which is part of the List interface). Note that the add method reverses - * the order of the parameters, to more closely match array usage. + *

This method is identical in functionality to the + * {@link #add(int, Object) add(int, E)} + * method (which is part of the {@link List} interface). Note that the + * {@code add} method reverses the order of the parameters, to more closely + * match array usage. * * @param obj the component to insert * @param index where to insert the new component - * @exception ArrayIndexOutOfBoundsException if the index was invalid - * @see #size() - * @see #add(int, Object) - * @see List + * @throws ArrayIndexOutOfBoundsException if the index is out of range + * ({@code index < 0 || index > size()}) */ public synchronized void insertElementAt(E obj, int index) { modCount++; @@ -566,14 +581,13 @@ public class Vector /** * Adds the specified component to the end of this vector, * increasing its size by one. The capacity of this vector is - * increased if its size becomes greater than its capacity.

+ * increased if its size becomes greater than its capacity. * - * This method is identical in functionality to the add(Object) method - * (which is part of the List interface). + *

This method is identical in functionality to the + * {@link #add(Object) add(E)} + * method (which is part of the {@link List} interface). * * @param obj the component to be added - * @see #add(Object) - * @see List */ public synchronized void addElement(E obj) { modCount++; @@ -586,16 +600,15 @@ public class Vector * from this vector. If the object is found in this vector, each * component in the vector with an index greater or equal to the * object's index is shifted downward to have an index one smaller - * than the value it had previously.

+ * than the value it had previously. * - * This method is identical in functionality to the remove(Object) - * method (which is part of the List interface). + *

This method is identical in functionality to the + * {@link #remove(Object)} method (which is part of the + * {@link List} interface). * * @param obj the component to be removed - * @return true if the argument was a component of this - * vector; false otherwise. - * @see List#remove(Object) - * @see List + * @return {@code true} if the argument was a component of this + * vector; {@code false} otherwise. */ public synchronized boolean removeElement(Object obj) { modCount++; @@ -608,13 +621,10 @@ public class Vector } /** - * Removes all components from this vector and sets its size to zero.

- * - * This method is identical in functionality to the clear method - * (which is part of the List interface). + * Removes all components from this vector and sets its size to zero. * - * @see #clear - * @see List + *

This method is identical in functionality to the {@link #clear} + * method (which is part of the {@link List} interface). */ public synchronized void removeAllElements() { modCount++; @@ -628,13 +638,14 @@ public class Vector /** * Returns a clone of this vector. The copy will contain a * reference to a clone of the internal data array, not a reference - * to the original internal data array of this Vector object. + * to the original internal data array of this {@code Vector} object. * * @return a clone of this 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; @@ -659,9 +670,9 @@ public class Vector * correct order; the runtime type of the returned array is that of the * specified array. If the Vector fits in the specified array, it is * returned therein. Otherwise, a new array is allocated with the runtime - * type of the specified array and the size of this Vector.

+ * type of the specified array and the size of this Vector. * - * If the Vector fits in the specified array with room to spare + *

If the Vector fits in the specified array with room to spare * (i.e., the array has more elements than the Vector), * the element in the array immediately following the end of the * Vector is set to null. (This is useful in determining the length @@ -672,11 +683,12 @@ public class Vector * be stored, if it is big enough; otherwise, a new array of the * same runtime type is allocated for this purpose. * @return an array containing the elements of the Vector - * @exception ArrayStoreException the runtime type of a is not a supertype + * @throws ArrayStoreException if the runtime type of a is not a supertype * of the runtime type of every element in this 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()); @@ -691,20 +703,25 @@ 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. * * @param index index of the element to return * @return object at the specified index - * @exception ArrayIndexOutOfBoundsException index is out of range (index - * < 0 || index >= size()) + * @throws ArrayIndexOutOfBoundsException if the index is out of range + * ({@code index < 0 || index >= size()}) * @since 1.2 */ public synchronized E get(int index) { if (index >= elementCount) throw new ArrayIndexOutOfBoundsException(index); - return (E)elementData[index]; + return elementData(index); } /** @@ -714,24 +731,24 @@ public class Vector * @param index index of the element to replace * @param element element to be stored at the specified position * @return the element previously at the specified position - * @exception ArrayIndexOutOfBoundsException index out of range - * (index < 0 || index >= size()) + * @throws ArrayIndexOutOfBoundsException if the index is out of range + * ({@code index < 0 || index >= size()}) * @since 1.2 */ public synchronized E set(int index, E element) { if (index >= elementCount) throw new ArrayIndexOutOfBoundsException(index); - Object oldValue = elementData[index]; + E oldValue = elementData(index); elementData[index] = element; - return (E)oldValue; + return oldValue; } /** * Appends the specified element to the end of this Vector. * * @param e element to be appended to this Vector - * @return true (as specified by {@link Collection#add}) + * @return {@code true} (as specified by {@link Collection#add}) * @since 1.2 */ public synchronized boolean add(E e) { @@ -745,7 +762,7 @@ public class Vector * Removes the first occurrence of the specified element in this Vector * If the Vector does not contain the element, it is unchanged. More * formally, removes the element with the lowest index i such that - * (o==null ? get(i)==null : o.equals(get(i))) (if such + * {@code (o==null ? get(i)==null : o.equals(get(i)))} (if such * an element exists). * * @param o element to be removed from this Vector, if present @@ -763,8 +780,8 @@ public class Vector * * @param index index at which the specified element is to be inserted * @param element element to be inserted - * @exception ArrayIndexOutOfBoundsException index is out of range - * (index < 0 || index > size()) + * @throws ArrayIndexOutOfBoundsException if the index is out of range + * ({@code index < 0 || index > size()}) * @since 1.2 */ public void add(int index, E element) { @@ -776,8 +793,8 @@ public class Vector * Shifts any subsequent elements to the left (subtracts one from their * indices). Returns the element that was removed from the Vector. * - * @exception ArrayIndexOutOfBoundsException index out of range (index - * < 0 || index >= size()) + * @throws ArrayIndexOutOfBoundsException if the index is out of range + * ({@code index < 0 || index >= size()}) * @param index the index of the element to be removed * @return element that was removed * @since 1.2 @@ -786,7 +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) @@ -794,7 +811,7 @@ public class Vector numMoved); elementData[--elementCount] = null; // Let gc do its work - return (E)oldValue; + return oldValue; } /** @@ -832,7 +849,7 @@ public class Vector * specified Collection is this Vector, and this Vector is nonempty.) * * @param c elements to be inserted into this Vector - * @return true if this Vector changed as a result of the call + * @return {@code true} if this Vector changed as a result of the call * @throws NullPointerException if the specified collection is null * @since 1.2 */ @@ -895,9 +912,9 @@ public class Vector * @param index index at which to insert the first element from the * specified collection * @param c elements to be inserted into this Vector - * @return true if this Vector changed as a result of the call - * @exception ArrayIndexOutOfBoundsException index out of range (index - * < 0 || index > size()) + * @return {@code true} if this Vector changed as a result of the call + * @throws ArrayIndexOutOfBoundsException if the index is out of range + * ({@code index < 0 || index > size()}) * @throws NullPointerException if the specified collection is null * @since 1.2 */ @@ -924,9 +941,9 @@ public class Vector * Compares the specified Object with this Vector for equality. Returns * true if and only if the specified Object is also a List, both Lists * have the same size, and all corresponding pairs of elements in the two - * Lists are equal. (Two elements e1 and - * e2 are equal if (e1==null ? e2==null : - * e1.equals(e2)).) In other words, two Lists are defined to be + * Lists are equal. (Two elements {@code e1} and + * {@code e2} are equal if {@code (e1==null ? e2==null : + * e1.equals(e2))}.) In other words, two Lists are defined to be * equal if they contain the same elements in the same order. * * @param o the Object to be compared for equality with this Vector @@ -952,14 +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. + * + *

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 index of first element to be removed - * @param toIndex index after last element to be removed + * @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++; @@ -974,7 +1027,7 @@ public class Vector } /** - * Save the state of the Vector instance to a stream (that + * Save the state of the {@code Vector} instance to a stream (that * is, serialize it). This method is present merely for synchronization. * It just calls the default writeObject method. */ @@ -985,87 +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 perfroms 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() { @@ -1076,383 +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 endpoint index value out of range - * (fromIndex < 0 || toIndex > size) - * @throws IllegalArgumentException endpoint indices out of order - * (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(); - } - } - } - } } - - -