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/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package java.util;

import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.lang.reflect.Array;

/**
 * Vector is an implementation of {@link List}, backed by an array and synchronized.
 * All optional operations including adding, removing, and replacing elements are supported.
 *
 * 

All elements are permitted, including null. * *

This class is equivalent to {@link ArrayList} with synchronized operations. This has a * performance cost, and the synchronization is not necessarily meaningful to your application: * synchronizing each call to {@code get}, for example, is not equivalent to synchronizing on the * list and iterating over it (which is probably what you intended). If you do need very highly * concurrent access, you should also consider {@link java.util.concurrent.CopyOnWriteArrayList}. * * @param The element type of this list. */ public class Vector extends AbstractList implements List, RandomAccess, Cloneable, Serializable { private static final long serialVersionUID = -2767605614048989439L; /** * The number of elements or the size of the vector. */ protected int elementCount; /** * The elements of the vector. */ protected Object[] elementData; /** * How many elements should be added to the vector when it is detected that * it needs to grow to accommodate extra entries. If this value is zero or * negative the size will be doubled if an increase is needed. */ protected int capacityIncrement; private static final int DEFAULT_SIZE = 10; /** * Constructs a new vector using the default capacity. */ public Vector() { this(DEFAULT_SIZE, 0); } /** * Constructs a new vector using the specified capacity. * * @param capacity * the initial capacity of the new vector. * @throws IllegalArgumentException * if {@code capacity} is negative. */ public Vector(int capacity) { this(capacity, 0); } /** * Constructs a new vector using the specified capacity and capacity * increment. * * @param capacity * the initial capacity of the new vector. * @param capacityIncrement * the amount to increase the capacity when this vector is full. * @throws IllegalArgumentException * if {@code capacity} is negative. */ public Vector(int capacity, int capacityIncrement) { if (capacity < 0) { throw new IllegalArgumentException("capacity < 0: " + capacity); } elementData = newElementArray(capacity); elementCount = 0; this.capacityIncrement = capacityIncrement; } /** * Constructs a new instance of {@code Vector} containing the elements in * {@code collection}. The order of the elements in the new {@code Vector} * is dependent on the iteration order of the seed collection. * * @param collection * the collection of elements to add. */ public Vector(Collection collection) { this(collection.size(), 0); Iterator it = collection.iterator(); while (it.hasNext()) { elementData[elementCount++] = it.next(); } } @SuppressWarnings("unchecked") private E[] newElementArray(int size) { return (E[]) new Object[size]; } /** * Adds the specified object into this vector at the specified location. The * object is inserted before any element with the same or a higher index * increasing their index by 1. If the location is equal to the size of this * vector, the object is added at the end. * * @param location * the index at which to insert the element. * @param object * the object to insert in this vector. * @throws ArrayIndexOutOfBoundsException * if {@code location < 0 || location > size()}. * @see #addElement * @see #size */ @Override public void add(int location, E object) { insertElementAt(object, location); } /** * Adds the specified object at the end of this vector. * * @param object * the object to add to the vector. * @return {@code true} */ @Override public synchronized boolean add(E object) { if (elementCount == elementData.length) { growByOne(); } elementData[elementCount++] = object; modCount++; return true; } /** * Inserts the objects in the specified collection at the specified location * in this vector. The objects are inserted in the order in which they are * returned from the Collection iterator. The elements with an index equal * or higher than {@code location} have their index increased by the size of * the added collection. * * @param location * the location to insert the objects. * @param collection * the collection of objects. * @return {@code true} if this vector is modified, {@code false} otherwise. * @throws ArrayIndexOutOfBoundsException * if {@code location < 0} or {@code location > size()}. */ @Override public synchronized boolean addAll(int location, Collection collection) { if (location >= 0 && location <= elementCount) { int size = collection.size(); if (size == 0) { return false; } int required = size - (elementData.length - elementCount); if (required > 0) { growBy(required); } int count = elementCount - location; if (count > 0) { System.arraycopy(elementData, location, elementData, location + size, count); } Iterator it = collection.iterator(); while (it.hasNext()) { elementData[location++] = it.next(); } elementCount += size; modCount++; return true; } throw arrayIndexOutOfBoundsException(location, elementCount); } /** * Adds the objects in the specified collection to the end of this vector. * * @param collection * the collection of objects. * @return {@code true} if this vector is modified, {@code false} otherwise. */ @Override public synchronized boolean addAll(Collection collection) { return addAll(elementCount, collection); } /** * Adds the specified object at the end of this vector. * * @param object * the object to add to the vector. */ public synchronized void addElement(E object) { if (elementCount == elementData.length) { growByOne(); } elementData[elementCount++] = object; modCount++; } /** * Returns the number of elements this vector can hold without growing. * * @return the capacity of this vector. * @see #ensureCapacity * @see #size */ public synchronized int capacity() { return elementData.length; } /** * Removes all elements from this vector, leaving it empty. * * @see #isEmpty * @see #size */ @Override public void clear() { removeAllElements(); } /** * Returns a new vector with the same elements, size, capacity and capacity * increment as this vector. * * @return a shallow copy of this vector. * @see java.lang.Cloneable */ @Override @SuppressWarnings("unchecked") public synchronized Object clone() { try { Vector vector = (Vector) super.clone(); vector.elementData = elementData.clone(); return vector; } catch (CloneNotSupportedException e) { throw new AssertionError(e); } } /** * Searches this vector for the specified object. * * @param object * the object to look for in this vector. * @return {@code true} if object is an element of this vector, * {@code false} otherwise. * @see #indexOf(Object) * @see #indexOf(Object, int) * @see java.lang.Object#equals */ @Override public boolean contains(Object object) { return indexOf(object, 0) != -1; } /** * Searches this vector for all objects in the specified collection. * * @param collection * the collection of objects. * @return {@code true} if all objects in the specified collection are * elements of this vector, {@code false} otherwise. */ @Override public synchronized boolean containsAll(Collection collection) { return super.containsAll(collection); } /** * Attempts to copy elements contained by this {@code Vector} into the * corresponding elements of the supplied {@code Object} array. * * @param elements * the {@code Object} array into which the elements of this * vector are copied. * @throws IndexOutOfBoundsException * if {@code elements} is not big enough. * @see #clone */ public synchronized void copyInto(Object[] elements) { System.arraycopy(elementData, 0, elements, 0, elementCount); } /** * Returns the element at the specified location in this vector. * * @param location * the index of the element to return in this vector. * @return the element at the specified location. * @throws ArrayIndexOutOfBoundsException * if {@code location < 0 || location >= size()}. * @see #size */ @SuppressWarnings("unchecked") public synchronized E elementAt(int location) { if (location < elementCount) { return (E) elementData[location]; } throw arrayIndexOutOfBoundsException(location, elementCount); } /** * Returns an enumeration on the elements of this vector. The results of the * enumeration may be affected if the contents of this vector is modified. * * @return an enumeration of the elements of this vector. * @see #elementAt * @see Enumeration */ public Enumeration elements() { return new Enumeration() { int pos = 0; public boolean hasMoreElements() { return pos < elementCount; } @SuppressWarnings("unchecked") public E nextElement() { synchronized (Vector.this) { if (pos < elementCount) { return (E) elementData[pos++]; } } throw new NoSuchElementException(); } }; } /** * Ensures that this vector can hold the specified number of elements * without growing. * * @param minimumCapacity * the minimum number of elements that this vector will hold * before growing. * @see #capacity */ public synchronized void ensureCapacity(int minimumCapacity) { if (elementData.length < minimumCapacity) { int next = (capacityIncrement <= 0 ? elementData.length : capacityIncrement) + elementData.length; grow(minimumCapacity > next ? minimumCapacity : next); } } /** * Compares the specified object to this vector and returns if they are * equal. The object must be a List which contains the same objects in the * same order. * * @param object * the object to compare with this object * @return {@code true} if the specified object is equal to this vector, * {@code false} otherwise. * @see #hashCode */ @Override public synchronized boolean equals(Object object) { if (this == object) { return true; } if (object instanceof List) { List list = (List) object; if (list.size() != elementCount) { return false; } int index = 0; Iterator it = list.iterator(); while (it.hasNext()) { Object e1 = elementData[index++], e2 = it.next(); if (!(e1 == null ? e2 == null : e1.equals(e2))) { return false; } } return true; } return false; } /** * Returns the first element in this vector. * * @return the element at the first position. * @throws NoSuchElementException * if this vector is empty. * @see #elementAt * @see #lastElement * @see #size */ @SuppressWarnings("unchecked") public synchronized E firstElement() { if (elementCount > 0) { return (E) elementData[0]; } throw new NoSuchElementException(); } /** * Returns the element at the specified location in this vector. * * @param location * the index of the element to return in this vector. * @return the element at the specified location. * @throws ArrayIndexOutOfBoundsException * if {@code location < 0 || location >= size()}. * @see #size */ @Override public E get(int location) { return elementAt(location); } private void grow(int newCapacity) { E[] newData = newElementArray(newCapacity); // Assumes elementCount is <= newCapacity // assert elementCount <= newCapacity; System.arraycopy(elementData, 0, newData, 0, elementCount); elementData = newData; } /** * JIT optimization */ private void growByOne() { int adding = 0; if (capacityIncrement <= 0) { if ((adding = elementData.length) == 0) { adding = 1; } } else { adding = capacityIncrement; } E[] newData = newElementArray(elementData.length + adding); System.arraycopy(elementData, 0, newData, 0, elementCount); elementData = newData; } private void growBy(int required) { int adding = 0; if (capacityIncrement <= 0) { if ((adding = elementData.length) == 0) { adding = required; } while (adding < required) { adding += adding; } } else { adding = (required / capacityIncrement) * capacityIncrement; if (adding < required) { adding += capacityIncrement; } } E[] newData = newElementArray(elementData.length + adding); System.arraycopy(elementData, 0, newData, 0, elementCount); elementData = newData; } /** * Returns an integer hash code for the receiver. Objects which are equal * return the same value for this method. * * @return the receiver's hash. * @see #equals */ @Override public synchronized int hashCode() { int result = 1; for (int i = 0; i < elementCount; i++) { result = (31 * result) + (elementData[i] == null ? 0 : elementData[i].hashCode()); } return result; } /** * Searches in this vector for the index of the specified object. The search * for the object starts at the beginning and moves towards the end of this * vector. * * @param object * the object to find in this vector. * @return the index in this vector of the specified element, -1 if the * element isn't found. * @see #contains * @see #lastIndexOf(Object) * @see #lastIndexOf(Object, int) */ @Override public int indexOf(Object object) { return indexOf(object, 0); } /** * Searches in this vector for the index of the specified object. The search * for the object starts at the specified location and moves towards the end * of this vector. * * @param object * the object to find in this vector. * @param location * the index at which to start searching. * @return the index in this vector of the specified element, -1 if the * element isn't found. * @throws ArrayIndexOutOfBoundsException * if {@code location < 0}. * @see #contains * @see #lastIndexOf(Object) * @see #lastIndexOf(Object, int) */ public synchronized int indexOf(Object object, int location) { if (object != null) { for (int i = location; i < elementCount; i++) { if (object.equals(elementData[i])) { return i; } } } else { for (int i = location; i < elementCount; i++) { if (elementData[i] == null) { return i; } } } return -1; } /** * Inserts the specified object into this vector at the specified location. * This object is inserted before any previous element at the specified * location. All elements with an index equal or greater than * {@code location} have their index increased by 1. If the location is * equal to the size of this vector, the object is added at the end. * * @param object * the object to insert in this vector. * @param location * the index at which to insert the element. * @throws ArrayIndexOutOfBoundsException * if {@code location < 0 || location > size()}. * @see #addElement * @see #size */ public synchronized void insertElementAt(E object, int location) { if (location >= 0 && location <= elementCount) { if (elementCount == elementData.length) { growByOne(); } int count = elementCount - location; if (count > 0) { System.arraycopy(elementData, location, elementData, location + 1, count); } elementData[location] = object; elementCount++; modCount++; } else { throw arrayIndexOutOfBoundsException(location, elementCount); } } /** * Returns if this vector has no elements, a size of zero. * * @return {@code true} if this vector has no elements, {@code false} * otherwise. * @see #size */ @Override public synchronized boolean isEmpty() { return elementCount == 0; } /** * Returns the last element in this vector. * * @return the element at the last position. * @throws NoSuchElementException * if this vector is empty. * @see #elementAt * @see #firstElement * @see #size */ @SuppressWarnings("unchecked") public synchronized E lastElement() { try { return (E) elementData[elementCount - 1]; } catch (IndexOutOfBoundsException e) { throw new NoSuchElementException(); } } /** * Searches in this vector for the index of the specified object. The search * for the object starts at the end and moves towards the start of this * vector. * * @param object * the object to find in this vector. * @return the index in this vector of the specified element, -1 if the * element isn't found. * @see #contains * @see #indexOf(Object) * @see #indexOf(Object, int) */ @Override public synchronized int lastIndexOf(Object object) { return lastIndexOf(object, elementCount - 1); } /** * Searches in this vector for the index of the specified object. The search * for the object starts at the specified location and moves towards the * start of this vector. * * @param object * the object to find in this vector. * @param location * the index at which to start searching. * @return the index in this vector of the specified element, -1 if the * element isn't found. * @throws ArrayIndexOutOfBoundsException * if {@code location >= size()}. * @see #contains * @see #indexOf(Object) * @see #indexOf(Object, int) */ public synchronized int lastIndexOf(Object object, int location) { if (location < elementCount) { if (object != null) { for (int i = location; i >= 0; i--) { if (object.equals(elementData[i])) { return i; } } } else { for (int i = location; i >= 0; i--) { if (elementData[i] == null) { return i; } } } return -1; } throw arrayIndexOutOfBoundsException(location, elementCount); } /** * Removes the object at the specified location from this vector. All * elements with an index bigger than {@code location} have their index * decreased by 1. * * @param location * the index of the object to remove. * @return the removed object. * @throws IndexOutOfBoundsException * if {@code location < 0 || location >= size()}. */ @SuppressWarnings("unchecked") @Override public synchronized E remove(int location) { if (location < elementCount) { E result = (E) elementData[location]; elementCount--; int size = elementCount - location; if (size > 0) { System.arraycopy(elementData, location + 1, elementData, location, size); } elementData[elementCount] = null; modCount++; return result; } throw arrayIndexOutOfBoundsException(location, elementCount); } /** * Removes the first occurrence, starting at the beginning and moving * towards the end, of the specified object from this vector. All elements * with an index bigger than the element that gets removed have their index * decreased by 1. * * @param object * the object to remove from this vector. * @return {@code true} if the specified object was found, {@code false} * otherwise. * @see #removeAllElements * @see #removeElementAt * @see #size */ @Override public boolean remove(Object object) { return removeElement(object); } /** * Removes all occurrences in this vector of each object in the specified * Collection. * * @param collection * the collection of objects to remove. * @return {@code true} if this vector is modified, {@code false} otherwise. * @see #remove(Object) * @see #contains(Object) */ @Override public synchronized boolean removeAll(Collection collection) { return super.removeAll(collection); } /** * Removes all elements from this vector, leaving the size zero and the * capacity unchanged. * * @see #isEmpty * @see #size */ public synchronized void removeAllElements() { for (int i = 0; i < elementCount; i++) { elementData[i] = null; } modCount++; elementCount = 0; } /** * Removes the first occurrence, starting at the beginning and moving * towards the end, of the specified object from this vector. All elements * with an index bigger than the element that gets removed have their index * decreased by 1. * * @param object * the object to remove from this vector. * @return {@code true} if the specified object was found, {@code false} * otherwise. * @see #removeAllElements * @see #removeElementAt * @see #size */ public synchronized boolean removeElement(Object object) { int index; if ((index = indexOf(object, 0)) == -1) { return false; } removeElementAt(index); return true; } /** * Removes the element found at index position {@code location} from * this {@code Vector}. All elements with an index bigger than * {@code location} have their index decreased by 1. * * @param location * the index of the element to remove. * @throws ArrayIndexOutOfBoundsException * if {@code location < 0 || location >= size()}. * @see #removeElement * @see #removeAllElements * @see #size */ public synchronized void removeElementAt(int location) { if (location >= 0 && location < elementCount) { elementCount--; int size = elementCount - location; if (size > 0) { System.arraycopy(elementData, location + 1, elementData, location, size); } elementData[elementCount] = null; modCount++; } else { throw arrayIndexOutOfBoundsException(location, elementCount); } } /** * Removes the objects in the specified range from the start to the, but not * including, end index. All elements with an index bigger than or equal to * {@code end} have their index decreased by {@code end - start}. * * @param start * the index at which to start removing. * @param end * the index one past the end of the range to remove. * @throws IndexOutOfBoundsException * if {@code start < 0, start > end} or * {@code end > size()}. */ @Override protected void removeRange(int start, int end) { if (start >= 0 && start <= end && end <= elementCount) { if (start == end) { return; } if (end != elementCount) { System.arraycopy(elementData, end, elementData, start, elementCount - end); int newCount = elementCount - (end - start); Arrays.fill(elementData, newCount, elementCount, null); elementCount = newCount; } else { Arrays.fill(elementData, start, elementCount, null); elementCount = start; } modCount++; } else { throw new IndexOutOfBoundsException(); } } /** * Removes all objects from this vector that are not contained in the * specified collection. * * @param collection * the collection of objects to retain. * @return {@code true} if this vector is modified, {@code false} otherwise. * @see #remove(Object) */ @Override public synchronized boolean retainAll(Collection collection) { return super.retainAll(collection); } /** * Replaces the element at the specified location in this vector with the * specified object. * * @param location * the index at which to put the specified object. * @param object * the object to add to this vector. * @return the previous element at the location. * @throws ArrayIndexOutOfBoundsException * if {@code location < 0 || location >= size()}. * @see #size */ @SuppressWarnings("unchecked") @Override public synchronized E set(int location, E object) { if (location < elementCount) { E result = (E) elementData[location]; elementData[location] = object; return result; } throw arrayIndexOutOfBoundsException(location, elementCount); } /** * Replaces the element at the specified location in this vector with the * specified object. * * @param object * the object to add to this vector. * @param location * the index at which to put the specified object. * @throws ArrayIndexOutOfBoundsException * if {@code location < 0 || location >= size()}. * @see #size */ public synchronized void setElementAt(E object, int location) { if (location < elementCount) { elementData[location] = object; } else { throw arrayIndexOutOfBoundsException(location, elementCount); } } /** * This method was extracted to encourage VM to inline callers. * TODO: when we have a VM that can actually inline, move the test in here too! */ private static ArrayIndexOutOfBoundsException arrayIndexOutOfBoundsException(int index, int size) { throw new ArrayIndexOutOfBoundsException(size, index); } /** * Sets the size of this vector to the specified size. If there are more * than length elements in this vector, the elements at end are lost. If * there are less than length elements in the vector, the additional * elements contain null. * * @param length * the new size of this vector. * @see #size */ public synchronized void setSize(int length) { if (length == elementCount) { return; } ensureCapacity(length); if (elementCount > length) { Arrays.fill(elementData, length, elementCount, null); } elementCount = length; modCount++; } /** * Returns the number of elements in this vector. * * @return the number of elements in this vector. * @see #elementCount * @see #lastElement */ @Override public synchronized int size() { return elementCount; } /** * Returns a List of the specified portion of this vector from the start * index to one less than the end index. The returned List is backed by this * vector so changes to one are reflected by the other. * * @param start * the index at which to start the sublist. * @param end * the index one past the end of the sublist. * @return a List of a portion of this vector. * @throws IndexOutOfBoundsException * if {@code start < 0} or {@code end > size()}. * @throws IllegalArgumentException * if {@code start > end}. */ @Override public synchronized List subList(int start, int end) { return new Collections.SynchronizedRandomAccessList(super.subList( start, end), this); } /** * Returns a new array containing all elements contained in this vector. * * @return an array of the elements from this vector. */ @Override public synchronized Object[] toArray() { Object[] result = new Object[elementCount]; System.arraycopy(elementData, 0, result, 0, elementCount); return result; } /** * Returns an array containing all elements contained in this vector. If the * specified array is large enough to hold the elements, the specified array * is used, otherwise an array of the same type is created. If the specified * array is used and is larger than this vector, the array element following * the collection elements is set to null. * * @param contents * the array to fill. * @return an array of the elements from this vector. * @throws ArrayStoreException * if the type of an element in this vector cannot be * stored in the type of the specified array. */ @Override @SuppressWarnings("unchecked") public synchronized T[] toArray(T[] contents) { if (elementCount > contents.length) { Class ct = contents.getClass().getComponentType(); contents = (T[]) Array.newInstance(ct, elementCount); } System.arraycopy(elementData, 0, contents, 0, elementCount); if (elementCount < contents.length) { contents[elementCount] = null; } return contents; } /** * Returns the string representation of this vector. * * @return the string representation of this vector. * @see #elements */ @Override public synchronized String toString() { if (elementCount == 0) { return "[]"; } int length = elementCount - 1; StringBuilder buffer = new StringBuilder(elementCount * 16); buffer.append('['); for (int i = 0; i < length; i++) { if (elementData[i] == this) { buffer.append("(this Collection)"); } else { buffer.append(elementData[i]); } buffer.append(", "); } if (elementData[length] == this) { buffer.append("(this Collection)"); } else { buffer.append(elementData[length]); } buffer.append(']'); return buffer.toString(); } /** * Sets the capacity of this vector to be the same as the size. * * @see #capacity * @see #ensureCapacity * @see #size */ public synchronized void trimToSize() { if (elementData.length != elementCount) { grow(elementCount); } } private synchronized void writeObject(ObjectOutputStream stream) throws IOException { stream.defaultWriteObject(); } }





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