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Diffstat (limited to 'java/util/concurrent/CopyOnWriteArrayList.java')
| -rw-r--r-- | java/util/concurrent/CopyOnWriteArrayList.java | 490 |
1 files changed, 490 insertions, 0 deletions
diff --git a/java/util/concurrent/CopyOnWriteArrayList.java b/java/util/concurrent/CopyOnWriteArrayList.java new file mode 100644 index 000000000..ec2c90cc1 --- /dev/null +++ b/java/util/concurrent/CopyOnWriteArrayList.java @@ -0,0 +1,490 @@ +/* CopyOnWriteArrayList.java + Copyright (C) 2006 Free Software Foundation + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + +package java.util.concurrent; + +import java.io.IOException; +import java.io.ObjectInputStream; +import java.io.ObjectOutputStream; +import java.io.Serializable; +import java.lang.reflect.Array; +import java.util.AbstractList; +import java.util.Collection; +import java.util.Iterator; +import java.util.List; +import java.util.RandomAccess; + +/** @since 1.5 */ +public class CopyOnWriteArrayList<E> extends AbstractList<E> implements + List<E>, RandomAccess, Cloneable, Serializable +{ + /** + * Where the data is stored. + */ + private transient E[] data; + + /** + * Construct a new ArrayList with the default capacity (16). + */ + public CopyOnWriteArrayList() + { + data = (E[]) new Object[0]; + } + + /** + * Construct a new ArrayList, and initialize it with the elements in the + * supplied Collection. The initial capacity is 110% of the Collection's size. + * + * @param c + * the collection whose elements will initialize this list + * @throws NullPointerException + * if c is null + */ + public CopyOnWriteArrayList(Collection< ? extends E> c) + { + // FIXME ... correct? use c.toArray() + data = (E[]) new Object[c.size()]; + int index = 0; + for (E value : c) + data[index++] = value; + } + + /** + * Construct a new ArrayList, and initialize it with the elements in the + * supplied array. + * + * @param array + * the array used to initialize this list + * @throws NullPointerException + * if array is null + */ + public CopyOnWriteArrayList(E[] array) + { + data = array.clone(); + } + + /** + * Returns the number of elements in this list. + * + * @return the list size + */ + public int size() + { + return data.length; + } + + /** + * Checks if the list is empty. + * + * @return true if there are no elements + */ + public boolean isEmpty() + { + return data.length == 0; + } + + /** + * Returns true iff element is in this ArrayList. + * + * @param e + * the element whose inclusion in the List is being tested + * @return true if the list contains e + */ + public boolean contains(Object e) + { + return indexOf(e) != -1; + } + + /** + * Returns the lowest index at which element appears in this List, or -1 if it + * does not appear. + * + * @param e + * the element whose inclusion in the List is being tested + * @return the index where e was found + */ + public int indexOf(Object e) + { + E[] data = this.data; + for (int i = 0; i < data.length; i++) + if (equals(e, data[i])) + return i; + return -1; + } + + /** + * Return the lowest index greater equal <code>index</code> at which + * <code>e</code> appears in this List, or -1 if it does not + * appear. + * + * @param e the element whose inclusion in the list is being tested + * @param index the index at which the search begins + * @return the index where <code>e</code> was found + */ + public int indexOf(E e, int index) + { + E[] data = this.data; + + for (int i = index; i < data.length; i++) + if (equals(e, data[i])) + return i; + return -1; + } + + /** + * Returns the highest index at which element appears in this List, or -1 if + * it does not appear. + * + * @param e + * the element whose inclusion in the List is being tested + * @return the index where e was found + */ + public int lastIndexOf(Object e) + { + E[] data = this.data; + for (int i = data.length - 1; i >= 0; i--) + if (equals(e, data[i])) + return i; + return -1; + } + + /** + * Returns the highest index lesser equal <code>index</code> at + * which <code>e</code> appears in this List, or -1 if it does not + * appear. + * + * @param e the element whose inclusion in the list is being tested + * @param index the index at which the search begins + * @return the index where <code>e</code> was found + */ + public int lastIndexOf(E e, int index) + { + E[] data = this.data; + + for (int i = index; i >= 0; i--) + if (equals(e, data[i])) + return i; + return -1; + } + + /** + * Creates a shallow copy of this ArrayList (elements are not cloned). + * + * @return the cloned object + */ + public Object clone() + { + CopyOnWriteArrayList<E> clone = null; + try + { + clone = (CopyOnWriteArrayList<E>) super.clone(); + clone.data = (E[]) data.clone(); + } + catch (CloneNotSupportedException e) + { + // Impossible to get here. + } + return clone; + } + + /** + * Returns an Object array containing all of the elements in this ArrayList. + * The array is independent of this list. + * + * @return an array representation of this list + */ + public Object[] toArray() + { + E[] data = this.data; + E[] array = (E[]) new Object[data.length]; + System.arraycopy(data, 0, array, 0, data.length); + return array; + } + + /** + * Returns an Array whose component type is the runtime component type of the + * passed-in Array. The returned Array is populated with all of the elements + * in this ArrayList. If the passed-in Array is not large enough to store all + * of the elements in this List, a new Array will be created and returned; if + * the passed-in Array is <i>larger</i> than the size of this List, then + * size() index will be set to null. + * + * @param a + * the passed-in Array + * @return an array representation of this list + * @throws ArrayStoreException + * if the runtime type of a does not allow an element in this list + * @throws NullPointerException + * if a is null + */ + public <T> T[] toArray(T[] a) + { + E[] data = this.data; + if (a.length < data.length) + a = (T[]) Array.newInstance(a.getClass().getComponentType(), data.length); + else if (a.length > data.length) + a[data.length] = null; + System.arraycopy(data, 0, a, 0, data.length); + return a; + } + + /** + * Retrieves the element at the user-supplied index. + * + * @param index + * the index of the element we are fetching + * @throws IndexOutOfBoundsException + * if index < 0 || index >= size() + */ + public E get(int index) + { + return data[index]; + } + + /** + * Sets the element at the specified index. The new element, e, can be an + * object of any type or null. + * + * @param index + * the index at which the element is being set + * @param e + * the element to be set + * @return the element previously at the specified index + * @throws IndexOutOfBoundsException + * if index < 0 || index >= 0 + */ + public synchronized E set(int index, E e) + { + E result = data[index]; + E[] newData = data.clone(); + newData[index] = e; + data = newData; + return result; + } + + /** + * Appends the supplied element to the end of this list. The element, e, can + * be an object of any type or null. + * + * @param e + * the element to be appended to this list + * @return true, the add will always succeed + */ + public synchronized boolean add(E e) + { + E[] data = this.data; + E[] newData = (E[]) new Object[data.length + 1]; + System.arraycopy(data, 0, newData, 0, data.length); + newData[data.length] = e; + this.data = newData; + return true; + } + + /** + * Adds the supplied element at the specified index, shifting all elements + * currently at that index or higher one to the right. The element, e, can be + * an object of any type or null. + * + * @param index + * the index at which the element is being added + * @param e + * the item being added + * @throws IndexOutOfBoundsException + * if index < 0 || index > size() + */ + public synchronized void add(int index, E e) + { + E[] data = this.data; + E[] newData = (E[]) new Object[data.length + 1]; + System.arraycopy(data, 0, newData, 0, index); + newData[index] = e; + System.arraycopy(data, index, newData, index + 1, data.length - index); + this.data = newData; + } + + /** + * Removes the element at the user-supplied index. + * + * @param index + * the index of the element to be removed + * @return the removed Object + * @throws IndexOutOfBoundsException + * if index < 0 || index >= size() + */ + public synchronized E remove(int index) + { + E[] data = this.data; + E[] newData = (E[]) new Object[data.length - 1]; + System.arraycopy(data, 0, newData, 0, index - 1); + System.arraycopy(data, index + 1, newData, index, + data.length - index - 1); + E r = data[index]; + this.data = newData; + return r; + } + + /** + * Removes all elements from this List + */ + public synchronized void clear() + { + data = (E[]) new Object[0]; + } + + /** + * Add each element in the supplied Collection to this List. It is undefined + * what happens if you modify the list while this is taking place; for + * example, if the collection contains this list. c can contain objects of any + * type, as well as null values. + * + * @param c + * a Collection containing elements to be added to this List + * @return true if the list was modified, in other words c is not empty + * @throws NullPointerException + * if c is null + */ + public synchronized boolean addAll(Collection< ? extends E> c) + { + return addAll(data.length, c); + } + + /** + * Add all elements in the supplied collection, inserting them beginning at + * the specified index. c can contain objects of any type, as well as null + * values. + * + * @param index + * the index at which the elements will be inserted + * @param c + * the Collection containing the elements to be inserted + * @throws IndexOutOfBoundsException + * if index < 0 || index > 0 + * @throws NullPointerException + * if c is null + */ + public synchronized boolean addAll(int index, Collection< ? extends E> c) + { + E[] data = this.data; + Iterator<? extends E> itr = c.iterator(); + int csize = c.size(); + if (csize == 0) + return false; + + E[] newData = (E[]) new Object[data.length + csize]; + System.arraycopy(data, 0, newData, 0, data.length); + int end = data.length; + for (E value : c) + newData[end++] = value; + this.data = newData; + return true; + } + + public synchronized boolean addIfAbsent(E val) + { + if (contains(val)) + return false; + add(val); + return true; + } + + public synchronized int addAllAbsent(Collection<? extends E> c) + { + int result = 0; + for (E val : c) + { + if (addIfAbsent(val)) + ++result; + } + return result; + } + + /** + * Serializes this object to the given stream. + * + * @param s + * the stream to write to + * @throws IOException + * if the underlying stream fails + * @serialData the size field (int), the length of the backing array (int), + * followed by its elements (Objects) in proper order. + */ + private void writeObject(ObjectOutputStream s) throws IOException + { + // The 'size' field. + s.defaultWriteObject(); + // We serialize unused list entries to preserve capacity. + int len = data.length; + s.writeInt(len); + // it would be more efficient to just write "size" items, + // this need readObject read "size" items too. + for (int i = 0; i < data.length; i++) + s.writeObject(data[i]); + } + + /** + * Deserializes this object from the given stream. + * + * @param s + * the stream to read from + * @throws ClassNotFoundException + * if the underlying stream fails + * @throws IOException + * if the underlying stream fails + * @serialData the size field (int), the length of the backing array (int), + * followed by its elements (Objects) in proper order. + */ + private void readObject(ObjectInputStream s) throws IOException, + ClassNotFoundException + { + // the `size' field. + s.defaultReadObject(); + int capacity = s.readInt(); + data = (E[]) new Object[capacity]; + for (int i = 0; i < capacity; i++) + data[i] = (E) s.readObject(); + } + + static final boolean equals(Object o1, Object o2) + { + return o1 == null ? o2 == null : o1.equals(o2); + } + + Object[] getArray() + { + return data; + } +} |