--- jsr166/src/main/java/util/ArrayList.java 2007/09/11 15:38:02 1.25
+++ jsr166/src/main/java/util/ArrayList.java 2016/12/05 00:08:01 1.47
@@ -1,12 +1,12 @@
/*
- * Copyright 1997-2007 Sun Microsystems, Inc. All Rights Reserved.
+ * Copyright (c) 1997, 2016, Oracle and/or its affiliates. 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
* under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation. Sun designates this
+ * published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
- * by Sun in the LICENSE file that accompanied this code.
+ * by Oracle 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
@@ -18,41 +18,45 @@
* 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.
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
*/
package java.util;
+import java.util.function.Consumer;
+import java.util.function.Predicate;
+import java.util.function.UnaryOperator;
+
/**
- * Resizable-array implementation of the List interface. Implements
+ * Resizable-array implementation of the {@code List} interface. Implements
* all optional list operations, and permits all elements, including
- * null. In addition to implementing the List interface,
+ * {@code null}. In addition to implementing the {@code List} interface,
* this class provides methods to manipulate the size of the array that is
* used internally to store the list. (This class is roughly equivalent to
- * Vector, except that it is unsynchronized.)
+ * {@code Vector}, except that it is unsynchronized.)
*
- *
The size, isEmpty, get, set,
- * iterator, and listIterator operations run in constant
- * time. The add operation runs in amortized constant time,
+ *
The {@code size}, {@code isEmpty}, {@code get}, {@code set},
+ * {@code iterator}, and {@code listIterator} operations run in constant
+ * time. The {@code add} operation runs in amortized constant time,
* that is, adding n elements requires O(n) time. All of the other operations
* run in linear time (roughly speaking). The constant factor is low compared
- * to that for the LinkedList implementation.
+ * to that for the {@code LinkedList} implementation.
*
- *
Each ArrayList instance has a capacity. The capacity is
+ *
Each {@code ArrayList} instance has a capacity. The capacity is
* the size of the array used to store the elements in the list. It is always
* at least as large as the list size. As elements are added to an ArrayList,
* its capacity grows automatically. The details of the growth policy are not
* specified beyond the fact that adding an element has constant amortized
* time cost.
*
- *
An application can increase the capacity of an ArrayList instance
- * before adding a large number of elements using the ensureCapacity
+ *
An application can increase the capacity of an {@code ArrayList} instance
+ * before adding a large number of elements using the {@code ensureCapacity}
* operation. This may reduce the amount of incremental reallocation.
*
*
Note that this implementation is not synchronized.
- * If multiple threads access an ArrayList instance concurrently,
+ * If multiple threads access an {@code ArrayList} instance concurrently,
* and at least one of the threads modifies the list structurally, it
* must be synchronized externally. (A structural modification is
* any operation that adds or deletes one or more elements, or explicitly
@@ -66,7 +70,7 @@ package java.util;
* unsynchronized access to the list:
* List list = Collections.synchronizedList(new ArrayList(...));
*
- *
+ *
* The iterators returned by this class's {@link #iterator() iterator} and
* {@link #listIterator(int) listIterator} methods are fail-fast:
* if the list is structurally modified at any time after the iterator is
@@ -90,26 +94,45 @@ package java.util;
*
* Java Collections Framework.
*
+ * @param the type of elements in this list
+ *
* @author Josh Bloch
* @author Neal Gafter
- * @version %I%, %G%
- * @see Collection
- * @see List
- * @see LinkedList
- * @see Vector
+ * @see Collection
+ * @see List
+ * @see LinkedList
+ * @see Vector
* @since 1.2
*/
-
public class ArrayList extends AbstractList
implements List, RandomAccess, Cloneable, java.io.Serializable
{
private static final long serialVersionUID = 8683452581122892189L;
/**
+ * Default initial capacity.
+ */
+ private static final int DEFAULT_CAPACITY = 10;
+
+ /**
+ * Shared empty array instance used for empty instances.
+ */
+ private static final Object[] EMPTY_ELEMENTDATA = {};
+
+ /**
+ * Shared empty array instance used for default sized empty instances. We
+ * distinguish this from EMPTY_ELEMENTDATA to know how much to inflate when
+ * first element is added.
+ */
+ private static final Object[] DEFAULTCAPACITY_EMPTY_ELEMENTDATA = {};
+
+ /**
* The array buffer into which the elements of the ArrayList are stored.
- * The capacity of the ArrayList is the length of this array buffer.
+ * The capacity of the ArrayList is the length of this array buffer. Any
+ * empty ArrayList with elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA
+ * will be expanded to DEFAULT_CAPACITY when the first element is added.
*/
- private transient Object[] elementData;
+ transient Object[] elementData; // non-private to simplify nested class access
/**
* The size of the ArrayList (the number of elements it contains).
@@ -121,23 +144,26 @@ public class ArrayList extends Abstra
/**
* Constructs an empty list with the specified initial capacity.
*
- * @param initialCapacity the initial capacity of the list
- * @exception IllegalArgumentException if the specified initial capacity
- * is negative
+ * @param initialCapacity the initial capacity of the list
+ * @throws IllegalArgumentException if the specified initial capacity
+ * is negative
*/
public ArrayList(int initialCapacity) {
- super();
- if (initialCapacity < 0)
+ if (initialCapacity > 0) {
+ this.elementData = new Object[initialCapacity];
+ } else if (initialCapacity == 0) {
+ this.elementData = EMPTY_ELEMENTDATA;
+ } else {
throw new IllegalArgumentException("Illegal Capacity: "+
initialCapacity);
- this.elementData = new Object[initialCapacity];
+ }
}
/**
* Constructs an empty list with an initial capacity of ten.
*/
public ArrayList() {
- this(10);
+ this.elementData = DEFAULTCAPACITY_EMPTY_ELEMENTDATA;
}
/**
@@ -149,44 +175,103 @@ public class ArrayList extends Abstra
* @throws NullPointerException if the specified collection is null
*/
public ArrayList(Collection extends E> c) {
- elementData = c.toArray();
- size = elementData.length;
- // c.toArray might (incorrectly) not return Object[] (see 6260652)
- if (elementData.getClass() != Object[].class)
- elementData = Arrays.copyOf(elementData, size, Object[].class);
+ elementData = c.toArray();
+ if ((size = elementData.length) != 0) {
+ // defend against c.toArray (incorrectly) not returning Object[]
+ // (see e.g. https://bugs.openjdk.java.net/browse/JDK-6260652)
+ if (elementData.getClass() != Object[].class)
+ elementData = Arrays.copyOf(elementData, size, Object[].class);
+ } else {
+ // replace with empty array.
+ this.elementData = EMPTY_ELEMENTDATA;
+ }
}
/**
- * Trims the capacity of this ArrayList instance to be the
+ * Trims the capacity of this {@code ArrayList} instance to be the
* list's current size. An application can use this operation to minimize
- * the storage of an ArrayList instance.
+ * the storage of an {@code ArrayList} instance.
*/
public void trimToSize() {
- modCount++;
- int oldCapacity = elementData.length;
- if (size < oldCapacity) {
- elementData = Arrays.copyOf(elementData, size);
- }
+ modCount++;
+ if (size < elementData.length) {
+ elementData = (size == 0)
+ ? EMPTY_ELEMENTDATA
+ : Arrays.copyOf(elementData, size);
+ }
}
/**
- * Increases the capacity of this ArrayList instance, if
+ * Increases the capacity of this {@code ArrayList} instance, if
* necessary, to ensure that it can hold at least the number of elements
* specified by the minimum capacity argument.
*
- * @param minCapacity the desired minimum capacity
+ * @param minCapacity the desired minimum capacity
*/
public void ensureCapacity(int minCapacity) {
- modCount++;
- int oldCapacity = elementData.length;
- if (minCapacity > oldCapacity) {
- Object oldData[] = elementData;
- int newCapacity = (oldCapacity * 3)/2 + 1;
- if (newCapacity < minCapacity)
- newCapacity = minCapacity;
- // minCapacity is usually close to size, so this is a win:
- elementData = Arrays.copyOf(elementData, newCapacity);
- }
+ if (minCapacity > elementData.length
+ && !(elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA
+ && minCapacity <= DEFAULT_CAPACITY)) {
+ modCount++;
+ grow(minCapacity);
+ }
+ }
+
+ /**
+ * The maximum size of array to allocate (unless necessary).
+ * Some VMs reserve some header words in an array.
+ * Attempts to allocate larger arrays may result in
+ * OutOfMemoryError: Requested array size exceeds VM limit
+ */
+ private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
+
+ /**
+ * Increases the capacity to ensure that it can hold at least the
+ * number of elements specified by the minimum capacity argument.
+ *
+ * @param minCapacity the desired minimum capacity
+ * @throws OutOfMemoryError if minCapacity is less than zero
+ */
+ private Object[] grow(int minCapacity) {
+ return elementData = Arrays.copyOf(elementData,
+ newCapacity(minCapacity));
+ }
+
+ private Object[] grow() {
+ return grow(size + 1);
+ }
+
+ /**
+ * Returns a capacity at least as large as the given minimum capacity.
+ * Returns the current capacity increased by 50% if that suffices.
+ * Will not return a capacity greater than MAX_ARRAY_SIZE unless
+ * the given minimum capacity is greater than MAX_ARRAY_SIZE.
+ *
+ * @param minCapacity the desired minimum capacity
+ * @throws OutOfMemoryError if minCapacity is less than zero
+ */
+ private int newCapacity(int minCapacity) {
+ // overflow-conscious code
+ int oldCapacity = elementData.length;
+ int newCapacity = oldCapacity + (oldCapacity >> 1);
+ if (newCapacity - minCapacity <= 0) {
+ if (elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA)
+ return Math.max(DEFAULT_CAPACITY, minCapacity);
+ if (minCapacity < 0) // overflow
+ throw new OutOfMemoryError();
+ return minCapacity;
+ }
+ return (newCapacity - MAX_ARRAY_SIZE <= 0)
+ ? newCapacity
+ : hugeCapacity(minCapacity);
+ }
+
+ private static int hugeCapacity(int minCapacity) {
+ if (minCapacity < 0) // overflow
+ throw new OutOfMemoryError();
+ return (minCapacity > MAX_ARRAY_SIZE)
+ ? Integer.MAX_VALUE
+ : MAX_ARRAY_SIZE;
}
/**
@@ -195,88 +280,87 @@ public class ArrayList extends Abstra
* @return the number of elements in this list
*/
public int size() {
- return size;
+ return size;
}
/**
- * Returns true if this list contains no elements.
+ * Returns {@code true} if this list contains no elements.
*
- * @return true if this list contains no elements
+ * @return {@code true} if this list contains no elements
*/
public boolean isEmpty() {
- return size == 0;
+ return size == 0;
}
/**
- * Returns true if this list contains the specified element.
- * More formally, returns true if and only if this list contains
- * at least one element e such that
- * (o==null ? e==null : o.equals(e)).
+ * Returns {@code true} if this list contains the specified element.
+ * More formally, returns {@code true} if and only if this list contains
+ * at least one element {@code e} such that
+ * {@code Objects.equals(o, e)}.
*
* @param o element whose presence in this list is to be tested
- * @return true if this list contains the specified element
+ * @return {@code true} if this list contains the specified element
*/
public boolean contains(Object o) {
- return indexOf(o) >= 0;
+ return indexOf(o) >= 0;
}
/**
* Returns the index of the first occurrence of the specified element
* in this list, or -1 if this list does not contain the element.
- * More formally, returns the lowest index i such that
- * (o==null ? get(i)==null : o.equals(get(i))),
+ * More formally, returns the lowest index {@code i} such that
+ * {@code Objects.equals(o, get(i))},
* or -1 if there is no such index.
*/
public int indexOf(Object o) {
- if (o == null) {
- for (int i = 0; i < size; i++)
- if (elementData[i]==null)
- return i;
- } else {
- for (int i = 0; i < size; i++)
- if (o.equals(elementData[i]))
- return i;
- }
- return -1;
+ if (o == null) {
+ for (int i = 0; i < size; i++)
+ if (elementData[i]==null)
+ return i;
+ } else {
+ for (int i = 0; i < size; i++)
+ if (o.equals(elementData[i]))
+ return i;
+ }
+ return -1;
}
/**
* Returns the index of the last occurrence of the specified element
* in this list, or -1 if this list does not contain the element.
- * More formally, returns the highest index i such that
- * (o==null ? get(i)==null : o.equals(get(i))),
+ * More formally, returns the highest index {@code i} such that
+ * {@code Objects.equals(o, get(i))},
* or -1 if there is no such index.
*/
public int lastIndexOf(Object o) {
- if (o == null) {
- for (int i = size-1; i >= 0; i--)
- if (elementData[i]==null)
- return i;
- } else {
- for (int i = size-1; i >= 0; i--)
- if (o.equals(elementData[i]))
- return i;
- }
- return -1;
+ if (o == null) {
+ for (int i = size-1; i >= 0; i--)
+ if (elementData[i]==null)
+ return i;
+ } else {
+ for (int i = size-1; i >= 0; i--)
+ if (o.equals(elementData[i]))
+ return i;
+ }
+ return -1;
}
/**
- * Returns a shallow copy of this ArrayList instance. (The
+ * Returns a shallow copy of this {@code ArrayList} instance. (The
* elements themselves are not copied.)
*
- * @return a clone of this ArrayList instance
+ * @return a clone of this {@code ArrayList} instance
*/
public Object clone() {
- try {
- @SuppressWarnings("unchecked")
- ArrayList v = (ArrayList) super.clone();
- v.elementData = Arrays.copyOf(elementData, size);
- v.modCount = 0;
- return v;
- } catch (CloneNotSupportedException e) {
- // this shouldn't happen, since we are Cloneable
- throw new InternalError();
- }
+ try {
+ ArrayList> v = (ArrayList>) super.clone();
+ v.elementData = Arrays.copyOf(elementData, size);
+ v.modCount = 0;
+ return v;
+ } catch (CloneNotSupportedException e) {
+ // this shouldn't happen, since we are Cloneable
+ throw new InternalError(e);
+ }
}
/**
@@ -308,7 +392,7 @@ public class ArrayList extends Abstra
* If the list fits in the specified array with room to spare
* (i.e., the array has more elements than the list), the element in
* the array immediately following the end of the collection is set to
- * null. (This is useful in determining the length of the
+ * {@code null}. (This is useful in determining the length of the
* list only if the caller knows that the list does not contain
* any null elements.)
*
@@ -326,7 +410,7 @@ public class ArrayList extends Abstra
if (a.length < size)
// Make a new array of a's runtime type, but my contents:
return (T[]) Arrays.copyOf(elementData, size, a.getClass());
- System.arraycopy(elementData, 0, a, 0, size);
+ System.arraycopy(elementData, 0, a, 0, size);
if (a.length > size)
a[size] = null;
return a;
@@ -336,7 +420,12 @@ public class ArrayList extends Abstra
@SuppressWarnings("unchecked")
E elementData(int index) {
- return (E) elementData[index];
+ return (E) elementData[index];
+ }
+
+ @SuppressWarnings("unchecked")
+ static E elementAt(Object[] es, int index) {
+ return (E) es[index];
}
/**
@@ -347,9 +436,8 @@ public class ArrayList extends Abstra
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public E get(int index) {
- rangeCheck(index);
-
- return elementData(index);
+ Objects.checkIndex(index, size);
+ return elementData(index);
}
/**
@@ -362,23 +450,34 @@ public class ArrayList extends Abstra
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public E set(int index, E element) {
- rangeCheck(index);
+ Objects.checkIndex(index, size);
+ E oldValue = elementData(index);
+ elementData[index] = element;
+ return oldValue;
+ }
- E oldValue = elementData(index);
- elementData[index] = element;
- return oldValue;
+ /**
+ * This helper method split out from add(E) to keep method
+ * bytecode size under 35 (the -XX:MaxInlineSize default value),
+ * which helps when add(E) is called in a C1-compiled loop.
+ */
+ private void add(E e, Object[] elementData, int s) {
+ if (s == elementData.length)
+ elementData = grow();
+ elementData[s] = e;
+ size = s + 1;
}
/**
* Appends the specified element to the end of this list.
*
* @param e element to be appended to this list
- * @return true (as specified by {@link Collection#add})
+ * @return {@code true} (as specified by {@link Collection#add})
*/
public boolean add(E e) {
- ensureCapacity(size + 1); // Increments modCount!!
- elementData[size++] = e;
- return true;
+ modCount++;
+ add(e, elementData, size);
+ return true;
}
/**
@@ -391,13 +490,18 @@ public class ArrayList extends Abstra
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public void add(int index, E element) {
- rangeCheckForAdd(index);
-
- ensureCapacity(size+1); // Increments modCount!!
- System.arraycopy(elementData, index, elementData, index + 1,
- size - index);
- elementData[index] = element;
- size++;
+ rangeCheckForAdd(index);
+ modCount++;
+ final int s;
+ Object[] elementData;
+ if ((s = size) == (elementData = this.elementData).length)
+ elementData = grow();
+ System.arraycopy(elementData, index,
+ elementData, index + 1,
+ s - index);
+ elementData[index] = element;
+ size = s + 1;
+ // checkInvariants();
}
/**
@@ -410,51 +514,52 @@ public class ArrayList extends Abstra
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public E remove(int index) {
- rangeCheck(index);
+ Objects.checkIndex(index, size);
- modCount++;
- E oldValue = elementData(index);
+ modCount++;
+ E oldValue = elementData(index);
- int numMoved = size - index - 1;
- if (numMoved > 0)
- System.arraycopy(elementData, index+1, elementData, index,
- numMoved);
- elementData[--size] = null; // Let gc do its work
+ int numMoved = size - index - 1;
+ if (numMoved > 0)
+ System.arraycopy(elementData, index+1, elementData, index,
+ numMoved);
+ elementData[--size] = null; // clear to let GC do its work
- return oldValue;
+ // checkInvariants();
+ return oldValue;
}
/**
* Removes the first occurrence of the specified element from this list,
* if it is present. If the list 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 an element exists). Returns true if this list
+ * {@code i} such that
+ * {@code Objects.equals(o, get(i))}
+ * (if such an element exists). Returns {@code true} if this list
* contained the specified element (or equivalently, if this list
* changed as a result of the call).
*
* @param o element to be removed from this list, if present
- * @return true if this list contained the specified element
+ * @return {@code true} if this list contained the specified element
*/
public boolean remove(Object o) {
- if (o == null) {
+ if (o == null) {
+ for (int index = 0; index < size; index++)
+ if (elementData[index] == null) {
+ fastRemove(index);
+ return true;
+ }
+ } else {
for (int index = 0; index < size; index++)
- if (elementData[index] == null) {
- fastRemove(index);
- return true;
- }
- } else {
- for (int index = 0; index < size; index++)
- if (o.equals(elementData[index])) {
- fastRemove(index);
- return true;
- }
+ if (o.equals(elementData[index])) {
+ fastRemove(index);
+ return true;
+ }
}
- return false;
+ return false;
}
- /*
+ /**
* Private remove method that skips bounds checking and does not
* return the value removed.
*/
@@ -464,7 +569,7 @@ public class ArrayList extends Abstra
if (numMoved > 0)
System.arraycopy(elementData, index+1, elementData, index,
numMoved);
- elementData[--size] = null; // Let gc do its work
+ elementData[--size] = null; // clear to let GC do its work
}
/**
@@ -472,13 +577,10 @@ public class ArrayList extends Abstra
* be empty after this call returns.
*/
public void clear() {
- modCount++;
-
- // Let gc do its work
- for (int i = 0; i < size; i++)
- elementData[i] = null;
-
- size = 0;
+ modCount++;
+ final Object[] es = elementData;
+ for (int to = size, i = size = 0; i < to; i++)
+ es[i] = null;
}
/**
@@ -491,16 +593,23 @@ public class ArrayList extends Abstra
* list is nonempty.)
*
* @param c collection containing elements to be added to this list
- * @return true if this list changed as a result of the call
+ * @return {@code true} if this list changed as a result of the call
* @throws NullPointerException if the specified collection is null
*/
public boolean addAll(Collection extends E> c) {
- Object[] a = c.toArray();
+ Object[] a = c.toArray();
+ modCount++;
int numNew = a.length;
- ensureCapacity(size + numNew); // Increments modCount
- System.arraycopy(a, 0, elementData, size, numNew);
- size += numNew;
- return numNew != 0;
+ if (numNew == 0)
+ return false;
+ Object[] elementData;
+ final int s;
+ if (numNew > (elementData = this.elementData).length - (s = size))
+ elementData = grow(s + numNew);
+ System.arraycopy(a, 0, elementData, s, numNew);
+ size = s + numNew;
+ // checkInvariants();
+ return true;
}
/**
@@ -514,25 +623,32 @@ public class ArrayList extends Abstra
* @param index index at which to insert the first element from the
* specified collection
* @param c collection containing elements to be added to this list
- * @return true if this list changed as a result of the call
+ * @return {@code true} if this list changed as a result of the call
* @throws IndexOutOfBoundsException {@inheritDoc}
* @throws NullPointerException if the specified collection is null
*/
public boolean addAll(int index, Collection extends E> c) {
- rangeCheckForAdd(index);
+ rangeCheckForAdd(index);
- Object[] a = c.toArray();
- int numNew = a.length;
- ensureCapacity(size + numNew); // Increments modCount
-
- int numMoved = size - index;
- if (numMoved > 0)
- System.arraycopy(elementData, index, elementData, index + numNew,
- numMoved);
+ Object[] a = c.toArray();
+ modCount++;
+ int numNew = a.length;
+ if (numNew == 0)
+ return false;
+ Object[] elementData;
+ final int s;
+ if (numNew > (elementData = this.elementData).length - (s = size))
+ elementData = grow(s + numNew);
+ int numMoved = s - index;
+ if (numMoved > 0)
+ System.arraycopy(elementData, index,
+ elementData, index + numNew,
+ numMoved);
System.arraycopy(a, 0, elementData, index, numNew);
- size += numNew;
- return numNew != 0;
+ size = s + numNew;
+ // checkInvariants();
+ return true;
}
/**
@@ -545,39 +661,32 @@ public class ArrayList extends Abstra
* @throws IndexOutOfBoundsException if {@code fromIndex} or
* {@code toIndex} is out of range
* ({@code fromIndex < 0 ||
- * fromIndex >= size() ||
* toIndex > size() ||
* toIndex < fromIndex})
*/
protected void removeRange(int fromIndex, int toIndex) {
- modCount++;
- int numMoved = size - toIndex;
- System.arraycopy(elementData, toIndex, elementData, fromIndex,
- numMoved);
-
- // Let gc do its work
- int newSize = size - (toIndex-fromIndex);
- while (size != newSize)
- elementData[--size] = null;
+ if (fromIndex > toIndex) {
+ throw new IndexOutOfBoundsException(
+ outOfBoundsMsg(fromIndex, toIndex));
+ }
+ modCount++;
+ shiftTailOverGap(elementData, fromIndex, toIndex);
+ // checkInvariants();
}
- /**
- * Checks if the given index is in range. If not, throws an appropriate
- * runtime exception. This method does *not* check if the index is
- * negative: It is always used immediately prior to an array access,
- * which throws an ArrayIndexOutOfBoundsException if index is negative.
- */
- private void rangeCheck(int index) {
- if (index >= size)
- throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
+ /** Erases the gap from lo to hi, by sliding down following elements. */
+ private void shiftTailOverGap(Object[] es, int lo, int hi) {
+ System.arraycopy(es, hi, es, lo, size - hi);
+ for (int to = size, i = (size -= hi - lo); i < to; i++)
+ es[i] = null;
}
/**
* A version of rangeCheck used by add and addAll.
*/
private void rangeCheckForAdd(int index) {
- if (index > size || index < 0)
- throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
+ if (index > size || index < 0)
+ throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
}
/**
@@ -586,7 +695,14 @@ public class ArrayList extends Abstra
* this "outlining" performs best with both server and client VMs.
*/
private String outOfBoundsMsg(int index) {
- return "Index: "+index+", Size: "+size;
+ return "Index: "+index+", Size: "+size;
+ }
+
+ /**
+ * A version used in checking (fromIndex > toIndex) condition
+ */
+ private static String outOfBoundsMsg(int fromIndex, int toIndex) {
+ return "From Index: " + fromIndex + " > To Index: " + toIndex;
}
/**
@@ -596,14 +712,16 @@ public class ArrayList extends Abstra
* @param c collection containing elements to be removed from this list
* @return {@code true} if this list changed as a result of the call
* @throws ClassCastException if the class of an element of this list
- * is incompatible with the specified collection (optional)
+ * is incompatible with the specified collection
+ * (optional)
* @throws NullPointerException if this list contains a null element and the
- * specified collection does not permit null elements (optional),
+ * specified collection does not permit null elements
+ * (optional),
* or if the specified collection is null
* @see Collection#contains(Object)
*/
public boolean removeAll(Collection> c) {
- return batchRemove(c, false);
+ return batchRemove(c, false, 0, size);
}
/**
@@ -614,87 +732,109 @@ public class ArrayList extends Abstra
* @param c collection containing elements to be retained in this list
* @return {@code true} if this list changed as a result of the call
* @throws ClassCastException if the class of an element of this list
- * is incompatible with the specified collection (optional)
+ * is incompatible with the specified collection
+ * (optional)
* @throws NullPointerException if this list contains a null element and the
- * specified collection does not permit null elements (optional),
+ * specified collection does not permit null elements
+ * (optional),
* or if the specified collection is null
* @see Collection#contains(Object)
*/
public boolean retainAll(Collection> c) {
- return batchRemove(c, true);
+ return batchRemove(c, true, 0, size);
}
- private boolean batchRemove(Collection> c, boolean complement) {
- final Object[] elementData = this.elementData;
- int r = 0, w = 0;
- boolean modified = false;
- try {
- for (; r < size; r++)
- if (c.contains(elementData[r]) == complement)
- elementData[w++] = elementData[r];
- } finally {
- // Preserve behavioral compatibility with AbstractCollection,
- // even if c.contains() throws.
- if (r != size) {
- System.arraycopy(elementData, r,
- elementData, w,
- size - r);
- w += size - r;
- }
- if (w != size) {
- for (int i = w; i < size; i++)
- elementData[i] = null;
- modCount += size - w;
- size = w;
- modified = true;
- }
- }
- return modified;
+ boolean batchRemove(Collection> c, boolean complement,
+ final int from, final int end) {
+ Objects.requireNonNull(c);
+ final Object[] es = elementData;
+ final boolean modified;
+ int r;
+ // Optimize for initial run of survivors
+ for (r = from; r < end && c.contains(es[r]) == complement; r++)
+ ;
+ if (modified = (r < end)) {
+ int w = r++;
+ try {
+ for (Object e; r < end; r++)
+ if (c.contains(e = es[r]) == complement)
+ es[w++] = e;
+ } catch (Throwable ex) {
+ // Preserve behavioral compatibility with AbstractCollection,
+ // even if c.contains() throws.
+ System.arraycopy(es, r, es, w, end - r);
+ w += end - r;
+ throw ex;
+ } finally {
+ modCount += end - w;
+ shiftTailOverGap(es, w, end);
+ }
+ }
+ // checkInvariants();
+ return modified;
}
/**
- * Save the state of the ArrayList instance to a stream (that
- * is, serialize it).
+ * Saves the state of the {@code ArrayList} instance to a stream
+ * (that is, serializes it).
*
- * @serialData The length of the array backing the ArrayList
+ * @param s the stream
+ * @throws java.io.IOException if an I/O error occurs
+ * @serialData The length of the array backing the {@code ArrayList}
* instance is emitted (int), followed by all of its elements
- * (each an Object) in the proper order.
+ * (each an {@code Object}) in the proper order.
*/
private void writeObject(java.io.ObjectOutputStream s)
- throws java.io.IOException{
- // Write out element count, and any hidden stuff
- int expectedModCount = modCount;
- s.defaultWriteObject();
+ throws java.io.IOException {
+ // Write out element count, and any hidden stuff
+ int expectedModCount = modCount;
+ s.defaultWriteObject();
- // Write out array length
- s.writeInt(elementData.length);
+ // Write out size as capacity for behavioural compatibility with clone()
+ s.writeInt(size);
- // Write out all elements in the proper order.
- for (int i=0; iArrayList instance from a stream (that is,
- * deserialize it).
+ * Reconstitutes the {@code ArrayList} instance from a stream (that is,
+ * deserializes it).
+ * @param s the stream
+ * @throws ClassNotFoundException if the class of a serialized object
+ * could not be found
+ * @throws java.io.IOException if an I/O error occurs
*/
private void readObject(java.io.ObjectInputStream s)
throws java.io.IOException, ClassNotFoundException {
- // Read in size, and any hidden stuff
- s.defaultReadObject();
- // Read in array length and allocate array
- int arrayLength = s.readInt();
- Object[] a = elementData = new Object[arrayLength];
-
- // Read in all elements in the proper order.
- for (int i=0; i 0) {
+ // like clone(), allocate array based upon size not capacity
+ Object[] elements = new Object[size];
+
+ // Read in all elements in the proper order.
+ for (int i = 0; i < size; i++) {
+ elements[i] = s.readObject();
+ }
+
+ elementData = elements;
+ } else if (size == 0) {
+ elementData = EMPTY_ELEMENTDATA;
+ } else {
+ throw new java.io.InvalidObjectException("Invalid size: " + size);
+ }
}
/**
@@ -710,9 +850,8 @@ public class ArrayList extends Abstra
* @throws IndexOutOfBoundsException {@inheritDoc}
*/
public ListIterator listIterator(int index) {
- if (index < 0 || index > size)
- throw new IndexOutOfBoundsException("Index: "+index);
- return new ListItr(index);
+ rangeCheckForAdd(index);
+ return new ListItr(index);
}
/**
@@ -724,7 +863,7 @@ public class ArrayList extends Abstra
* @see #listIterator(int)
*/
public ListIterator listIterator() {
- return new ListItr(0);
+ return new ListItr(0);
}
/**
@@ -735,114 +874,135 @@ public class ArrayList extends Abstra
* @return an iterator over the elements in this list in proper sequence
*/
public Iterator iterator() {
- return new Itr();
+ return new Itr();
}
/**
* An optimized version of AbstractList.Itr
*/
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;
+ int cursor; // index of next element to return
+ int lastRet = -1; // index of last element returned; -1 if no such
+ int expectedModCount = modCount;
+
+ // prevent creating a synthetic constructor
+ Itr() {}
- public boolean hasNext() {
+ public boolean hasNext() {
return cursor != size;
- }
+ }
- @SuppressWarnings("unchecked")
- public E next() {
+ @SuppressWarnings("unchecked")
+ public E next() {
checkForComodification();
- int i = cursor;
- if (i >= size)
- throw new NoSuchElementException();
- Object[] elementData = ArrayList.this.elementData;
- if (i >= elementData.length)
- throw new ConcurrentModificationException();
- cursor = i + 1;
- return (E) elementData[lastRet = i];
- }
-
- public void remove() {
- if (lastRet < 0)
- throw new IllegalStateException();
+ int i = cursor;
+ if (i >= size)
+ throw new NoSuchElementException();
+ Object[] elementData = ArrayList.this.elementData;
+ if (i >= elementData.length)
+ throw new ConcurrentModificationException();
+ cursor = i + 1;
+ return (E) elementData[lastRet = i];
+ }
+
+ public void remove() {
+ if (lastRet < 0)
+ throw new IllegalStateException();
checkForComodification();
- try {
- ArrayList.this.remove(lastRet);
- cursor = lastRet;
- lastRet = -1;
- expectedModCount = modCount;
- } catch (IndexOutOfBoundsException ex) {
- throw new ConcurrentModificationException();
- }
- }
-
- final void checkForComodification() {
- if (modCount != expectedModCount)
- throw new ConcurrentModificationException();
- }
+ try {
+ ArrayList.this.remove(lastRet);
+ cursor = lastRet;
+ lastRet = -1;
+ expectedModCount = modCount;
+ } catch (IndexOutOfBoundsException ex) {
+ throw new ConcurrentModificationException();
+ }
+ }
+
+ @Override
+ public void forEachRemaining(Consumer super E> action) {
+ Objects.requireNonNull(action);
+ final int size = ArrayList.this.size;
+ int i = cursor;
+ if (i < size) {
+ final Object[] es = elementData;
+ if (i >= es.length)
+ throw new ConcurrentModificationException();
+ for (; i < size && modCount == expectedModCount; i++)
+ action.accept(elementAt(es, i));
+ // update once at end to reduce heap write traffic
+ cursor = i;
+ lastRet = i - 1;
+ checkForComodification();
+ }
+ }
+
+ final void checkForComodification() {
+ if (modCount != expectedModCount)
+ throw new ConcurrentModificationException();
+ }
}
/**
* An optimized version of AbstractList.ListItr
*/
private class ListItr extends Itr implements ListIterator {
- ListItr(int index) {
- super();
- cursor = index;
- }
-
- public boolean hasPrevious() {
- return cursor != 0;
- }
-
- public int nextIndex() {
- return cursor;
- }
-
- public int previousIndex() {
- return cursor - 1;
- }
+ ListItr(int index) {
+ super();
+ cursor = index;
+ }
+
+ public boolean hasPrevious() {
+ return cursor != 0;
+ }
+
+ public int nextIndex() {
+ return cursor;
+ }
- @SuppressWarnings("unchecked")
+ public int previousIndex() {
+ return cursor - 1;
+ }
+
+ @SuppressWarnings("unchecked")
public E previous() {
- checkForComodification();
- int i = cursor - 1;
- if (i < 0)
- throw new NoSuchElementException();
- Object[] elementData = ArrayList.this.elementData;
- if (i >= elementData.length)
- throw new ConcurrentModificationException();
- cursor = i;
- return (E) elementData[lastRet = i];
+ checkForComodification();
+ int i = cursor - 1;
+ if (i < 0)
+ throw new NoSuchElementException();
+ Object[] elementData = ArrayList.this.elementData;
+ if (i >= elementData.length)
+ throw new ConcurrentModificationException();
+ cursor = i;
+ return (E) elementData[lastRet = i];
}
- public void set(E e) {
- if (lastRet < 0)
- throw new IllegalStateException();
+ public void set(E e) {
+ if (lastRet < 0)
+ throw new IllegalStateException();
checkForComodification();
- try {
- ArrayList.this.set(lastRet, e);
- } catch (IndexOutOfBoundsException ex) {
- throw new ConcurrentModificationException();
- }
- }
+ try {
+ ArrayList.this.set(lastRet, e);
+ } catch (IndexOutOfBoundsException ex) {
+ throw new ConcurrentModificationException();
+ }
+ }
- public void add(E e) {
+ public void add(E e) {
checkForComodification();
- try {
- int i = cursor;
- ArrayList.this.add(i, e);
- cursor = i + 1;
- lastRet = -1;
- expectedModCount = modCount;
- } catch (IndexOutOfBoundsException ex) {
- throw new ConcurrentModificationException();
- }
- }
+ try {
+ int i = cursor;
+ ArrayList.this.add(i, e);
+ cursor = i + 1;
+ lastRet = -1;
+ expectedModCount = modCount;
+ } catch (IndexOutOfBoundsException ex) {
+ throw new ConcurrentModificationException();
+ }
+ }
}
/**
@@ -875,221 +1035,565 @@ public class ArrayList extends Abstra
* @throws IllegalArgumentException {@inheritDoc}
*/
public List subList(int fromIndex, int toIndex) {
- subListRangeCheck(fromIndex, toIndex, size);
- return new SubList(this, 0, fromIndex, toIndex);
+ subListRangeCheck(fromIndex, toIndex, size);
+ return new SubList<>(this, fromIndex, toIndex);
+ }
+
+ private static class SubList extends AbstractList implements RandomAccess {
+ private final ArrayList root;
+ private final SubList parent;
+ private final int offset;
+ private int size;
+
+ /**
+ * Constructs a sublist of an arbitrary ArrayList.
+ */
+ public SubList(ArrayList root, int fromIndex, int toIndex) {
+ this.root = root;
+ this.parent = null;
+ this.offset = fromIndex;
+ this.size = toIndex - fromIndex;
+ this.modCount = root.modCount;
+ }
+
+ /**
+ * Constructs a sublist of another SubList.
+ */
+ private SubList(SubList parent, int fromIndex, int toIndex) {
+ this.root = parent.root;
+ this.parent = parent;
+ this.offset = parent.offset + fromIndex;
+ this.size = toIndex - fromIndex;
+ this.modCount = root.modCount;
+ }
+
+ public E set(int index, E element) {
+ Objects.checkIndex(index, size);
+ checkForComodification();
+ E oldValue = root.elementData(offset + index);
+ root.elementData[offset + index] = element;
+ return oldValue;
+ }
+
+ public E get(int index) {
+ Objects.checkIndex(index, size);
+ checkForComodification();
+ return root.elementData(offset + index);
+ }
+
+ public int size() {
+ checkForComodification();
+ return size;
+ }
+
+ public void add(int index, E element) {
+ rangeCheckForAdd(index);
+ checkForComodification();
+ root.add(offset + index, element);
+ updateSizeAndModCount(1);
+ }
+
+ public E remove(int index) {
+ Objects.checkIndex(index, size);
+ checkForComodification();
+ E result = root.remove(offset + index);
+ updateSizeAndModCount(-1);
+ return result;
+ }
+
+ protected void removeRange(int fromIndex, int toIndex) {
+ checkForComodification();
+ root.removeRange(offset + fromIndex, offset + toIndex);
+ updateSizeAndModCount(fromIndex - toIndex);
+ }
+
+ public boolean addAll(Collection extends E> c) {
+ return addAll(this.size, c);
+ }
+
+ public boolean addAll(int index, Collection extends E> c) {
+ rangeCheckForAdd(index);
+ int cSize = c.size();
+ if (cSize==0)
+ return false;
+ checkForComodification();
+ root.addAll(offset + index, c);
+ updateSizeAndModCount(cSize);
+ return true;
+ }
+
+ public boolean removeAll(Collection> c) {
+ return batchRemove(c, false);
+ }
+
+ public boolean retainAll(Collection> c) {
+ return batchRemove(c, true);
+ }
+
+ private boolean batchRemove(Collection> c, boolean complement) {
+ checkForComodification();
+ int oldSize = root.size;
+ boolean modified =
+ root.batchRemove(c, complement, offset, offset + size);
+ if (modified)
+ updateSizeAndModCount(root.size - oldSize);
+ return modified;
+ }
+
+ public boolean removeIf(Predicate super E> filter) {
+ checkForComodification();
+ int oldSize = root.size;
+ boolean modified = root.removeIf(filter, offset, offset + size);
+ if (modified)
+ updateSizeAndModCount(root.size - oldSize);
+ return modified;
+ }
+
+ public Iterator iterator() {
+ return listIterator();
+ }
+
+ public ListIterator listIterator(int index) {
+ checkForComodification();
+ rangeCheckForAdd(index);
+
+ return new ListIterator() {
+ int cursor = index;
+ int lastRet = -1;
+ int expectedModCount = root.modCount;
+
+ public boolean hasNext() {
+ return cursor != SubList.this.size;
+ }
+
+ @SuppressWarnings("unchecked")
+ public E next() {
+ checkForComodification();
+ int i = cursor;
+ if (i >= SubList.this.size)
+ throw new NoSuchElementException();
+ Object[] elementData = root.elementData;
+ if (offset + i >= elementData.length)
+ throw new ConcurrentModificationException();
+ cursor = i + 1;
+ return (E) elementData[offset + (lastRet = i)];
+ }
+
+ public boolean hasPrevious() {
+ return cursor != 0;
+ }
+
+ @SuppressWarnings("unchecked")
+ public E previous() {
+ checkForComodification();
+ int i = cursor - 1;
+ if (i < 0)
+ throw new NoSuchElementException();
+ Object[] elementData = root.elementData;
+ if (offset + i >= elementData.length)
+ throw new ConcurrentModificationException();
+ cursor = i;
+ return (E) elementData[offset + (lastRet = i)];
+ }
+
+ public void forEachRemaining(Consumer super E> action) {
+ Objects.requireNonNull(action);
+ final int size = SubList.this.size;
+ int i = cursor;
+ if (i < size) {
+ final Object[] es = root.elementData;
+ if (offset + i >= es.length)
+ throw new ConcurrentModificationException();
+ for (; i < size && modCount == expectedModCount; i++)
+ action.accept(elementAt(es, offset + i));
+ // update once at end to reduce heap write traffic
+ cursor = i;
+ lastRet = i - 1;
+ checkForComodification();
+ }
+ }
+
+ public int nextIndex() {
+ return cursor;
+ }
+
+ public int previousIndex() {
+ return cursor - 1;
+ }
+
+ public void remove() {
+ if (lastRet < 0)
+ throw new IllegalStateException();
+ checkForComodification();
+
+ try {
+ SubList.this.remove(lastRet);
+ cursor = lastRet;
+ lastRet = -1;
+ expectedModCount = root.modCount;
+ } catch (IndexOutOfBoundsException ex) {
+ throw new ConcurrentModificationException();
+ }
+ }
+
+ public void set(E e) {
+ if (lastRet < 0)
+ throw new IllegalStateException();
+ checkForComodification();
+
+ try {
+ root.set(offset + lastRet, e);
+ } catch (IndexOutOfBoundsException ex) {
+ throw new ConcurrentModificationException();
+ }
+ }
+
+ public void add(E e) {
+ checkForComodification();
+
+ try {
+ int i = cursor;
+ SubList.this.add(i, e);
+ cursor = i + 1;
+ lastRet = -1;
+ expectedModCount = root.modCount;
+ } catch (IndexOutOfBoundsException ex) {
+ throw new ConcurrentModificationException();
+ }
+ }
+
+ final void checkForComodification() {
+ if (root.modCount != expectedModCount)
+ throw new ConcurrentModificationException();
+ }
+ };
+ }
+
+ public List subList(int fromIndex, int toIndex) {
+ subListRangeCheck(fromIndex, toIndex, size);
+ return new SubList<>(this, fromIndex, toIndex);
+ }
+
+ private void rangeCheckForAdd(int index) {
+ if (index < 0 || index > this.size)
+ throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
+ }
+
+ private String outOfBoundsMsg(int index) {
+ return "Index: "+index+", Size: "+this.size;
+ }
+
+ private void checkForComodification() {
+ if (root.modCount != modCount)
+ throw new ConcurrentModificationException();
+ }
+
+ private void updateSizeAndModCount(int sizeChange) {
+ SubList slist = this;
+ do {
+ slist.size += sizeChange;
+ slist.modCount = root.modCount;
+ slist = slist.parent;
+ } while (slist != null);
+ }
+
+ public Spliterator spliterator() {
+ checkForComodification();
+
+ // ArrayListSpliterator not used here due to late-binding
+ return new Spliterator() {
+ private int index = offset; // current index, modified on advance/split
+ private int fence = -1; // -1 until used; then one past last index
+ private int expectedModCount; // initialized when fence set
+
+ private int getFence() { // initialize fence to size on first use
+ int hi; // (a specialized variant appears in method forEach)
+ if ((hi = fence) < 0) {
+ expectedModCount = modCount;
+ hi = fence = offset + size;
+ }
+ return hi;
+ }
+
+ public ArrayList.ArrayListSpliterator trySplit() {
+ int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
+ // ArrayListSpliterator can be used here as the source is already bound
+ return (lo >= mid) ? null : // divide range in half unless too small
+ root.new ArrayListSpliterator(lo, index = mid, expectedModCount);
+ }
+
+ public boolean tryAdvance(Consumer super E> action) {
+ Objects.requireNonNull(action);
+ int hi = getFence(), i = index;
+ if (i < hi) {
+ index = i + 1;
+ @SuppressWarnings("unchecked") E e = (E)root.elementData[i];
+ action.accept(e);
+ if (root.modCount != expectedModCount)
+ throw new ConcurrentModificationException();
+ return true;
+ }
+ return false;
+ }
+
+ public void forEachRemaining(Consumer super E> action) {
+ Objects.requireNonNull(action);
+ int i, hi, mc; // hoist accesses and checks from loop
+ ArrayList lst = root;
+ Object[] a;
+ if ((a = lst.elementData) != null) {
+ if ((hi = fence) < 0) {
+ mc = modCount;
+ hi = offset + size;
+ }
+ else
+ mc = expectedModCount;
+ if ((i = index) >= 0 && (index = hi) <= a.length) {
+ for (; i < hi; ++i) {
+ @SuppressWarnings("unchecked") E e = (E) a[i];
+ action.accept(e);
+ }
+ if (lst.modCount == mc)
+ return;
+ }
+ }
+ throw new ConcurrentModificationException();
+ }
+
+ public long estimateSize() {
+ return getFence() - index;
+ }
+
+ public int characteristics() {
+ return Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED;
+ }
+ };
+ }
+ }
+
+ @Override
+ public void forEach(Consumer super E> action) {
+ Objects.requireNonNull(action);
+ final int expectedModCount = modCount;
+ final Object[] es = elementData;
+ final int size = this.size;
+ for (int i = 0; modCount == expectedModCount && i < size; i++)
+ action.accept(elementAt(es, i));
+ if (modCount != expectedModCount)
+ throw new ConcurrentModificationException();
+ }
+
+ /**
+ * Creates a late-binding
+ * and fail-fast {@link Spliterator} over the elements in this
+ * list.
+ *
+ * The {@code Spliterator} reports {@link Spliterator#SIZED},
+ * {@link Spliterator#SUBSIZED}, and {@link Spliterator#ORDERED}.
+ * Overriding implementations should document the reporting of additional
+ * characteristic values.
+ *
+ * @return a {@code Spliterator} over the elements in this list
+ * @since 1.8
+ */
+ @Override
+ public Spliterator spliterator() {
+ return new ArrayListSpliterator(0, -1, 0);
+ }
+
+ /** Index-based split-by-two, lazily initialized Spliterator */
+ final class ArrayListSpliterator implements Spliterator {
+
+ /*
+ * If ArrayLists were immutable, or structurally immutable (no
+ * adds, removes, etc), we could implement their spliterators
+ * with Arrays.spliterator. Instead we detect as much
+ * interference during traversal as practical without
+ * sacrificing much performance. We rely primarily on
+ * modCounts. These are not guaranteed to detect concurrency
+ * violations, and are sometimes overly conservative about
+ * within-thread interference, but detect enough problems to
+ * be worthwhile in practice. To carry this out, we (1) lazily
+ * initialize fence and expectedModCount until the latest
+ * point that we need to commit to the state we are checking
+ * against; thus improving precision. (This doesn't apply to
+ * SubLists, that create spliterators with current non-lazy
+ * values). (2) We perform only a single
+ * ConcurrentModificationException check at the end of forEach
+ * (the most performance-sensitive method). When using forEach
+ * (as opposed to iterators), we can normally only detect
+ * interference after actions, not before. Further
+ * CME-triggering checks apply to all other possible
+ * violations of assumptions for example null or too-small
+ * elementData array given its size(), that could only have
+ * occurred due to interference. This allows the inner loop
+ * of forEach to run without any further checks, and
+ * simplifies lambda-resolution. While this does entail a
+ * number of checks, note that in the common case of
+ * list.stream().forEach(a), no checks or other computation
+ * occur anywhere other than inside forEach itself. The other
+ * less-often-used methods cannot take advantage of most of
+ * these streamlinings.
+ */
+
+ private int index; // current index, modified on advance/split
+ private int fence; // -1 until used; then one past last index
+ private int expectedModCount; // initialized when fence set
+
+ /** Create new spliterator covering the given range */
+ ArrayListSpliterator(int origin, int fence, int expectedModCount) {
+ this.index = origin;
+ this.fence = fence;
+ this.expectedModCount = expectedModCount;
+ }
+
+ private int getFence() { // initialize fence to size on first use
+ int hi; // (a specialized variant appears in method forEach)
+ if ((hi = fence) < 0) {
+ expectedModCount = modCount;
+ hi = fence = size;
+ }
+ return hi;
+ }
+
+ public ArrayListSpliterator trySplit() {
+ int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
+ return (lo >= mid) ? null : // divide range in half unless too small
+ new ArrayListSpliterator(lo, index = mid, expectedModCount);
+ }
+
+ public boolean tryAdvance(Consumer super E> action) {
+ if (action == null)
+ throw new NullPointerException();
+ int hi = getFence(), i = index;
+ if (i < hi) {
+ index = i + 1;
+ @SuppressWarnings("unchecked") E e = (E)elementData[i];
+ action.accept(e);
+ if (modCount != expectedModCount)
+ throw new ConcurrentModificationException();
+ return true;
+ }
+ return false;
+ }
+
+ public void forEachRemaining(Consumer super E> action) {
+ int i, hi, mc; // hoist accesses and checks from loop
+ Object[] a;
+ if (action == null)
+ throw new NullPointerException();
+ if ((a = elementData) != null) {
+ if ((hi = fence) < 0) {
+ mc = modCount;
+ hi = size;
+ }
+ else
+ mc = expectedModCount;
+ if ((i = index) >= 0 && (index = hi) <= a.length) {
+ for (; i < hi; ++i) {
+ @SuppressWarnings("unchecked") E e = (E) a[i];
+ action.accept(e);
+ }
+ if (modCount == mc)
+ return;
+ }
+ }
+ throw new ConcurrentModificationException();
+ }
+
+ public long estimateSize() {
+ return getFence() - index;
+ }
+
+ public int characteristics() {
+ return Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED;
+ }
+ }
+
+ // A tiny bit set implementation
+
+ private static long[] nBits(int n) {
+ return new long[((n - 1) >> 6) + 1];
+ }
+ private static void setBit(long[] bits, int i) {
+ bits[i >> 6] |= 1L << i;
+ }
+ private static boolean isClear(long[] bits, int i) {
+ return (bits[i >> 6] & (1L << i)) == 0;
+ }
+
+ @Override
+ public boolean removeIf(Predicate super E> filter) {
+ return removeIf(filter, 0, size);
+ }
+
+ /**
+ * Removes all elements satisfying the given predicate, from index
+ * i (inclusive) to index end (exclusive).
+ */
+ boolean removeIf(Predicate super E> filter, int i, final int end) {
+ Objects.requireNonNull(filter);
+ int expectedModCount = modCount;
+ final Object[] es = elementData;
+ // Optimize for initial run of survivors
+ for (; i < end && !filter.test(elementAt(es, i)); i++)
+ ;
+ // Tolerate predicates that reentrantly access the collection for
+ // read (but writers still get CME), so traverse once to find
+ // elements to delete, a second pass to physically expunge.
+ if (i < end) {
+ final int beg = i;
+ final long[] deathRow = nBits(end - beg);
+ deathRow[0] = 1L; // set bit 0
+ for (i = beg + 1; i < end; i++)
+ if (filter.test(elementAt(es, i)))
+ setBit(deathRow, i - beg);
+ if (modCount != expectedModCount)
+ throw new ConcurrentModificationException();
+ expectedModCount++;
+ modCount++;
+ int w = beg;
+ for (i = beg; i < end; i++)
+ if (isClear(deathRow, i - beg))
+ es[w++] = es[i];
+ shiftTailOverGap(es, w, end);
+ // checkInvariants();
+ return true;
+ } else {
+ if (modCount != expectedModCount)
+ throw new ConcurrentModificationException();
+ // checkInvariants();
+ return false;
+ }
+ }
+
+ @Override
+ public void replaceAll(UnaryOperator operator) {
+ Objects.requireNonNull(operator);
+ final int expectedModCount = modCount;
+ final Object[] es = elementData;
+ final int size = this.size;
+ for (int i = 0; modCount == expectedModCount && i < size; i++)
+ es[i] = operator.apply(elementAt(es, i));
+ if (modCount != expectedModCount)
+ throw new ConcurrentModificationException();
+ modCount++;
+ // checkInvariants();
+ }
+
+ @Override
+ @SuppressWarnings("unchecked")
+ public void sort(Comparator super E> c) {
+ final int expectedModCount = modCount;
+ Arrays.sort((E[]) elementData, 0, size, c);
+ if (modCount != expectedModCount)
+ throw new ConcurrentModificationException();
+ modCount++;
+ // checkInvariants();
}
- static void subListRangeCheck(int fromIndex, int toIndex, int size) {
- if (fromIndex < 0)
- throw new IndexOutOfBoundsException("fromIndex = " + fromIndex);
- if (toIndex > size)
- throw new IndexOutOfBoundsException("toIndex = " + toIndex);
- if (fromIndex > toIndex)
- throw new IllegalArgumentException("fromIndex(" + fromIndex +
- ") > toIndex(" + toIndex + ")");
- }
-
- private class SubList extends AbstractList implements RandomAccess {
- private final AbstractList parent;
- private final int parentOffset;
- private final int offset;
- private int size;
-
- SubList(AbstractList parent,
- int offset, int fromIndex, int toIndex) {
- this.parent = parent;
- this.parentOffset = fromIndex;
- this.offset = offset + fromIndex;
- this.size = toIndex - fromIndex;
- this.modCount = ArrayList.this.modCount;
- }
-
- public E set(int index, E e) {
- rangeCheck(index);
- checkForComodification();
- E oldValue = ArrayList.this.elementData(offset + index);
- ArrayList.this.elementData[offset + index] = e;
- return oldValue;
- }
-
- public E get(int index) {
- rangeCheck(index);
- checkForComodification();
- return ArrayList.this.elementData(offset + index);
- }
-
- public int size() {
- checkForComodification();
- return this.size;
- }
-
- public void add(int index, E e) {
- rangeCheckForAdd(index);
- checkForComodification();
- parent.add(parentOffset + index, e);
- this.modCount = parent.modCount;
- this.size++;
- }
-
- public E remove(int index) {
- rangeCheck(index);
- checkForComodification();
- E result = parent.remove(parentOffset + index);
- this.modCount = parent.modCount;
- this.size--;
- return result;
- }
-
- protected void removeRange(int fromIndex, int toIndex) {
- checkForComodification();
- parent.removeRange(parentOffset + fromIndex,
- parentOffset + toIndex);
- this.modCount = parent.modCount;
- this.size -= toIndex - fromIndex;
- }
-
- public boolean addAll(Collection extends E> c) {
- return addAll(this.size, c);
- }
-
- public boolean addAll(int index, Collection extends E> c) {
- rangeCheckForAdd(index);
- int cSize = c.size();
- if (cSize==0)
- return false;
-
- checkForComodification();
- parent.addAll(parentOffset + index, c);
- this.modCount = parent.modCount;
- this.size += cSize;
- return true;
- }
-
- public Iterator iterator() {
- return listIterator();
- }
-
- public ListIterator listIterator(final int index) {
- checkForComodification();
- rangeCheckForAdd(index);
-
- return new ListIterator() {
- int cursor = index;
- int lastRet = -1;
- int expectedModCount = ArrayList.this.modCount;
-
- public boolean hasNext() {
- return cursor != SubList.this.size;
- }
-
- @SuppressWarnings("unchecked")
- public E next() {
- checkForComodification();
- int i = cursor;
- if (i >= SubList.this.size)
- throw new NoSuchElementException();
- Object[] elementData = ArrayList.this.elementData;
- if (offset + i >= elementData.length)
- throw new ConcurrentModificationException();
- cursor = i + 1;
- return (E) elementData[offset + (lastRet = i)];
- }
-
- public boolean hasPrevious() {
- return cursor != 0;
- }
-
- @SuppressWarnings("unchecked")
- public E previous() {
- checkForComodification();
- int i = cursor - 1;
- if (i < 0)
- throw new NoSuchElementException();
- Object[] elementData = ArrayList.this.elementData;
- if (offset + i >= elementData.length)
- throw new ConcurrentModificationException();
- cursor = i;
- return (E) elementData[offset + (lastRet = i)];
- }
-
- public int nextIndex() {
- return cursor;
- }
-
- public int previousIndex() {
- return cursor - 1;
- }
-
- public void remove() {
- if (lastRet < 0)
- throw new IllegalStateException();
- checkForComodification();
-
- try {
- SubList.this.remove(lastRet);
- cursor = lastRet;
- lastRet = -1;
- expectedModCount = ArrayList.this.modCount;
- } catch (IndexOutOfBoundsException ex) {
- throw new ConcurrentModificationException();
- }
- }
-
- public void set(E e) {
- if (lastRet < 0)
- throw new IllegalStateException();
- checkForComodification();
-
- try {
- ArrayList.this.set(offset + lastRet, e);
- } catch (IndexOutOfBoundsException ex) {
- throw new ConcurrentModificationException();
- }
- }
-
- public void add(E e) {
- checkForComodification();
-
- try {
- int i = cursor;
- SubList.this.add(i, e);
- cursor = i + 1;
- lastRet = -1;
- expectedModCount = ArrayList.this.modCount;
- } catch (IndexOutOfBoundsException ex) {
- throw new ConcurrentModificationException();
- }
- }
-
- final void checkForComodification() {
- if (expectedModCount != ArrayList.this.modCount)
- throw new ConcurrentModificationException();
- }
- };
- }
-
- public List subList(int fromIndex, int toIndex) {
- subListRangeCheck(fromIndex, toIndex, size);
- return new SubList(this, offset, fromIndex, toIndex);
- }
-
- private void rangeCheck(int index) {
- if (index < 0 || index >= this.size)
- throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
- }
-
- private void rangeCheckForAdd(int index) {
- if (index < 0 || index > this.size)
- throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
- }
-
- private String outOfBoundsMsg(int index) {
- return "Index: "+index+", Size: "+this.size;
- }
-
- private void checkForComodification() {
- if (ArrayList.this.modCount != this.modCount)
- throw new ConcurrentModificationException();
- }
+ void checkInvariants() {
+ // assert size >= 0;
+ // assert size == elementData.length || elementData[size] == null;
}
}