1 |
dl |
1.2 |
/* |
2 |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
3 |
dl |
1.17 |
* Expert Group. Adapted and released, under explicit permission, |
4 |
dl |
1.15 |
* from JDK ArrayList.java which carries the following copyright: |
5 |
dl |
1.3 |
* |
6 |
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* Copyright 1997 by Sun Microsystems, Inc., |
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* 901 San Antonio Road, Palo Alto, California, 94303, U.S.A. |
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* All rights reserved. |
9 |
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* |
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* This software is the confidential and proprietary information |
11 |
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* of Sun Microsystems, Inc. ("Confidential Information"). You |
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* shall not disclose such Confidential Information and shall use |
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* it only in accordance with the terms of the license agreement |
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* you entered into with Sun. |
15 |
dl |
1.2 |
*/ |
16 |
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|
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tim |
1.1 |
package java.util.concurrent; |
18 |
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import java.util.*; |
19 |
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20 |
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/** |
21 |
dl |
1.28 |
* A thread-safe variant of {@link java.util.ArrayList} in which all mutative |
22 |
jsr166 |
1.35 |
* operations (<tt>add</tt>, <tt>set</tt>, and so on) are implemented by |
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* making a fresh copy of the underlying array. |
24 |
tim |
1.1 |
* |
25 |
dl |
1.26 |
* <p> This is ordinarily too costly, but may be <em>more</em> efficient |
26 |
dl |
1.12 |
* than alternatives when traversal operations vastly outnumber |
27 |
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* mutations, and is useful when you cannot or don't want to |
28 |
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* synchronize traversals, yet need to preclude interference among |
29 |
dl |
1.15 |
* concurrent threads. The "snapshot" style iterator method uses a |
30 |
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* reference to the state of the array at the point that the iterator |
31 |
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* was created. This array never changes during the lifetime of the |
32 |
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* iterator, so interference is impossible and the iterator is |
33 |
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* guaranteed not to throw <tt>ConcurrentModificationException</tt>. |
34 |
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* The iterator will not reflect additions, removals, or changes to |
35 |
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* the list since the iterator was created. Element-changing |
36 |
jsr166 |
1.35 |
* operations on iterators themselves (<tt>remove</tt>, <tt>set</tt>, and |
37 |
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* <tt>add</tt>) are not supported. These methods throw |
38 |
dl |
1.15 |
* <tt>UnsupportedOperationException</tt>. |
39 |
dl |
1.24 |
* |
40 |
jsr166 |
1.35 |
* <p>All elements are permitted, including <tt>null</tt>. |
41 |
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* |
42 |
dl |
1.24 |
* <p>This class is a member of the |
43 |
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* <a href="{@docRoot}/../guide/collections/index.html"> |
44 |
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* Java Collections Framework</a>. |
45 |
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* |
46 |
dl |
1.6 |
* @since 1.5 |
47 |
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* @author Doug Lea |
48 |
dl |
1.19 |
* @param <E> the type of elements held in this collection |
49 |
dl |
1.6 |
*/ |
50 |
tim |
1.1 |
public class CopyOnWriteArrayList<E> |
51 |
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implements List<E>, RandomAccess, Cloneable, java.io.Serializable { |
52 |
dl |
1.11 |
private static final long serialVersionUID = 8673264195747942595L; |
53 |
tim |
1.1 |
|
54 |
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/** |
55 |
dl |
1.6 |
* The held array. Directly accessed only within synchronized |
56 |
jsr166 |
1.35 |
* methods. |
57 |
tim |
1.1 |
*/ |
58 |
dl |
1.12 |
private volatile transient E[] array; |
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tim |
1.1 |
|
60 |
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/** |
61 |
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* Accessor to the array intended to be called from |
62 |
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* within unsynchronized read-only methods |
63 |
jsr166 |
1.30 |
*/ |
64 |
dl |
1.12 |
private E[] array() { return array; } |
65 |
tim |
1.1 |
|
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/** |
67 |
dl |
1.15 |
* Creates an empty list. |
68 |
tim |
1.1 |
*/ |
69 |
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public CopyOnWriteArrayList() { |
70 |
dl |
1.12 |
array = (E[]) new Object[0]; |
71 |
tim |
1.1 |
} |
72 |
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73 |
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/** |
74 |
dl |
1.15 |
* Creates a list containing the elements of the specified |
75 |
jsr166 |
1.32 |
* collection, in the order they are returned by the collection's |
76 |
tim |
1.1 |
* iterator. |
77 |
jsr166 |
1.32 |
* |
78 |
dl |
1.6 |
* @param c the collection of initially held elements |
79 |
jsr166 |
1.35 |
* @throws NullPointerException if the specified collection is null |
80 |
tim |
1.1 |
*/ |
81 |
tim |
1.22 |
public CopyOnWriteArrayList(Collection<? extends E> c) { |
82 |
dl |
1.12 |
array = (E[]) new Object[c.size()]; |
83 |
tim |
1.22 |
Iterator<? extends E> i = c.iterator(); |
84 |
tim |
1.1 |
int size = 0; |
85 |
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while (i.hasNext()) |
86 |
dl |
1.12 |
array[size++] = i.next(); |
87 |
tim |
1.1 |
} |
88 |
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|
89 |
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/** |
90 |
jsr166 |
1.35 |
* Creates a list holding a copy of the given array. |
91 |
tim |
1.9 |
* |
92 |
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* @param toCopyIn the array (a copy of this array is used as the |
93 |
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* internal array) |
94 |
jsr166 |
1.30 |
*/ |
95 |
tim |
1.1 |
public CopyOnWriteArrayList(E[] toCopyIn) { |
96 |
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copyIn(toCopyIn, 0, toCopyIn.length); |
97 |
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} |
98 |
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99 |
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/** |
100 |
jsr166 |
1.30 |
* Replaces the held array with a copy of the <tt>n</tt> elements |
101 |
dl |
1.25 |
* of the provided array, starting at position <tt>first</tt>. To |
102 |
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* copy an entire array, call with arguments (array, 0, |
103 |
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* array.length). |
104 |
tim |
1.1 |
* @param toCopyIn the array. A copy of the indicated elements of |
105 |
dl |
1.25 |
* this array is used as the internal array. |
106 |
tim |
1.1 |
* @param first The index of first position of the array to |
107 |
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* start copying from. |
108 |
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* @param n the number of elements to copy. This will be the new size of |
109 |
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* the list. |
110 |
jsr166 |
1.30 |
*/ |
111 |
tim |
1.1 |
private synchronized void copyIn(E[] toCopyIn, int first, int n) { |
112 |
jsr166 |
1.35 |
array = (E[]) new Object[n]; |
113 |
dl |
1.12 |
System.arraycopy(toCopyIn, first, array, 0, n); |
114 |
tim |
1.1 |
} |
115 |
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116 |
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/** |
117 |
dl |
1.15 |
* Returns the number of elements in this list. |
118 |
tim |
1.1 |
* |
119 |
jsr166 |
1.35 |
* @return the number of elements in this list |
120 |
tim |
1.1 |
*/ |
121 |
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public int size() { |
122 |
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return array().length; |
123 |
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} |
124 |
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125 |
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/** |
126 |
jsr166 |
1.35 |
* Returns <tt>true</tt> if this list contains no elements. |
127 |
tim |
1.1 |
* |
128 |
jsr166 |
1.35 |
* @return <tt>true</tt> if this list contains no elements |
129 |
tim |
1.1 |
*/ |
130 |
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public boolean isEmpty() { |
131 |
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return size() == 0; |
132 |
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} |
133 |
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134 |
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/** |
135 |
dl |
1.15 |
* Returns <tt>true</tt> if this list contains the specified element. |
136 |
jsr166 |
1.35 |
* More formally, returns <tt>true</tt> if and only if this list contains |
137 |
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* at least one element <tt>e</tt> such that |
138 |
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* <tt>(o==null ? e==null : o.equals(e))</tt>. |
139 |
tim |
1.1 |
* |
140 |
jsr166 |
1.35 |
* @param o element whose presence in this list is to be tested |
141 |
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* @return <tt>true</tt> if this list contains the specified element |
142 |
tim |
1.1 |
*/ |
143 |
jsr166 |
1.35 |
public boolean contains(Object o) { |
144 |
tim |
1.1 |
E[] elementData = array(); |
145 |
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int len = elementData.length; |
146 |
jsr166 |
1.35 |
return indexOf(o, elementData, len) >= 0; |
147 |
tim |
1.1 |
} |
148 |
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|
149 |
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/** |
150 |
jsr166 |
1.35 |
* {@inheritDoc} |
151 |
tim |
1.1 |
*/ |
152 |
jsr166 |
1.35 |
public int indexOf(Object o) { |
153 |
tim |
1.1 |
E[] elementData = array(); |
154 |
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int len = elementData.length; |
155 |
jsr166 |
1.35 |
return indexOf(o, elementData, len); |
156 |
tim |
1.1 |
} |
157 |
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|
158 |
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/** |
159 |
jsr166 |
1.35 |
* static version allows repeated call without needing |
160 |
tim |
1.1 |
* to grab lock for array each time |
161 |
jsr166 |
1.30 |
*/ |
162 |
jsr166 |
1.35 |
private static int indexOf(Object o, Object[] elementData, int len) { |
163 |
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if (o == null) { |
164 |
tim |
1.1 |
for (int i = 0; i < len; i++) |
165 |
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if (elementData[i]==null) |
166 |
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return i; |
167 |
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} else { |
168 |
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for (int i = 0; i < len; i++) |
169 |
jsr166 |
1.35 |
if (o.equals(elementData[i])) |
170 |
tim |
1.1 |
return i; |
171 |
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} |
172 |
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return -1; |
173 |
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} |
174 |
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175 |
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/** |
176 |
jsr166 |
1.35 |
* Returns the index of the first occurrence of the specified element in |
177 |
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* this list, searching forwards from <tt>index</tt>, or returns -1 if |
178 |
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* the element is not found. |
179 |
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* More formally, returns the lowest index <tt>i</tt> such that |
180 |
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* <tt>(i >= index && (e==null ? get(i)==null : e.equals(get(i))))</tt>, |
181 |
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* or -1 if there is no such index. |
182 |
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* |
183 |
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* @param e element to search for |
184 |
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* @param index index to start searching from |
185 |
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* @return the index of the first occurrence of the element in |
186 |
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* this list at position <tt>index</tt> or later in the list; |
187 |
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* <tt>-1</tt> if the element is not found. |
188 |
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* @throws IndexOutOfBoundsException if the specified index is negative |
189 |
tim |
1.1 |
*/ |
190 |
jsr166 |
1.35 |
public int indexOf(E e, int index) { |
191 |
tim |
1.1 |
E[] elementData = array(); |
192 |
|
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int elementCount = elementData.length; |
193 |
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|
194 |
jsr166 |
1.35 |
if (e == null) { |
195 |
tim |
1.1 |
for (int i = index ; i < elementCount ; i++) |
196 |
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if (elementData[i]==null) |
197 |
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return i; |
198 |
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} else { |
199 |
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for (int i = index ; i < elementCount ; i++) |
200 |
jsr166 |
1.35 |
if (e.equals(elementData[i])) |
201 |
tim |
1.1 |
return i; |
202 |
|
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} |
203 |
|
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return -1; |
204 |
|
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} |
205 |
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|
206 |
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/** |
207 |
jsr166 |
1.35 |
* {@inheritDoc} |
208 |
tim |
1.1 |
*/ |
209 |
jsr166 |
1.35 |
public int lastIndexOf(Object o) { |
210 |
tim |
1.1 |
E[] elementData = array(); |
211 |
|
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int len = elementData.length; |
212 |
jsr166 |
1.35 |
return lastIndexOf(o, elementData, len); |
213 |
tim |
1.1 |
} |
214 |
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|
215 |
jsr166 |
1.35 |
private static int lastIndexOf(Object o, Object[] elementData, int len) { |
216 |
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if (o == null) { |
217 |
tim |
1.1 |
for (int i = len-1; i >= 0; i--) |
218 |
|
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if (elementData[i]==null) |
219 |
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return i; |
220 |
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} else { |
221 |
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for (int i = len-1; i >= 0; i--) |
222 |
jsr166 |
1.35 |
if (o.equals(elementData[i])) |
223 |
tim |
1.1 |
return i; |
224 |
|
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} |
225 |
|
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return -1; |
226 |
|
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} |
227 |
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|
228 |
|
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/** |
229 |
jsr166 |
1.35 |
* Returns the index of the last occurrence of the specified element in |
230 |
|
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* this list, searching backwards from <tt>index</tt>, or returns -1 if |
231 |
|
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* the element is not found. |
232 |
|
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* More formally, returns the highest index <tt>i</tt> such that |
233 |
|
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* <tt>(i <= index && (e==null ? get(i)==null : e.equals(get(i))))</tt>, |
234 |
|
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* or -1 if there is no such index. |
235 |
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* |
236 |
|
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* @param e element to search for |
237 |
|
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* @param index index to start searching backwards from |
238 |
|
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* @return the index of the last occurrence of the element at position |
239 |
|
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* less than or equal to <tt>index</tt> in this list; |
240 |
|
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* -1 if the element is not found. |
241 |
|
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* @throws IndexOutOfBoundsException if the specified index is greater |
242 |
|
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* than or equal to the current size of this list |
243 |
tim |
1.1 |
*/ |
244 |
jsr166 |
1.35 |
public int lastIndexOf(E e, int index) { |
245 |
tim |
1.1 |
// needed in order to compile on 1.2b3 |
246 |
|
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E[] elementData = array(); |
247 |
jsr166 |
1.35 |
if (e == null) { |
248 |
tim |
1.1 |
for (int i = index; i >= 0; i--) |
249 |
|
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if (elementData[i]==null) |
250 |
|
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return i; |
251 |
|
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} else { |
252 |
|
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for (int i = index; i >= 0; i--) |
253 |
jsr166 |
1.35 |
if (e.equals(elementData[i])) |
254 |
tim |
1.1 |
return i; |
255 |
|
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} |
256 |
|
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return -1; |
257 |
|
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} |
258 |
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|
259 |
|
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/** |
260 |
|
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* Returns a shallow copy of this list. (The elements themselves |
261 |
|
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* are not copied.) |
262 |
|
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* |
263 |
jsr166 |
1.35 |
* @return a clone of this list |
264 |
tim |
1.1 |
*/ |
265 |
|
|
public Object clone() { |
266 |
|
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try { |
267 |
|
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E[] elementData = array(); |
268 |
tim |
1.8 |
CopyOnWriteArrayList<E> v = (CopyOnWriteArrayList<E>)super.clone(); |
269 |
dl |
1.12 |
v.array = (E[]) new Object[elementData.length]; |
270 |
|
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System.arraycopy(elementData, 0, v.array, 0, elementData.length); |
271 |
tim |
1.1 |
return v; |
272 |
|
|
} catch (CloneNotSupportedException e) { |
273 |
|
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// this shouldn't happen, since we are Cloneable |
274 |
|
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throw new InternalError(); |
275 |
|
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} |
276 |
|
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} |
277 |
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|
278 |
|
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/** |
279 |
|
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* Returns an array containing all of the elements in this list |
280 |
jsr166 |
1.35 |
* in proper sequence (from first to last element). |
281 |
|
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* |
282 |
|
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* <p>The returned array will be "safe" in that no references to it are |
283 |
|
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* maintained by this list. (In other words, this method must allocate |
284 |
|
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* a new array). The caller is thus free to modify the returned array. |
285 |
jsr166 |
1.36 |
* |
286 |
jsr166 |
1.35 |
* <p>This method acts as bridge between array-based and collection-based |
287 |
|
|
* APIs. |
288 |
|
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* |
289 |
|
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* @return an array containing all the elements in this list |
290 |
tim |
1.1 |
*/ |
291 |
|
|
public Object[] toArray() { |
292 |
|
|
Object[] elementData = array(); |
293 |
|
|
Object[] result = new Object[elementData.length]; |
294 |
|
|
System.arraycopy(elementData, 0, result, 0, elementData.length); |
295 |
|
|
return result; |
296 |
|
|
} |
297 |
|
|
|
298 |
|
|
/** |
299 |
jsr166 |
1.35 |
* Returns an array containing all of the elements in this list in |
300 |
|
|
* proper sequence (from first to last element); the runtime type of |
301 |
|
|
* the returned array is that of the specified array. If the list fits |
302 |
|
|
* in the specified array, it is returned therein. Otherwise, a new |
303 |
|
|
* array is allocated with the runtime type of the specified array and |
304 |
|
|
* the size of this list. |
305 |
jsr166 |
1.32 |
* |
306 |
|
|
* <p>If this list fits in the specified array with room to spare |
307 |
jsr166 |
1.35 |
* (i.e., the array has more elements than this list), the element in |
308 |
|
|
* the array immediately following the end of the list is set to |
309 |
|
|
* <tt>null</tt>. (This is useful in determining the length of this |
310 |
|
|
* list <i>only</i> if the caller knows that this list does not contain |
311 |
|
|
* any null elements.) |
312 |
|
|
* |
313 |
|
|
* <p>Like the {@link #toArray()} method, this method acts as bridge between |
314 |
|
|
* array-based and collection-based APIs. Further, this method allows |
315 |
|
|
* precise control over the runtime type of the output array, and may, |
316 |
|
|
* under certain circumstances, be used to save allocation costs. |
317 |
|
|
* |
318 |
|
|
* <p>Suppose <tt>x</tt> is a list known to contain only strings. |
319 |
|
|
* The following code can be used to dump the list into a newly |
320 |
|
|
* allocated array of <tt>String</tt>: |
321 |
|
|
* |
322 |
|
|
* <pre> |
323 |
|
|
* String[] y = x.toArray(new String[0]);</pre> |
324 |
|
|
* |
325 |
|
|
* Note that <tt>toArray(new Object[0])</tt> is identical in function to |
326 |
|
|
* <tt>toArray()</tt>. |
327 |
tim |
1.1 |
* |
328 |
|
|
* @param a the array into which the elements of the list are to |
329 |
jsr166 |
1.35 |
* be stored, if it is big enough; otherwise, a new array of the |
330 |
|
|
* same runtime type is allocated for this purpose. |
331 |
|
|
* @return an array containing all the elements in this list |
332 |
|
|
* @throws ArrayStoreException if the runtime type of the specified array |
333 |
|
|
* is not a supertype of the runtime type of every element in |
334 |
|
|
* this list |
335 |
|
|
* @throws NullPointerException if the specified array is null |
336 |
tim |
1.1 |
*/ |
337 |
|
|
public <T> T[] toArray(T a[]) { |
338 |
|
|
E[] elementData = array(); |
339 |
|
|
|
340 |
|
|
if (a.length < elementData.length) |
341 |
|
|
a = (T[]) |
342 |
|
|
java.lang.reflect.Array.newInstance(a.getClass().getComponentType(), |
343 |
|
|
elementData.length); |
344 |
|
|
|
345 |
|
|
System.arraycopy(elementData, 0, a, 0, elementData.length); |
346 |
|
|
|
347 |
|
|
if (a.length > elementData.length) |
348 |
|
|
a[elementData.length] = null; |
349 |
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|
|
350 |
|
|
return a; |
351 |
|
|
} |
352 |
|
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|
353 |
|
|
// Positional Access Operations |
354 |
|
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|
355 |
|
|
/** |
356 |
jsr166 |
1.35 |
* {@inheritDoc} |
357 |
tim |
1.1 |
* |
358 |
jsr166 |
1.35 |
* @throws IndexOutOfBoundsException {@inheritDoc} |
359 |
tim |
1.1 |
*/ |
360 |
|
|
public E get(int index) { |
361 |
|
|
E[] elementData = array(); |
362 |
|
|
rangeCheck(index, elementData.length); |
363 |
|
|
return elementData[index]; |
364 |
|
|
} |
365 |
|
|
|
366 |
|
|
/** |
367 |
jsr166 |
1.35 |
* Replaces the element at the specified position in this list with the |
368 |
|
|
* specified element. |
369 |
tim |
1.1 |
* |
370 |
jsr166 |
1.35 |
* @throws IndexOutOfBoundsException {@inheritDoc} |
371 |
tim |
1.1 |
*/ |
372 |
|
|
public synchronized E set(int index, E element) { |
373 |
dl |
1.12 |
int len = array.length; |
374 |
tim |
1.1 |
rangeCheck(index, len); |
375 |
dl |
1.12 |
E oldValue = array[index]; |
376 |
tim |
1.1 |
|
377 |
|
|
boolean same = (oldValue == element || |
378 |
|
|
(element != null && element.equals(oldValue))); |
379 |
|
|
if (!same) { |
380 |
tim |
1.7 |
E[] newArray = (E[]) new Object[len]; |
381 |
dl |
1.12 |
System.arraycopy(array, 0, newArray, 0, len); |
382 |
tim |
1.1 |
newArray[index] = element; |
383 |
dl |
1.12 |
array = newArray; |
384 |
tim |
1.1 |
} |
385 |
|
|
return oldValue; |
386 |
|
|
} |
387 |
|
|
|
388 |
|
|
/** |
389 |
|
|
* Appends the specified element to the end of this list. |
390 |
|
|
* |
391 |
jsr166 |
1.35 |
* @param element element to be appended to this list |
392 |
|
|
* @return <tt>true</tt> (as per the spec for {@link Collection#add}) |
393 |
tim |
1.1 |
*/ |
394 |
|
|
public synchronized boolean add(E element) { |
395 |
dl |
1.12 |
int len = array.length; |
396 |
tim |
1.7 |
E[] newArray = (E[]) new Object[len+1]; |
397 |
dl |
1.12 |
System.arraycopy(array, 0, newArray, 0, len); |
398 |
tim |
1.1 |
newArray[len] = element; |
399 |
dl |
1.12 |
array = newArray; |
400 |
tim |
1.1 |
return true; |
401 |
|
|
} |
402 |
|
|
|
403 |
|
|
/** |
404 |
|
|
* Inserts the specified element at the specified position in this |
405 |
|
|
* list. Shifts the element currently at that position (if any) and |
406 |
|
|
* any subsequent elements to the right (adds one to their indices). |
407 |
|
|
* |
408 |
jsr166 |
1.35 |
* @throws IndexOutOfBoundsException {@inheritDoc} |
409 |
tim |
1.1 |
*/ |
410 |
|
|
public synchronized void add(int index, E element) { |
411 |
dl |
1.12 |
int len = array.length; |
412 |
tim |
1.1 |
if (index > len || index < 0) |
413 |
|
|
throw new IndexOutOfBoundsException("Index: "+index+", Size: "+len); |
414 |
|
|
|
415 |
tim |
1.7 |
E[] newArray = (E[]) new Object[len+1]; |
416 |
dl |
1.12 |
System.arraycopy(array, 0, newArray, 0, index); |
417 |
tim |
1.1 |
newArray[index] = element; |
418 |
dl |
1.12 |
System.arraycopy(array, index, newArray, index+1, len - index); |
419 |
|
|
array = newArray; |
420 |
tim |
1.1 |
} |
421 |
|
|
|
422 |
|
|
/** |
423 |
|
|
* Removes the element at the specified position in this list. |
424 |
|
|
* Shifts any subsequent elements to the left (subtracts one from their |
425 |
jsr166 |
1.35 |
* indices). Returns the element that was removed from the list. |
426 |
tim |
1.1 |
* |
427 |
jsr166 |
1.35 |
* @throws IndexOutOfBoundsException {@inheritDoc} |
428 |
tim |
1.1 |
*/ |
429 |
|
|
public synchronized E remove(int index) { |
430 |
dl |
1.12 |
int len = array.length; |
431 |
tim |
1.1 |
rangeCheck(index, len); |
432 |
dl |
1.12 |
E oldValue = array[index]; |
433 |
tim |
1.7 |
E[] newArray = (E[]) new Object[len-1]; |
434 |
dl |
1.12 |
System.arraycopy(array, 0, newArray, 0, index); |
435 |
tim |
1.1 |
int numMoved = len - index - 1; |
436 |
|
|
if (numMoved > 0) |
437 |
dl |
1.12 |
System.arraycopy(array, index+1, newArray, index, numMoved); |
438 |
|
|
array = newArray; |
439 |
tim |
1.1 |
return oldValue; |
440 |
|
|
} |
441 |
|
|
|
442 |
|
|
/** |
443 |
jsr166 |
1.35 |
* Removes the first occurrence of the specified element from this list, |
444 |
|
|
* if it is present. If this list does not contain the element, it is |
445 |
|
|
* unchanged. More formally, removes the element with the lowest index |
446 |
|
|
* <tt>i</tt> such that |
447 |
|
|
* <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt> |
448 |
|
|
* (if such an element exists). Returns <tt>true</tt> if this list |
449 |
|
|
* contained the specified element (or equivalently, if this list |
450 |
|
|
* changed as a result of the call). |
451 |
tim |
1.1 |
* |
452 |
jsr166 |
1.35 |
* @param o element to be removed from this list, if present |
453 |
|
|
* @return <tt>true</tt> if this list contained the specified element |
454 |
tim |
1.1 |
*/ |
455 |
dl |
1.15 |
public synchronized boolean remove(Object o) { |
456 |
dl |
1.12 |
int len = array.length; |
457 |
tim |
1.1 |
if (len == 0) return false; |
458 |
|
|
|
459 |
|
|
// Copy while searching for element to remove |
460 |
|
|
// This wins in the normal case of element being present |
461 |
|
|
|
462 |
|
|
int newlen = len-1; |
463 |
tim |
1.7 |
E[] newArray = (E[]) new Object[newlen]; |
464 |
tim |
1.1 |
|
465 |
|
|
for (int i = 0; i < newlen; ++i) { |
466 |
dl |
1.15 |
if (o == array[i] || |
467 |
|
|
(o != null && o.equals(array[i]))) { |
468 |
tim |
1.1 |
// found one; copy remaining and exit |
469 |
dl |
1.12 |
for (int k = i + 1; k < len; ++k) newArray[k-1] = array[k]; |
470 |
|
|
array = newArray; |
471 |
tim |
1.1 |
return true; |
472 |
tim |
1.10 |
} else |
473 |
dl |
1.12 |
newArray[i] = array[i]; |
474 |
tim |
1.1 |
} |
475 |
|
|
// special handling for last cell |
476 |
|
|
|
477 |
dl |
1.15 |
if (o == array[newlen] || |
478 |
|
|
(o != null && o.equals(array[newlen]))) { |
479 |
dl |
1.12 |
array = newArray; |
480 |
tim |
1.1 |
return true; |
481 |
tim |
1.10 |
} else |
482 |
tim |
1.1 |
return false; // throw away copy |
483 |
|
|
} |
484 |
|
|
|
485 |
|
|
/** |
486 |
jsr166 |
1.35 |
* Removes from this list all of the elements whose index is between |
487 |
|
|
* <tt>fromIndex</tt>, inclusive, and <tt>toIndex</tt>, exclusive. |
488 |
|
|
* Shifts any succeeding elements to the left (reduces their index). |
489 |
dl |
1.15 |
* This call shortens the list by <tt>(toIndex - fromIndex)</tt> elements. |
490 |
|
|
* (If <tt>toIndex==fromIndex</tt>, this operation has no effect.) |
491 |
tim |
1.1 |
* |
492 |
jsr166 |
1.35 |
* @param fromIndex index of first element to be removed |
493 |
|
|
* @param toIndex index after last element to be removed |
494 |
dl |
1.29 |
* @throws IndexOutOfBoundsException if fromIndex or toIndex out of |
495 |
tim |
1.1 |
* range (fromIndex < 0 || fromIndex >= size() || toIndex |
496 |
jsr166 |
1.35 |
* > size() || toIndex < fromIndex) |
497 |
tim |
1.1 |
*/ |
498 |
|
|
private synchronized void removeRange(int fromIndex, int toIndex) { |
499 |
dl |
1.12 |
int len = array.length; |
500 |
tim |
1.1 |
|
501 |
|
|
if (fromIndex < 0 || fromIndex >= len || |
502 |
|
|
toIndex > len || toIndex < fromIndex) |
503 |
|
|
throw new IndexOutOfBoundsException(); |
504 |
|
|
|
505 |
|
|
int numMoved = len - toIndex; |
506 |
|
|
int newlen = len - (toIndex-fromIndex); |
507 |
tim |
1.7 |
E[] newArray = (E[]) new Object[newlen]; |
508 |
dl |
1.12 |
System.arraycopy(array, 0, newArray, 0, fromIndex); |
509 |
|
|
System.arraycopy(array, toIndex, newArray, fromIndex, numMoved); |
510 |
|
|
array = newArray; |
511 |
tim |
1.1 |
} |
512 |
|
|
|
513 |
|
|
/** |
514 |
|
|
* Append the element if not present. |
515 |
jsr166 |
1.35 |
* @param element element to be added to this list, if absent |
516 |
tim |
1.1 |
* @return true if added |
517 |
jsr166 |
1.30 |
*/ |
518 |
tim |
1.1 |
public synchronized boolean addIfAbsent(E element) { |
519 |
|
|
// Copy while checking if already present. |
520 |
|
|
// This wins in the most common case where it is not present |
521 |
dl |
1.12 |
int len = array.length; |
522 |
tim |
1.7 |
E[] newArray = (E[]) new Object[len + 1]; |
523 |
tim |
1.1 |
for (int i = 0; i < len; ++i) { |
524 |
dl |
1.12 |
if (element == array[i] || |
525 |
|
|
(element != null && element.equals(array[i]))) |
526 |
tim |
1.1 |
return false; // exit, throwing away copy |
527 |
|
|
else |
528 |
dl |
1.12 |
newArray[i] = array[i]; |
529 |
tim |
1.1 |
} |
530 |
|
|
newArray[len] = element; |
531 |
dl |
1.12 |
array = newArray; |
532 |
tim |
1.1 |
return true; |
533 |
|
|
} |
534 |
|
|
|
535 |
|
|
/** |
536 |
jsr166 |
1.35 |
* Returns <tt>true</tt> if this list contains all of the elements of the |
537 |
jsr166 |
1.32 |
* specified collection. |
538 |
jsr166 |
1.34 |
* |
539 |
jsr166 |
1.36 |
* @param c collection to be checked for containment in this list |
540 |
jsr166 |
1.35 |
* @return <tt>true</tt> if this list contains all of the elements of the |
541 |
|
|
* specified collection |
542 |
|
|
* @throws NullPointerException if the specified collection is null |
543 |
tim |
1.1 |
*/ |
544 |
tim |
1.7 |
public boolean containsAll(Collection<?> c) { |
545 |
tim |
1.1 |
E[] elementData = array(); |
546 |
|
|
int len = elementData.length; |
547 |
tim |
1.7 |
Iterator e = c.iterator(); |
548 |
tim |
1.1 |
while (e.hasNext()) |
549 |
dl |
1.20 |
if (indexOf(e.next(), elementData, len) < 0) |
550 |
tim |
1.1 |
return false; |
551 |
|
|
|
552 |
|
|
return true; |
553 |
|
|
} |
554 |
|
|
|
555 |
|
|
/** |
556 |
jsr166 |
1.32 |
* Removes from this list all of its elements that are contained in |
557 |
|
|
* the specified collection. This is a particularly expensive operation |
558 |
tim |
1.1 |
* in this class because of the need for an internal temporary array. |
559 |
|
|
* |
560 |
jsr166 |
1.35 |
* @param c collection containing elements to be removed from this list |
561 |
|
|
* @return <tt>true</tt> if this list changed as a result of the call |
562 |
|
|
* @throws ClassCastException {@inheritDoc} |
563 |
|
|
* @throws NullPointerException {@inheritDoc} |
564 |
tim |
1.1 |
*/ |
565 |
tim |
1.7 |
public synchronized boolean removeAll(Collection<?> c) { |
566 |
dl |
1.12 |
E[] elementData = array; |
567 |
tim |
1.1 |
int len = elementData.length; |
568 |
|
|
if (len == 0) return false; |
569 |
|
|
|
570 |
|
|
// temp array holds those elements we know we want to keep |
571 |
tim |
1.7 |
E[] temp = (E[]) new Object[len]; |
572 |
tim |
1.1 |
int newlen = 0; |
573 |
|
|
for (int i = 0; i < len; ++i) { |
574 |
|
|
E element = elementData[i]; |
575 |
|
|
if (!c.contains(element)) { |
576 |
|
|
temp[newlen++] = element; |
577 |
|
|
} |
578 |
|
|
} |
579 |
|
|
|
580 |
|
|
if (newlen == len) return false; |
581 |
|
|
|
582 |
|
|
// copy temp as new array |
583 |
tim |
1.7 |
E[] newArray = (E[]) new Object[newlen]; |
584 |
tim |
1.1 |
System.arraycopy(temp, 0, newArray, 0, newlen); |
585 |
dl |
1.12 |
array = newArray; |
586 |
tim |
1.1 |
return true; |
587 |
|
|
} |
588 |
|
|
|
589 |
|
|
/** |
590 |
jsr166 |
1.32 |
* Retains only the elements in this list that are contained in the |
591 |
jsr166 |
1.35 |
* specified collection. In other words, removes from this list all of |
592 |
|
|
* its elements that are not contained in the specified collection. |
593 |
jsr166 |
1.32 |
* |
594 |
jsr166 |
1.35 |
* @param c collection containing elements to be retained in this list |
595 |
|
|
* @return <tt>true</tt> if this list changed as a result of the call |
596 |
|
|
* @throws ClassCastException {@inheritDoc} |
597 |
|
|
* @throws NullPointerException {@inheritDoc} |
598 |
tim |
1.1 |
*/ |
599 |
tim |
1.7 |
public synchronized boolean retainAll(Collection<?> c) { |
600 |
dl |
1.12 |
E[] elementData = array; |
601 |
tim |
1.1 |
int len = elementData.length; |
602 |
|
|
if (len == 0) return false; |
603 |
|
|
|
604 |
tim |
1.7 |
E[] temp = (E[]) new Object[len]; |
605 |
tim |
1.1 |
int newlen = 0; |
606 |
|
|
for (int i = 0; i < len; ++i) { |
607 |
|
|
E element = elementData[i]; |
608 |
|
|
if (c.contains(element)) { |
609 |
|
|
temp[newlen++] = element; |
610 |
|
|
} |
611 |
|
|
} |
612 |
|
|
|
613 |
|
|
if (newlen == len) return false; |
614 |
|
|
|
615 |
tim |
1.7 |
E[] newArray = (E[]) new Object[newlen]; |
616 |
tim |
1.1 |
System.arraycopy(temp, 0, newArray, 0, newlen); |
617 |
dl |
1.12 |
array = newArray; |
618 |
tim |
1.1 |
return true; |
619 |
|
|
} |
620 |
|
|
|
621 |
|
|
/** |
622 |
jsr166 |
1.32 |
* Appends all of the elements in the specified collection that |
623 |
tim |
1.1 |
* are not already contained in this list, to the end of |
624 |
|
|
* this list, in the order that they are returned by the |
625 |
jsr166 |
1.32 |
* specified collection's iterator. |
626 |
tim |
1.1 |
* |
627 |
jsr166 |
1.36 |
* @param c collection containing elements to be added to this list |
628 |
tim |
1.1 |
* @return the number of elements added |
629 |
jsr166 |
1.35 |
* @throws NullPointerException if the specified collection is null |
630 |
tim |
1.1 |
*/ |
631 |
tim |
1.7 |
public synchronized int addAllAbsent(Collection<? extends E> c) { |
632 |
tim |
1.1 |
int numNew = c.size(); |
633 |
|
|
if (numNew == 0) return 0; |
634 |
|
|
|
635 |
dl |
1.12 |
E[] elementData = array; |
636 |
tim |
1.1 |
int len = elementData.length; |
637 |
|
|
|
638 |
tim |
1.7 |
E[] temp = (E[]) new Object[numNew]; |
639 |
tim |
1.1 |
int added = 0; |
640 |
dl |
1.20 |
Iterator<? extends E> e = c.iterator(); |
641 |
tim |
1.1 |
while (e.hasNext()) { |
642 |
dl |
1.20 |
E element = e.next(); |
643 |
tim |
1.1 |
if (indexOf(element, elementData, len) < 0) { |
644 |
|
|
if (indexOf(element, temp, added) < 0) { |
645 |
|
|
temp[added++] = element; |
646 |
|
|
} |
647 |
|
|
} |
648 |
|
|
} |
649 |
|
|
|
650 |
|
|
if (added == 0) return 0; |
651 |
|
|
|
652 |
tim |
1.7 |
E[] newArray = (E[]) new Object[len+added]; |
653 |
tim |
1.1 |
System.arraycopy(elementData, 0, newArray, 0, len); |
654 |
|
|
System.arraycopy(temp, 0, newArray, len, added); |
655 |
dl |
1.12 |
array = newArray; |
656 |
tim |
1.1 |
return added; |
657 |
|
|
} |
658 |
|
|
|
659 |
|
|
/** |
660 |
|
|
* Removes all of the elements from this list. |
661 |
|
|
* |
662 |
|
|
*/ |
663 |
|
|
public synchronized void clear() { |
664 |
dl |
1.12 |
array = (E[]) new Object[0]; |
665 |
tim |
1.1 |
} |
666 |
|
|
|
667 |
|
|
/** |
668 |
jsr166 |
1.32 |
* Appends all of the elements in the specified collection to the end |
669 |
|
|
* of this list, in the order that they are returned by the specified |
670 |
|
|
* collection's iterator. |
671 |
tim |
1.1 |
* |
672 |
jsr166 |
1.36 |
* @param c collection containing elements to be added to this list |
673 |
dl |
1.6 |
* @return true if any elements are added |
674 |
jsr166 |
1.35 |
* @throws NullPointerException if the specified collection is null |
675 |
tim |
1.1 |
*/ |
676 |
tim |
1.7 |
public synchronized boolean addAll(Collection<? extends E> c) { |
677 |
tim |
1.1 |
int numNew = c.size(); |
678 |
|
|
if (numNew == 0) return false; |
679 |
|
|
|
680 |
dl |
1.12 |
int len = array.length; |
681 |
tim |
1.7 |
E[] newArray = (E[]) new Object[len+numNew]; |
682 |
dl |
1.12 |
System.arraycopy(array, 0, newArray, 0, len); |
683 |
dl |
1.20 |
Iterator<? extends E> e = c.iterator(); |
684 |
tim |
1.1 |
for (int i=0; i<numNew; i++) |
685 |
dl |
1.20 |
newArray[len++] = e.next(); |
686 |
dl |
1.12 |
array = newArray; |
687 |
tim |
1.1 |
|
688 |
|
|
return true; |
689 |
|
|
} |
690 |
|
|
|
691 |
|
|
/** |
692 |
jsr166 |
1.35 |
* Inserts all of the elements in the specified collection into this |
693 |
tim |
1.1 |
* list, starting at the specified position. Shifts the element |
694 |
|
|
* currently at that position (if any) and any subsequent elements to |
695 |
|
|
* the right (increases their indices). The new elements will appear |
696 |
|
|
* in the list in the order that they are returned by the |
697 |
|
|
* specified Collection's iterator. |
698 |
|
|
* |
699 |
jsr166 |
1.35 |
* @param index index at which to insert the first element |
700 |
|
|
* from the specified collection |
701 |
jsr166 |
1.36 |
* @param c collection containing elements to be added to this list |
702 |
jsr166 |
1.35 |
* @return <tt>true</tt> if this list changed as a result of the call |
703 |
|
|
* @throws IndexOutOfBoundsException {@inheritDoc} |
704 |
|
|
* @throws NullPointerException if the specified collection is null |
705 |
tim |
1.1 |
*/ |
706 |
tim |
1.7 |
public synchronized boolean addAll(int index, Collection<? extends E> c) { |
707 |
dl |
1.12 |
int len = array.length; |
708 |
tim |
1.1 |
if (index > len || index < 0) |
709 |
|
|
throw new IndexOutOfBoundsException("Index: "+index+", Size: "+len); |
710 |
|
|
|
711 |
|
|
int numNew = c.size(); |
712 |
|
|
if (numNew == 0) return false; |
713 |
|
|
|
714 |
tim |
1.7 |
E[] newArray = (E[]) new Object[len+numNew]; |
715 |
dl |
1.12 |
System.arraycopy(array, 0, newArray, 0, len); |
716 |
tim |
1.1 |
int numMoved = len - index; |
717 |
|
|
if (numMoved > 0) |
718 |
dl |
1.12 |
System.arraycopy(array, index, newArray, index + numNew, numMoved); |
719 |
dl |
1.20 |
Iterator<? extends E> e = c.iterator(); |
720 |
tim |
1.1 |
for (int i=0; i<numNew; i++) |
721 |
dl |
1.20 |
newArray[index++] = e.next(); |
722 |
dl |
1.12 |
array = newArray; |
723 |
tim |
1.1 |
|
724 |
|
|
return true; |
725 |
|
|
} |
726 |
|
|
|
727 |
|
|
/** |
728 |
jsr166 |
1.30 |
* Checks if the given index is in range. If not, throws an appropriate |
729 |
tim |
1.1 |
* runtime exception. |
730 |
|
|
*/ |
731 |
|
|
private void rangeCheck(int index, int length) { |
732 |
|
|
if (index >= length || index < 0) |
733 |
|
|
throw new IndexOutOfBoundsException("Index: "+index+", Size: "+ length); |
734 |
|
|
} |
735 |
|
|
|
736 |
|
|
/** |
737 |
|
|
* Save the state of the list to a stream (i.e., serialize it). |
738 |
|
|
* |
739 |
|
|
* @serialData The length of the array backing the list is emitted |
740 |
|
|
* (int), followed by all of its elements (each an Object) |
741 |
|
|
* in the proper order. |
742 |
dl |
1.6 |
* @param s the stream |
743 |
tim |
1.1 |
*/ |
744 |
|
|
private void writeObject(java.io.ObjectOutputStream s) |
745 |
|
|
throws java.io.IOException{ |
746 |
|
|
|
747 |
|
|
// Write out element count, and any hidden stuff |
748 |
|
|
s.defaultWriteObject(); |
749 |
|
|
|
750 |
|
|
E[] elementData = array(); |
751 |
|
|
// Write out array length |
752 |
|
|
s.writeInt(elementData.length); |
753 |
|
|
|
754 |
|
|
// Write out all elements in the proper order. |
755 |
|
|
for (int i=0; i<elementData.length; i++) |
756 |
|
|
s.writeObject(elementData[i]); |
757 |
|
|
} |
758 |
|
|
|
759 |
|
|
/** |
760 |
|
|
* Reconstitute the list from a stream (i.e., deserialize it). |
761 |
dl |
1.6 |
* @param s the stream |
762 |
tim |
1.1 |
*/ |
763 |
dl |
1.12 |
private void readObject(java.io.ObjectInputStream s) |
764 |
tim |
1.1 |
throws java.io.IOException, ClassNotFoundException { |
765 |
|
|
|
766 |
|
|
// Read in size, and any hidden stuff |
767 |
|
|
s.defaultReadObject(); |
768 |
|
|
|
769 |
|
|
// Read in array length and allocate array |
770 |
|
|
int arrayLength = s.readInt(); |
771 |
tim |
1.7 |
E[] elementData = (E[]) new Object[arrayLength]; |
772 |
tim |
1.1 |
|
773 |
|
|
// Read in all elements in the proper order. |
774 |
|
|
for (int i=0; i<elementData.length; i++) |
775 |
|
|
elementData[i] = (E) s.readObject(); |
776 |
dl |
1.12 |
array = elementData; |
777 |
tim |
1.1 |
} |
778 |
|
|
|
779 |
|
|
/** |
780 |
jsr166 |
1.32 |
* Returns a string representation of this list, containing |
781 |
tim |
1.1 |
* the String representation of each element. |
782 |
|
|
*/ |
783 |
|
|
public String toString() { |
784 |
|
|
StringBuffer buf = new StringBuffer(); |
785 |
|
|
Iterator e = iterator(); |
786 |
|
|
buf.append("["); |
787 |
|
|
int maxIndex = size() - 1; |
788 |
|
|
for (int i = 0; i <= maxIndex; i++) { |
789 |
|
|
buf.append(String.valueOf(e.next())); |
790 |
|
|
if (i < maxIndex) |
791 |
|
|
buf.append(", "); |
792 |
|
|
} |
793 |
|
|
buf.append("]"); |
794 |
|
|
return buf.toString(); |
795 |
|
|
} |
796 |
|
|
|
797 |
|
|
/** |
798 |
jsr166 |
1.35 |
* Compares the specified object with this list for equality. |
799 |
|
|
* Returns true if and only if the specified object is also a {@link |
800 |
|
|
* List}, both lists have the same size, and all corresponding pairs |
801 |
|
|
* of elements in the two lists are <em>equal</em>. (Two elements |
802 |
|
|
* <tt>e1</tt> and <tt>e2</tt> are <em>equal</em> if <tt>(e1==null ? |
803 |
|
|
* e2==null : e1.equals(e2))</tt>.) In other words, two lists are |
804 |
|
|
* defined to be equal if they contain the same elements in the same |
805 |
|
|
* order. |
806 |
tim |
1.1 |
* |
807 |
jsr166 |
1.35 |
* @param o the object to be compared for equality with this list |
808 |
|
|
* @return <tt>true</tt> if the specified object is equal to this list |
809 |
tim |
1.1 |
*/ |
810 |
|
|
public boolean equals(Object o) { |
811 |
|
|
if (o == this) |
812 |
|
|
return true; |
813 |
|
|
if (!(o instanceof List)) |
814 |
|
|
return false; |
815 |
|
|
|
816 |
tim |
1.8 |
List<E> l2 = (List<E>)(o); |
817 |
tim |
1.1 |
if (size() != l2.size()) |
818 |
|
|
return false; |
819 |
|
|
|
820 |
|
|
ListIterator<E> e1 = listIterator(); |
821 |
|
|
ListIterator<E> e2 = l2.listIterator(); |
822 |
jsr166 |
1.35 |
while (e1.hasNext()) { |
823 |
tim |
1.1 |
E o1 = e1.next(); |
824 |
|
|
E o2 = e2.next(); |
825 |
|
|
if (!(o1==null ? o2==null : o1.equals(o2))) |
826 |
|
|
return false; |
827 |
|
|
} |
828 |
|
|
return true; |
829 |
|
|
} |
830 |
|
|
|
831 |
|
|
/** |
832 |
jsr166 |
1.35 |
* Returns the hash code value for this list. |
833 |
dl |
1.26 |
* |
834 |
|
|
* <p> This implementation uses the definition in {@link |
835 |
|
|
* List#hashCode}. |
836 |
dl |
1.15 |
* @return the hash code |
837 |
tim |
1.1 |
*/ |
838 |
|
|
public int hashCode() { |
839 |
|
|
int hashCode = 1; |
840 |
|
|
Iterator<E> i = iterator(); |
841 |
|
|
while (i.hasNext()) { |
842 |
|
|
E obj = i.next(); |
843 |
|
|
hashCode = 31*hashCode + (obj==null ? 0 : obj.hashCode()); |
844 |
|
|
} |
845 |
|
|
return hashCode; |
846 |
|
|
} |
847 |
|
|
|
848 |
|
|
/** |
849 |
jsr166 |
1.35 |
* Returns an iterator over the elements in this list in proper sequence. |
850 |
|
|
* |
851 |
|
|
* <p>The returned iterator provides a snapshot of the state of the list |
852 |
|
|
* when the iterator was constructed. No synchronization is needed while |
853 |
|
|
* traversing the iterator. The iterator does <em>NOT</em> support the |
854 |
|
|
* <tt>remove</tt> method. |
855 |
|
|
* |
856 |
|
|
* @return an iterator over the elements in this list in proper sequence |
857 |
tim |
1.1 |
*/ |
858 |
|
|
public Iterator<E> iterator() { |
859 |
|
|
return new COWIterator<E>(array(), 0); |
860 |
|
|
} |
861 |
|
|
|
862 |
|
|
/** |
863 |
jsr166 |
1.35 |
* {@inheritDoc} |
864 |
tim |
1.1 |
* |
865 |
jsr166 |
1.35 |
* <p>The returned iterator provides a snapshot of the state of the list |
866 |
|
|
* when the iterator was constructed. No synchronization is needed while |
867 |
|
|
* traversing the iterator. The iterator does <em>NOT</em> support the |
868 |
|
|
* <tt>remove</tt>, <tt>set</tt> or <tt>add</tt> methods. |
869 |
tim |
1.1 |
*/ |
870 |
|
|
public ListIterator<E> listIterator() { |
871 |
|
|
return new COWIterator<E>(array(), 0); |
872 |
|
|
} |
873 |
|
|
|
874 |
|
|
/** |
875 |
jsr166 |
1.35 |
* {@inheritDoc} |
876 |
|
|
* |
877 |
|
|
* <p>The list iterator returned by this implementation will throw an |
878 |
|
|
* <tt>UnsupportedOperationException</tt> in its <tt>remove</tt>, |
879 |
|
|
* <tt>set</tt> and <tt>add</tt> methods. |
880 |
|
|
* |
881 |
|
|
* @throws IndexOutOfBoundsException {@inheritDoc} |
882 |
tim |
1.1 |
*/ |
883 |
|
|
public ListIterator<E> listIterator(final int index) { |
884 |
|
|
E[] elementData = array(); |
885 |
|
|
int len = elementData.length; |
886 |
|
|
if (index<0 || index>len) |
887 |
|
|
throw new IndexOutOfBoundsException("Index: "+index); |
888 |
|
|
|
889 |
|
|
return new COWIterator<E>(array(), index); |
890 |
|
|
} |
891 |
|
|
|
892 |
|
|
private static class COWIterator<E> implements ListIterator<E> { |
893 |
|
|
|
894 |
|
|
/** Snapshot of the array **/ |
895 |
|
|
private final E[] array; |
896 |
|
|
|
897 |
|
|
/** |
898 |
|
|
* Index of element to be returned by subsequent call to next. |
899 |
|
|
*/ |
900 |
|
|
private int cursor; |
901 |
|
|
|
902 |
|
|
private COWIterator(E[] elementArray, int initialCursor) { |
903 |
|
|
array = elementArray; |
904 |
|
|
cursor = initialCursor; |
905 |
|
|
} |
906 |
|
|
|
907 |
|
|
public boolean hasNext() { |
908 |
|
|
return cursor < array.length; |
909 |
|
|
} |
910 |
|
|
|
911 |
|
|
public boolean hasPrevious() { |
912 |
|
|
return cursor > 0; |
913 |
|
|
} |
914 |
|
|
|
915 |
|
|
public E next() { |
916 |
|
|
try { |
917 |
|
|
return array[cursor++]; |
918 |
tim |
1.10 |
} catch (IndexOutOfBoundsException ex) { |
919 |
tim |
1.1 |
throw new NoSuchElementException(); |
920 |
|
|
} |
921 |
|
|
} |
922 |
|
|
|
923 |
|
|
public E previous() { |
924 |
|
|
try { |
925 |
|
|
return array[--cursor]; |
926 |
jsr166 |
1.30 |
} catch (IndexOutOfBoundsException e) { |
927 |
tim |
1.1 |
throw new NoSuchElementException(); |
928 |
|
|
} |
929 |
|
|
} |
930 |
|
|
|
931 |
|
|
public int nextIndex() { |
932 |
|
|
return cursor; |
933 |
|
|
} |
934 |
|
|
|
935 |
|
|
public int previousIndex() { |
936 |
|
|
return cursor-1; |
937 |
|
|
} |
938 |
|
|
|
939 |
|
|
/** |
940 |
|
|
* Not supported. Always throws UnsupportedOperationException. |
941 |
jsr166 |
1.32 |
* @throws UnsupportedOperationException always; <tt>remove</tt> |
942 |
|
|
* is not supported by this iterator. |
943 |
tim |
1.1 |
*/ |
944 |
|
|
public void remove() { |
945 |
|
|
throw new UnsupportedOperationException(); |
946 |
|
|
} |
947 |
|
|
|
948 |
|
|
/** |
949 |
|
|
* Not supported. Always throws UnsupportedOperationException. |
950 |
jsr166 |
1.32 |
* @throws UnsupportedOperationException always; <tt>set</tt> |
951 |
|
|
* is not supported by this iterator. |
952 |
tim |
1.1 |
*/ |
953 |
jsr166 |
1.33 |
public void set(E e) { |
954 |
tim |
1.1 |
throw new UnsupportedOperationException(); |
955 |
|
|
} |
956 |
|
|
|
957 |
|
|
/** |
958 |
|
|
* Not supported. Always throws UnsupportedOperationException. |
959 |
jsr166 |
1.32 |
* @throws UnsupportedOperationException always; <tt>add</tt> |
960 |
|
|
* is not supported by this iterator. |
961 |
tim |
1.1 |
*/ |
962 |
jsr166 |
1.33 |
public void add(E e) { |
963 |
tim |
1.1 |
throw new UnsupportedOperationException(); |
964 |
|
|
} |
965 |
|
|
} |
966 |
|
|
|
967 |
|
|
/** |
968 |
jsr166 |
1.35 |
* Returns a view of the portion of this list between <tt>fromIndex</tt>, |
969 |
|
|
* inclusive, and <tt>toIndex</tt>, exclusive. The returned list is |
970 |
|
|
* backed by this list, so changes in the returned list are reflected in |
971 |
|
|
* this list, and vice-versa. While mutative operations are supported, |
972 |
|
|
* they are probably not very useful for CopyOnWriteArrayLists. |
973 |
|
|
* |
974 |
|
|
* <p>The semantics of the list returned by this method become undefined if |
975 |
|
|
* the backing list (i.e., this list) is <i>structurally modified</i> in |
976 |
|
|
* any way other than via the returned list. (Structural modifications are |
977 |
|
|
* those that change the size of the list, or otherwise perturb it in such |
978 |
tim |
1.1 |
* a fashion that iterations in progress may yield incorrect results.) |
979 |
|
|
* |
980 |
jsr166 |
1.35 |
* @param fromIndex low endpoint (inclusive) of the subList |
981 |
|
|
* @param toIndex high endpoint (exclusive) of the subList |
982 |
|
|
* @return a view of the specified range within this list |
983 |
|
|
* @throws IndexOutOfBoundsException {@inheritDoc} |
984 |
tim |
1.1 |
*/ |
985 |
|
|
public synchronized List<E> subList(int fromIndex, int toIndex) { |
986 |
dl |
1.21 |
// synchronized since sublist constructor depends on it. |
987 |
dl |
1.12 |
int len = array.length; |
988 |
tim |
1.1 |
if (fromIndex<0 || toIndex>len || fromIndex>toIndex) |
989 |
|
|
throw new IndexOutOfBoundsException(); |
990 |
|
|
return new COWSubList<E>(this, fromIndex, toIndex); |
991 |
|
|
} |
992 |
|
|
|
993 |
|
|
private static class COWSubList<E> extends AbstractList<E> { |
994 |
|
|
|
995 |
|
|
/* |
996 |
dl |
1.2 |
This class extends AbstractList merely for convenience, to |
997 |
|
|
avoid having to define addAll, etc. This doesn't hurt, but |
998 |
|
|
is wasteful. This class does not need or use modCount |
999 |
|
|
mechanics in AbstractList, but does need to check for |
1000 |
|
|
concurrent modification using similar mechanics. On each |
1001 |
|
|
operation, the array that we expect the backing list to use |
1002 |
|
|
is checked and updated. Since we do this for all of the |
1003 |
|
|
base operations invoked by those defined in AbstractList, |
1004 |
|
|
all is well. While inefficient, this is not worth |
1005 |
|
|
improving. The kinds of list operations inherited from |
1006 |
dl |
1.20 |
AbstractList are already so slow on COW sublists that |
1007 |
dl |
1.2 |
adding a bit more space/time doesn't seem even noticeable. |
1008 |
tim |
1.1 |
*/ |
1009 |
|
|
|
1010 |
|
|
private final CopyOnWriteArrayList<E> l; |
1011 |
|
|
private final int offset; |
1012 |
|
|
private int size; |
1013 |
|
|
private E[] expectedArray; |
1014 |
|
|
|
1015 |
|
|
private COWSubList(CopyOnWriteArrayList<E> list, |
1016 |
|
|
int fromIndex, int toIndex) { |
1017 |
|
|
l = list; |
1018 |
|
|
expectedArray = l.array(); |
1019 |
|
|
offset = fromIndex; |
1020 |
|
|
size = toIndex - fromIndex; |
1021 |
|
|
} |
1022 |
|
|
|
1023 |
|
|
// only call this holding l's lock |
1024 |
|
|
private void checkForComodification() { |
1025 |
dl |
1.12 |
if (l.array != expectedArray) |
1026 |
tim |
1.1 |
throw new ConcurrentModificationException(); |
1027 |
|
|
} |
1028 |
|
|
|
1029 |
|
|
// only call this holding l's lock |
1030 |
|
|
private void rangeCheck(int index) { |
1031 |
|
|
if (index<0 || index>=size) |
1032 |
|
|
throw new IndexOutOfBoundsException("Index: "+index+ ",Size: "+size); |
1033 |
|
|
} |
1034 |
|
|
|
1035 |
|
|
|
1036 |
|
|
public E set(int index, E element) { |
1037 |
|
|
synchronized(l) { |
1038 |
|
|
rangeCheck(index); |
1039 |
|
|
checkForComodification(); |
1040 |
|
|
E x = l.set(index+offset, element); |
1041 |
dl |
1.12 |
expectedArray = l.array; |
1042 |
tim |
1.1 |
return x; |
1043 |
|
|
} |
1044 |
|
|
} |
1045 |
|
|
|
1046 |
|
|
public E get(int index) { |
1047 |
|
|
synchronized(l) { |
1048 |
|
|
rangeCheck(index); |
1049 |
|
|
checkForComodification(); |
1050 |
|
|
return l.get(index+offset); |
1051 |
|
|
} |
1052 |
|
|
} |
1053 |
|
|
|
1054 |
|
|
public int size() { |
1055 |
|
|
synchronized(l) { |
1056 |
|
|
checkForComodification(); |
1057 |
|
|
return size; |
1058 |
|
|
} |
1059 |
|
|
} |
1060 |
|
|
|
1061 |
|
|
public void add(int index, E element) { |
1062 |
|
|
synchronized(l) { |
1063 |
|
|
checkForComodification(); |
1064 |
|
|
if (index<0 || index>size) |
1065 |
|
|
throw new IndexOutOfBoundsException(); |
1066 |
|
|
l.add(index+offset, element); |
1067 |
dl |
1.12 |
expectedArray = l.array; |
1068 |
tim |
1.1 |
size++; |
1069 |
|
|
} |
1070 |
|
|
} |
1071 |
|
|
|
1072 |
dl |
1.13 |
public void clear() { |
1073 |
|
|
synchronized(l) { |
1074 |
|
|
checkForComodification(); |
1075 |
|
|
l.removeRange(offset, offset+size); |
1076 |
|
|
expectedArray = l.array; |
1077 |
|
|
size = 0; |
1078 |
|
|
} |
1079 |
|
|
} |
1080 |
|
|
|
1081 |
tim |
1.1 |
public E remove(int index) { |
1082 |
|
|
synchronized(l) { |
1083 |
|
|
rangeCheck(index); |
1084 |
|
|
checkForComodification(); |
1085 |
|
|
E result = l.remove(index+offset); |
1086 |
dl |
1.12 |
expectedArray = l.array; |
1087 |
tim |
1.1 |
size--; |
1088 |
|
|
return result; |
1089 |
|
|
} |
1090 |
|
|
} |
1091 |
|
|
|
1092 |
|
|
public Iterator<E> iterator() { |
1093 |
|
|
synchronized(l) { |
1094 |
|
|
checkForComodification(); |
1095 |
tim |
1.8 |
return new COWSubListIterator<E>(l, 0, offset, size); |
1096 |
tim |
1.1 |
} |
1097 |
|
|
} |
1098 |
|
|
|
1099 |
|
|
public ListIterator<E> listIterator(final int index) { |
1100 |
|
|
synchronized(l) { |
1101 |
|
|
checkForComodification(); |
1102 |
|
|
if (index<0 || index>size) |
1103 |
|
|
throw new IndexOutOfBoundsException("Index: "+index+", Size: "+size); |
1104 |
tim |
1.8 |
return new COWSubListIterator<E>(l, index, offset, size); |
1105 |
tim |
1.1 |
} |
1106 |
|
|
} |
1107 |
|
|
|
1108 |
tim |
1.7 |
public List<E> subList(int fromIndex, int toIndex) { |
1109 |
|
|
synchronized(l) { |
1110 |
|
|
checkForComodification(); |
1111 |
|
|
if (fromIndex<0 || toIndex>size) |
1112 |
|
|
throw new IndexOutOfBoundsException(); |
1113 |
|
|
return new COWSubList<E>(l, fromIndex+offset, toIndex+offset); |
1114 |
tim |
1.1 |
} |
1115 |
tim |
1.7 |
} |
1116 |
tim |
1.1 |
|
1117 |
tim |
1.7 |
} |
1118 |
tim |
1.1 |
|
1119 |
|
|
|
1120 |
tim |
1.7 |
private static class COWSubListIterator<E> implements ListIterator<E> { |
1121 |
|
|
private final ListIterator<E> i; |
1122 |
|
|
private final int index; |
1123 |
|
|
private final int offset; |
1124 |
|
|
private final int size; |
1125 |
|
|
private COWSubListIterator(List<E> l, int index, int offset, int size) { |
1126 |
|
|
this.index = index; |
1127 |
|
|
this.offset = offset; |
1128 |
|
|
this.size = size; |
1129 |
|
|
i = l.listIterator(index+offset); |
1130 |
|
|
} |
1131 |
tim |
1.1 |
|
1132 |
tim |
1.7 |
public boolean hasNext() { |
1133 |
|
|
return nextIndex() < size; |
1134 |
|
|
} |
1135 |
tim |
1.1 |
|
1136 |
tim |
1.7 |
public E next() { |
1137 |
|
|
if (hasNext()) |
1138 |
|
|
return i.next(); |
1139 |
|
|
else |
1140 |
|
|
throw new NoSuchElementException(); |
1141 |
|
|
} |
1142 |
tim |
1.1 |
|
1143 |
tim |
1.7 |
public boolean hasPrevious() { |
1144 |
|
|
return previousIndex() >= 0; |
1145 |
|
|
} |
1146 |
tim |
1.1 |
|
1147 |
tim |
1.7 |
public E previous() { |
1148 |
|
|
if (hasPrevious()) |
1149 |
|
|
return i.previous(); |
1150 |
|
|
else |
1151 |
|
|
throw new NoSuchElementException(); |
1152 |
|
|
} |
1153 |
tim |
1.1 |
|
1154 |
tim |
1.7 |
public int nextIndex() { |
1155 |
|
|
return i.nextIndex() - offset; |
1156 |
|
|
} |
1157 |
tim |
1.1 |
|
1158 |
tim |
1.7 |
public int previousIndex() { |
1159 |
|
|
return i.previousIndex() - offset; |
1160 |
tim |
1.1 |
} |
1161 |
|
|
|
1162 |
tim |
1.7 |
public void remove() { |
1163 |
|
|
throw new UnsupportedOperationException(); |
1164 |
|
|
} |
1165 |
tim |
1.1 |
|
1166 |
jsr166 |
1.33 |
public void set(E e) { |
1167 |
tim |
1.7 |
throw new UnsupportedOperationException(); |
1168 |
tim |
1.1 |
} |
1169 |
|
|
|
1170 |
jsr166 |
1.33 |
public void add(E e) { |
1171 |
tim |
1.7 |
throw new UnsupportedOperationException(); |
1172 |
|
|
} |
1173 |
tim |
1.1 |
} |
1174 |
|
|
|
1175 |
|
|
} |