author | dl |
Thu, 20 Dec 2012 13:44:06 +0000 | |
changeset 14914 | 69bfd88e3ea1 |
parent 14325 | 622c473a21aa |
child 15020 | 50394fa17c1b |
permissions | -rw-r--r-- |
2 | 1 |
/* |
2 |
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
|
3 |
* |
|
4 |
* This code is free software; you can redistribute it and/or modify it |
|
5 |
* under the terms of the GNU General Public License version 2 only, as |
|
5506 | 6 |
* published by the Free Software Foundation. Oracle designates this |
2 | 7 |
* particular file as subject to the "Classpath" exception as provided |
5506 | 8 |
* by Oracle in the LICENSE file that accompanied this code. |
2 | 9 |
* |
10 |
* This code is distributed in the hope that it will be useful, but WITHOUT |
|
11 |
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
|
12 |
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
|
13 |
* version 2 for more details (a copy is included in the LICENSE file that |
|
14 |
* accompanied this code). |
|
15 |
* |
|
16 |
* You should have received a copy of the GNU General Public License version |
|
17 |
* 2 along with this work; if not, write to the Free Software Foundation, |
|
18 |
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
|
19 |
* |
|
5506 | 20 |
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
21 |
* or visit www.oracle.com if you need additional information or have any |
|
22 |
* questions. |
|
2 | 23 |
*/ |
24 |
||
25 |
/* |
|
26 |
* This file is available under and governed by the GNU General Public |
|
27 |
* License version 2 only, as published by the Free Software Foundation. |
|
28 |
* However, the following notice accompanied the original version of this |
|
29 |
* file: |
|
30 |
* |
|
31 |
* Written by Doug Lea with assistance from members of JCP JSR-166 |
|
32 |
* Expert Group and released to the public domain, as explained at |
|
9242
ef138d47df58
7034657: Update Creative Commons license URL in legal notices
dl
parents:
7976
diff
changeset
|
33 |
* http://creativecommons.org/publicdomain/zero/1.0/ |
2 | 34 |
*/ |
35 |
||
36 |
package java.util.concurrent.atomic; |
|
11892
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
37 |
|
14325
622c473a21aa
8001575: Minor/sync/cleanup j.u.c with Dougs CVS - Oct 2012
dl
parents:
11902
diff
changeset
|
38 |
import java.util.Arrays; |
11892
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
39 |
import java.lang.reflect.Array; |
2 | 40 |
import sun.misc.Unsafe; |
41 |
||
42 |
/** |
|
43 |
* An array of object references in which elements may be updated |
|
44 |
* atomically. See the {@link java.util.concurrent.atomic} package |
|
45 |
* specification for description of the properties of atomic |
|
46 |
* variables. |
|
47 |
* @since 1.5 |
|
48 |
* @author Doug Lea |
|
49 |
* @param <E> The base class of elements held in this array |
|
50 |
*/ |
|
51 |
public class AtomicReferenceArray<E> implements java.io.Serializable { |
|
52 |
private static final long serialVersionUID = -6209656149925076980L; |
|
53 |
||
11892
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
54 |
private static final Unsafe unsafe; |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
55 |
private static final int base; |
7976
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
56 |
private static final int shift; |
11892
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
57 |
private static final long arrayFieldOffset; |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
58 |
private final Object[] array; // must have exact type Object[] |
2 | 59 |
|
7976
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
60 |
static { |
11892
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
61 |
int scale; |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
62 |
try { |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
63 |
unsafe = Unsafe.getUnsafe(); |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
64 |
arrayFieldOffset = unsafe.objectFieldOffset |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
65 |
(AtomicReferenceArray.class.getDeclaredField("array")); |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
66 |
base = unsafe.arrayBaseOffset(Object[].class); |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
67 |
scale = unsafe.arrayIndexScale(Object[].class); |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
68 |
} catch (Exception e) { |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
69 |
throw new Error(e); |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
70 |
} |
7976
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
71 |
if ((scale & (scale - 1)) != 0) |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
72 |
throw new Error("data type scale not a power of two"); |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
73 |
shift = 31 - Integer.numberOfLeadingZeros(scale); |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
74 |
} |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
75 |
|
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
76 |
private long checkedByteOffset(int i) { |
2 | 77 |
if (i < 0 || i >= array.length) |
78 |
throw new IndexOutOfBoundsException("index " + i); |
|
7976
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
79 |
|
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
80 |
return byteOffset(i); |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
81 |
} |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
82 |
|
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
83 |
private static long byteOffset(int i) { |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
84 |
return ((long) i << shift) + base; |
2 | 85 |
} |
86 |
||
87 |
/** |
|
7976
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
88 |
* Creates a new AtomicReferenceArray of the given length, with all |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
89 |
* elements initially null. |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
90 |
* |
2 | 91 |
* @param length the length of the array |
92 |
*/ |
|
93 |
public AtomicReferenceArray(int length) { |
|
94 |
array = new Object[length]; |
|
95 |
} |
|
96 |
||
97 |
/** |
|
98 |
* Creates a new AtomicReferenceArray with the same length as, and |
|
99 |
* all elements copied from, the given array. |
|
100 |
* |
|
101 |
* @param array the array to copy elements from |
|
102 |
* @throws NullPointerException if array is null |
|
103 |
*/ |
|
104 |
public AtomicReferenceArray(E[] array) { |
|
7976
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
105 |
// Visibility guaranteed by final field guarantees |
11892
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
106 |
this.array = Arrays.copyOf(array, array.length, Object[].class); |
2 | 107 |
} |
108 |
||
109 |
/** |
|
110 |
* Returns the length of the array. |
|
111 |
* |
|
112 |
* @return the length of the array |
|
113 |
*/ |
|
114 |
public final int length() { |
|
115 |
return array.length; |
|
116 |
} |
|
117 |
||
118 |
/** |
|
119 |
* Gets the current value at position {@code i}. |
|
120 |
* |
|
121 |
* @param i the index |
|
122 |
* @return the current value |
|
123 |
*/ |
|
124 |
public final E get(int i) { |
|
7976
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
125 |
return getRaw(checkedByteOffset(i)); |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
126 |
} |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
127 |
|
11134
9ff7640994bf
7117360: Warnings in java.util.concurrent.atomic package
dl
parents:
9242
diff
changeset
|
128 |
@SuppressWarnings("unchecked") |
7976
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
129 |
private E getRaw(long offset) { |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
130 |
return (E) unsafe.getObjectVolatile(array, offset); |
2 | 131 |
} |
132 |
||
133 |
/** |
|
134 |
* Sets the element at position {@code i} to the given value. |
|
135 |
* |
|
136 |
* @param i the index |
|
137 |
* @param newValue the new value |
|
138 |
*/ |
|
139 |
public final void set(int i, E newValue) { |
|
7976
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
140 |
unsafe.putObjectVolatile(array, checkedByteOffset(i), newValue); |
2 | 141 |
} |
142 |
||
143 |
/** |
|
144 |
* Eventually sets the element at position {@code i} to the given value. |
|
145 |
* |
|
146 |
* @param i the index |
|
147 |
* @param newValue the new value |
|
148 |
* @since 1.6 |
|
149 |
*/ |
|
150 |
public final void lazySet(int i, E newValue) { |
|
7976
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
151 |
unsafe.putOrderedObject(array, checkedByteOffset(i), newValue); |
2 | 152 |
} |
153 |
||
154 |
/** |
|
155 |
* Atomically sets the element at position {@code i} to the given |
|
156 |
* value and returns the old value. |
|
157 |
* |
|
158 |
* @param i the index |
|
159 |
* @param newValue the new value |
|
160 |
* @return the previous value |
|
161 |
*/ |
|
162 |
public final E getAndSet(int i, E newValue) { |
|
7976
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
163 |
long offset = checkedByteOffset(i); |
2 | 164 |
while (true) { |
11892
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
165 |
E current = getRaw(offset); |
7976
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
166 |
if (compareAndSetRaw(offset, current, newValue)) |
2 | 167 |
return current; |
168 |
} |
|
169 |
} |
|
170 |
||
171 |
/** |
|
172 |
* Atomically sets the element at position {@code i} to the given |
|
173 |
* updated value if the current value {@code ==} the expected value. |
|
7976
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
174 |
* |
2 | 175 |
* @param i the index |
176 |
* @param expect the expected value |
|
177 |
* @param update the new value |
|
178 |
* @return true if successful. False return indicates that |
|
179 |
* the actual value was not equal to the expected value. |
|
180 |
*/ |
|
181 |
public final boolean compareAndSet(int i, E expect, E update) { |
|
7976
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
182 |
return compareAndSetRaw(checkedByteOffset(i), expect, update); |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
183 |
} |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
184 |
|
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
185 |
private boolean compareAndSetRaw(long offset, E expect, E update) { |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
186 |
return unsafe.compareAndSwapObject(array, offset, expect, update); |
2 | 187 |
} |
188 |
||
189 |
/** |
|
190 |
* Atomically sets the element at position {@code i} to the given |
|
191 |
* updated value if the current value {@code ==} the expected value. |
|
192 |
* |
|
193 |
* <p>May <a href="package-summary.html#Spurious">fail spuriously</a> |
|
194 |
* and does not provide ordering guarantees, so is only rarely an |
|
195 |
* appropriate alternative to {@code compareAndSet}. |
|
196 |
* |
|
197 |
* @param i the index |
|
198 |
* @param expect the expected value |
|
199 |
* @param update the new value |
|
200 |
* @return true if successful. |
|
201 |
*/ |
|
202 |
public final boolean weakCompareAndSet(int i, E expect, E update) { |
|
203 |
return compareAndSet(i, expect, update); |
|
204 |
} |
|
205 |
||
206 |
/** |
|
207 |
* Returns the String representation of the current values of array. |
|
7976
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
208 |
* @return the String representation of the current values of array |
2 | 209 |
*/ |
210 |
public String toString() { |
|
11892
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
211 |
int iMax = array.length - 1; |
7976
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
212 |
if (iMax == -1) |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
213 |
return "[]"; |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
214 |
|
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
215 |
StringBuilder b = new StringBuilder(); |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
216 |
b.append('['); |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
217 |
for (int i = 0; ; i++) { |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
218 |
b.append(getRaw(byteOffset(i))); |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
219 |
if (i == iMax) |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
220 |
return b.append(']').toString(); |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
221 |
b.append(',').append(' '); |
f273c0d04215
7005424: Resync java.util.concurrent classes with Dougs CVS - Jan 2011
dl
parents:
5506
diff
changeset
|
222 |
} |
2 | 223 |
} |
224 |
||
11892
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
225 |
/** |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
226 |
* Reconstitutes the instance from a stream (that is, deserializes it). |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
227 |
*/ |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
228 |
private void readObject(java.io.ObjectInputStream s) |
14325
622c473a21aa
8001575: Minor/sync/cleanup j.u.c with Dougs CVS - Oct 2012
dl
parents:
11902
diff
changeset
|
229 |
throws java.io.IOException, ClassNotFoundException, |
622c473a21aa
8001575: Minor/sync/cleanup j.u.c with Dougs CVS - Oct 2012
dl
parents:
11902
diff
changeset
|
230 |
java.io.InvalidObjectException { |
11892
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
231 |
// Note: This must be changed if any additional fields are defined |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
232 |
Object a = s.readFields().get("array", null); |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
233 |
if (a == null || !a.getClass().isArray()) |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
234 |
throw new java.io.InvalidObjectException("Not array type"); |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
235 |
if (a.getClass() != Object[].class) |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
236 |
a = Arrays.copyOf((Object[])a, Array.getLength(a), Object[].class); |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
237 |
unsafe.putObjectVolatile(this, arrayFieldOffset, a); |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
238 |
} |
1b260c532b70
7082299: AtomicReferenceArray should ensure that array is Object[]
dl
parents:
9242
diff
changeset
|
239 |
|
2 | 240 |
} |