Mercurial > hg > blitz_condensed
comparison src/EDU/oswego/cs/dl/util/concurrent/SynchronizedInt.java @ 0:3dc0c5604566
Initial checkin of blitz 2.0 fcs - no installer yet.
author | Dan Creswell <dan.creswell@gmail.com> |
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date | Sat, 21 Mar 2009 11:00:06 +0000 |
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-1:000000000000 | 0:3dc0c5604566 |
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1 /* | |
2 File: SynchronizedInt.java | |
3 | |
4 Originally written by Doug Lea and released into the public domain. | |
5 This may be used for any purposes whatsoever without acknowledgment. | |
6 Thanks for the assistance and support of Sun Microsystems Labs, | |
7 and everyone contributing, testing, and using this code. | |
8 | |
9 History: | |
10 Date Who What | |
11 19Jun1998 dl Create public version | |
12 */ | |
13 | |
14 package EDU.oswego.cs.dl.util.concurrent; | |
15 | |
16 /** | |
17 * A class useful for offloading synch for int instance variables. | |
18 * | |
19 * <p>[<a href="http://gee.cs.oswego.edu/dl/classes/EDU/oswego/cs/dl/util/concurrent/intro.html"> Introduction to this package. </a>] | |
20 **/ | |
21 | |
22 public class SynchronizedInt extends SynchronizedVariable implements Comparable, Cloneable { | |
23 | |
24 protected int value_; | |
25 | |
26 /** | |
27 * Make a new SynchronizedInt with the given initial value, | |
28 * and using its own internal lock. | |
29 **/ | |
30 public SynchronizedInt(int initialValue) { | |
31 super(); | |
32 value_ = initialValue; | |
33 } | |
34 | |
35 /** | |
36 * Make a new SynchronizedInt with the given initial value, | |
37 * and using the supplied lock. | |
38 **/ | |
39 public SynchronizedInt(int initialValue, Object lock) { | |
40 super(lock); | |
41 value_ = initialValue; | |
42 } | |
43 | |
44 /** | |
45 * Return the current value | |
46 **/ | |
47 public final int get() { synchronized(lock_) { return value_; } } | |
48 | |
49 /** | |
50 * Set to newValue. | |
51 * @return the old value | |
52 **/ | |
53 | |
54 public int set(int newValue) { | |
55 synchronized (lock_) { | |
56 int old = value_; | |
57 value_ = newValue; | |
58 return old; | |
59 } | |
60 } | |
61 | |
62 /** | |
63 * Set value to newValue only if it is currently assumedValue. | |
64 * @return true if successful | |
65 **/ | |
66 public boolean commit(int assumedValue, int newValue) { | |
67 synchronized(lock_) { | |
68 boolean success = (assumedValue == value_); | |
69 if (success) value_ = newValue; | |
70 return success; | |
71 } | |
72 } | |
73 | |
74 /** | |
75 * Atomically swap values with another SynchronizedInt. | |
76 * Uses identityHashCode to avoid deadlock when | |
77 * two SynchronizedInts attempt to simultaneously swap with each other. | |
78 * (Note: Ordering via identyHashCode is not strictly guaranteed | |
79 * by the language specification to return unique, orderable | |
80 * values, but in practice JVMs rely on them being unique.) | |
81 * @return the new value | |
82 **/ | |
83 | |
84 public int swap(SynchronizedInt other) { | |
85 if (other == this) return get(); | |
86 SynchronizedInt fst = this; | |
87 SynchronizedInt snd = other; | |
88 if (System.identityHashCode(fst) > System.identityHashCode(snd)) { | |
89 fst = other; | |
90 snd = this; | |
91 } | |
92 synchronized(fst.lock_) { | |
93 synchronized(snd.lock_) { | |
94 fst.set(snd.set(fst.get())); | |
95 return get(); | |
96 } | |
97 } | |
98 } | |
99 | |
100 /** | |
101 * Increment the value. | |
102 * @return the new value | |
103 **/ | |
104 public int increment() { | |
105 synchronized (lock_) { | |
106 return ++value_; | |
107 } | |
108 } | |
109 | |
110 /** | |
111 * Decrement the value. | |
112 * @return the new value | |
113 **/ | |
114 public int decrement() { | |
115 synchronized (lock_) { | |
116 return --value_; | |
117 } | |
118 } | |
119 | |
120 /** | |
121 * Add amount to value (i.e., set value += amount) | |
122 * @return the new value | |
123 **/ | |
124 public int add(int amount) { | |
125 synchronized (lock_) { | |
126 return value_ += amount; | |
127 } | |
128 } | |
129 | |
130 /** | |
131 * Subtract amount from value (i.e., set value -= amount) | |
132 * @return the new value | |
133 **/ | |
134 public int subtract(int amount) { | |
135 synchronized (lock_) { | |
136 return value_ -= amount; | |
137 } | |
138 } | |
139 | |
140 /** | |
141 * Multiply value by factor (i.e., set value *= factor) | |
142 * @return the new value | |
143 **/ | |
144 public synchronized int multiply(int factor) { | |
145 synchronized (lock_) { | |
146 return value_ *= factor; | |
147 } | |
148 } | |
149 | |
150 /** | |
151 * Divide value by factor (i.e., set value /= factor) | |
152 * @return the new value | |
153 **/ | |
154 public int divide(int factor) { | |
155 synchronized (lock_) { | |
156 return value_ /= factor; | |
157 } | |
158 } | |
159 | |
160 /** | |
161 * Set the value to the negative of its old value | |
162 * @return the new value | |
163 **/ | |
164 public int negate() { | |
165 synchronized (lock_) { | |
166 value_ = -value_; | |
167 return value_; | |
168 } | |
169 } | |
170 | |
171 /** | |
172 * Set the value to its complement | |
173 * @return the new value | |
174 **/ | |
175 public int complement() { | |
176 synchronized (lock_) { | |
177 value_ = ~value_; | |
178 return value_; | |
179 } | |
180 } | |
181 | |
182 /** | |
183 * Set value to value & b. | |
184 * @return the new value | |
185 **/ | |
186 public int and(int b) { | |
187 synchronized (lock_) { | |
188 value_ = value_ & b; | |
189 return value_; | |
190 } | |
191 } | |
192 | |
193 /** | |
194 * Set value to value | b. | |
195 * @return the new value | |
196 **/ | |
197 public int or(int b) { | |
198 synchronized (lock_) { | |
199 value_ = value_ | b; | |
200 return value_; | |
201 } | |
202 } | |
203 | |
204 | |
205 /** | |
206 * Set value to value ^ b. | |
207 * @return the new value | |
208 **/ | |
209 public int xor(int b) { | |
210 synchronized (lock_) { | |
211 value_ = value_ ^ b; | |
212 return value_; | |
213 } | |
214 } | |
215 | |
216 public int compareTo(int other) { | |
217 int val = get(); | |
218 return (val < other)? -1 : (val == other)? 0 : 1; | |
219 } | |
220 | |
221 public int compareTo(SynchronizedInt other) { | |
222 return compareTo(other.get()); | |
223 } | |
224 | |
225 public int compareTo(Object other) { | |
226 return compareTo((SynchronizedInt)other); | |
227 } | |
228 | |
229 public boolean equals(Object other) { | |
230 if (other != null && | |
231 other instanceof SynchronizedInt) | |
232 return get() == ((SynchronizedInt)other).get(); | |
233 else | |
234 return false; | |
235 } | |
236 | |
237 public int hashCode() { return get(); } | |
238 | |
239 public String toString() { return String.valueOf(get()); } | |
240 | |
241 } | |
242 |