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Code - Class EDU.oswego.cs.dl.util.concurrent.SynchronizedShort
1 /*
2 File: SynchronizedShort.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 short 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 SynchronizedShort extends SynchronizedVariable implements Comparable, Cloneable {
23
24 protected short value_;
25
26 /**
27 * Make a new SynchronizedShort with the given initial value,
28 * and using its own internal lock.
29 **/
30 public SynchronizedShort(short initialValue) {
31 super();
32 value_ = initialValue;
33 }
34
35 /**
36 * Make a new SynchronizedShort with the given initial value,
37 * and using the supplied lock.
38 **/
39 public SynchronizedShort(short initialValue, Object lock) {
40 super(lock);
41 value_ = initialValue;
42 }
43
44 /**
45 * Return the current value
46 **/
47 public final short get() { synchronized(lock_) { return value_; } }
48
49 /**
50 * Set to newValue.
51 * @return the old value
52 **/
53
54 public short set(short newValue) {
55 synchronized (lock_) {
56 short 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(short assumedValue, short newValue) {
67 synchronized(lock_) {
68 boolean success = (assumedValue == value_);
69 if (success) value_ = newValue;
70 return success;
71 }
72 }
73
74
75 /**
76 * Atomically swap values with another SynchronizedShort.
77 * Uses identityHashCode to avoid deadlock when
78 * two SynchronizedShorts attempt to simultaneously swap with each other.
79 * (Note: Ordering via identyHashCode is not strictly guaranteed
80 * by the language specification to return unique, orderable
81 * values, but in practice JVMs rely on them being unique.)
82 * @return the new value
83 **/
84
85 public short swap(SynchronizedShort other) {
86 if (other == this) return get();
87 SynchronizedShort fst = this;
88 SynchronizedShort snd = other;
89 if (System.identityHashCode(fst) > System.identityHashCode(snd)) {
90 fst = other;
91 snd = this;
92 }
93 synchronized(fst.lock_) {
94 synchronized(snd.lock_) {
95 fst.set(snd.set(fst.get()));
96 return get();
97 }
98 }
99 }
100
101
102 /**
103 * Increment the value.
104 * @return the new value
105 **/
106 public short increment() {
107 synchronized (lock_) {
108 return ++value_;
109 }
110 }
111
112 /**
113 * Decrement the value.
114 * @return the new value
115 **/
116 public short decrement() {
117 synchronized (lock_) {
118 return --value_;
119 }
120 }
121
122 /**
123 * Add amount to value (i.e., set value += amount)
124 * @return the new value
125 **/
126 public short add(short amount) {
127 synchronized (lock_) {
128 return value_ += amount;
129 }
130 }
131
132 /**
133 * Subtract amount from value (i.e., set value -= amount)
134 * @return the new value
135 **/
136 public short subtract(short amount) {
137 synchronized (lock_) {
138 return value_ -= amount;
139 }
140 }
141
142 /**
143 * Multiply value by factor (i.e., set value *= factor)
144 * @return the new value
145 **/
146 public synchronized short multiply(short factor) {
147 synchronized (lock_) {
148 return value_ *= factor;
149 }
150 }
151
152 /**
153 * Divide value by factor (i.e., set value /= factor)
154 * @return the new value
155 **/
156 public short divide(short factor) {
157 synchronized (lock_) {
158 return value_ /= factor;
159 }
160 }
161
162 /**
163 * Set the value to the negative of its old value
164 * @return the new value
165 **/
166 public short negate() {
167 synchronized (lock_) {
168 value_ = (short)(-value_);
169 return value_;
170 }
171 }
172
173 /**
174 * Set the value to its complement
175 * @return the new value
176 **/
177 public short complement() {
178 synchronized (lock_) {
179 value_ = (short)(~value_);
180 return value_;
181 }
182 }
183
184 /**
185 * Set value to value & b.
186 * @return the new value
187 **/
188 public short and(short b) {
189 synchronized (lock_) {
190 value_ = (short)(value_ & b);
191 return value_;
192 }
193 }
194
195 /**
196 * Set value to value | b.
197 * @return the new value
198 **/
199 public short or(short b) {
200 synchronized (lock_) {
201 value_ = (short)(value_ | b);
202 return value_;
203 }
204 }
205
206
207 /**
208 * Set value to value ^ b.
209 * @return the new value
210 **/
211 public short xor(short b) {
212 synchronized (lock_) {
213 value_ = (short)(value_ ^ b);
214 return value_;
215 }
216 }
217
218 public int compareTo(short other) {
219 short val = get();
220 return (val < other)? -1 : (val == other)? 0 : 1;
221 }
222
223 public int compareTo(SynchronizedShort other) {
224 return compareTo(other.get());
225 }
226
227 public int compareTo(Object other) {
228 return compareTo((SynchronizedShort)other);
229 }
230
231 public boolean equals(Object other) {
232 if (other != null &&
233 other instanceof SynchronizedShort)
234 return get() == ((SynchronizedShort)other).get();
235 else
236 return false;
237 }
238
239 public int hashCode() {
240 return (int)(get());
241 }
242
243 public String toString() { return String.valueOf(get()); }
244
245 }
246
247
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