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1
46 package net.jforum.util.concurrent.queue;
47
48 import java.security.InvalidParameterException  ;
49 import java.util.LinkedList ;
50
51 import net.jforum.util.concurrent.Queue;
52
53
56 public class UnboundedFifoQueue implements Queue
57 {
58 private final LinkedList queue = new LinkedList ();
59
60 public UnboundedFifoQueue() { }
61
62 public Object get() throws InterruptedException
63 {
64 if(Thread.interrupted()) {
65 throw new InterruptedException ();
66 }
67
68 synchronized(queue) {
69 try {
70 while(queue.isEmpty()) {
71 queue.wait();
72 }
73
74 return queue.removeFirst();
75 }
76 catch(InterruptedException e) {
77 queue.notify();
78 throw e;
79 }
80 }
81 }
82
83 public Object pool(final long timeout) throws InterruptedException
84 {
85 if(Thread.interrupted()) {
86 throw new InterruptedException ();
87 }
88
89 synchronized(queue) {
90 if(!queue.isEmpty()) {
91 return queue.removeFirst();
92 }
93
94 if(timeout <= 0) {
95 return null;
96 }
97
98 try {
99 long remaining = timeout;
100 long start = System.currentTimeMillis();
101
102 for(;;) {
103 queue.wait(remaining);
104
105 if(!queue.isEmpty()) {
106 return queue.removeFirst();
107 }
108
109 remaining = timeout - (System.currentTimeMillis() - start);
110
111 if(remaining <= 0) {
112 return null;
113 }
114 }
115 }
116 catch(InterruptedException e) {
117 queue.notify();
118 throw e;
119 }
120 }
121 }
122
123 public void put(Object obj) throws InterruptedException
124 {
125 offer(obj, 0);
126 }
127
128 public boolean offer(Object obj, long timeout) throws InterruptedException
129 {
130 if(obj == null) {
131 throw new InvalidParameterException ("obj is null");
132 }
133
134 if(Thread.interrupted()) {
135 throw new InterruptedException ();
136 }
137
138 synchronized(queue) {
139 queue.add(obj);
140 queue.notify();
141 }
142 return true;
143 }
144
145 public int size()
146 {
147 synchronized(queue) {
148 return queue.size();
149 }
150 }
151 }
152 |
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