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Java > Open Source Codes > ProducerConsumer


1
2 /*
3  * Copyright © 2002 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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19  * to countries subject to U.S. embargo or to entities identified on U.S.
20  * export exclusion lists, including, but not limited to, the denied persons
21  * and specially designated nationals lists is strictly prohibited.
22  */
23
24
25 public class ProducerConsumer {
26
27   /**
28    * A single producer-consumer instance that is used by others.
29    */
30   public static ProducerConsumer pc = new ProducerConsumer();
31
32   /**
33    * The data structure where the tokens are stored.
34    */
35   private java.util.Vector JavaDoc queue = new java.util.Vector JavaDoc();
36
37   /**
38    * The producer calls this method to add a new token
39    * whenever it is available.
40    */
41   synchronized public void addToken(Token token) {
42     queue.addElement(token);
43     notify();
44   }
45
46   /**
47    * The consumer calls this method to get the next token
48    * in the queue. If the queue is empty, this method
49    * blocks until a token becomes available.
50    */
51   synchronized public Token getToken() {
52     if (queue.size() == 0) {
53       try {
54         wait();
55       } catch (InterruptedException JavaDoc willNotHappen) {
56         throw new Error JavaDoc();
57       }
58     }
59     Token retval = (Token)(queue.elementAt(0));
60     queue.removeElementAt(0);
61     return retval;
62   }
63
64 }
65
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