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1
3 package org.jgroups.protocols.ring;
4
5 import org.jgroups.Address;
6 import org.jgroups.Event;
7 import org.jgroups.Message;
8 import org.jgroups.protocols.TOTAL_TOKEN;
9 import org.jgroups.stack.IpAddress;
10 import org.jgroups.stack.RpcProtocol;
11
12 import java.io.Serializable  ;
13 import java.util.Vector ;
14
15
16 public class UdpRingNode implements RingNode
17 {
18
19 final Address thisNode;
20 Address nextNode;
21 final RpcProtocol rpcProtocol;
22 Object token;
23 final Object mutex = new Object ();
24 final TOTAL_TOKEN.RingTokenHeader tokenHeader;
25 boolean tokenInStack = false;
26
27
28 public UdpRingNode(RpcProtocol owner, Address memberAddress)
29 {
30 rpcProtocol = owner;
31 thisNode = memberAddress;
32 nextNode = null;
33 tokenHeader = new TOTAL_TOKEN.RingTokenHeader();
34 }
35
36 public IpAddress getTokenReceiverAddress()
37 {
38 return (IpAddress) thisNode;
39 }
40
41 public synchronized void tokenArrived(Object token)
42 {
43 tokenInStack = true;
44 this.token = token;
45 this.notifyAll();
46 }
47
48 public Object receiveToken(int timeout) throws TokenLostException
49 {
50 Address wasNext = nextNode;
51
52 try
53 {
54
55 synchronized (this)
56 {
57 while (!tokenInStack)
58 {
59 wait(timeout);
60 break;
61 }
62
63 if (!tokenInStack)
65 {
66 throw new TokenLostException("Token wait timout expired", null,
67 wasNext, TokenLostException.WHILE_RECEIVING);
68 }
69 }
70 }
71 catch (InterruptedException ie)
72 {
73 throw new TokenLostException("Token thread interrupted", ie,
74 wasNext, TokenLostException.WHILE_RECEIVING);
75 }
76 return token;
77 }
78
79 public Object receiveToken() throws TokenLostException
80 {
81 return receiveToken(0);
82 }
83
84 public synchronized void passToken(Object token)
85 {
86 Message t = new Message(nextNode, thisNode, (Serializable ) token);
87 t.putHeader(TOTAL_TOKEN.prot_name, tokenHeader);
88 rpcProtocol.passDown(new Event(Event.MSG, t));
89 tokenInStack = false;
90 }
91
92
93 public synchronized void reconfigure(Vector newMembers)
94 {
95 if (isNextNeighbourChanged(newMembers))
96 {
97 nextNode = getNextNode(newMembers);
98 }
99 }
100
101 private boolean isNextNeighbourChanged(Vector newMembers)
102 {
103 Address oldNeighbour = nextNode;
104 Address newNeighbour = getNextNode(newMembers);
105 return !(newNeighbour.equals(oldNeighbour));
106 }
107
108 private Address getNextNode(Vector otherNodes)
109 {
110 int myIndex = otherNodes.indexOf(thisNode);
111 return (myIndex == otherNodes.size() - 1)?
112 (Address) otherNodes.firstElement():
113 (Address) otherNodes.elementAt(myIndex + 1);
114
115 }
116 }
117 |
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