|
1
24 package org.objectweb.jalisto.se.impl.lock;
25
26 import org.objectweb.jalisto.se.exception.multi.LockException;
27
28 import java.io.Serializable  ;
29 import java.util.ArrayList ;
30 import java.util.HashMap ;
31 import java.util.Map ;
32
33 public class DeadLockToken implements Serializable {
34
35 public DeadLockToken(Object tokenId) {
36 this.tokenId = tokenId;
37 nexts = new ArrayList ();
38 tokens.put(tokenId, this);
39 }
40
41 public static DeadLockToken getToken(Object tokenId) {
42 return (DeadLockToken) tokens.get(tokenId);
43 }
44
45
48 public static Map getTokens() {
49 return tokens;
50 }
51
52 public boolean isWaitingFor(DeadLockToken token) {
53 return nexts.contains(token);
54 }
55
56 public boolean couldWakeUp() {
57 return nexts.isEmpty();
58 }
59
60 public synchronized void noMoreWaitFor(DeadLockToken releasingSessionToken) {
61 nexts.remove(releasingSessionToken);
62 }
63
64 public synchronized void timeOutWakeUp(DeadLockToken tokenWhoWaitForThisOne) {
65 if (tokenWhoWaitForThisOne != null) {
66 tokenWhoWaitForThisOne.noMoreWaitFor(this);
67 for (int i = 0; i < nexts.size(); i++) {
68 tokenWhoWaitForThisOne.waitFor((DeadLockToken) nexts.get(i));
69 }
70 }
71 nexts.clear();
72 }
73
74 public String toString() {
75 if (nexts.isEmpty()) {
76 return "DLT " + tokenId + " waiting for nobody";
77 }
78 StringBuffer result = new StringBuffer ();
79 result.append("DLT ").append(tokenId).append(" waiting for {");
80 for (int i = 0; i < nexts.size(); i++) {
81 result.append(((DeadLockToken) nexts.get(i)).tokenId);
82 if (i != (nexts.size() - 1)) {
83 result.append(", ");
84 }
85 }
86 result.append('}');
87 return result.toString();
88 }
89
90 public synchronized void waitFor(DeadLockToken tokenToWaitFor) {
91 tokenToWaitFor.detectDeadLock(this);
92 nexts.add(tokenToWaitFor);
93 }
94
95 private void detectDeadLock(DeadLockToken candidate) {
96 if (this.equals(candidate)) {
97 throw new LockException("dead lock : candidate " + candidate + " with " + tokens.toString());
98 }
99 if (!nexts.isEmpty()) {
100 for (int i = 0; i < nexts.size(); i++) {
101 ((DeadLockToken) nexts.get(i)).detectDeadLock(candidate);
102 }
103 }
104 }
105
106 private static Map tokens = new HashMap ();
107 private ArrayList nexts;
108 private Object tokenId;
109
110 static final long serialVersionUID = -7589377087964761459L;
111 }
112 |
Popular Tags |
Java API By Example, From Geeks To Geeks.