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1 package com.daffodilwoods.daffodildb.server.datasystem.persistentsystem;
2
3 import java.util.HashMap  ;
4 import java.util.Iterator ;
5 import java.util.Set ;
6 import java.util.Map ;
7
8
16
17 public class ClusterLock {
18 HashMap map = new HashMap ();
19 public ClusterLock() {
20 }
21
22 public void lock(int clusterAddress) {
23
24 Integer integer = new Integer (clusterAddress);
25 LockCounter lockObject = getLockCounter(integer);
26
27 while(true){
28 synchronized (lockObject) {
29
30 if (lockObject.getOwner() == null) {
31 lockObject.setOwner(Thread.currentThread());
32 return;
33 }
34 }
35 Object w = new Object ();
36
37 synchronized(w){ try {
39 lockObject.waiters.add(w);
40 long startTime = System.currentTimeMillis() ;
41 w.wait(5000);
42 if((System.currentTimeMillis() - startTime) >= 5000 )
43 lockObject.waiters.remove(w) ;
44 }
45
46 catch (InterruptedException ex) {
47 }
48 }
49 }
50 }
51
52 public void unLock(int clusterAddress) {
53 synchronized (map) {
54 LockCounter lc = (LockCounter)map.get(new Integer (clusterAddress));
55 synchronized(lc){
56 lc.decreaseCount();
57 if(lc.waiters.size()>0) {
58 Object w = lc.waiters.get(0);
59 synchronized(w){
60 w.notify();
61 lc.waiters.remove(w);
62 }
63 }else{
64 if(lc.getCount()==0){
65 map.remove(new Integer (clusterAddress));
66 }
67 }
68 lc.setOwner(null);
69 }
70 }
71 }
72
73 private LockCounter getLockCounter( Integer integer){
74 synchronized(map){
75 LockCounter lc = (LockCounter)map.get(integer);
76 if(lc==null){
77 lc = new LockCounter();
78 map.put(integer, lc);
79 }
80 lc.inreaseCount();
81 return lc;
82 }
83 }
84 }
85 |
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