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1
5 package com.tc.util;
6
7 import com.tc.logging.TCLogger;
8 import com.tc.logging.TCLogging;
9
10 import java.util.Collection  ;
11 import java.util.HashMap ;
12 import java.util.Map ;
13 import java.util.SortedSet ;
14 import java.util.TreeSet ;
15
16 public class SequenceValidator {
17
18 private static final TCLogger logger = TCLogging.getLogger(SequenceValidator.class);
19
20 private final Map sequences = new HashMap ();
21 private final long start;
22
23 public SequenceValidator(long start) {
24 this.start = start;
25 }
26
27 public synchronized boolean isNext(Object key, SequenceID candidate) {
29 if (candidate.isNull()) return true;
30 Sequencer sequencer = getOrCreate(key);
31 return sequencer.isNext(candidate);
32 }
33
34 public synchronized void setCurrent(Object key, SequenceID next) throws InvalidSequenceIDException {
35 if (key == null || SequenceID.NULL_ID.equals(next)) return;
36 Sequencer s = getOrCreate(key);
37 s.setCurrent(next);
38 }
39
40 public synchronized SequenceID getCurrent(Object key) {
42 Sequencer s = (Sequencer) sequences.get(key);
43 Assert.assertNotNull(s);
44 return s.getCurrent();
45
46 }
47
48 public synchronized void initSequence(Object key, Collection sequenceIDs) {
49 Assert.assertFalse(sequences.containsKey(key));
50 sequences.put(key, new Sequencer(key, start, sequenceIDs));
51 }
52
53 public synchronized void remove(Object key) {
54 sequences.remove(key);
55 }
56
57 public synchronized int size() {
58 return sequences.size();
59 }
60
61 private Sequencer getOrCreate(Object key) {
62 Sequencer sequencer = (Sequencer) sequences.get(key);
63 if (sequencer == null) {
64 sequencer = new Sequencer(key, start);
65 sequences.put(key, sequencer);
66 }
67 return sequencer;
68 }
69
70 private static class Sequencer {
71
72 SortedSet sequenceIDs;
73 SequenceID current;
74
75 Sequencer(Object key, long start, Collection sequenceIDs) {
76 if (sequenceIDs.size() > 0) {
77 this.sequenceIDs = new TreeSet (SequenceID.COMPARATOR);
78 this.sequenceIDs.addAll(sequenceIDs);
79 current = new SequenceID(start);
80 } else {
81 throw new AssertionError ("Sequencer should be set to a valid SequenceID Sequence !!!");
82 }
83 logger.info("Setting initial Sequence IDs for " + key + " current = " + current + " next = " + this.sequenceIDs);
84 }
85
86 Sequencer(Object key, long start) {
87 current = new SequenceID(start);
88 logger.debug("Setting initial Sequence IDs for " + key + " current = " + current);
89 }
90
91 public boolean isNext(SequenceID candidate) {
92 if (candidate.toLong() <= current.toLong()) {
93 logger.warn("Sequence IDs = " + sequenceIDs + " current = " + current + " but candidate = " + candidate);
94 return false;
95 }
96 if (sequenceIDs == null) {
97 return current.toLong() + 1 == candidate.toLong();
98 } else {
99 return (((SequenceID) sequenceIDs.first()).toLong() == candidate.toLong());
100 }
101 }
102
103 public void setCurrent(SequenceID next) throws InvalidSequenceIDException {
104 if (!isNext(next)) { throw new InvalidSequenceIDException("Trying to set to " + next + " but current = "
105 + current); }
106 if (sequenceIDs != null) {
107 logger.info("Setting current Sequence IDs from current = " + current + " to next = " + next);
108 sequenceIDs.headSet(next.next()).clear();
109 if (sequenceIDs.size() == 0) {
110 sequenceIDs = null;
111 }
112 }
113 current = next;
114 }
115
116 public SequenceID getCurrent() {
117 return current;
118 }
119 }
120 }
121 |
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