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1
4 package com.tc.stats.counter.sampled;
5
6 import com.tc.stats.LossyStack;
7 import com.tc.stats.counter.CounterImpl;
8
9 import java.math.BigDecimal  ;
10 import java.math.BigInteger ;
11 import java.util.TimerTask ;
12
13
16 public class SampledCounterImpl extends CounterImpl implements SampledCounter {
17 private final LossyStack history;
18 private final boolean resetOnSample;
19 private final TimerTask samplerTask;
20 private TimeStampedCounterValue min;
21 private TimeStampedCounterValue max;
22 private Double average = null;
23
24 public SampledCounterImpl(SampledCounterConfig config) {
25 super(config.getInitialValue());
26
27 this.history = new LossyStack(config.getHistorySize());
28 this.resetOnSample = config.isResetOnSample();
29
30 this.samplerTask = new TimerTask () {
31 public void run() {
32 recordSample();
33 }
34 };
35
36 recordSample();
37 }
38
39 public TimeStampedCounterValue getMostRecentSample() {
40 return (TimeStampedCounterValue) this.history.peek();
41 }
42
43 public TimeStampedCounterValue[] getAllSampleValues() {
44 return (TimeStampedCounterValue[]) this.history.toArray(new TimeStampedCounterValue[this.history.depth()]);
45 }
46
47 public void shutdown() {
48 if (samplerTask != null) {
49 samplerTask.cancel();
50 }
51 }
52
53 TimerTask getTimerTask() {
54 return this.samplerTask;
55 }
56
57 synchronized void recordSample() {
58 final long sample;
59 if (resetOnSample) {
60 sample = getAndSet(0L);
61 } else {
62 sample = getValue();
63 }
64
65 final long now = System.currentTimeMillis();
66 TimeStampedCounterValue timedSample = new TimeStampedCounterValue(now, sample);
67
68 if ((min == null) || (sample < min.getCounterValue())) {
69 min = timedSample;
70 }
71
72 if ((max == null) || (sample > max.getCounterValue())) {
73 max = timedSample;
74 }
75
76 average = null; history.push(timedSample);
78 }
79
80 public synchronized TimeStampedCounterValue getMin() {
81 return this.min;
82 }
83
84 public synchronized TimeStampedCounterValue getMax() {
85 return this.max;
86 }
87
88 public synchronized double getAverage() {
89 if (average == null) {
90 average = new Double (computeAverage());
91 }
92 return this.average.doubleValue();
93 }
94
95 private double computeAverage() {
96 TimeStampedCounterValue[] all = getAllSampleValues();
97
98 if (all.length == 0) { return 0D; }
99
100 BigInteger total = BigInteger.ZERO;
101 for (int i = 0, n = all.length; i < n; i++) {
102 final long sample = all[i].getCounterValue();
103 total = total.add(new BigInteger (String.valueOf(sample)));
104 }
105
106 return new BigDecimal (total).divide(new BigDecimal (all.length), BigDecimal.ROUND_HALF_UP).doubleValue();
107 }
108 }
109 |
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