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1
3 package org.jmock.examples.timedcache;
4
5 import java.util.HashMap  ;
6
7
8 public class TimedCache
9 {
10 private ObjectLoader loader;
11 private Clock clock;
12 private ReloadPolicy reloadPolicy;
13 private HashMap cachedValues = new HashMap ();
14
15 private class TimestampedValue
16 {
17 public final Object value;
18 public final Timestamp loadTime;
19
20 public TimestampedValue( final Object value, final Timestamp timestamp ) {
21 this.value = value;
22 this.loadTime = timestamp;
23 }
24 }
25
26
27 public TimedCache( ObjectLoader loader, Clock clock, ReloadPolicy reloadPolicy ) {
28 this.loader = loader;
29 this.clock = clock;
30 this.reloadPolicy = reloadPolicy;
31 }
32
33 public Object lookup( Object theKey ) {
34 TimestampedValue found = (TimestampedValue)cachedValues.get(theKey);
35
36 if (found == null || reloadPolicy.shouldReload(found.loadTime, clock.getCurrentTime())) {
37 found = loadObject(theKey);
38 }
39 return found.value;
40 }
41
42 private TimestampedValue loadObject( Object key ) {
43 Object value = loader.load(key);
44 TimestampedValue timestampedValue = new TimestampedValue(value, clock.getCurrentTime());
45
46 cachedValues.put(key, timestampedValue);
47
48 return timestampedValue;
49 }
50
51 public void putValue( Object key, Object value, Timestamp loadTime ) {
52 cachedValues.put(key, new TimestampedValue(value, loadTime));
53
54 }
55 } |
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