1 package org.apache.commons.classscan.util;
2
3 import static org.junit.Assert.assertEquals;
4 import static org.junit.Assert.assertFalse;
5 import static org.junit.Assert.assertNotNull;
6 import static org.junit.Assert.assertNull;
7 import static org.junit.Assert.assertSame;
8 import static org.junit.Assert.assertTrue;
9
10 import java.lang.ref.Reference;
11 import java.lang.ref.ReferenceQueue;
12 import java.lang.ref.WeakReference;
13 import java.util.ArrayList;
14 import java.util.List;
15
16 import org.junit.Test;
17
18 public class ReapingHashMapTest {
19
20 @Test
21 public void testHashWeakReferenceIsCollected() throws InterruptedException {
22 ReferenceQueue<BigObject> queue = new ReferenceQueue<BigObject>();
23 ReapingHashMap.HashWeakReference<BigObject> hwr = new ReapingHashMap.HashWeakReference<BigObject>(new BigObject(2), queue);
24 assertNotNull(hwr.get());
25 forceWeakRefCollection(queue, hwr);
26 }
27
28 @Test
29 public void testNullReferenceIsNotCollected() throws InterruptedException {
30 ReferenceQueue<BigObject> queue = new ReferenceQueue<BigObject>();
31
32 ReapingHashMap.HashWeakReference<BigObject> nullRef = new ReapingHashMap.HashWeakReference<BigObject>(null, queue);
33 assertNull(nullRef.get());
34
35 ReapingHashMap.HashWeakReference<BigObject> nnRef = new ReapingHashMap.HashWeakReference<BigObject>(new BigObject(2), queue);
36 forceWeakRefCollection(queue, nnRef);
37
38 assertFalse(nullRef.isEnqueued());
39 assertNull(queue.poll());
40 }
41
42 @Test(timeout=10000)
43 public void testReapingHashMapIsCollected() throws InterruptedException {
44 ReapingHashMap<BigObject, Integer> rhm = new ReapingHashMap<BigObject, Integer>();
45 WeakReference<BigObject> key = notReaped(rhm);
46 do {
47 testHashWeakReferenceIsCollected();
48 }
49 while(key.get()!=null);
50 }
51
52 public WeakReference<BigObject> notReaped(ReapingHashMap<BigObject, Integer> rhm) {
53 BigObject key = new BigObject(2);
54 Integer value = new Integer(2);
55
56 assertNull(rhm.get(null));
57 assertNull(rhm.get(key));
58
59 rhm.put(key, value);
60 assertEquals(value, rhm.get(key));
61
62 Integer nullValue = new Integer(0);
63 rhm.put(null, nullValue);
64 assertEquals(nullValue, rhm.get(null));
65
66 return new WeakReference<BigObject>(key);
67 }
68
69 static class BigObject {
70 byte[][] lotsOfMemory;
71
72 BigObject(int max) {
73 byte[][] holder= new byte[max][];
74 int power= 1;
75 for(int i= 0; i<holder.length; ++i) {
76 byte[] bytes= new byte[power];
77 holder[i]= bytes;
78 power*= 2;
79 }
80 }
81 };
82
83 public <T> void forceWeakRefCollection(ReferenceQueue<T> queue, WeakReference<T> ref) throws InterruptedException {
84
85 List<BigObject> list = new ArrayList<BigObject>();
86 for (int i = 0; true; i++) {
87 try {
88 BigObject holder = new BigObject(i);
89 list.add(holder);
90 } catch (OutOfMemoryError oome) {
91 i = 0;
92 }
93
94 if(ref.isEnqueued()) {
95 assertTrue(ref.isEnqueued());
96 Reference<? extends T> pollRef = queue.remove(1000);
97 assertSame(pollRef, ref);
98 assertEquals(pollRef, ref);
99 assertFalse(ref.isEnqueued());
100 assertNull(ref.get());
101 return;
102 }
103 }
104 }
105 }