ReferenceMapTest.java
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.collections4.map;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertNull;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.junit.jupiter.api.Assertions.assertTrue;
import static org.junit.jupiter.api.Assertions.fail;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.function.Consumer;
import org.apache.commons.collections4.map.AbstractHashedMap.HashEntry;
import org.apache.commons.collections4.map.AbstractReferenceMap.ReferenceEntry;
import org.apache.commons.collections4.map.AbstractReferenceMap.ReferenceStrength;
import org.junit.jupiter.api.Test;
/**
* Tests for ReferenceMap.
*
* @param <K> the key type.
* @param <V> the value type.
*/
public class ReferenceMapTest<K, V> extends AbstractIterableMapTest<K, V> {
private static final class AccessibleEntry<K, V> extends ReferenceEntry<K, V> {
final AbstractReferenceMap<K, V> parent;
final Consumer<V> consumer;
AccessibleEntry(final AbstractReferenceMap<K, V> parent, final HashEntry<K, V> next, final int hashCode, final K key, final V value, final Consumer<V> consumer) {
super(parent, next, hashCode, key, value);
this.parent = parent;
this.consumer = consumer;
}
@Override
protected void onPurge() {
if (parent.isValueType(ReferenceStrength.HARD)) {
consumer.accept(getValue());
}
}
}
@SuppressWarnings("unused")
private static void gc() {
try {
// trigger GC
final byte[][] tooLarge = new byte[1000000000][1000000000];
fail("you have too much RAM");
} catch (final OutOfMemoryError ex) {
System.gc(); // ignore
}
}
WeakReference<K> keyReference;
WeakReference<V> valueReference;
// void testCreate() throws Exception {
// resetEmpty();
// writeExternalFormToDisk(
// (java.io.Serializable) map,
// "src/test/resources/data/test/ReferenceMap.emptyCollection.version4.obj");
// resetFull();
// writeExternalFormToDisk(
// (java.io.Serializable) map,
// "src/test/resources/data/test/ReferenceMap.fullCollection.version4.obj");
// }
@SuppressWarnings("unchecked")
public Map<K, V> buildRefMap() {
final K key = (K) new Object();
final V value = (V) new Object();
keyReference = new WeakReference<>(key);
valueReference = new WeakReference<>(value);
final Map<K, V> testMap = new ReferenceMap<>(ReferenceStrength.WEAK, ReferenceStrength.HARD, true);
testMap.put(key, value);
assertEquals(value, testMap.get(key), "In map");
assertNotNull(keyReference.get(), "Weak reference released early (1)");
assertNotNull(valueReference.get(), "Weak reference released early (2)");
return testMap;
}
/*
// Tests often fail because gc is uncontrollable
@Test
void testPurge() {
ReferenceMap map = new ReferenceMap(ReferenceMap.WEAK, ReferenceMap.WEAK);
Object[] hard = new Object[10];
for (int i = 0; i < hard.length; i++) {
hard[i] = new Object();
map.put(hard[i], new Object());
}
gc();
assertTrue("map should be empty after purge of weak values", map.isEmpty());
for (int i = 0; i < hard.length; i++) {
map.put(new Object(), hard[i]);
}
gc();
assertTrue("map should be empty after purge of weak keys", map.isEmpty());
for (int i = 0; i < hard.length; i++) {
map.put(new Object(), hard[i]);
map.put(hard[i], new Object());
}
gc();
assertTrue("map should be empty after purge of weak keys and values", map.isEmpty());
}
@Test
void testGetAfterGC() {
ReferenceMap map = new ReferenceMap(ReferenceMap.WEAK, ReferenceMap.WEAK);
for (int i = 0; i < 10; i++) {
map.put(Integer.valueOf(i), Integer.valueOf(i));
}
gc();
for (int i = 0; i < 10; i++) {
Integer I = Integer.valueOf(i);
assertTrue("map.containsKey should return false for GC'd element", !map.containsKey(I));
assertTrue("map.get should return null for GC'd element", map.get(I) == null);
}
}
@Test
void testEntrySetIteratorAfterGC() {
ReferenceMap map = new ReferenceMap(ReferenceMap.WEAK, ReferenceMap.WEAK);
Object[] hard = new Object[10];
for (int i = 0; i < 10; i++) {
hard[i] = Integer.valueOf(10 + i);
map.put(Integer.valueOf(i), Integer.valueOf(i));
map.put(hard[i], hard[i]);
}
gc();
Iterator iterator = map.entrySet().iterator();
while (iterator.hasNext()) {
Map.Entry entry = (Map.Entry)iterator.next();
Integer key = (Integer)entry.getKey();
Integer value = (Integer)entry.getValue();
assertTrue("iterator should skip GC'd keys", key.intValue() >= 10);
assertTrue("iterator should skip GC'd values", value.intValue() >= 10);
}
}
@Test
void testMapIteratorAfterGC() {
ReferenceMap map = new ReferenceMap(ReferenceMap.WEAK, ReferenceMap.WEAK);
Object[] hard = new Object[10];
for (int i = 0; i < 10; i++) {
hard[i] = Integer.valueOf(10 + i);
map.put(Integer.valueOf(i), Integer.valueOf(i));
map.put(hard[i], hard[i]);
}
gc();
MapIterator iterator = map.mapIterator();
while (iterator.hasNext()) {
Object key1 = iterator.next();
Integer key = (Integer) iterator.getKey();
Integer value = (Integer) iterator.getValue();
assertTrue("iterator keys should match", key == key1);
assertTrue("iterator should skip GC'd keys", key.intValue() >= 10);
assertTrue("iterator should skip GC'd values", value.intValue() >= 10);
}
}
@Test
void testMapIteratorAfterGC2() {
ReferenceMap map = new ReferenceMap(ReferenceMap.WEAK, ReferenceMap.WEAK);
Object[] hard = new Object[10];
for (int i = 0; i < 10; i++) {
hard[i] = Integer.valueOf(10 + i);
map.put(Integer.valueOf(i), Integer.valueOf(i));
map.put(hard[i], hard[i]);
}
MapIterator iterator = map.mapIterator();
while (iterator.hasNext()) {
Object key1 = iterator.next();
gc();
Integer key = (Integer) iterator.getKey();
Integer value = (Integer) iterator.getValue();
assertTrue("iterator keys should match", key == key1);
assertTrue("iterator should skip GC'd keys", key.intValue() >= 10);
assertTrue("iterator should skip GC'd values", value.intValue() >= 10);
}
}
*/
@Override
public String getCompatibilityVersion() {
return "4";
}
@Override
public boolean isAllowNullKey() {
return false;
}
@Override
public boolean isAllowNullValueGet() {
return true;
}
@Override
public boolean isAllowNullValuePut() {
return false;
}
@Override
public ReferenceMap<K, V> makeObject() {
return new ReferenceMap<>(ReferenceStrength.WEAK, ReferenceStrength.WEAK);
}
@Test
void testCustomPurge() {
final List<Integer> expiredValues = new ArrayList<>();
@SuppressWarnings("unchecked")
final Consumer<Integer> consumer = (Consumer<Integer> & Serializable) expiredValues::add;
final Map<Integer, Integer> map = new ReferenceMap<Integer, Integer>(ReferenceStrength.WEAK, ReferenceStrength.HARD, false) {
private static final long serialVersionUID = 1L;
@Override
protected ReferenceEntry<Integer, Integer> createEntry(final HashEntry<Integer, Integer> next, final int hashCode, final Integer key, final Integer value) {
return new AccessibleEntry<>(this, next, hashCode, key, value, consumer);
}
};
for (int i = 100000; i < 100010; i++) {
map.put(Integer.valueOf(i), Integer.valueOf(i));
}
int iterations = 0;
int bytz = 2;
while (true) {
System.gc();
if (iterations++ > 50 || bytz < 0) {
fail("Max iterations reached before resource released.");
}
map.isEmpty();
if (!expiredValues.isEmpty()) {
break;
}
// create garbage:
@SuppressWarnings("unused")
final byte[] b = new byte[bytz];
bytz *= 2;
}
assertFalse(expiredValues.isEmpty(), "Value should be stored");
}
/**
* Test whether after serialization the "data" HashEntry array is the same size as the original.<p>
*
* See <a href="https://issues.apache.org/jira/browse/COLLECTIONS-599">COLLECTIONS-599: HashEntry array object naming data initialized with double the size during deserialization</a>
*/
@Test
void testDataSizeAfterSerialization() throws IOException, ClassNotFoundException {
final ReferenceMap<String, String> serializeMap = new ReferenceMap<>(ReferenceStrength.WEAK, ReferenceStrength.WEAK, true);
serializeMap.put("KEY", "VALUE");
final ByteArrayOutputStream baos = new ByteArrayOutputStream();
try (ObjectOutputStream out = new ObjectOutputStream(baos)) {
out.writeObject(serializeMap);
}
final ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
try (ObjectInputStream in = new ObjectInputStream(bais)) {
@SuppressWarnings("unchecked")
final ReferenceMap<String, String> deserializedMap = (ReferenceMap<String, String>) in.readObject();
assertEquals(1, deserializedMap.size());
assertEquals(serializeMap.data.length, deserializedMap.data.length);
}
}
/**
* Test whether remove is not removing last entry after calling hasNext.
* <p>
* See <a href="https://issues.apache.org/jira/browse/COLLECTIONS-802">COLLECTIONS-802: ReferenceMap iterator remove violates contract</a>
*/
@Test
void testIteratorLastEntryCanBeRemovedAfterHasNext() {
final ReferenceMap<Integer, Integer> map = new ReferenceMap<>();
map.put(1, 2);
final Iterator<Map.Entry<Integer, Integer>> iter = map.entrySet().iterator();
assertTrue(iter.hasNext());
iter.next();
// below line should not affect remove
assertFalse(iter.hasNext());
iter.remove();
assertTrue(map.isEmpty(), "Expect empty but have entry: " + map);
}
@Test
@SuppressWarnings("unchecked")
void testNullHandling() {
resetFull();
assertNull(map.get(null));
assertFalse(map.containsKey(null));
assertFalse(map.containsValue(null));
assertNull(map.remove(null));
assertFalse(map.entrySet().contains(null));
assertFalse(map.containsKey(null));
assertFalse(map.containsValue(null));
assertThrows(NullPointerException.class, () -> map.put(null, null));
assertThrows(NullPointerException.class, () -> map.put((K) new Object(), null));
assertThrows(NullPointerException.class, () -> map.put(null, (V) new Object()));
}
/** Tests whether purge values setting works */
@Test
void testPurgeValues() throws Exception {
// many thanks to Juozas Baliuka for suggesting this method
final Map<K, V> testMap = buildRefMap();
int iterations = 0;
int bytz = 2;
while (true) {
System.gc();
if (iterations++ > 50) {
fail("Max iterations reached before resource released.");
}
testMap.isEmpty();
if (keyReference.get() == null && valueReference.get() == null) {
break;
}
// create garbage:
@SuppressWarnings("unused")
final byte[] b = new byte[bytz];
bytz *= 2;
}
}
}