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8078645: removeIf(filter) in ConcurrentHashMap removes entries for which filter is false

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Co-authored-by: Doug Lea <dl@cs.oswego.edu>
Reviewed-by: martin, dholmes
This commit is contained in:
Paul Sandoz 2015-05-12 10:50:40 +02:00
parent 7ceb605aa6
commit 0e7987c721
4 changed files with 363 additions and 67 deletions
jdk
src/java.base/share/classes/java/util/concurrent
ConcurrentHashMap.javaConcurrentMap.javaConcurrentSkipListMap.java
test/java/util/concurrent/ConcurrentMap
ConcurrentRemoveIf.java

48
jdk/src/java.base/share/classes/java/util/concurrent/ConcurrentHashMap.java

@ -64,6 +64,7 @@ import java.util.function.DoubleBinaryOperator;
import java.util.function.Function;
import java.util.function.IntBinaryOperator;
import java.util.function.LongBinaryOperator;
import java.util.function.Predicate;
import java.util.function.ToDoubleBiFunction;
import java.util.function.ToDoubleFunction;
import java.util.function.ToIntBiFunction;
@ -1618,6 +1619,45 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
}
}
/**
* Helper method for EntrySet.removeIf
*/
boolean removeEntryIf(Predicate<? super Entry<K, V>> function) {
if (function == null) throw new NullPointerException();
Node<K,V>[] t;
boolean removed = false;
if ((t = table) != null) {
Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
for (Node<K,V> p; (p = it.advance()) != null; ) {
K k = p.key;
V v = p.val;
Map.Entry<K,V> e = new AbstractMap.SimpleImmutableEntry<>(k, v);
if (function.test(e) && replaceNode(k, null, v) != null)
removed = true;
}
}
return removed;
}
/**
* Helper method for Values.removeIf
*/
boolean removeValueIf(Predicate<? super V> function) {
if (function == null) throw new NullPointerException();
Node<K,V>[] t;
boolean removed = false;
if ((t = table) != null) {
Traverser<K,V> it = new Traverser<K,V>(t, t.length, 0, t.length);
for (Node<K,V> p; (p = it.advance()) != null; ) {
K k = p.key;
V v = p.val;
if (function.test(v) && replaceNode(k, null, v) != null)
removed = true;
}
}
return removed;
}
/**
* If the specified key is not already associated with a value,
* attempts to compute its value using the given mapping function
@ -4690,6 +4730,10 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
throw new UnsupportedOperationException();
}
public boolean removeIf(Predicate<? super V> filter) {
return map.removeValueIf(filter);
}
public Spliterator<V> spliterator() {
Node<K,V>[] t;
ConcurrentHashMap<K,V> m = map;
@ -4759,6 +4803,10 @@ public class ConcurrentHashMap<K,V> extends AbstractMap<K,V>
return added;
}
public boolean removeIf(Predicate<? super Entry<K, V>> filter) {
return map.removeEntryIf(filter);
}
public final int hashCode() {
int h = 0;
Node<K,V>[] t;

140
jdk/src/java.base/share/classes/java/util/concurrent/ConcurrentMap.java

@ -34,6 +34,7 @@
*/
package java.util.concurrent;
import java.util.Map;
import java.util.Objects;
import java.util.function.BiConsumer;
@ -44,6 +45,14 @@ import java.util.function.Function;
* A {@link java.util.Map} providing thread safety and atomicity
* guarantees.
*
* <p>To maintain the specified guarantees, default implementations of
* methods including {@link #putIfAbsent} inherited from {@link Map}
* must be overridden by implementations of this interface. Similarly,
* implementations of the collections returned by methods {@link
* #keySet}, {@link #values}, and {@link #entrySet} must override
* methods such as {@code removeIf} when necessary to
* preserve atomicity guarantees.
*
* <p>Memory consistency effects: As with other concurrent
* collections, actions in a thread prior to placing an object into a
* {@code ConcurrentMap} as a key or value
@ -60,7 +69,7 @@ import java.util.function.Function;
* @param <K> the type of keys maintained by this map
* @param <V> the type of mapped values
*/
public interface ConcurrentMap<K, V> extends Map<K, V> {
public interface ConcurrentMap<K,V> extends Map<K,V> {
/**
* {@inheritDoc}
@ -86,9 +95,9 @@ public interface ConcurrentMap<K, V> extends Map<K, V> {
* @implSpec The default implementation is equivalent to, for this
* {@code map}:
* <pre> {@code
* for ((Map.Entry<K, V> entry : map.entrySet())
* action.accept(entry.getKey(), entry.getValue());
* }</pre>
* for (Map.Entry<K,V> entry : map.entrySet()) {
* action.accept(entry.getKey(), entry.getValue());
* }}</pre>
*
* @implNote The default implementation assumes that
* {@code IllegalStateException} thrown by {@code getKey()} or
@ -101,13 +110,13 @@ public interface ConcurrentMap<K, V> extends Map<K, V> {
@Override
default void forEach(BiConsumer<? super K, ? super V> action) {
Objects.requireNonNull(action);
for (Map.Entry<K, V> entry : entrySet()) {
for (Map.Entry<K,V> entry : entrySet()) {
K k;
V v;
try {
k = entry.getKey();
v = entry.getValue();
} catch(IllegalStateException ise) {
} catch (IllegalStateException ise) {
// this usually means the entry is no longer in the map.
continue;
}
@ -117,14 +126,13 @@ public interface ConcurrentMap<K, V> extends Map<K, V> {
/**
* If the specified key is not already associated
* with a value, associate it with the given value.
* This is equivalent to
* <pre> {@code
* with a value, associates it with the given value.
* This is equivalent to, for this {@code map}:
* <pre> {@code
* if (!map.containsKey(key))
* return map.put(key, value);
* else
* return map.get(key);
* }</pre>
* return map.get(key);}</pre>
*
* except that the action is performed atomically.
*
@ -147,18 +155,19 @@ public interface ConcurrentMap<K, V> extends Map<K, V> {
* @throws IllegalArgumentException if some property of the specified key
* or value prevents it from being stored in this map
*/
V putIfAbsent(K key, V value);
V putIfAbsent(K key, V value);
/**
* Removes the entry for a key only if currently mapped to a given value.
* This is equivalent to
* <pre> {@code
* if (map.containsKey(key) && Objects.equals(map.get(key), value)) {
* This is equivalent to, for this {@code map}:
* <pre> {@code
* if (map.containsKey(key)
* && Objects.equals(map.get(key), value)) {
* map.remove(key);
* return true;
* } else
* } else {
* return false;
* }</pre>
* }}</pre>
*
* except that the action is performed atomically.
*
@ -181,14 +190,15 @@ public interface ConcurrentMap<K, V> extends Map<K, V> {
/**
* Replaces the entry for a key only if currently mapped to a given value.
* This is equivalent to
* <pre> {@code
* if (map.containsKey(key) && Objects.equals(map.get(key), oldValue)) {
* This is equivalent to, for this {@code map}:
* <pre> {@code
* if (map.containsKey(key)
* && Objects.equals(map.get(key), oldValue)) {
* map.put(key, newValue);
* return true;
* } else
* } else {
* return false;
* }</pre>
* }}</pre>
*
* except that the action is performed atomically.
*
@ -212,13 +222,12 @@ public interface ConcurrentMap<K, V> extends Map<K, V> {
/**
* Replaces the entry for a key only if currently mapped to some value.
* This is equivalent to
* <pre> {@code
* if (map.containsKey(key)) {
* This is equivalent to, for this {@code map}:
* <pre> {@code
* if (map.containsKey(key))
* return map.put(key, value);
* } else
* return null;
* }</pre>
* else
* return null;}</pre>
*
* except that the action is performed atomically.
*
@ -249,12 +258,14 @@ public interface ConcurrentMap<K, V> extends Map<K, V> {
* @implSpec
* <p>The default implementation is equivalent to, for this {@code map}:
* <pre> {@code
* for ((Map.Entry<K, V> entry : map.entrySet())
* do {
* K k = entry.getKey();
* V v = entry.getValue();
* } while(!replace(k, v, function.apply(k, v)));
* }</pre>
* for (Map.Entry<K,V> entry : map.entrySet()) {
* K k;
* V v;
* do {
* k = entry.getKey();
* v = entry.getValue();
* } while (!map.replace(k, v, function.apply(k, v)));
* }}</pre>
*
* The default implementation may retry these steps when multiple
* threads attempt updates including potentially calling the function
@ -275,7 +286,7 @@ public interface ConcurrentMap<K, V> extends Map<K, V> {
default void replaceAll(BiFunction<? super K, ? super V, ? extends V> function) {
Objects.requireNonNull(function);
forEach((k,v) -> {
while(!replace(k, v, function.apply(k, v))) {
while (!replace(k, v, function.apply(k, v))) {
// v changed or k is gone
if ( (v = get(k)) == null) {
// k is no longer in the map.
@ -295,11 +306,10 @@ public interface ConcurrentMap<K, V> extends Map<K, V> {
*
* <pre> {@code
* if (map.get(key) == null) {
* V newValue = mappingFunction.apply(key);
* if (newValue != null)
* return map.putIfAbsent(key, newValue);
* }
* }</pre>
* V newValue = mappingFunction.apply(key);
* if (newValue != null)
* return map.putIfAbsent(key, newValue);
* }}</pre>
*
* The default implementation may retry these steps when multiple
* threads attempt updates including potentially calling the mapping
@ -331,18 +341,17 @@ public interface ConcurrentMap<K, V> extends Map<K, V> {
* @implSpec
* The default implementation is equivalent to performing the following
* steps for this {@code map}, then returning the current value or
* {@code null} if now absent. :
* {@code null} if now absent:
*
* <pre> {@code
* if (map.get(key) != null) {
* V oldValue = map.get(key);
* V newValue = remappingFunction.apply(key, oldValue);
* if (newValue != null)
* map.replace(key, oldValue, newValue);
* else
* map.remove(key, oldValue);
* }
* }</pre>
* V oldValue = map.get(key);
* V newValue = remappingFunction.apply(key, oldValue);
* if (newValue != null)
* map.replace(key, oldValue, newValue);
* else
* map.remove(key, oldValue);
* }}</pre>
*
* The default implementation may retry these steps when multiple threads
* attempt updates including potentially calling the remapping function
@ -363,13 +372,13 @@ public interface ConcurrentMap<K, V> extends Map<K, V> {
BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
Objects.requireNonNull(remappingFunction);
V oldValue;
while((oldValue = get(key)) != null) {
while ((oldValue = get(key)) != null) {
V newValue = remappingFunction.apply(key, oldValue);
if (newValue != null) {
if (replace(key, oldValue, newValue))
return newValue;
} else if (remove(key, oldValue))
return null;
return null;
}
return oldValue;
}
@ -386,17 +395,16 @@ public interface ConcurrentMap<K, V> extends Map<K, V> {
* V oldValue = map.get(key);
* V newValue = remappingFunction.apply(key, oldValue);
* if (oldValue != null ) {
* if (newValue != null)
* map.replace(key, oldValue, newValue);
* else
* map.remove(key, oldValue);
* if (newValue != null)
* map.replace(key, oldValue, newValue);
* else
* map.remove(key, oldValue);
* } else {
* if (newValue != null)
* map.putIfAbsent(key, newValue);
* else
* return null;
* }
* }</pre>
* if (newValue != null)
* map.putIfAbsent(key, newValue);
* else
* return null;
* }}</pre>
*
* The default implementation may retry these steps when multiple
* threads attempt updates including potentially calling the remapping
@ -417,7 +425,7 @@ public interface ConcurrentMap<K, V> extends Map<K, V> {
BiFunction<? super K, ? super V, ? extends V> remappingFunction) {
Objects.requireNonNull(remappingFunction);
V oldValue = get(key);
for(;;) {
for (;;) {
V newValue = remappingFunction.apply(key, oldValue);
if (newValue == null) {
// delete mapping
@ -458,7 +466,6 @@ public interface ConcurrentMap<K, V> extends Map<K, V> {
}
}
/**
* {@inheritDoc}
*
@ -470,12 +477,11 @@ public interface ConcurrentMap<K, V> extends Map<K, V> {
* <pre> {@code
* V oldValue = map.get(key);
* V newValue = (oldValue == null) ? value :
* remappingFunction.apply(oldValue, value);
* remappingFunction.apply(oldValue, value);
* if (newValue == null)
* map.remove(key);
* map.remove(key);
* else
* map.put(key, newValue);
* }</pre>
* map.put(key, newValue);}</pre>
*
* <p>The default implementation may retry these steps when multiple
* threads attempt updates including potentially calling the remapping

66
jdk/src/java.base/share/classes/java/util/concurrent/ConcurrentSkipListMap.java

@ -58,6 +58,7 @@ import java.util.function.BiFunction;
import java.util.function.Consumer;
import java.util.function.BiConsumer;
import java.util.function.Function;
import java.util.function.Predicate;
/**
* A scalable concurrent {@link ConcurrentNavigableMap} implementation.
@ -2492,6 +2493,22 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
else
return (Spliterator<E>)((SubMap<?,E>)m).valueIterator();
}
public boolean removeIf(Predicate<? super E> filter) {
if (filter == null) throw new NullPointerException();
if (m instanceof ConcurrentSkipListMap)
return ((ConcurrentSkipListMap<?,E>)m).removeValueIf(filter);
// else use iterator
@SuppressWarnings("unchecked") Iterator<Map.Entry<Object,E>> it =
((SubMap<Object,E>)m).entryIterator();
boolean removed = false;
while (it.hasNext()) {
Map.Entry<Object,E> e = it.next();
E v = e.getValue();
if (filter.test(v) && m.remove(e.getKey(), v))
removed = true;
}
return removed;
}
}
static final class EntrySet<K1,V1> extends AbstractSet<Map.Entry<K1,V1>> {
@ -2554,6 +2571,20 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
return (Spliterator<Map.Entry<K1,V1>>)
((SubMap<K1,V1>)m).entryIterator();
}
public boolean removeIf(Predicate<? super Entry<K1, V1>> filter) {
if (filter == null) throw new NullPointerException();
if (m instanceof ConcurrentSkipListMap)
return ((ConcurrentSkipListMap<K1,V1>)m).removeEntryIf(filter);
// else use iterator
Iterator<Map.Entry<K1,V1>> it = ((SubMap<K1,V1>)m).entryIterator();
boolean removed = false;
while (it.hasNext()) {
Map.Entry<K1,V1> e = it.next();
if (filter.test(e) && m.remove(e.getKey(), e.getValue()))
removed = true;
}
return removed;
}
}
/**
@ -3266,6 +3297,41 @@ public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
}
}
/**
* Helper method for EntrySet.removeIf
*/
boolean removeEntryIf(Predicate<? super Entry<K, V>> function) {
if (function == null) throw new NullPointerException();
boolean removed = false;
for (Node<K,V> n = findFirst(); n != null; n = n.next) {
V v;
if ((v = n.getValidValue()) != null) {
K k = n.key;
Map.Entry<K,V> e = new AbstractMap.SimpleImmutableEntry<>(k, v);
if (function.test(e) && remove(k, v))
removed = true;
}
}
return removed;
}
/**
* Helper method for Values.removeIf
*/
boolean removeValueIf(Predicate<? super V> function) {
if (function == null) throw new NullPointerException();
boolean removed = false;
for (Node<K,V> n = findFirst(); n != null; n = n.next) {
V v;
if ((v = n.getValidValue()) != null) {
K k = n.key;
if (function.test(v) && remove(k, v))
removed = true;
}
}
return removed;
}
/**
* Base class providing common structure for Spliterators.
* (Although not all that much common functionality; as usual for

176
jdk/test/java/util/concurrent/ConcurrentMap/ConcurrentRemoveIf.java Normal file

@ -0,0 +1,176 @@
/*
* Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* @test
* @run testng ConcurrentRemoveIf
* @bug 8078645
* @summary Test removeIf on views of concurrent maps
*/
import org.testng.Assert;
import org.testng.annotations.AfterClass;
import org.testng.annotations.DataProvider;
import org.testng.annotations.Test;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentNavigableMap;
import java.util.concurrent.ConcurrentSkipListMap;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.function.Consumer;
import java.util.function.Supplier;
@Test
public class ConcurrentRemoveIf {
static final int K = 100;
static final int SIZE = 1000;
static final int HALF_SIZE = SIZE / 2;
@DataProvider(name = "String,Supplier<ConcurrentMap>,Runnable")
public static Object[][] spliteratorDataProvider() {
List<Object[]> rows = new ArrayList<>();
// ConcurrentMap classes to test
Map<String, Supplier<ConcurrentMap<Integer, Integer>>> maps = new HashMap<>();
maps.put("ConcurrentHashMap", ConcurrentHashMap::new);
maps.put("ConcurrentSkipListMap", ConcurrentSkipListMap::new);
// ConcurrentMap actions
Map<String, Consumer<ConcurrentMap<Integer, Integer>>> actions = new HashMap<>();
actions.put(".entrySet().removeIf()", m -> m.entrySet().removeIf(e -> e.getValue() == 0));
actions.put(".values().removeIf()", m -> m.values().removeIf(v -> v == 0));
// ConcurrentNavigableMap actions
Map<String, Consumer<ConcurrentNavigableMap<Integer, Integer>>> navActions = new HashMap<>();
navActions.put(".headMap()/tailMap().entrySet().removeIf()",
m -> {
ConcurrentMap<Integer, Integer> left = m.headMap(HALF_SIZE, false);
ConcurrentMap<Integer, Integer> right = m.tailMap(HALF_SIZE, true);
left.entrySet().removeIf(e -> e.getValue() == 0);
right.entrySet().removeIf(e -> e.getValue() == 0);
});
navActions.put(".headMap()/tailMap().values().removeIf()",
m -> {
ConcurrentMap<Integer, Integer> left = m.headMap(HALF_SIZE, false);
ConcurrentMap<Integer, Integer> right = m.tailMap(HALF_SIZE, true);
left.values().removeIf(v -> v == 0);
right.values().removeIf(v -> v == 0);
});
navActions.put(".descendingMap().entrySet().removeIf()",
m -> {
ConcurrentMap<Integer, Integer> dm = m.descendingMap();
dm.entrySet().removeIf(e -> e.getValue() == 0);
});
navActions.put(".descendingMap().values().removeIf()",
m -> {
ConcurrentMap<Integer, Integer> dm = m.descendingMap();
dm.values().removeIf(v -> v == 0);
});
for (Map.Entry<String, Supplier<ConcurrentMap<Integer, Integer>>> mapSupplier : maps.entrySet()) {
Supplier<ConcurrentMap<Integer, Integer>> sm = mapSupplier.getValue();
for (Map.Entry<String, Consumer<ConcurrentMap<Integer, Integer>>> action : actions.entrySet()) {
rows.add(new Object[]{
mapSupplier.getKey() + action.getKey(),
sm,
action.getValue()});
}
if (sm.get() instanceof ConcurrentNavigableMap) {
for (Map.Entry<String, Consumer<ConcurrentNavigableMap<Integer, Integer>>> action : navActions.entrySet()) {
rows.add(new Object[]{
mapSupplier.getKey() + action.getKey(),
sm,
action.getValue()});
}
}
}
return rows.toArray(new Object[0][]);
}
ExecutorService executorService = Executors.newCachedThreadPool();
@AfterClass
public void after() {
executorService.shutdown();
}
@Test(dataProvider = "String,Supplier<ConcurrentMap>,Runnable")
public void testMap(String desc, Supplier<ConcurrentMap<Integer, Integer>> ms, Consumer<ConcurrentMap<Integer, Integer>> action)
throws InterruptedException {
for (int i = 0; i < K; i++) {
testMap(ms.get(), action);
}
}
private void testMap(ConcurrentMap<Integer, Integer> map, Consumer<ConcurrentMap<Integer, Integer>> action)
throws InterruptedException {
// put 0's
fillMap(map, 0);
// To start working simultaneously
CyclicBarrier threadStarted = new CyclicBarrier(2);
// This task put 1's into map
CompletableFuture<Void> putter = CompletableFuture.runAsync(
awaitOn(threadStarted, () -> fillMap(map, 1)),
executorService);
// This task performs the map action to remove all 0's from map
CompletableFuture<Void> remover = CompletableFuture.runAsync(
awaitOn(threadStarted, () -> action.accept(map)),
executorService);
// Wait for both tasks to complete
CompletableFuture.allOf(putter, remover).join();
Assert.assertEquals(map.size(), SIZE, "Map size incorrect");
}
static void fillMap(ConcurrentMap<Integer, Integer> map, int value) {
for (int i = 0; i < SIZE; i++) {
map.put(i, value);
}
}
static Runnable awaitOn(CyclicBarrier threadStarted, Runnable r) {
return () -> {
try {
threadStarted.await();
}
catch (Exception e) {
throw new RuntimeException(e);
}
r.run();
};
}
}