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8225339: Optimize HashMap.keySet()/HashMap.values()/HashSet toArray() methods

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Reviewed-by: rriggs, redestad, smarks
This commit is contained in:
Tagir F. Valeev 2019-06-14 05:02:58 +00:00
parent 51cf24fcc0
commit 822c02437a
5 changed files with 387 additions and 3 deletions
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88
src/java.base/share/classes/java/util/HashMap.java
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2019, 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
@ -911,6 +911,74 @@ public class HashMap<K,V> extends AbstractMap<K,V>
return ks;
}
/**
* Prepares the array for {@link Collection#toArray(Object[])} implementation.
* If supplied array is smaller than this map size, a new array is allocated.
* If supplied array is bigger than this map size, a null is written at size index.
*
* @param a an original array passed to {@code toArray()} method
* @param <T> type of array elements
* @return an array ready to be filled and returned from {@code toArray()} method.
*/
@SuppressWarnings("unchecked")
final <T> T[] prepareArray(T[] a) {
int size = this.size;
if (a.length < size) {
return (T[]) java.lang.reflect.Array
.newInstance(a.getClass().getComponentType(), size);
}
if (a.length > size) {
a[size] = null;
}
return a;
}
/**
* Fills an array with this map keys and returns it. This method assumes
* that input array is big enough to fit all the keys. Use
* {@link #prepareArray(Object[])} to ensure this.
*
* @param a an array to fill
* @param <T> type of array elements
* @return supplied array
*/
<T> T[] keysToArray(T[] a) {
Object[] r = a;
Node<K,V>[] tab;
int idx = 0;
if (size > 0 && (tab = table) != null) {
for (Node<K,V> e : tab) {
for (; e != null; e = e.next) {
r[idx++] = e.key;
}
}
}
return a;
}
/**
* Fills an array with this map values and returns it. This method assumes
* that input array is big enough to fit all the values. Use
* {@link #prepareArray(Object[])} to ensure this.
*
* @param a an array to fill
* @param <T> type of array elements
* @return supplied array
*/
<T> T[] valuesToArray(T[] a) {
Object[] r = a;
Node<K,V>[] tab;
int idx = 0;
if (size > 0 && (tab = table) != null) {
for (Node<K,V> e : tab) {
for (; e != null; e = e.next) {
r[idx++] = e.value;
}
}
}
return a;
}
final class KeySet extends AbstractSet<K> {
public final int size() { return size; }
public final void clear() { HashMap.this.clear(); }
@ -922,6 +990,15 @@ public class HashMap<K,V> extends AbstractMap<K,V>
public final Spliterator<K> spliterator() {
return new KeySpliterator<>(HashMap.this, 0, -1, 0, 0);
}
public Object[] toArray() {
return keysToArray(new Object[size]);
}
public <T> T[] toArray(T[] a) {
return keysToArray(prepareArray(a));
}
public final void forEach(Consumer<? super K> action) {
Node<K,V>[] tab;
if (action == null)
@ -970,6 +1047,15 @@ public class HashMap<K,V> extends AbstractMap<K,V>
public final Spliterator<V> spliterator() {
return new ValueSpliterator<>(HashMap.this, 0, -1, 0, 0);
}
public Object[] toArray() {
return valuesToArray(new Object[size]);
}
public <T> T[] toArray(T[] a) {
return valuesToArray(prepareArray(a));
}
public final void forEach(Consumer<? super V> action) {
Node<K,V>[] tab;
if (action == null)

12
src/java.base/share/classes/java/util/HashSet.java
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2019, 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
@ -358,4 +358,14 @@ public class HashSet<E>
public Spliterator<E> spliterator() {
return new HashMap.KeySpliterator<>(map, 0, -1, 0, 0);
}
@Override
public Object[] toArray() {
return map.keysToArray(new Object[map.size()]);
}
@Override
public <T> T[] toArray(T[] a) {
return map.keysToArray(map.prepareArray(a));
}
}

40
src/java.base/share/classes/java/util/LinkedHashMap.java
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2019, 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
@ -536,6 +536,26 @@ public class LinkedHashMap<K,V>
return ks;
}
@Override
final <T> T[] keysToArray(T[] a) {
Object[] r = a;
int idx = 0;
for (LinkedHashMap.Entry<K,V> e = head; e != null; e = e.after) {
r[idx++] = e.key;
}
return a;
}
@Override
final <T> T[] valuesToArray(T[] a) {
Object[] r = a;
int idx = 0;
for (LinkedHashMap.Entry<K,V> e = head; e != null; e = e.after) {
r[idx++] = e.value;
}
return a;
}
final class LinkedKeySet extends AbstractSet<K> {
public final int size() { return size; }
public final void clear() { LinkedHashMap.this.clear(); }
@ -551,6 +571,15 @@ public class LinkedHashMap<K,V>
Spliterator.ORDERED |
Spliterator.DISTINCT);
}
public Object[] toArray() {
return keysToArray(new Object[size]);
}
public <T> T[] toArray(T[] a) {
return keysToArray(prepareArray(a));
}
public final void forEach(Consumer<? super K> action) {
if (action == null)
throw new NullPointerException();
@ -600,6 +629,15 @@ public class LinkedHashMap<K,V>
return Spliterators.spliterator(this, Spliterator.SIZED |
Spliterator.ORDERED);
}
public Object[] toArray() {
return valuesToArray(new Object[size]);
}
public <T> T[] toArray(T[] a) {
return valuesToArray(prepareArray(a));
}
public final void forEach(Consumer<? super V> action) {
if (action == null)
throw new NullPointerException();

155
test/jdk/java/util/HashMap/ToArray.java Normal file
View file

@ -0,0 +1,155 @@
/*
* Copyright (c) 2019, 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.
*/
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.stream.LongStream;
/*
* @test
* @summary HashMap.toArray() behavior tests
* @author tvaleev
*/
public class ToArray {
public static void main(String[] args) {
checkMap(false);
checkMap(true);
checkSet(false);
checkSet(true);
}
private static <T extends Comparable<T>> void checkToArray(String message, T[] expected, Collection<T> collection,
boolean ignoreOrder) {
if (ignoreOrder) {
Arrays.sort(expected);
}
checkToObjectArray(message, expected, collection, ignoreOrder);
checkToTypedArray(message, expected, Arrays.copyOf(expected, 0), collection, ignoreOrder);
checkToTypedArray(message, expected, expected.clone(), collection, ignoreOrder);
if (expected.length > 0) {
T[] biggerArray = Arrays.copyOf(expected, expected.length * 2);
System.arraycopy(expected, 0, biggerArray, expected.length, expected.length);
checkToTypedArray(message, expected, biggerArray, collection, ignoreOrder);
}
}
private static <T extends Comparable<T>> void checkToTypedArray(String message, T[] expected, T[] inputArray,
Collection<T> collection, boolean ignoreOrder) {
T[] res = collection.toArray(inputArray);
if (expected.length <= inputArray.length && res != inputArray) {
throw new AssertionError(message + ": not the same array returned");
}
if (res.getClass() != expected.getClass()) {
throw new AssertionError(message + ": wrong class returned: " + res.getClass());
}
if (res.length < expected.length) {
throw new AssertionError(message + ": length is smaller than expected: " + res.length + " < " + expected.length);
}
if (ignoreOrder) {
Arrays.sort(res, 0, Math.min(res.length, expected.length));
}
if (inputArray.length <= expected.length) {
if (!Arrays.equals(res, expected)) {
throw new AssertionError(message + ": not equal: " + Arrays.toString(expected) + " != " +
Arrays.toString(res));
}
} else {
int mismatch = Arrays.mismatch(expected, res);
if (mismatch != expected.length) {
throw new AssertionError(message + ": mismatch at " + mismatch);
}
if (res[expected.length] != null) {
throw new AssertionError(message + ": no null at position " + expected.length);
}
// The tail of bigger array after expected.length position must be untouched
mismatch = Arrays
.mismatch(expected, 1, expected.length, res, expected.length + 1, res.length);
if (mismatch != -1) {
throw new AssertionError(message + ": mismatch at " + mismatch);
}
}
}
private static <T extends Comparable<T>> void checkToObjectArray(String message, T[] expected,
Collection<T> collection, boolean ignoreOrder) {
Object[] objects = collection.toArray();
if (objects.getClass() != Object[].class) {
throw new AssertionError(message + ": wrong class returned: " + objects.getClass());
}
if (ignoreOrder) {
Arrays.sort(objects);
}
int mismatch = Arrays.mismatch(expected, objects);
if (mismatch != -1) {
throw new AssertionError(message + ": mismatch at " + mismatch);
}
}
private static void checkMap(boolean ordered) {
Map<String, String> map = ordered ? new LinkedHashMap<>() : new HashMap<>();
checkToArray("Empty-keys", new String[0], map.keySet(), !ordered);
checkToArray("Empty-values", new String[0], map.values(), !ordered);
List<String> keys = new ArrayList<>();
List<String> values = new ArrayList<>();
for (int i = 0; i < 100; i++) {
keys.add(String.valueOf(i));
values.add(String.valueOf(i * 2));
map.put(String.valueOf(i), String.valueOf(i * 2));
checkToArray(i + "-keys", keys.toArray(new String[0]), map.keySet(), !ordered);
checkToArray(i + "-values", values.toArray(new String[0]), map.values(), !ordered);
}
map.clear();
checkToArray("Empty-keys", new String[0], map.keySet(), !ordered);
checkToArray("Empty-values", new String[0], map.values(), !ordered);
}
private static void checkSet(boolean ordered) {
Collection<String> set = ordered ? new LinkedHashSet<>() : new HashSet<>();
checkToArray("Empty", new String[0], set, !ordered);
set.add("foo");
checkToArray("One", new String[]{"foo"}, set, !ordered);
set.add("bar");
checkToArray("Two", new String[]{"foo", "bar"}, set, !ordered);
Collection<Long> longSet = ordered ? new LinkedHashSet<>() : new HashSet<>();
for (int x = 0; x < 100; x++) {
longSet.add((long) x);
}
checkToArray("100", LongStream.range(0, 100).boxed().toArray(Long[]::new), longSet, !ordered);
longSet.clear();
checkToArray("After clear", new Long[0], longSet, !ordered);
for (int x = 0; x < 100; x++) {
longSet.add(((long) x) | (((long) x) << 32));
}
checkToArray("Collisions", LongStream.range(0, 100).mapToObj(x -> x | (x << 32))
.toArray(Long[]::new), longSet, !ordered);
}
}

95
test/micro/org/openjdk/bench/java/util/HashMapToArray.java Normal file
View file

@ -0,0 +1,95 @@
/*
* Copyright (c) 2019, 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.
*/
package org.openjdk.bench.java.util;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Param;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.Warmup;
import java.util.Arrays;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@Warmup(iterations = 5, time = 500, timeUnit = TimeUnit.MILLISECONDS)
@Measurement(iterations = 10, time = 500, timeUnit = TimeUnit.MILLISECONDS)
@Fork(3)
@State(Scope.Thread)
public class HashMapToArray {
@Param({"0", "1", "10", "1000", "100000"})
public int size;
@Param({"HashMap", "LinkedHashMap"})
public String mapType;
private Map<Integer, Integer> map;
@Setup
public void setup() {
switch (mapType) {
case "HashMap":
map = new HashMap<>();
break;
case "LinkedHashMap":
map = new LinkedHashMap<>();
break;
default:
throw new IllegalStateException();
}
for (int i = 0; i < size; i++) {
map.put(i, i * i);
}
}
@Benchmark
public Object[] testKeySetToArray() {
return map.keySet().toArray();
}
@Benchmark
public Object[] testKeySetToArrayTyped() {
return map.keySet().toArray(new Integer[0]);
}
@Benchmark
public Object[] testValuesToArray() {
return map.values().toArray();
}
@Benchmark
public Object[] testValuesToArrayTyped() {
return map.values().toArray(new Integer[0]);
}
}