reactor.netty.internal.util

Class MapUtils

java.lang.Object

reactor.netty.internal.util.MapUtils

public final class MapUtils
extends Object

This class contains temporary workarounds for Java 8 Map issues.

Note: This utility class is for internal use only. It can be removed at any time.

Since:

1.0.15

Author:

zimatars

Method Summary

Modifier and Type	Method and Description
static int	calculateInitialCapacity(int expectedSize) This is a temporary workaround for Java 8 issue https://bugs.openjdk.org/browse/JDK-8186958.
static <K,V> V	computeIfAbsent(Map<K,V> map, K key, Function<K,V> mappingFunction) This is a temporary workaround for Java 8 specific performance issue https://bugs.openjdk.org/browse/JDK-8161372.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

calculateInitialCapacity

public static int calculateInitialCapacity(int expectedSize)

This is a temporary workaround for Java 8 issue https://bugs.openjdk.org/browse/JDK-8186958. Fix is available in Java 19.

Calculate the initial capacity for the Map from the expected size and the default load factor for the Map (0.75).

Parameters:

expectedSize - the expected size

Returns:

the initial capacity for the Map

Since:

1.0.31

computeIfAbsent

public static <K,V> V computeIfAbsent(Map<K,V> map,
                                      K key,
                                      Function<K,V> mappingFunction)

This is a temporary workaround for Java 8 specific performance issue https://bugs.openjdk.org/browse/JDK-8161372. Fix is available in Java 9.

ConcurrentHashMap.computeIfAbsent(k,v) locks when k is present. Add pre-screen before locking inside computeIfAbsent.

Note: This utility is not for a general purpose usage. Carefully consider the removal operations from the map. If you have many remove operations that are critical, do not use this pre-screening.

Parameters:

map - the ConcurrentHashMap instance

key - key with which the specified value is to be associated

mappingFunction - the function to compute a value

Returns:

the current (existing or computed) value associated with the specified key, or null if the computed value is null