Class ConcurrentOpenHashMap<K,​V>

  • Type Parameters:
    V -

    public class ConcurrentOpenHashMap<K,​V>
    extends java.lang.Object
    Concurrent hash map.

    Provides similar methods as a ConcurrentMap<K,V> but since it's an open hash map with linear probing, no node allocations are required to store the values
    WARN: method forEach do not guarantee thread safety, nor do the keys and values method.
    The forEach method is specifically designed for single-threaded usage. When iterating over a map with concurrent writes, it becomes possible for new values to be either observed or not observed. There is no guarantee that if we write value1 and value2, and are able to see value2, then we will also see value1. In some cases, it is even possible to encounter two mappings with the same key, leading the keys method to return a List containing two identical keys.
    It is crucial to understand that the results obtained from aggregate status methods such as keys and values are typically reliable only when the map is not undergoing concurrent updates from other threads. When concurrent updates are involved, the results of these methods reflect transient states that may be suitable for monitoring or estimation purposes, but not for program control.

    • Constructor Detail

      • ConcurrentOpenHashMap

        public ConcurrentOpenHashMap()
      • ConcurrentOpenHashMap

        public ConcurrentOpenHashMap​(int expectedItems)
      • ConcurrentOpenHashMap

        public ConcurrentOpenHashMap​(int expectedItems,
                                     int concurrencyLevel)
      • ConcurrentOpenHashMap

        public ConcurrentOpenHashMap​(int expectedItems,
                                     int concurrencyLevel,
                                     float mapFillFactor,
                                     float mapIdleFactor,
                                     boolean autoShrink,
                                     float expandFactor,
                                     float shrinkFactor)
    • Method Detail

      • getUsedBucketCount

        long getUsedBucketCount()
      • size

        public long size()
      • capacity

        public long capacity()
      • isEmpty

        public boolean isEmpty()
      • get

        public V get​(K key)
      • containsKey

        public boolean containsKey​(K key)
      • put

        public V put​(K key,
                     V value)
      • putIfAbsent

        public V putIfAbsent​(K key,
                             V value)
      • computeIfAbsent

        public V computeIfAbsent​(K key,
                                 java.util.function.Function<K,​V> provider)
      • remove

        public V remove​(K key)
      • remove

        public boolean remove​(K key,
                              java.lang.Object value)
      • clear

        public void clear()
      • forEach

        public void forEach​(java.util.function.BiConsumer<? super K,​? super V> processor)
        Iterate over all the entries in the map and apply the processor function to each of them.

        Warning: Do Not Guarantee Thread-Safety.

        processor - the function to apply to each entry
      • removeIf

        public int removeIf​(java.util.function.BiPredicate<K,​V> filter)
      • keys

        public java.util.List<K> keys()
        a new list of all keys (makes a copy)
      • values

        public java.util.List<V> values()
      • hash

        static final <K> long hash​(K key)
      • signSafeMod

        static final int signSafeMod​(long n,
                                     int max)