Class ObjectMap<K,V>

java.lang.Object
com.esotericsoftware.kryo.util.ObjectMap<K,V>

public class ObjectMap<K,V> extends Object
An unordered map. This implementation is a cuckoo hash map using 3 hashes, random walking, and a small stash for problematic keys. Null keys are not allowed. Null values are allowed. No allocation is done except when growing the table size.

This map performs very fast get, containsKey, and remove (typically O(1), worst case O(log(n))). Put may be a bit slower, depending on hash collisions. Load factors greater than 0.91 greatly increase the chances the map will have to rehash to the next higher POT size.
  • Field Details

    • size

      public int size
  • Constructor Details

    • ObjectMap

      public ObjectMap()
      Creates a new map with an initial capacity of 32 and a load factor of 0.8. This map will hold 25 items before growing the backing table.
    • ObjectMap

      public ObjectMap(int initialCapacity)
      Creates a new map with a load factor of 0.8. This map will hold initialCapacity * 0.8 items before growing the backing table.
    • ObjectMap

      public ObjectMap(int initialCapacity, float loadFactor)
      Creates a new map with the specified initial capacity and load factor. This map will hold initialCapacity * loadFactor items before growing the backing table.
  • Method Details

    • put

      public V put(K key, V value)
      Returns the old value associated with the specified key, or null.
    • putAll

      public void putAll(ObjectMap<K,V> map)
    • get

      public V get(K key)
    • remove

      public V remove(K key)
    • clear

      public void clear()
    • containsValue

      public boolean containsValue(Object value, boolean identity)
      Returns true if the specified value is in the map. Note this traverses the entire map and compares every value, which may be an expensive operation.
      Parameters:
      identity - If true, uses == to compare the specified value with values in the map. If false, uses Object.equals(Object).
    • containsKey

      public boolean containsKey(K key)
    • findKey

      public K findKey(Object value, boolean identity)
      Returns the key for the specified value, or null if it is not in the map. Note this traverses the entire map and compares every value, which may be an expensive operation.
      Parameters:
      identity - If true, uses == to compare the specified value with values in the map. If false, uses Object.equals(Object).
    • ensureCapacity

      public void ensureCapacity(int additionalCapacity)
      Increases the size of the backing array to acommodate the specified number of additional items. Useful before adding many items to avoid multiple backing array resizes.
    • toString

      public String toString()
      Overrides:
      toString in class Object
    • entries

      public ObjectMap.Entries<K,V> entries()
      Returns an iterator for the entries in the map. Remove is supported. Note that the same iterator instance is returned each time this method is called. Use the ObjectMap.Entries constructor for nested or multithreaded iteration.
    • values

      public ObjectMap.Values<V> values()
      Returns an iterator for the values in the map. Remove is supported. Note that the same iterator instance is returned each time this method is called. Use the ObjectMap.Entries constructor for nested or multithreaded iteration.
    • keys

      public ObjectMap.Keys<K> keys()
      Returns an iterator for the keys in the map. Remove is supported. Note that the same iterator instance is returned each time this method is called. Use the ObjectMap.Entries constructor for nested or multithreaded iteration.
    • nextPowerOfTwo

      public static int nextPowerOfTwo(int value)