Package org.apache.commons.collections4.map

Class HashedMap<K,​V>

  • Type Parameters:
    K - the type of the keys in this map
    V - the type of the values in this map
    All Implemented Interfaces:
    Serializable, Cloneable, Map<K,​V>, Get<K,​V>, IterableGet<K,​V>, IterableMap<K,​V>, Put<K,​V>
    public class HashedMap<K,​V>
extends AbstractHashedMap<K,​V>
implements Serializable, Cloneable
    A Map implementation that is a general purpose alternative to HashMap.

    This implementation improves on the JDK1.4 HashMap by adding the MapIterator functionality and many methods for subclassing.

    Note that HashedMap is not synchronized and is not thread-safe. If you wish to use this map from multiple threads concurrently, you must use appropriate synchronization. The simplest approach is to wrap this map using Collections.synchronizedMap(Map). This class may throw exceptions when accessed by concurrent threads without synchronization.

    Since:
    3.0
    See Also:
    Serialized Form

    • Constructor Detail

      • HashedMap

        public HashedMap()
        Constructs a new empty map with default size and load factor.

      • HashedMap

        public HashedMap​(int initialCapacity)
        Constructs a new, empty map with the specified initial capacity.
        Parameters:
        initialCapacity - the initial capacity
        Throws:
        IllegalArgumentException - if the initial capacity is negative

      • HashedMap

        public HashedMap​(int initialCapacity,
                 float loadFactor)
        Constructs a new, empty map with the specified initial capacity and load factor.
        Parameters:
        initialCapacity - the initial capacity
        loadFactor - the load factor
        Throws:
        IllegalArgumentException - if the initial capacity is negative
        IllegalArgumentException - if the load factor is less than zero

      • HashedMap

        public HashedMap​(Map<? extends K,​? extends V> map)
        Constructor copying elements from another map.
        Parameters:
        map - the map to copy
        Throws:
        NullPointerException - if the map is null

    • Method Detail