Package org.apache.commons.collections.map

Class HashedMap

java.lang.Object
java.util.AbstractMap
org.apache.commons.collections.map.AbstractHashedMap
org.apache.commons.collections.map.HashedMap
All Implemented Interfaces:
Serializable, Cloneable, Map, IterableMap
public class HashedMap extends AbstractHashedMap 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:
Commons Collections 3.0
Version:
$Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
Author:
Stephen Colebourne
See Also:

  • Constructor Details

    • 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 less than one

    • 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 less than one
      IllegalArgumentException - if the load factor is less than zero

    • HashedMap

      public HashedMap(Map map)
      Constructor copying elements from another map.
      Parameters:
      map - the map to copy
      Throws:
      NullPointerException - if the map is null

  • Method Details

    • clone

      public Object clone()
      Clones the map without cloning the keys or values.
      Overrides:
      clone in class AbstractHashedMap
      Returns:
      a shallow clone