Package org.apache.commons.collections.map

Class CaseInsensitiveMap

java.lang.Object
java.util.AbstractMap
org.apache.commons.collections.map.AbstractHashedMap
org.apache.commons.collections.map.CaseInsensitiveMap
All Implemented Interfaces:
Serializable, Cloneable, Map, IterableMap
public class CaseInsensitiveMap extends AbstractHashedMap implements Serializable, Cloneable
A case-insensitive Map.

Before keys are added to the map or compared to other existing keys, they are converted to all lowercase in a locale-independent fashion by using information from the Unicode data file.

Null keys are supported.

The keySet() method returns all lowercase keys, or nulls.

Example: 


  Map map = new CaseInsensitiveMap();
  map.put("One", "One");
  map.put("Two", "Two");
  map.put(null, "Three");
  map.put("one", "Four");
creates a CaseInsensitiveMap with three entries.
map.get(null) returns "Three" and map.get("ONE") returns "Four". The Set returned by keySet() equals {"one", "two", null}.

Note that CaseInsensitiveMap 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: 1713181 $ $Date: 2015-11-07 22:17:00 +0100 (Sat, 07 Nov 2015) $
Author:
Commons-Collections team
See Also:

  • Constructor Details

    • CaseInsensitiveMap

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

    • CaseInsensitiveMap

      public CaseInsensitiveMap(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

    • CaseInsensitiveMap

      public CaseInsensitiveMap(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

    • CaseInsensitiveMap

      public CaseInsensitiveMap(Map map)
      Constructor copying elements from another map.

      Keys will be converted to lower case strings, which may cause some entries to be removed (if string representation of keys differ only by character case).

      Parameters:
      map - the map to copy
      Throws:
      NullPointerException - if the map is null

  • Method Details