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:

java.io.Serializable, java.lang.Cloneable, java.util.Map, IterableMap

public class CaseInsensitiveMap
extends AbstractHashedMap
implements java.io.Serializable, java.lang.Cloneable

A case-insensitive Map.

As entries are added to the map, keys are converted to all lowercase. A new key is compared to existing keys by comparing newKey.toString().toLower() to the lowercase values in the current KeySet.

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: 646777 $ $Date: 2008-04-10 13:33:15 +0100 (Thu, 10 Apr 2008) $

Author:

Commons-Collections team

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.commons.collections.map.AbstractHashedMap

AbstractHashedMap.EntrySet, AbstractHashedMap.EntrySetIterator, AbstractHashedMap.HashEntry, AbstractHashedMap.HashIterator, AbstractHashedMap.HashMapIterator, AbstractHashedMap.KeySet, AbstractHashedMap.KeySetIterator, AbstractHashedMap.Values, AbstractHashedMap.ValuesIterator

Nested classes/interfaces inherited from interface java.util.Map

java.util.Map.Entry

Field Summary

Fields inherited from class org.apache.commons.collections.map.AbstractHashedMap

data, DEFAULT_CAPACITY, DEFAULT_LOAD_FACTOR, DEFAULT_THRESHOLD, entrySet, GETKEY_INVALID, GETVALUE_INVALID, keySet, loadFactor, MAXIMUM_CAPACITY, modCount, NO_NEXT_ENTRY, NO_PREVIOUS_ENTRY, NULL, REMOVE_INVALID, SETVALUE_INVALID, size, threshold, values

Constructor Summary

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

CaseInsensitiveMap(int initialCapacity)
Constructs a new, empty map with the specified initial capacity.

CaseInsensitiveMap(int initialCapacity, float loadFactor)
Constructs a new, empty map with the specified initial capacity and load factor.

CaseInsensitiveMap(java.util.Map map)
Constructor copying elements from another map.

Method Summary

java.lang.Object	clone() Clones the map without cloning the keys or values.
protected java.lang.Object	convertKey(java.lang.Object key) Overrides convertKey() from AbstractHashedMap to convert keys to lower case.

Methods inherited from class org.apache.commons.collections.map.AbstractHashedMap

addEntry, addMapping, calculateNewCapacity, calculateThreshold, checkCapacity, clear, containsKey, containsValue, createEntry, createEntrySetIterator, createKeySetIterator, createValuesIterator, destroyEntry, doReadObject, doWriteObject, ensureCapacity, entryHashCode, entryKey, entryNext, entrySet, entryValue, equals, get, getEntry, hash, hashCode, hashIndex, init, isEmpty, isEqualKey, isEqualValue, keySet, mapIterator, put, putAll, remove, removeEntry, removeMapping, reuseEntry, size, toString, updateEntry, values

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

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:

java.lang.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:

java.lang.IllegalArgumentException - if the initial capacity is less than one

java.lang.IllegalArgumentException - if the load factor is less than zero

CaseInsensitiveMap

public CaseInsensitiveMap(java.util.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:

java.lang.NullPointerException - if the map is null

Method Detail

convertKey

protected java.lang.Object convertKey(java.lang.Object key)

Overrides convertKey() from AbstractHashedMap to convert keys to lower case.

Returns null if key is null.

Overrides:

convertKey in class AbstractHashedMap

Parameters:

key - the key convert

Returns:

the converted key

clone

public java.lang.Object clone()

Clones the map without cloning the keys or values.

Overrides:

clone in class AbstractHashedMap

Returns:

a shallow clone