org.apache.commons.collections4.map

Class CaseInsensitiveMap<K,V>

java.lang.Object

java.util.AbstractMap<K,V>

org.apache.commons.collections4.map.AbstractHashedMap<K,V>

org.apache.commons.collections4.map.CaseInsensitiveMap<K,V>

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.util.Map<K,V>, Get<K,V>, IterableGet<K,V>, IterableMap<K,V>, Put<K,V>

public class CaseInsensitiveMap<K,V>
extends AbstractHashedMap<K,V>
implements java.io.Serializable, java.lang.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<String, String> map = new CaseInsensitiveMap<String, String>();
  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}.

This map will violate the detail of various Map and map view contracts. As a general rule, don't compare this map to other maps. In particular, you can't use decorators like ListOrderedMap on it, which silently assume that these contracts are fulfilled.

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:

3.0

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class java.util.AbstractMap

java.util.AbstractMap.SimpleEntry<K,V>, java.util.AbstractMap.SimpleImmutableEntry<K,V>

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

java.util.Map.Entry<K,V>

Constructor Summary

Constructors

Constructor and Description
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<? extends K,? extends V> map) Constructor copying elements from another map.

Method Summary

Modifier and Type	Method and Description
CaseInsensitiveMap<K,V>	clone() Clones the map without cloning the keys or values.

Methods inherited from class org.apache.commons.collections4.map.AbstractHashedMap

clear, containsKey, containsValue, entrySet, equals, get, hashCode, isEmpty, keySet, mapIterator, put, putAll, remove, size, toString, values

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, putIfAbsent, remove, replace, replace, replaceAll

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 negative

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 negative

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

CaseInsensitiveMap

public CaseInsensitiveMap(java.util.Map<? extends K,? extends V> 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

clone

public CaseInsensitiveMap<K,V> clone()

Clones the map without cloning the keys or values.

Returns:

a shallow clone