de.alpharogroup.collections.map

Class MapExtensions

java.lang.Object

de.alpharogroup.collections.map.MapExtensions

public class MapExtensions
extends Object

Extensions class for use with Map objects.

Version:

1.0

Author:

Asterios Raptis

Constructor Summary

Constructors

Constructor and Description
MapExtensions()

Method Summary

Modifier and Type	Method and Description
static <K,V> K	getKeyFromValue(Map<K,V> map, V value) Returns the first founded key from the given value or null if nothing is found.
static <K,V> Collection<K>	getKeysFromValue(Map<K,V> map, V value) Returns a Collection from all founded keys from the given value or null if nothing found.
static Map<Integer,Map<String,String>>	newAssosiativeArrayMap() Factory method for Map that acts like a javascript associative array.
static <K,V> ConcurrentHashMap<K,V>	newConcurrentHashMap() Factory method for create a new ConcurrentHashMap.
static <K,V> ConcurrentHashMap<K,V>	newConcurrentHashMap(int initialCapacity) Factory method for create a new ConcurrentHashMap.
static <K,V> Map<K,V>	newHashMap() Factory method for create a new HashMap.
static <K,V> Map<K,V>	newHashMap(int initialCapacity) Factory method for create a new HashMap.
static <K,V> Map<K,V>	newLazyMap() Factory method for create a new LazyMap from commons-collections4.
static <K,V> void	printMap(Map<K,V> msg) The Method printMap prints the HashMap to the console.
static <T> Map<T,T>	toGenericMap(T[][] twoDimArray) Converts a two dimensional Array to a Map.
static Map<String,String>	toMap(String[][] twoDimArray) Converts a two dimensional String Array to a Map.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MapExtensions

public MapExtensions()

Method Detail

getKeyFromValue

public static <K,V> K getKeyFromValue(Map<K,V> map,
                                      V value)

Returns the first founded key from the given value or null if nothing is found.

Type Parameters:

K - the generic type of the key

V - the generic type of the value

Parameters:

map - The Map.

value - The value.

Returns:

Returns the first key from the given value or null if nothing found.

getKeysFromValue

public static <K,V> Collection<K> getKeysFromValue(Map<K,V> map,
                                                   V value)

Returns a Collection from all founded keys from the given value or null if nothing found.

Type Parameters:

K - the generic type of the key

V - the generic type of the value

Parameters:

map - The Map.

value - The value.

Returns:

Returns the key from the given value or an empty Collection if nothing found.

newAssosiativeArrayMap

public static Map<Integer,Map<String,String>> newAssosiativeArrayMap()

Factory method for Map that acts like a javascript associative array. This Map is the counterpart for the associative array in js. For instance: in js you can create and fetch associative arrays like this:

 $arrayObj[0]['firstName'] = 'Albert';
 $arrayObj[0]['lastName'] = 'Einstein';
 $arrayObj[1]['firstName'] = 'Neil';
 $arrayObj[0]['lastName'] = 'Armstrong';
 

With this method you can do the same like this:

 final Map<Integer, Map<String, String>> arrayMap = MapExtensions.newAssosiativeArrayMap();

 arrayMap.get(0).put("firstName", "Albert");
 arrayMap.get(0).put("lastName", "Einstein");
 arrayMap.get(1).put("firstName", "Neil");
 arrayMap.get(1).put("lastName", "Armstrong");
 

Returns:

The Map that acts like a javascript associative array.

newConcurrentHashMap

public static <K,V> ConcurrentHashMap<K,V> newConcurrentHashMap()

Factory method for create a new ConcurrentHashMap.

Type Parameters:

K - the generic type of the key

V - the generic type of the value

Returns:

The new ConcurrentHashMap.

newConcurrentHashMap

public static <K,V> ConcurrentHashMap<K,V> newConcurrentHashMap(int initialCapacity)

Factory method for create a new ConcurrentHashMap.

Type Parameters:

K - the generic type of the key

V - the generic type of the value

Parameters:

initialCapacity - the initial capacity

Returns:

The new ConcurrentHashMap.

newHashMap

public static <K,V> Map<K,V> newHashMap()

Factory method for create a new HashMap.

Type Parameters:

K - the generic type of the key

V - the generic type of the value

Returns:

The new HashMap.

newHashMap

public static <K,V> Map<K,V> newHashMap(int initialCapacity)

Factory method for create a new HashMap.

Type Parameters:

K - the generic type of the key

V - the generic type of the value

Parameters:

initialCapacity - the initial capacity

Returns:

The new HashMap.

newLazyMap

public static <K,V> Map<K,V> newLazyMap()

Factory method for create a new LazyMap from commons-collections4.

Type Parameters:

K - the generic type of the key

V - the generic type of the value

Returns:

The new LazyMap.

printMap

public static <K,V> void printMap(Map<K,V> msg)

The Method printMap prints the HashMap to the console.

Type Parameters:

K - the generic type of the key

V - the generic type of the value

Parameters:

msg - The map to print.

toGenericMap

public static <T> Map<T,T> toGenericMap(T[][] twoDimArray)

Converts a two dimensional Array to a Map.

Type Parameters:

T - the generic type

Parameters:

twoDimArray - The two dimensional Array.

Returns:

The map produced from the two dimensional Array.

toMap

public static Map<String,String> toMap(String[][] twoDimArray)

Converts a two dimensional String Array to a Map.

Parameters:

twoDimArray - The two dimensional String Array.

Returns:

The map produced from the two dimensional String Array.