oshi.util

Class MapUtil

java.lang.Object

oshi.util.MapUtil

public class MapUtil
extends Object

Allow Java 8 features on Java 7 HashMaps

Author:

widdis[at]gmail[dot]com

Method Summary

Modifier and Type	Method and Description
static <K,V> List<V>	createNewListIfAbsent(Map<K,List<V>> map, K key) If the specified key is not already associated with a value (or is mapped to null) associates it with a new List and returns it, else returns the current value.
static <K,V> V	getOrDefault(Map<K,V> map, K key, V defaultValue) Returns the value to which the specified key is mapped, or defaultValue if this map contains no mapping for the key.
static <K,V> V	putIfAbsent(Map<K,V> map, K key, V value) If the specified key is not already associated with a value (or is mapped to null) associates it with the given value and returns null, else returns the current value.

Methods inherited from class java.lang.Object

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

Method Detail

getOrDefault

public static <K,V> V getOrDefault(Map<K,V> map,
                                   K key,
                                   V defaultValue)

Returns the value to which the specified key is mapped, or defaultValue if this map contains no mapping for the key.

Type Parameters:

K - The map key type

V - The map value type

Parameters:

map - the map to use

key - the key whose associated value is to be returned

defaultValue - the default mapping of the key

Returns:

the value to which the specified key is mapped, or defaultValue if this map contains no mapping for the key

putIfAbsent

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

If the specified key is not already associated with a value (or is mapped to null) associates it with the given value and returns null, else returns the current value.

Type Parameters:

K - The map key type

V - The map value type

Parameters:

map - the map to use

key - key with which the specified value is to be associated

value - value to be associated with the specified key

Returns:

the previous value associated with the specified key, or null if there was no mapping for the key. (A null return can also indicate that the map previously associated null with the key, if the implementation supports null values.)

createNewListIfAbsent

public static <K,V> List<V> createNewListIfAbsent(Map<K,List<V>> map,
                                                  K key)

If the specified key is not already associated with a value (or is mapped to null) associates it with a new List and returns it, else returns the current value.

Type Parameters:

K - The map key type

V - The map value type in the list

Parameters:

map - the map to use

key - key with which the specified value is to be associated

Returns:

the previous value associated with the specified key, or a new list