de.javagl.common.collections

Class Maps

java.lang.Object

de.javagl.common.collections.Maps

public class Maps
extends Object

Utility methods related to maps

Method Summary

Modifier and Type	Method and Description
static <K,E> void	addToList(Map<K,List<E>> map, K k, E e) Adds the given element to the list that is stored under the given key.
static <K,V> void	fillValues(Map<K,V> map, Iterable<? extends V> values) Fill the given map sequentially with the values from the given sequence.
static <T> Map<Integer,T>	fromElements(T... elements) Creates a map that maps consecutive integer values to the corresponding elements in the given array.
static <T> Map<Integer,T>	fromIterable(Iterable<? extends T> iterable) Creates a map that maps consecutive integer values to the elements in the given sequence, in the order in which they appear.
static <K,V> Map<K,V>	fromIterables(Iterable<? extends K> iterable0, Iterable<? extends V> iterable1) Creates a map that maps the elements of the first sequence to the corresponding elements in the second sequence.
static <K> Integer	getCount(Map<K,Integer> map, K k) Returns the value that is stored for the given key in the given map.
static <K> void	incrementCount(Map<K,Integer> map, K k) Increments the value that is stored for the given key in the given map by one, or sets it to 1 if there was no value stored for the given key.
static <K,V> Map<K,V>	unmodifiableCopy(Map<? extends K,? extends V> map) Creates an unmodifiable copy of the given map

Methods inherited from class java.lang.Object

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

Method Detail

incrementCount

public static <K> void incrementCount(Map<K,Integer> map,
                                      K k)

Increments the value that is stored for the given key in the given map by one, or sets it to 1 if there was no value stored for the given key.

Type Parameters:

K - The key type

Parameters:

map - The map

k - The key

getCount

public static <K> Integer getCount(Map<K,Integer> map,
                                   K k)

Returns the value that is stored for the given key in the given map. If there is no value stored, then 0 will be inserted into the map and returned

Type Parameters:

K - The key type

Parameters:

map - The map

k - The key

Returns:

The value

addToList

public static <K,E> void addToList(Map<K,List<E>> map,
                                   K k,
                                   E e)

Adds the given element to the list that is stored under the given key. If the list does not yet exist, it is created and inserted into the map.

Type Parameters:

K - The key type

E - The element type

Parameters:

map - The map

k - The key

e - The element

fillValues

public static <K,V> void fillValues(Map<K,V> map,
                                    Iterable<? extends V> values)

Fill the given map sequentially with the values from the given sequence. This method will iterate over all keys of the given map, and put the corresponding value element into the map. If the map is larger than the sequence, then the remaining entries will remain unaffected.

Type Parameters:

K - The key type

V - The value type

Parameters:

map - The map to fill

values - The values

fromElements

@SafeVarargs
public static <T> Map<Integer,T> fromElements(T... elements)

Creates a map that maps consecutive integer values to the corresponding elements in the given array.

Type Parameters:

T - The value type

Parameters:

elements - The elements

Returns:

The map

fromIterable

public static <T> Map<Integer,T> fromIterable(Iterable<? extends T> iterable)

Creates a map that maps consecutive integer values to the elements in the given sequence, in the order in which they appear.

Type Parameters:

T - The value type

Parameters:

iterable - The sequence

Returns:

The map

fromIterables

public static <K,V> Map<K,V> fromIterables(Iterable<? extends K> iterable0,
                                           Iterable<? extends V> iterable1)

Creates a map that maps the elements of the first sequence to the corresponding elements in the second sequence. If the given sequences have different lengths, then only the elements of the shorter sequence will be contained in the map.

Type Parameters:

K - The key type

V - The value type

Parameters:

iterable0 - The first sequence

iterable1 - The second sequence

Returns:

The map

unmodifiableCopy

public static <K,V> Map<K,V> unmodifiableCopy(Map<? extends K,? extends V> map)

Creates an unmodifiable copy of the given map

Type Parameters:

K - The key type

V - The value type

Parameters:

map - The input map

Returns:

The resulting map