telecom.util.collections

Class Collections

java.lang.Object

telecom.util.collections.Collections

public class Collections
extends java.lang.Object

Constructor Summary

Constructors

Constructor and Description
Collections()

Method Summary

Modifier and Type	Method and Description
static <K,V> boolean	addToMap(java.util.Map<K,java.util.List<V>> map, K key, V value) Adds a value to a multimap, represented as a map where the values are lists of objects.
static void	main(java.lang.String[] args)
static <T> T	poll(java.util.Collection<T> collection) Dequeues an element from the given collection.
static <T> java.util.Collection<T>	reservoirSampling(java.util.Collection<T> someCollection, int sampleSize) Applies reservoir sampling to a collection of items: http://www.geeksforgeeks.org/reservoir-sampling/
static java.util.List<int[]>	subsetsUpToSize(int collectionSize, int n) Enumerates all the subsets of indexes up to size 'n' for a collection of items of size 'collectionSize'.
static <K> java.lang.String	toString(IntHashMap<K> histogram) Return the full string representation of a IntHashMap

Methods inherited from class java.lang.Object

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

Constructor Detail

Collections

public Collections()

Method Detail

poll

public static <T> T poll(java.util.Collection<T> collection)

Dequeues an element from the given collection. It returns null if the collection is empty.

subsetsUpToSize

public static java.util.List<int[]> subsetsUpToSize(int collectionSize,
                                                    int n)

Enumerates all the subsets of indexes up to size 'n' for a collection of items of size 'collectionSize'.

Parameters:

collectionSize -

n -

Returns:

main

public static void main(java.lang.String[] args)

reservoirSampling

public static <T> java.util.Collection<T> reservoirSampling(java.util.Collection<T> someCollection,
                                                            int sampleSize)

Applies reservoir sampling to a collection of items: http://www.geeksforgeeks.org/reservoir-sampling/

Parameters:

someCollection -

sampleSize -

toString

public static <K> java.lang.String toString(IntHashMap<K> histogram)

Return the full string representation of a IntHashMap

Parameters:

histogram -

Returns:

addToMap

public static <K,V> boolean addToMap(java.util.Map<K,java.util.List<V>> map,
                                     K key,
                                     V value)

Adds a value to a multimap, represented as a map where the values are lists of objects.

Parameters:

map -

key -

value -

Returns:

true if the key already existed in the map.