com.hazelcast.util

Class CollectionUtil

java.lang.Object

com.hazelcast.util.CollectionUtil

public final class CollectionUtil
extends Object

Various collection utility methods.

Method Summary

Modifier and Type	Method and Description
static <K,V> List<V>	addToValueList(Map<K,List<V>> map, K key, V value) Adds a value to a list of values in the map.
static <T> T	getItemAtPositionOrNull(Collection<T> collection, int position) Returns the n-th item or null if collection is smaller.
static boolean	isEmpty(Collection collection) Returns true if the given collection is null or empty, otherwise returns false.
static boolean	isNotEmpty(Collection collection) Returns true if the given collection is not null and not empty, otherwise returns false.
static <T> Collection<T>	nullToEmpty(Collection<T> collection) Returns an empty Collection if argument is null.
static <C> void	objectToDataCollection(Collection<C> objectCollection, Collection<Data> dataCollection, SerializationService serializationService, String errorMessage) Converts a collection of any type to a collection of Data.
static <C> Collection<Data>	objectToDataCollection(Collection<C> collection, SerializationService serializationService) Converts a collection of any type to a collection of Data.
static int[]	toIntArray(Collection<Integer> collection) Converts a Collection to a primitive int[] array.
static List<Integer>	toIntegerList(int[] array) Converts an int array to an Integer List.
static long[]	toLongArray(Collection<Long> collection) Converts a Collection to a primitive long[] array.

Methods inherited from class java.lang.Object

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

Method Detail

isEmpty

public static boolean isEmpty(Collection collection)

Returns true if the given collection is null or empty, otherwise returns false.

Parameters:

collection - the given collection

Returns:

true if collection is empty

isNotEmpty

public static boolean isNotEmpty(Collection collection)

Returns true if the given collection is not null and not empty, otherwise returns false.

Parameters:

collection - the given collection

Returns:

true if collection is not empty

addToValueList

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

Adds a value to a list of values in the map.

Creates a new list if no list is found for the key.

Parameters:

map - the given map of lists

key - the key of the target list

value - the value to add to the target list

Returns:

the updated list of values

getItemAtPositionOrNull

public static <T> T getItemAtPositionOrNull(Collection<T> collection,
                                            int position)

Returns the n-th item or null if collection is smaller.

Parameters:

collection - the given collection

position - position of the wanted item

Returns:

the item on position or null if the given collection is too small

Throws:

NullPointerException - if collection is null

objectToDataCollection

public static <C> Collection<Data> objectToDataCollection(Collection<C> collection,
                                                          SerializationService serializationService)

Converts a collection of any type to a collection of Data.

Parameters:

collection - the given collection

serializationService - will be used for converting object to Data

Returns:

collection of data

Throws:

NullPointerException - if collection is null or contains a null item

objectToDataCollection

public static <C> void objectToDataCollection(Collection<C> objectCollection,
                                              Collection<Data> dataCollection,
                                              SerializationService serializationService,
                                              String errorMessage)

Converts a collection of any type to a collection of Data.

Parameters:

objectCollection - object items

dataCollection - data items

serializationService - will be used for converting object to Data

errorMessage - the errorMessage when an item is null

Throws:

NullPointerException - if collection is null or contains a null item

toIntArray

public static int[] toIntArray(Collection<Integer> collection)

Converts a Collection to a primitive int[] array.

Parameters:

collection - the given collection

Returns:

a primitive int[] array

Throws:

NullPointerException - if collection is null

toLongArray

public static long[] toLongArray(Collection<Long> collection)

Converts a Collection to a primitive long[] array.

Parameters:

collection - the given collection

Returns:

a primitive long[] array

Throws:

NullPointerException - if collection is null

toIntegerList

public static List<Integer> toIntegerList(int[] array)

Converts an int array to an Integer List.

The returned collection can be modified after it is created; it isn't protected by an immutable wrapper.

Parameters:

array - the array

Returns:

the list. throws NullPointerException if array is null.

nullToEmpty

public static <T> Collection<T> nullToEmpty(Collection<T> collection)

Returns an empty Collection if argument is null.