org.apache.flink.util

Class CollectionUtil

java.lang.Object

org.apache.flink.util.CollectionUtil

@Internal
public final class CollectionUtil
extends Object

Simple utility to work with Java collections.

Field Summary

Fields

Modifier and Type	Field and Description
static int	MAX_ARRAY_SIZE A safe maximum size for arrays in the JVM.

Method Summary

Modifier and Type	Method and Description
static boolean	isNullOrEmpty(Collection<?> collection)
static boolean	isNullOrEmpty(Map<?,?> map)
static <T,R> java.util.stream.Stream<R>	mapWithIndex(Collection<T> input, java.util.function.BiFunction<T,Integer,R> mapper)
static <T> Collection<List<T>>	partition(Collection<T> elements, int numBuckets) Partition a collection into approximately n buckets.
static <I,O> Collection<O>	project(Collection<I> collection, java.util.function.Function<I,O> projector)

Methods inherited from class java.lang.Object

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

Field Detail

MAX_ARRAY_SIZE

public static final int MAX_ARRAY_SIZE

A safe maximum size for arrays in the JVM.

See Also:

Constant Field Values

Method Detail

isNullOrEmpty

public static boolean isNullOrEmpty(Collection<?> collection)

isNullOrEmpty

public static boolean isNullOrEmpty(Map<?,?> map)

mapWithIndex

public static <T,R> java.util.stream.Stream<R> mapWithIndex(Collection<T> input,
                                                            java.util.function.BiFunction<T,Integer,R> mapper)

partition

public static <T> Collection<List<T>> partition(Collection<T> elements,
                                                int numBuckets)

Partition a collection into approximately n buckets.

project

public static <I,O> Collection<O> project(Collection<I> collection,
                                          java.util.function.Function<I,O> projector)