Top Description Inners Constructors Methods

com.google.common.collect

public final Class Collections2

Class Inheritance

extends Object

java.lang.Object
com.google.common.collect.Collections2

Annotations

@GwtCompatible
@ElementTypesAreNonnullByDefault

Static Imports

com.google.common.base.Preconditions.checkArgument, .Preconditions.checkNotNull, com.google.common.collect.CollectPreconditions.checkNonnegative, java.util.Objects.requireNonNull

Provides static methods for working with Collection instances.

Java 8+ users: several common uses for this class are now more comprehensively addressed by the new java.util.stream.Stream library. Read the method documentation below for comparisons. These methods are not being deprecated, but we gently encourage you to migrate to streams.

Authors: Chris Povirk, Mike Bostock, Jared Levy
Since: 2.0

Nested and Inner Type Summary

Modifier and Type	Class and Description
pack-priv static class	Collections2.FilteredCollection<E extends @Nullable Object>
private static class	Collections2.OrderedPermutationCollection<E>
private static class	Collections2.OrderedPermutationIterator<E>
private static class	Collections2.PermutationCollection<E>
private static class	Collections2.PermutationIterator<E>
pack-priv static class	Collections2.TransformedCollection<F extends @Nullable Object, T extends @Nullable Object>

Constructor Summary

Access	Constructor and Description
private	Collections2()

Method Summary

Modifier and Type	Method and Description
pack-priv static boolean	containsAllImpl(Collection<?> a collection which might contain all elements in `c` self, Collection<?> a collection whose elements might be contained by `self` c) Returns `true` if the collection `self` contains all of the elements in the collection `c`.
public static <E extends @Nullable Object> Collection<E>	filter(Collection<E> unfiltered, Predicate<? super E> predicate) Returns the elements of `unfiltered` that satisfy a predicate.
private static boolean	isPermutation(List<?> first, List<?> second) Returns `true` if the second list is a permutation of the first.
pack-priv static StringBuilder	newStringBuilderForCollection(int size) Returns best-effort-sized StringBuilder based on the given collection size.
public static <E extends Comparable<? super E>> Collection<List<E>>	Returns: an immutable `Collection` containing all the different permutations of the original iterable. orderedPermutations(Iterable<E> the original iterable whose elements have to be permuted. elements) Returns a `Collection` of all the permutations of the specified `Iterable`.
public static <E> Collection<List<E>>	Returns: an immutable `Collection` containing all the different permutations of the original iterable. orderedPermutations(Iterable<E> the original iterable whose elements have to be permuted. elements, Comparator<? super E> a comparator for the iterable's elements. comparator) Returns a `Collection` of all the permutations of the specified `Iterable` using the specified `Comparator` for establishing the lexicographical ordering.
public static <E> Collection<List<E>>	Returns: an immutable `Collection` containing all the different permutations of the original collection. permutations(Collection<E> the original collection whose elements have to be permuted. elements) Returns a `Collection` of all the permutations of the specified `Collection`.
pack-priv static boolean	safeContains(Collection<?> collection, Object object) Delegates to `Collection#contains`.
pack-priv static boolean	safeRemove(Collection<?> collection, Object object) Delegates to `Collection#remove`.
pack-priv static String	toStringImpl(final Collection<?> collection) An implementation of `Collection#toString()`.
public static <F extends @Nullable Object, T extends @Nullable Object> Collection<T>	transform(Collection<F> fromCollection, Function<? super F, T> function) Returns a collection that applies `function` to each element of `fromCollection`.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait