@ParametersAreNonnullByDefault

Package com.google.common.collect

This package contains generic collection interfaces and implementations, and other utilities for working with collections. It is a part of the open-source Guava libraries.

Collection Types

BiMap

An extension of Map that guarantees the uniqueness of its values as well as that of its keys. This is sometimes called an "invertible map," since the restriction on values enables it to support an inverse view -- which is another instance of BiMap.

Multiset

An extension of Collection that may contain duplicate values like a List, yet has order-independent equality like a Set. One typical use for a multiset is to represent a histogram.

Multimap

A new type, which is similar to Map, but may contain multiple entries with the same key. Some behaviors of Multimap are left unspecified and are provided only by the subtypes mentioned below.

ListMultimap

An extension of Multimap which permits duplicate entries, supports random access of values for a particular key, and has partially order-dependent equality as defined by ListMultimap.equals(Object). ListMultimap takes its name from the fact that the collection of values associated with a given key fulfills the List contract.

SetMultimap

An extension of Multimap which has order-independent equality and does not allow duplicate entries; that is, while a key may appear twice in a SetMultimap, each must map to a different value. SetMultimap takes its name from the fact that the collection of values associated with a given key fulfills the Set contract.

SortedSetMultimap

An extension of SetMultimap for which the collection values associated with a given key is a SortedSet.

Table

A new type, which is similar to Map, but which indexes its values by an ordered pair of keys, a row key and column key.

ClassToInstanceMap

An extension of Map that associates a raw type with an instance of that type.

Collection Implementations

of List

• ImmutableList

of Set

• ImmutableSet
• ImmutableSortedSet
• ContiguousSet (see Range)

of Map

• ImmutableMap
• ImmutableSortedMap
• MapMaker

of BiMap

• ImmutableBiMap
• HashBiMap
• EnumBiMap
• EnumHashBiMap

of Multiset

• ImmutableMultiset
• HashMultiset
• LinkedHashMultiset
• TreeMultiset
• EnumMultiset
• ConcurrentHashMultiset

of Multimap

• ImmutableMultimap
• ImmutableListMultimap
• ImmutableSetMultimap
• ArrayListMultimap
• HashMultimap
• TreeMultimap
• LinkedHashMultimap
• LinkedListMultimap

of Table

• ImmutableTable
• ArrayTable
• HashBasedTable
• TreeBasedTable

of ClassToInstanceMap

• ImmutableClassToInstanceMap
• MutableClassToInstanceMap

Classes of static utility methods

• Collections2
• Iterators
• Iterables
• Lists
• Maps
• Queues
• Sets
• Multisets
• Multimaps
• Tables
• ObjectArrays

Comparison

• Ordering
• ComparisonChain

Abstract implementations

• AbstractIterator
• AbstractSequentialIterator
• ImmutableCollection
• UnmodifiableIterator
• UnmodifiableListIterator

Ranges

• Range
• RangeMap
• DiscreteDomain
• ContiguousSet

Other

• Interner, Interners
• Constraint, Constraints
• MapConstraint, MapConstraints
• MapDifference, SortedMapDifference
• MinMaxPriorityQueue
• PeekingIterator

Forwarding collections

• ForwardingCollection
• ForwardingConcurrentMap
• ForwardingIterator
• ForwardingList
• ForwardingListIterator
• ForwardingListMultimap
• ForwardingMap
• ForwardingMapEntry
• ForwardingMultimap
• ForwardingMultiset
• ForwardingNavigableMap
• ForwardingNavigableSet
• ForwardingObject
• ForwardingQueue
• ForwardingSet
• ForwardingSetMultimap
• ForwardingSortedMap
• ForwardingSortedMultiset
• ForwardingSortedSet
• ForwardingSortedSetMultimap
• ForwardingTable

Interface Summary

Interface	Description
BiMap<K,V>	A bimap (or "bidirectional map") is a map that preserves the uniqueness of its values as well as that of its keys.
ClassToInstanceMap<B>	A map, each entry of which maps a Java raw type to an instance of that type.
Constraint<E>	Deprecated. Use Preconditions for basic checks.
Interner<E>	Provides equivalent behavior to String.intern() for other immutable types.
ListMultimap<K,V>	A Multimap that can hold duplicate key-value pairs and that maintains the insertion ordering of values for a given key.
MapConstraint<K,V>	A constraint on the keys and values that may be added to a Map or Multimap.
MapDifference<K,V>	An object representing the differences between two maps.
MapDifference.ValueDifference<V>	A difference between the mappings from two maps with the same key.
Maps.EntryTransformer<K,V1,V2>	A transformation of the value of a key-value pair, using both key and value as inputs.
Multimap<K,V>	A collection that maps keys to values, similar to Map, but in which each key may be associated with multiple values.
Multiset<E>	A collection that supports order-independent equality, like Set, but may have duplicate elements.
Multiset.Entry<E>	An unmodifiable element-count pair for a multiset.
PeekingIterator<E>	An iterator that supports a one-element lookahead while iterating.
RangeMap<K extends java.lang.Comparable,V>	A mapping from disjoint nonempty ranges to non-null values.
RangeSet<C extends java.lang.Comparable>	A set comprising zero or more nonempty, disconnected ranges of type C.
RowSortedTable<R,C,V>	Interface that extends Table and whose rows are sorted.
SetMultimap<K,V>	A Multimap that cannot hold duplicate key-value pairs.
SortedMapDifference<K,V>	An object representing the differences between two sorted maps.
SortedMultiset<E>	A Multiset which maintains the ordering of its elements, according to either their natural order or an explicit Comparator.
SortedSetMultimap<K,V>	A SetMultimap whose set of values for a given key are kept sorted; that is, they comprise a SortedSet.
Table<R,C,V>	A collection that associates an ordered pair of keys, called a row key and a column key, with a single value.
Table.Cell<R,C,V>	Row key / column key / value triplet corresponding to a mapping in a table.

Class Summary

Class	Description
AbstractIterator<T>	This class provides a skeletal implementation of the Iterator interface, to make this interface easier to implement for certain types of data sources.
AbstractSequentialIterator<T>	This class provides a skeletal implementation of the Iterator interface for sequences whose next element can always be derived from the previous element.
ArrayListMultimap<K,V>	Implementation of Multimap that uses an ArrayList to store the values for a given key.
ArrayTable<R,C,V>	Fixed-size Table implementation backed by a two-dimensional array.
BinaryTreeTraverser<T>	A variant of TreeTraverser for binary trees, providing additional traversals specific to binary trees.
Collections2	Provides static methods for working with Collection instances.
ComparisonChain	A utility for performing a chained comparison statement.
ConcurrentHashMultiset<E>	A multiset that supports concurrent modifications and that provides atomic versions of most Multiset operations (exceptions where noted).
Constraints	Deprecated. Use Preconditions for basic checks.
ContiguousSet<C extends java.lang.Comparable>	A sorted set of contiguous values in a given DiscreteDomain.
DiscreteDomain<C extends java.lang.Comparable>	A descriptor for a discrete Comparable domain such as all Integer instances.
EnumBiMap<K extends java.lang.Enum<K>,V extends java.lang.Enum<V>>	A BiMap backed by two EnumMap instances.
EnumHashBiMap<K extends java.lang.Enum<K>,V>	A BiMap backed by an EnumMap instance for keys-to-values, and a HashMap instance for values-to-keys.
EnumMultiset<E extends java.lang.Enum<E>>	Multiset implementation backed by an EnumMap.
EvictingQueue<E>	A non-blocking queue which automatically evicts elements from the head of the queue when attempting to add new elements onto the queue and it is full.
FluentIterable<E>	FluentIterable provides a rich interface for manipulating Iterable instances in a chained fashion.
ForwardingBlockingDeque<E>	A BlockingDeque which forwards all its method calls to another BlockingDeque.
ForwardingCollection<E>	A collection which forwards all its method calls to another collection.
ForwardingConcurrentMap<K,V>	A concurrent map which forwards all its method calls to another concurrent map.
ForwardingDeque<E>	A deque which forwards all its method calls to another deque.
ForwardingIterator<T>	An iterator which forwards all its method calls to another iterator.
ForwardingList<E>	A list which forwards all its method calls to another list.
ForwardingListIterator<E>	A list iterator which forwards all its method calls to another list iterator.
ForwardingListMultimap<K,V>	A list multimap which forwards all its method calls to another list multimap.
ForwardingMap<K,V>	A map which forwards all its method calls to another map.
ForwardingMapEntry<K,V>	A map entry which forwards all its method calls to another map entry.
ForwardingMultimap<K,V>	A multimap which forwards all its method calls to another multimap.
ForwardingMultiset<E>	A multiset which forwards all its method calls to another multiset.
ForwardingNavigableMap<K,V>	A navigable map which forwards all its method calls to another navigable map.
ForwardingNavigableSet<E>	A navigable set which forwards all its method calls to another navigable set.
ForwardingObject	An abstract base class for implementing the decorator pattern.
ForwardingQueue<E>	A queue which forwards all its method calls to another queue.
ForwardingSet<E>	A set which forwards all its method calls to another set.
ForwardingSetMultimap<K,V>	A set multimap which forwards all its method calls to another set multimap.
ForwardingSortedMap<K,V>	A sorted map which forwards all its method calls to another sorted map.
ForwardingSortedMultiset<E>	A sorted multiset which forwards all its method calls to another sorted multiset.
ForwardingSortedSet<E>	A sorted set which forwards all its method calls to another sorted set.
ForwardingSortedSetMultimap<K,V>	A sorted set multimap which forwards all its method calls to another sorted set multimap.
ForwardingTable<R,C,V>	A table which forwards all its method calls to another table.
GenericMapMaker<K0,V0>	Deprecated. This class existed only to support the generic paramterization necessary for the caching functionality in MapMaker.
HashBasedTable<R,C,V>	Implementation of Table using hash tables.
HashBiMap<K,V>	A BiMap backed by two hash tables.
HashMultimap<K,V>	Implementation of Multimap using hash tables.
HashMultiset<E>	Multiset implementation backed by a HashMap.
ImmutableBiMap<K,V>	An immutable BiMap with reliable user-specified iteration order.
ImmutableBiMap.Builder<K,V>	A builder for creating immutable bimap instances, especially public static final bimaps ("constant bimaps").
ImmutableClassToInstanceMap<B>	A class-to-instance map backed by an ImmutableMap.
ImmutableClassToInstanceMap.Builder<B>	A builder for creating immutable class-to-instance maps.
ImmutableCollection<E>	An immutable collection.
ImmutableCollection.Builder<E>	Abstract base class for builders of ImmutableCollection types.
ImmutableList<E>	A high-performance, immutable, random-access List implementation.
ImmutableList.Builder<E>	A builder for creating immutable list instances, especially public static final lists ("constant lists").
ImmutableListMultimap<K,V>	An immutable ListMultimap with reliable user-specified key and value iteration order.
ImmutableListMultimap.Builder<K,V>	A builder for creating immutable ListMultimap instances, especially public static final multimaps ("constant multimaps").
ImmutableMap<K,V>	An immutable, hash-based Map with reliable user-specified iteration order.
ImmutableMap.Builder<K,V>	A builder for creating immutable map instances, especially public static final maps ("constant maps").
ImmutableMultimap<K,V>	An immutable Multimap.
ImmutableMultimap.Builder<K,V>	A builder for creating immutable multimap instances, especially public static final multimaps ("constant multimaps").
ImmutableMultiset<E>	An immutable hash-based multiset.
ImmutableMultiset.Builder<E>	A builder for creating immutable multiset instances, especially public static final multisets ("constant multisets").
ImmutableRangeMap<K extends java.lang.Comparable<?>,V>	An immutable implementation of RangeMap, supporting all query operations efficiently.
ImmutableRangeMap.Builder<K extends java.lang.Comparable<?>,V>	A builder for immutable range maps.
ImmutableRangeSet<C extends java.lang.Comparable>	An efficient immutable implementation of a RangeSet.
ImmutableRangeSet.Builder<C extends java.lang.Comparable<?>>	A builder for immutable range sets.
ImmutableSet<E>	A high-performance, immutable Set with reliable, user-specified iteration order.
ImmutableSet.Builder<E>	A builder for creating immutable set instances, especially public static final sets ("constant sets").
ImmutableSetMultimap<K,V>	An immutable SetMultimap with reliable user-specified key and value iteration order.
ImmutableSetMultimap.Builder<K,V>	A builder for creating immutable SetMultimap instances, especially public static final multimaps ("constant multimaps").
ImmutableSortedMap<K,V>	An immutable SortedMap.
ImmutableSortedMap.Builder<K,V>	A builder for creating immutable sorted map instances, especially public static final maps ("constant maps").
ImmutableSortedMultiset<E>	An immutable SortedMultiset that stores its elements in a sorted array.
ImmutableSortedMultiset.Builder<E>	A builder for creating immutable multiset instances, especially public static final multisets ("constant multisets").
ImmutableSortedSet<E>	An immutable SortedSet that stores its elements in a sorted array.
ImmutableSortedSet.Builder<E>	A builder for creating immutable sorted set instances, especially public static final sets ("constant sets"), with a given comparator.
ImmutableTable<R,C,V>	An immutable Table with reliable user-specified iteration order.
ImmutableTable.Builder<R,C,V>	A builder for creating immutable table instances, especially public static final tables ("constant tables").
Interners	Contains static methods pertaining to instances of Interner.
Iterables	This class contains static utility methods that operate on or return objects of type Iterable.
Iterators	This class contains static utility methods that operate on or return objects of type Iterator.
LinkedHashMultimap<K,V>	Implementation of Multimap that does not allow duplicate key-value entries and that returns collections whose iterators follow the ordering in which the data was added to the multimap.
LinkedHashMultiset<E>	A Multiset implementation with predictable iteration order.
LinkedListMultimap<K,V>	An implementation of ListMultimap that supports deterministic iteration order for both keys and values.
Lists	Static utility methods pertaining to List instances.
MapConstraints	Factory and utilities pertaining to the MapConstraint interface.
MapMaker	A builder of ConcurrentMap instances having any combination of the following features: keys or values automatically wrapped in weak or soft references notification of evicted (or otherwise removed) entries on-demand computation of values for keys not already present
Maps	Static utility methods pertaining to Map instances (including instances of SortedMap, BiMap, etc.).
MinMaxPriorityQueue<E>	A double-ended priority queue, which provides constant-time access to both its least element and its greatest element, as determined by the queue's specified comparator.
MinMaxPriorityQueue.Builder<B>	The builder class used in creation of min-max priority queues.
Multimaps	Provides static methods acting on or generating a Multimap.
Multisets	Provides static utility methods for creating and working with Multiset instances.
MutableClassToInstanceMap<B>	A mutable class-to-instance map backed by an arbitrary user-provided map.
ObjectArrays	Static utility methods pertaining to object arrays.
Ordering<T>	A comparator, with additional methods to support common operations.
Queues	Static utility methods pertaining to Queue and Deque instances.
Range<C extends java.lang.Comparable>	A range (or "interval") defines the boundaries around a contiguous span of values of some Comparable type; for example, "integers from 1 to 100 inclusive." Note that it is not possible to iterate over these contained values.
Sets	Static utility methods pertaining to Set instances.
Sets.SetView<E>	An unmodifiable view of a set which may be backed by other sets; this view will change as the backing sets do.
Tables	Provides static methods that involve a Table.
TreeBasedTable<R,C,V>	Implementation of Table whose row keys and column keys are ordered by their natural ordering or by supplied comparators.
TreeMultimap<K,V>	Implementation of Multimap whose keys and values are ordered by their natural ordering or by supplied comparators.
TreeMultiset<E>	A multiset which maintains the ordering of its elements, according to either their natural order or an explicit Comparator.
TreeRangeMap<K extends java.lang.Comparable,V>	An implementation of RangeMap based on a TreeMap, supporting all optional operations.
TreeRangeSet<C extends java.lang.Comparable<?>>	An implementation of RangeSet backed by a TreeMap.
TreeTraverser<T>	Views elements of a type T as nodes in a tree, and provides methods to traverse the trees induced by this traverser.
UnmodifiableIterator<E>	An iterator that does not support UnmodifiableIterator.remove().
UnmodifiableListIterator<E>	A list iterator that does not support UnmodifiableIterator.remove(), UnmodifiableListIterator.add(E), or UnmodifiableListIterator.set(E).

Enum Summary

Enum	Description
BoundType	Indicates whether an endpoint of some range is contained in the range itself ("closed") or not ("open").

Exception Summary

Exception	Description
ComputationException	Wraps an exception that occurred during a computation.