com.google.common.collect

Class Sets.SetView<E>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractSet<E>

com.google.common.collect.Sets.SetView<E>

All Implemented Interfaces:

java.lang.Iterable<E>, java.util.Collection<E>, java.util.Set<E>

Enclosing class:

Sets

public abstract static class Sets.SetView<E>
extends java.util.AbstractSet<E>

An unmodifiable view of a set which may be backed by other sets; this view will change as the backing sets do. Contains methods to copy the data into a new set which will then remain stable. There is usually no reason to retain a reference of type SetView; typically, you either use it as a plain Set, or immediately invoke immutableCopy() or copyInto(S) and forget the SetView itself.

Since:

2.0

Constructor Summary

Constructors

Modifier	Constructor and Description
private	SetView()

Method Summary

Modifier and Type	Method and Description
<S extends java.util.Set<E>> S	copyInto(S set) Copies the current contents of this set view into an existing set.
ImmutableSet<E>	immutableCopy() Returns an immutable copy of the current contents of this set view.
abstract UnmodifiableIterator<E>	iterator() Scope the return type to UnmodifiableIterator to ensure this is an unmodifiable view.

Methods inherited from class java.util.AbstractSet

equals, hashCode, removeAll

Methods inherited from class java.util.AbstractCollection

add, addAll, clear, contains, containsAll, isEmpty, remove, retainAll, size, toArray, toArray, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Set

add, addAll, clear, contains, containsAll, isEmpty, remove, retainAll, size, spliterator, toArray, toArray

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream

Methods inherited from interface java.lang.Iterable

forEach

Constructor Detail

SetView

private SetView()

Method Detail

immutableCopy

public ImmutableSet<E> immutableCopy()

Returns an immutable copy of the current contents of this set view. Does not support null elements.

Warning: this may have unexpected results if a backing set of this view uses a nonstandard notion of equivalence, for example if it is a TreeSet using a comparator that is inconsistent with Object.equals(Object).

copyInto

public <S extends java.util.Set<E>> S copyInto(S set)

Copies the current contents of this set view into an existing set. This method has equivalent behavior to set.addAll(this), assuming that all the sets involved are based on the same notion of equivalence.

Returns:

a reference to set, for convenience

iterator

public abstract UnmodifiableIterator<E> iterator()

Scope the return type to UnmodifiableIterator to ensure this is an unmodifiable view.

Specified by:

iterator in interface java.lang.Iterable<E>

Specified by:

iterator in interface java.util.Collection<E>

Specified by:

iterator in interface java.util.Set<E>

Specified by:

iterator in class java.util.AbstractCollection<E>

Since:

20.0 (present with return type Iterator since 2.0)