java.lang.Object
- java.util.AbstractCollection<E>
- - com.google.common.collect.ImmutableCollection<E>
  - - com.google.common.collect.ImmutableSet<E>

All Implemented Interfaces:

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

Direct Known Subclasses:

ImmutableSortedSet
```
@GwtCompatible(serializable=true,
               emulated=true)
public abstract class ImmutableSet<E>
extends ImmutableCollection<E>
implements java.util.Set<E>
```
A high-performance, immutable Set with reliable, user-specified iteration order. Does not permit null elements.
Unlike Collections.unmodifiableSet(java.util.Set<? extends T>), which is a view of a separate collection that can still change, an instance of this class contains its own private data and will never change. This class is convenient for public static final sets ("constant sets") and also lets you easily make a "defensive copy" of a set provided to your class by a caller.
Warning: Like most sets, an ImmutableSet will not function correctly if an element is modified after being placed in the set. For this reason, and to avoid general confusion, it is strongly recommended to place only immutable objects into this collection.
This class has been observed to perform significantly better than HashSet for objects with very fast Object.hashCode() implementations (as a well-behaved immutable object should). While this class's factory methods create hash-based instances, the ImmutableSortedSet subclass performs binary searches instead.
Note: Although this class is not final, it cannot be subclassed outside its package as it has no public or protected constructors. Thus, instances of this type are guaranteed to be immutable.
See the Guava User Guide article on immutable collections.

Since:

2.0 (imported from Google Collections Library)

See Also:

ImmutableList, ImmutableMap, Serialized Form

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`static class`	`ImmutableSet.Builder<E>`	A builder for creating immutable set instances, especially `public static final` sets ("constant sets").

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method	Description
`static <E> ImmutableSet.Builder<E>`	`builder()`	Returns a new builder.
`static <E> ImmutableSet<E>`	`copyOf(E[] elements)`	Returns an immutable set containing the given elements, in order.
`static <E> ImmutableSet<E>`	`copyOf(java.lang.Iterable<? extends E> elements)`	Returns an immutable set containing the given elements, in order.
`static <E> ImmutableSet<E>`	`copyOf(java.util.Collection<? extends E> elements)`	Returns an immutable set containing the given elements, in order.
`static <E> ImmutableSet<E>`	`copyOf(java.util.Iterator<? extends E> elements)`	Returns an immutable set containing the given elements, in order.
`boolean`	`equals(java.lang.Object object)`
`int`	`hashCode()`
`abstract UnmodifiableIterator<E>`	`iterator()`	Returns an unmodifiable iterator across the elements in this collection.
`static <E> ImmutableSet<E>`	`of()`	Returns the empty immutable set.
`static <E> ImmutableSet<E>`	`of(E element)`	Returns an immutable set containing a single element.
`static <E> ImmutableSet<E>`	`of(E e1, E e2)`	Returns an immutable set containing the given elements, in order.
`static <E> ImmutableSet<E>`	`of(E e1, E e2, E e3)`	Returns an immutable set containing the given elements, in order.
`static <E> ImmutableSet<E>`	`of(E e1, E e2, E e3, E e4)`	Returns an immutable set containing the given elements, in order.
`static <E> ImmutableSet<E>`	`of(E e1, E e2, E e3, E e4, E e5)`	Returns an immutable set containing the given elements, in order.
`static <E> ImmutableSet<E>`	`of(E e1, E e2, E e3, E e4, E e5, E e6, E... others)`	Returns an immutable set containing the given elements, in order.

Methods inherited from class com.google.common.collect.ImmutableCollection
add, addAll, asList, clear, contains, remove, removeAll, retainAll, toArray, toArray

Methods inherited from class java.util.AbstractCollection
containsAll, isEmpty, size, toString

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Collection
parallelStream, removeIf, stream, toArray

Methods inherited from interface java.lang.Iterable
forEach

Methods inherited from interface java.util.Set
add, addAll, clear, contains, containsAll, isEmpty, remove, removeAll, retainAll, size, spliterator, toArray, toArray

- Method Detail
  - of
```
public static <E> ImmutableSet<E> of()
```
    Returns the empty immutable set. This set behaves and performs comparably to Collections.emptySet(), and is preferable mainly for consistency and maintainability of your code.
  - of
```
public static <E> ImmutableSet<E> of(E element)
```
    Returns an immutable set containing a single element. This set behaves and performs comparably to Collections.singleton(T), but will not accept a null element. It is preferable mainly for consistency and maintainability of your code.
  - of
```
public static <E> ImmutableSet<E> of(E e1,
                                     E e2)
```
    Returns an immutable set containing the given elements, in order. Repeated occurrences of an element (according to Object.equals(java.lang.Object)) after the first are ignored.
    
    Throws:
    
    java.lang.NullPointerException - if any element is null
  - of
```
public static <E> ImmutableSet<E> of(E e1,
                                     E e2,
                                     E e3)
```
    Returns an immutable set containing the given elements, in order. Repeated occurrences of an element (according to Object.equals(java.lang.Object)) after the first are ignored.
    
    Throws:
    
    java.lang.NullPointerException - if any element is null
  - of
```
public static <E> ImmutableSet<E> of(E e1,
                                     E e2,
                                     E e3,
                                     E e4)
```
    Returns an immutable set containing the given elements, in order. Repeated occurrences of an element (according to Object.equals(java.lang.Object)) after the first are ignored.
    
    Throws:
    
    java.lang.NullPointerException - if any element is null
  - of
```
public static <E> ImmutableSet<E> of(E e1,
                                     E e2,
                                     E e3,
                                     E e4,
                                     E e5)
```
    Returns an immutable set containing the given elements, in order. Repeated occurrences of an element (according to Object.equals(java.lang.Object)) after the first are ignored.
    
    Throws:
    
    java.lang.NullPointerException - if any element is null
  - of
```
public static <E> ImmutableSet<E> of(E e1,
                                     E e2,
                                     E e3,
                                     E e4,
                                     E e5,
                                     E e6,
                                     E... others)
```
    Returns an immutable set containing the given elements, in order. Repeated occurrences of an element (according to Object.equals(java.lang.Object)) after the first are ignored.
    
    Throws:
    
    java.lang.NullPointerException - if any element is null
    
    Since:
    
    3.0 (source-compatible since 2.0)
  - copyOf
```
public static <E> ImmutableSet<E> copyOf(E[] elements)
```
    Returns an immutable set containing the given elements, in order. Repeated occurrences of an element (according to Object.equals(java.lang.Object)) after the first are ignored.
    
    Throws:
    
    java.lang.NullPointerException - if any of elements is null
    
    Since:
    
    3.0
  - copyOf
```
public static <E> ImmutableSet<E> copyOf(java.lang.Iterable<? extends E> elements)
```
    Returns an immutable set containing the given elements, in order. Repeated occurrences of an element (according to Object.equals(java.lang.Object)) after the first are ignored. This method iterates over elements at most once.
    Note that if s is a Set<String>, then ImmutableSet.copyOf(s) returns an ImmutableSet<String> containing each of the strings in s, while ImmutableSet.of(s) returns a ImmutableSet<Set<String>> containing one element (the given set itself).
    Despite the method name, this method attempts to avoid actually copying the data when it is safe to do so. The exact circumstances under which a copy will or will not be performed are undocumented and subject to change.
    
    Throws:
    
    java.lang.NullPointerException - if any of elements is null
  - copyOf
```
public static <E> ImmutableSet<E> copyOf(java.util.Iterator<? extends E> elements)
```
    Returns an immutable set containing the given elements, in order. Repeated occurrences of an element (according to Object.equals(java.lang.Object)) after the first are ignored.
    
    Throws:
    
    java.lang.NullPointerException - if any of elements is null
  - copyOf
```
public static <E> ImmutableSet<E> copyOf(java.util.Collection<? extends E> elements)
```
    Returns an immutable set containing the given elements, in order. Repeated occurrences of an element (according to Object.equals(java.lang.Object)) after the first are ignored. This method iterates over elements at most once.
    Note that if s is a Set<String>, then ImmutableSet.copyOf(s) returns an ImmutableSet<String> containing each of the strings in s, while ImmutableSet.of(s) returns a ImmutableSet<Set<String>> containing one element (the given set itself).
    Note: Despite what the method name suggests, copyOf will return constant-space views, rather than linear-space copies, of some inputs known to be immutable. For some other immutable inputs, such as key sets of an ImmutableMap, it still performs a copy in order to avoid holding references to the values of the map. The heuristics used in this decision are undocumented and subject to change except that:
    
    A full copy will be done of any ImmutableSortedSet.
    
    ImmutableSet.copyOf() is idempotent with respect to pointer equality.
    
    This method is safe to use even when elements is a synchronized or concurrent collection that is currently being modified by another thread.
    Throws:
    
    java.lang.NullPointerException - if any of elements is null
    
    Since:
    
    7.0 (source-compatible since 2.0)
  - equals
```
public boolean equals(@Nullable
                      java.lang.Object object)
```
    Specified by:
    
    equals in interface java.util.Collection<E>
    
    Specified by:
    
    equals in interface java.util.Set<E>
    
    Overrides:
    
    equals in class java.lang.Object
  - hashCode
```
public int hashCode()
```
    Specified by:
    
    hashCode in interface java.util.Collection<E>
    
    Specified by:
    
    hashCode in interface java.util.Set<E>
    
    Overrides:
    
    hashCode in class java.lang.Object
  - iterator
```
public abstract UnmodifiableIterator<E> iterator()
```
    Description copied from class: ImmutableCollection
    
    Returns an unmodifiable iterator across the elements in this collection.
    
    Specified by:
    
    iterator in interface java.util.Collection<E>
    
    Specified by:
    
    iterator in interface java.lang.Iterable<E>
    
    Specified by:
    
    iterator in interface java.util.Set<E>
    
    Specified by:
    
    iterator in class ImmutableCollection<E>
  - builder
```
public static <E> ImmutableSet.Builder<E> builder()
```
    Returns a new builder. The generated builder is equivalent to the builder created by the ImmutableSet.Builder constructor.

Class ImmutableSet<E>

Nested Class Summary

Method Summary

Methods inherited from class com.google.common.collect.ImmutableCollection

Methods inherited from class java.util.AbstractCollection

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Collection

Methods inherited from interface java.lang.Iterable

Methods inherited from interface java.util.Set

Method Detail

of

of

of

of

of

of

of

copyOf

copyOf

copyOf

copyOf

equals

hashCode

iterator

builder