net.pwall.util

Class ImmutableSet<T>

java.lang.Object

net.pwall.util.ImmutableBase<A>

net.pwall.util.ImmutableCollectionBase<T,T>

net.pwall.util.ImmutableCollection<T>

net.pwall.util.ImmutableSet<T>

Type Parameters:

T - the set element type

All Implemented Interfaces:

Iterable<T>, Collection<T>, Set<T>

public class ImmutableSet<T>
extends ImmutableCollection<T>
implements Set<T>

Immutable implementation of Set.

Author:

Peter Wall

Constructor Summary

Constructors

Constructor and Description
ImmutableSet(Set<T> set) Construct an ImmutableSet from another Set (helps with deserializing).
ImmutableSet(T[] array) Construct an ImmutableSet with the given array (using the entire array).
ImmutableSet(T[] array, int length) Construct an ImmutableSet with the given array and length.

Method Summary

Modifier and Type	Method and Description
static <TT> ImmutableSet<TT>	emptySet() Get an empty ImmutableSet.
boolean	equals(Object other) Compares the specified object with this set for equality.
int	hashCode() Returns the hash code value for this set.
static <TT> ImmutableSet<TT>	setOf(TT[] array) Get an ImmutableSet using the supplied array.
static <TT> ImmutableSet<TT>	setOf(TT[] array, int length) Get an ImmutableSet using the supplied array.

Methods inherited from class net.pwall.util.ImmutableCollection

contains, contains, get, get, iterator, toArray, toArray

Methods inherited from class net.pwall.util.ImmutableCollectionBase

add, addAll, containsAll, remove, removeAll, retainAll, toString

Methods inherited from class net.pwall.util.ImmutableBase

clear, isEmpty, size

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, iterator, remove, removeAll, 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

ImmutableSet

public ImmutableSet(T[] array,
                    int length)

Construct an ImmutableSet with the given array and length.
**IMPORTANT – the set is immutable only if the array is not subsequently modified.**

Parameters:

array - the array

length - the length (the number of array items to be considered part of the set)

Throws:

IndexOutOfBoundsException - if the length is less than 0 or greater than the array length

ImmutableSet

public ImmutableSet(T[] array)

Construct an ImmutableSet with the given array (using the entire array).
**IMPORTANT – the set is immutable only if the array is not subsequently modified.**

Parameters:

array - the array

ImmutableSet

public ImmutableSet(Set<T> set)

Construct an ImmutableSet from another Set (helps with deserializing).

Parameters:

set - the other Set

Method Detail

equals

public boolean equals(Object other)

Compares the specified object with this set for equality. Returns true if the specified object is also a set, the two sets have the same size, and every member of the specified set is contained in this set (or equivalently, every member of this set is contained in the specified set). This definition ensures that the equals method works properly across different implementations of the set interface.

Specified by:

equals in interface Collection<T>

Specified by:

equals in interface Set<T>

Overrides:

equals in class Object

Parameters:

other - object to be compared for equality with this set

Returns:

true if the specified object is equal to this set

hashCode

public int hashCode()

Returns the hash code value for this set. The hash code of a set is defined to be the sum of the hash codes of the elements in the set, where the hash code of a null element is defined to be zero. This ensures that s1.equals(s2) implies that s1.hashCode() == s2.hashCode() for any two sets s1 and s2, as required by the general contract of Object.hashCode().

Specified by:

hashCode in interface Collection<T>

Specified by:

hashCode in interface Set<T>

Overrides:

hashCode in class Object

Returns:

the hash code value for this set

emptySet

public static <TT> ImmutableSet<TT> emptySet()

Get an empty ImmutableSet. This avoids a memory allocation if the set is empty.

Type Parameters:

TT - the element type

Returns:

an empty set

setOf

public static <TT> ImmutableSet<TT> setOf(TT[] array)

Get an ImmutableSet using the supplied array. If the array length is zero, the empty set is returned.

Type Parameters:

TT - the element type

Parameters:

array - the array

Returns:

the set

setOf

public static <TT> ImmutableSet<TT> setOf(TT[] array,
                                          int length)

Get an ImmutableSet using the supplied array. If the array length is zero, the empty set is returned.

Type Parameters:

TT - the element type

Parameters:

array - the array

length - the length (the number of array items to be considered part of the set)

Returns:

the set