net.pwall.util

Class ImmutableMap.KeySet<K,V>

java.lang.Object

net.pwall.util.ImmutableBase<A>

net.pwall.util.ImmutableCollectionBase<ImmutableMapEntry<K,V>,K>

net.pwall.util.ImmutableMap.KeySet<K,V>

Type Parameters:

K - the key type

V - the value type

All Implemented Interfaces:

Iterable<K>, Collection<K>, Set<K>

Enclosing class:

ImmutableMap<K,V>

public static class ImmutableMap.KeySet<K,V>
extends ImmutableCollectionBase<ImmutableMapEntry<K,V>,K>
implements Set<K>

Implementation of the Set interface to provide a view of the keys in the ImmutableMap. It makes use of the same underlying array, but returns only the key portion of the ImmutableMapEntry.

Method Summary

Modifier and Type	Method and Description
boolean	contains(Object o) Test whether the set contains an element equal to the specified object (which may be null).
boolean	equals(Object other) Compares the specified object with this set for equality.
K	get(int index) Get the key at the specified index.
int	hashCode() Returns the hash code value for this set.
Iterator<K>	iterator() Return an Iterator over the set.
Object[]	toArray() Create a copy of the set in an array.
<T> T[]	toArray(T[] a) Return a copy of the set, either in the supplied array (if it fits) or in a new array of the specified type.

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, containsAll, isEmpty, remove, removeAll, retainAll, size, spliterator

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream

Methods inherited from interface java.lang.Iterable

forEach

Method Detail

contains

public boolean contains(Object o)

Test whether the set contains an element equal to the specified object (which may be null).

Specified by:

contains in interface Collection<K>

Specified by:

contains in interface Set<K>

Parameters:

o - the key

Returns:

true if the set contains the object

iterator

public Iterator<K> iterator()

Return an Iterator over the set.

Specified by:

iterator in interface Iterable<K>

Specified by:

iterator in interface Collection<K>

Specified by:

iterator in interface Set<K>

Returns:

the Iterator

toArray

public Object[] toArray()

Create a copy of the set in an array.

Specified by:

toArray in interface Collection<K>

Specified by:

toArray in interface Set<K>

Returns:

a copy of the keys in the active portion of the array

toArray

public <T> T[] toArray(T[] a)

Return a copy of the set, either in the supplied array (if it fits) or in a new array of the specified type.

Specified by:

toArray in interface Collection<K>

Specified by:

toArray in interface Set<K>

Type Parameters:

T - the type of the destination array items

Parameters:

a - the destination array

Returns:

a copy of the keys in the active portion of the map array, in a new array if necessary

Throws:

ArrayStoreException - if the keys in the map can't be stored in the destination array

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<K>

Specified by:

equals in interface Set<K>

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<K>

Specified by:

hashCode in interface Set<K>

Overrides:

hashCode in class Object

Returns:

the hash code value for this set

get

public K get(int index)

Get the key at the specified index. This is not part of the standard Set interface, but it allows iteration over the entries of a map without needing to instantiate an Iterator.
The function does not check the array index because the indexing operation on the array will do that anyway.

Parameters:

index - the index

Returns:

the element at that index

Throws:

IndexOutOfBoundsException - if the index is less than 0 or greater than the length of the list