Package org.apache.sis.io.wkt

Class SingletonElement

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractSet<Element>

org.apache.sis.io.wkt.SingletonElement

All Implemented Interfaces:

Iterable<Element>, Collection<Element>, Set<Element>

final class SingletonElement
extends AbstractSet<Element>

A mutable set containing either null or a single element. If more than one element is added, only the first one is kept. This is for use with StoredTree.toElements(AbstractParser, Collection, int) in the common case where we expect exactly one element.

Since:

1.1

Version:

1.1

Field Summary

Fields

Modifier and Type	Field	Description
(package private) Element	value	The singleton element, or null if none.

Constructor Summary

Constructors

Constructor	Description
SingletonElement()	Creates an initially empty singleton.

Method Summary

Modifier and Type	Method	Description
boolean	add(Element n)	Adds the given value if this set is empty.
boolean	isEmpty()	Returns true if no value has been specified yet.
Iterator<Element>	iterator()	Returns an iterator over the elements in this set.
int	size()	Returns the number of elements in this set, which cannot be greater than 1.

Methods inherited from class java.util.AbstractSet

equals, hashCode, removeAll

Methods inherited from class java.util.AbstractCollection

addAll, clear, contains, containsAll, remove, retainAll, toArray, toArray, 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

Methods inherited from interface java.lang.Iterable

forEach

Methods inherited from interface java.util.Set

addAll, clear, contains, containsAll, remove, retainAll, spliterator, toArray, toArray

Field Details

value

Element value

The singleton element, or null if none.

Constructor Details

SingletonElement

SingletonElement()

Creates an initially empty singleton.

Method Details

isEmpty

public boolean isEmpty()

Returns true if no value has been specified yet.

Specified by:

isEmpty in interface Collection<Element>

Specified by:

isEmpty in interface Set<Element>

Overrides:

isEmpty in class AbstractCollection<Element>

size

public int size()

Returns the number of elements in this set, which cannot be greater than 1.

Specified by:

size in interface Collection<Element>

Specified by:

size in interface Set<Element>

Specified by:

size in class AbstractCollection<Element>

iterator

public Iterator<Element> iterator()

Returns an iterator over the elements in this set.

Specified by:

iterator in interface Collection<Element>

Specified by:

iterator in interface Iterable<Element>

Specified by:

iterator in interface Set<Element>

Specified by:

iterator in class AbstractCollection<Element>

add

public boolean add(Element n)

Adds the given value if this set is empty.

Specified by:

add in interface Collection<Element>

Specified by:

add in interface Set<Element>

Overrides:

add in class AbstractCollection<Element>