Class LinkedHashSet<E>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractSet<E>

java.util.HashSet<E>

java.util.LinkedHashSet<E>

All Implemented Interfaces:

Iterable<E>, Collection<E>, Set<E>

public class LinkedHashSet<E>
extends HashSet<E>
implements Set<E>

LinkedHashSet is a variant of HashSet. Its entries are kept in a doubly-linked list. The iteration order is the order in which entries were inserted.

Null elements are allowed, and all the optional Set operations are supported.

Like HashSet, LinkedHashSet is not thread safe, so access by multiple threads must be synchronized by an external mechanism such as Collections.synchronizedSet(Set).

Since:

1.4

Constructor Summary

Constructors

Constructor	Description
LinkedHashSet()	Constructs a new empty instance of LinkedHashSet.
LinkedHashSet(int capacity)	Constructs a new instance of LinkedHashSet with the specified capacity.
LinkedHashSet(int capacity, float loadFactor)	Constructs a new instance of LinkedHashSet with the specified capacity and load factor.
LinkedHashSet(Collection<? extends E> collection)	Constructs a new instance of LinkedHashSet containing the unique elements in the specified collection.

Method Summary

Methods inherited from class HashSet

add, clear, contains, isEmpty, iterator, remove, size

Modifier and Type	Method	Description
boolean	add(E object)	Adds the specified object to this HashSet if not already present.
void	clear()	Removes all elements from this HashSet, leaving it empty.
boolean	contains(Object object)	Searches this HashSet for the specified object.
boolean	isEmpty()	Returns true if this HashSet has no elements, false otherwise.
Iterator<E>	iterator()	Returns an Iterator on the elements of this HashSet.
boolean	remove(Object object)	Removes the specified object from this HashSet.
int	size()	Returns the number of elements in this HashSet.

Methods inherited from class AbstractSet

equals, hashCode, removeAll

Modifier and Type	Method	Description
boolean	equals(Object object)	Compares the specified object to this Set and returns true if they are equal.
int	hashCode()	Returns the hash code for this set.
boolean	removeAll(Collection<?> collection)	Removes all occurrences in this collection which are contained in the specified collection.

Methods inherited from class AbstractCollection

addAll, containsAll, retainAll, toArray, toArray, toString

Modifier and Type	Method	Description
boolean	addAll(Collection<? extends E> collection)	Attempts to add all of the objects contained in collection to the contents of this Collection (optional).
boolean	containsAll(Collection<?> collection)	Tests whether this Collection contains all objects contained in the specified Collection.
boolean	retainAll(Collection<?> collection)	Removes all objects from this Collection that are not also found in the Collection passed (optional).
Object[]	toArray()	Returns a new array containing all elements contained in this ArrayList.
<T> T[]	toArray(T[] contents)	Returns an array containing all elements contained in this ArrayList.
String	toString()	Returns the string representation of this Collection.

Methods inherited from class Object

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

Modifier and Type	Method	Description
protected Object	clone()
final Class	getClass()	Returns the runtime class of an object.
final void	notify()	Wakes up a single thread that is waiting on this object's monitor.
final void	notifyAll()	Wakes up all threads that are waiting on this object's monitor.
final void	wait()	Causes current thread to wait until another thread invokes the method or the method for this object.
final void	wait(long timeout)	Causes current thread to wait until either another thread invokes the method or the method for this object, or a specified amount of time has elapsed.
final void	wait(long timeout, int nanos)	Causes current thread to wait until another thread invokes the method or the method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.

Methods inherited from interface Set

addAll, containsAll, retainAll, toArray, toArray

Modifier and Type	Method	Description
boolean	addAll(Collection<? extends E> collection)	Adds the objects in the specified collection which do not exist yet in this set.
boolean	containsAll(Collection<?> collection)	Searches this set for all objects in the specified collection.
boolean	retainAll(Collection<?> collection)	Removes all objects from this set that are not contained in the specified collection.
Object[]	toArray()	Returns an array containing all elements contained in this set.
<T> T[]	toArray(T[] array)	Returns an array containing all elements contained in this set.

Constructor Details

LinkedHashSet

public LinkedHashSet()

Constructs a new empty instance of LinkedHashSet.

LinkedHashSet

public LinkedHashSet(int capacity)

Constructs a new instance of LinkedHashSet with the specified capacity.

Parameters:

capacity - the initial capacity of this LinkedHashSet.

LinkedHashSet

public LinkedHashSet(int capacity,
 float loadFactor)

Constructs a new instance of LinkedHashSet with the specified capacity and load factor.

Parameters:

capacity - the initial capacity.

loadFactor - the initial load factor.

LinkedHashSet

public LinkedHashSet(Collection<? extends E> collection)

Constructs a new instance of LinkedHashSet containing the unique elements in the specified collection.

Parameters:

collection - the collection of elements to add.