org.apache.commons.collections.set.ListOrderedSet

All Implemented Interfaces:: Serializable, Iterable, Collection, Set

public class ListOrderedSet extends AbstractSerializableSetDecorator implements Set

Decorates another Set to ensure that the order of addition is retained and used by the iterator.

If an object is added to the set for a second time, it will remain in the original position in the iteration. The order can be observed from the set via the iterator or toArray methods.

The ListOrderedSet also has various useful direct methods. These include many from List, such as get(int), remove(int) and indexOf(int). An unmodifiable List view of the set can be obtained via asList().

This class cannot implement the List interface directly as various interface methods (notably equals/hashCode) are incompatable with a set.

This class is Serializable from Commons Collections 3.1.

Since:

Commons Collections 3.0

Version:

$Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $

Author:

Stephen Colebourne, Henning P. Schmiedehausen

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type

Field

Description

protected final List

setOrder

Internal list to hold the sequence of objects

Fields inherited from class org.apache.commons.collections.collection.AbstractCollectionDecorator
collection
Constructor Summary

Constructors

Modifier

Constructor

Description

ListOrderedSet()

Constructs a new empty ListOrderedSet using a HashSet and an ArrayList internally.

protected

ListOrderedSet(Set set)

Constructor that wraps (not copies).

protected

ListOrderedSet(Set set, List list)

Constructor that wraps (not copies) the Set and specifies the list to use.
Method Summary

Modifier and Type

Method

Description

void

add(int index, Object object)

boolean

add(Object object)

boolean

addAll(int index, Collection coll)

boolean

addAll(Collection coll)

List

asList()

Gets an unmodifiable view of the order of the Set.

void

clear()

static ListOrderedSet

decorate(List list)

Factory method to create an ordered set using the supplied list to retain order.

static ListOrderedSet

decorate(Set set)

Factory method to create an ordered set.

static ListOrderedSet

decorate(Set set, List list)

Factory method to create an ordered set specifying the list and set to use.

Object

get(int index)

int

indexOf(Object object)

Iterator

iterator()

Object

remove(int index)

boolean

remove(Object object)

boolean

removeAll(Collection coll)

boolean

retainAll(Collection coll)

Object[]

toArray()

Object[]

toArray(Object[] a)

String

toString()

Uses the underlying List's toString so that order is achieved.

Methods inherited from class org.apache.commons.collections.set.AbstractSetDecorator
getSet

Methods inherited from class org.apache.commons.collections.collection.AbstractCollectionDecorator
contains, containsAll, equals, getCollection, hashCode, isEmpty, size

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
contains, containsAll, equals, hashCode, isEmpty, size, spliterator

Field Details
- setOrder
  
  protected final List setOrder
  
  Internal list to hold the sequence of objects
Constructor Details
- ListOrderedSet
  
  public ListOrderedSet()
  
  Constructs a new empty ListOrderedSet using a HashSet and an ArrayList internally.
  
  Since:
  
  Commons Collections 3.1
- ListOrderedSet
  
  protected ListOrderedSet(Set set)
  
  Constructor that wraps (not copies).
  
  Parameters:
  
  set - the set to decorate, must not be null
  
  Throws:
  
  IllegalArgumentException - if set is null
- ListOrderedSet
  
  protected ListOrderedSet(Set set, List list)
  
  Constructor that wraps (not copies) the Set and specifies the list to use.
  The set and list must both be correctly initialised to the same elements.
  
  Parameters:
  
  set - the set to decorate, must not be null
  
  list - the list to decorate, must not be null
  
  Throws:
  
  IllegalArgumentException - if set or list is null
Method Details
- decorate
  
  public static ListOrderedSet decorate(Set set, List list)
  
  Factory method to create an ordered set specifying the list and set to use.
  The list and set must both be empty.
  
  Parameters:
  
  set - the set to decorate, must be empty and not null
  
  list - the list to decorate, must be empty and not null
  
  Throws:
  
  IllegalArgumentException - if set or list is null
  
  IllegalArgumentException - if either the set or list is not empty
  
  Since:
  
  Commons Collections 3.1
- decorate
  
  public static ListOrderedSet decorate(Set set)
  
  Factory method to create an ordered set.
  An ArrayList is used to retain order.
  
  Parameters:
  
  set - the set to decorate, must not be null
  
  Throws:
  
  IllegalArgumentException - if set is null
- decorate
  
  public static ListOrderedSet decorate(List list)
  
  Factory method to create an ordered set using the supplied list to retain order.
  A HashSet is used for the set behaviour.
  NOTE: If the list contains duplicates, the duplicates are removed, altering the specified list.
  
  Parameters:
  
  list - the list to decorate, must not be null
  
  Throws:
  
  IllegalArgumentException - if list is null
- asList
  
  public List asList()
  
  Gets an unmodifiable view of the order of the Set.
  
  Returns:
  
  an unmodifiable list view
- clear
  
  public void clear()
  
  Specified by:
  
  clear in interface Collection
  
  Specified by:
  
  clear in interface Set
  
  Overrides:
  
  clear in class AbstractCollectionDecorator
- iterator
  
  public Iterator iterator()
  
  Specified by:
  
  iterator in interface Collection
  
  Specified by:
  
  iterator in interface Iterable
  
  Specified by:
  
  iterator in interface Set
  
  Overrides:
  
  iterator in class AbstractCollectionDecorator
- add
  
  public boolean add(Object object)
  
  Specified by:
  
  add in interface Collection
  
  Specified by:
  
  add in interface Set
  
  Overrides:
  
  add in class AbstractCollectionDecorator
- addAll
  
  public boolean addAll(Collection coll)
  
  Specified by:
  
  addAll in interface Collection
  
  Specified by:
  
  addAll in interface Set
  
  Overrides:
  
  addAll in class AbstractCollectionDecorator
- remove
  
  public boolean remove(Object object)
  
  Specified by:
  
  remove in interface Collection
  
  Specified by:
  
  remove in interface Set
  
  Overrides:
  
  remove in class AbstractCollectionDecorator
- removeAll
  
  public boolean removeAll(Collection coll)
  
  Specified by:
  
  removeAll in interface Collection
  
  Specified by:
  
  removeAll in interface Set
  
  Overrides:
  
  removeAll in class AbstractCollectionDecorator
- retainAll
  
  public boolean retainAll(Collection coll)
  
  Specified by:
  
  retainAll in interface Collection
  
  Specified by:
  
  retainAll in interface Set
  
  Overrides:
  
  retainAll in class AbstractCollectionDecorator
- toArray
  
  public Object[] toArray()
  
  Specified by:
  
  toArray in interface Collection
  
  Specified by:
  
  toArray in interface Set
  
  Overrides:
  
  toArray in class AbstractCollectionDecorator
- toArray
  
  public Object[] toArray(Object[] a)
  
  Specified by:
  
  toArray in interface Collection
  
  Specified by:
  
  toArray in interface Set
  
  Overrides:
  
  toArray in class AbstractCollectionDecorator
- get
  
  public Object get(int index)
- indexOf
  
  public int indexOf(Object object)
- add
  
  public void add(int index, Object object)
- addAll
  
  public boolean addAll(int index, Collection coll)
- remove
  
  public Object remove(int index)
- toString
  
  public String toString()
  
  Uses the underlying List's toString so that order is achieved. This means that the decorated Set's toString is not used, so any custom toStrings will be ignored.
  
  Overrides:
  
  toString in class AbstractCollectionDecorator

Class ListOrderedSet

Field Summary

Fields inherited from class org.apache.commons.collections.collection.AbstractCollectionDecorator

Constructor Summary

Method Summary

Methods inherited from class org.apache.commons.collections.set.AbstractSetDecorator

Methods inherited from class org.apache.commons.collections.collection.AbstractCollectionDecorator

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

Field Details

setOrder

Constructor Details

ListOrderedSet

ListOrderedSet

ListOrderedSet

Method Details

decorate

decorate

decorate

asList

clear

iterator

add

addAll

remove

removeAll

retainAll

toArray

toArray

get

indexOf

add

addAll

remove

toString