org.apache.commons.collections.list
Class TreeList
AbstractList
org.apache.commons.collections.list.TreeList
public class TreeList
extends AbstractList
A
List
implementation that is optimised for fast insertions and
removals at any index in the list.
This list implementation utilises a tree structure internally to ensure that
all insertions and removals are O(log n). This provides much faster performance
than both an
ArrayList
and a
LinkedList
where elements
are inserted and removed repeatedly from anywhere in the list.
The following relative performance statistics are indicative of this class:
get add insert iterate remove
TreeList 3 5 1 2 1
ArrayList 1 1 40 1 40
LinkedList 5800 1 350 2 325
ArrayList
is a good general purpose list implementation.
It is faster than
TreeList
for most operations except inserting
and removing in the middle of the list.
ArrayList
also uses less
memory as
TreeList
uses one object per entry.
LinkedList
is rarely a good choice of implementation.
TreeList
is almost always a good replacement for it, although it
does use sligtly more memory.
$Revision: 1.3 $ $Date: 2004/05/26 21:56:05 $- Joerg Schmuecker
- Stephen Colebourne
TreeList() - Constructs a new empty list.
|
TreeList(Collection coll) - Constructs a new empty list that copies the specified list.
|
void | add(int index, Object obj) - Adds a new element to the list.
|
void | clear() - Clears the list, removing all entries.
|
boolean | contains(Object object) - Searches for the presence of an object in the list.
|
Object | get(int index) - Gets the element at the specified index.
|
int | indexOf(Object object) - Searches for the index of an object in the list.
|
Iterator | iterator() - Gets an iterator over the list.
|
ListIterator | listIterator() - Gets a ListIterator over the list.
|
ListIterator | listIterator(int fromIndex) - Gets a ListIterator over the list.
|
Object | remove(int index) - Removes the element at the specified index.
|
Object | set(int index, Object obj) - Sets the element at the specified index.
|
int | size() - Gets the current size of the list.
|
Object[] | toArray() - Converts the list into an array.
|
TreeList
public TreeList()
Constructs a new empty list.
TreeList
public TreeList(Collection coll)
Constructs a new empty list that copies the specified list.
coll
- the collection to copy
add
public void add(int index,
Object obj)
Adds a new element to the list.
index
- the index to add beforeobj
- the element to add
clear
public void clear()
Clears the list, removing all entries.
contains
public boolean contains(Object object)
Searches for the presence of an object in the list.
- true if the object is found
get
public Object get(int index)
Gets the element at the specified index.
index
- the index to retrieve
- the element at the specified index
indexOf
public int indexOf(Object object)
Searches for the index of an object in the list.
- the index of the object, -1 if not found
iterator
public Iterator iterator()
Gets an iterator over the list.
- an iterator over the list
listIterator
public ListIterator listIterator()
Gets a ListIterator over the list.
listIterator
public ListIterator listIterator(int fromIndex)
Gets a ListIterator over the list.
fromIndex
- the index to start from
remove
public Object remove(int index)
Removes the element at the specified index.
index
- the index to remove
- the previous object at that index
set
public Object set(int index,
Object obj)
Sets the element at the specified index.
index
- the index to setobj
- the object to store at the specified index
- the previous object at that index
size
public int size()
Gets the current size of the list.
toArray
public Object[] toArray()
Converts the list into an array.
Copyright © 2001-2006 Apache Software Foundation. All Rights Reserved.