org.magicwerk.brownies.collections.helper

Class RangeList<E>

java.lang.Object

org.magicwerk.brownies.collections.helper.RangeList<E>

public class RangeList<E>
extends java.lang.Object

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 slightly more memory.

Since:

3.1

Version:

$Id: TreeList.java 1533984 2013-10-20 21:12:51Z tn $

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	RangeList.AVLNode<E> Implements an AVLNode which keeps the offset updated.

Field Summary

Fields

Modifier and Type	Field and Description
RangeList.AVLNode<E>	root The root node in the AVL tree

Constructor Summary

Constructors

Constructor and Description
RangeList() Constructs a new empty list.
RangeList(java.util.Collection<? extends E> coll) Constructs a new empty list that copies the specified collection.

Method Summary

Methods

Modifier and Type	Method and Description
RangeList.AVLNode<E>	access(int index, int modify, int[] endIndex)
void	add(int index, E obj) Adds a new element to the list.
void	clear() Clears the list, removing all entries.
RangeList.AVLNode<E>	getIn(int index, int[] endIndex) Gets the element at the specified index.
void	remove(int index) Removes the element at the specified index.
int	size() Gets the current size of the list.
java.lang.Object[]	toArray() Converts the list into an array.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

root

public RangeList.AVLNode<E> root

The root node in the AVL tree

Constructor Detail

RangeList

public RangeList()

Constructs a new empty list.

RangeList

public RangeList(java.util.Collection<? extends E> coll)

Constructs a new empty list that copies the specified collection.

Parameters:

coll - the collection to copy

Throws:

java.lang.NullPointerException - if the collection is null

Method Detail

getIn

public RangeList.AVLNode<E> getIn(int index,
                         int[] endIndex)

Gets the element at the specified index.

Parameters:

index - the index to retrieve

Returns:

the element at the specified index

access

public RangeList.AVLNode<E> access(int index,
                          int modify,
                          int[] endIndex)

size

public int size()

Gets the current size of the list.

Returns:

the current size

toArray

public java.lang.Object[] toArray()

Converts the list into an array.

Returns:

the list as an array

add

public void add(int index,
       E obj)

Adds a new element to the list.

Parameters:

index - the index to add before

obj - the element to add

remove

public void remove(int index)

Removes the element at the specified index.

Parameters:

index - the index to remove

clear

public void clear()

Clears the list, removing all entries.