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java.lang.Objectjava.util.AbstractCollection
java.util.AbstractList
org.apache.commons.collections.list.TreeList
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.
Field Summary |
Fields inherited from class java.util.AbstractList |
modCount |
Constructor Summary | |
TreeList()
Constructs a new empty list. |
|
TreeList(java.util.Collection coll)
Constructs a new empty list that copies the specified list. |
Method Summary | |
void |
add(int index,
java.lang.Object obj)
Adds a new element to the list. |
void |
clear()
Clears the list, removing all entries. |
boolean |
contains(java.lang.Object object)
Searches for the presence of an object in the list. |
java.lang.Object |
get(int index)
Gets the element at the specified index. |
int |
indexOf(java.lang.Object object)
Searches for the index of an object in the list. |
java.util.Iterator |
iterator()
Gets an iterator over the list. |
java.util.ListIterator |
listIterator()
Gets a ListIterator over the list. |
java.util.ListIterator |
listIterator(int fromIndex)
Gets a ListIterator over the list. |
java.lang.Object |
remove(int index)
Removes the element at the specified index. |
java.lang.Object |
set(int index,
java.lang.Object obj)
Sets 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.util.AbstractList |
add, addAll, equals, hashCode, lastIndexOf, removeRange, subList |
Methods inherited from class java.util.AbstractCollection |
addAll, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toString |
Methods inherited from class java.lang.Object |
clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
Methods inherited from interface java.util.List |
addAll, containsAll, isEmpty, remove, removeAll, retainAll, toArray |
Constructor Detail |
public TreeList()
public TreeList(java.util.Collection coll)
coll
- the collection to copy
java.lang.NullPointerException
- if the collection is nullMethod Detail |
public java.lang.Object get(int index)
index
- the index to retrieve
public int size()
public java.util.Iterator iterator()
public java.util.ListIterator listIterator()
public java.util.ListIterator listIterator(int fromIndex)
fromIndex
- the index to start from
public int indexOf(java.lang.Object object)
public boolean contains(java.lang.Object object)
public java.lang.Object[] toArray()
public void add(int index, java.lang.Object obj)
index
- the index to add beforeobj
- the element to addpublic java.lang.Object set(int index, java.lang.Object obj)
index
- the index to setobj
- the object to store at the specified index
java.lang.IndexOutOfBoundsException
- if the index is invalidpublic java.lang.Object remove(int index)
index
- the index to remove
public void clear()
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