org.apache.commons.collections.list
public class TreeList extends AbstractList
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.
Since: Commons Collections 3.1
Version: $Revision: 370952 $ $Date: 2006-01-21 01:49:21 +0000 (Sat, 21 Jan 2006) $
Constructor Summary | |
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TreeList()
Constructs a new empty list. | |
TreeList(Collection coll)
Constructs a new empty list that copies the specified list.
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Method Summary | |
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void | add(int index, Object obj)
Adds a new element to the list.
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void | clear()
Clears the list, removing all entries. |
boolean | contains(Object object)
Searches for the presence of an object in the list.
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Object | get(int index)
Gets the element at the specified index.
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int | indexOf(Object object)
Searches for the index of an object in the list.
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Iterator | iterator()
Gets an iterator over the list.
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ListIterator | listIterator()
Gets a ListIterator over the list.
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ListIterator | listIterator(int fromIndex)
Gets a ListIterator over the list.
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Object | remove(int index)
Removes the element at the specified index.
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Object | set(int index, Object obj)
Sets the element at the specified index.
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int | size()
Gets the current size of the list.
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Object[] | toArray()
Converts the list into an array.
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Parameters: coll the collection to copy
Throws: NullPointerException if the collection is null
Parameters: index the index to add before obj the element to add
Returns: true if the object is found
Parameters: index the index to retrieve
Returns: the element at the specified index
Returns: the index of the object, -1 if not found
Returns: an iterator over the list
Returns: the new iterator
Parameters: fromIndex the index to start from
Returns: the new iterator
Parameters: index the index to remove
Returns: the previous object at that index
Parameters: index the index to set obj the object to store at the specified index
Returns: the previous object at that index
Throws: IndexOutOfBoundsException if the index is invalid
Returns: the current size
Returns: the list as an array