loci.poi.util

Class BinaryTree

java.lang.Object

java.util.AbstractMap

loci.poi.util.BinaryTree

All Implemented Interfaces:

Map

public final class BinaryTree
extends AbstractMap

Red-Black tree-based implementation of Map. This class guarantees that the map will be in both ascending key order and ascending value order, sorted according to the natural order for the key's and value's classes.

This Map is intended for applications that need to be able to look up a key-value pairing by either key or value, and need to do so with equal efficiency.

While that goal could be accomplished by taking a pair of TreeMaps and redirecting requests to the appropriate TreeMap (e.g., containsKey would be directed to the TreeMap that maps values to keys, containsValue would be directed to the TreeMap that maps keys to values), there are problems with that implementation, particularly when trying to keep the two TreeMaps synchronized with each other. And if the data contained in the TreeMaps is large, the cost of redundant storage becomes significant.

This solution keeps the data properly synchronized and minimizes the data storage. The red-black algorithm is based on TreeMap's, but has been modified to simultaneously map a tree node by key and by value. This doubles the cost of put operations (but so does using two TreeMaps), and nearly doubles the cost of remove operations (there is a savings in that the lookup of the node to be removed only has to be performed once). And since only one node contains the key and value, storage is significantly less than that required by two TreeMaps.

There are some limitations placed on data kept in this Map. The biggest one is this:

When performing a put operation, neither the key nor the value may already exist in the Map. In the java.util Map implementations (HashMap, TreeMap), you can perform a put with an already mapped key, and neither cares about duplicate values at all ... but this implementation's put method with throw an IllegalArgumentException if either the key or the value is already in the Map.

Obviously, that same restriction (and consequence of failing to heed that restriction) applies to the putAll method.

The Map.Entry instances returned by the appropriate methods will not allow setValue() and will throw an UnsupportedOperationException on attempts to call that method.

New methods are added to take advantage of the fact that values are kept sorted independently of their keys:

Object getKeyForValue(Object value) is the opposite of get; it takes a value and returns its key, if any.

Object removeValue(Object value) finds and removes the specified value and returns the now un-used key.

Set entrySetByValue() returns the Map.Entry's in a Set whose iterator will iterate over the Map.Entry's in ascending order by their corresponding values.

Set keySetByValue() returns the keys in a Set whose iterator will iterate over the keys in ascending order by their corresponding values.

Collection valuesByValue() returns the values in a Collection whose iterator will iterate over the values in ascending order.

Author:

Marc Johnson (mjohnson at apache dot org)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	BinaryTree.BinaryTreeIterator
private static class	BinaryTree.Node

Nested classes/interfaces inherited from class java.util.AbstractMap

AbstractMap.SimpleEntry<K,V>, AbstractMap.SimpleImmutableEntry<K,V>

Nested classes/interfaces inherited from interface java.util.Map

Map.Entry<K,V>

Field Summary

Fields

Modifier and Type	Field and Description
private static String[]	_data_name
private Set[]	_entry_set
private static int	_INDEX_COUNT
private static int	_INDEX_SUM
private static int	_KEY
private Set[]	_key_set
private static int	_MINIMUM_INDEX
private int	_modifications
private BinaryTree.Node[]	_root
private int	_size
private static int	_VALUE
private Collection[]	_value_collection

Constructor Summary

Constructors

Constructor and Description
BinaryTree() Construct a new BinaryTree
BinaryTree(Map map) Constructs a new BinaryTree from an existing Map, with keys and values sorted

Method Summary

Methods

Modifier and Type	Method and Description
private static void	checkKey(Object key) check a key for validity (non-null and implements Comparable)
private static void	checkKeyAndValue(Object key, Object value) check a key and a value for validity (non-null and implements Comparable)
private static void	checkNonNullComparable(Object o, int index) check if an object is fit to be proper input ...
private static void	checkValue(Object value) check a value for validity (non-null and implements Comparable)
void	clear() Removes all mappings from this map
private static int	compare(Comparable o1, Comparable o2) Compare two objects
boolean	containsKey(Object key) Returns true if this map contains a mapping for the specified key.
boolean	containsValue(Object value) Returns true if this map maps one or more keys to the specified value.
private static void	copyColor(BinaryTree.Node from, BinaryTree.Node to, int index) copy the color from one node to another, dealing with the fact that one or both nodes may, in fact, be null
private Object	doGet(Comparable o, int index) common get logic, used to get by key or get by value
private void	doRedBlackDelete(BinaryTree.Node deleted_node) complicated red-black delete stuff.
private void	doRedBlackDeleteFixup(BinaryTree.Node replacement_node, int index) complicated red-black delete stuff.
private void	doRedBlackInsert(BinaryTree.Node inserted_node, int index) complicated red-black insert stuff.
private Object	doRemove(Comparable o, int index) common remove logic (remove by key or remove by value)
Set	entrySet() Returns a set view of the mappings contained in this map.
Set	entrySetByValue() Returns a set view of the mappings contained in this map.
Object	get(Object key) Returns the value to which this map maps the specified key.
private static BinaryTree.Node	getGrandParent(BinaryTree.Node node, int index) get a node's grandparent.
Object	getKeyForValue(Object value) Returns the key to which this map maps the specified value.
private static BinaryTree.Node	getLeftChild(BinaryTree.Node node, int index) get a node's left child.
private static BinaryTree.Node	getParent(BinaryTree.Node node, int index) get a node's parent.
private static BinaryTree.Node	getRightChild(BinaryTree.Node node, int index) get a node's right child.
private void	grow() bump up the size and note that the map has changed
private void	insertValue(BinaryTree.Node newNode) insert a node by its value
private static boolean	isBlack(BinaryTree.Node node, int index) is the specified black red? if the node does not exist, sure, it's black, thank you
private static boolean	isLeftChild(BinaryTree.Node node, int index) is this node its parent's left child? mind you, the node, or its parent, may not exist.
private static boolean	isRed(BinaryTree.Node node, int index) is the specified node red? if the node does not exist, no, it's black, thank you
private static boolean	isRightChild(BinaryTree.Node node, int index) is this node its parent's right child? mind you, the node, or its parent, may not exist.
Set	keySet() Returns a set view of the keys contained in this map.
Set	keySetByValue() Returns a set view of the keys contained in this map.
private static BinaryTree.Node	leastNode(BinaryTree.Node node, int index) find the least node from a given node.
private BinaryTree.Node	lookup(Comparable data, int index) do the actual lookup of a piece of data
private static void	makeBlack(BinaryTree.Node node, int index) force a node (if it exists) black
private static void	makeRed(BinaryTree.Node node, int index) force a node (if it exists) red
private void	modify() increment the modification count -- used to check for concurrent modification of the map through the map and through an Iterator from one of its Set or Collection views
private BinaryTree.Node	nextGreater(BinaryTree.Node node, int index) get the next larger node from the specified node
private int	oppositeIndex(int index) Get the opposite index of the specified index
Object	put(Object key, Object value) Associates the specified value with the specified key in this map.
Object	remove(Object key) Removes the mapping for this key from this map if present
Object	removeValue(Object value) Removes the mapping for this value from this map if present
private void	rotateLeft(BinaryTree.Node node, int index) do a rotate left.
private void	rotateRight(BinaryTree.Node node, int index) do a rotate right.
private void	shrink() decrement the size and note that the map has changed
int	size() Returns the number of key-value mappings in this map.
private void	swapPosition(BinaryTree.Node x, BinaryTree.Node y, int index) swap two nodes (except for their content), taking care of special cases where one is the other's parent ...
Collection	values() Returns a collection view of the values contained in this map.
Collection	valuesByValue() Returns a collection view of the values contained in this map.

Methods inherited from class java.util.AbstractMap

clone, equals, hashCode, isEmpty, putAll, toString

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

_root

private BinaryTree.Node[] _root

_size

private int _size

_modifications

private int _modifications

_key_set

private Set[] _key_set

_entry_set

private Set[] _entry_set

_value_collection

private Collection[] _value_collection

_KEY

private static final int _KEY

See Also:

Constant Field Values

_VALUE

private static final int _VALUE

See Also:

Constant Field Values

_INDEX_SUM

private static final int _INDEX_SUM

See Also:

Constant Field Values

_MINIMUM_INDEX

private static final int _MINIMUM_INDEX

See Also:

Constant Field Values

_INDEX_COUNT

private static final int _INDEX_COUNT

See Also:

Constant Field Values

_data_name

private static final String[] _data_name

Constructor Detail

BinaryTree

public BinaryTree()

Construct a new BinaryTree

BinaryTree

public BinaryTree(Map map)
           throws ClassCastException,
                  NullPointerException,
                  IllegalArgumentException

Constructs a new BinaryTree from an existing Map, with keys and values sorted

Parameters:

map - the map whose mappings are to be placed in this map.

Throws:

ClassCastException - if the keys in the map are not Comparable, or are not mutually comparable; also if the values in the map are not Comparable, or are not mutually Comparable

NullPointerException - if any key or value in the map is null

IllegalArgumentException - if there are duplicate keys or duplicate values in the map

Method Detail

getKeyForValue

public Object getKeyForValue(Object value)
                      throws ClassCastException,
                             NullPointerException

Returns the key to which this map maps the specified value. Returns null if the map contains no mapping for this value.

Parameters:

value - value whose associated key is to be returned.

Returns:

the key to which this map maps the specified value, or null if the map contains no mapping for this value.

Throws:

ClassCastException - if the value is of an inappropriate type for this map.

NullPointerException - if the value is null

removeValue

public Object removeValue(Object value)

Removes the mapping for this value from this map if present

Parameters:

value - value whose mapping is to be removed from the map.

Returns:

previous key associated with specified value, or null if there was no mapping for value.

entrySetByValue

public Set entrySetByValue()

Returns a set view of the mappings contained in this map. Each element in the returned set is a Map.Entry. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress, the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll and clear operations. It does not support the add or addAll operations.

The difference between this method and entrySet is that entrySet's iterator() method returns an iterator that iterates over the mappings in ascending order by key. This method's iterator method iterates over the mappings in ascending order by value.

Returns:

a set view of the mappings contained in this map.

keySetByValue

public Set keySetByValue()

Returns a set view of the keys contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress, the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll, and clear operations. It does not support the add or addAll operations.

The difference between this method and keySet is that keySet's iterator() method returns an iterator that iterates over the keys in ascending order by key. This method's iterator method iterates over the keys in ascending order by value.

Returns:

a set view of the keys contained in this map.

valuesByValue

public Collection valuesByValue()

Returns a collection view of the values contained in this map. The collection is backed by the map, so changes to the map are reflected in the collection, and vice-versa. If the map is modified while an iteration over the collection is in progress, the results of the iteration are undefined. The collection supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Collection.remove, removeAll, retainAll and clear operations. It does not support the add or addAll operations.

The difference between this method and values is that values's iterator() method returns an iterator that iterates over the values in ascending order by key. This method's iterator method iterates over the values in ascending order by key.

Returns:

a collection view of the values contained in this map.

doRemove

private Object doRemove(Comparable o,
              int index)

common remove logic (remove by key or remove by value)

Parameters:

o - the key, or value, that we're looking for

index - _KEY or _VALUE

Returns:

the key, if remove by value, or the value, if remove by key. null if the specified key or value could not be found

doGet

private Object doGet(Comparable o,
           int index)

common get logic, used to get by key or get by value

Parameters:

o - the key or value that we're looking for

index - _KEY or _VALUE

Returns:

the key (if the value was mapped) or the value (if the key was mapped); null if we couldn't find the specified object

oppositeIndex

private int oppositeIndex(int index)

Get the opposite index of the specified index

Parameters:

index - _KEY or _VALUE

Returns:

_VALUE (if _KEY was specified), else _KEY

lookup

private BinaryTree.Node lookup(Comparable data,
                     int index)

do the actual lookup of a piece of data

Parameters:

data - the key or value to be looked up

index - _KEY or _VALUE

Returns:

the desired Node, or null if there is no mapping of the specified data

compare

private static int compare(Comparable o1,
          Comparable o2)

Compare two objects

Parameters:

o1 - the first object

o2 - the second object

Returns:

negative value if o1 < o2; 0 if o1 == o2; positive value if o1 > o2

leastNode

private static BinaryTree.Node leastNode(BinaryTree.Node node,
                        int index)

find the least node from a given node. very useful for starting a sorting iterator ...

Parameters:

node - the node from which we will start searching

index - _KEY or _VALUE

Returns:

the smallest node, from the specified node, in the specified mapping

nextGreater

private BinaryTree.Node nextGreater(BinaryTree.Node node,
                          int index)

get the next larger node from the specified node

Parameters:

node - the node to be searched from

index - _KEY or _VALUE

Returns:

the specified node

copyColor

private static void copyColor(BinaryTree.Node from,
             BinaryTree.Node to,
             int index)

copy the color from one node to another, dealing with the fact that one or both nodes may, in fact, be null

Parameters:

from - the node whose color we're copying; may be null

to - the node whose color we're changing; may be null

index - _KEY or _VALUE

isRed

private static boolean isRed(BinaryTree.Node node,
            int index)

is the specified node red? if the node does not exist, no, it's black, thank you

Parameters:

node - the node (may be null) in question

index - _KEY or _VALUE

isBlack

private static boolean isBlack(BinaryTree.Node node,
              int index)

is the specified black red? if the node does not exist, sure, it's black, thank you

Parameters:

node - the node (may be null) in question

index - _KEY or _VALUE

makeRed

private static void makeRed(BinaryTree.Node node,
           int index)

force a node (if it exists) red

Parameters:

node - the node (may be null) in question

index - _KEY or _VALUE

makeBlack

private static void makeBlack(BinaryTree.Node node,
             int index)

force a node (if it exists) black

Parameters:

node - the node (may be null) in question

index - _KEY or _VALUE

getGrandParent

private static BinaryTree.Node getGrandParent(BinaryTree.Node node,
                             int index)

get a node's grandparent. mind you, the node, its parent, or its grandparent may not exist. no problem

Parameters:

node - the node (may be null) in question

index - _KEY or _VALUE

getParent

private static BinaryTree.Node getParent(BinaryTree.Node node,
                        int index)

get a node's parent. mind you, the node, or its parent, may not exist. no problem

Parameters:

node - the node (may be null) in question

index - _KEY or _VALUE

getRightChild

private static BinaryTree.Node getRightChild(BinaryTree.Node node,
                            int index)

get a node's right child. mind you, the node may not exist. no problem

Parameters:

node - the node (may be null) in question

index - _KEY or _VALUE

getLeftChild

private static BinaryTree.Node getLeftChild(BinaryTree.Node node,
                           int index)

get a node's left child. mind you, the node may not exist. no problem

Parameters:

node - the node (may be null) in question

index - _KEY or _VALUE

isLeftChild

private static boolean isLeftChild(BinaryTree.Node node,
                  int index)

is this node its parent's left child? mind you, the node, or its parent, may not exist. no problem. if the node doesn't exist ... it's its non-existent parent's left child. If the node does exist but has no parent ... no, we're not the non-existent parent's left child. Otherwise (both the specified node AND its parent exist), check.

Parameters:

node - the node (may be null) in question

index - _KEY or _VALUE

isRightChild

private static boolean isRightChild(BinaryTree.Node node,
                   int index)

is this node its parent's right child? mind you, the node, or its parent, may not exist. no problem. if the node doesn't exist ... it's its non-existent parent's right child. If the node does exist but has no parent ... no, we're not the non-existent parent's right child. Otherwise (both the specified node AND its parent exist), check.

Parameters:

node - the node (may be null) in question

index - _KEY or _VALUE

rotateLeft

private void rotateLeft(BinaryTree.Node node,
              int index)

do a rotate left. standard fare in the world of balanced trees

Parameters:

node - the node to be rotated

index - _KEY or _VALUE

rotateRight

private void rotateRight(BinaryTree.Node node,
               int index)

do a rotate right. standard fare in the world of balanced trees

Parameters:

node - the node to be rotated

index - _KEY or _VALUE

doRedBlackInsert

private void doRedBlackInsert(BinaryTree.Node inserted_node,
                    int index)

complicated red-black insert stuff. Based on Sun's TreeMap implementation, though it's barely recognizeable any more

Parameters:

inserted_node - the node to be inserted

index - _KEY or _VALUE

doRedBlackDelete

private void doRedBlackDelete(BinaryTree.Node deleted_node)

complicated red-black delete stuff. Based on Sun's TreeMap implementation, though it's barely recognizeable any more

Parameters:

deleted_node - the node to be deleted

doRedBlackDeleteFixup

private void doRedBlackDeleteFixup(BinaryTree.Node replacement_node,
                         int index)

complicated red-black delete stuff. Based on Sun's TreeMap implementation, though it's barely recognizeable any more. This rebalances the tree (somewhat, as red-black trees are not perfectly balanced -- perfect balancing takes longer)

Parameters:

replacement_node - the node being replaced

index - _KEY or _VALUE

swapPosition

private void swapPosition(BinaryTree.Node x,
                BinaryTree.Node y,
                int index)

swap two nodes (except for their content), taking care of special cases where one is the other's parent ... hey, it happens.

Parameters:

x - one node

y - another node

index - _KEY or _VALUE

checkNonNullComparable

private static void checkNonNullComparable(Object o,
                          int index)

check if an object is fit to be proper input ... has to be Comparable and non-null

Parameters:

o - the object being checked

index - _KEY or _VALUE (used to put the right word in the exception message)

Throws:

NullPointerException - if o is null

ClassCastException - if o is not Comparable

checkKey

private static void checkKey(Object key)

check a key for validity (non-null and implements Comparable)

Parameters:

key - the key to be checked

Throws:

NullPointerException - if key is null

ClassCastException - if key is not Comparable

checkValue

private static void checkValue(Object value)

check a value for validity (non-null and implements Comparable)

Parameters:

value - the value to be checked

Throws:

NullPointerException - if value is null

ClassCastException - if value is not Comparable

checkKeyAndValue

private static void checkKeyAndValue(Object key,
                    Object value)

check a key and a value for validity (non-null and implements Comparable)

Parameters:

key - the key to be checked

value - the value to be checked

Throws:

NullPointerException - if key or value is null

ClassCastException - if key or value is not Comparable

modify

private void modify()

increment the modification count -- used to check for concurrent modification of the map through the map and through an Iterator from one of its Set or Collection views

grow

private void grow()

bump up the size and note that the map has changed

shrink

private void shrink()

decrement the size and note that the map has changed

insertValue

private void insertValue(BinaryTree.Node newNode)
                  throws IllegalArgumentException

insert a node by its value

Parameters:

newNode - the node to be inserted

Throws:

IllegalArgumentException - if the node already exists in the value mapping

size

public int size()

Returns the number of key-value mappings in this map. If the map contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.

Specified by:

size in interface Map

Overrides:

size in class AbstractMap

Returns:

the number of key-value mappings in this map.

containsKey

public boolean containsKey(Object key)
                    throws ClassCastException,
                           NullPointerException

Returns true if this map contains a mapping for the specified key.

Specified by:

containsKey in interface Map

Overrides:

containsKey in class AbstractMap

Parameters:

key - key whose presence in this map is to be tested.

Returns:

true if this map contains a mapping for the specified key.

Throws:

ClassCastException - if the key is of an inappropriate type for this map.

NullPointerException - if the key is null

containsValue

public boolean containsValue(Object value)

Returns true if this map maps one or more keys to the specified value.

Specified by:

containsValue in interface Map

Overrides:

containsValue in class AbstractMap

Parameters:

value - value whose presence in this map is to be tested.

Returns:

true if this map maps one or more keys to the specified value.

get

public Object get(Object key)
           throws ClassCastException,
                  NullPointerException

Returns the value to which this map maps the specified key. Returns null if the map contains no mapping for this key.

Specified by:

get in interface Map

Overrides:

get in class AbstractMap

Parameters:

key - key whose associated value is to be returned.

Returns:

the value to which this map maps the specified key, or null if the map contains no mapping for this key.

Throws:

ClassCastException - if the key is of an inappropriate type for this map.

NullPointerException - if the key is null

put

public Object put(Object key,
         Object value)
           throws ClassCastException,
                  NullPointerException,
                  IllegalArgumentException

Associates the specified value with the specified key in this map.

Specified by:

put in interface Map

Overrides:

put in class AbstractMap

Parameters:

key - key with which the specified value is to be associated.

value - value to be associated with the specified key.

Returns:

null

Throws:

ClassCastException - if the class of the specified key or value prevents it from being stored in this map.

NullPointerException - if the specified key or value is null

IllegalArgumentException - if the key duplicates an existing key, or if the value duplicates an existing value

remove

public Object remove(Object key)

Removes the mapping for this key from this map if present

Specified by:

remove in interface Map

Overrides:

remove in class AbstractMap

Parameters:

key - key whose mapping is to be removed from the map.

Returns:

previous value associated with specified key, or null if there was no mapping for key.

clear

public void clear()

Removes all mappings from this map

Specified by:

clear in interface Map

Overrides:

clear in class AbstractMap

keySet

public Set keySet()

Returns a set view of the keys contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress, the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll, and clear operations. It does not support the add or addAll operations.

Specified by:

keySet in interface Map

Overrides:

keySet in class AbstractMap

Returns:

a set view of the keys contained in this map.

values

public Collection values()

Returns a collection view of the values contained in this map. The collection is backed by the map, so changes to the map are reflected in the collection, and vice-versa. If the map is modified while an iteration over the collection is in progress, the results of the iteration are undefined. The collection supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Collection.remove, removeAll, retainAll and clear operations. It does not support the add or addAll operations.

Specified by:

values in interface Map

Overrides:

values in class AbstractMap

Returns:

a collection view of the values contained in this map.

entrySet

public Set entrySet()

Returns a set view of the mappings contained in this map. Each element in the returned set is a Map.Entry. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress, the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll and clear operations. It does not support the add or addAll operations.

Specified by:

entrySet in interface Map

Specified by:

entrySet in class AbstractMap

Returns:

a set view of the mappings contained in this map.