uk.co.omegaprime.btreemap

Class BTreeMap<K,V>

java.lang.Object

uk.co.omegaprime.btreemap.BTreeMap<K,V>

Type Parameters:

K - Type of keys

V - Type of values

All Implemented Interfaces:

java.util.Map<K,V>, java.util.NavigableMap<K,V>, java.util.SortedMap<K,V>

public class BTreeMap<K,V>
extends java.lang.Object
implements java.util.NavigableMap<K,V>

A B-tree based NavigableMap implementation.

To get started, call create().

All values in the map are stored at leaf nodes, and all leaf nodes are at the same depth. This ensures that accesses to the map via e.g. get, put and remove all take log(n) time. In contrast to a balanced binary tree (like that used by TreeMap), each node may holds more than one key. This makes the datastructure more cache-friendly: you can expect it to be around 50% faster than TreeMap for workloads that do not fit in cache.

The map is sorted either according to the Comparable method of the key type, or via a user-supplied Comparator. This ordering should be consistent with equals.

The implementation is unsynchronized, and there are no guarantees as to what will happen if you make use of iterator that was created before some operation that modified the map.

Entry instances returned by this class are immutable and hence do not support the Entry#setValue(Object) method.

Nested Class Summary

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

java.util.Map.Entry<K,V>

Method Summary

Modifier and Type	Method and Description
java.util.Map.Entry<K,V>	ceilingEntry(K key)
K	ceilingKey(K key)
void	clear()
java.util.Comparator<? super K>	comparator()
boolean	containsKey(java.lang.Object key)
boolean	containsValue(java.lang.Object value)
static <K extends java.lang.Comparable<? super K>,V> BTreeMap<K,V>	create()
static <K,V> BTreeMap<K,V>	create(java.util.Comparator<K> comparator)
static <K,V> BTreeMap<K,V>	create(java.util.Map<? extends K,? extends V> that)
static <K,V> BTreeMap<K,V>	create(java.util.SortedMap<K,? extends V> that)
java.util.NavigableSet<K>	descendingKeySet()
java.util.NavigableMap<K,V>	descendingMap()
java.util.Set<java.util.Map.Entry<K,V>>	entrySet()
boolean	equals(java.lang.Object that)
java.util.Map.Entry<K,V>	firstEntry()
K	firstKey()
java.util.Map.Entry<K,V>	floorEntry(K key)
K	floorKey(K key)
V	get(java.lang.Object key)
V	getOrDefault(java.lang.Object key, V dflt)
int	hashCode()
java.util.SortedMap<K,V>	headMap(K toKey)
java.util.NavigableMap<K,V>	headMap(K toKey, boolean inclusive)
java.util.Map.Entry<K,V>	higherEntry(K key)
K	higherKey(K key)
boolean	isEmpty()
java.util.NavigableSet<K>	keySet()
java.util.Map.Entry<K,V>	lastEntry()
K	lastKey()
java.util.Map.Entry<K,V>	lowerEntry(K key)
K	lowerKey(K key)
java.util.NavigableSet<K>	navigableKeySet()
java.util.Map.Entry<K,V>	pollFirstEntry()
java.util.Map.Entry<K,V>	pollLastEntry()
V	put(K key, V value)
void	putAll(java.util.Map<? extends K,? extends V> that)
V	remove(java.lang.Object key)
int	size()
java.util.NavigableMap<K,V>	subMap(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive)
java.util.SortedMap<K,V>	subMap(K fromKey, K toKey)
java.util.SortedMap<K,V>	tailMap(K fromKey)
java.util.NavigableMap<K,V>	tailMap(K fromKey, boolean inclusive)
java.lang.String	toString()
java.util.Collection<V>	values()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, forEach, merge, putIfAbsent, remove, replace, replace, replaceAll

Method Detail

create

public static <K extends java.lang.Comparable<? super K>,V> BTreeMap<K,V> create()

create

public static <K,V> BTreeMap<K,V> create(java.util.Comparator<K> comparator)

Parameters:

comparator - If null, the natural order of the keys will be used

create

public static <K,V> BTreeMap<K,V> create(java.util.SortedMap<K,? extends V> that)

create

public static <K,V> BTreeMap<K,V> create(java.util.Map<? extends K,? extends V> that)

clear

public void clear()

Specified by:

clear in interface java.util.Map<K,V>

comparator

public java.util.Comparator<? super K> comparator()

Specified by:

comparator in interface java.util.SortedMap<K,V>

putAll

public void putAll(java.util.Map<? extends K,? extends V> that)

Specified by:

putAll in interface java.util.Map<K,V>

get

public V get(java.lang.Object key)

Specified by:

get in interface java.util.Map<K,V>

getOrDefault

public V getOrDefault(java.lang.Object key,
                      V dflt)

Specified by:

getOrDefault in interface java.util.Map<K,V>

containsKey

public boolean containsKey(java.lang.Object key)

Specified by:

containsKey in interface java.util.Map<K,V>

put

public V put(K key,
             V value)

Specified by:

put in interface java.util.Map<K,V>

size

public int size()

Specified by:

size in interface java.util.Map<K,V>

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface java.util.Map<K,V>

containsValue

public boolean containsValue(java.lang.Object value)

Specified by:

containsValue in interface java.util.Map<K,V>

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

equals

public boolean equals(java.lang.Object that)

Specified by:

equals in interface java.util.Map<K,V>

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Specified by:

hashCode in interface java.util.Map<K,V>

Overrides:

hashCode in class java.lang.Object

lowerEntry

public java.util.Map.Entry<K,V> lowerEntry(K key)

Specified by:

lowerEntry in interface java.util.NavigableMap<K,V>

lowerKey

public K lowerKey(K key)

Specified by:

lowerKey in interface java.util.NavigableMap<K,V>

floorEntry

public java.util.Map.Entry<K,V> floorEntry(K key)

Specified by:

floorEntry in interface java.util.NavigableMap<K,V>

floorKey

public K floorKey(K key)

Specified by:

floorKey in interface java.util.NavigableMap<K,V>

ceilingEntry

public java.util.Map.Entry<K,V> ceilingEntry(K key)

Specified by:

ceilingEntry in interface java.util.NavigableMap<K,V>

ceilingKey

public K ceilingKey(K key)

Specified by:

ceilingKey in interface java.util.NavigableMap<K,V>

higherEntry

public java.util.Map.Entry<K,V> higherEntry(K key)

Specified by:

higherEntry in interface java.util.NavigableMap<K,V>

higherKey

public K higherKey(K key)

Specified by:

higherKey in interface java.util.NavigableMap<K,V>

firstEntry

public java.util.Map.Entry<K,V> firstEntry()

Specified by:

firstEntry in interface java.util.NavigableMap<K,V>

lastEntry

public java.util.Map.Entry<K,V> lastEntry()

Specified by:

lastEntry in interface java.util.NavigableMap<K,V>

pollFirstEntry

public java.util.Map.Entry<K,V> pollFirstEntry()

Specified by:

pollFirstEntry in interface java.util.NavigableMap<K,V>

pollLastEntry

public java.util.Map.Entry<K,V> pollLastEntry()

Specified by:

pollLastEntry in interface java.util.NavigableMap<K,V>

descendingMap

public java.util.NavigableMap<K,V> descendingMap()

Specified by:

descendingMap in interface java.util.NavigableMap<K,V>

navigableKeySet

public java.util.NavigableSet<K> navigableKeySet()

Specified by:

navigableKeySet in interface java.util.NavigableMap<K,V>

descendingKeySet

public java.util.NavigableSet<K> descendingKeySet()

Specified by:

descendingKeySet in interface java.util.NavigableMap<K,V>

subMap

public java.util.NavigableMap<K,V> subMap(K fromKey,
                                          boolean fromInclusive,
                                          K toKey,
                                          boolean toInclusive)

Specified by:

subMap in interface java.util.NavigableMap<K,V>

headMap

public java.util.NavigableMap<K,V> headMap(K toKey,
                                           boolean inclusive)

Specified by:

headMap in interface java.util.NavigableMap<K,V>

tailMap

public java.util.NavigableMap<K,V> tailMap(K fromKey,
                                           boolean inclusive)

Specified by:

tailMap in interface java.util.NavigableMap<K,V>

subMap

public java.util.SortedMap<K,V> subMap(K fromKey,
                                       K toKey)

Specified by:

subMap in interface java.util.NavigableMap<K,V>

Specified by:

subMap in interface java.util.SortedMap<K,V>

headMap

public java.util.SortedMap<K,V> headMap(K toKey)

Specified by:

headMap in interface java.util.NavigableMap<K,V>

Specified by:

headMap in interface java.util.SortedMap<K,V>

tailMap

public java.util.SortedMap<K,V> tailMap(K fromKey)

Specified by:

tailMap in interface java.util.NavigableMap<K,V>

Specified by:

tailMap in interface java.util.SortedMap<K,V>

firstKey

public K firstKey()

Specified by:

firstKey in interface java.util.SortedMap<K,V>

lastKey

public K lastKey()

Specified by:

lastKey in interface java.util.SortedMap<K,V>

keySet

public java.util.NavigableSet<K> keySet()

Specified by:

keySet in interface java.util.Map<K,V>

Specified by:

keySet in interface java.util.SortedMap<K,V>

values

public java.util.Collection<V> values()

Specified by:

values in interface java.util.Map<K,V>

Specified by:

values in interface java.util.SortedMap<K,V>

entrySet

public java.util.Set<java.util.Map.Entry<K,V>> entrySet()

Specified by:

entrySet in interface java.util.Map<K,V>

Specified by:

entrySet in interface java.util.SortedMap<K,V>

remove

public V remove(java.lang.Object key)

Specified by:

remove in interface java.util.Map<K,V>