org.mapdb

Class HTreeMap<K,V>

java.lang.Object

java.util.AbstractMap<K,V>

org.mapdb.HTreeMap<K,V>

All Implemented Interfaces:

java.io.Closeable, java.io.Serializable, java.lang.AutoCloseable, java.util.concurrent.ConcurrentMap<K,V>, java.util.Map<K,V>, Bind.MapWithModificationListener<K,V>

public class HTreeMap<K,V>
extends java.util.AbstractMap<K,V>
implements java.util.concurrent.ConcurrentMap<K,V>, Bind.MapWithModificationListener<K,V>, java.io.Closeable, java.io.Serializable

Thread safe concurrent HashMap

This map uses full 32bit hash from beginning, There is no initial load factor and rehash. Technically it is not hash table, but hash tree with nodes expanding when they become full.

This map is suitable for number of records 1e9 and over. Larger number of records will increase hash collisions and performance will degrade linearly with number of records (separate chaining).

Concurrent scalability is achieved by splitting HashMap into 16 segments, each with separate lock. Very similar to ConcurrentHashMap

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	HTreeMap.KeySet

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

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

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

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

Constructor Summary

Constructors

Constructor and Description

HTreeMap(Engine[] engines, boolean closeEngine, long[] counterRecids, int hashSalt, long[] segmentRecids, Serializer<K> keySerializer, Serializer<V> valueSerializer, long expireTimeStart, long expire, long expireAccess, long expireMaxSize, long expireStoreSize, long[] expireHeads, long[] expireTails, Fun.Function1<V,K> valueCreator, java.util.concurrent.ScheduledExecutorService executor, long executorPeriod, boolean closeExecutor, java.util.concurrent.locks.Lock consistencyLock) Opens HTreeMap

Method Summary

Modifier and Type	Method and Description
void	clear()
void	close()
boolean	containsKey(java.lang.Object o)
boolean	containsValue(java.lang.Object value)
java.util.Set<java.util.Map.Entry<K,V>>	entrySet()
V	get(java.lang.Object o)
Engine	getEngine()
long	getMaxExpireTime() Returns maximal (newest) expiration timestamp
long	getMinExpireTime() Returns minimal (oldest) expiration timestamp
V	getPeek(java.lang.Object key) Return given value, without updating cache statistics if expireAccess() is true It also does not use valueCreator if value is not found (always returns null if not found)
boolean	isEmpty()
java.util.Set<K>	keySet()
long	mappingCount()
void	modificationListenerAdd(Bind.MapListener<K,V> listener) Add new modification listener notified when Map has been updated
void	modificationListenerRemove(Bind.MapListener<K,V> listener) Remove registered notification listener
V	put(K key, V value)
V	putIfAbsent(K key, V value)
V	remove(java.lang.Object key)
boolean	remove(java.lang.Object key, java.lang.Object value)
V	replace(K key, V value)
boolean	replace(K key, V oldValue, V newValue)
int	size()
long	sizeLong()
java.util.Map<K,V>	snapshot() Make readonly snapshot view of current Map.
java.util.Collection<V>	values()

Methods inherited from class java.util.AbstractMap

equals, hashCode, putAll, toString

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.concurrent.ConcurrentMap

compute, computeIfAbsent, computeIfPresent, forEach, getOrDefault, merge, replaceAll

Methods inherited from interface java.util.Map

equals, hashCode, putAll

Constructor Detail

HTreeMap

public HTreeMap(Engine[] engines,
                boolean closeEngine,
                long[] counterRecids,
                int hashSalt,
                long[] segmentRecids,
                Serializer<K> keySerializer,
                Serializer<V> valueSerializer,
                long expireTimeStart,
                long expire,
                long expireAccess,
                long expireMaxSize,
                long expireStoreSize,
                long[] expireHeads,
                long[] expireTails,
                Fun.Function1<V,K> valueCreator,
                java.util.concurrent.ScheduledExecutorService executor,
                long executorPeriod,
                boolean closeExecutor,
                java.util.concurrent.locks.Lock consistencyLock)

Opens HTreeMap

Method Detail

containsKey

public boolean containsKey(java.lang.Object o)

Specified by:

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

Overrides:

containsKey in class java.util.AbstractMap<K,V>

size

public int size()

Specified by:

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

Overrides:

size in class java.util.AbstractMap<K,V>

sizeLong

public long sizeLong()

Specified by:

sizeLong in interface Bind.MapWithModificationListener<K,V>

Returns:

size of map, but in 64bit long which does not overflow at 2e9 items.

mappingCount

public long mappingCount()

isEmpty

public boolean isEmpty()

Specified by:

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

Overrides:

isEmpty in class java.util.AbstractMap<K,V>

get

public V get(java.lang.Object o)

Specified by:

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

Overrides:

get in class java.util.AbstractMap<K,V>

getPeek

public V getPeek(java.lang.Object key)

Return given value, without updating cache statistics if expireAccess() is true It also does not use valueCreator if value is not found (always returns null if not found)

Parameters:

key - key to lookup

Returns:

value associated with key or null

put

public V put(K key,
             V value)

Specified by:

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

Overrides:

put in class java.util.AbstractMap<K,V>

remove

public V remove(java.lang.Object key)

Specified by:

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

Overrides:

remove in class java.util.AbstractMap<K,V>

clear

public void clear()

Specified by:

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

Overrides:

clear in class java.util.AbstractMap<K,V>

containsValue

public boolean containsValue(java.lang.Object value)

Specified by:

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

Overrides:

containsValue in class java.util.AbstractMap<K,V>

keySet

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

Specified by:

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

Overrides:

keySet in class java.util.AbstractMap<K,V>

values

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

Specified by:

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

Overrides:

values in class java.util.AbstractMap<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 class java.util.AbstractMap<K,V>

putIfAbsent

public V putIfAbsent(K key,
                     V value)

Specified by:

putIfAbsent in interface java.util.concurrent.ConcurrentMap<K,V>

Specified by:

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

remove

public boolean remove(java.lang.Object key,
                      java.lang.Object value)

Specified by:

remove in interface java.util.concurrent.ConcurrentMap<K,V>

Specified by:

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

replace

public boolean replace(K key,
                       V oldValue,
                       V newValue)

Specified by:

replace in interface java.util.concurrent.ConcurrentMap<K,V>

Specified by:

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

replace

public V replace(K key,
                 V value)

Specified by:

replace in interface java.util.concurrent.ConcurrentMap<K,V>

Specified by:

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

getMaxExpireTime

public long getMaxExpireTime()

Returns maximal (newest) expiration timestamp

getMinExpireTime

public long getMinExpireTime()

Returns minimal (oldest) expiration timestamp

snapshot

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

Make readonly snapshot view of current Map. Snapshot is immutable and not affected by modifications made by other threads. Useful if you need consistent view on Map.

Maintaining snapshot have some overhead, underlying Engine is closed after Map view is GCed. Please make sure to release reference to this Map view, so snapshot view can be garbage collected.

Returns:

snapshot

modificationListenerAdd

public void modificationListenerAdd(Bind.MapListener<K,V> listener)

Description copied from interface: Bind.MapWithModificationListener

Add new modification listener notified when Map has been updated

Specified by:

modificationListenerAdd in interface Bind.MapWithModificationListener<K,V>

Parameters:

listener - callback interface notified when map changes

modificationListenerRemove

public void modificationListenerRemove(Bind.MapListener<K,V> listener)

Description copied from interface: Bind.MapWithModificationListener

Remove registered notification listener

Specified by:

modificationListenerRemove in interface Bind.MapWithModificationListener<K,V>

Parameters:

listener - callback interface notified when map changes

getEngine

public Engine getEngine()

close

public void close()

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable