Package com.gengoai.collection.disk

Class DiskMap<K,V>

java.lang.Object

com.gengoai.collection.disk.DiskMap<K,V>

Type Parameters:

K - the key type parameter

V - the value type parameter

All Implemented Interfaces:

Serializable, AutoCloseable, Map<K,V>

public class DiskMap<K,V>
extends Object
implements Map<K,V>, AutoCloseable, Serializable

A Map implementation that stores its data in a file. Each map file can contain multiple maps where each map is stored in a namespace represented by a unique String name. DiskMaps are monitored to ensure that their file handle is properly closed if the it is no longer in use. However, one can use the commit and close methods to explicitly commit changes and close the map.

DiskMaps are created using a builder in the following way:

 
  var map = DiskMap.builder()
                   .file(Resources.from("/data/map.db")
                   .namespace("people")
                   .compressed(true)
                   .build();
 
 

Once an DiskMap instance is constructed it acts like regular Java Map.

See Also:

Serialized Form

Nested Class Summary

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

Map.Entry<K extends Object,V extends Object>

Method Summary

Modifier and Type	Method	Description
void	clear()
void	close()
void	commit()	Commits any changes made to disk.
boolean	containsKey(Object o)
boolean	containsValue(Object o)
Set<Map.Entry<K,V>>	entrySet()
V	get(Object o)
MapDBHandle	getHandle()	Gets the MapDBHandle that manages the map database
boolean	isEmpty()
Set<K>	keySet()
V	put(K k, V v)
void	putAll(Map<? extends K,? extends V> map)
V	remove(Object o)
int	size()
Collection<V>	values()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Map

compute, computeIfAbsent, computeIfPresent, equals, forEach, getOrDefault, hashCode, merge, putIfAbsent, remove, replace, replace, replaceAll

Method Detail

clear

public void clear()

Specified by:

clear in interface Map<K,V>

close

public void close()
           throws Exception

Specified by:

close in interface AutoCloseable

Throws:

Exception

commit

public void commit()

Commits any changes made to disk.

containsKey

public boolean containsKey(Object o)

Specified by:

containsKey in interface Map<K,V>

containsValue

public boolean containsValue(Object o)

Specified by:

containsValue in interface Map<K,V>

entrySet

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

Specified by:

entrySet in interface Map<K,V>

get

public V get(Object o)

Specified by:

get in interface Map<K,V>

getHandle

public MapDBHandle getHandle()

Gets the MapDBHandle that manages the map database

Returns:

the handle

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface Map<K,V>

keySet

public Set<K> keySet()

Specified by:

keySet in interface Map<K,V>

put

public V put(K k,
             V v)

Specified by:

put in interface Map<K,V>

putAll

public void putAll(Map<? extends K,? extends V> map)

Specified by:

putAll in interface Map<K,V>

remove

public V remove(Object o)

Specified by:

remove in interface Map<K,V>

size

public int size()

Specified by:

size in interface Map<K,V>

values

public Collection<V> values()

Specified by:

values in interface Map<K,V>