Package com.github.dagnelies.filemap

Class IndexedFileMap<K,V>

java.lang.Object

com.github.dagnelies.filemap.AbstractFileMap<K,V>

com.github.dagnelies.filemap.IndexedFileMap<K,V>

Type Parameters:

K -

V -

All Implemented Interfaces:

FileMap<K,V>, Map<K,V>

public class IndexedFileMap<K,V>
extends AbstractFileMap<K,V>

This thread safe hash map stores its key/values on disk. Only the keys are are in memory, along with the value's position in the file. This allows to store much more data than would normally fit in memory. Each insertion/update/removal is saved to the file in a readable JSON format. Note that the file works like a log and old entries are not "removed". They will only be overridden. This means that the file only grows.

Author:

dagnelies

Nested Class Summary

Nested classes/interfaces inherited from class com.github.dagnelies.filemap.AbstractFileMap

AbstractFileMap.LineEntry

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

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

Field Summary

Fields inherited from class com.github.dagnelies.filemap.AbstractFileMap

file, fileio

Constructor Summary

Constructors

Constructor	Description
IndexedFileMap(File file, Class<K> keyType, Class<V> valueType)

Method Summary

Modifier and Type	Method	Description
void	clear()
boolean	containsKey(Object key)
boolean	containsValue(Object value)
Iterable<AbstractFileMap.LineEntry>	entries()
Set<Map.Entry<K,V>>	entrySet()
V	get(Object key)
protected void	init()
boolean	isEmpty()
Set<K>	keySet()
protected void	loadEntry(long offset, String line)
V	put(K key, V value)
V	remove(Object key)
int	size()
Collection<V>	values()

Methods inherited from class com.github.dagnelies.filemap.AbstractFileMap

clearLines, close, diskSize, getEntriesWritten, getFile, getFragmentation, parseKey, parseLine, parseValue, putAll, readLine, writeLine

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

Constructor Detail

IndexedFileMap

public IndexedFileMap(File file,
                      Class<K> keyType,
                      Class<V> valueType)
               throws IOException

Throws:

IOException

Method Detail

init

protected void init()
             throws IOException

Specified by:

init in class AbstractFileMap<K,V>

Throws:

IOException

loadEntry

protected void loadEntry(long offset,
                         String line)
                  throws IOException

Specified by:

loadEntry in class AbstractFileMap<K,V>

Throws:

IOException

size

public int size()

isEmpty

public boolean isEmpty()

containsKey

public boolean containsKey(Object key)

containsValue

public boolean containsValue(Object value)

get

public V get(Object key)

put

public V put(K key,
             V value)

remove

public V remove(Object key)

clear

public void clear()

keySet

public Set<K> keySet()

values

public Collection<V> values()

entrySet

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

entries

public Iterable<AbstractFileMap.LineEntry> entries()