jadex.commons.collection

Class ShadowedPersistentMap<K,V>

java.lang.Object

jadex.commons.collection.ShadowedPersistentMap<K,V>

All Implemented Interfaces:

java.util.Map<K,V>

public class ShadowedPersistentMap<K,V>
extends java.lang.Object
implements java.util.Map<K,V>

A map implementation supporting automatic serialization its data and persisting it on disk using a shadow map during compaction.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	ShadowedPersistentMap.DeletedKey Marker for deleted entries.
protected class	ShadowedPersistentMap.ValueInfo Information about a stored value.

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

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

Field Summary

Fields

Modifier and Type	Field and Description
protected long	autocompactionthreshold Dirty threshold for auto-compaction.
protected java.lang.ClassLoader	classloader Class loader used for serialization.
protected ShadowedPersistentMap<java.lang.Object,java.lang.Object>	compactionshadowmap Shadow map used during compaction.
protected long	dirtybytes Bytes of dirty entries.
protected java.io.File	file The persistence file.
protected java.util.Map<K,ShadowedPersistentMap.ValueInfo>	indexmap The index map, key to position and size of value.
protected java.lang.String	mode The file access mode.
protected java.io.RandomAccessFile	raf Random access to the persistence file
protected int	shadowcounter Object counter for shadow map.
protected java.lang.Object	shadowlock Lock for the compaction shadow map.

Constructor Summary

Constructors

Constructor and Description
ShadowedPersistentMap(java.io.File file, boolean synchronous, java.lang.ClassLoader classloader) Creates the map.

Method Summary

Modifier and Type	Method and Description
protected void	buildIndex() Builds the index.
void	clear() Removes all of the entries from this map.
void	close() Closes the persistence file.
void	compact() Removes stale entries and compacts the map.
boolean	containsKey(java.lang.Object key) Returns whether this map contains the specified key.
boolean	containsValue(java.lang.Object value) Returns whether the map contains the specified value.
protected V	doPut(K key, V value) Commits a value to the map
V	doRemove(java.lang.Object key)
java.util.Set<java.util.Map.Entry<K,V>>	entrySet() Returns the map's entry set.
V	get(java.lang.Object key) Returns the value for a specified key.
long	getDirtyBytes() Returns the bytes wasted due to stale entries.
boolean	isEmpty() Returns whether this map is empty.
java.util.Set<K>	keySet() Returns the keys of the map.
static void	main(java.lang.String[] args) Test main method.
V	put(K key, V value) Puts a new value in the map.
void	putAll(java.util.Map<? extends K,? extends V> m) Copies entries from the specified map to this map,
V	remove(java.lang.Object key) Removes a map entry.
void	setAutoCompactionThreshold(long threshold) Sets the threshold of stale bytes before auto-compaction is executed.
int	size() Returns the size of the map.
java.util.Collection<V>	values() Returns the values of the map.
void	waitForCompaction() Waits for a background compaction to finish (if running).

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

Field Detail

indexmap

protected java.util.Map<K,ShadowedPersistentMap.ValueInfo> indexmap

The index map, key to position and size of value.

file

protected java.io.File file

The persistence file.

mode

protected java.lang.String mode

The file access mode.

raf

protected java.io.RandomAccessFile raf

Random access to the persistence file

dirtybytes

protected long dirtybytes

Bytes of dirty entries.

autocompactionthreshold

protected long autocompactionthreshold

Dirty threshold for auto-compaction.

classloader

protected java.lang.ClassLoader classloader

Class loader used for serialization.

shadowlock

protected java.lang.Object shadowlock

Lock for the compaction shadow map.

shadowcounter

protected int shadowcounter

Object counter for shadow map.

compactionshadowmap

protected volatile ShadowedPersistentMap<java.lang.Object,java.lang.Object> compactionshadowmap

Shadow map used during compaction.

Constructor Detail

ShadowedPersistentMap

public ShadowedPersistentMap(java.io.File file,
                             boolean synchronous,
                             java.lang.ClassLoader classloader)

Creates the map.

Parameters:

file - File used for persistent data.

Method Detail

main

public static void main(java.lang.String[] args)

Test main method.

Parameters:

args - Arguments.

size

public int size()

Returns the size of the map.

Specified by:

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

isEmpty

public boolean isEmpty()

Returns whether this map is empty.

Specified by:

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

containsKey

public boolean containsKey(java.lang.Object key)

Returns whether this map contains the specified key.

Specified by:

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

containsValue

public boolean containsValue(java.lang.Object value)

Returns whether the map contains the specified value. NOTE: This is very slow, use with caution.

Specified by:

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

get

public V get(java.lang.Object key)

Returns the value for a specified key.

Specified by:

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

put

public V put(K key,
             V value)

Puts a new value in the map.

Specified by:

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

remove

public V remove(java.lang.Object key)

Removes a map entry.

Specified by:

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

putAll

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

Copies entries from the specified map to this map,

Specified by:

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

clear

public void clear()

Removes all of the entries from this map.

Specified by:

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

keySet

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

Returns the keys of the map. Note: Unlike other maps, this is the preferred (fastest mode) for iteration.

Specified by:

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

values

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

Returns the values of the map. NOTE: This is very slow, use with caution.

Specified by:

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

entrySet

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

Returns the map's entry set. Warning: SLOW!

Specified by:

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

compact

public void compact()

Removes stale entries and compacts the map.

waitForCompaction

public void waitForCompaction()

Waits for a background compaction to finish (if running).

close

public void close()

Closes the persistence file. The map ceases to function after calling this.

getDirtyBytes

public long getDirtyBytes()

Returns the bytes wasted due to stale entries.

setAutoCompactionThreshold

public void setAutoCompactionThreshold(long threshold)

Sets the threshold of stale bytes before auto-compaction is executed. Setting the threshold to Long.MAX_VALUE disables auto-compaction.

buildIndex

protected void buildIndex()

Builds the index.

doPut

protected V doPut(K key,
                  V value)

Commits a value to the map

doRemove

public V doRemove(java.lang.Object key)