org.pfsw.util

Class TemporaryMap<K,V>

java.lang.Object

org.pfsw.util.TemporaryMap<K,V>

All Implemented Interfaces:

java.io.Serializable, java.util.Map<K,V>, TriggerClient

public class TemporaryMap<K,V>
extends java.lang.Object
implements java.util.Map<K,V>, TriggerClient, java.io.Serializable

This implementation of a Map behaves like a HashMap except that it associates a timestamp with each entry. Periodically it checks all its entries' timestamp against an expire period. If an entry is expired it will be automatically removed. Therefore all elements just live temporarily in this map.

See Also:

Serialized Form

Nested Class Summary

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

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

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	TemporaryMap()
	TemporaryMap(long expiresAfterMs, long checkAfterMs) Initialize the new instance with values that define the expiration of any object in the map and the interval for checking if expired objects are in the map.

Method Summary

Modifier and Type	Method and Description
boolean	canBeTriggeredBy(Trigger trigger) FOR INTERNAL USE ONLY! Will be called by a Trigger to check if object clean-up can be executed.
void	clear()
boolean	containsKey(java.lang.Object key) This method returns true, if the given key can be found in this map.
boolean	containsValue(java.lang.Object value) This method returns true, if the given value is a value of any entry in this map.
protected java.util.Map<K,Association<java.lang.Long,V>>	createEmptyMap() Provide a synchronized HashMap.
java.util.Set<java.util.Map.Entry<K,V>>	entrySet() This method automatically touches every entry, so that its expire period starts anew.
protected long	expirationTime()
protected void	expirationTime(long newValue)
protected java.util.Map.Entry<K,Association<java.lang.Long,V>>	findByValue(java.lang.Object value)
V	get(java.lang.Object key) Returns the object that was registered under the specified key.
protected java.util.Map<K,Association<java.lang.Long,V>>	internalMap()
protected void	internalMap(java.util.Map<K,Association<java.lang.Long,V>> newValue)
boolean	isEmpty()
protected boolean	isExpired(Association<java.lang.Long,V> assoc)
java.util.Set<K>	keySet() Returns all keys in this map.
protected java.lang.Long	newTimestamp()
V	put(K key, V value) Puts the given value under the specified key into the map.
void	putAll(java.util.Map<? extends K,? extends V> map) Each entry of the given map will be added.
V	remove(java.lang.Object key) Remove the entry with the given key and return the associated object.
protected void	removeExpiredEntries()
int	size()
protected void	touch(Association<java.lang.Long,V> assoc)
protected void	touchAll()
boolean	triggeredBy(Trigger trigger) FOR INTERNAL USE ONLY! Will be called by a Trigger to execute the clean-up of expired objects.
java.util.Collection<V>	values() Returns all values of the map.

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

TemporaryMap

protected TemporaryMap()

TemporaryMap

public TemporaryMap(long expiresAfterMs,
                    long checkAfterMs)

Initialize the new instance with values that define the expiration of any object in the map and the interval for checking if expired objects are in the map.

Parameters:

expiresAfterMs - Defines after what time (milliseconds) an unused object must be removed (must be >= 100)

checkAfterMs - Defines the interval for lookup and remove expired objects (must be >= 10)

Method Detail

clear

public void clear()

Specified by:

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

isEmpty

public boolean isEmpty()

Specified by:

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

size

public int size()

Specified by:

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

containsKey

public boolean containsKey(java.lang.Object key)

This method returns true, if the given key can be found in this map. If an entry with this key is found, its associated timestamp will be set anew, to ensure that any immediate call to get() still returns the object. Otherwise it could happen, that the object is already removed by the background process that checks the timestamps and expiration times.

Specified by:

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

See Also:

Map.containsKey(Object)

containsValue

public boolean containsValue(java.lang.Object value)

This method returns true, if the given value is a value of any entry in this map. If such an entry is found, its associated timestamp will be set anew, to ensure that any immediate call to get() still returns the object. Otherwise it could happen, that the object is already removed by the background process that checks the timestamps and expiration times.

Specified by:

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

See Also:

Map.containsValue(Object)

entrySet

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

This method automatically touches every entry, so that its expire period starts anew.

Specified by:

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

See Also:

Map.entrySet()

get

public V get(java.lang.Object key)

Returns the object that was registered under the specified key. Here this method also renews the timestamp associated with the key's entry. That is, the expiration time starts from 0 again.

Specified by:

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

See Also:

Map.get(Object)

keySet

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

Returns all keys in this map.
Resets the timestamp of all entries to ensure that the immediate usage of the returned keys with the get() method produce the associated values!

Specified by:

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

See Also:

Map.keySet()

put

public V put(K key,
             V value)

Puts the given value under the specified key into the map. It also associates a timestamp with this entry. Therefore it can be automatically removed after the defined expiration time.

Specified by:

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

See Also:

Map.put(Object, Object)

putAll

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

Each entry of the given map will be added. Each added entry gets an associated timestamp.

Specified by:

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

See Also:

Map.putAll(Map)

values

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

Returns all values of the map. With this method the timestamps of all entries in this map will be set anew. That means, their expiration time starts again at 0.

Specified by:

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

See Also:

Map.values()

remove

public V remove(java.lang.Object key)

Remove the entry with the given key and return the associated object.

Specified by:

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

Parameters:

key - The key of the entry to be removed

Returns:

The associated object or null if the key could not be found

canBeTriggeredBy

public boolean canBeTriggeredBy(Trigger trigger)

FOR INTERNAL USE ONLY!
Will be called by a Trigger to check if object clean-up can be executed.

Specified by:

canBeTriggeredBy in interface TriggerClient

Parameters:

trigger - The trigger that calls this method

Returns:

true, if the service method triggeredBy() can be called

See Also:

TriggerClient.canBeTriggeredBy(Trigger)

triggeredBy

public boolean triggeredBy(Trigger trigger)

FOR INTERNAL USE ONLY!
Will be called by a Trigger to execute the clean-up of expired objects.

Specified by:

triggeredBy in interface TriggerClient

Parameters:

trigger - The trigger that calls this method

Returns:

true, if the trigger should continue, otherwise false

See Also:

TriggerClient.triggeredBy(Trigger)

touch

protected void touch(Association<java.lang.Long,V> assoc)

touchAll

protected void touchAll()

newTimestamp

protected java.lang.Long newTimestamp()

removeExpiredEntries

protected void removeExpiredEntries()

isExpired

protected boolean isExpired(Association<java.lang.Long,V> assoc)

findByValue

protected java.util.Map.Entry<K,Association<java.lang.Long,V>> findByValue(java.lang.Object value)

createEmptyMap

protected java.util.Map<K,Association<java.lang.Long,V>> createEmptyMap()

Provide a synchronized HashMap.

internalMap

protected java.util.Map<K,Association<java.lang.Long,V>> internalMap()

internalMap

protected void internalMap(java.util.Map<K,Association<java.lang.Long,V>> newValue)

expirationTime

protected long expirationTime()

expirationTime

protected void expirationTime(long newValue)