net.myrrix.common

Class ReloadingReference<V>

java.lang.Object

net.myrrix.common.ReloadingReference<V>

public final class ReloadingReference<V>
extends Object

Encapsulates a reference to something that is created the first time it is needed. Instead of providing an initial value, a Callable is given that can create the thing is provided. This can also periodically re-create or reload the value.

Author:

Sean Owen

Field Summary

Fields

Modifier and Type	Field and Description
static long	NO_RELOAD

Constructor Summary

Constructors

Constructor and Description
ReloadingReference(Callable<V> retriever)
ReloadingReference(Callable<V> retriever, long duration, TimeUnit timeUnit)

Method Summary

Methods

Modifier and Type	Method and Description
void	clear() Clears the reference, requiring a load on next access.
V	get()
V	get(long timeout, TimeUnit timeUnit) Like get(), but when a value already exists, will only wait for the given amount of time before just proceeding to return the existing value instead of waiting for a new value to load.
V	maybeGet()

Methods inherited from class java.lang.Object

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

Field Detail

NO_RELOAD

public static final long NO_RELOAD

See Also:

Constant Field Values

Constructor Detail

ReloadingReference

public ReloadingReference(Callable<V> retriever)

ReloadingReference

public ReloadingReference(Callable<V> retriever,
                  long duration,
                  TimeUnit timeUnit)

Parameters:

retriever - object that can supply a new, current value of the reference

duration - time after which a new value will be loaded, or NO_RELOAD to not reload after the initial value is loaded

timeUnit - units of time for duration

Method Detail

get

public V get(long timeout,
    TimeUnit timeUnit)

Like get(), but when a value already exists, will only wait for the given amount of time before just proceeding to return the existing value instead of waiting for a new value to load.

get

public V get()

Returns:

object that is returned by the provided Callable. If not yet created, it will block and wait for creation. If already created, it will return the existing value. The value will be re-created periodically, if the object has been configured to, and when this is needed, this method will again block while the value is re-created.

maybeGet

public V maybeGet()

Returns:

object that is returned by the provided Callable, if it has already been created previously, or null otherwise

clear

public void clear()

Clears the reference, requiring a load on next access.