org.jmxtrans.agent.util

Class CachingReference<E>

java.lang.Object

org.jmxtrans.agent.util.CachingReference<E>

public abstract class CachingReference<E>
extends java.lang.Object

Maintains a cached version of the Object that it holds and handle the renewal of this object upon expiration. Greatly inspired by the CachedData sample provided in the javadoc of ReentrantReadWriteLock. Object is created implementing the newObject() method. Sample to get an InetAddress refreshed against a DNS every 10 seconds:

 CachingReference myRemoteServerAddress = new CachingReference<InetAddress>(10, TimeUnit.SECONDS) {
     protected InetAddress newObject() {
         try {
             return InetAddress.getByName(myRemoteServerHostname);
         } catch () {
             throw new RuntimeException("Exception resolving '" + myRemoteServerHostname + "'", e);
         }
     }
 }
 

Author:

Cyrille Le Clerc

Constructor Summary

Constructors

Constructor and Description
CachingReference(long timeToLiveInNanos)
CachingReference(long timeToLive, java.util.concurrent.TimeUnit timeToLiveUnit)

Method Summary

Modifier and Type	Method and Description
E	get()
protected abstract E	newObject()
void	purge() Purge the cached reference so that a new object will be created for the next get()
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

CachingReference

public CachingReference(long timeToLiveInNanos)

CachingReference

public CachingReference(long timeToLive,
                        java.util.concurrent.TimeUnit timeToLiveUnit)

Method Detail

newObject

@Nullable
protected abstract E newObject()

Returns:

the newly created object.

get

@Nullable
public E get()

Returns:

the up to date version of the Object hold by this reference.

purge

public void purge()

Purge the cached reference so that a new object will be created for the next get()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object