org.codehaus.groovy.grails.web.util
Class CacheEntry<T>

java.lang.Object
  org.codehaus.groovy.grails.web.util.CacheEntry<T>

public class CacheEntry<T>
extends java.lang.Object

Wrapper for a value inside a cache that adds timestamp information for expiration and prevents "cache storms" with a Lock. JMM happens-before is ensured with AtomicReference. Objects in cache are assumed to not change after publication.

Field Summary

protected long	createdMillis
protected java.util.concurrent.atomic.AtomicReference<T>	valueRef
protected java.util.concurrent.locks.Lock	writeLock

Constructor Summary

CacheEntry(T value)

Method Summary

void	expire()
long	getCreatedMillis()
T	getValue()
T	getValue(long timeout, java.security.PrivilegedAction<T> updater) gets the current value from the entry and updates it if it's older than timeout updater is a callback for creating an updated value.
protected boolean	hasExpired(long timeout)
protected void	resetTimestamp()
protected boolean	shouldUpdate(long beforeLockingCreatedMillis)

Methods inherited from class java.lang.Object

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

Field Detail

valueRef

protected java.util.concurrent.atomic.AtomicReference<T> valueRef

createdMillis

protected long createdMillis

writeLock

protected java.util.concurrent.locks.Lock writeLock

Constructor Detail

CacheEntry

public CacheEntry(T value)

Method Detail

getValue

public T getValue(long timeout,
                  java.security.PrivilegedAction<T> updater)

gets the current value from the entry and updates it if it's older than timeout updater is a callback for creating an updated value.

Parameters:

timeout -

updater -

Returns:

The atomic reference

getValue

public T getValue()

hasExpired

protected boolean hasExpired(long timeout)

shouldUpdate

protected boolean shouldUpdate(long beforeLockingCreatedMillis)

resetTimestamp

protected void resetTimestamp()

getCreatedMillis

public long getCreatedMillis()

expire

public void expire()