org.cache2k.integration

Class ResiliencePolicy<K,V>

java.lang.Object

org.cache2k.integration.ResiliencePolicy<K,V>

All Implemented Interfaces:

ExpiryTimeValues

public abstract class ResiliencePolicy<K,V>
extends Object
implements ExpiryTimeValues

Controls how to deal with loader exceptions in a read through configuration. An exception can be cached and propagated or the cache can fallback to the currently cached value if a previous load attempt did complete successful.

Author:

Jens Wilke

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ResiliencePolicy.Context Provides additional context information.

Field Summary

Fields inherited from interface org.cache2k.expiry.ExpiryTimeValues

ETERNAL, NEUTRAL, NO_CACHE, NOW, REFRESH

Constructor Summary

Constructors

Constructor and Description
ResiliencePolicy()

Method Summary

Modifier and Type	Method and Description
void	init(ResiliencePolicy.Context context) Called before any other call.
abstract long	retryLoadAfter(K key, ExceptionInformation exceptionInformation) Called after the loader threw an exception and no previous value is available or suppressExceptionUntil(K, org.cache2k.integration.ExceptionInformation, org.cache2k.CacheEntry<K, V>) returned zero.
abstract long	suppressExceptionUntil(K key, ExceptionInformation exceptionInformation, CacheEntry<K,V> cachedContent) Called after the loader threw an exception and a previous value is available.

Methods inherited from class java.lang.Object

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

Constructor Detail

ResiliencePolicy

public ResiliencePolicy()

Method Detail

init

public void init(ResiliencePolicy.Context context)

Called before any other call.

Parameters:

context - Additional context information

suppressExceptionUntil

public abstract long suppressExceptionUntil(K key,
                                            ExceptionInformation exceptionInformation,
                                            CacheEntry<K,V> cachedContent)

Called after the loader threw an exception and a previous value is available. Determines from the given parameters whether the exception should be suppressed and the cache should return the last cached content.

The returned value is a point in time. If the currently cached content is expired, returning a future time will effectively extend the entry expiry.

Returning 0 or a past time means the exception should not be suppressed. The cache will call immediately retryLoadAfter(K, org.cache2k.integration.ExceptionInformation) to determine how long the exception should stay in the cache and when the next retry attempt takes place.

If the exception is not suppressed, it will wrapped into a CacheLoaderException and propagated to the cache client. This is customizable by the ExceptionPropagator.

Parameters:

cachedContent - The entry representing the currently cached content. It is possible that this data is already expired.

Returns:

Time in millis in the future when the content should expire again. A 0 or a time before the current time means the exception will not be suppressed. A ExpiryTimeValues.ETERNAL means the exception will be suppressed and the recent content will be returned eternally. If the returned time is after ExceptionInformation.getLoadTime() the exception will be suppressed for the ongoing operation.

retryLoadAfter

public abstract long retryLoadAfter(K key,
                                    ExceptionInformation exceptionInformation)

Called after the loader threw an exception and no previous value is available or suppressExceptionUntil(K, org.cache2k.integration.ExceptionInformation, org.cache2k.CacheEntry<K, V>) returned zero.