Package org.cache2k.addon

Class CoalescingBulkLoader<K,V>

java.lang.Object

org.cache2k.addon.CoalescingBulkLoader<K,V>

All Implemented Interfaces:

AutoCloseable, org.cache2k.Customization, org.cache2k.DataAware<K,V>, org.cache2k.DataAwareCustomization<K,V>, org.cache2k.io.AsyncBulkCacheLoader<K,V>, org.cache2k.io.AsyncCacheLoader<K,V>

public class CoalescingBulkLoader<K,V>
extends Object
implements org.cache2k.io.AsyncBulkCacheLoader<K,V>, AutoCloseable

Wraps a AsyncBulkCacheLoader and combines (single) load requests into bulk requests. Usually a bulk load takes place, when a bulk operation, e.g. Cache.getAll(java.lang.Iterable<? extends K>) is issued. The cache core is producing no bulk requests take place for refresh, because every expiry is handled individually. This class coalesces requests into larger chunks.

Parameters: You may specify how long requests are being delayed and a maximum of loads coalesced into one batch.

Coalescing by default only happens for refresh ahead requests. This is controlled via the parameter refreshOnly. Requests that are not refresh ahead are client issued and executed immediately, together with any pending refresh ahead requests.

Usage: Either use the constructor CoalescingBulkLoader(AsyncBulkCacheLoader, long, int, boolean) and wrap a loader explicitly, or use the declarative configuration with CoalescingBulkLoaderSupport. If in doubt check the test cases.

Author:

Jens Wilke

Nested Class Summary

Nested classes/interfaces inherited from interface org.cache2k.io.AsyncBulkCacheLoader

org.cache2k.io.AsyncBulkCacheLoader.BulkCallback<K extends Object,V extends Object>, org.cache2k.io.AsyncBulkCacheLoader.BulkLoadContext<K extends Object,V extends Object>

Nested classes/interfaces inherited from interface org.cache2k.io.AsyncCacheLoader

org.cache2k.io.AsyncCacheLoader.Callback<V extends Object>, org.cache2k.io.AsyncCacheLoader.Context<K extends Object,V extends Object>

Constructor Summary

Constructors

Constructor	Description
CoalescingBulkLoader(org.cache2k.io.AsyncBulkCacheLoader<K,V> forwardingLoader, long maxDelayMillis, int maxBatchSize, boolean refreshOnly)	Constructor using the default time reference TimeReference.DEFAULT
CoalescingBulkLoader(org.cache2k.io.AsyncBulkCacheLoader<K,V> forwardingLoader, org.cache2k.operation.TimeReference timeReference, long maxDelayMillis, int maxBatchSize, boolean refreshOnly)	Constructor using the specified time reference instance.

Method Summary

Modifier and Type	Method	Description
void	close()
void	flush()	Send all pending requests to the loader.
boolean	forwardRequests(boolean timerEvent, boolean onlyWhenFull)	Gather requests up to max batch size and forward to the loader
long	getQueueSize()
void	loadAll(Set<K> keys, org.cache2k.io.AsyncBulkCacheLoader.BulkLoadContext<K,V> context, org.cache2k.io.AsyncBulkCacheLoader.BulkCallback<K,V> callback)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.cache2k.io.AsyncBulkCacheLoader

load

Constructor Detail

CoalescingBulkLoader

public CoalescingBulkLoader(org.cache2k.io.AsyncBulkCacheLoader<K,V> forwardingLoader,
                            long maxDelayMillis,
                            int maxBatchSize,
                            boolean refreshOnly)

Constructor using the default time reference TimeReference.DEFAULT

Parameters:

forwardingLoader - requests are forwarded to this loader

maxDelayMillis - see CoalescingBulkLoaderConfig.Builder.maxDelay(long, TimeUnit)

maxBatchSize - see CoalescingBulkLoaderConfig.Builder.maxBatchSize(int)

refreshOnly - see CoalescingBulkLoaderConfig.Builder.refreshOnly(boolean)

CoalescingBulkLoader

public CoalescingBulkLoader(org.cache2k.io.AsyncBulkCacheLoader<K,V> forwardingLoader,
                            org.cache2k.operation.TimeReference timeReference,
                            long maxDelayMillis,
                            int maxBatchSize,
                            boolean refreshOnly)

Constructor using the specified time reference instance.

Parameters:

timeReference - if the cache is using a different time reference, the instance is used to translate to milli seconds via TimeReference.ticksToMillisCeiling(long)

Method Detail

loadAll

public void loadAll(Set<K> keys,
                    org.cache2k.io.AsyncBulkCacheLoader.BulkLoadContext<K,V> context,
                    org.cache2k.io.AsyncBulkCacheLoader.BulkCallback<K,V> callback)

Specified by:

loadAll in interface org.cache2k.io.AsyncBulkCacheLoader<K,V>

flush

public void flush()

Send all pending requests to the loader. This is used for testing.

forwardRequests

public boolean forwardRequests(boolean timerEvent,
                               boolean onlyWhenFull)

Gather requests up to max batch size and forward to the loader

Parameters:

timerEvent - true for timer event, don't do anything if not due

onlyWhenFull - true for queue spill, double check within lock

Returns:

true if there might be more to process

getQueueSize

public long getQueueSize()

close

public void close()
           throws Exception

Specified by:

close in interface AutoCloseable

Throws:

Exception