com.oracle.bmc.hdfs.caching

Class CachingObjectStorage.Handler

java.lang.Object

com.oracle.bmc.hdfs.caching.CachingObjectStorage.Handler

All Implemented Interfaces:

InvocationHandler

Enclosing interface:

CachingObjectStorage

public static class CachingObjectStorage.Handler
extends Object
implements InvocationHandler

Implemented as proxy/invocation handler, so we don't have to add more and more methods that just client to the inner ObjectStorage instance. This will continue to work, even as new methods are added to the interface.

Constructor Summary

Constructors

Constructor and Description

Handler(com.oracle.bmc.objectstorage.ObjectStorage client, com.oracle.bmc.objectstorage.transfer.DownloadConfiguration downloadConfiguration, Path cacheDirectory, ExecutorService downloadExecutor, CachingObjectStorage.UncacheablePredicate uncacheablePredicate, ConsistencyPolicy consistencyPolicy, CacheBuilder<CachingObjectStorage.GetObjectRequestCacheKey,CachingObjectStorage.GetObjectResponseCacheValue,?> cacheBuilder, ExecutorService deletionExecutor, CachingObjectStorage.RowLockProvider rowLockProvider, Runnable cacheGarbageCollection) Create an ObjectStorage client that caches the contents returned by ObjectStorage.getObject(GetObjectRequest) on disk.

Method Summary

Modifier and Type	Method and Description
protected void	cleanUp() Performs cache clean-up, i.e.
protected void	close()
protected Cache.Statistics	getCacheStatistics() Return the statistics for the getObject cache.
protected Set<Path>	getEvictedButNotDeleted() Returns a read-only set of paths to files that have been evicted but not deleted yet, since they are still being read.
protected com.oracle.bmc.objectstorage.responses.GetObjectResponse	getObject(com.oracle.bmc.objectstorage.requests.GetObjectRequest getObjectRequest)
protected com.oracle.bmc.objectstorage.responses.GetObjectResponse	getObjectUncached(com.oracle.bmc.objectstorage.requests.GetObjectRequest getObjectRequest) Get the object, circumventing the cache.
protected Set<? extends PhantomReference>	getPhantomReferences() For debug purposes, returns a read-only set of phantom references for the cached items.
Object	invoke(Object proxy, Method method, Object[] args)
protected void	prepopulateCache(com.oracle.bmc.objectstorage.requests.GetObjectRequest cacheRequest, com.oracle.bmc.objectstorage.responses.GetObjectResponse cacheResponse) Populates the cache at the request with the given response.

Methods inherited from class java.lang.Object

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

Constructor Detail

Handler

public Handler(com.oracle.bmc.objectstorage.ObjectStorage client,
               com.oracle.bmc.objectstorage.transfer.DownloadConfiguration downloadConfiguration,
               Path cacheDirectory,
               ExecutorService downloadExecutor,
               CachingObjectStorage.UncacheablePredicate uncacheablePredicate,
               ConsistencyPolicy consistencyPolicy,
               CacheBuilder<CachingObjectStorage.GetObjectRequestCacheKey,CachingObjectStorage.GetObjectResponseCacheValue,?> cacheBuilder,
               ExecutorService deletionExecutor,
               CachingObjectStorage.RowLockProvider rowLockProvider,
               Runnable cacheGarbageCollection)

Create an ObjectStorage client that caches the contents returned by ObjectStorage.getObject(GetObjectRequest) on disk.

Parameters:

client - ObjectStorage client

downloadConfiguration - DownloadConfiguration to use for downloading

cacheDirectory - directory where the cache is stored

downloadExecutor - executor for providing the threads in which objects will be downloaded to the cache

uncacheablePredicate - predicate that decides if a request cannot be cached

consistencyPolicy - controls eviction of conflicting items

cacheBuilder - cache builder to control size and eviction

deletionExecutor - for creating a thread that deletes evicted files after they are not being read anymore

rowLockProvider - provider for row locks

cacheGarbageCollection - runnable to be executed when there is a cache update

Method Detail

invoke

public Object invoke(Object proxy,
                     Method method,
                     Object[] args)
              throws Throwable

Specified by:

invoke in interface InvocationHandler

Throws:

Throwable

getObject

protected com.oracle.bmc.objectstorage.responses.GetObjectResponse getObject(com.oracle.bmc.objectstorage.requests.GetObjectRequest getObjectRequest)

prepopulateCache

protected void prepopulateCache(com.oracle.bmc.objectstorage.requests.GetObjectRequest cacheRequest,
                                com.oracle.bmc.objectstorage.responses.GetObjectResponse cacheResponse)

Populates the cache at the request with the given response.

Parameters:

cacheRequest - request entry to fill.

cacheResponse - content to be put at the cache entry.

getObjectUncached

protected com.oracle.bmc.objectstorage.responses.GetObjectResponse getObjectUncached(com.oracle.bmc.objectstorage.requests.GetObjectRequest getObjectRequest)

Get the object, circumventing the cache.

Parameters:

getObjectRequest - request

Returns:

response

cleanUp

protected void cleanUp()

Performs cache clean-up, i.e. evictions. This evicts items from the cache to make sure the cache matches expiration times and, to a lesser degree, size and weight constraints. Size and weight constraints may not be matched immediately, since this method does not automatically delete cached files from disk if they are still being read. The files cached on disk will only be cleaned up once all streams currently reading them have been closed. Calling this method is optional. This kind of clean-up is also performed whenever ObjectStorage.getObject(GetObjectRequest) operations are performed, but in absence of such activity, this method can be used to trigger clean-up on-demand.

getEvictedButNotDeleted

protected Set<Path> getEvictedButNotDeleted()

Returns a read-only set of paths to files that have been evicted but not deleted yet, since they are still being read.

Returns:

read-only set of paths to files that have been evicted but not yet deleted

getPhantomReferences

protected Set<? extends PhantomReference> getPhantomReferences()

For debug purposes, returns a read-only set of phantom references for the cached items.

Returns:

set of phantom references

getCacheStatistics

protected Cache.Statistics getCacheStatistics()

Return the statistics for the getObject cache.

Returns:

getObject cache statistics

close

protected void close()
              throws Exception

Throws:

Exception