org.cache2k.storage

Class ByReferenceHeapStorageImpl

java.lang.Object

org.cache2k.storage.ByReferenceHeapStorageImpl

All Implemented Interfaces:

CacheStorage

public class ByReferenceHeapStorageImpl
extends Object
implements CacheStorage

Simple storage implementation, just uses a hashmap. Usable for testing and as a tiny storage implementation example.

Author:

Jens Wilke; created: 2014-06-21

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ByReferenceHeapStorageImpl.Provider

Nested classes/interfaces inherited from interface org.cache2k.storage.CacheStorage

CacheStorage.EntryFilter, CacheStorage.EntryVisitor, CacheStorage.MultiThreadedContext, CacheStorage.VisitContext

Constructor Summary

Constructors

Constructor and Description
ByReferenceHeapStorageImpl()

Method Summary

Methods

Modifier and Type	Method and Description
void	clear() Remove all entries from the cache and free resources.
void	close() Free all resources and stop operations immediately.
boolean	contains(Object key) Returns true if there is a mapping for the key.
StorageEntry	get(Object key) Retrieve the entry from the storage.
int	getEntryCount()
void	open(CacheStorageContext ctx, StorageConfiguration<Void> cfg)
void	put(StorageEntry e) Stores the entry in the storage.
boolean	remove(Object key)
void	visit(CacheStorage.VisitContext ctx, CacheStorage.EntryFilter f, CacheStorage.EntryVisitor v) Iterate over all stored entries and call the entry visitor.

Methods inherited from class java.lang.Object

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

Constructor Detail

ByReferenceHeapStorageImpl

public ByReferenceHeapStorageImpl()

Method Detail

open

public void open(CacheStorageContext ctx,
        StorageConfiguration<Void> cfg)

get

public StorageEntry get(Object key)
                 throws Exception

Description copied from interface: CacheStorage

Retrieve the entry from the storage. If there is no mapping for the key, null is returned.

Depending on the cache configuration, an exception on get is not severe. The cache will try other sources or return null.

Specified by:

get in interface CacheStorage

Throws:

Exception

put

public void put(StorageEntry e)
         throws Exception

Description copied from interface: CacheStorage

Stores the entry in the storage. The entry instance is solely for transferring the data, no reference may be hold within the storage to it. The callee takes care that the entry data is consistent during the put method call.

If a put operation fails an implementation should try to remove an existing entry bound to the key and then throw the exception.

Specified by:

put in interface CacheStorage

Throws:

IOException - may be thrown if hope is lost

Exception

remove

public boolean remove(Object key)
               throws Exception

Specified by:

remove in interface CacheStorage

Throws:

Exception

contains

public boolean contains(Object key)
                 throws Exception

Description copied from interface: CacheStorage

Returns true if there is a mapping for the key.

An exception on contains is not severe. The cache will try other sources or return null.

Specified by:

contains in interface CacheStorage

Throws:

Exception

clear

public void clear()
           throws Exception

Description copied from interface: CacheStorage

Remove all entries from the cache and free resources. This operation is called when there is no other operation concurrently executed on this storage instance.

When a Cache.clear() is initiated there is no obligation to send a CacheStorage.clear() to the persisted storage. Alternatively, all objects can be removed via remove().

Specified by:

clear in interface CacheStorage

Throws:

Exception

close

public void close()
           throws Exception

Description copied from interface: CacheStorage

Free all resources and stop operations immediately.

Specified by:

close in interface CacheStorage

Throws:

Exception

visit

public void visit(CacheStorage.VisitContext ctx,
         CacheStorage.EntryFilter f,
         CacheStorage.EntryVisitor v)
           throws Exception

Description copied from interface: CacheStorage

Iterate over all stored entries and call the entry visitor. It is generally safe to return expired entries. If PurgeableStorage is not implemented, returning expired entries is a must, to support the generic purge algorithm.

If the ExecutorService is used, the method may return immediately without the waiting for all threads to finish. This is done by the caller, when needed.

Specified by:

visit in interface CacheStorage

Throws:

Exception

getEntryCount

public int getEntryCount()

Specified by:

getEntryCount in interface CacheStorage