net.sf.ehcache.store
Interface Store

All Known Implementing Classes:

DiskStore, LruMemoryStore, MemoryStore, SyncAwareStore, XATransactionalStore

public interface Store

This is the interface for all stores. A store is a physical counterpart to a cache, which is a logical concept.

Version:

$Id: Store.java 1892 2010-02-18 07:27:25Z asingh $

Author:

Greg Luck

Method Summary

boolean	bufferFull() Some store types, such as the disk stores can fill their write buffers if puts come in too fast.
boolean	containsKey(java.lang.Object key) A check to see if a key is in the Store.
void	dispose() Prepares for shutdown.
void	expireElements() Expire all elements.
void	flush() Flush elements to persistent store.
Element	get(java.lang.Object key) Gets an item from the cache.
Policy	getEvictionPolicy()
java.lang.Object	getInternalContext() This should not be used, and will generally return null
java.lang.Object[]	getKeyArray() Gets an Array of the keys for all elements in the disk store.
Element	getQuiet(java.lang.Object key) Gets an Element from the Store, without updating statistics
int	getSize() Returns the current local store size
long	getSizeInBytes() Gets the size of the store, in bytes.
Status	getStatus() Returns the cache status.
int	getTerracottaClusteredSize() Returns the current Terracotta clustered store size
boolean	isCacheCoherent() Indicates whether this store provides a coherent view of all the elements in a cache.
boolean	isClusterCoherent() Returns true if the cache is in coherent mode cluster-wide.
boolean	isNodeCoherent() Returns true if the cache is in coherent mode for the current node.
boolean	put(Element element) Puts an item into the store.
boolean	putWithWriter(Element element, CacheWriterManager writerManager) Puts an item into the store and the cache writer manager in an atomic operation
Element	remove(java.lang.Object key) Removes an item from the cache.
void	removeAll() Remove all of the elements from the store.
Element	removeWithWriter(java.lang.Object key, CacheWriterManager writerManager) Removes an item from the store and the cache writer manager in an atomic operation.
void	setEvictionPolicy(Policy policy) Sets the eviction policy strategy.
void	setNodeCoherent(boolean coherent) Sets the cache in coherent or incoherent mode for the current node depending on the parameter.
void	waitUntilClusterCoherent() This method waits until the cache is in coherent mode in all the connected nodes.

Method Detail

put

boolean put(Element element)
            throws CacheException

Puts an item into the store.

Returns:

true if this is a new put for the key or element is null. Returns false if it was an update.

Throws:

CacheException

putWithWriter

boolean putWithWriter(Element element,
                      CacheWriterManager writerManager)
                      throws CacheException

Puts an item into the store and the cache writer manager in an atomic operation

Returns:

true if this is a new put for the key or element is null. Returns false if it was an update.

Throws:

CacheException

get

Element get(java.lang.Object key)

Gets an item from the cache.

getQuiet

Element getQuiet(java.lang.Object key)

Gets an Element from the Store, without updating statistics

Returns:

The element

getKeyArray

java.lang.Object[] getKeyArray()

Gets an Array of the keys for all elements in the disk store.

Returns:

An Object[] of Serializable keys

remove

Element remove(java.lang.Object key)

Removes an item from the cache.

Since:

signature changed in 1.2 from boolean to Element to support notifications

removeWithWriter

Element removeWithWriter(java.lang.Object key,
                         CacheWriterManager writerManager)
                         throws CacheException

Removes an item from the store and the cache writer manager in an atomic operation.

Throws:

CacheException

removeAll

void removeAll()
               throws CacheException

Remove all of the elements from the store.

If there are registered CacheEventListeners they are notified of the expiry or removal of the Element as each is removed.

Throws:

CacheException

dispose

void dispose()

Prepares for shutdown.

getSize

int getSize()

Returns the current local store size

Returns:

the count of the Elements in the Store on the local machine

getTerracottaClusteredSize

int getTerracottaClusteredSize()

Returns the current Terracotta clustered store size

Returns:

the count of the Elements in the Store across the cluster

getSizeInBytes

long getSizeInBytes()

Gets the size of the store, in bytes.

This method may be expensive to run, depending on implementation. Implementers may choose to return an approximate size.

Returns:

the approximate size of the store in bytes

getStatus

Status getStatus()

Returns the cache status.

containsKey

boolean containsKey(java.lang.Object key)

A check to see if a key is in the Store.

Parameters:

key - The Element key

Returns:

true if found. No check is made to see if the Element is expired. 1.2

expireElements

void expireElements()

Expire all elements.

flush

void flush()
           throws java.io.IOException

Flush elements to persistent store.

Throws:

java.io.IOException - if any IO error occurs

bufferFull

boolean bufferFull()

Some store types, such as the disk stores can fill their write buffers if puts come in too fast. The thread will wait for a short time before checking again.

Returns:

true if the store write buffer is backed up.

getEvictionPolicy

Policy getEvictionPolicy()

Returns:

the current eviction policy. This may not be the configured policy, if it has been dynamically set.

See Also:

setEvictionPolicy(Policy)

setEvictionPolicy

void setEvictionPolicy(Policy policy)

Sets the eviction policy strategy. The Store will use a policy at startup. The store may allow changing the eviction policy strategy dynamically. Otherwise implementations will throw an exception if this method is called.

Parameters:

policy - the new policy

getInternalContext

java.lang.Object getInternalContext()

This should not be used, and will generally return null

Returns:

some internal context (probably null)

isCacheCoherent

boolean isCacheCoherent()

Indicates whether this store provides a coherent view of all the elements in a cache. Note that this is same as calling isClusterCoherent() (introduced since 2.0) Use isNodeCoherent() to find out if the cache is coherent in the current node in the cluster

Returns:

true if the store is coherent; or false if the store potentially splits the cache storage with another store or isn't internally coherent

Since:

1.7

isClusterCoherent

boolean isClusterCoherent()

Returns true if the cache is in coherent mode cluster-wide. Returns false otherwise.

It applies to coherent clustering mechanisms only e.g. Terracotta

Returns:

true if the cache is in coherent mode cluster-wide, false otherwise

Since:

2.0

isNodeCoherent

boolean isNodeCoherent()

Returns true if the cache is in coherent mode for the current node. Returns false otherwise.

It applies to coherent clustering mechanisms only e.g. Terracotta

Returns:

true if the cache is in coherent mode cluster-wide, false otherwise

Since:

2.0

setNodeCoherent

void setNodeCoherent(boolean coherent)
                     throws java.lang.UnsupportedOperationException

Sets the cache in coherent or incoherent mode for the current node depending on the parameter. Calling setNodeCoherent(true) when the cache is already in coherent mode or calling setNodeCoherent(false) when already in incoherent mode will be a no-op.

It applies to coherent clustering mechanisms only e.g. Terracotta

Parameters:

coherent - true transitions to coherent mode, false to incoherent mode

Throws:

java.lang.UnsupportedOperationException - if this store does not support cache coherence, like RMI replication

Since:

2.0

waitUntilClusterCoherent

void waitUntilClusterCoherent()
                              throws java.lang.UnsupportedOperationException

This method waits until the cache is in coherent mode in all the connected nodes. If the cache is already in coherent mode it returns immediately

It applies to coherent clustering mechanisms only e.g. Terracotta

Throws:

java.lang.UnsupportedOperationException - if this store does not support cache coherence, like RMI replication

Since:

2.0