net.sf.ehcache.store
Class CopyingCacheStore<T extends Store>

java.lang.Object
  net.sf.ehcache.store.CopyingCacheStore<T>

Type Parameters:

T - the store type it wraps

All Implemented Interfaces:

Store

public final class CopyingCacheStore<T extends Store>
extends Object
implements Store

Copies elements, either on read, write or both before using the underlying store to actually store things When copying both ways, the store might not see the same types being stored

Author:

Alex Snaps

Field Summary

Fields inherited from interface net.sf.ehcache.store.Store

CLUSTER_COHERENT, NODE_COHERENT

Constructor Summary

CopyingCacheStore(T store, boolean copyOnRead, boolean copyOnWrite, ReadWriteCopyStrategy<Element> copyStrategyInstance)
Creates a copying instance of store, that wraps the actual storage

Method Summary

void	addStoreListener(StoreListener listener) Add a listener to the store.
boolean	bufferFull() Some store types, such as the disk stores can fill their write buffers if puts come in too fast.
boolean	containsKey(Object key) A check to see if a key is in the Store.
boolean	containsKeyInMemory(Object key) A check to see if a key is in the Store and is currently held in memory.
boolean	containsKeyOffHeap(Object key) A check to see if a key is in the Store and is currently held off-heap.
boolean	containsKeyOnDisk(Object key) A check to see if a key is in the Store and is currently held on disk.
protected Element	copyElementForReadIfNeeded(Element element) Perform copy on read on an element if configured
protected Element	copyElementForWriteIfNeeded(Element element) Perform copy on write on an element if configured
void	dispose() Prepares for shutdown.
Results	executeQuery(StoreQuery query) Execute the given query on this store
void	expireElements() Expire all elements.
void	flush() Flush elements to persistent store.
Element	get(Object key) Gets an item from the cache.
Map<Object,Element>	getAll(Collection<?> keys) Retries the elements associated with a set of keys and update the statistics Keys which are not present in the cache will have null values associated with them in the returned map
Map<Object,Element>	getAllQuiet(Collection<?> keys) Retries the elements associated with a set of keys without updating the statistics Keys which are not present in the cache will have null values associated with them in the returned map
Policy	getInMemoryEvictionPolicy()
int	getInMemorySize() Returns the current local in-memory store size
long	getInMemorySizeInBytes() Gets the size of the in-memory portion of the store, in bytes.
Object	getInternalContext() This should not be used, and will generally return null
List	getKeys() Gets an Array of the keys for all elements in the disk store.
Object	getMBean() Optional implementation specific MBean exposed by the store.
int	getOffHeapSize() Returns the current local off-heap store size
long	getOffHeapSizeInBytes() Gets the size of the off-heap portion of the store, in bytes.
int	getOnDiskSize() Returns the current local on-disk store size
long	getOnDiskSizeInBytes() Gets the size of the on-disk portion of the store, in bytes.
Element	getQuiet(Object key) Gets an Element from the Store, without updating statistics
<T> Attribute<T>	getSearchAttribute(String attributeName) Retrieve the given named search attribute
int	getSize() Returns the current local store size
Status	getStatus() Returns the cache status.
int	getTerracottaClusteredSize() Returns the current Terracotta clustered store size
T	getUnderlyingStore() Accessor to the underlying store
boolean	hasAbortedSizeOf() Checks if the cache may contain elements for which the SizeOf engine gave up and only partially calculated the 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 e) Puts an item into the store.
void	putAll(Collection<Element> elements) Puts a collection of elements into the store.
Element	putIfAbsent(Element element) Put an element in the store if no element is currently mapped to the elements key.
boolean	putWithWriter(Element element, CacheWriterManager writerManager) Puts an item into the store and the cache writer manager in an atomic operation
void	recalculateSize(Object key) Recalculate size of the element mapped to the key
Element	remove(Object key) Removes an item from the cache.
void	removeAll() Remove all of the elements from the store.
void	removeAll(Collection<?> keys) Removes a collection of elements from the cache.
Element	removeElement(Element element, ElementValueComparator comparator) Remove the Element mapped to the key for the supplied element if the value of the supplied Element is equal to the value of the cached Element.
void	removeStoreListener(StoreListener listener) Remove listener from store.
Element	removeWithWriter(Object key, CacheWriterManager writerManager) Removes an item from the store and the cache writer manager in an atomic operation.
Element	replace(Element element) Replace the cached element only if an Element is currently cached for this key
boolean	replace(Element old, Element element, ElementValueComparator comparator) Replace the cached element only if the value of the current Element is equal to the value of the supplied old Element.
static boolean	requiresCopy(CacheConfiguration cacheConfiguration) Checks whether copying and hence wrapping is required
void	setAttributeExtractors(Map<String,AttributeExtractor> extractors) Inform this store of the configured attribute extractors.
void	setInMemoryEvictionPolicy(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.
static <T extends Store> CopyingCacheStore<T>	wrap(T cacheStore, CacheConfiguration cacheConfiguration) Wraps (always) with the proper configured CopyingCacheStore
static Store	wrapIfCopy(Store cacheStore, CacheConfiguration cacheConfiguration) Wraps the Store instance passed in, should any copy occur

Methods inherited from class java.lang.Object

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

Constructor Detail

CopyingCacheStore

public CopyingCacheStore(T store,
                         boolean copyOnRead,
                         boolean copyOnWrite,
                         ReadWriteCopyStrategy<Element> copyStrategyInstance)

Creates a copying instance of store, that wraps the actual storage

Parameters:

store - the real store

copyOnRead - whether to copy on reads

copyOnWrite - whether to copy on writes

copyStrategyInstance - the copy strategy to use on every copy operation

Method Detail

addStoreListener

public void addStoreListener(StoreListener listener)

Description copied from interface: Store

Add a listener to the store.

Specified by:

addStoreListener in interface Store

removeStoreListener

public void removeStoreListener(StoreListener listener)

Description copied from interface: Store

Remove listener from store.

Specified by:

removeStoreListener in interface Store

put

public boolean put(Element e)
            throws CacheException

Description copied from interface: Store

Puts an item into the store.

Specified by:

put in interface 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

putAll

public void putAll(Collection<Element> elements)
            throws CacheException

Description copied from interface: Store

Puts a collection of elements into the store.

Specified by:

putAll in interface Store

Parameters:

elements - Collection of elements to be put in the store

Throws:

CacheException

putWithWriter

public boolean putWithWriter(Element element,
                             CacheWriterManager writerManager)
                      throws CacheException

Description copied from interface: Store

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

Specified by:

putWithWriter in interface 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

get

public Element get(Object key)

Description copied from interface: Store

Gets an item from the cache.

Specified by:

get in interface Store

getQuiet

public Element getQuiet(Object key)

Description copied from interface: Store

Gets an Element from the Store, without updating statistics

Specified by:

getQuiet in interface Store

Returns:

The element

getKeys

public List getKeys()

Description copied from interface: Store

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

Specified by:

getKeys in interface Store

Returns:

An List of Serializable keys

remove

public Element remove(Object key)

Description copied from interface: Store

Removes an item from the cache.

Specified by:

remove in interface Store

removeAll

public void removeAll(Collection<?> keys)

Description copied from interface: Store

Removes a collection of elements from the cache.

Specified by:

removeAll in interface Store

removeWithWriter

public Element removeWithWriter(Object key,
                                CacheWriterManager writerManager)
                         throws CacheException

Description copied from interface: Store

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

Specified by:

removeWithWriter in interface Store

Throws:

CacheException

removeAll

public void removeAll()
               throws CacheException

Description copied from interface: Store

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.

Specified by:

removeAll in interface Store

Throws:

CacheException

putIfAbsent

public Element putIfAbsent(Element element)
                    throws NullPointerException

Description copied from interface: Store

Put an element in the store if no element is currently mapped to the elements key.

Specified by:

putIfAbsent in interface Store

Parameters:

element - element to be added

Returns:

the element previously cached for this key, or null if none.

Throws:

NullPointerException - if the element is null, or has a null key

removeElement

public Element removeElement(Element element,
                             ElementValueComparator comparator)
                      throws NullPointerException

Description copied from interface: Store

Remove the Element mapped to the key for the supplied element if the value of the supplied Element is equal to the value of the cached Element. This is a CAS operation. It is consistent even against a distributed cache that is not coherent. If the old value is stale when this operation is attempted the remove does not take place.

Specified by:

removeElement in interface Store

Parameters:

element - Element to be removed

comparator - ElementValueComparator to use to compare elements

Returns:

the Element removed or null if no Element was removed

Throws:

NullPointerException - if the element is null, or has a null key

replace

public boolean replace(Element old,
                       Element element,
                       ElementValueComparator comparator)
                throws NullPointerException,
                       IllegalArgumentException

Description copied from interface: Store

Replace the cached element only if the value of the current Element is equal to the value of the supplied old Element.

Specified by:

replace in interface Store

Parameters:

old - Element to be test against

element - Element to be cached

comparator - ElementValueComparator to use to compare elements

Returns:

true is the Element was replaced

Throws:

NullPointerException - if the either Element is null or has a null key

IllegalArgumentException - if the two Element keys are non-null but not equal

replace

public Element replace(Element element)
                throws NullPointerException

Description copied from interface: Store

Replace the cached element only if an Element is currently cached for this key

Specified by:

replace in interface Store

Parameters:

element - Element to be cached

Returns:

the Element previously cached for this key, or null if no Element was cached

Throws:

NullPointerException - if the Element is null or has a null key

dispose

public void dispose()

Description copied from interface: Store

Prepares for shutdown.

Specified by:

dispose in interface Store

getSize

public int getSize()

Description copied from interface: Store

Returns the current local store size

Specified by:

getSize in interface Store

Returns:

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

getInMemorySize

public int getInMemorySize()

Description copied from interface: Store

Returns the current local in-memory store size

Specified by:

getInMemorySize in interface Store

Returns:

the count of the Elements in the Store and in-memory on the local machine

getOffHeapSize

public int getOffHeapSize()

Description copied from interface: Store

Returns the current local off-heap store size

Specified by:

getOffHeapSize in interface Store

Returns:

the count of the Elements in the Store and off-heap on the local machine

getOnDiskSize

public int getOnDiskSize()

Description copied from interface: Store

Returns the current local on-disk store size

Specified by:

getOnDiskSize in interface Store

Returns:

the count of the Elements in the Store and on-disk on the local machine

getTerracottaClusteredSize

public int getTerracottaClusteredSize()

Description copied from interface: Store

Returns the current Terracotta clustered store size

Specified by:

getTerracottaClusteredSize in interface Store

Returns:

the count of the Elements in the Store across the cluster

getInMemorySizeInBytes

public long getInMemorySizeInBytes()

Description copied from interface: Store

Gets the size of the in-memory portion of the store, in bytes.

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

Specified by:

getInMemorySizeInBytes in interface Store

Returns:

the approximate in-memory size of the store in bytes

getOffHeapSizeInBytes

public long getOffHeapSizeInBytes()

Description copied from interface: Store

Gets the size of the off-heap portion of the store, in bytes.

Specified by:

getOffHeapSizeInBytes in interface Store

Returns:

the approximate off-heap size of the store in bytes

getOnDiskSizeInBytes

public long getOnDiskSizeInBytes()

Description copied from interface: Store

Gets the size of the on-disk portion of the store, in bytes.

Specified by:

getOnDiskSizeInBytes in interface Store

Returns:

the on-disk size of the store in bytes

hasAbortedSizeOf

public boolean hasAbortedSizeOf()

Description copied from interface: Store

Checks if the cache may contain elements for which the SizeOf engine gave up and only partially calculated the size.

Specified by:

hasAbortedSizeOf in interface Store

Returns:

true if at least one partially sized element may be in the cache

getStatus

public Status getStatus()

Description copied from interface: Store

Returns the cache status.

Specified by:

getStatus in interface Store

containsKey

public boolean containsKey(Object key)

Description copied from interface: Store

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

Specified by:

containsKey in interface Store

Parameters:

key - The Element key

Returns:

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

containsKeyOnDisk

public boolean containsKeyOnDisk(Object key)

Description copied from interface: Store

A check to see if a key is in the Store and is currently held on disk.

Specified by:

containsKeyOnDisk in interface Store

Parameters:

key - The Element key

Returns:

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

containsKeyOffHeap

public boolean containsKeyOffHeap(Object key)

Description copied from interface: Store

A check to see if a key is in the Store and is currently held off-heap.

Specified by:

containsKeyOffHeap in interface Store

Parameters:

key - The Element key

Returns:

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

containsKeyInMemory

public boolean containsKeyInMemory(Object key)

Description copied from interface: Store

A check to see if a key is in the Store and is currently held in memory.

Specified by:

containsKeyInMemory in interface Store

Parameters:

key - The Element key

Returns:

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

expireElements

public void expireElements()

Description copied from interface: Store

Expire all elements.

Specified by:

expireElements in interface Store

flush

public void flush()
           throws IOException

Description copied from interface: Store

Flush elements to persistent store.

Specified by:

flush in interface Store

Throws:

IOException - if any IO error occurs

bufferFull

public boolean bufferFull()

Description copied from interface: Store

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.

Specified by:

bufferFull in interface Store

Returns:

true if the store write buffer is backed up.

getInMemoryEvictionPolicy

public Policy getInMemoryEvictionPolicy()

Specified by:

getInMemoryEvictionPolicy in interface Store

Returns:

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

See Also:

Store.setInMemoryEvictionPolicy(Policy)

setInMemoryEvictionPolicy

public void setInMemoryEvictionPolicy(Policy policy)

Description copied from interface: Store

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.

Specified by:

setInMemoryEvictionPolicy in interface Store

Parameters:

policy - the new policy

getInternalContext

public Object getInternalContext()

Description copied from interface: Store

This should not be used, and will generally return null

Specified by:

getInternalContext in interface Store

Returns:

some internal context (probably null)

isCacheCoherent

public boolean isCacheCoherent()

Description copied from interface: Store

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

Specified by:

isCacheCoherent in interface Store

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

isClusterCoherent

public boolean isClusterCoherent()
                          throws TerracottaNotRunningException

Description copied from interface: Store

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

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

Specified by:

isClusterCoherent in interface Store

Returns:

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

Throws:

TerracottaNotRunningException

isNodeCoherent

public boolean isNodeCoherent()
                       throws TerracottaNotRunningException

Description copied from interface: Store

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

Specified by:

isNodeCoherent in interface Store

Returns:

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

Throws:

TerracottaNotRunningException

setNodeCoherent

public void setNodeCoherent(boolean coherent)
                     throws UnsupportedOperationException,
                            TerracottaNotRunningException

Description copied from interface: Store

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

Specified by:

setNodeCoherent in interface Store

Parameters:

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

Throws:

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

TerracottaNotRunningException

waitUntilClusterCoherent

public void waitUntilClusterCoherent()
                              throws UnsupportedOperationException,
                                     TerracottaNotRunningException,
                                     InterruptedException

Description copied from interface: Store

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

Specified by:

waitUntilClusterCoherent in interface Store

Throws:

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

InterruptedException

TerracottaNotRunningException

getMBean

public Object getMBean()

Description copied from interface: Store

Optional implementation specific MBean exposed by the store.

Specified by:

getMBean in interface Store

Returns:

implementation specific management bean

setAttributeExtractors

public void setAttributeExtractors(Map<String,AttributeExtractor> extractors)

Description copied from interface: Store

Inform this store of the configured attribute extractors. Stores that will not invoke extractors are free to ignore this call

Specified by:

setAttributeExtractors in interface Store

executeQuery

public Results executeQuery(StoreQuery query)
                     throws SearchException

Description copied from interface: Store

Execute the given query on this store

Specified by:

executeQuery in interface Store

Parameters:

query - query to execute

Returns:

query results

Throws:

SearchException

getSearchAttribute

public <T> Attribute<T> getSearchAttribute(String attributeName)

Description copied from interface: Store

Retrieve the given named search attribute

Specified by:

getSearchAttribute in interface Store

Type Parameters:

T - type of the attribute

Parameters:

attributeName - the name of the attribute to retrieve

Returns:

the search attribute or null if non-existent

getAllQuiet

public Map<Object,Element> getAllQuiet(Collection<?> keys)

Description copied from interface: Store

Retries the elements associated with a set of keys without updating the statistics Keys which are not present in the cache will have null values associated with them in the returned map

Specified by:

getAllQuiet in interface Store

Parameters:

keys - a collection of keys to look for

Returns:

a map of keys and their corresponding values

getAll

public Map<Object,Element> getAll(Collection<?> keys)

Description copied from interface: Store

Retries the elements associated with a set of keys and update the statistics Keys which are not present in the cache will have null values associated with them in the returned map

Specified by:

getAll in interface Store

Parameters:

keys - a collection of keys to look for

Returns:

a map of keys and their corresponding values

recalculateSize

public void recalculateSize(Object key)

Description copied from interface: Store

Recalculate size of the element mapped to the key

Specified by:

recalculateSize in interface Store

Parameters:

key - the key

getUnderlyingStore

public T getUnderlyingStore()

Accessor to the underlying store

Returns:

the underlying store

copyElementForReadIfNeeded

protected Element copyElementForReadIfNeeded(Element element)

Perform copy on read on an element if configured

Parameters:

element - the element to copy for read

Returns:

a copy of the element with the reconstructed original value

copyElementForWriteIfNeeded

protected Element copyElementForWriteIfNeeded(Element element)

Perform copy on write on an element if configured

Parameters:

element - the element to copy for write

Returns:

a copy of the element with a storage-ready value

wrapIfCopy

public static Store wrapIfCopy(Store cacheStore,
                               CacheConfiguration cacheConfiguration)

Wraps the Store instance passed in, should any copy occur

Parameters:

cacheStore - the store

cacheConfiguration - the cache config for that store

Returns:

the wrapped Store if copying is required, or the Store instance passed in

wrap

public static <T extends Store> CopyingCacheStore<T> wrap(T cacheStore,
                                                          CacheConfiguration cacheConfiguration)

Wraps (always) with the proper configured CopyingCacheStore

Type Parameters:

T - the Store type

Parameters:

cacheStore - the store to wrap

cacheConfiguration - the cache config backed by this store

Returns:

the wrapped store

requiresCopy

public static boolean requiresCopy(CacheConfiguration cacheConfiguration)

Checks whether copying and hence wrapping is required

Parameters:

cacheConfiguration - the cache config

Returns:

true is copying is required, otherwise false