net.sf.ehcache.store.disk
Class DiskStore

java.lang.Object
  net.sf.ehcache.store.AbstractStore
      net.sf.ehcache.store.disk.DiskStore

All Implemented Interfaces:

AuthoritativeTier, Store, StripedReadWriteLockProvider

public final class DiskStore
extends AbstractStore
implements StripedReadWriteLockProvider, AuthoritativeTier

Implements a persistent-to-disk store.

All new elements are automatically scheduled for writing to disk.

Author:

Chris Dennis, Ludovic Orban

Field Summary

Fields inherited from class net.sf.ehcache.store.AbstractStore

attributeExtractors

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

CLUSTER_COHERENT, NODE_COHERENT

Method Summary

boolean	bufferFull() Some store types, such as the disk stores can fill their write buffers if puts come in too fast.
void	changeDiskCapacity(int newCapacity) Change the disk capacity, in number of elements
void	clearFaultedBit() Marks all entries has flushed (i.e.
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.
static DiskStore	create(Cache cache) Creates a persitent-to-disk store for the given cache, using the given disk path.
static DiskStore	create(Ehcache cache, Pool onHeapPool, Pool onDiskPool) Creates a persitent-to-disk store for the given cache, using the given disk path.
static Store	createCacheStore(Ehcache cache, Pool onHeapPool, Pool onDiskPool) Create a DiskBackedMemoryStore instance
StripedReadWriteLock	createStripedReadWriteLock() Will create a StripedReadWriteLock always using the same spreading function
void	dispose() Prepares for shutdown.
boolean	evict(Object key, DiskStorageFactory.DiskSubstitute substitute) Remove the matching mapping.
Element	evictElement(Object key, DiskStorageFactory.DiskSubstitute substitute) Remove the matching mapping.
void	expireElements() Expire all elements.
Element	fault(Object key, boolean updateStats) Marks the entry as not evictable and returns it atomically
boolean	fault(Object key, net.sf.ehcache.store.disk.DiskStorageFactory.Placeholder expect, DiskStorageFactory.DiskMarker fault) Atomically switch (CAS) the expect representation of this element for the fault representation.
void	flush() Flush elements to persistent store.
boolean	flush(Element element) This marks the entry as evictable again and updates relevant access stats
Element	get(Object key) Gets an item from the cache.
File	getDataFile() Return a reference to the data file backing this store.
File	getIndexFile() Return a reference to the index file for this store.
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
List<DiskStorageFactory.DiskSubstitute>	getRandomSample(ElementSubstituteFilter factory, int sampleSize, Object keyHint) Select a random sample of elements generated by the supplied factory.
int	getSize() Returns the current local store size
Status	getStatus() Returns the cache status.
int	getTerracottaClusteredSize() Returns the current Terracotta clustered store size
boolean	isFaulted(Object key) Verifies if the mapping for a key is marked as faulted
Set<Object>	keySet() Get a set view of the keys in this store
boolean	put(Element element) Puts an item into the store.
boolean	putFaulted(Element element) Stupid "implicit" contract in tests that dictates that entries put, will be in highest tier!
Element	putIfAbsent(Element element) Put an element in the store if no element is currently mapped to the elements key.
boolean	putRawIfAbsent(Object key, DiskStorageFactory.DiskMarker encoded) Put the given encoded element directly 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(Object key) Removes an item from the cache.
void	removeAll() Remove all of the elements from the store.
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.
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.
void	setInMemoryEvictionPolicy(Policy policy) Sets the eviction policy strategy.
Object	unretrievedGet(Object key) Return the unretrieved (undecoded) value for this key

Methods inherited from class net.sf.ehcache.store.AbstractStore

addStoreListener, executeQuery, getAll, getAllQuiet, getEventListenerList, getSearchAttribute, hasAbortedSizeOf, isCacheCoherent, isClusterCoherent, isNodeCoherent, putAll, recalculateSize, removeAll, removeStoreListener, setAttributeExtractors, setNodeCoherent, waitUntilClusterCoherent

Methods inherited from class java.lang.Object

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

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

addStoreListener, executeQuery, getAll, getAllQuiet, getSearchAttribute, hasAbortedSizeOf, isCacheCoherent, isClusterCoherent, isNodeCoherent, putAll, recalculateSize, removeAll, removeStoreListener, setAttributeExtractors, setNodeCoherent, waitUntilClusterCoherent

Method Detail

create

public static DiskStore create(Ehcache cache,
                               Pool onHeapPool,
                               Pool onDiskPool)

Creates a persitent-to-disk store for the given cache, using the given disk path.

Parameters:

cache - cache that fronts this store

onHeapPool - pool to track heap usage

onDiskPool - pool to track disk usage

Returns:

a fully initialized store

create

public static DiskStore create(Cache cache)

Creates a persitent-to-disk store for the given cache, using the given disk path. Heap and disk usage are not tracked by the returned store.

Parameters:

cache - cache that fronts this store

Returns:

a fully initialized store

createCacheStore

public static Store createCacheStore(Ehcache cache,
                                     Pool onHeapPool,
                                     Pool onDiskPool)

Create a DiskBackedMemoryStore instance

Parameters:

cache - the cache

onHeapPool - the pool tracking on-heap usage

onDiskPool - the pool tracking on-disk usage

Returns:

a DiskBackedMemoryStore instance

createStripedReadWriteLock

public StripedReadWriteLock createStripedReadWriteLock()

Will create a StripedReadWriteLock always using the same spreading function

Specified by:

createStripedReadWriteLock in interface StripedReadWriteLockProvider

Returns:

a newly created StripedReadWriteLock

fault

public Element fault(Object key,
                     boolean updateStats)

Description copied from interface: AuthoritativeTier

Marks the entry as not evictable and returns it atomically

Specified by:

fault in interface AuthoritativeTier

Returns:

putFaulted

public boolean putFaulted(Element element)

Description copied from interface: AuthoritativeTier

Stupid "implicit" contract in tests that dictates that entries put, will be in highest tier!

Specified by:

putFaulted in interface AuthoritativeTier

Returns:

flush

public boolean flush(Element element)

Description copied from interface: AuthoritativeTier

This marks the entry as evictable again and updates relevant access stats

Specified by:

flush in interface AuthoritativeTier

Returns:

isFaulted

public boolean isFaulted(Object key)

Verifies if the mapping for a key is marked as faulted

Parameters:

key - the key to check the mapping for

Returns:

true if faulted, false otherwise (including no mapping)

changeDiskCapacity

public void changeDiskCapacity(int newCapacity)

Change the disk capacity, in number of elements

Parameters:

newCapacity - the new max elements on disk

bufferFull

public 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.

Specified by:

bufferFull in interface Store

Returns:

true if the store write buffer is backed up.

containsKeyInMemory

public boolean containsKeyInMemory(Object key)

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.

containsKeyOffHeap

public boolean containsKeyOffHeap(Object key)

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.

containsKeyOnDisk

public boolean containsKeyOnDisk(Object key)

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.

expireElements

public void expireElements()

Expire all elements.

Specified by:

expireElements in interface Store

flush

public void flush()
           throws IOException

Flush elements to persistent store.

Specified by:

flush in interface Store

Throws:

IOException - if any IO error occurs

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)

getInMemorySize

public int getInMemorySize()

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

getInMemorySizeInBytes

public long getInMemorySizeInBytes()

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

getOffHeapSize

public int getOffHeapSize()

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

getOffHeapSizeInBytes

public long getOffHeapSizeInBytes()

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

getOnDiskSize

public int getOnDiskSize()

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

getOnDiskSizeInBytes

public long getOnDiskSizeInBytes()

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

getTerracottaClusteredSize

public int getTerracottaClusteredSize()

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

setInMemoryEvictionPolicy

public void setInMemoryEvictionPolicy(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.

Specified by:

setInMemoryEvictionPolicy in interface Store

Parameters:

policy - the new policy

getDataFile

public File getDataFile()

Return a reference to the data file backing this store.

Returns:

a reference to the data file backing this store.

getIndexFile

public File getIndexFile()

Return a reference to the index file for this store.

Returns:

a reference to the index file for this store.

getMBean

public Object getMBean()

Optional implementation specific MBean exposed by the store.

Specified by:

getMBean in interface Store

Returns:

implementation specific management bean

put

public boolean put(Element element)

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.

putWithWriter

public boolean putWithWriter(Element element,
                             CacheWriterManager writerManager)

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.

get

public Element get(Object key)

Gets an item from the cache.

Specified by:

get in interface Store

getQuiet

public Element getQuiet(Object key)

Gets an Element from the Store, without updating statistics

Specified by:

getQuiet in interface Store

Returns:

The element

unretrievedGet

public Object unretrievedGet(Object key)

Return the unretrieved (undecoded) value for this key

Parameters:

key - key to lookup

Returns:

Element or ElementSubstitute

putRawIfAbsent

public boolean putRawIfAbsent(Object key,
                              DiskStorageFactory.DiskMarker encoded)
                       throws IllegalArgumentException

Put the given encoded element directly into the store

Parameters:

key - the key of the element

encoded - the encoded element

Returns:

true if the encoded element was installed

Throws:

IllegalArgumentException - if the supplied key is already present

getKeys

public List getKeys()

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

keySet

public Set<Object> keySet()

Get a set view of the keys in this store

Returns:

a set view of the keys in this store

remove

public Element remove(Object key)

Removes an item from the cache.

Specified by:

remove in interface Store

removeWithWriter

public Element removeWithWriter(Object key,
                                CacheWriterManager writerManager)

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

Specified by:

removeWithWriter in interface Store

removeAll

public void removeAll()

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

dispose

public void dispose()

Prepares for shutdown.

Specified by:

dispose in interface Store

clearFaultedBit

public void clearFaultedBit()

Marks all entries has flushed (i.e. not faulted)

getSize

public int getSize()

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

getStatus

public Status getStatus()

Returns the cache status.

Specified by:

getStatus in interface Store

containsKey

public boolean containsKey(Object key)

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

getInternalContext

public Object getInternalContext()

This should not be used, and will generally return null

Specified by:

getInternalContext in interface Store

Returns:

some internal context (probably null)

putIfAbsent

public Element putIfAbsent(Element element)
                    throws NullPointerException

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

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

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

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

fault

public boolean fault(Object key,
                     net.sf.ehcache.store.disk.DiskStorageFactory.Placeholder expect,
                     DiskStorageFactory.DiskMarker fault)

Atomically switch (CAS) the expect representation of this element for the fault representation.

A successful switch will return true, and free the replaced element/element-proxy. A failed switch will return false and free the element/element-proxy which was not installed.

Parameters:

key - key to which this element (proxy) is mapped

expect - element (proxy) expected

fault - element (proxy) to install

Returns:

true if fault was installed

evict

public boolean evict(Object key,
                     DiskStorageFactory.DiskSubstitute substitute)

Remove the matching mapping. The evict method does referential comparison of the unretrieved substitute against the argument value.

Parameters:

key - key to match against

substitute - optional value to match against

Returns:

true on a successful remove

evictElement

public Element evictElement(Object key,
                            DiskStorageFactory.DiskSubstitute substitute)

Remove the matching mapping. The evict method does referential comparison of the unretrieved substitute against the argument value.

Parameters:

key - key to match against

substitute - optional value to match against

Returns:

the evicted element on a successful remove

getRandomSample

public List<DiskStorageFactory.DiskSubstitute> getRandomSample(ElementSubstituteFilter factory,
                                                               int sampleSize,
                                                               Object keyHint)

Select a random sample of elements generated by the supplied factory.

Parameters:

factory - generator of the given type

sampleSize - minimum number of elements to return

keyHint - a key on which we are currently working

Returns:

list of sampled elements/element substitute