net.sf.ehcache.store.compound.factories
Class DiskOverflowStorageFactory

java.lang.Object
  net.sf.ehcache.store.compound.factories.DiskOverflowStorageFactory

All Implemented Interfaces:

ElementSubstituteFactory<ElementSubstitute>

public class DiskOverflowStorageFactory
extends Object

A factory that stores elements on disk in their serialized form.

Author:

Chris Dennis

Field Summary

protected static String	AUTO_DISK_PATH_DIRECTORY_PREFIX Path stub used to create unique ehcache directories.
protected CompoundStore	store The store bound to this factory.

Constructor Summary

DiskOverflowStorageFactory(Ehcache cache, String diskPath)
Constructs an overflow factory for the given cache and disk path.

Method Summary

void	bind(CompoundStore store) Bind a store instance to this factory.
boolean	bufferFull() Return true if the disk write queue is full.
ElementSubstitute	create(Object key, Element element) Encodes an Element as a marker to on-disk location.
boolean	created(Object object) Returns true if this factory created the given object.
protected net.sf.ehcache.store.compound.factories.DiskStorageFactory.DiskMarker	createMarker(long position, int size, Element element) Create a disk marker representing the given element, and area on disk.
protected void	delete() Deletes the data file for this factory.
void	expireElements() Remove elements created by this factory if they have expired.
protected void	free(net.sf.ehcache.store.compound.factories.DiskStorageFactory.DiskMarker marker) Free the given marker to be used by a subsequent write.
void	free(Lock lock, ElementSubstitute substitute) Free any manually managed resources used by this ElementSubstitute.
File	getDataFile() Return a reference to the data file backing this factory.
long	getOnDiskSizeInBytes() Return this size in bytes of this factory
int	getSize() Return the count of elements created by this factory.
protected void	markUsed(net.sf.ehcache.store.compound.factories.DiskStorageFactory.DiskMarker marker) Mark this on-disk marker as used (hooks into the file space allocation structure).
void	primary(CapacityLimitedInMemoryFactory memory) Sets the primary factory that this factory should fault to, when elements are retrieved.
protected Element	read(net.sf.ehcache.store.compound.factories.DiskStorageFactory.DiskMarker marker) Read the data at the given marker, and return the associated deserialized Element.
Element	retrieve(Object key, ElementSubstitute proxy) Decode an ElementProxy from an on disk marker (or a pending placeholder).
protected <U> Future<U>	schedule(Callable<U> call) Schedule to given task on the disk writer executor service.
void	setCapacity(int newCapacity) Set the maximum on-disk capacity for this factory.
protected void	shrinkDataFile() Shrink this store's data file down to a minimal size for its contents.
protected void	shutdown() Shuts down this disk factory.
void	unbind(CompoundStore localStore) Unbinds a store instance from this factory
protected net.sf.ehcache.store.compound.factories.DiskStorageFactory.DiskMarker	write(Element element) Write the given element to disk, and return the associated marker.

Methods inherited from class java.lang.Object

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

Field Detail

AUTO_DISK_PATH_DIRECTORY_PREFIX

protected static final String AUTO_DISK_PATH_DIRECTORY_PREFIX

Path stub used to create unique ehcache directories.

See Also:

Constant Field Values

store

protected volatile CompoundStore store

The store bound to this factory.

Constructor Detail

DiskOverflowStorageFactory

public DiskOverflowStorageFactory(Ehcache cache,
                                  String diskPath)

Constructs an overflow factory for the given cache and disk path.

Parameters:

cache - cache that fronts this factory

diskPath - path to store data in

Method Detail

primary

public void primary(CapacityLimitedInMemoryFactory memory)

Sets the primary factory that this factory should fault to, when elements are retrieved.

create

public ElementSubstitute create(Object key,
                                Element element)
                         throws IllegalArgumentException

Encodes an Element as a marker to on-disk location.

Immediately substitutes a placeholder for the original element while the Element itself is asynchronously written to disk using the executor service.

Parameters:

key - key to which this element is mapped

element - Element to encode

Returns:

The substitute element

Throws:

IllegalArgumentException

retrieve

public Element retrieve(Object key,
                        ElementSubstitute proxy)

Decode an ElementProxy from an on disk marker (or a pending placeholder).

This implementation makes no attempt to fault in the decoded Element in place of the proxy.

Parameters:

key - key to which this element is mapped

proxy - ElementSubstitute to decode

Returns:

a decoded Element

free

public void free(Lock lock,
                 ElementSubstitute substitute)

Free any manually managed resources used by this ElementSubstitute.

Specified by:

free in interface ElementSubstituteFactory<ElementSubstitute>

substitute - ElementSubstitute being free'd.

unbind

public void unbind(CompoundStore localStore)

Unbinds a store instance from this factory

Parameters:

localStore - store to unbind

getSize

public int getSize()

Return the count of elements created by this factory.

setCapacity

public void setCapacity(int newCapacity)

Set the maximum on-disk capacity for this factory.

created

public boolean created(Object object)

Returns true if this factory created the given object.

Parameters:

object - object to check

Returns:

true if object created by this factory

getOnDiskSizeInBytes

public long getOnDiskSizeInBytes()

Return this size in bytes of this factory

bind

public void bind(CompoundStore store)

Bind a store instance to this factory.

Parameters:

store - store to bind

markUsed

protected void markUsed(net.sf.ehcache.store.compound.factories.DiskStorageFactory.DiskMarker marker)

Mark this on-disk marker as used (hooks into the file space allocation structure).

shrinkDataFile

protected void shrinkDataFile()

Shrink this store's data file down to a minimal size for its contents.

shutdown

protected void shutdown()
                 throws IOException

Shuts down this disk factory.

This shuts down the executor and then waits for its termination, before closing the data file.

Throws:

IOException

delete

protected void delete()

Deletes the data file for this factory.

schedule

protected <U> Future<U> schedule(Callable<U> call)

Schedule to given task on the disk writer executor service.

Type Parameters:

U - return type of the callable

Parameters:

call - callable to call

Returns:

Future representing the return of this call

read

protected Element read(net.sf.ehcache.store.compound.factories.DiskStorageFactory.DiskMarker marker)
                throws IOException,
                       ClassNotFoundException

Read the data at the given marker, and return the associated deserialized Element.

Parameters:

marker - marker to read

Returns:

deserialized Element

Throws:

IOException - on read error

ClassNotFoundException - on deserialization error

write

protected net.sf.ehcache.store.compound.factories.DiskStorageFactory.DiskMarker write(Element element)
                                                                               throws IOException

Write the given element to disk, and return the associated marker.

Parameters:

element - to write

Returns:

marker representing the element

Throws:

IOException - on write error

createMarker

protected net.sf.ehcache.store.compound.factories.DiskStorageFactory.DiskMarker createMarker(long position,
                                                                                             int size,
                                                                                             Element element)

Create a disk marker representing the given element, and area on disk.

This method can be overridden by subclasses to use different marker types.

Parameters:

position - starting disk offset

size - size of in disk area

element - element to be written to area

Returns:

marker representing the element.

free

protected void free(net.sf.ehcache.store.compound.factories.DiskStorageFactory.DiskMarker marker)

Free the given marker to be used by a subsequent write.

Parameters:

marker - marker to be free'd

bufferFull

public boolean bufferFull()

Return true if the disk write queue is full.

getDataFile

public File getDataFile()

Return a reference to the data file backing this factory.

expireElements

public void expireElements()

Remove elements created by this factory if they have expired.