com.opensymphony.oscache.plugins.diskpersistence
Class AbstractDiskPersistenceListener

java.lang.Object
  com.opensymphony.oscache.plugins.diskpersistence.AbstractDiskPersistenceListener

All Implemented Interfaces:

PersistenceListener, java.io.Serializable

Direct Known Subclasses:

DiskPersistenceListener, HashDiskPersistenceListener

public abstract class AbstractDiskPersistenceListener
extends java.lang.Object
implements PersistenceListener, java.io.Serializable

Persist the cache data to disk. The code in this class is totally not thread safe it is the resonsibility of the cache using this persistence listener to handle the concurrency.

Author:

Francois Beauregard, Alain Bergevin, Chris Miller, Andres March

See Also:

Serialized Form

Field Summary

protected static java.lang.String	APPLICATION_CACHE_SUBPATH Sub path name for application cache
protected static java.lang.String	CACHE_EXTENSION File extension for disk cache file
static java.lang.String	CACHE_PATH_KEY
protected static java.lang.String	CONTEXT_TMPDIR Property to get the temporary working directory of the servlet container.
protected static java.lang.String	GROUP_DIRECTORY The directory that cache groups are stored under
protected static java.lang.String	SESSION_CACHE_SUBPATH Sub path name for session cache

Constructor Summary

AbstractDiskPersistenceListener()

Method Summary

protected java.lang.String	adjustFileCachePath(java.lang.String cachePathStr) Allows to translate to the temp dir of the servlet container if cachePathStr is javax.servlet.context.tempdir.
void	clear() Clears the whole cache directory, starting from the root
PersistenceListener	configure(Config config) Initialises this DiskPersistenceListener using the supplied configuration.
protected java.io.File	getCacheFile(java.lang.String key) Build fully qualified cache file for the specified cache entry key.
protected abstract char[]	getCacheFileName(java.lang.String key) Build cache file name for the specified cache entry key.
java.io.File	getCachePath() Get the physical cache path on disk.
java.io.File	getContextTmpDir() Get the servlet context tmp directory.
java.lang.String	getRoot() Get the root directory for persisting the cache on disk.
protected void	initFileCaching(java.lang.String cachePathStr) Set caching to file on or off.
boolean	isGroupStored(java.lang.String group) Verify if a group exists in the cache
boolean	isStored(java.lang.String key) Verify if an object is currently stored in the cache
protected void	remove(java.io.File file)
void	remove(java.lang.String key) Delete a single cache entry.
void	removeGroup(java.lang.String groupName) Deletes an entire group from the cache.
java.lang.Object	retrieve(java.lang.String key) Retrieve an object from the disk
java.util.Set	retrieveGroup(java.lang.String groupName) Retrieves a group from the cache, or null if the group file could not be found.
protected void	store(java.io.File file, java.lang.Object obj) Stores an object using the supplied file object
void	store(java.lang.String key, java.lang.Object obj) Stores an object in cache
void	storeGroup(java.lang.String groupName, java.util.Set group) Stores a group in the persistent cache.

Methods inherited from class java.lang.Object

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

Field Detail

CACHE_PATH_KEY

public static final java.lang.String CACHE_PATH_KEY

See Also:

Constant Field Values

CACHE_EXTENSION

protected static final java.lang.String CACHE_EXTENSION

File extension for disk cache file

See Also:

Constant Field Values

GROUP_DIRECTORY

protected static final java.lang.String GROUP_DIRECTORY

The directory that cache groups are stored under

See Also:

Constant Field Values

APPLICATION_CACHE_SUBPATH

protected static final java.lang.String APPLICATION_CACHE_SUBPATH

Sub path name for application cache

See Also:

Constant Field Values

SESSION_CACHE_SUBPATH

protected static final java.lang.String SESSION_CACHE_SUBPATH

Sub path name for session cache

See Also:

Constant Field Values

CONTEXT_TMPDIR

protected static final java.lang.String CONTEXT_TMPDIR

Property to get the temporary working directory of the servlet container.

See Also:

Constant Field Values

Constructor Detail

AbstractDiskPersistenceListener

public AbstractDiskPersistenceListener()

Method Detail

getCachePath

public java.io.File getCachePath()

Get the physical cache path on disk.

Returns:

A file representing the physical cache location.

getRoot

public java.lang.String getRoot()

Get the root directory for persisting the cache on disk. This path includes scope and sessionId, if any.

Returns:

A String representing the root directory.

getContextTmpDir

public java.io.File getContextTmpDir()

Get the servlet context tmp directory.

Returns:

A file representing the servlet context tmp directory.

isGroupStored

public boolean isGroupStored(java.lang.String group)
                      throws CachePersistenceException

Verify if a group exists in the cache

Specified by:

isGroupStored in interface PersistenceListener

Parameters:

group - The group name to check

Returns:

True if it exists

Throws:

CachePersistenceException

isStored

public boolean isStored(java.lang.String key)
                 throws CachePersistenceException

Verify if an object is currently stored in the cache

Specified by:

isStored in interface PersistenceListener

Parameters:

key - The object key

Returns:

True if it exists

Throws:

CachePersistenceException

clear

public void clear()
           throws CachePersistenceException

Clears the whole cache directory, starting from the root

Specified by:

clear in interface PersistenceListener

Throws:

CachePersistenceException

configure

public PersistenceListener configure(Config config)

Initialises this DiskPersistenceListener using the supplied configuration.

Specified by:

configure in interface PersistenceListener

Parameters:

config - The OSCache configuration

remove

public void remove(java.lang.String key)
            throws CachePersistenceException

Delete a single cache entry.

Specified by:

remove in interface PersistenceListener

Parameters:

key - The object key to delete

Throws:

CachePersistenceException

removeGroup

public void removeGroup(java.lang.String groupName)
                 throws CachePersistenceException

Deletes an entire group from the cache.

Specified by:

removeGroup in interface PersistenceListener

Parameters:

groupName - The name of the group to delete

Throws:

CachePersistenceException

retrieve

public java.lang.Object retrieve(java.lang.String key)
                          throws CachePersistenceException

Retrieve an object from the disk

Specified by:

retrieve in interface PersistenceListener

Parameters:

key - The object key

Returns:

The retrieved object

Throws:

CachePersistenceException

retrieveGroup

public java.util.Set retrieveGroup(java.lang.String groupName)
                            throws CachePersistenceException

Retrieves a group from the cache, or null if the group file could not be found.

Specified by:

retrieveGroup in interface PersistenceListener

Parameters:

groupName - The name of the group to retrieve.

Returns:

A Set containing keys of all of the cache entries that belong to this group.

Throws:

CachePersistenceException

store

public void store(java.lang.String key,
                  java.lang.Object obj)
           throws CachePersistenceException

Stores an object in cache

Specified by:

store in interface PersistenceListener

Parameters:

key - The object's key

obj - The object to store

Throws:

CachePersistenceException

storeGroup

public void storeGroup(java.lang.String groupName,
                       java.util.Set group)
                throws CachePersistenceException

Stores a group in the persistent cache. This will overwrite any existing group with the same name

Specified by:

storeGroup in interface PersistenceListener

Parameters:

groupName - The name of the group to persist.

group - A set containing the keys of all the CacheEntry objects that belong to this group.

Throws:

CachePersistenceException

adjustFileCachePath

protected java.lang.String adjustFileCachePath(java.lang.String cachePathStr)

Allows to translate to the temp dir of the servlet container if cachePathStr is javax.servlet.context.tempdir.

Parameters:

cachePathStr - Cache path read from the properties file.

Returns:

Adjusted cache path

initFileCaching

protected void initFileCaching(java.lang.String cachePathStr)

Set caching to file on or off. If the cache.path property exists, we assume file caching is turned on. By the same token, to turn off file caching just remove this property.

remove

protected void remove(java.io.File file)
               throws CachePersistenceException

Throws:

CachePersistenceException

store

protected void store(java.io.File file,
                     java.lang.Object obj)
              throws CachePersistenceException

Stores an object using the supplied file object

Parameters:

file - The file to use for storing the object

obj - the object to store

Throws:

CachePersistenceException

getCacheFile

protected java.io.File getCacheFile(java.lang.String key)

Build fully qualified cache file for the specified cache entry key.

Parameters:

key - Cache Entry Key.

Returns:

File reference.

getCacheFileName

protected abstract char[] getCacheFileName(java.lang.String key)

Build cache file name for the specified cache entry key.

Parameters:

key - Cache Entry Key.

Returns:

char[] file name.