org.jboss.cache.loader.jdbm
Class JdbmCacheLoader

java.lang.Object
  org.jboss.cache.loader.AbstractCacheLoader
      org.jboss.cache.loader.jdbm.JdbmCacheLoader

All Implemented Interfaces:

CacheLoader

@ThreadSafe
public class JdbmCacheLoader
extends AbstractCacheLoader

A persistent CacheLoader based on the JDBM project. See http://jdbm.sourceforge.net/ . Does not support transaction isolation.

The configuration string format is:

environmentDirectoryName[#databaseName]

where databaseName, if omitted, defaults to the ClusterName property of the CacheImpl.

Data is sorted out like:

 / = N
 /node1 = N
 /node1/K/k1 = v1
 /node1/K/k2 = v2
 /node2 = N
 /node2/node3 = N
 /node2/node3/K/k1 = v1
 /node2/node3/K/k2 = v2
 /node2/node4 = N
 

N represents a node, K represents a key block. k and v represent key/value pairs.

The browse operations lock the entire tree; eventually the JDBM team plans to fix this.

Version:

$Id: JdbmCacheLoader.java 6120 2008-06-30 11:58:59Z manik.surtani@jboss.com $

Author:

Elias Ross

Field Summary

Fields inherited from class org.jboss.cache.loader.AbstractCacheLoader

buddyFqnTransformer, cache, regionManager, transactions

Constructor Summary

JdbmCacheLoader()

Method Summary

void	create() Lifecycle method, called when the cache loader is created.
void	dump() Dumps the tree to debug.
void	dump(Object key) Dumps the tree past the key to debug.
boolean	exists(Fqn name) Returns whether the given node exists.
Map	get(Fqn name) Returns a map containing all key-value pairs for the given FQN, or null if the node is not present.
Set<String>	getChildrenNames(Fqn name) Returns an unmodifiable set of relative children names, or returns null if the parent node is not found or if no children are found.
CacheLoaderConfig.IndividualCacheLoaderConfig	getConfig() Gets the configuration.
void	put(Fqn name, Map values) Stores a map of key-values for a given FQN, but does not delete existing key-value pairs (that is, it does not erase).
Object	put(Fqn name, Object key, Object value) Stores a single FQN-key-value record.
void	put(List<Modification> modifications) Applies the given modifications.
void	remove(Fqn name) Deletes the node for a given FQN and all its descendent nodes.
Object	remove(Fqn name, Object key) Deletes a single FQN-key-value record.
void	removeData(Fqn name) Clears the map for the given node, but does not remove the node.
void	setCache(CacheSPI c) Sets the CacheImpl owner of this cache loader.
void	setConfig(CacheLoaderConfig.IndividualCacheLoaderConfig base) Sets the configuration string for this cache loader.
void	start() Opens the environment and the database specified by the configuration string.
void	stop() Closes the databases and environment, and nulls references to them.
String	toString()

Methods inherited from class org.jboss.cache.loader.AbstractCacheLoader

commit, destroy, doMarshall, doUnmarshall, getMarshaller, getNodeDataList, loadEntireState, loadState, loadStateHelper, prepare, put, regionAwareMarshall, regionAwareUnmarshall, rollback, setRegionManager, storeEntireState, storeState, storeStateHelper

Methods inherited from class java.lang.Object

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

Constructor Detail

JdbmCacheLoader

public JdbmCacheLoader()

Method Detail

create

public void create()
            throws Exception

Description copied from interface: CacheLoader

Lifecycle method, called when the cache loader is created.

Specified by:

create in interface CacheLoader

Overrides:

create in class AbstractCacheLoader

Throws:

Exception

start

public void start()
           throws Exception

Opens the environment and the database specified by the configuration string. The environment and databases are created if necessary.

Specified by:

start in interface CacheLoader

Overrides:

start in class AbstractCacheLoader

Throws:

Exception

stop

public void stop()

Closes the databases and environment, and nulls references to them.

Specified by:

stop in interface CacheLoader

Overrides:

stop in class AbstractCacheLoader

setConfig

public void setConfig(CacheLoaderConfig.IndividualCacheLoaderConfig base)

Sets the configuration string for this cache loader.

Parameters:

base - May be an instance of the CacheLoaderConfig.IndividualCacheLoaderConfig base class, in which case the cache loader should use the PluggableConfigurationComponent.getProperties() method to find configuration information. Alternatively, may be a type-specific subclass of CacheLoaderConfig.IndividualCacheLoaderConfig, if there is one.

getConfig

public CacheLoaderConfig.IndividualCacheLoaderConfig getConfig()

Description copied from interface: CacheLoader

Gets the configuration.

Returns:

the configuration, represented by a CacheLoaderConfig.IndividualCacheLoaderConfig object.

setCache

public void setCache(CacheSPI c)

Sets the CacheImpl owner of this cache loader.

Specified by:

setCache in interface CacheLoader

Overrides:

setCache in class AbstractCacheLoader

Parameters:

c - The cache on which this loader works

getChildrenNames

public Set<String> getChildrenNames(Fqn name)
                             throws Exception

Returns an unmodifiable set of relative children names, or returns null if the parent node is not found or if no children are found. This is a fairly expensive operation, and is assumed to be performed by browser applications. Calling this method as part of a run-time transaction is not recommended.

Parameters:

name - The Fqn of the parent

Returns:

Set a set of children. Returns null if no children nodes are present, or the parent is not present

Throws:

Exception

get

public Map get(Fqn name)
        throws Exception

Returns a map containing all key-value pairs for the given FQN, or null if the node is not present. This operation is always non-transactional, even in a transactional environment.

Parameters:

name - the Fqn to search for.

Returns:

Map keys and values for the given node. Returns null if the node is not found. If the node is found but has no attributes, this method returns an empty Map.

Throws:

Exception

exists

public boolean exists(Fqn name)
               throws IOException

Returns whether the given node exists.

Returns:

true if node exists, false otherwise

Throws:

IOException

put

public Object put(Fqn name,
                  Object key,
                  Object value)
           throws Exception

Stores a single FQN-key-value record. Intended to be used in a non-transactional environment, but will use auto-commit in a transactional environment.

Throws:

Exception

put

public void put(Fqn name,
                Map values)
         throws Exception

Stores a map of key-values for a given FQN, but does not delete existing key-value pairs (that is, it does not erase). Intended to be used in a non-transactional environment, but will use auto-commit in a transactional environment.

Parameters:

name - The fully qualified name of the node

values - A Map of attributes. Can be null

Throws:

Exception

put

public void put(List<Modification> modifications)
         throws Exception

Applies the given modifications. Intended to be used in a non-transactional environment, but will use auto-commit in a transactional environment.

Specified by:

put in interface CacheLoader

Overrides:

put in class AbstractCacheLoader

Parameters:

modifications - A List of modifications

Throws:

Exception

remove

public void remove(Fqn name)
            throws Exception

Deletes the node for a given FQN and all its descendent nodes. Intended to be used in a non-transactional environment, but will use auto-commit in a transactional environment.

Parameters:

name - the Fqn of the node

Throws:

Exception

remove

public Object remove(Fqn name,
                     Object key)
              throws Exception

Deletes a single FQN-key-value record. Intended to be used in a non-transactional environment, but will use auto-commit in a transactional environment.

Throws:

Exception

removeData

public void removeData(Fqn name)
                throws Exception

Clears the map for the given node, but does not remove the node.

Parameters:

name - the Fqn of the node

Throws:

Exception

dump

public void dump()
          throws IOException

Dumps the tree to debug.

Throws:

IOException

dump

public void dump(Object key)
          throws IOException

Dumps the tree past the key to debug.

Throws:

IOException

toString

public String toString()

Overrides:

toString in class Object