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.

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

Version:

$Id: JdbmCacheLoader.java,v 1.28 2007/06/19 17:46:50 msurtani Exp $

Author:

Elias Ross

Field Summary

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

cache, regionManager

Constructor Summary

JdbmCacheLoader()

Method Summary

void	commit(java.lang.Object tx) Commits a transaction.
void	create() Lifecycle method, called when the cache loader is created.
void	destroy() Lifecycle method, called when the cache loader is destroyed.
void	dump() Dumps the tree to debug.
void	dump(java.lang.Object key) Dumps the tree past the key to debug.
boolean	exists(Fqn name) Returns whether the given node exists.
java.util.Map	get(Fqn name) Returns a map containing all key-value pairs for the given FQN, or null if the node is not present.
java.util.Set<java.lang.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	prepare(java.lang.Object tx, java.util.List<Modification> modifications, boolean onePhase) Applies and commits the given modifications in one transaction.
void	put(Fqn name, java.util.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).
java.lang.Object	put(Fqn name, java.lang.Object key, java.lang.Object value) Stores a single FQN-key-value record.
void	put(java.util.List<Modification> modifications) Applies the given modifications.
void	remove(Fqn name) Deletes the node for a given FQN and all its descendent nodes.
java.lang.Object	remove(Fqn name, java.lang.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	rollback(java.lang.Object tx) Removes transaction in progress.
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.
java.lang.String	toString()

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

getMarshaller, getNodeDataList, loadEntireState, loadState, loadStateHelper, put, setRegionManager, storeEntireState, storeState

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 java.lang.Exception

Description copied from interface: CacheLoader

Lifecycle method, called when the cache loader is created.

Throws:

java.lang.Exception

destroy

public void destroy()

Description copied from interface: CacheLoader

Lifecycle method, called when the cache loader is destroyed.

start

public void start()
           throws java.lang.Exception

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

Throws:

java.lang.Exception

stop

public void stop()

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

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 CacheLoaderConfig.IndividualCacheLoaderConfig.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 java.util.Set<java.lang.String> getChildrenNames(Fqn name)
                                                 throws java.lang.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:

java.lang.Exception

get

public java.util.Map get(Fqn name)
                  throws java.lang.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:

java.lang.Exception

exists

public boolean exists(Fqn name)
               throws java.io.IOException

Returns whether the given node exists.

Returns:

true if node exists, false otherwise

Throws:

java.io.IOException

put

public java.lang.Object put(Fqn name,
                            java.lang.Object key,
                            java.lang.Object value)
                     throws java.lang.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:

java.lang.Exception

put

public void put(Fqn name,
                java.util.Map values)
         throws java.lang.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:

java.lang.Exception

put

public void put(java.util.List<Modification> modifications)
         throws java.lang.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:

java.lang.Exception

remove

public void remove(Fqn name)
            throws java.lang.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:

java.lang.Exception

remove

public java.lang.Object remove(Fqn name,
                               java.lang.Object key)
                        throws java.lang.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:

java.lang.Exception

removeData

public void removeData(Fqn name)
                throws java.lang.Exception

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

Parameters:

name - the Fqn of the node

Throws:

java.lang.Exception

prepare

public void prepare(java.lang.Object tx,
                    java.util.List<Modification> modifications,
                    boolean onePhase)
             throws java.lang.Exception

Applies and commits the given modifications in one transaction.

Parameters:

tx - The transaction, indended to be used by implementations as an identifier of the transaction (and not necessarily a JTA Transaction object)

modifications - A List containing Modifications, for the given transaction

onePhase - Persist immediately and (for example) commit the local JDBC transaction as well. When true, we won't get a CacheLoader.commit(Object) or CacheLoader.rollback(Object) method call later

Throws:

java.lang.Exception

commit

public void commit(java.lang.Object tx)
            throws java.lang.Exception

Commits a transaction.

Parameters:

tx - transaction to commit

Throws:

java.lang.Exception

rollback

public void rollback(java.lang.Object tx)

Removes transaction in progress.

Parameters:

tx - transaction to roll back

dump

public void dump()
          throws java.io.IOException

Dumps the tree to debug.

Throws:

java.io.IOException

dump

public void dump(java.lang.Object key)
          throws java.io.IOException

Dumps the tree past the key to debug.

Throws:

java.io.IOException

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object