org.jboss.cache.loader.bdbje
Class BdbjeCacheLoader

java.lang.Object
  extended by org.jboss.cache.loader.bdbje.BdbjeCacheLoader
All Implemented Interfaces:
CacheLoader, org.jboss.system.Service

public class BdbjeCacheLoader
extends java.lang.Object
implements CacheLoader

A persistent CacheLoader based on Berkeley DB Java Edition.

The configuration string format is:

environmentDirectoryName[#databaseName]

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

A je.properties file may optionally be placed in the JE environment directory and used to customize the default JE configuration.

Version:
$Id: BdbjeCacheLoader.java,v 1.11 2006/05/06 10:01:54 msurtani Exp $
Author:
Mark Hayes May 16, 2004, Bela Ban

Constructor Summary
BdbjeCacheLoader()
           
 
Method Summary
 void commit(java.lang.Object tx)
          Commits the given transaction, or throws IllegalArgumentException if the given key is not associated with an uncommited transaction.
 void create()
          Does nothing since start() does all the work.
 void destroy()
          Does nothing since stop() does all the work.
 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 getChildrenNames(Fqn name)
          Returns an unmodifiable set of relative children names (strings), or returns null if the parent node is not found or if no children are found.
 byte[] loadEntireState()
          Export the contents of the databases as a byte array.
 void prepare(java.lang.Object tx, java.util.List modifications, boolean onePhase)
          Begins a transaction and applies the given modifications.
 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 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)
          Commits the given transaction, or throws IllegalArgumentException if the given key is not associated with an uncommited transaction.
 void setCache(TreeCache c)
          Sets the TreeCache owner of this cache loader.
 void setConfig(java.util.Properties props)
          Sets the configuration string for this cache loader.
 void start()
          Opens the JE environment and the database specified by the configuration string.
 void stop()
          Closes the JE databases and environment, and nulls references to them.
 void storeEntireState(byte[] state)
          Replace the contents of the databases with the given exported data.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

BdbjeCacheLoader

public BdbjeCacheLoader()
Method Detail

create

public void create()
            throws java.lang.Exception
Does nothing since start() does all the work.

Specified by:
create in interface org.jboss.system.Service
Throws:
java.lang.Exception

destroy

public void destroy()
Does nothing since stop() does all the work.

Specified by:
destroy in interface org.jboss.system.Service

start

public void start()
           throws java.lang.Exception
Opens the JE environment and the database specified by the configuration string. The environment and databases are created if necessary.

Specified by:
start in interface org.jboss.system.Service
Throws:
java.lang.Exception

stop

public void stop()
Closes the JE databases and environment, and nulls references to them. The environment and databases are not removed from the file system. Exceptions during close are ignored.

Specified by:
stop in interface org.jboss.system.Service

setConfig

public void setConfig(java.util.Properties props)
Sets the configuration string for this cache loader.

Specified by:
setConfig in interface CacheLoader
Parameters:
props - a collection of configuration properties

setCache

public void setCache(TreeCache c)
Sets the TreeCache owner of this cache loader.

Specified by:
setCache in interface CacheLoader
Parameters:
c - The cache on which this loader works

getChildrenNames

public java.util.Set getChildrenNames(Fqn name)
                               throws java.lang.Exception
Returns an unmodifiable set of relative children names (strings), 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.

Specified by:
getChildrenNames in interface CacheLoader
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.

Specified by:
get in interface CacheLoader
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.lang.Exception
Returns whether the given node exists.

Specified by:
exists in interface CacheLoader
Returns:
true if node exists, false otherwise
Throws:
java.lang.Exception

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.

Specified by:
put in interface CacheLoader
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.

Specified by:
put in interface CacheLoader
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 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
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.

Specified by:
remove in interface CacheLoader
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.

Specified by:
remove in interface CacheLoader
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.

Specified by:
removeData in interface CacheLoader
Throws:
java.lang.Exception

prepare

public void prepare(java.lang.Object tx,
                    java.util.List modifications,
                    boolean onePhase)
             throws java.lang.Exception
Begins a transaction and applies the given modifications.

If onePhase is true, commits the transaction; otherwise, associates the txn value with the transaction and expects commit() or rollback() to be called later with the same tx value. Performs retries if necessary to resolve deadlocks.

Specified by:
prepare in interface CacheLoader
Parameters:
tx - The transaction, just used as a hashmap key
modifications - List, a list of all modifications within 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 the given transaction, or throws IllegalArgumentException if the given key is not associated with an uncommited transaction.

Specified by:
commit in interface CacheLoader
Parameters:
tx - transaction to commit
Throws:
java.lang.Exception

rollback

public void rollback(java.lang.Object tx)
Commits the given transaction, or throws IllegalArgumentException if the given key is not associated with an uncommited transaction.

Specified by:
rollback in interface CacheLoader
Parameters:
tx - transaction to roll back

loadEntireState

public byte[] loadEntireState()
                       throws java.lang.Exception
Export the contents of the databases as a byte array. If the databases are empty a zero-lenth array is returned. The export format is two consecutive DbDumps.

Specified by:
loadEntireState in interface CacheLoader
Throws:
java.lang.Exception

storeEntireState

public void storeEntireState(byte[] state)
                      throws java.lang.Exception
Replace the contents of the databases with the given exported data. If state is null or zero-length, the databases will be cleared. The export format is two consecutive DbDumps.

Specified by:
storeEntireState in interface CacheLoader
Throws:
java.lang.Exception


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