org.jboss.cache.loader
Class JDBCCacheLoader

java.lang.Object
  org.jboss.cache.loader.JDBCCacheLoader

All Implemented Interfaces:

CacheLoader, org.jboss.system.Service

Direct Known Subclasses:

JDBCExtendedCacheLoader

public class JDBCCacheLoader
extends java.lang.Object
implements CacheLoader

JDBC CacheLoader implementation.

This implementation uses one table. The table consists of three columns:

• text column for fqn (which is also a primary key)
• blob column for attributes (can contain null)
• text column for parent fqn (can contain null)

The configuration options are:

Table configuration

• cache.jdbc.table.name - the table name (default is jbosscache)
• cache.jdbc.table.create - should be true or false, indicates whether to create the table at start phase
• cache.jdbc.table.drop - should be true or false, indicates whether to drop the table at stop phase
• cache.jdbc.table.primarykey - the name for the table primary key (default is jbosscache_pk)
• cache.jdbc.fqn.column - the name for the fqn column (default is fqn)
• cache.jdbc.fqn.type - the type for the fqn column (default is varchar(255))
• cache.jdbc.node.column - the name for the node's contents column (default is node)
• cache.jdbc.node.type - the type for the node's contents column (default is blob)
• cache.jdbc.parent.column - the name for the parent fqn column (default is parent)

DataSource configuration

• cache.jdbc.datasource - the JNDI name of the datasource

JDBC driver configuration (used when DataSource is not configured)

• cache.jdbc.driver - fully qualified JDBC driver name
• cache.jdbc.url - URL to connect to the database
• cache.jdbc.user - the username to use to connect to the database
• cache.jdbc.password - the password to use to connect to the database

Version:

$Revision: 1.11 $

Author:

Alexey Loubyansky, Hany Mesha

Constructor Summary

JDBCCacheLoader()

Method Summary

void	commit(java.lang.Object tx) Commits a transaction.
void	create()
void	destroy()
boolean	exists(Fqn name) Checks that there is a row for the fqn in the database.
java.util.Map	get(Fqn name) Returns a map representing a node.
java.util.Set	getChildrenNames(Fqn fqn) Fetches child node names (not pathes).
byte[]	loadEntireState() Loads the entire state from the filesystem and returns it as a byte buffer.
protected void	loadState(Fqn fqn, java.io.ObjectOutputStream out) Do a preorder traversal: visit the node first, then the node's children
void	prepare(java.lang.Object tx, java.util.List modifications, boolean one_phase) First phase in transaction commit process.
void	put(Fqn name, java.util.Map attributes) Adds attributes from the passed in map to the existing node.
java.lang.Object	put(Fqn name, java.lang.Object key, java.lang.Object value) Adds/overrides a value in a node for a key.
void	put(java.util.List modifications) Applies all modifications to the backend store.
void	remove(Fqn name) Removes a node and all its children.
java.lang.Object	remove(Fqn name, java.lang.Object key) Removes attribute's value for a key.
void	removeData(Fqn name) Nullifies the node.
void	rollback(java.lang.Object tx) Rolls back a transaction.
void	setCache(TreeCache c) Sets the TreeCache that is maintaining this CacheLoader.
void	setConfig(java.util.Properties props) Sets the configuration.
void	start()
void	stop()
void	storeEntireState(byte[] state) Store the state given as a byte buffer to the database.

Methods inherited from class java.lang.Object

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

Constructor Detail

JDBCCacheLoader

public JDBCCacheLoader()

Method Detail

setConfig

public void setConfig(java.util.Properties props)

Description copied from interface: CacheLoader

Sets the configuration. This is called before Service.create() and Service.start().

Specified by:

setConfig in interface CacheLoader

Parameters:

props - a collection of configuration properties

setCache

public void setCache(TreeCache c)

Description copied from interface: CacheLoader

Sets the TreeCache that is maintaining this CacheLoader. This method allows this CacheLoader to invoke methods on TreeCache, including fetching additional configuration information. This method is called be called after the CacheLoader instance has been constructed.

Specified by:

setCache in interface CacheLoader

Parameters:

c - The cache on which this loader works

getChildrenNames

public java.util.Set getChildrenNames(Fqn fqn)
                               throws java.lang.Exception

Fetches child node names (not pathes).

Specified by:

getChildrenNames in interface CacheLoader

Parameters:

fqn - parent fqn

Returns:

a set of child node names or null if there are not children found for the fqn

Throws:

java.lang.Exception

get

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

Returns a map representing a node.

Specified by:

get in interface CacheLoader

Parameters:

name - node's fqn

Returns:

node

Throws:

java.lang.Exception

exists

public boolean exists(Fqn name)
               throws java.lang.Exception

Checks that there is a row for the fqn in the database.

Specified by:

exists in interface CacheLoader

Parameters:

name - node's fqn

Returns:

true if there is a row in the database for the given fqn even if the node column is null.

Throws:

java.lang.Exception

put

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

Adds/overrides a value in a node for a key. If the node does not exist yet, the node will be created. If parent nodes do not exist for the node, empty parent nodes will be created.

Specified by:

put in interface CacheLoader

Parameters:

name - node's fqn

key - attribute's key

value - attribute's value

Returns:

old value associated with the attribute's key or null if there was no value previously associated with the attribute's key

Throws:

java.lang.Exception

put

public void put(Fqn name,
                java.util.Map attributes)
         throws java.lang.Exception

Adds attributes from the passed in map to the existing node. If there is no node for the fqn, a new node will be created.

Specified by:

put in interface CacheLoader

Parameters:

name - node's fqn

attributes - attributes

Throws:

java.lang.Exception

put

public void put(java.util.List modifications)
         throws java.lang.Exception

Description copied from interface: CacheLoader

Applies all modifications to the backend store. Changes may be applied in a single operation.

Specified by:

put in interface CacheLoader

Parameters:

modifications - A List of modifications

Throws:

java.lang.Exception

remove

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

Removes attribute's value for a key. If after removal the node contains no attributes, the node is nullified.

Specified by:

remove in interface CacheLoader

Parameters:

name - node's name

key - attribute's key

Returns:

removed value or null if there was no value for the passed in key

Throws:

java.lang.Exception

remove

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

Removes a node and all its children. Uses the same connection for all the db work.

Specified by:

remove in interface CacheLoader

Parameters:

name - node's fqn

Throws:

java.lang.Exception

removeData

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

Nullifies the node.

Specified by:

removeData in interface CacheLoader

Parameters:

name - node's fqn

Throws:

java.lang.Exception

prepare

public void prepare(java.lang.Object tx,
                    java.util.List modifications,
                    boolean one_phase)
             throws java.lang.Exception

First phase in transaction commit process. The changes are committed if only one phase if requested. All the modifications are committed using the same connection.

Specified by:

prepare in interface CacheLoader

Parameters:

tx - something representing transaction

modifications - a list of modifications

one_phase - indicates whether it's one or two phase commit transaction

Throws:

java.lang.Exception

commit

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

Commits a transaction.

Specified by:

commit in interface CacheLoader

Parameters:

tx - the tx to commit

Throws:

java.lang.Exception

rollback

public void rollback(java.lang.Object tx)

Rolls back a transaction.

Specified by:

rollback in interface CacheLoader

Parameters:

tx - the tx to rollback

loadEntireState

public byte[] loadEntireState()
                       throws java.lang.Exception

Loads the entire state from the filesystem and returns it as a byte buffer. The format of the byte buffer must be a list of NodeData elements

Specified by:

loadEntireState in interface CacheLoader

Returns:

Throws:

java.lang.Exception

storeEntireState

public void storeEntireState(byte[] state)
                      throws java.lang.Exception

Store the state given as a byte buffer to the database. The byte buffer contains a list of zero or more NodeData elements

Specified by:

storeEntireState in interface CacheLoader

Parameters:

state -

Throws:

java.lang.Exception

create

public void create()
            throws java.lang.Exception

Specified by:

create in interface org.jboss.system.Service

Throws:

java.lang.Exception

start

public void start()
           throws java.lang.Exception

Specified by:

start in interface org.jboss.system.Service

Throws:

java.lang.Exception

stop

public void stop()

Specified by:

stop in interface org.jboss.system.Service

destroy

public void destroy()

Specified by:

destroy in interface org.jboss.system.Service

loadState

protected void loadState(Fqn fqn,
                         java.io.ObjectOutputStream out)
                  throws java.lang.Exception

Do a preorder traversal: visit the node first, then the node's children

Parameters:

fqn - Start node

out -

Throws:

java.lang.Exception