org.jboss.cache.loader
Class JDBCCacheLoader

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

All Implemented Interfaces:

CacheLoader (src) , Service (src)

public class JDBCCacheLoader

extends java.lang.Object

implements CacheLoader (src)

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.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

JDBCCacheLoader

public JDBCCacheLoader()

setConfig

public void setConfig(java.util.Properties props)

Description copied from interface: CacheLoader (src)

Sets the configuration. Will be called before Service.create() and Service.start()

Specified by:

setConfig in interface CacheLoader (src)

Parameters:

props - A list of properties, defined in the XML file

setCache

public void setCache(TreeCache (src)  c)

Description copied from interface: CacheLoader (src)

This method allows the CacheLoader to set the TreeCache, therefore allowing the CacheLoader to invoke methods of the TreeCache. It can also use the TreeCache to fetch configuration information. Alternatively, the CacheLoader could maintain its own configuration
This method will be called directly after the CacheLoader instance has been created

Specified by:

setCache in interface CacheLoader (src)

Parameters:

c - The cache on which this loader works

getChildrenNames

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

Fetches child node names (not pathes).

Specified by:

getChildrenNames in interface CacheLoader (src)

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.lang.Object get(Fqn (src)  name,
                            java.lang.Object key)
                     throws java.lang.Exception

Loads an attribute from the database.

Specified by:

get in interface CacheLoader (src)

Parameters:

name - node's fqn

key - attribute's key

Returns:

attribute's value. Null is returned if

• there is no value for the attribute key in the node
• there is a row in the table for the fqn but the node column contains null
• there is no row in table for the fqn (should this result in an exception?)

Throws:

java.lang.Exception

get

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

Returns a map representing a node.

Specified by:

get in interface CacheLoader (src)

Parameters:

name - node's fqn

Returns:

node

Throws:

java.lang.Exception

exists

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

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

Specified by:

exists in interface CacheLoader (src)

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 (src)  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 (src)

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 (src)  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 (src)

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 (src)

Inserts all modifications to the backend store. Overwrite whatever is already in the datastore.

Specified by:

put in interface CacheLoader (src)

Parameters:

modifications - A List of modifications

Throws:

java.lang.Exception

remove

public java.lang.Object remove(Fqn (src)  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 (src)

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 (src)  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 (src)

Parameters:

name - node's fqn

Throws:

java.lang.Exception

removeData

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

Nullifies the node.

Specified by:

removeData in interface CacheLoader (src)

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 (src)

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 (src)

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 (src)

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 (src)

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 (src)

Parameters:

state -

Throws:

java.lang.Exception

create

public void create()
            throws java.lang.Exception

Description copied from interface: Service (src)

create the service, do expensive operations etc

Specified by:

create in interface Service (src)

Throws:

java.lang.Exception

start

public void start()
           throws java.lang.Exception

Description copied from interface: Service (src)

start the service, create is already called

Specified by:

start in interface Service (src)

Throws:

java.lang.Exception

stop

public void stop()

Description copied from interface: Service (src)

stop the service

Specified by:

stop in interface Service (src)

destroy

public void destroy()

Description copied from interface: Service (src)

destroy the service, tear down

Specified by:

destroy in interface Service (src)