org.jboss.cache.loader
Class ClusteredCacheLoader

java.lang.Object
  extended by org.jboss.cache.loader.AbstractCacheLoader
      extended by org.jboss.cache.loader.ClusteredCacheLoader
All Implemented Interfaces:
Lifecycle, CacheLoader

@ThreadSafe
public class ClusteredCacheLoader
extends AbstractCacheLoader

A cache loader that consults other members in the cluster for values. Does not propagate update methods since replication should take care of this. A timeout property is required, a long that specifies in milliseconds how long to wait for results before returning a null.

Author:
Manik Surtani (manik AT jboss DOT org)

Nested Class Summary
static class ClusteredCacheLoader.ResponseValidityFilter
           
 
Field Summary
 
Fields inherited from class org.jboss.cache.loader.AbstractCacheLoader
buddyFqnTransformer, cache, regionManager, transactions
 
Constructor Summary
ClusteredCacheLoader()
           
 
Method Summary
 void commit(Object tx)
          Does nothing.
 boolean exists(Fqn name)
          Returns true if the CacheLoader has a node with a Fqn.
 Map get(Fqn name)
          Returns all keys and values from the persistent store, given a Fqn
protected  Map get0(Fqn name)
           
 Set getChildrenNames(Fqn fqn)
          Returns a set of children node names.
 CacheLoaderConfig.IndividualCacheLoaderConfig getConfig()
          Gets the configuration.
protected  boolean isCacheReady()
          A test to check whether the cache is in its started state.
 void loadEntireState(ObjectOutputStream os)
          Fetches the entire state for this cache from secondary storage (disk, database) and writes it to a provided ObjectOutputStream.
 void loadState(Fqn subtree, ObjectOutputStream os)
          Fetches a portion of the state for this cache from secondary storage (disk, database) and writes it to a provided ObjectOutputStream.
 void prepare(Object tx, List modifications, boolean one_phase)
          Does nothing.
 void put(Fqn name, Map attributes)
          Does nothing; replication handles put.
 Object put(Fqn name, Object key, Object value)
          Puts a key and value into the attribute map of a given node.
 void put(List<Modification> modifications)
          Does nothing; replication handles put.
 void remove(Fqn name)
          Does nothing; replication handles removal.
 Object remove(Fqn name, Object key)
          Fetches the remove value, does not remove.
 void removeData(Fqn name)
          Does nothing; replication handles removal.
 void rollback(Object tx)
          Does nothing.
 void setCommandsFactory(CommandsFactory commandsFactory)
           
 void setConfig(CacheLoaderConfig.IndividualCacheLoaderConfig base)
          Sets the configuration.
 void setRegionManager(RegionManager manager)
          Sets the RegionManager this object should use to manage marshalling/unmarshalling of different regions using different classloaders.
 void storeEntireState(ObjectInputStream is)
          Stores the entire state for this cache by reading it from a provided ObjectInputStream.
 void storeState(Fqn subtree, ObjectInputStream is)
          Stores the given portion of the cache tree's state in secondary storage.
 
Methods inherited from class org.jboss.cache.loader.AbstractCacheLoader
create, destroy, doMarshall, doUnmarshall, getMarshaller, getNodeDataList, loadStateHelper, move, put, regionAwareMarshall, regionAwareUnmarshall, setCache, start, stop, storeStateHelper
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ClusteredCacheLoader

public ClusteredCacheLoader()
Method Detail

isCacheReady

protected boolean isCacheReady()
A test to check whether the cache is in its started state. If not, calls should not be made as the channel may not have properly started, blocks due to state transfers may be in progress, etc.

Returns:
true if the cache is in its STARTED state.

setCommandsFactory

public void setCommandsFactory(CommandsFactory commandsFactory)

setConfig

public void setConfig(CacheLoaderConfig.IndividualCacheLoaderConfig base)
Sets the configuration. A property timeout is used as the timeout value.

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.

getChildrenNames

public Set getChildrenNames(Fqn fqn)
                     throws Exception
Description copied from interface: CacheLoader
Returns a set of children node names. All names are relative to this parent Fqn. Returns null if the named node is not found or there are no children. The returned set must not be modifiable. Implementors can use Collections.unmodifiableSet(java.util.Set) to make the set unmodifiable.

Implementors may impose restrictions on the contents of an Fqn (such as Strings-only) and as such, indirectly impose the same restriction on the contents of a Set returned by getChildrenNames().

Parameters:
fqn - 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
Description copied from interface: CacheLoader
Returns all keys and values from the persistent store, given a Fqn

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

get0

protected Map get0(Fqn name)
            throws Exception
Throws:
Exception

exists

public boolean exists(Fqn name)
               throws Exception
Description copied from interface: CacheLoader
Returns true if the CacheLoader has a node with a Fqn.

Returns:
true if node exists, false otherwise
Throws:
Exception

put

public Object put(Fqn name,
                  Object key,
                  Object value)
           throws Exception
Description copied from interface: CacheLoader
Puts a key and value into the attribute map of a given node. If the node does not exist, all parent nodes from the root down are created automatically. Returns the old value.

Throws:
Exception

put

public void put(Fqn name,
                Map attributes)
         throws Exception
Does nothing; replication handles put.

Parameters:
name - The fully qualified name of the node
attributes - A Map of attributes. Can be null
Throws:
Exception

put

public void put(List<Modification> modifications)
         throws Exception
Does nothing; replication handles put.

Specified by:
put in interface CacheLoader
Overrides:
put in class AbstractCacheLoader
Parameters:
modifications - A List of modifications
Throws:
Exception

remove

public Object remove(Fqn name,
                     Object key)
              throws Exception
Fetches the remove value, does not remove. Replication handles removal.

Throws:
Exception

remove

public void remove(Fqn name)
            throws Exception
Does nothing; replication handles removal.

Parameters:
name - the Fqn of the node
Throws:
Exception

removeData

public void removeData(Fqn name)
                throws Exception
Does nothing; replication handles removal.

Parameters:
name - the Fqn of the node
Throws:
Exception

prepare

public void prepare(Object tx,
                    List modifications,
                    boolean one_phase)
             throws Exception
Does nothing.

Specified by:
prepare in interface CacheLoader
Overrides:
prepare in class AbstractCacheLoader
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
one_phase - 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:
Exception

commit

public void commit(Object tx)
            throws Exception
Does nothing.

Specified by:
commit in interface CacheLoader
Overrides:
commit in class AbstractCacheLoader
Parameters:
tx - transaction to commit
Throws:
Exception

rollback

public void rollback(Object tx)
Does nothing.

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

loadEntireState

public void loadEntireState(ObjectOutputStream os)
                     throws Exception
Description copied from interface: CacheLoader
Fetches the entire state for this cache from secondary storage (disk, database) and writes it to a provided ObjectOutputStream. State written to the provided ObjectOutputStream parameter is used for initialization of a new CacheImpl instance. When the state gets transferred to the new cache instance its cacheloader calls CacheLoader.storeEntireState(ObjectInputStream)

Implementations of this method should not catch any exception or close the given ObjectOutputStream parameter. In order to ensure cacheloader interoperability contents of the cache are written to the ObjectOutputStream as a sequence of NodeData objects.

Default implementation is provided by AbstractCacheLoader and ensures cacheloader interoperability. Implementors are encouraged to consider extending AbstractCacheLoader prior to implementing completely custom cacheloader.

Specified by:
loadEntireState in interface CacheLoader
Overrides:
loadEntireState in class AbstractCacheLoader
Parameters:
os - ObjectOutputStream to write state
Throws:
Exception
See Also:
AbstractCacheLoader.loadEntireState(ObjectOutputStream), NodeData

loadState

public void loadState(Fqn subtree,
                      ObjectOutputStream os)
               throws Exception
Description copied from interface: CacheLoader
Fetches a portion of the state for this cache from secondary storage (disk, database) and writes it to a provided ObjectOutputStream. State written to the provided ObjectOutputStream parameter is used for activation of a portion of a new CacheImpl instance. When the state gets transferred to the new cache instance its cacheloader calls CacheLoader.storeState(Fqn,ObjectInputStream).

Implementations of this method should not catch any exception or close the given ObjectOutputStream parameter. In order to ensure cacheloader interoperability contents of the cache are written to the ObjectOutputStream as a sequence of NodeData objects.

Default implementation is provided by AbstractCacheLoader and ensures cacheloader interoperability. Implementors are encouraged to consider extending AbstractCacheLoader prior to implementing completely custom cacheloader.

Specified by:
loadState in interface CacheLoader
Overrides:
loadState in class AbstractCacheLoader
Parameters:
subtree - Fqn naming the root (i.e. highest level parent) node of the subtree for which state is requested.
os - ObjectOutputStream to write state
Throws:
Exception
See Also:
AbstractCacheLoader.loadState(Fqn,ObjectOutputStream), Region.activate(), NodeData

storeEntireState

public void storeEntireState(ObjectInputStream is)
                      throws Exception
Description copied from interface: CacheLoader
Stores the entire state for this cache by reading it from a provided ObjectInputStream. The state was provided to this cache by calling CacheLoader.loadEntireState(ObjectOutputStream)} on some other cache instance. State currently in storage gets overwritten.

Implementations of this method should not catch any exception or close the given ObjectInputStream parameter. In order to ensure cacheloader interoperability contents of the cache are read from the ObjectInputStream as a sequence of NodeData objects.

Default implementation is provided by AbstractCacheLoader and ensures cacheloader interoperability. Implementors are encouraged to consider extending AbstractCacheLoader prior to implementing completely custom cacheloader.

Specified by:
storeEntireState in interface CacheLoader
Overrides:
storeEntireState in class AbstractCacheLoader
Parameters:
is - ObjectInputStream to read state
Throws:
Exception
See Also:
AbstractCacheLoader.storeEntireState(ObjectInputStream), NodeData

storeState

public void storeState(Fqn subtree,
                       ObjectInputStream is)
                throws Exception
Description copied from interface: CacheLoader
Stores the given portion of the cache tree's state in secondary storage. Overwrite whatever is currently in secondary storage. If the transferred state has Fqns equal to or children of parameter subtree, then no special behavior is required. Otherwise, ensure that the state is integrated under the given subtree. Typically in the latter case subtree would be the Fqn of the buddy backup region for a buddy group; e.g.

If the the transferred state had Fqns starting with "/a" and subtree was "/_BUDDY_BACKUP_/192.168.1.2:5555" then the state should be stored in the local persistent store under "/_BUDDY_BACKUP_/192.168.1.2:5555/a"

Implementations of this method should not catch any exception or close the given ObjectInputStream parameter. In order to ensure cacheloader interoperability contents of the cache are read from the ObjectInputStream as a sequence of NodeData objects.

Default implementation is provided by AbstractCacheLoader and ensures cacheloader interoperability. Implementors are encouraged to consider extending AbstractCacheLoader prior to implementing completely custom cacheloader.

Specified by:
storeState in interface CacheLoader
Overrides:
storeState in class AbstractCacheLoader
Parameters:
subtree - Fqn naming the root (i.e. highest level parent) node of the subtree included in state. If the Fqns of the data included in state are not already children of subtree, then their Fqns should be altered to make them children of subtree before they are persisted.
is - ObjectInputStream to read state
Throws:
Exception
See Also:
AbstractCacheLoader.storeState(Fqn,ObjectInputStream), NodeData

setRegionManager

public void setRegionManager(RegionManager manager)
Description copied from interface: CacheLoader
Sets the RegionManager this object should use to manage marshalling/unmarshalling of different regions using different classloaders.

NOTE: This method is only intended to be used by the CacheSPI instance this cache loader is associated with.

Specified by:
setRegionManager in interface CacheLoader
Overrides:
setRegionManager in class AbstractCacheLoader
Parameters:
manager - the region manager to use, or null.


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