org.jboss.cache.loader
Class ClusteredCacheLoader

java.lang.Object
  org.jboss.cache.loader.AbstractCacheLoader
      org.jboss.cache.loader.ClusteredCacheLoader

All Implemented Interfaces:

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@jboss.org)

Nested Class Summary

static class

ClusteredCacheLoader.ResponseValidityFilter

Field Summary

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

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)
CacheLoaderConfig.IndividualCacheLoaderConfig	getConfig() Gets the configuration.
Set	getChildrenNames(Fqn fqn) Returns a set of children node names.
protected boolean	isCacheReady() A test to check whether the cache is in it's 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	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, put, regionAwareMarshall, regionAwareUnmarshall, setCache, start, stop

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 it's 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 it's STARTED state.

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 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.

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.