org.jboss.cache.loader
Class AbstractDelegatingCacheLoader

java.lang.Object
  extended by org.jboss.cache.loader.AbstractCacheLoader
      extended by org.jboss.cache.loader.AbstractDelegatingCacheLoader
All Implemented Interfaces:
CacheLoader
Direct Known Subclasses:
AsyncCacheLoader, SingletonStoreCacheLoader

public abstract class AbstractDelegatingCacheLoader
extends AbstractCacheLoader

AbstractDelegatingCacheLoader provides standard functionality for a cache loader that simply delegates each operation defined in the cache loader interface to the underlying cache loader, basically acting as a proxy to the real cache loader.

Any cache loader implementation that extends this class would be required to override any of the methods in order to provide a different or added behaviour.

Author:
Galder Zamarreno

Field Summary
 
Fields inherited from class org.jboss.cache.loader.AbstractCacheLoader
cache, regionManager, transactions
 
Constructor Summary
AbstractDelegatingCacheLoader(CacheLoader cl)
           
 
Method Summary
 void commit(java.lang.Object tx)
          Commits the transaction.
 void create()
          Lifecycle method, called when the cache loader is created.
 void destroy()
          Lifecycle method, called when the cache loader is destroyed.
 boolean exists(Fqn name)
          Returns true if the CacheLoader has a node with a Fqn.
 java.util.Map get(Fqn name)
          Returns all keys and values from the persistent store, given a Fqn
 CacheLoader getCacheLoader()
           
 java.util.Set getChildrenNames(Fqn fqn)
          Returns a set of children node names.
 CacheLoaderConfig.IndividualCacheLoaderConfig getConfig()
          Gets the configuration.
 void loadEntireState(java.io.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, java.io.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(java.lang.Object tx, java.util.List<Modification> modifications, boolean one_phase)
          Prepares a list of modifications.
 void put(Fqn name, java.util.Map attributes)
          Puts all entries of the map into the existing map of the given node, overwriting existing keys, but not clearing the existing map before insertion.
 java.lang.Object put(Fqn name, java.lang.Object key, java.lang.Object value)
          Puts a key and value into the attribute map of a given node.
 void put(java.util.List<Modification> modifications)
          Applies all modifications to the backend store.
 void remove(Fqn fqn)
          Removes the given node and all its subnodes, does nothing if the node does not exist.
 java.lang.Object remove(Fqn fqn, java.lang.Object key)
          Removes the given key and value from the attributes of the given node.
 void removeData(Fqn fqn)
          Removes all attributes from a given node, but doesn't delete the node itself or any subnodes.
 void rollback(java.lang.Object tx)
          Rolls the transaction back.
 void setCache(CacheSPI c)
          Sets the CacheSPI that is maintaining this CacheLoader.
 void setCacheLoader(CacheLoader cacheLoader)
           
 void setConfig(CacheLoaderConfig.IndividualCacheLoaderConfig config)
          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 start()
          Lifecycle method, called when the cache loader is started.
 void stop()
          Lifecycle method, called when the cache loader is stopped.
 void storeEntireState(java.io.ObjectInputStream is)
          Stores the entire state for this cache by reading it from a provided ObjectInputStream.
 void storeState(Fqn subtree, java.io.ObjectInputStream is)
          Stores the given portion of the cache tree's state in secondary storage.
 
Methods inherited from class org.jboss.cache.loader.AbstractCacheLoader
getMarshaller, getNodeDataList, loadStateHelper, put
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

AbstractDelegatingCacheLoader

public AbstractDelegatingCacheLoader(CacheLoader cl)
Method Detail

getCacheLoader

public CacheLoader getCacheLoader()

setCacheLoader

public void setCacheLoader(CacheLoader cacheLoader)

setConfig

public void setConfig(CacheLoaderConfig.IndividualCacheLoaderConfig config)
Description copied from interface: CacheLoader
Sets the configuration. This is called before CacheLoader.create() and CacheLoader.start().

Parameters:
config - 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.

setCache

public void setCache(CacheSPI c)
Description copied from interface: CacheLoader
Sets the CacheSPI that is maintaining this CacheLoader. This method allows this CacheLoader to set a reference to the CacheSPI. This method is called be called after the CacheLoader instance has been constructed.

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

getChildrenNames

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

get

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

exists

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

put

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

put

public void put(Fqn name,
                java.util.Map attributes)
         throws java.lang.Exception
Description copied from interface: CacheLoader
Puts all entries of the map into the existing map of the given node, overwriting existing keys, but not clearing the existing map before insertion. This is the same behavior as Map.putAll(java.util.Map). If the node does not exist, all parent nodes from the root down are created automatically

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

put

public void put(java.util.List<Modification> 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
Overrides:
put in class AbstractCacheLoader
Parameters:
modifications - A List of modifications
Throws:
java.lang.Exception

remove

public java.lang.Object remove(Fqn fqn,
                               java.lang.Object key)
                        throws java.lang.Exception
Description copied from interface: CacheLoader
Removes the given key and value from the attributes of the given node. Does nothing if the node doesn't exist Returns the removed value.

Throws:
java.lang.Exception

remove

public void remove(Fqn fqn)
            throws java.lang.Exception
Description copied from interface: CacheLoader
Removes the given node and all its subnodes, does nothing if the node does not exist.

Parameters:
fqn - the Fqn of the node
Throws:
java.lang.Exception

removeData

public void removeData(Fqn fqn)
                throws java.lang.Exception
Description copied from interface: CacheLoader
Removes all attributes from a given node, but doesn't delete the node itself or any subnodes.

Parameters:
fqn - the Fqn of the node
Throws:
java.lang.Exception

prepare

public void prepare(java.lang.Object tx,
                    java.util.List<Modification> modifications,
                    boolean one_phase)
             throws java.lang.Exception
Description copied from interface: CacheLoader
Prepares a list of modifications. For example, for a DB-based CacheLoader:
  1. Create a local (JDBC) transaction
  2. Associate the local transaction with tx (tx is the key)
  3. Execute the corresponding SQL statements against the DB (statements derived from modifications)
For non-transactional CacheLoader (e.g. file-based), the implementation could attempt to implement it's own transactional logic, attempting to write data to a temp location (or memory) and writing it to the proper location upon commit.

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:
java.lang.Exception

commit

public void commit(java.lang.Object tx)
            throws java.lang.Exception
Description copied from interface: CacheLoader
Commits the transaction. A DB-based CacheLoader would look up the local JDBC transaction asociated with tx and commit that transaction. Non-transactional CacheLoaders could simply write the data that was previously saved transiently under the given tx key, to (for example) a file system.

Note this only holds if the previous prepare() did not define

one_phase=true

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

rollback

public void rollback(java.lang.Object tx)
Description copied from interface: CacheLoader
Rolls the transaction back. A DB-based CacheLoader would look up the local JDBC transaction asociated with tx and roll back that transaction.

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

loadEntireState

public void loadEntireState(java.io.ObjectOutputStream os)
                     throws java.lang.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:
java.lang.Exception
See Also:
AbstractCacheLoader.loadEntireState(ObjectOutputStream), NodeData

storeEntireState

public void storeEntireState(java.io.ObjectInputStream is)
                      throws java.lang.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:
java.lang.Exception
See Also:
AbstractCacheLoader.storeEntireState(ObjectInputStream), NodeData

loadState

public void loadState(Fqn subtree,
                      java.io.ObjectOutputStream os)
               throws java.lang.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:
java.lang.Exception
See Also:
AbstractCacheLoader.loadState(Fqn,ObjectOutputStream), Region.activate(), NodeData

storeState

public void storeState(Fqn subtree,
                       java.io.ObjectInputStream is)
                throws java.lang.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:
java.lang.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.

create

public void create()
            throws java.lang.Exception
Description copied from interface: CacheLoader
Lifecycle method, called when the cache loader is created.

Specified by:
create in interface CacheLoader
Overrides:
create in class AbstractCacheLoader
Throws:
java.lang.Exception

start

public void start()
           throws java.lang.Exception
Description copied from interface: CacheLoader
Lifecycle method, called when the cache loader is started.

Specified by:
start in interface CacheLoader
Overrides:
start in class AbstractCacheLoader
Throws:
java.lang.Exception

stop

public void stop()
Description copied from interface: CacheLoader
Lifecycle method, called when the cache loader is stopped.

Specified by:
stop in interface CacheLoader
Overrides:
stop in class AbstractCacheLoader

destroy

public void destroy()
Description copied from interface: CacheLoader
Lifecycle method, called when the cache loader is destroyed.

Specified by:
destroy in interface CacheLoader
Overrides:
destroy in class AbstractCacheLoader