org.jboss.cache.loader
Class DelegatingCacheLoader

java.lang.Object
  extended by org.jboss.cache.loader.DelegatingCacheLoader
All Implemented Interfaces:
CacheLoader, org.jboss.system.Service
Direct Known Subclasses:
LocalDelegatingCacheLoader, RmiDelegatingCacheLoader, RpcDelegatingCacheLoader, TcpDelegatingCacheLoader

public abstract class DelegatingCacheLoader
extends java.lang.Object
implements CacheLoader

CacheLoader implementation which delegates to another TreeCache. This allows to stack caches on top of each other, allowing for hierarchical cache levels. For example, first level cache delegates to a second level cache, which delegates to a persistent cache.

Version:
$Id: DelegatingCacheLoader.java,v 1.8 2006/01/17 15:31:21 bela Exp $
Author:
Bela Ban, Daniel Gredler

Field Summary
static int delegateExists
           
static int delegateGet
           
static int delegateGetChildrenNames
           
static int delegateGetKey
           
static int delegateLoadEntireState
           
static int delegatePut
           
static int delegatePutKeyVal
           
static int delegateRemove
           
static int delegateRemoveData
           
static int delegateRemoveKey
           
static int delegateStoreEntireState
           
static int putList
           
 
Constructor Summary
DelegatingCacheLoader()
           
 
Method Summary
 void commit(java.lang.Object tx)
          Commits the transaction.
 void create()
           
protected abstract  boolean delegateExists(Fqn name)
           
protected abstract  java.util.Map delegateGet(Fqn name)
           
protected abstract  java.util.Set delegateGetChildrenNames(Fqn fqn)
           
protected abstract  byte[] delegateLoadEntireState()
           
protected abstract  void delegatePut(Fqn name, java.util.Map attributes)
           
protected abstract  java.lang.Object delegatePut(Fqn name, java.lang.Object key, java.lang.Object value)
           
protected abstract  void delegatePut(java.util.List modifications)
           
protected abstract  void delegateRemove(Fqn name)
           
protected abstract  java.lang.Object delegateRemove(Fqn name, java.lang.Object key)
           
protected abstract  void delegateRemoveData(Fqn name)
           
protected abstract  void delegateStoreEntireState(byte[] state)
           
 void destroy()
           
 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 fully qualified name.
 java.util.Set getChildrenNames(Fqn fqn)
          Returns a set of children node names as Strings.
 byte[] loadEntireState()
          Fetches the entire state for this cache from secondary storage (disk, DB) and returns it as a byte buffer.
 void prepare(java.lang.Object tx, java.util.List 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.
 void put(Fqn fqn, java.util.Map attributes, boolean erase)
           
 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 modifications)
          Applies all modifications to the backend store.
 void remove(Fqn name)
          Removes the given node and all its subnodes.
 java.lang.Object remove(Fqn name, java.lang.Object key)
          Removes the given key and value from the attributes of the given node.
 void removeData(Fqn name)
          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.
abstract  void setCache(TreeCache c)
          Sets the TreeCache that is maintaining this CacheLoader.
abstract  void setConfig(java.util.Properties props)
          Sets the configuration.
 void start()
           
 void stop()
           
 void storeEntireState(byte[] state)
          Stores the given state in secondary storage.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

delegateGetChildrenNames

public static final int delegateGetChildrenNames
See Also:
Constant Field Values

delegateGetKey

public static final int delegateGetKey
See Also:
Constant Field Values

delegateGet

public static final int delegateGet
See Also:
Constant Field Values

delegateExists

public static final int delegateExists
See Also:
Constant Field Values

delegatePutKeyVal

public static final int delegatePutKeyVal
See Also:
Constant Field Values

delegatePut

public static final int delegatePut
See Also:
Constant Field Values

delegateRemoveKey

public static final int delegateRemoveKey
See Also:
Constant Field Values

delegateRemove

public static final int delegateRemove
See Also:
Constant Field Values

delegateRemoveData

public static final int delegateRemoveData
See Also:
Constant Field Values

delegateLoadEntireState

public static final int delegateLoadEntireState
See Also:
Constant Field Values

delegateStoreEntireState

public static final int delegateStoreEntireState
See Also:
Constant Field Values

putList

public static final int putList
See Also:
Constant Field Values
Constructor Detail

DelegatingCacheLoader

public DelegatingCacheLoader()
Method Detail

setConfig

public abstract 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 abstract 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
Description copied from interface: CacheLoader
Returns a set of children node names as Strings. 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(Set) to make the set unmodifiable.

Specified by:
getChildrenNames in interface CacheLoader
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 fully qualified name. NOTE that the expected return value of this method has changed from JBossCache 1.2.x and before! This will affect cache loaders written prior to JBossCache 1.3.0 and such implementations should be checked for compliance with the behaviour expected.

Specified by:
get in interface CacheLoader
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.

Specified by:
exists in interface CacheLoader
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.

Specified by:
put in interface CacheLoader
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

Specified by:
put in interface CacheLoader
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(Fqn fqn,
                java.util.Map attributes,
                boolean erase)
         throws java.lang.Exception
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
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.

Specified by:
remove in interface CacheLoader
Throws:
java.lang.Exception

remove

public void remove(Fqn name)
            throws java.lang.Exception
Description copied from interface: CacheLoader
Removes the given node and all its subnodes.

Specified by:
remove in interface CacheLoader
Throws:
java.lang.Exception

removeData

public void removeData(Fqn name)
                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.

Specified by:
removeData in interface CacheLoader
Throws:
java.lang.Exception

prepare

public void prepare(java.lang.Object tx,
                    java.util.List 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 coresponding SQL statements against the DB (statements derived from modifications)
For non-transactional CacheLoader (e.g. file-based), this could be a null operation.

Specified by:
prepare in interface CacheLoader
Parameters:
tx - The transaction, just used as a hashmap key
modifications - List, a list of all modifications within 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
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
Parameters:
tx - transaction to roll back

loadEntireState

public byte[] loadEntireState()
                       throws java.lang.Exception
Description copied from interface: CacheLoader
Fetches the entire state for this cache from secondary storage (disk, DB) and returns it as a byte buffer. This is for initialization of a new cache from a remote cache. The new cache would then call CacheLoader.storeEntireState(byte[]).

Specified by:
loadEntireState in interface CacheLoader
Throws:
java.lang.Exception

storeEntireState

public void storeEntireState(byte[] state)
                      throws java.lang.Exception
Description copied from interface: CacheLoader
Stores the given state in secondary storage. Overwrites whatever is currently in storage.

Specified by:
storeEntireState in interface CacheLoader
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

delegateGetChildrenNames

protected abstract java.util.Set delegateGetChildrenNames(Fqn fqn)
                                                   throws java.lang.Exception
Throws:
java.lang.Exception

delegateGet

protected abstract java.util.Map delegateGet(Fqn name)
                                      throws java.lang.Exception
Throws:
java.lang.Exception

delegateExists

protected abstract boolean delegateExists(Fqn name)
                                   throws java.lang.Exception
Throws:
java.lang.Exception

delegatePut

protected abstract java.lang.Object delegatePut(Fqn name,
                                                java.lang.Object key,
                                                java.lang.Object value)
                                         throws java.lang.Exception
Throws:
java.lang.Exception

delegatePut

protected abstract void delegatePut(Fqn name,
                                    java.util.Map attributes)
                             throws java.lang.Exception
Throws:
java.lang.Exception

delegateRemove

protected abstract java.lang.Object delegateRemove(Fqn name,
                                                   java.lang.Object key)
                                            throws java.lang.Exception
Throws:
java.lang.Exception

delegateRemove

protected abstract void delegateRemove(Fqn name)
                                throws java.lang.Exception
Throws:
java.lang.Exception

delegateRemoveData

protected abstract void delegateRemoveData(Fqn name)
                                    throws java.lang.Exception
Throws:
java.lang.Exception

delegateLoadEntireState

protected abstract byte[] delegateLoadEntireState()
                                           throws java.lang.Exception
Throws:
java.lang.Exception

delegateStoreEntireState

protected abstract void delegateStoreEntireState(byte[] state)
                                          throws java.lang.Exception
Throws:
java.lang.Exception

delegatePut

protected abstract void delegatePut(java.util.List modifications)
                             throws java.lang.Exception
Throws:
java.lang.Exception


Copyright 1998-2005 JBoss Inc . All Rights Reserved.