DelegatingCacheLoader (JBossCache API) - JBoss 4.0.1 sp1 Cache API Documentation 英文版文档

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org.jboss.cache.loader
Class DelegatingCacheLoader

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

All Implemented Interfaces:: CacheLoader, org.jboss.system.Service

public class DelegatingCacheLoader
extends 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. Sample code:

 TreeCache firstLevel=new TreeCache();
 TreeCache secondLevel=new TreeCache();
 DelegatingCacheLoader l=new DelegatingCacheLoader(secondLevel);
 l.setCache(firstLevel);
 firstLevel.setCacheLoader(l);
 secondLevel.start();
 firstLevel.start();

Version:: $Id: DelegatingCacheLoader.java,v 1.2 2004/11/30 14:06:07 belaban Exp $
Author:: Bela Ban

Constructor Summary

DelegatingCacheLoader(TreeCache delegate)


Method Summary

void commit(Object tx)
          Commit the transaction.

void create()


void destroy()


boolean exists(Fqn name)
          Checks whether the CacheLoader has a node with Fqn

Map get(Fqn name)
          Returns all keys and values from the persistent store, given a fully qualified name

Object get(Fqn name, Object key)
          Returns the value for a given key.

Set getChildrenNames(Fqn fqn)
          Returns a list of children names, all names are relative.

byte[] loadEntireState()
          Fetch the entire state for this cache from secondary storage (disk, DB) and return it as a byte buffer.

void prepare(Object tx, List modifications, boolean one_phase)
          Prepare the modifications.

void put(Fqn name, Map attributes)
          Inserts all elements of attributes into the attributes hashmap of the given node, overwriting existing attributes, but not clearing the existing hashmap before insertion (making it a union of existing and new attributes) If the node does not exist, all parent nodes from the root down are created automatically

void put(Fqn fqn, Map attributes, boolean erase)


Object put(Fqn name, Object key, Object value)
          Inserts key and value into the attributes hashmap of the given node.

void put(List modifications)
          Inserts all modifications to the backend store.

void remove(Fqn name)
          Removes the given node.

Object remove(Fqn name, 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

void rollback(Object tx)
          Roll the transaction back.

void setCache(TreeCache c)
          This method allows the CacheLoader to set the TreeCache, therefore allowing the CacheLoader to invoke methods of the TreeCache.

void setConfig(Properties props)
          Sets the configuration.

void start()


void stop()


void storeEntireState(byte[] state)
          Store the given state in secondary storage.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DelegatingCacheLoader

public DelegatingCacheLoader(TreeCache delegate)

Method Detail

setConfig

public void setConfig(Properties props)

Description copied from interface: CacheLoader

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

Specified by:: setConfig in interface CacheLoader

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

setCache

public void setCache(TreeCache c)

Description copied from interface: CacheLoader

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

Parameters:: c - The cache on which this loader works

getChildrenNames

public Set getChildrenNames(Fqn fqn)
                     throws Exception

Description copied from interface: CacheLoader

Returns a list of children names, all names are relative. Returns null if the parent node is not found. The returned set must not be modified, e.g. use Collections.unmodifiableSet(s) to return the result

Specified by:: getChildrenNames in interface CacheLoader

Parameters:: fqn - The FQN of the parent
Returns:: Set. A list of children. Returns null if no children nodes are present, or the parent is not present
Throws:: Exception

get

public Object get(Fqn name,
                  Object key)
           throws Exception

Description copied from interface: CacheLoader

Returns the value for a given key. Returns null if the node doesn't exist, or the value is not bound

Specified by:: get in interface CacheLoader

Parameters:: name -
Returns:
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 fully qualified name

Specified by:: get in interface CacheLoader

Parameters:: name -
Returns:: Map of keys and values for the given node. Returns null if the node was not found, or if the node has no attributes
Throws:: Exception

exists

public boolean exists(Fqn name)
               throws Exception

Description copied from interface: CacheLoader

Checks whether the CacheLoader has a node with Fqn

Specified by:: exists in interface CacheLoader

Parameters:: name -
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

Inserts key and value into the attributes hashmap of the 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:: Exception

put

public void put(Fqn name,
                Map attributes)
         throws Exception

Description copied from interface: CacheLoader

Inserts all elements of attributes into the attributes hashmap of the given node, overwriting existing attributes, but not clearing the existing hashmap before insertion (making it a union of existing and new attributes) 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:: Exception

put

public void put(Fqn fqn,
                Map attributes,
                boolean erase)
         throws Exception

Throws:: Exception

put

public void put(List modifications)
         throws Exception

Description copied from interface: CacheLoader

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

Specified by:: put in interface CacheLoader

Parameters:: modifications - A List of modifications
Throws:: Exception

remove

public Object remove(Fqn name,
                     Object key)
              throws Exception

Description copied from interface: CacheLoader

Removes the given key and value from the attributes of the given node. No-op if node doesn't exist

Specified by:: remove in interface CacheLoader

Throws:: Exception

remove

public void remove(Fqn name)
            throws Exception

Description copied from interface: CacheLoader

Removes the given node. If the node is the root of a subtree, this will recursively remove all subnodes, depth-first

Specified by:: remove in interface CacheLoader

Throws:: Exception

removeData

public void removeData(Fqn name)
                throws Exception

Description copied from interface: CacheLoader

Removes all attributes from a given node, but doesn't delete the node itself

Specified by:: removeData in interface CacheLoader

Parameters:: name -
Throws:: Exception

prepare

public void prepare(Object tx,
                    List modifications,
                    boolean one_phase)
             throws Exception

Description copied from interface: CacheLoader

Prepare the modifications. For example, for a DB-based CacheLoader:

Create a local (JDBC) transaction
Associate the local transaction with tx (tx is the key)
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:: Exception

commit

public void commit(Object tx)
            throws Exception

Description copied from interface: CacheLoader

Commit 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 -
Throws:: Exception

rollback

public void rollback(Object tx)

Description copied from interface: CacheLoader

Roll 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 -

loadEntireState

public byte[] loadEntireState()
                       throws Exception

Description copied from interface: CacheLoader

Fetch the entire state for this cache from secondary storage (disk, DB) and return it as a byte buffer. This is for initialization of a new cache from a remote cache. The new cache would then call storeEntireState().
todo: define binary format for exchanging state

Specified by:: loadEntireState in interface CacheLoader

Throws:: Exception

storeEntireState

public void storeEntireState(byte[] state)
                      throws Exception

Description copied from interface: CacheLoader

Store the given state in secondary storage. Overwrite whatever is currently in seconday storage.

Specified by:: storeEntireState in interface CacheLoader

Throws:: Exception

create

public void create()
            throws Exception

Specified by:: create in interface org.jboss.system.Service

Throws:: Exception

start

public void start()
           throws Exception

Specified by:: start in interface org.jboss.system.Service

Throws:: 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

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Constructor Summary
`DelegatingCacheLoader(TreeCache delegate)`

Method Summary
`void`	`commit(Object tx)` Commit the transaction.
`void`	`create()`
`void`	`destroy()`
`boolean`	`exists(Fqn name)` Checks whether the CacheLoader has a node with Fqn
`Map`	`get(Fqn name)` Returns all keys and values from the persistent store, given a fully qualified name
`Object`	`get(Fqn name, Object key)` Returns the value for a given key.
`Set`	`getChildrenNames(Fqn fqn)` Returns a list of children names, all names are relative.
`byte[]`	`loadEntireState()` Fetch the entire state for this cache from secondary storage (disk, DB) and return it as a byte buffer.
`void`	`prepare(Object tx, List modifications, boolean one_phase)` Prepare the modifications.
`void`	`put(Fqn name, Map attributes)` Inserts all elements of attributes into the attributes hashmap of the given node, overwriting existing attributes, but not clearing the existing hashmap before insertion (making it a union of existing and new attributes) If the node does not exist, all parent nodes from the root down are created automatically
`void`	`put(Fqn fqn, Map attributes, boolean erase)`
`Object`	`put(Fqn name, Object key, Object value)` Inserts key and value into the attributes hashmap of the given node.
`void`	`put(List modifications)` Inserts all modifications to the backend store.
`void`	`remove(Fqn name)` Removes the given node.
`Object`	`remove(Fqn name, 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
`void`	`rollback(Object tx)` Roll the transaction back.
`void`	`setCache(TreeCache c)` This method allows the CacheLoader to set the TreeCache, therefore allowing the CacheLoader to invoke methods of the TreeCache.
`void`	`setConfig(Properties props)` Sets the configuration.
`void`	`start()`
`void`	`stop()`
`void`	`storeEntireState(byte[] state)` Store the given state in secondary storage.

DelegatingCacheLoader (JBossCache API) - JBoss 4.0.1 sp1 Cache API Documentation 英文版文档

org.jboss.cache.loader Class DelegatingCacheLoader

DelegatingCacheLoader

setConfig

setCache

getChildrenNames

get

get

exists

put

put

put

put

remove

remove

removeData

prepare

commit

rollback

loadEntireState

storeEntireState

create

start

stop

destroy

org.jboss.cache.loader
Class DelegatingCacheLoader