org.dmd.dmp.server.servlet.base.plugins

Class BasicCachePlugin

java.lang.Object

org.dmd.dmp.server.servlet.base.DmpServletPlugin

org.dmd.dmp.server.servlet.base.plugins.BasicCachePlugin

All Implemented Interfaces:

Runnable, org.dmd.dmc.DmcNameClashResolverIF, org.dmd.dmc.DmcNameResolverIF, org.dmd.dmc.DmcNameResolverWithClashSupportIF, CacheIF, org.dmd.util.parsing.DmcUncheckedOIFHandlerIF

public class BasicCachePlugin
extends DmpServletPlugin
implements CacheIF, Runnable, org.dmd.util.parsing.DmcUncheckedOIFHandlerIF, org.dmd.dmc.DmcNameClashResolverIF, org.dmd.dmc.DmcNameResolverWithClashSupportIF

The BasicCachePlugin provides the implementation of a cache of objects that are the focus of your data management application. The design of a cache is often quite application specific, so the way that this cache works may not be suitable to your needs; it is merely an example of how such a cache could work.

The cache supports the basic CRUDE mechanism (not just CRUD - see the Dark Matter Data Overview page - http://code.google.com/p/dark-matter-data/wiki/DMDOverview). The 'E' stands for events.

Field Summary

Fields inherited from class org.dmd.dmp.server.servlet.base.DmpServletPlugin

cache, pluginConfig, pluginManager, servlet

Constructor Summary

Constructors

Constructor and Description
BasicCachePlugin()

Method Summary

Modifier and Type	Method and Description
Collection<org.dmd.dmw.DmwNamedObjectWrapper>	addListener(CacheListener listener) Adds the specified listener to the cache.
void	addNameGenerator(NameGeneratorIF ng) Adds the specified name generator to the cache.
void	addObject(org.dmd.dmw.DmwNamedObjectWrapper obj) This method is used to add a new object to the cache during the initialization phase of the plugins.
void	create(org.dmd.dmw.DmwNamedObjectWrapper obj, org.dmd.dmp.server.extended.Request request)
void	createAndNotify(org.dmd.dmw.DmwNamedObjectWrapper obj)
void	delete(org.dmd.dmc.DmcObjectName name, org.dmd.dmp.server.extended.Request request)
void	delete(org.dmd.dmw.DmwNamedObjectWrapper obj)
void	deleteAndNotify(org.dmd.dmc.DmcObjectName name)
void	deleteAndNotify(org.dmd.dmw.DmwNamedObjectWrapper obj)
void	dumpObjects(PrintStream ps) Dumps all cached objects to the specified PrintStream.
org.dmd.dmc.DmcObject	findNamedDMO(org.dmd.dmc.DmcObjectName name)
org.dmd.dmc.DmcNamedObjectIF	findNamedObject(org.dmd.dmc.DmcObjectName name)
org.dmd.dmc.DmcNamedObjectIF	findNamedObject(org.dmd.dmc.DmcObjectName name, int attributeID)
org.dmd.dmc.DmcNamedObjectIF	findNamedObjectMayClash(org.dmd.dmc.DmcObject object, org.dmd.dmc.DmcObjectName name, org.dmd.dmc.DmcNameClashResolverIF resolver, org.dmd.dmc.DmcAttributeInfo ai)
org.dmd.dmw.DmwNamedObjectWrapper	get(org.dmd.dmc.DmcObjectName name) Returns the specified object if it exists.
Collection<org.dmd.dmw.DmwHierarchicObjectWrapper>	getAll(org.dmd.dmc.DmcHierarchicObjectName name)
Collection<org.dmd.dmw.DmwNamedObjectWrapper>	getIndex(org.dmd.dmc.DmcClassInfo ci)
int	getIndexSize(org.dmd.dmc.DmcClassInfo ci)
Collection<org.dmd.dmw.DmwHierarchicObjectWrapper>	getNext(org.dmd.dmc.DmcHierarchicObjectName name)
long	getNextListenerID() Returns the next unique listener ID.
void	handleObject(org.dmd.dmc.util.DmcUncheckedObject uco, String infile, int lineNumber)
boolean	hasIndex(org.dmd.dmc.DmcClassInfo dci)
protected void	init() Derived classes should perform any initialization logic required.
void	maintainIndex(org.dmd.dmc.DmcClassInfo ci) Indexing is a generally useful mechanism that allows for rapid access to objects of a particular type.
void	preInit()
protected void	processCreateRequest(org.dmd.dmp.server.extended.CreateRequest request)
protected void	processDeleteRequest(org.dmd.dmp.server.extended.DeleteRequest request)
protected void	processSetRequest(org.dmd.dmp.server.extended.SetRequest request)
void	queueCreateRequest(org.dmd.dmp.server.extended.CreateRequest request) Queues a CreateRequest for processing in the order in which it arrived.
void	queueDeleteRequest(org.dmd.dmp.server.extended.DeleteRequest request) Queues a DeleteRequest for processing in the order in which it arrived.
void	queueEvent(org.dmd.dmp.server.extended.DMPEvent event) Queues an event from a remote source for processing by the cache.
void	queueSetRequest(org.dmd.dmp.server.extended.SetRequest request) Queues a SetRequest for processing in the order in which it arrived.
CacheRegistration	register(SessionIF session) If you are going to perform operations against a cache, you will need a unique registration against that cache.
void	removeListener(CacheListener listener) Removes the specified listener from the cache.
void	removeListenersForSession(SessionIF session) Removes all cache listeners associated with the specified session.
org.dmd.dmc.DmcNamedObjectIF	resolveClash(org.dmd.dmc.DmcObject obj, org.dmd.dmc.DmcAttributeInfo ai, org.dmd.dmc.DmcNameClashObjectSet<?> ncos)
void	run()
void	set(org.dmd.dmc.DmcObjectName name, org.dmd.dms.generated.types.DmcTypeModifierMV modifier, org.dmd.dmp.server.extended.Request request)
void	set(org.dmd.dmw.DmwNamedObjectWrapper obj)
void	setAndNotify(org.dmd.dmw.DmwNamedObjectWrapper obj)
void	shutdown() When the servlet is destroyed, the shutdown() method is called on all plugins.
void	start() After all plugins are initialized, the start method is called on all plugins in the same implied order.

Methods inherited from class org.dmd.dmp.server.servlet.base.DmpServletPlugin

getID, getPluginName, setManagerAndConfig

Methods inherited from class java.lang.Object

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

Constructor Detail

BasicCachePlugin

public BasicCachePlugin()

Method Detail

preInit

public void preInit()
             throws org.dmd.util.exceptions.ResultException,
                    org.dmd.dmc.DmcValueException

Overrides:

preInit in class DmpServletPlugin

Throws:

org.dmd.util.exceptions.ResultException

org.dmd.dmc.DmcValueException

init

protected void init()
             throws org.dmd.util.exceptions.ResultException,
                    org.dmd.dmc.DmcValueException,
                    org.dmd.dmc.rules.DmcRuleExceptionSet,
                    org.dmd.dmc.DmcNameClashException

Description copied from class: DmpServletPlugin

Derived classes should perform any initialization logic required. If a plugin has indicated that it depends on another plugin, it is safe to assume that the other plugin has been initialized.

Overrides:

init in class DmpServletPlugin

Throws:

org.dmd.dmc.rules.DmcRuleExceptionSet

org.dmd.dmc.DmcNameClashException

org.dmd.util.exceptions.ResultException

org.dmd.dmc.DmcValueException

start

public void start()
           throws org.dmd.util.exceptions.ResultException,
                  org.dmd.dmc.DmcValueException

Description copied from class: DmpServletPlugin

After all plugins are initialized, the start method is called on all plugins in the same implied order.

Overrides:

start in class DmpServletPlugin

Throws:

org.dmd.util.exceptions.ResultException

org.dmd.dmc.DmcValueException

shutdown

public void shutdown()

Description copied from class: DmpServletPlugin

When the servlet is destroyed, the shutdown() method is called on all plugins.

Overrides:

shutdown in class DmpServletPlugin

run

public void run()

Specified by:

run in interface Runnable

processSetRequest

protected void processSetRequest(org.dmd.dmp.server.extended.SetRequest request)

processCreateRequest

protected void processCreateRequest(org.dmd.dmp.server.extended.CreateRequest request)

processDeleteRequest

protected void processDeleteRequest(org.dmd.dmp.server.extended.DeleteRequest request)

addObject

public void addObject(org.dmd.dmw.DmwNamedObjectWrapper obj)
               throws org.dmd.util.exceptions.ResultException

Description copied from interface: CacheIF

This method is used to add a new object to the cache during the initialization phase of the plugins. The object is added to either a flat name space or the hierarchic namespace, depending on whether the name is hierarchic or not.

Specified by:

addObject in interface CacheIF

Parameters:

obj - the object to be added.

Throws:

org.dmd.util.exceptions.ResultException

dumpObjects

public void dumpObjects(PrintStream ps)

Description copied from interface: CacheIF

Dumps all cached objects to the specified PrintStream.

Specified by:

dumpObjects in interface CacheIF

get

public org.dmd.dmw.DmwNamedObjectWrapper get(org.dmd.dmc.DmcObjectName name)

Description copied from interface: CacheIF

Returns the specified object if it exists.

Specified by:

get in interface CacheIF

Parameters:

name - the name of the object to be retrieved.

Returns:

the specified object or null if it doesn't exist.

getNext

public Collection<org.dmd.dmw.DmwHierarchicObjectWrapper> getNext(org.dmd.dmc.DmcHierarchicObjectName name)

Specified by:

getNext in interface CacheIF

Parameters:

name - the name of the parent object.

Returns:

the children of the specified object

getAll

public Collection<org.dmd.dmw.DmwHierarchicObjectWrapper> getAll(org.dmd.dmc.DmcHierarchicObjectName name)

Specified by:

getAll in interface CacheIF

Parameters:

name - the root of the tree to be retrieved

Returns:

the entire tree of hierarchic objects, include the root object.

create

public void create(org.dmd.dmw.DmwNamedObjectWrapper obj,
                   org.dmd.dmp.server.extended.Request request)

Specified by:

create in interface CacheIF

createAndNotify

public void createAndNotify(org.dmd.dmw.DmwNamedObjectWrapper obj)

Specified by:

createAndNotify in interface CacheIF

delete

public void delete(org.dmd.dmw.DmwNamedObjectWrapper obj)

Specified by:

delete in interface CacheIF

delete

public void delete(org.dmd.dmc.DmcObjectName name,
                   org.dmd.dmp.server.extended.Request request)
            throws org.dmd.util.exceptions.ResultException

Specified by:

delete in interface CacheIF

Throws:

org.dmd.util.exceptions.ResultException

deleteAndNotify

public void deleteAndNotify(org.dmd.dmw.DmwNamedObjectWrapper obj)

Specified by:

deleteAndNotify in interface CacheIF

deleteAndNotify

public void deleteAndNotify(org.dmd.dmc.DmcObjectName name)

Specified by:

deleteAndNotify in interface CacheIF

set

public void set(org.dmd.dmw.DmwNamedObjectWrapper obj)

Specified by:

set in interface CacheIF

setAndNotify

public void setAndNotify(org.dmd.dmw.DmwNamedObjectWrapper obj)

Specified by:

setAndNotify in interface CacheIF

set

public void set(org.dmd.dmc.DmcObjectName name,
                org.dmd.dms.generated.types.DmcTypeModifierMV modifier,
                org.dmd.dmp.server.extended.Request request)
         throws org.dmd.util.exceptions.ResultException

Specified by:

set in interface CacheIF

Throws:

org.dmd.util.exceptions.ResultException

maintainIndex

public void maintainIndex(org.dmd.dmc.DmcClassInfo ci)

Description copied from interface: CacheIF

Indexing is a generally useful mechanism that allows for rapid access to objects of a particular type. This method should be overloaded to add an index for the specified class. This mechanism should work for both concrete and abstract classes since it is easy to determine if a DMO is an instance of a particular base class using the DmcClassInfo.isInstanceOf() method.

Specified by:

maintainIndex in interface CacheIF

Parameters:

ci - The class info of the class from the DMSAG

hasIndex

public boolean hasIndex(org.dmd.dmc.DmcClassInfo dci)

Specified by:

hasIndex in interface CacheIF

Parameters:

dci - the class to check for.

Returns:

true if there's an index for the class and false otherwise.

getIndexSize

public int getIndexSize(org.dmd.dmc.DmcClassInfo ci)

Specified by:

getIndexSize in interface CacheIF

Parameters:

ci - the class whose index you want to check.

Returns:

The number of entries in the index.

getIndex

public Collection<org.dmd.dmw.DmwNamedObjectWrapper> getIndex(org.dmd.dmc.DmcClassInfo ci)

Specified by:

getIndex in interface CacheIF

Parameters:

ci - the class for which you want the indexed values.

Returns:

the value in the index.

handleObject

public void handleObject(org.dmd.dmc.util.DmcUncheckedObject uco,
                         String infile,
                         int lineNumber)
                  throws org.dmd.util.exceptions.ResultException,
                         org.dmd.dmc.DmcValueException

Specified by:

handleObject in interface org.dmd.util.parsing.DmcUncheckedOIFHandlerIF

Throws:

org.dmd.util.exceptions.ResultException

org.dmd.dmc.DmcValueException

register

public CacheRegistration register(SessionIF session)

Description copied from interface: CacheIF

If you are going to perform operations against a cache, you will need a unique registration against that cache.

Specified by:

register in interface CacheIF

Parameters:

session - the session that's registering against the cache

Returns:

a registration against the cache.

findNamedDMO

public org.dmd.dmc.DmcObject findNamedDMO(org.dmd.dmc.DmcObjectName name)

Specified by:

findNamedDMO in interface org.dmd.dmc.DmcNameResolverIF

findNamedObject

public org.dmd.dmc.DmcNamedObjectIF findNamedObject(org.dmd.dmc.DmcObjectName name)

Specified by:

findNamedObject in interface org.dmd.dmc.DmcNameResolverIF

findNamedObject

public org.dmd.dmc.DmcNamedObjectIF findNamedObject(org.dmd.dmc.DmcObjectName name,
                                                    int attributeID)

Specified by:

findNamedObject in interface org.dmd.dmc.DmcNameResolverIF

queueSetRequest

public void queueSetRequest(org.dmd.dmp.server.extended.SetRequest request)

Description copied from interface: CacheIF

Queues a SetRequest for processing in the order in which it arrived.

Specified by:

queueSetRequest in interface CacheIF

Parameters:

request - the request to be processed

queueCreateRequest

public void queueCreateRequest(org.dmd.dmp.server.extended.CreateRequest request)

Description copied from interface: CacheIF

Queues a CreateRequest for processing in the order in which it arrived.

Specified by:

queueCreateRequest in interface CacheIF

Parameters:

request - the request to be processed

queueDeleteRequest

public void queueDeleteRequest(org.dmd.dmp.server.extended.DeleteRequest request)

Description copied from interface: CacheIF

Queues a DeleteRequest for processing in the order in which it arrived.

Specified by:

queueDeleteRequest in interface CacheIF

Parameters:

request - the request to be processed

queueEvent

public void queueEvent(org.dmd.dmp.server.extended.DMPEvent event)

Description copied from interface: CacheIF

Queues an event from a remote source for processing by the cache. This is required in cases where the web server is acting has a front for one or more other data sources.

Specified by:

queueEvent in interface CacheIF

Parameters:

event - the event to be processed

getNextListenerID

public long getNextListenerID()

Returns the next unique listener ID.

Specified by:

getNextListenerID in interface CacheIF

Returns:

the next unique identifier for a newly created CacheListener.

addListener

public Collection<org.dmd.dmw.DmwNamedObjectWrapper> addListener(CacheListener listener)

Description copied from interface: CacheIF

Adds the specified listener to the cache. The exact behaviour of the listener is cache implementation specific.

Specified by:

addListener in interface CacheIF

Parameters:

listener - the cache listener

Returns:

a set of objects that meet the listener criteria

removeListener

public void removeListener(CacheListener listener)

Description copied from interface: CacheIF

Removes the specified listener from the cache.

Specified by:

removeListener in interface CacheIF

Parameters:

listener - the listener to be removed.

addNameGenerator

public void addNameGenerator(NameGeneratorIF ng)

Description copied from interface: CacheIF

Adds the specified name generator to the cache. Generators are used to set the unique name of objects that are created via the cache.

Specified by:

addNameGenerator in interface CacheIF

findNamedObjectMayClash

public org.dmd.dmc.DmcNamedObjectIF findNamedObjectMayClash(org.dmd.dmc.DmcObject object,
                                                            org.dmd.dmc.DmcObjectName name,
                                                            org.dmd.dmc.DmcNameClashResolverIF resolver,
                                                            org.dmd.dmc.DmcAttributeInfo ai)
                                                     throws org.dmd.dmc.DmcValueException

Specified by:

findNamedObjectMayClash in interface org.dmd.dmc.DmcNameResolverWithClashSupportIF

Throws:

org.dmd.dmc.DmcValueException

resolveClash

public org.dmd.dmc.DmcNamedObjectIF resolveClash(org.dmd.dmc.DmcObject obj,
                                                 org.dmd.dmc.DmcAttributeInfo ai,
                                                 org.dmd.dmc.DmcNameClashObjectSet<?> ncos)
                                          throws org.dmd.dmc.DmcValueException

Specified by:

resolveClash in interface org.dmd.dmc.DmcNameClashResolverIF

Throws:

org.dmd.dmc.DmcValueException

removeListenersForSession

public void removeListenersForSession(SessionIF session)

Description copied from interface: CacheIF

Removes all cache listeners associated with the specified session.

Specified by:

removeListenersForSession in interface CacheIF