org.gcube.common.core.utils.handlers

Class GCUBEHandler<HANDLED>

java.lang.Object

org.gcube.common.core.utils.handlers.GCUBEHandler<HANDLED>

Type Parameters:

HANDLED - the type of the handled object.

All Implemented Interfaces:

GCUBEIHandler<HANDLED>

Direct Known Subclasses:

GCUBEComplexHandler, GCUBEHandlerConnector, GCUBEScheduledHandler, GCUBEServiceHandler, GCUBETestProbe, LocalMonitor

public abstract class GCUBEHandler<HANDLED>
extends Object
implements GCUBEIHandler<HANDLED>

A partial implementation of GCUBEIHandler.

In particular, a GCUBEHandler:

• has an automatically generated identity;
• has the unqualified name of its class as its default name;
• implements Lifetime for handlers that manage their own lifetime.
  Note: GCUBEHandler implements Lifetime but does not declare it. Subclasses that commit to invoking those methods should do so. Those that do not make this commitment define handlers that remain permanently in the State.Created state.

Author:

Fabio Simeoni (University of Strathclyde)

Field Summary

Fields

Modifier and Type	Field and Description
protected HANDLED	handled The handled object.
protected GCUBELog	logger Object logger.
protected GCUBEProducer<Topic,Object>	producer Internal event producer.

Constructor Summary

Constructors

Constructor and Description
GCUBEHandler() Creates an instance.
GCUBEHandler(HANDLED handled) Creates an instance with a given handled object.

Method Summary

Methods

Modifier and Type	Method and Description
void	clearBlackboard() Clears the blackboard.
Map<String,Object>	getBlackboard() Returns the blackboard.
HANDLED	getHandled() Returns the handled object.
String	getId() Returns the identifier of the handler.
GCUBELog	getLogger() Returns the logger.
String	getName() Returns the name of the handler, by default, the name of its class.
GCUBEScopeManager	getScopeManager() Returns the scope manager of the handler.
GCUBESecurityManager	getSecurityManager() Returns the security manager of the handler.
State	getState() See Lifetime.getState().
protected <TOPIC extends Topic> void	notify(TOPIC topic, Event<TOPIC,?> e) Notifies all subscribed monitors of an Event about an associated Topic.
abstract void	run() Executes the task implemented by the handler.
void	setBlackboard(Map<String,Object> state) Sets the blackboard.
void	setHandled(HANDLED handled) Sets the handled object.
void	setLogger(GCUBELog logger) Sets the logger.
void	setName(String name) Sets the name of the handler.
void	setScopeManager(GCUBEScopeManager manager) Sets a scope manager for the handler.
void	setSecurityManager(GCUBESecurityManager manager) Sets a security manager for the handler.
void	setState(State state) Sets the state of the handler.
void	subscribe(Monitor monitor, Topic... topics) Subscribes a Monitor to one or more Topics.
void	undo() Reverts the actions of the handler.
void	unsubscribe(Monitor monitor, Topic... topics) Unsubscribes a Monitor from one or more Topics.

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected GCUBELog logger

Object logger.

handled

protected HANDLED handled

The handled object.

producer

protected GCUBEProducer<Topic,Object> producer

Internal event producer.

Constructor Detail

GCUBEHandler

public GCUBEHandler()

Creates an instance.

GCUBEHandler

public GCUBEHandler(HANDLED handled)

Creates an instance with a given handled object.

Parameters:

handled - the handled object.

Method Detail

setLogger

public void setLogger(GCUBELog logger)

Sets the logger.

Specified by:

setLogger in interface GCUBEIHandler<HANDLED>

Parameters:

logger - the logger.

getLogger

public GCUBELog getLogger()

Returns the logger.

Specified by:

getLogger in interface GCUBEIHandler<HANDLED>

Returns:

the logger.

run

public abstract void run()
                  throws Exception

Executes the task implemented by the handler.

Specified by:

run in interface GCUBEIHandler<HANDLED>

Throws:

Exception - if the execution of the task does not complete normally.

getHandled

public HANDLED getHandled()

Returns the handled object.

Specified by:

getHandled in interface GCUBEIHandler<HANDLED>

Returns:

the handled object.

setHandled

public void setHandled(HANDLED handled)

Sets the handled object.

Specified by:

setHandled in interface GCUBEIHandler<HANDLED>

Parameters:

handled - the handled object.

getBlackboard

public Map<String,Object> getBlackboard()

Returns the blackboard.

Specified by:

getBlackboard in interface GCUBEIHandler<HANDLED>

Returns:

the blackboard.

setBlackboard

public void setBlackboard(Map<String,Object> state)

Sets the blackboard.

Specified by:

setBlackboard in interface GCUBEIHandler<HANDLED>

Parameters:

state - the blackboard.

clearBlackboard

public void clearBlackboard()

Clears the blackboard.

Specified by:

clearBlackboard in interface GCUBEIHandler<HANDLED>

getId

public String getId()

Returns the identifier of the handler.

Specified by:

getId in interface GCUBEIHandler<HANDLED>

Returns:

the identifier.

getName

public String getName()

Returns the name of the handler, by default, the name of its class.

Specified by:

getName in interface GCUBEIHandler<HANDLED>

Returns:

the name.

setName

public void setName(String name)

Sets the name of the handler.

Specified by:

setName in interface GCUBEIHandler<HANDLED>

Parameters:

name - the name.

undo

public void undo()

Reverts the actions of the handler. By default, it simply debug-logs the invocation. If required, override as per handler semantics. For robustness, do not assume the invocation occurs after the execution of the handler.

Specified by:

undo in interface GCUBEIHandler<HANDLED>

subscribe

public void subscribe(Monitor monitor,
             Topic... topics)

Subscribes a Monitor to one or more Topics.

Specified by:

subscribe in interface GCUBEIHandler<HANDLED>

Parameters:

monitor - the monitor.

topics - (optional) the topics. If omitted, the monitor is subscribed to Topic.LifetimeTopic.

unsubscribe

public void unsubscribe(Monitor monitor,
               Topic... topics)

Unsubscribes a Monitor from one or more Topics.

Specified by:

unsubscribe in interface GCUBEIHandler<HANDLED>

Parameters:

monitor - the monitor.

topics - (optional) the topics. If omitted, the monitor is subscribed to Topic.LifetimeTopic.

notify

protected <TOPIC extends Topic> void notify(TOPIC topic,
                                Event<TOPIC,?> e)

Notifies all subscribed monitors of an Event about an associated Topic.

Parameters:

(optional) - the topic.

e - the event.

getState

public State getState()

See Lifetime.getState().

setState

public void setState(State state)
              throws IllegalArgumentException,
                     IllegalStateException

Sets the state of the handler.

Parameters:

state - the state.

Throws:

IllegalArgumentException - if the state is null

IllegalStateException - if the handler cannot transition to the state from its current state.

setSecurityManager

public void setSecurityManager(GCUBESecurityManager manager)

Sets a security manager for the handler.

Specified by:

setSecurityManager in interface GCUBEIHandler<HANDLED>

Parameters:

manager - the manager.

setScopeManager

public void setScopeManager(GCUBEScopeManager manager)

Sets a scope manager for the handler.

Specified by:

setScopeManager in interface GCUBEIHandler<HANDLED>

Parameters:

manager - the manager.

getSecurityManager

public GCUBESecurityManager getSecurityManager()

Returns the security manager of the handler.

Specified by:

getSecurityManager in interface GCUBEIHandler<HANDLED>

Returns:

the manager.

getScopeManager

public GCUBEScopeManager getScopeManager()

Returns the scope manager of the handler.

Specified by:

getScopeManager in interface GCUBEIHandler<HANDLED>

Returns:

the manager.