org.gcube.common.core.utils.handlers
Class GCUBESequentialHandler<HANDLED>

java.lang.Object
  org.gcube.common.core.utils.handlers.GCUBEHandler<HANDLED>
      org.gcube.common.core.utils.handlers.GCUBEComplexHandler<HANDLED>
          org.gcube.common.core.utils.handlers.GCUBESequentialHandler<HANDLED>

Type Parameters:

HANDLED - the type of the object handled by the component handlers.

All Implemented Interfaces:

GCUBEIHandler<HANDLED>, Lifetime<HANDLED>

public class GCUBESequentialHandler<HANDLED>
extends GCUBEComplexHandler<HANDLED>
implements Lifetime<HANDLED>

An extension of GCUBEComplexHandler for handlers which chain the execution of their component handlers. A GCUBESequentialHandler propagates its state across the chain as a blackboard based on which component handlers may may communicate in a decoupled fashion. For further decoupling, a GCUBESequentialHandler recognises components which have the semantics of GCUBEHandlerConnectors and connects them to components which immediately precede them and immediately follow them in the chain.

Author:

Fabio Simeoni (University of Strathclyde)

See Also:

GCUBEHandlerConnector

Field Summary

Fields inherited from class org.gcube.common.core.utils.handlers.GCUBEHandler

handled, logger, producer

Constructor Summary

GCUBESequentialHandler(GCUBEIHandler<? extends HANDLED>... components)
Creates an instance with a list of component handlers.

Method Summary

protected List<GCUBEIHandler<? extends HANDLED>>	connectComponents() Invoked internally before a run to insert and configure GCUBEHandlerConnectors before running.
void	run() Executes the task implemented by the handler.

Methods inherited from class org.gcube.common.core.utils.handlers.GCUBEComplexHandler

addHandlers, getHandlers, removeHandler, setLogger, undo

Methods inherited from class org.gcube.common.core.utils.handlers.GCUBEHandler

clearBlackboard, getBlackboard, getHandled, getId, getLogger, getName, getScopeManager, getSecurityManager, getState, notify, setBlackboard, setHandled, setName, setScopeManager, setSecurityManager, setState, subscribe, unsubscribe

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.gcube.common.core.utils.handlers.lifetime.Lifetime

getState

Methods inherited from interface org.gcube.common.core.utils.handlers.GCUBEIHandler

clearBlackboard, getBlackboard, getHandled, getId, getLogger, getName, getScopeManager, getSecurityManager, setBlackboard, setHandled, setLogger, setName, setScopeManager, setSecurityManager, subscribe, undo, unsubscribe

Constructor Detail

GCUBESequentialHandler

public GCUBESequentialHandler(GCUBEIHandler<? extends HANDLED>... components)

Creates an instance with a list of component handlers.

Parameters:

components - the component handlers.

Method Detail

run

public void run()
         throws Exception

Executes the task implemented by the handler.

Specified by:

run in interface GCUBEIHandler<HANDLED>

Specified by:

run in class GCUBEHandler<HANDLED>

Throws:

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

connectComponents

protected List<GCUBEIHandler<? extends HANDLED>> connectComponents()

Invoked internally before a run to insert and configure GCUBEHandlerConnectors before running. In particular, existing connectors are configured and new GCUBEHandlerConnectors are inserted in between non-connector components.

Returns:

the list of component handlers augmented with configured connectors.