ibis.constellation.util

Class SimpleActivity

java.lang.Object

ibis.constellation.Activity

ibis.constellation.util.SimpleActivity

All Implemented Interfaces:

java.io.Serializable

public abstract class SimpleActivity
extends Activity

A SimpleActivity is an activity that only requires a single invocation of its simpleActivity(ibis.constellation.Constellation) method. In particular, it has (default) implementations of Activity.initialize(ibis.constellation.Constellation) and Activity.cleanup(ibis.constellation.Constellation), and it does not expect events. It does provide a concept of a parent activity.

See Also:

Serialized Form

Field Summary

Fields inherited from class ibis.constellation.Activity

FINISH, SUSPEND

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	SimpleActivity(ActivityIdentifier parent, AbstractContext context) Constructs a SimpleActivity with the specified parameters.
protected	SimpleActivity(ActivityIdentifier parent, AbstractContext context, boolean mayBeStolen) Constructs a SimpleActivity with the specified parameters.

Method Summary

Modifier and Type	Method and Description
void	cleanup(Constellation c) The implementation of this method is called when the activity is finished.
ActivityIdentifier	getParent() Returns the activity identifier of the parent (as set in the constructor), so it may be null).
int	initialize(Constellation c) The implementation of this method should perform the initial processing when the activity is first activated.
int	process(Constellation c, Event e) The implementation of this method is called when an event is received for this activity.
abstract void	simpleActivity(Constellation c) This method, to be implemented by the activity, is called once, after which the activity will finish.

Methods inherited from class ibis.constellation.Activity

expectsEvents, getContext, identifier, mayBeStolen, setIdentifier

Methods inherited from class java.lang.Object

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

Constructor Detail

SimpleActivity

protected SimpleActivity(ActivityIdentifier parent,
                         AbstractContext context)

Constructs a SimpleActivity with the specified parameters. This activity can only be executed by a local executor.

Parameters:

parent - the activity identifier of the parent activity (may be null).

context - the context that specifies which executors can actually execute this activity.

SimpleActivity

protected SimpleActivity(ActivityIdentifier parent,
                         AbstractContext context,
                         boolean mayBeStolen)

Constructs a SimpleActivity with the specified parameters.

Parameters:

parent - the activity identifier of the parent activity (may be null).

context - the context that specifies which executors can actually execute this activity.

mayBeStolen - when set, this activity may be stolen by other Constellations.

Method Detail

initialize

public int initialize(Constellation c)

The implementation of this method should perform the initial processing when the activity is first activated. It may perform as much processing as needed, but should not block for a prolonged period, as this may result in deadlocks. When finished, it should return either Activity.SUSPEND or Activity.FINISH, depending on what the activity is to do next: Activity.SUSPEND when it wants to wait for events, and Activity.FINISH when it is done. Note that this method does not throw checked exceptions. It can, however, throw runtime exceptions or errors, and the Constellation running this Activity will deal with that. This version of Activity.initialize(ibis.constellation.Constellation) calls simpleActivity(ibis.constellation.Constellation) and returns Activity.FINISH.

Specified by:

initialize in class Activity

Parameters:

c - the Constellation on which the Activity is running

Returns:

either FINISH if this Activity is done or SUSPEND if this Activity expects events.

process

public final int process(Constellation c,
                         Event e)

Description copied from class: Activity

The implementation of this method is called when an event is received for this activity. After the event is processed it must return Activity.SUSPEND or Activity.FINISH, depending on what the activity is to do next: Activity.SUSPEND when it expects other events, and Activity.FINISH when it is done. This method is invoked once at a time, even if more events arrive more or less simultaneously. Note that this method does not throw checked exceptions. It can, however, throw runtime exceptions or errors, and the Constellation running this Activity will deal with that.

Specified by:

process in class Activity

Parameters:

c - the Constellation on which the Activity is running

e - the Event to process.

Returns:

either FINISH if this Activity is done or SUSPEND if this Activity expects events.

cleanup

public final void cleanup(Constellation c)

Description copied from class: Activity

The implementation of this method is called when the activity is finished. It allows the activity to perform cleanup, and, for example, send events to its parent activity. Note that this method does not throw checked exceptions. It can, however, throw runtime exceptions or errors, and the Constellation running this Activity will deal with that.

Specified by:

cleanup in class Activity

Parameters:

c - the Constellation on which the Activity is running

simpleActivity

public abstract void simpleActivity(Constellation c)

This method, to be implemented by the activity, is called once, after which the activity will finish.

Parameters:

c - the Constellation on which the Activity is running

getParent

public ActivityIdentifier getParent()

Returns the activity identifier of the parent (as set in the constructor), so it may be null).

Returns:

the parent activity identifier