ibis.constellation.util

Class SingleEventCollector

java.lang.Object

ibis.constellation.Activity

ibis.constellation.util.SingleEventCollector

All Implemented Interfaces:

java.io.Serializable

public class SingleEventCollector
extends Activity

A SingleEventCollector is an Activity that just waits for a single event, and saves it. It provides a method waitForEvent(), to be used by other activities, to collect the event and block until it arrives, after which the SingleEventCollector will finish.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static org.slf4j.Logger	logger

Fields inherited from class ibis.constellation.Activity

FINISH, SUSPEND

Constructor Summary

Constructors

Constructor and Description
SingleEventCollector(AbstractContext c) Constructs a SingleEventCollector with the specified activity context.

Method Summary

Modifier and Type	Method and Description
void	cleanup(Constellation c) The implementation of this method is called when the activity is finished.
int	initialize(Constellation c) The implementation of this method should perform the initial processing when the activity is first activated.
boolean	isFinished() This method returns whether the event collector is finished, without blocking.
int	process(Constellation c, Event e) The implementation of this method is called when an event is received for this activity.
java.lang.String	toString()
Event	waitForEvent() This method blocks waiting for this object to receive an event.

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, wait, wait, wait

Field Detail

logger

public static final org.slf4j.Logger logger

Constructor Detail

SingleEventCollector

public SingleEventCollector(AbstractContext c)

Constructs a SingleEventCollector with the specified activity context. Note: this is an activity that will receive events (see Activity.Activity(AbstractContext, boolean)).

Parameters:

c - the activity context of this event collector

Method Detail

initialize

public int initialize(Constellation c)

Description copied from class: Activity

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.

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 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 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

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

waitForEvent

public Event waitForEvent()

This method blocks waiting for this object to receive an event. As soon as it is available, it returns the event.

Returns:

the received event.

isFinished

public boolean isFinished()

This method returns whether the event collector is finished, without blocking.

Returns:

whether the event collector is finished.