ibis.constellation.util

Class MultiEventCollector

java.lang.Object

ibis.constellation.Activity

ibis.constellation.util.MultiEventCollector

All Implemented Interfaces:

java.io.Serializable

public class MultiEventCollector
extends Activity

A MultiEventCollector is an Activity that just waits for a specific number of events, and collects them. It provides a method waitForEvents(), to be used by other activities, to collect the events and block until the specified number of events is reached, after which the MultiEventCollector 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
MultiEventCollector(AbstractContext c, int events) Constructs a MultiEventCollector with the specified activity context and event count.

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[]	waitForEvents() This method blocks waiting for the specified number of events.

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

MultiEventCollector

public MultiEventCollector(AbstractContext c,
                           int events)

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

Parameters:

c - the activity context of this event collector

events - the number of events to be collected

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

waitForEvents

public Event[] waitForEvents()

This method blocks waiting for the specified number of events. As soon as they are available, it creates an array containing these events, and returns the array.

Returns:

an array containing the received events.

isFinished

public boolean isFinished()

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

Returns:

whether the event collector is finished.