uk.org.ogsadai.activity.misc
Class NotificationActivity

java.lang.Object
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  +--uk.org.ogsadai.activity.Activity
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        +--uk.org.ogsadai.activity.misc.NotificationActivity

public class NotificationActivity

extends Activity

An activity that produces a notification message when the output stream of another activity has completed or commenced.

The activity pipes data in, through and out without changing it. The activity uses a second output stream for the notifications.

For information on this activity see the OGSA-DAI user doc: OGSA-DAI/doc/interaction/activities/relational/notification.html

Author:

The OGSA-DAI Project Team

Field Summary

private static int	COMMENCED Notification type - notify when activity commences
private static int	COMPLETE Notification type - notify when activity completes
private static java.lang.String	COPYRIGHT_NOTICE Copyright statement
private static DAILogger	LOG Logger object for logging in this class
private BlockReader	mDataInput Input stream
private BlockWriter	mDataOutput Data output stream
private java.lang.String	mMessage Notification message
private BlockWriter	mNotificationOutput Notification message output stream
private int	mNotifyType Current notification type
private static int	NONE Notification type - none

Fields inherited from class uk.org.ogsadai.activity.Activity

mContext, mExternalInputs, mExternalOutputs, mInternalInputs, mInternalOutputs

Constructor Summary

NotificationActivity(org.w3c.dom.Element element)
Constructs an activity using the specified element.

Method Summary

void	initialise() This method should be overridden by subclasses to perform any initialisation they require before the process method invocations begin.
void	processBlock() Performs an iteration of the processing of an activity.
void	processFirst() This method is called during the first iteration of processing an activity.

Methods inherited from class uk.org.ogsadai.activity.Activity

cleanUp, connectsTo, createOutputPipe, getActivityConfiguration, getActivityName, getCause, getName, getObservableStatus, getProperties, getSession, getStatus, hasActivityConfiguration, hasProperties, process, setActivityName, setCompleted, setError

Methods inherited from class java.lang.Object

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

Field Detail

COPYRIGHT_NOTICE

private static final java.lang.String COPYRIGHT_NOTICE

Copyright statement

See Also:

Constant Field Values

LOG

private static DAILogger LOG

Logger object for logging in this class

NONE

private static final int NONE

Notification type - none

See Also:

Constant Field Values

COMMENCED

private static final int COMMENCED

Notification type - notify when activity commences

See Also:

Constant Field Values

COMPLETE

private static final int COMPLETE

Notification type - notify when activity completes

See Also:

Constant Field Values

mNotifyType

private int mNotifyType

Current notification type

mMessage

private java.lang.String mMessage

Notification message

mDataInput

private BlockReader mDataInput

Input stream

mDataOutput

private BlockWriter mDataOutput

Data output stream

mNotificationOutput

private BlockWriter mNotificationOutput

Notification message output stream

Constructor Detail

NotificationActivity

public NotificationActivity(org.w3c.dom.Element element)
                     throws ActivitySpecificationException,
                            ActivityCreationException

Constructs an activity using the specified element.

Parameters:

element - Element to configure the activity with - from a perform document.

Throws:

ActivityCreationException - If there is a problem constructing the activity.

ActivitySpecificationException - If there is a problem constructing the activity due to an invalid setting in element.

See Also:

uk.org.ogsadai.activity

Method Detail

initialise

public void initialise()
                throws ActivitySpecificationException,
                       ActivityExecutionException

Description copied from class: Activity

This method should be overridden by subclasses to perform any initialisation they require before the process method invocations begin. This might be used for setting up convenient fields to reference objects contained in the context. It shouldn't be used for opening resources. That should be done in processFirst.

Overrides:

initialise in class Activity

Throws:

ActivityExecutionException - If some system problem prevents the activity from initialising.

ActivitySpecificationException - If a problem with settings provided by a client prevents the activity from initialising.

processFirst

public void processFirst()

Description copied from class: Activity

This method is called during the first iteration of processing an activity. It can be overridden by subclasses to define some processing that should be done only once during the first iteration of the activity processing, for example evaluating a database query.

Overrides:

processFirst in class Activity

processBlock

public void processBlock()

Description copied from class: Activity

Performs an iteration of the processing of an activity. This may involve reading a block of input data and writing a block of output data, or may involve some other kind of processing. When an activity is processed by the OGSA-DAI engine, this method will be invoked repeatedly until the activity either completes or stops due to an error or termination call. An implementation of this method should invoke the setCompleted method to indicate that processing is complete, or the setError method if an error occurs that will prevent the processing from completing.

Specified by:

processBlock in class Activity