uk.org.ogsadai.activity.examples
Class DemoExternalInputActivity

java.lang.Object
  |
  +--uk.org.ogsadai.activity.Activity
        |
        +--uk.org.ogsadai.activity.examples.DemoExternalInputActivity

public class DemoExternalInputActivity

extends Activity

Activity to demonstrate the external input functionality. This allows an activity to create an input stream that is not specified in the perform document. Clients may then write data to this input stream.

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

Author:

The OGSA-DAI Project Team

Field Summary

private static java.lang.String	COPYRIGHT_NOTICE Copyright statement
private static DAILogger	LOG Logger object for this activity
private BlockReader	mInput External input
private int	mNumInputBlocks Number of expected input blocks.
private BlockWriter	mOutput Activity output.
private java.lang.String	mStreamName Stream name for input.

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

mContext, mExternalInputs, mExternalOutputs, mInternalInputs, mInternalOutputs

Constructor Summary

DemoExternalInputActivity(org.w3c.dom.Element 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.

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

cleanUp, connectsTo, createOutputPipe, getActivityConfiguration, getActivityName, getCause, getName, getObservableStatus, getProperties, getSession, getStatus, hasActivityConfiguration, hasProperties, process, processFirst, 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 final DAILogger LOG

Logger object for this activity

mInput

private BlockReader mInput

External input

mOutput

private BlockWriter mOutput

Activity output.

mNumInputBlocks

private int mNumInputBlocks

Number of expected input blocks.

mStreamName

private java.lang.String mStreamName

Stream name for input.

Constructor Detail

DemoExternalInputActivity

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

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.

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