uk.org.ogsadai.activity.delivery
Class AbstractDTDeliveryActivity

java.lang.Object
  |
  +--uk.org.ogsadai.activity.Activity
        |
        +--uk.org.ogsadai.activity.delivery.AbstractDTDeliveryActivity

Direct Known Subclasses:

AbstractDeliverFromDTActivity, AbstractDeliverToDTActivity

public abstract class AbstractDTDeliveryActivity

extends Activity

This class is an abstract super-class of activities supporting invocation of data transport operations on data services.

For information on this activity see the OGSA-DAI user doc: OGSA-DAI/doc/interaction/activities/delivery/deliverToGDT.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 logging in this class.
protected boolean	mBlockMode Is transfer mode block (true) or full (false)?
protected org.w3c.dom.Node	mDeliveryNode Node containing target service-related delivery information
protected java.lang.String	mLocalStream Name of local stream
protected java.lang.String	mResourceID ID of data service resource exposed by the target service
protected java.lang.String	mServiceType Type of service - "wsi", "wsrf", "unknown"
protected java.lang.String	mServiceURL URL of target service
protected java.lang.String	mStreamID ID of stream exposed by the data service resource

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

mContext, mExternalInputs, mExternalOutputs, mInternalInputs, mInternalOutputs

Constructor Summary

AbstractDTDeliveryActivity(org.w3c.dom.Element element)

Method Summary

protected abstract void	contactTargetService() Create a stub for the target service.
protected void	getDeliverySettings(org.w3c.dom.Element activity, java.lang.String targetNode, java.lang.String localStreamNode, java.lang.String localStreamAttr) Gets the settings for the delivery.
void	initialise() This method should be overridden by subclasses to perform any initialisation they require before the process method invocations begin.
protected boolean	isServiceUnknown() Return flag indicating that it is unknown whether the target service is an OGSA-DAI WSI or OGSA-DAI WSRF service.
protected boolean	isServiceWSI() Return flag indicating whether client has stated that target service is an OGSA-DAI WSI service.
protected boolean	isServiceWSRF() Return flag indicating whether client has stated that target service is an OGSA-DAI WSRF service.
protected abstract void	processBlock() Performs an iteration of the processing of an activity.
protected 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 final DAILogger LOG

Logger object for logging in this class.

mServiceURL

protected java.lang.String mServiceURL

URL of target service

mResourceID

protected java.lang.String mResourceID

ID of data service resource exposed by the target service

mStreamID

protected java.lang.String mStreamID

ID of stream exposed by the data service resource

mBlockMode

protected boolean mBlockMode

Is transfer mode block (true) or full (false)?

mLocalStream

protected java.lang.String mLocalStream

Name of local stream

mDeliveryNode

protected org.w3c.dom.Node mDeliveryNode

Node containing target service-related delivery information

mServiceType

protected java.lang.String mServiceType

Type of service - "wsi", "wsrf", "unknown"

Constructor Detail

AbstractDTDeliveryActivity

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

Method Detail

processBlock

protected abstract 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

getDeliverySettings

protected void getDeliverySettings(org.w3c.dom.Element activity,
                                   java.lang.String targetNode,
                                   java.lang.String localStreamNode,
                                   java.lang.String localStreamAttr)

Gets the settings for the delivery.

This includes the URL of the target data service, the ID of a data service resource exposed by the target service, the ID of a session and stream exposed by the data service resource and the data transport mode. In addition to the local activity stream that will provide or receive data. Activity-specific information relating to the target service is extracted as DOM nodes but are not processed.

Parameters:

activity - Activity element from request.

targetNode - Name of element containing target data service information.

localStreamNode - Name of element containing local activity stream name.

localStreamAttr - Name of attribute of localStreamNode containing local activity stream name.

isServiceWSRF

protected boolean isServiceWSRF()

Return flag indicating whether client has stated that target service is an OGSA-DAI WSRF service.

Returns:

true if so, false otherwise.

isServiceWSI

protected boolean isServiceWSI()

Return flag indicating whether client has stated that target service is an OGSA-DAI WSI service.

Returns:

true if so, false otherwise.

isServiceUnknown

protected boolean isServiceUnknown()

Return flag indicating that it is unknown whether the target service is an OGSA-DAI WSI or OGSA-DAI WSRF service.

Returns:

true if unknown, false otherwise.

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

protected 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

contactTargetService

protected abstract void contactTargetService()
                                      throws ActivitySpecificationException,
                                             ActivityExecutionException

Create a stub for the target service.

Throws:

ActivitySpecificationException - If an error occurs that is caused by incorrect information in the request e.g. the URL is incorrect or cannot be contacted.

ActivityExecutionException - If some internal problem outwith the client's control occurs.