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uk.org.ogsadai.activity.delivery
Class OutputStreamActivity

java.lang.Object
  |
  +--uk.org.ogsadai.activity.Activity
        |
        +--uk.org.ogsadai.activity.delivery.OutputStreamActivity
public class OutputStreamActivity
extends Activity

Create an output stream that is exposed via a service's data transport getFully/NBlocks/Block operations.

For information on this activity see the OGSA-DAI user doc: OGSA-DAI/doc/interaction/activities/delivery/outputStream.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.
private  BlockReader mInput
          Activity input - output from another activity
private  BlockWriter mOutput
          Activity output - exposed to client via data transport operations
 
Fields inherited from class uk.org.ogsadai.activity.Activity
mContext, mExternalInputs, mExternalOutputs, mInternalInputs, mInternalOutputs
 
Constructor Summary
OutputStreamActivity(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 DAILogger LOG
Logger object for logging in this class.

mInput

private BlockReader mInput
Activity input - output from another activity

mOutput

private BlockWriter mOutput
Activity output - exposed to client via data transport operations

Constructor Detail

OutputStreamActivity

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