uk.org.ogsadai.activity.transform
Class CSVProjectionActivity

java.lang.Object
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  +--uk.org.ogsadai.activity.Activity
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        +--uk.org.ogsadai.activity.transform.CSVProjectionActivity

public class CSVProjectionActivity

extends Activity

A CSVProjectionActivity projects the i-th value from a sequence of CSV values. The delimeter of the CSV values can be any single character except double quotes (").The input is tokenized according to the delimeter parameter. If double quotes are part of a token, then they should be represented as a pair of double quotes (""). Finally, the projection is based on the index specifying the column to be projected.

A short example to illustrate the functionality of this activity is as follows:

If the CSV values are 1,3,5 and the second value has to be projected, then the output of the activity will be the value 3.

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

Author:

The OGSA-DAI Project Team

Field Summary

private int	columnNo which column to be projected
private static java.lang.String	COPYRIGHT_NOTICE Copyright
private java.lang.String	delim the delimeter of the seqeunce of values.
private BlockReader	mInput Activity input.
private BlockWriter	mOutput Activity output.

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

mContext, mExternalInputs, mExternalOutputs, mInternalInputs, mInternalOutputs

Constructor Summary

CSVProjectionActivity(org.w3c.dom.Element element)

Method Summary

private java.lang.String	findValue(java.lang.String input)
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

See Also:

Constant Field Values

mInput

private BlockReader mInput

Activity input.

mOutput

private BlockWriter mOutput

Activity output.

columnNo

private int columnNo

which column to be projected

delim

private java.lang.String delim

the delimeter of the seqeunce of values. The default is the comma (;)

Constructor Detail

CSVProjectionActivity

public CSVProjectionActivity(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

findValue

private java.lang.String findValue(java.lang.String input)
                            throws ActivitySpecificationException

ActivitySpecificationException