uk.org.ogsadai.activity.transform
Class StringTokenizerActivity

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

public class StringTokenizerActivity

extends Activity

This activity tokenizes the input data it recieves using a specified set of delimiters. The functionality is similar to that provided by the java.util.StringTokenizer class. This class has one input (the blocks of data to be tokenized) and one output (the tokens). This activity supports any type of input data, but blocks which are not instances of String or byte[] will be converted into strings using their toString methods. For information on this activity see the OGSA-DAI user doc: OGSA-DAI/doc/interaction/activities/transform/stringTokenizer.html

Author:

The OGSA-DAI Project Team

Field Summary

private static java.lang.String	COPYRIGHT_NOTICE Copyright notice
private java.lang.String	mDelimiters String containing the delimiter(s) used for tokenizing.
private BlockReader	mInput Input string data.
private BlockWriter	mOutput Tokenized output data.
private java.util.StringTokenizer	mTokenizer Used for tokenizing the input data.

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

mContext, mExternalInputs, mExternalOutputs, mInternalInputs, mInternalOutputs

Constructor Summary

StringTokenizerActivity(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.
private void	maintainTokenizer() This method maintains the mTokenizer field by making sure that it is initialised with the next block of input data whenever it runs out of tokens.
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 notice

See Also:

Constant Field Values

mInput

private BlockReader mInput

Input string data.

mOutput

private BlockWriter mOutput

Tokenized output data.

mDelimiters

private java.lang.String mDelimiters

String containing the delimiter(s) used for tokenizing.

mTokenizer

private java.util.StringTokenizer mTokenizer

Used for tokenizing the input data.

Constructor Detail

StringTokenizerActivity

public StringTokenizerActivity(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

maintainTokenizer

private final void maintainTokenizer()

This method maintains the mTokenizer field by making sure that it is initialised with the next block of input data whenever it runs out of tokens.