uk.org.ogsadai.activity.transform
Class FrequencyDistributorActivity

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

public class FrequencyDistributorActivity

extends Activity

A FrequencyDistributorActivity distributes the input values, that should be numeric, into the corresponding spaces that emerge from the parameter sequence of values.

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

Let us say that the parameter sequence of values is 1,5 and the input numerical values are 0,2,3,7. The spaces that emerge are: (-inf,1], (1,5], (5,+inf). There is one value lying in the first space (0), two values lying in the second space (2,3) and one value lying in the third space (7). Therefore, the output will be these values representing the distribution in each space, i.e. 1,2,1.

This functionality is similar to the principles of histograms.

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

Author:

The OGSA-DAI Project Team

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.

mAttributeSequence

private int[] mAttributeSequence

Values that define the spaces

mDistributionArray

private int[] mDistributionArray

Distribution array containing the output values

FrequencyDistributorActivity

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

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

findSpace

private int findSpace(int[] array,
                      int target)

Method to find in which space the input value belongs to.

Parameters:

array - Input spaces

target - Input value