weka.knowledgeflow.steps

Class PairedDataHelper<P>

java.lang.Object

weka.knowledgeflow.steps.PairedDataHelper<P>

All Implemented Interfaces:

java.io.Serializable

public class PairedDataHelper<P>
extends java.lang.Object
implements java.io.Serializable

A helper class that Step implementations can use when processing paired data (e.g. train and test sets). Has the concept of a primary and secondary connection/data type, where the secondary connection/data for a given set number typically needs to be processed using a result generated from the corresponding primary connection/data. This class takes care of ensuring that the secondary connection/data is only processed once the primary has completed. Users of this helper need to provide an implementation of the PairedProcessor inner interface, where the processPrimary() method will be called to process the primary data/connection (and return a result), and processSecondary() called to deal with the secondary connection/data. The result of execution on a particular primary data set number can be retrieved by calling the getIndexedPrimaryResult() method, passing in the set number of the primary result to retrieve.

This class also provides an arbitrary storage mechanism for additional results beyond the primary type of result. It also takes care of invoking processing() and finished() on the client step's StepManager.

     public class MyFunkyStep extends BaseStep
       implements PairedDataHelper.PairedProcessor {
       ...
       protected PairedDataHelper m_helper;
       ...
       public void stepInit() {
         m_helper = new PairedDataHelper(this, this,
         StepManager.[CON_WHATEVER_YOUR_PRIMARY_CONNECTION_IS],
         StepManager.[CON_WHATEVER_YOUR_SECONDARY_CONNECTION_IS]);
 
         ...
       }
 
       public void processIncoming(Data data) throws WekaException {
         // delegate to our helper to handle primary/secondary synchronization
         // issues
         m_helper.process(data);
       }
 
       public MyFunkyMainResult processPrimary(Integer setNum, Integer maxSetNun,
         Data data, PairedDataHelper helper) throws WekaException {
           SomeDataTypeToProcess someData = data.getPrimaryPayload();
 
           MyFunkyMainResult processor = new MyFunkyMainResult();
           // do some processing using MyFunkyMainResult and SomeDataToProcess
           ...
           // output some data to downstream steps if necessary
           ...
 
           return processor;
       }
 
       public void processSecondary(Integer setNum, Integer maxSetNum, Data data,
         PairedDataHelper helper) throws WekaException {
         SomeDataTypeToProcess someData = data.getPrimaryPayload();
 
         // get the MyFunkyMainResult for this set number
         MyFunkyMainResult result = helper.getIndexedPrimaryResult(setNum);
 
         // do some stuff with the result and the secondary data
         ...
         // output some data to downstream steps if necessary
       }
     }
 

Version:

$Revision: $

Author:

Mark Hall (mhall{[at]}pentaho{[dot]}com)

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	PairedDataHelper.PairedProcessor<P> Interface for processors of paired data to implement.

Constructor Summary

Constructors

Constructor and Description
PairedDataHelper(Step owner, PairedDataHelper.PairedProcessor processor, java.lang.String primaryConType, java.lang.String secondaryConType) Constructor

Method Summary

Modifier and Type	Method and Description
void	addIndexedValueToNamedStore(java.lang.String storeName, java.lang.Integer index, java.lang.Object value) Adds a value to a named store with the given index.
void	createNamedIndexedStore(java.lang.String name) Create a indexed store with a given name
P	getIndexedPrimaryResult(int index) Retrieve the primary result corresponding to a given set number
<T> T	getIndexedValueFromNamedStore(java.lang.String storeName, java.lang.Integer index) Gets an indexed value from a named store
boolean	isFinished() Return true if there is no further processing to be done
void	process(Data data) Initiate routing and processing for a particular data object
void	reset() Reset the helper.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PairedDataHelper

public PairedDataHelper(Step owner,
                        PairedDataHelper.PairedProcessor processor,
                        java.lang.String primaryConType,
                        java.lang.String secondaryConType)

Constructor

Parameters:

owner - the owner step

processor - the PairedProcessor implementation

primaryConType - the primary connection type

secondaryConType - the secondary connection type

Method Detail

process

public void process(Data data)
             throws WekaException

Initiate routing and processing for a particular data object

Parameters:

data - the data object to process

Throws:

WekaException - if a problem occurs

getIndexedPrimaryResult

public P getIndexedPrimaryResult(int index)

Retrieve the primary result corresponding to a given set number

Parameters:

index - the set number of the result to get

Returns:

the primary result

reset

public void reset()

Reset the helper. The helper must be reset between runs if it is being re-used (as opposed to a new helper instance being created).

isFinished

public boolean isFinished()

Return true if there is no further processing to be done

Returns:

true if processing is done

createNamedIndexedStore

public void createNamedIndexedStore(java.lang.String name)

Create a indexed store with a given name

Parameters:

name - the name of the store to create

getIndexedValueFromNamedStore

public <T> T getIndexedValueFromNamedStore(java.lang.String storeName,
                                           java.lang.Integer index)

Gets an indexed value from a named store

Type Parameters:

T - the type of the value

Parameters:

storeName - the name of the store to retrieve from

index - the index of the value to get

Returns:

the requested value or null if either the store does not exist or the value does not exist in the store.

addIndexedValueToNamedStore

public void addIndexedValueToNamedStore(java.lang.String storeName,
                                        java.lang.Integer index,
                                        java.lang.Object value)

Adds a value to a named store with the given index. Creates the named store if it doesn't already exist.

Parameters:

storeName - the name of the store to add to

index - the index to associate with the value

value - the value to store