org.pentaho.di.trans.steps.reservoirsampling
Class ReservoirSampling

java.lang.Object
  org.pentaho.di.trans.step.BaseStep
      org.pentaho.di.trans.steps.reservoirsampling.ReservoirSampling

All Implemented Interfaces:

HasLogChannelInterface, LoggingObjectInterface, VariableSpace, StepInterface

public class ReservoirSampling
extends BaseStep
implements StepInterface

Field Summary

Fields inherited from class org.pentaho.di.trans.step.BaseStep

first, linesInput, linesOutput, linesRead, linesRejected, linesSkipped, linesUpdated, linesWritten, terminator, terminator_rows

Constructor Summary

ReservoirSampling(StepMeta stepMeta, StepDataInterface stepDataInterface, int copyNr, TransMeta transMeta, Trans trans)
Creates a new ReservoirSampling instance.

Method Summary

boolean	init(StepMetaInterface smi, StepDataInterface sdi) Initialize the step.
boolean	processRow(StepMetaInterface smi, StepDataInterface sdi) Process an incoming row of data.
void	run() Run is where the action happens!

Methods inherited from class org.pentaho.di.trans.step.BaseStep

addResultFile, addRowListener, addStepListener, batchComplete, buildLog, canProcessOneRow, cleanup, closeQuietly, copyVariablesFrom, decrementLinesRead, decrementLinesWritten, dispatch, dispose, environmentSubstitute, environmentSubstitute, findInputRowSet, findInputRowSet, findOutputRowSet, findOutputRowSet, getBooleanValueOfVariable, getClusterSize, getContainerObjectId, getCopy, getDispatcher, getErrorRowMeta, getErrors, getFilename, getInputRowMeta, getInputRowSets, getLinesInput, getLinesOutput, getLinesRead, getLinesRejected, getLinesSkipped, getLinesUpdated, getLinesWritten, getLogChannel, getLogChannelId, getLogFields, getLogLevel, getNextClassNr, getObjectCopy, getObjectId, getObjectName, getObjectRevision, getObjectType, getOutputRowSets, getParent, getParentVariableSpace, getPartitionID, getPartitionTargets, getPreviewRowMeta, getProcessed, getRegistrationDate, getRemoteInputSteps, getRemoteOutputSteps, getRepartitioning, getRepositoryDirectory, getResultFiles, getRow, getRowFrom, getRowListeners, getRuntime, getServerSockets, getSlaveNr, getSocketRepository, getStatus, getStatusDescription, getStepDataInterface, getStepID, getStepListeners, getStepMeta, getStepMetaInterface, getStepname, getTrans, getTransMeta, getTypeId, getUniqueStepCountAcrossSlaves, getUniqueStepNrAcrossSlaves, getVariable, getVariable, identifyErrorOutput, incrementLinesInput, incrementLinesOutput, incrementLinesRead, incrementLinesRejected, incrementLinesSkipped, incrementLinesUpdated, incrementLinesWritten, initBeforeStart, initializeVariablesFrom, injectVariables, isBasic, isDebug, isDetailed, isDistributed, isInitialising, isMapping, isPartitioned, isPaused, isRowLevel, isRunning, isStopped, isUsingThreadPriorityManagment, listVariables, logBasic, logBasic, logDebug, logDebug, logDetailed, logDetailed, logError, logError, logError, logMinimal, logMinimal, logRowlevel, logRowlevel, logSummary, markStart, markStop, outputIsDone, pauseRunning, putError, putRow, putRowTo, removeRowListener, resumeRunning, rowsetInputSize, rowsetOutputSize, safeModeChecking, setCarteObjectId, setCopy, setDistributed, setErrorRowMeta, setErrors, setInputRowMeta, setInputRowSets, setInternalVariables, setLinesInput, setLinesOutput, setLinesRead, setLinesRejected, setLinesSkipped, setLinesUpdated, setLinesWritten, setLogLevel, setOutputDone, setOutputRowSets, setParentVariableSpace, setPartitioned, setPartitionID, setPartitionTargets, setPaused, setPaused, setPreviewRowMeta, setRepartitioning, setRunning, setServerSockets, setSocketRepository, setStepDataInterface, setStepListeners, setStepMeta, setStepMetaInterface, setStepname, setStopped, setTransMeta, setUsingThreadPriorityManagment, setVariable, shareVariablesWith, stopAll, stopRunning, stopRunning, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.pentaho.di.trans.step.StepInterface

addRowListener, addStepListener, batchComplete, canProcessOneRow, cleanup, dispose, getCopy, getErrors, getInputRowSets, getLinesInput, getLinesOutput, getLinesRead, getLinesRejected, getLinesUpdated, getLinesWritten, getLogChannel, getOutputRowSets, getPartitionID, getProcessed, getResultFiles, getRow, getRowListeners, getRuntime, getStatus, getStepID, getStepMeta, getStepname, getTrans, identifyErrorOutput, initBeforeStart, isMapping, isPartitioned, isPaused, isRunning, isStopped, isUsingThreadPriorityManagment, markStart, markStop, pauseRunning, putRow, removeRowListener, resumeRunning, rowsetInputSize, rowsetOutputSize, setErrors, setLinesRejected, setOutputDone, setPartitioned, setPartitionID, setRepartitioning, setRunning, setStopped, setUsingThreadPriorityManagment, stopAll, stopRunning

Methods inherited from interface org.pentaho.di.core.variables.VariableSpace

copyVariablesFrom, environmentSubstitute, environmentSubstitute, getBooleanValueOfVariable, getParentVariableSpace, getVariable, getVariable, initializeVariablesFrom, injectVariables, listVariables, setParentVariableSpace, setVariable, shareVariablesWith

Constructor Detail

ReservoirSampling

public ReservoirSampling(StepMeta stepMeta,
                         StepDataInterface stepDataInterface,
                         int copyNr,
                         TransMeta transMeta,
                         Trans trans)

Creates a new ReservoirSampling instance.

Implements the reservoir sampling algorithm "R" by Jeffrey Scott Vitter. (algorithm is implemented in ReservoirSamplingData.java

For more information see:

Vitter, J. S. Random Sampling with a Reservoir. ACM Transactions on Mathematical Software, Vol. 11, No. 1, March 1985. Pages 37-57.

Parameters:

stepMeta - holds the step's meta data

stepDataInterface - holds the step's temporary data

copyNr - the number assigned to the step

transMeta - meta data for the transformation

trans - a Trans value

Method Detail

processRow

public boolean processRow(StepMetaInterface smi,
                          StepDataInterface sdi)
                   throws KettleException

Process an incoming row of data.

Specified by:

processRow in interface StepInterface

Overrides:

processRow in class BaseStep

Parameters:

smi - a StepMetaInterface value

sdi - a StepDataInterface value

Returns:

a boolean value

Throws:

KettleException - if an error occurs

init

public boolean init(StepMetaInterface smi,
                    StepDataInterface sdi)

Initialize the step.

Specified by:

init in interface StepInterface

Overrides:

init in class BaseStep

Parameters:

smi - a StepMetaInterface value

sdi - a StepDataInterface value

Returns:

a boolean value

run

public void run()

Run is where the action happens!