Package nz.org.riskscape.engine.pipeline

Class NullStep

java.lang.Object

nz.org.riskscape.engine.pipeline.NullStep

All Implemented Interfaces:

Identified, Step

public class NullStep
extends Object
implements Step

A Pipeline Step that does nothing. It is mostly here for completeness and is useful in cases where a null might want to be returned or where something needs to be present that isn't an actual useful thing. If realized, this step produces an empty relation that yields an empty struct.

TODO We may want to tweak it slightly so that if given input it yields a Restrictor that always says no.

Field Summary

Fields

Modifier and Type	Field	Description
static final NullStep	INSTANCE

Fields inherited from interface nz.org.riskscape.engine.pipeline.Step

FUNCTOR_INTERFACES

Constructor Summary

Constructors

Constructor	Description
NullStep()

Method Summary

Modifier and Type	Method	Description
RiskscapeMessage	getDescription()
String	getId()
com.google.common.collect.Range<Integer>	getInputArity()
ParameterSet	getParameterSet()	The set of Parameters this step accepts.
RealizedPipeline	realize(RealizationInput input)	Produce a new pipeline that is the result of realizing this step against the input.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface nz.org.riskscape.engine.Identified

getIdentifiedClass

Methods inherited from interface nz.org.riskscape.engine.pipeline.Step

getDeclaredParameter, getDeclaredParameterNames, getDeclaredParameters, getDefaultInputName, getInputNames, hasNamedInput

Field Details

INSTANCE

public static final NullStep INSTANCE

Constructor Details

NullStep

public NullStep()

Method Details

getParameterSet

public ParameterSet getParameterSet()

Description copied from interface: Step

The set of Parameters this step accepts. These should be used to populate a map for the Step.realize(RealizationInput) method

Specified by:

getParameterSet in interface Step

getInputArity

public com.google.common.collect.Range<Integer> getInputArity()

Specified by:

getInputArity in interface Step

Returns:

a range that describes the number of inputs this step supports. NB a bit unsure whether we really need this - at the moment it's defined by the functor... but it's possible we might need a n-input join functor...

realize

public RealizedPipeline realize(RealizationInput input)

Description copied from interface: Step

Produce a new pipeline that is the result of realizing this step against the input.

Specified by:

realize in interface Step

Parameters:

input - the 'payload' for realization.

getId

public String getId()

Specified by:

getId in interface Identified

Returns:

id

getDescription

public RiskscapeMessage getDescription()

Specified by:

getDescription in interface Step

Returns:

A human digestible description for this step.

toString

public String toString()

Overrides:

toString in class Object