com.pervasive.datarush.ports.model

Class AbstractModelPort<T>

java.lang.Object

com.pervasive.datarush.ports.LogicalPort

com.pervasive.datarush.ports.model.AbstractModelPort<T>

Type Parameters:

T - the type of model.

Direct Known Subclasses:

DoneSignalPort, PMMLPort, SimpleModelPort

public abstract class AbstractModelPort<T>
extends LogicalPort

Common base class for all types of model ports. Client's should generally not need to extend this class; rather they should use one of the predefined subclasses (either SimpleModelPort or PMMLPort).

The term "model" originated in the analytics package because model ports are most commonly used for prediction models (i.e. PMML). Model ports share the following characteristics:

• Models are assumed to be "small". By "small" we mean small enough to fit into memory.
• The framework provides built-in support for building partial models and then reducing to a single model. This happens automatically when a parallel operator outputs a model which feeds into a non-parallel operator; the non-parallel operator must specify a merge-handler. Note that MergeModel is a convenient, re-usable model reducer, parameterized with a merge-handler.
• The framework provides built-in support for replicating a final model to a parallelized operator, a common scenario for parallelized predictors. This happens automatically anytime a model from a non-parallel operator is fed into a parallel operator. In this case, a duplicate copy of the model is replicated to all partitions. Note that in this scenario, parallel partitions within the same JVM will share a copy of the model. (This is an optimization to reduce memory consumption). Thus, care must be taken to ensure that predictors not mutate the model.

It's important to highlight the asymmetry: on a model scatter, we always duplicate the model. On a model gather, we always merge the model. (This is quite different from RecordPort's where gather and scatter operators are symmetric).

Nested Class Summary

Nested classes/interfaces inherited from class com.pervasive.datarush.ports.LogicalPort

LogicalPort.Direction

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractModelPort(LogicalOperator owner, String name, LogicalPort.Direction direction, boolean optional, ModelStorageHandler<T> storageHandler) Subclasses must invoke this constructor

Method Summary

Modifier and Type	Method and Description
abstract LogicalPortFactory<? extends AbstractModelPort<?>>	getFactory() Returns the factory that knows how to create ports of this type
abstract AbstractModelPortMetadata	getMetadata(T model) Returns the metadata associate with the model.
T	getModel(ExecutionContext ctx) Reads the model from this model input port.
Class<T>	getModelClass() Returns the java class of the model
protected ModelStorageHandler<T>	getStorageHandler() Returns the storage handler responsible for persisting the model
void	setMergeHandler(MetadataCalculationContext ctx, ModelMergeHandler<T> mergeHandler) Sets the merge handler for the input port
void	setModel(ExecutionContext ctx, T model) Outputs the model on this model output port.

Methods inherited from class com.pervasive.datarush.ports.LogicalPort

getDirection, getMetadataType, getName, getOwner, isOptional, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractModelPort

protected AbstractModelPort(LogicalOperator owner,
                            String name,
                            LogicalPort.Direction direction,
                            boolean optional,
                            ModelStorageHandler<T> storageHandler)

Subclasses must invoke this constructor

Parameters:

owner - the operator that owns this port

name - the name of the port

direction - the direction, input vs. output

optional - whether the port is optional

storageHandler - a storage handler responsible for persisting the model

Method Detail

getModelClass

public final Class<T> getModelClass()

Returns the java class of the model

Returns:

the java class of the model

getStorageHandler

protected final ModelStorageHandler<T> getStorageHandler()

Returns the storage handler responsible for persisting the model

Returns:

the storage handler responsible for persisting the model

getMetadata

public abstract AbstractModelPortMetadata getMetadata(T model)

Returns the metadata associate with the model. (Given a model, we should always be able to get its metadata.

Parameters:

model - the model object

Returns:

the metadata

getFactory

public abstract LogicalPortFactory<? extends AbstractModelPort<?>> getFactory()

Description copied from class: LogicalPort

Returns the factory that knows how to create ports of this type

Specified by:

getFactory in class LogicalPort

Returns:

the factory that knows how to create ports of this type

setMergeHandler

public final void setMergeHandler(MetadataCalculationContext ctx,
                                  ModelMergeHandler<T> mergeHandler)

Sets the merge handler for the input port

Parameters:

ctx - the metadata context

mergeHandler - the merge handler to use

getModel

public final T getModel(ExecutionContext ctx)

Reads the model from this model input port. This method must be invoked at least once for each model input port (additional invocations will return the same model reference as the first)

Parameters:

ctx - the execution context

Returns:

the model from with this model input port.

setModel

public final void setModel(ExecutionContext ctx,
                           T model)

Outputs the model on this model output port. This method must be invoked exactly once for each model output port.

Parameters:

ctx - the execution context

model - the model