org.jpmml.evaluator

Interface Evaluator

All Superinterfaces:

HasActiveFields, HasInputFields, HasResultFields

All Known Implementing Classes:

AssociationModelEvaluator, ClusteringModelEvaluator, ComplexTreeModelEvaluator, GeneralRegressionModelEvaluator, JavaModelEvaluator, MiningModelEvaluator, ModelEvaluator, NaiveBayesModelEvaluator, NearestNeighborModelEvaluator, NeuralNetworkEvaluator, RegressionModelEvaluator, RuleSetModelEvaluator, ScorecardEvaluator, SimpleTreeModelEvaluator, SupportVectorMachineModelEvaluator, TreeModelEvaluator

public interface Evaluator
extends HasInputFields, HasResultFields

Performs the evaluation of a Model.

Building and verifying an Evaluator instance

 PMML pmml = ...;
 EvaluatorBuilder evaluatorBuilder = new ModelEvaluatorBuilder(pmml);
 Evaluator evaluator = evaluatorBuilder.build();
 evaluator.verify();
 

Preparing arguments

Transforming an user-supplied map of arguments to a known-good PMML map of arguments:

 Map<String, ?> userArguments = ...;
 Map<FieldName, FieldValue> arguments = new LinkedHashMap<>();
 List<? extends InputField> inputFields = evaluator.getInputFields();
 for(InputField inputField : inputFields){
   FieldName inputName = inputField.getName();
   Object rawValue = userArguments.get(inputName.getValue());
   FieldValue inputValue = inputField.prepare(rawValue);
   arguments.put(inputName, inputValue);
 }
 

Performing the evaluation

 Map<FieldName, ?> results = evaluator.evaluate(arguments);
 

Processing results

Retrieving the values of target fields (ie. primary results):

 List<? extends TargetField> targetFields = evaluator.getTargetFields();
 for(TargetField targetField : targetFields){
   FieldName targetName = targetField.getName();
   Object targetValue = results.get(targetName);
 }
 

Decoding a complex value to a Java primitive value:

 if(targetValue instanceof Computable){
   Computable computable = (Computable)targetValue;
   targetValue = computable.getResult();
 }
 

Retrieving the values of output fields (ie. secondary results):

 List<? extends OutputField> outputFields = evaluator.getOutputFields();
 for(OutputField outputField : outputFields){
   FieldName outputName = outputField.getName();
   Object outputValue = results.get(outputName);
 }
 

Handling exceptions

A code block that does exception-prone work should be surrounded with two levels of try-catch statements. The inner try statement should catch EvaluationException instances that indicate "local" problems, which are related to individual data records. The outer try statement should catch InvalidMarkupException and UnsupportedMarkupException instances that indicate "global" problems, which are related to the class model object.

 try {
   List<Map<String, ?>> records = ...;
   for(Map<String, ?> record : records){
     try {
       // Do exception-prone work
     } catch(EvaluationException ee){
       // The work failed because of the data record.
       // Skip this data record and proceed as usual with the next one
     }
   }
 } catch(InvalidMarkupException | UnsupportedMarkupException me){
   // The work failed because of the class model object.
   // This is a persistent problem that is very likely to affect all data records
   // Decommission the Evaluator instance
 }
 

See Also:

EvaluatorUtil, HasGroupFields, HasOrderFields, HasModel, HasPMML

Field Summary

Fields

Modifier and Type	Field and Description
static org.dmg.pmml.FieldName	DEFAULT_TARGET_NAME The name of the default target field.

Method Summary

Modifier and Type	Method and Description
Map<org.dmg.pmml.FieldName,?>	evaluate(Map<org.dmg.pmml.FieldName,?> arguments) Evaluates the model with the specified arguments.
org.dmg.pmml.MiningFunction	getMiningFunction() Gets the type of the Model.
String	getSummary() Gets a short description of the Model.
Evaluator	verify() Verifies the model.

Methods inherited from interface org.jpmml.evaluator.HasInputFields

getInputFields

Methods inherited from interface org.jpmml.evaluator.HasActiveFields

getActiveFields

Methods inherited from interface org.jpmml.evaluator.HasResultFields

getOutputFields, getTargetFields

Field Detail

DEFAULT_TARGET_NAME

static final org.dmg.pmml.FieldName DEFAULT_TARGET_NAME

The name of the default target field.

Method Detail

getSummary

String getSummary()

Gets a short description of the Model.

getMiningFunction

org.dmg.pmml.MiningFunction getMiningFunction()

Gets the type of the Model.

verify

Evaluator verify()

Verifies the model.

Throws:

EvaluationException - If the verification fails.

InvalidMarkupException

UnsupportedMarkupException

evaluate

Map<org.dmg.pmml.FieldName,?> evaluate(Map<org.dmg.pmml.FieldName,?> arguments)

Evaluates the model with the specified arguments.

Parameters:

arguments - Map of input field values.

Returns:

Map of target field and output field values. A target field could be mapped to a complex value or a simple value. An output field is always mapped to a simple value. Complex values are represented as instances of Computable that return simple values. Simple values are represented using the Java equivalents of PMML data types (eg. String, Integer, Float, Double etc.). A missing value is represented by null.

Throws:

EvaluationException - If the evaluation fails.

InvalidMarkupException

UnsupportedMarkupException

See Also:

Computable