Module datarush.library

Package com.pervasive.datarush.functions

Class MappedEvaluatorFactory

java.lang.Object

com.pervasive.datarush.functions.MappedEvaluatorFactory

All Implemented Interfaces:

EvaluatorFactory

Direct Known Subclasses:

InputMappedFactory, ResultMappedFactory

public abstract class MappedEvaluatorFactory
extends Object
implements EvaluatorFactory

A base class for factories which choose an evaluator based on a token type. The mapping is static, defined at construction, and uses reflection to create the evaluator. Lookup is by exact match; type assignability is not taken into account.

See Also:

• ReflectiveFactory

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	MappedEvaluatorFactory.Mapping	Defines a mapping between data type and an evaluator class.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	MappedEvaluatorFactory()	Creates a factory with no mapping.
protected	MappedEvaluatorFactory(MappedEvaluatorFactory.Mapping... mappings)	Creates a factory using the supplied mappings.

Method Summary

Modifier and Type	Method	Description
FunctionEvaluator	contructEvaluator(ScalarSettable result, Object[] arguments)	Construct a new evaluator for the associated function with the given arguments, bound to the specified output buffer.
protected abstract ScalarTokenType	getDispatchType(ScalarSettable result, Object[] arguments)	Determines the type to use to select the evaluator.
static MappedEvaluatorFactory.Mapping	use(ScalarTokenType type, Class<? extends FunctionEvaluator> evaluator)	Defines the evaluator class for a given type.

Methods inherited from class java.lang.Object

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

Constructor Details

MappedEvaluatorFactory

protected MappedEvaluatorFactory()

Creates a factory with no mapping. This constructor is provided only for serialization support.

MappedEvaluatorFactory

protected MappedEvaluatorFactory(MappedEvaluatorFactory.Mapping... mappings)

Creates a factory using the supplied mappings.

Parameters:

mappings - the type to evaluator mappings to use

Method Details

use

public static MappedEvaluatorFactory.Mapping use(ScalarTokenType type,
 Class<? extends FunctionEvaluator> evaluator)

Defines the evaluator class for a given type.

Parameters:

type - the token type for which to define a mapping

evaluator - the class of the evaluator to create

Returns:

a mapping

getDispatchType

protected abstract ScalarTokenType getDispatchType(ScalarSettable result,
 Object[] arguments)

Determines the type to use to select the evaluator.

Parameters:

result - the result buffer for the function

arguments - the arguments to the function

Returns:

the type to use to lookup the evaluator

contructEvaluator

public FunctionEvaluator contructEvaluator(ScalarSettable result,
 Object[] arguments)

Description copied from interface: EvaluatorFactory

Construct a new evaluator for the associated function with the given arguments, bound to the specified output buffer.

Specified by:

contructEvaluator in interface EvaluatorFactory

Parameters:

result - the buffer to which the function result is written

arguments - the arguments to the function

Returns:

a new evaluator for the function