io.cdap.cdap.etl.api.relational

Interface Expression

All Known Subinterfaces:

ExtractableExpression<T>

All Known Implementing Classes:

InvalidExtractableExpression

public interface Expression

Compiled scalar expression produced by ExpressionFactory.compile(T) that can be passed to various relational algebra calls of Relation objects. Note that relations, engine and expression factories must come from the same RelationalTranformContext and are valid only for the time of the RelationalTransform.transform(io.cdap.cdap.etl.api.relational.RelationalTranformContext) call.

Method Summary

Modifier and Type	Method and Description
String	getValidationError()
boolean	isValid()

Method Detail

isValid

boolean isValid()

Returns:

if this expression is valid. If during expression generation, it's found to be unsupported or invalid, generation will return an invalid Expression. Any Relation operation with invalid expression will result in an invalid Relation

See Also:

on operation problem details

getValidationError

String getValidationError()

Returns:

validation error if expression is not valid

See Also:

isValid()