org.apache.calcite.sql.type

Interface SqlSingleOperandTypeChecker

All Superinterfaces:

SqlOperandTypeChecker

All Known Implementing Classes:

ComparableOperandTypeChecker, CompositeSingleOperandTypeChecker, FamilyOperandTypeChecker, LiteralOperandTypeChecker, OperandMetadataImpl, SameOperandTypeChecker, SameOperandTypeExceptLastOperandChecker

public interface SqlSingleOperandTypeChecker
extends SqlOperandTypeChecker

SqlSingleOperandTypeChecker is an extension of SqlOperandTypeChecker for implementations which are capable of checking the type of a single operand in isolation. This isn't meaningful for all type-checking rules (e.g. SameOperandTypeChecker requires two operands to have matching types, so checking one in isolation is meaningless).

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.calcite.sql.type.SqlOperandTypeChecker

SqlOperandTypeChecker.Consistency

Method Summary

Modifier and Type	Method and Description
boolean	checkSingleOperandType(SqlCallBinding callBinding, SqlNode operand, int iFormalOperand, boolean throwOnFailure) Checks the type of a single operand against a particular ordinal position within a formal operator signature.

Methods inherited from interface org.apache.calcite.sql.type.SqlOperandTypeChecker

checkOperandTypes, getAllowedSignatures, getConsistency, getOperandCountRange, isFixedParameters, isOptional, typeInference

Method Detail

checkSingleOperandType

boolean checkSingleOperandType(SqlCallBinding callBinding,
                               SqlNode operand,
                               int iFormalOperand,
                               boolean throwOnFailure)

Checks the type of a single operand against a particular ordinal position within a formal operator signature. Note that the actual ordinal position of the operand being checked may be different from the position of the formal operand.

For example, when validating the actual call

C(X, Y, Z)

the strategy for validating the operand Z might involve checking its type against the formal signature OP(W). In this case, iFormalOperand would be zero, even though the position of Z within call C is two.

Caution that we could not(shouldn't) implement implicit type coercion for this checker, implicit type coercion has side effect(modify the AST), if this single operand checker is subsumed in a composite rule(OR or AND), we can not make any side effect if we can not make sure that all the single operands type check are passed(with type coercion). But there is an exception: only if the call has just one operand, for this case, use SqlOperandTypeChecker.checkOperandTypes(org.apache.calcite.sql.SqlCallBinding, boolean) instead.

Parameters:

callBinding - description of the call being checked; this is only provided for context when throwing an exception; the implementation should NOT examine the operands of the call as part of the check

operand - the actual operand to be checked

iFormalOperand - the 0-based formal operand ordinal

throwOnFailure - whether to throw an exception if check fails (otherwise returns false in that case)

Returns:

whether check succeeded