Package org.apache.calcite.sql.type

Class LiteralOperandTypeChecker

java.lang.Object

org.apache.calcite.sql.type.LiteralOperandTypeChecker

All Implemented Interfaces:

SqlOperandTypeChecker, SqlSingleOperandTypeChecker

public class LiteralOperandTypeChecker
extends Object
implements SqlSingleOperandTypeChecker

Parameter type-checking strategy type must be a literal (whether null is allowed is determined by the constructor). CAST(NULL as ...) is considered to be a NULL literal but not CAST(CAST(NULL as ...) AS ...)

Nested Class Summary

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

SqlOperandTypeChecker.Consistency

Constructor Summary

Constructors

Constructor	Description
LiteralOperandTypeChecker(boolean allowNull)

Method Summary

Modifier and Type	Method	Description
boolean	checkSingleOperandType(SqlCallBinding callBinding, SqlNode node, int iFormalOperand, boolean throwOnFailure)	Checks the type of a single operand against a particular ordinal position within a formal operator signature.
String	getAllowedSignatures(SqlOperator op, String opName)	Returns a string describing the allowed formal signatures of a call, e.g.

Methods inherited from class java.lang.Object

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

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

and, getConsistency, isFixedParameters, isOptional, or, typeInference, withGenerator

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

and, checkOperandTypes, getOperandCountRange, or

Constructor Details

LiteralOperandTypeChecker

public LiteralOperandTypeChecker(boolean allowNull)

Method Details

checkSingleOperandType

public boolean checkSingleOperandType(SqlCallBinding callBinding,
 SqlNode node,
 int iFormalOperand,
 boolean throwOnFailure)

Description copied from interface: SqlSingleOperandTypeChecker

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.

Specified by:

checkSingleOperandType in interface SqlSingleOperandTypeChecker

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

node - 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

getAllowedSignatures

public String getAllowedSignatures(SqlOperator op,
 String opName)

Description copied from interface: SqlOperandTypeChecker

Returns a string describing the allowed formal signatures of a call, e.g. "SUBSTR(VARCHAR, INTEGER, INTEGER)".

Specified by:

getAllowedSignatures in interface SqlOperandTypeChecker

Parameters:

op - the operator being checked

opName - name to use for the operator in case of aliasing

Returns:

generated string