Package org.apache.calcite.sql.fun

Class SqlTranslateFunction

java.lang.Object

org.apache.calcite.sql.SqlOperator

org.apache.calcite.sql.SqlFunction

org.apache.calcite.sql.fun.SqlConvertFunction

org.apache.calcite.sql.fun.SqlTranslateFunction

public class SqlTranslateFunction
extends SqlConvertFunction

Common base for the TRANSLATE(USING) and CONVERT(USING) function, which is different from SqlLibraryOperators.TRANSLATE3 and SqlLibraryOperators.MSSQL_CONVERT.

The SQL syntax is

   TRANSLATE(characterString USING transcodingName)
 

or

   CONVERT(characterString USING transcodingName)
 

Field Summary

Fields inherited from class org.apache.calcite.sql.SqlOperator

kind, MDX_PRECEDENCE, NL

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	SqlTranslateFunction(String name)

Method Summary

Modifier and Type	Method	Description
boolean	checkOperandTypes(SqlCallBinding callBinding, boolean throwOnFailure)	Checks that the operand values in a SqlCall to this operator are valid.
RelDataType	deriveType(SqlValidator validator, SqlValidatorScope scope, SqlCall call)	Derives the type of a call to this operator.
SqlOperandCountRange	getOperandCountRange()	Returns a constraint on the number of operands expected by this operator.
String	getSignatureTemplate(int operandsCount)	Returns a template describing how the operator signature is to be built.
RelDataType	inferReturnType(SqlOperatorBinding opBinding)	Infers the return type of an invocation of this operator; only called after the number and types of operands have already been validated.
void	unparse(SqlWriter writer, SqlCall call, int leftPrec, int rightPrec)	Writes a SQL representation of a call to this operator to a writer, including parentheses if the operators on either side are of greater precedence.
void	validateCall(SqlCall call, SqlValidator validator, SqlValidatorScope scope, SqlValidatorScope operandScope)	Validates a call to this operator.

Methods inherited from class org.apache.calcite.sql.fun.SqlConvertFunction

acceptCall

Methods inherited from class org.apache.calcite.sql.SqlFunction

getFunctionType, getNameAsId, getParamNames, getParamTypes, getSqlIdentifier, getSyntax, isQuantifierAllowed, validateQuantifier

Methods inherited from class org.apache.calcite.sql.SqlOperator

acceptCall, adjustType, allowsFraming, argumentMustBeScalar, checkOperandCount, constructArgNameList, constructArgTypeList, constructOperandList, createCall, createCall, createCall, createCall, createCall, createCall, createCall, deriveOperandType, equals, getAllowedSignatures, getAllowedSignatures, getKind, getLeftPrec, getMonotonicity, getMonotonicity, getName, getOperandTypeChecker, getOperandTypeInference, getReturnTypeInference, getRightPrec, getSqlCallFactory, getStrongPolicyInference, hashCode, inferReturnType, isAggregator, isDeterministic, isDynamicFunction, isGroup, isGroupAuxiliary, isName, isSymmetrical, leftPrec, not, preValidateCall, requiresDecimalExpansion, requiresOrder, requiresOver, reverse, rewriteCall, rightPrec, toString, unparseListClause, unparseListClause, validateOperands, validRexOperands

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Details

SqlTranslateFunction

protected SqlTranslateFunction(String name)

Method Details

validateCall

public void validateCall(SqlCall call,
 SqlValidator validator,
 SqlValidatorScope scope,
 SqlValidatorScope operandScope)

Description copied from class: SqlOperator

Validates a call to this operator.

This method should not perform type-derivation or perform validation related related to types. That is done later, by SqlOperator.deriveType(SqlValidator, SqlValidatorScope, SqlCall). This method should focus on structural validation.

A typical implementation of this method first validates the operands, then performs some operator-specific logic. The default implementation just validates the operands.

This method is the default implementation of SqlCall.validate(org.apache.calcite.sql.validate.SqlValidator, org.apache.calcite.sql.validate.SqlValidatorScope); but note that some sub-classes of SqlCall never call this method.

Overrides:

validateCall in class SqlConvertFunction

Parameters:

call - the call to this operator

validator - the active validator

scope - validator scope

operandScope - validator scope in which to validate operands to this call; usually equal to scope, but not always because some operators introduce new scopes

See Also:

• SqlNode.validateExpr(SqlValidator, SqlValidatorScope)
• SqlOperator.deriveType(SqlValidator, SqlValidatorScope, SqlCall)

inferReturnType

public RelDataType inferReturnType(SqlOperatorBinding opBinding)

Description copied from class: SqlOperator

Infers the return type of an invocation of this operator; only called after the number and types of operands have already been validated. Subclasses must either override this method or supply an instance of SqlReturnTypeInference to the constructor.

Overrides:

inferReturnType in class SqlConvertFunction

Parameters:

opBinding - description of invocation (not necessarily a SqlCall)

Returns:

inferred return type

deriveType

public RelDataType deriveType(SqlValidator validator,
 SqlValidatorScope scope,
 SqlCall call)

Description copied from class: SqlOperator

Derives the type of a call to this operator.

This method is an intrinsic part of the validation process so, unlike SqlOperator.inferReturnType(org.apache.calcite.sql.SqlOperatorBinding), specific operators would not typically override this method.

Overrides:

deriveType in class SqlConvertFunction

Parameters:

validator - Validator

scope - Scope of validation

call - Call to this operator

Returns:

Type of call

checkOperandTypes

public boolean checkOperandTypes(SqlCallBinding callBinding,
 boolean throwOnFailure)

Description copied from class: SqlOperator

Checks that the operand values in a SqlCall to this operator are valid. Subclasses must either override this method or supply an instance of SqlOperandTypeChecker to the constructor.

Overrides:

checkOperandTypes in class SqlConvertFunction

Parameters:

callBinding - description of call

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

Returns:

whether check succeeded

getSignatureTemplate

public String getSignatureTemplate(int operandsCount)

Description copied from class: SqlOperator

Returns a template describing how the operator signature is to be built. E.g for the binary + operator the template looks like "{1} {0} {2}" {0} is the operator, subsequent numbers are operands.

Overrides:

getSignatureTemplate in class SqlConvertFunction

Parameters:

operandsCount - is used with functions that can take a variable number of operands

Returns:

signature template, or null to indicate that a default template will suffice

getOperandCountRange

public SqlOperandCountRange getOperandCountRange()

Description copied from class: SqlOperator

Returns a constraint on the number of operands expected by this operator. Subclasses may override this method; when they don't, the range is derived from the SqlOperandTypeChecker associated with this operator.

Overrides:

getOperandCountRange in class SqlConvertFunction

Returns:

acceptable range

unparse

public void unparse(SqlWriter writer,
 SqlCall call,
 int leftPrec,
 int rightPrec)

Description copied from class: SqlOperator

Writes a SQL representation of a call to this operator to a writer, including parentheses if the operators on either side are of greater precedence.

The default implementation of this method delegates to SqlSyntax.unparse(org.apache.calcite.sql.SqlWriter, org.apache.calcite.sql.SqlOperator, org.apache.calcite.sql.SqlCall, int, int).

Overrides:

unparse in class SqlConvertFunction