org.eigenbase.sql.fun
Class SqlCastFunction

java.lang.Object
  org.eigenbase.sql.SqlOperator
      org.eigenbase.sql.SqlFunction
          org.eigenbase.sql.fun.SqlCastFunction

public class SqlCastFunction
extends SqlFunction

SqlCastFunction. Note that the std functions are really singleton objects, because they always get fetched via the StdOperatorTable. So you can't store any local info in the class and hence the return type data is maintained in operand[1] through the validation phase.

Since:

Jun 5, 2004

Version:

$Id: //open/dev/farrago/src/org/eigenbase/sql/fun/SqlCastFunction.java#24 $

Author:

lee

Nested Class Summary

private class

SqlCastFunction.TypeFamilyCast

Field Summary

private Set<SqlCastFunction.TypeFamilyCast>

nonMonotonicPreservingCasts

Fields inherited from class org.eigenbase.sql.SqlOperator

MaxPrec, NL

Constructor Summary

SqlCastFunction()

Method Summary

boolean	checkOperandTypes(SqlCallBinding callBinding, boolean throwOnFailure) Makes sure that the number and types of arguments are allowable.
private Set<SqlCastFunction.TypeFamilyCast>	createNonMonotonicPreservingCasts()
SqlMonotonicity	getMonotonicity(SqlCall call, SqlValidatorScope scope) Returns whether this operator is monotonic.
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.
SqlSyntax	getSyntax() Returns the syntactic type of this operator.
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.
private boolean	isMonotonicPreservingCast(RelDataTypeFamily castFrom, RelDataTypeFamily castTo)
void	unparse(SqlWriter writer, SqlNode[] operands, 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.

Methods inherited from class org.eigenbase.sql.SqlFunction

deriveType, getFunctionType, getNameAsId, getParamTypes, getSqlIdentifier, isQuantifierAllowed, validateCall, validateQuantifier

Methods inherited from class org.eigenbase.sql.SqlOperator

acceptCall, acceptCall, adjustType, argumentMustBeScalar, checkOperandCount, createCall, createCall, createCall, createCall, equals, getAllowedSignatures, getAllowedSignatures, getKind, getLeftPrec, getName, getOperandTypeChecker, getOperandTypeInference, getReturnTypeInference, getRightPrec, hashCode, inferReturnType, isAggregator, isDeterministic, isDynamicFunction, isName, leftPrec, preValidateCall, requiresDecimalExpansion, rewriteCall, rightPrec, toString, unparseListClause, unparseListClause, validateOperands

Methods inherited from class java.lang.Object

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

Field Detail

nonMonotonicPreservingCasts

private final Set<SqlCastFunction.TypeFamilyCast> nonMonotonicPreservingCasts

Constructor Detail

SqlCastFunction

public SqlCastFunction()

Method Detail

createNonMonotonicPreservingCasts

private Set<SqlCastFunction.TypeFamilyCast> createNonMonotonicPreservingCasts()

isMonotonicPreservingCast

private boolean isMonotonicPreservingCast(RelDataTypeFamily castFrom,
                                          RelDataTypeFamily castTo)

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 SqlOperator

Parameters:

opBinding - description of invocation (not necessarily a SqlCall)

Returns:

inferred return type

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 SqlOperator

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 SqlOperator

Returns:

acceptable range

checkOperandTypes

public boolean checkOperandTypes(SqlCallBinding callBinding,
                                 boolean throwOnFailure)

Makes sure that the number and types of arguments are allowable. Operators (such as "ROW" and "AS") which do not check their arguments can override this method.

Overrides:

checkOperandTypes in class SqlOperator

Parameters:

callBinding - description of call

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

Returns:

whether check succeeded

getSyntax

public SqlSyntax getSyntax()

Description copied from class: SqlOperator

Returns the syntactic type of this operator.

Overrides:

getSyntax in class SqlFunction

unparse

public void unparse(SqlWriter writer,
                    SqlNode[] operands,
                    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.eigenbase.sql.SqlWriter, org.eigenbase.sql.SqlOperator, org.eigenbase.sql.SqlNode[], int, int).

Overrides:

unparse in class SqlFunction

getMonotonicity

public SqlMonotonicity getMonotonicity(SqlCall call,
                                       SqlValidatorScope scope)

Description copied from class: SqlOperator

Returns whether this operator is monotonic.

Default implementation returns SqlMonotonicity.NotMonotonic.

Overrides:

getMonotonicity in class SqlOperator

Parameters:

call - Call to this operator

scope - Scope in which the call occurs