org.eigenbase.sql.type
Class CompositeOperandTypeChecker

java.lang.Object
  org.eigenbase.sql.type.CompositeOperandTypeChecker

All Implemented Interfaces:

SqlOperandTypeChecker, SqlSingleOperandTypeChecker

public class CompositeOperandTypeChecker
extends Object
implements SqlSingleOperandTypeChecker

This class allows multiple existing SqlOperandTypeChecker rules to be combined into one rule. For example, allowing an operand to be either string or numeric could be done by:

 CompositeOperandsTypeChecking newCompositeRule =
  new CompositeOperandsTypeChecking(
    Composition.OR,
    new SqlOperandTypeChecker[]{stringRule, numericRule});

 

Similary a rule that would only allow a numeric literal can be done by:

 CompositeOperandsTypeChecking newCompositeRule =
  new CompositeOperandsTypeChecking(
    Composition.AND,
    new SqlOperandTypeChecker[]{numericRule, literalRule});

 

Finally, creating a signature expecting a string for the first operand and a numeric for the second operand can be done by:

 CompositeOperandsTypeChecking newCompositeRule =
  new CompositeOperandsTypeChecking(
    Composition.SEQUENCE,
    new SqlOperandTypeChecker[]{stringRule, numericRule});

 

For SEQUENCE composition, the rules must be instances of SqlSingleOperandTypeChecker, and signature generation is not supported. For AND composition, only the first rule is used for signature generation.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/sql/type/CompositeOperandTypeChecker.java#9 $

Author:

Wael Chatila

Nested Class Summary

static class

CompositeOperandTypeChecker.Composition

Field Summary

private SqlOperandTypeChecker[]	allowedRules
private CompositeOperandTypeChecker.Composition	composition

Constructor Summary

CompositeOperandTypeChecker(CompositeOperandTypeChecker.Composition composition, SqlOperandTypeChecker... allowedRules)

Method Summary

boolean	checkOperandTypes(SqlCallBinding callBinding, boolean throwOnFailure) Checks the types of all operands to an operator call.
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.
SqlOperandCountRange	getOperandCountRange()
SqlOperandTypeChecker[]	getRules()

Methods inherited from class java.lang.Object

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

Field Detail

allowedRules

private final SqlOperandTypeChecker[] allowedRules

composition

private final CompositeOperandTypeChecker.Composition composition

Constructor Detail

CompositeOperandTypeChecker

public CompositeOperandTypeChecker(CompositeOperandTypeChecker.Composition composition,
                                   SqlOperandTypeChecker... allowedRules)

Method Detail

getRules

public SqlOperandTypeChecker[] getRules()

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

getOperandCountRange

public SqlOperandCountRange getOperandCountRange()

Specified by:

getOperandCountRange in interface SqlOperandTypeChecker

Returns:

range of operand counts allowed in a call

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.

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

checkOperandTypes

public boolean checkOperandTypes(SqlCallBinding callBinding,
                                 boolean throwOnFailure)

Description copied from interface: SqlOperandTypeChecker

Checks the types of all operands to an operator call.

Specified by:

checkOperandTypes in interface SqlOperandTypeChecker

Parameters:

callBinding - description of the call to be checked

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

Returns:

whether check succeeded