ModSQL
Class Function_NVL

java.lang.Object
  |
  +--ModSQL.AbstractFunction
        |
        +--ModSQL.Function_NVL

All Implemented Interfaces:

Function

final class Function_NVL

extends AbstractFunction

SQL function for NVL (null value substitution function).

Author:

chris.studholme@utoronto.ca

Field Summary

private int

return_type Return type of function.

Fields inherited from class ModSQL.AbstractFunction

all_constant, constant_non_null, evaluate_order, evaluate_order_array, out_of_order, parameter_constant, parameter_value, parameters, parameters_array

Fields inherited from interface ModSQL.Function

MATCH_BEGINS, MATCH_EQU, MATCH_GT, MATCH_GTE, MATCH_LT, MATCH_LTE, MATCH_NE

Constructor Summary

(package private)

Function_NVL()

Method Summary

Object	evaluate(boolean aggregate) Evaluate parameters and compute the function.
static Function	forName(String name) If name is "nvl", this method returns an instance of this class.
String	functionName() Returns "#NVL".
int	getMaxResultSize() Make size of any String that may be returned, or -1 if a maximum size is not known.
int	getSQLType() Returns the SQL type of this function.
void	optimize() Prepare the function for use.

Methods inherited from class ModSQL.AbstractFunction

addParameter, convertToSQLType, evaluate, evaluateConstantParameters, evaluateOrder, evaluateParameters, evaluateParameters, getCompatableType, getObjectSQLType, getParameter, getParameterCount, isAggregate, isConstant, postfixParameters, prefixParameters, registerWith, reset, toString

Methods inherited from class java.lang.Object

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

Field Detail

return_type

private int return_type

Return type of function.

Constructor Detail

Function_NVL

Function_NVL()

Method Detail

forName

public static Function forName(String name)

If name is "nvl", this method returns an instance of this class.

Parameters:

name - name of desired function

Returns:

instance of this class, or null if name does not match

optimize

public void optimize()
              throws SQLException

Prepare the function for use.

Overrides:

optimize in class AbstractFunction

Throws:

SQLException - if the parameters are invalid

getSQLType

public int getSQLType()

Returns the SQL type of this function.

Returns:

SQL type of data to be returned

getMaxResultSize

public int getMaxResultSize()
                     throws SQLException

Make size of any String that may be returned, or -1 if a maximum size is not known.

Returns:

maximum size of String returned or -1 if unknown

Throws:

SQLException - if thrown by a parameter

functionName

public String functionName()

Returns "#NVL".

Overrides:

functionName in class AbstractFunction

Returns:

name of function

evaluate

public Object evaluate(boolean aggregate)
                throws SQLException,
                       EndOfTable

Evaluate parameters and compute the function.

Parameters:

aggregate - passed to parameter

Returns:

result object

Throws:

SQLException - if a database-access error occurs

EndOfTable - if thrown by a parameter