ModSQL
Class Function_String

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

All Implemented Interfaces:

Function

final class Function_String

extends AbstractFunction

SQL function for string operations.

Function_String provides: LEFT, RIGHT, UPPER, LOWER, INITCAP, LENGTH, LPAD, RPAD, and SUBSTR.

Author:

chris.studholme@utoronto.ca

Field Summary

static int	INITCAP Function is INITCAP().
static int	LEFT Function is LEFT().
static int	LENGTH Function is LENGTH().
static int	LOWER Function is LOWER().
static int	LPAD Function is LPAD().
private int	op Which function are we? One of the above constants.
static int	RIGHT Function is RIGHT().
static int	RPAD Function is RPAD().
static int	SUBSTR Function is SUBSTR().
static int	UPPER Function is UPPER().

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

Function_String(int op)
Constructor.

Method Summary

Object	evaluate(boolean aggregate) Evaluate parameters and compute function.
static Function	forName(String name) Returns a new instance of this class if name is recognized.
String	functionName() Returns the name of this function for use by toString() method.
int	getMaxResultSize() Returns the maximum size of any String computed by this function.
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

LEFT

public static final int LEFT

Function is LEFT().

RIGHT

public static final int RIGHT

Function is RIGHT().

UPPER

public static final int UPPER

Function is UPPER().

LOWER

public static final int LOWER

Function is LOWER().

INITCAP

public static final int INITCAP

Function is INITCAP().

LENGTH

public static final int LENGTH

Function is LENGTH().

LPAD

public static final int LPAD

Function is LPAD().

RPAD

public static final int RPAD

Function is RPAD().

SUBSTR

public static final int SUBSTR

Function is SUBSTR().

op

private int op

Which function are we? One of the above constants.

Constructor Detail

Function_String

public Function_String(int op)

Constructor.

Parameters:

op - function type

Method Detail

forName

public static Function forName(String name)

Returns a new instance of this class if name is recognized. The instance is initialized as needed to represent the desired function.

Parameters:

name - name of function to find

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()
               throws SQLException

Returns the SQL type of this function.

Returns:

SQL type of data to be returned

getMaxResultSize

public int getMaxResultSize()
                     throws SQLException

Returns the maximum size of any String computed by this function. If a maximum size cannot be determined or this function does not return a String (ie. LENGTH), -1 is returned.

Returns:

maximum size of String returned or -1 if unknown

functionName

public String functionName()

Returns the name of this function for use by toString() method.

Overrides:

functionName in class AbstractFunction

Returns:

name of function

evaluate

public Object evaluate(boolean aggregate)
                throws SQLException,
                       EndOfTable

Evaluate parameters and compute function.

Parameters:

aggregate - passed to parameters

Returns:

result object

Throws:

SQLException - if a database-access error occurs

EndOfTable - if thrown by a parameter