ModSQL
Class Literal

java.lang.Object
  |
  +--ModSQL.Literal

All Implemented Interfaces:

Function

final class Literal

extends Object

implements Function

Wrapper for literal values.

Author:

chris.studholme@utoronto.ca

Field Summary

protected int	type SQL type of value.
protected Object	value Literal value.

Fields inherited from interface ModSQL.Function

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

Constructor Summary

Literal()
Constructor for null value.

Literal(boolean b)
Constructor for boolean.

Literal(double d)
Constructor for double.

Literal(int i)
Constructor for integer.

Literal(long l)
Constructor for long.

Literal(Object s)
Constructor for java object.

Method Summary

void	addParameter(Function item) Adds a parameter to the list of parameters.
Object	evaluate(boolean aggregate) Returns the literal value.
Object	evaluate(int match_op, Object match_value) Returns the literal value.
void	evaluateOrder(int index, int order) Specify the order in which the parameters should be evaluated.
int	getMaxResultSize() If the literal is a String, this method returns the length of the String.
Function	getParameter(int index) Get a particular parameter.
int	getParameterCount() Get the number of parameters.
int	getSQLType() Return the SQL type of the literal value.
boolean	isAggregate() Determine if this function will return a value that is an aggregate of many database rows.
boolean	isConstant() Determine if this function returns a constant value.
void	optimize() Does nothing.
void	registerWith(Object o) Does nothing as a Literal has no parameters.
void	reset() Does nothing.
String	toString() Return human readable version of literal.

Methods inherited from class java.lang.Object

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

Field Detail

value

protected Object value

Literal value.

type

protected int type

SQL type of value.

Constructor Detail

Literal

public Literal()

Constructor for null value.

Literal

public Literal(Object s)

Constructor for java object.

Parameters:

s - object literal

Literal

public Literal(int i)

Constructor for integer.

Parameters:

i - integer literal

Literal

public Literal(long l)

Constructor for long.

Parameters:

l - long literal

Literal

public Literal(double d)

Constructor for double.

Parameters:

d - double literal

Literal

public Literal(boolean b)

Constructor for boolean.

Parameters:

b - boolean literal

Method Detail

toString

public String toString()

Return human readable version of literal.

Overrides:

toString in class Object

Returns:

human readable literal

getParameterCount

public int getParameterCount()

Get the number of parameters. Always returns 0 as parameters are not supported.

Specified by:

getParameterCount in interface Function

Returns:

number of parameters

getParameter

public Function getParameter(int index)

Get a particular parameter. Always throws an exception as parameters are not supported.

Specified by:

getParameter in interface Function

Parameters:

index - index of parameter to get

Returns:

parameter (function)

Throws:

IndexOutOfBoundsException - always

addParameter

public void addParameter(Function item)
                  throws SQLException

Adds a parameter to the list of parameters. Always throws an exception as parameters are not supported.

Specified by:

addParameter in interface Function

Parameters:

item - function to add

Throws:

SQLException - always

evaluateOrder

public void evaluateOrder(int index,
                          int order)

Specify the order in which the parameters should be evaluated. Always throws an exception as parameters are not supported.

Specified by:

evaluateOrder in interface Function

Parameters:

index - index of parameter

order - number indicating order in which parameter is evaluated

Throws:

IndexOutOfBoundsException - always

registerWith

public void registerWith(Object o)

Does nothing as a Literal has no parameters.

Specified by:

registerWith in interface Function

Parameters:

o - object to register with

optimize

public void optimize()

Does nothing.

Specified by:

optimize in interface Function

Following copied from interface: ModSQL.Function

Throws:

SQLException - if an error occurs

isConstant

public boolean isConstant()

Determine if this function returns a constant value. Always returns true for literal values.

Specified by:

isConstant in interface Function

Returns:

true

isAggregate

public boolean isAggregate()

Determine if this function will return a value that is an aggregate of many database rows. Always returns false for literal values.

Specified by:

isAggregate in interface Function

Returns:

false

getSQLType

public int getSQLType()

Return the SQL type of the literal value.

Specified by:

getSQLType in interface Function

Returns:

SQL type of data to be returned

getMaxResultSize

public int getMaxResultSize()

If the literal is a String, this method returns the length of the String. Otherwise, -1 is returned.

Specified by:

getMaxResultSize in interface Function

Returns:

length of String or -1 if literal is not a String

evaluate

public Object evaluate(boolean aggregate)

Returns the literal value.

Specified by:

evaluate in interface Function

Parameters:

aggregate - true to get final aggregate value

Returns:

result object

evaluate

public Object evaluate(int match_op,
                       Object match_value)

Returns the literal value.

Specified by:

evaluate in interface Function

Parameters:

match_op - how the value should be matched

match_value - desired value

Returns:

result object

reset

public void reset()

Does nothing.

Specified by:

reset in interface Function

Following copied from interface: ModSQL.Function

Throws:

SQLException - if an error occurs