ModSQL
Class Operator_Multiply

java.lang.Object
  |
  +--ModSQL.AbstractFunction
        |
        +--ModSQL.Operator
              |
              +--ModSQL.Operator_Multiply

All Implemented Interfaces:

Function

final class Operator_Multiply

extends Operator

SQL operator "*".

Author:

chris.studholme@utoronto.ca

Field Summary

private Number	constant_value Product of constant parameters.
private int	return_type Return type of operator.

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)

Operator_Multiply()

Method Summary

void	addParameter(Function function) Adds a function to the list of parameters maintained by this operator.
Object	evaluate(boolean aggregate) Evaluate parameters and compute the function.
Object	evaluate(int match_op, Object match_value) Evaluate parameters and compute the function.
String	functionName() Returns "#MULT".
int	getMaxResultSize() Returns -1 as this operator will never return a String object.
int	getSQLType() Return the SQL type of the value that this function expects to return.
void	optimize() Prepare the function for use.

Methods inherited from class ModSQL.Operator

addAllParameters, addAllParametersNegate, addAllParametersNot, removeDoubleNegation, removeDoubleNot

Methods inherited from class ModSQL.AbstractFunction

convertToSQLType, 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

constant_value

private Number constant_value

Product of constant parameters.

return_type

private int return_type

Return type of operator.

Constructor Detail

Operator_Multiply

Operator_Multiply()

Method Detail

addParameter

public void addParameter(Function function)
                  throws SQLException

Adds a function to the list of parameters maintained by this operator. If the function is of type Operator_Negate and has double negation, the double negation will be removed. If the function is of type Operator_Multiply, or Operator_Negate followed by Operator_Multiply, the functions parameters (factors) are added instead of the function.

Overrides:

addParameter in class AbstractFunction

Parameters:

function - function to add

Throws:

SQLException - if a database error occurs

optimize

public void optimize()
              throws SQLException

Prepare the function for use. This method checks the parameters, figures out an appropriate return type, and computes the product of all constant parameters.

Overrides:

optimize in class AbstractFunction

Throws:

SQLException - if the parameters are invalid

functionName

public String functionName()

Returns "#MULT".

Overrides:

functionName in class AbstractFunction

Returns:

name of function

getSQLType

public int getSQLType()

Return the SQL type of the value that this function expects to return. The data returned by the function must either be of this type, or null.

Returns:

SQL type of data to be returned

getMaxResultSize

public int getMaxResultSize()

Returns -1 as this operator will never return a String object.

Returns:

maximum size of String returned or -1 if unknown

evaluate

public Object evaluate(boolean aggregate)
                throws SQLException,
                       EndOfTable

Evaluate parameters and compute the function.

Parameters:

aggregate - passed to parameters

Returns:

result object

Throws:

SQLException - if a database-access error occurs

EndOfTable - if thrown by a parameter

evaluate

public Object evaluate(int match_op,
                       Object match_value)
                throws SQLException,
                       EndOfTable

Evaluate parameters and compute the function.

Overrides:

evaluate in class AbstractFunction

Parameters:

match_op - how the value should be matched

match_value - desired value

Returns:

result object

Throws:

SQLException - if a database-access error occurs

EndOfTable - if thrown by a parameter