ModSQL
Class Operator_Add

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

All Implemented Interfaces:

Function

final class Operator_Add

extends Operator

SQL operator "+".

Author:

chris.studholme@utoronto.ca

Field Summary

private Number	constant_value Sum of all constant parameters.
private int	return_type SQL 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_Add()

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 sum.
Object	evaluate(int match_op, Object match_value) Evaluate parameters and compute sum.
String	functionName() Returns "#ADD".
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

Sum of all constant parameters.

return_type

private int return_type

SQL return type of operator.

Constructor Detail

Operator_Add

Operator_Add()

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_Add, or Operator_Negate followed by Operator_Add, the functions parameters (summands) 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 determines the return type of the operator, evaluates all constant parameters and computes the sum of the constant parameters.

Overrides:

optimize in class AbstractFunction

Throws:

SQLException - if the parameters are invalid

functionName

public String functionName()

Returns "#ADD".

Overrides:

functionName in class AbstractFunction

Returns:

name of function

getSQLType

public int getSQLType()
               throws SQLException

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 sum.

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 sum.

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