org.proteios.core.query
Class Aggregations

java.lang.Object
  org.proteios.core.query.Aggregations

public class Aggregations
extends Object

A factory class to create aggregate expressions.

Version:

2.0

Author:

Nicklas

Last modified

$Date: 2009-04-09 08:48:11 +0200 (Thu, 09 Apr 2009) $

Constructor Summary

Aggregations()

Method Summary

static Expression	count(Expression e, boolean distinct) Calculates the number of values for an expression: new expression = COUNT(e)
static Expression	max(Expression e) Calculates the maximum value of an expression: new expression = MAX(e)
static Expression	mean(Expression e) Calculates the mean of all values for an expression: new expression = AVG(e)
static Expression	min(Expression e) Calculates the minimum value of an expression: new expression = MIN(e)
static Expression	sum(Expression e) Calculates the sum of all values of an expression: new expression = SUM(e)

Methods inherited from class java.lang.Object

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

Constructor Detail

Aggregations

public Aggregations()

Method Detail

count

public static Expression count(Expression e,
                               boolean distinct)

Calculates the number of values for an expression: new expression = COUNT(e)

Parameters:

e - The expression to count, or null to count all rows (ie. COUNT(*))

distinct - If only distinct values should be counted

Returns:

The new Expression

max

public static Expression max(Expression e)
                      throws InvalidDataException

Calculates the maximum value of an expression: new expression = MAX(e)

Parameters:

e - The expression to use in the calculation

Returns:

The new Expression

Throws:

InvalidDataException - If the expression is null

min

public static Expression min(Expression e)
                      throws InvalidDataException

Calculates the minimum value of an expression: new expression = MIN(e)

Parameters:

e - The expression to use in the calculation

Returns:

The new Expression

Throws:

InvalidDataException - If the expression is null

mean

public static Expression mean(Expression e)
                       throws InvalidDataException

Calculates the mean of all values for an expression: new expression = AVG(e)

Parameters:

e - The expression to use in the calculation

Returns:

The new Expression

Throws:

InvalidDataException - If the expression is null

sum

public static Expression sum(Expression e)
                      throws InvalidDataException

Calculates the sum of all values of an expression: new expression = SUM(e)

Parameters:

e - The expression to use in the calculation

Returns:

The new Expression

Throws:

InvalidDataException - If the expression is null