Main Page | Class Hierarchy | Class List | Class Members

kddml.Core.QueryElement.Expression.Expression Class Reference

Inheritance diagram for kddml.Core.QueryElement.Expression.Expression:

kddml.Core.QueryElement.XMLSpecialElement kddml.Core.KDDMLObject kddml.Core.HTMLTranslator kddml.Core.QueryElement.Expression.BaseTerm kddml.Core.QueryElement.Expression.IfTerm kddml.Core.QueryElement.Expression.SeqTerm List of all members.

Public Member Functions

abstract String evalExpr (Instance instance) throws KDDMLCoreException
KDDMLObjectType getType ()

Detailed Description

An expression as used in KDD Query. This object is used to represent language expressions. Expressions are similar to conditions, but they return a scalar (i.e., a number of string) instead of a boolean value. Expression admits a sequential statement (element SEQ TERM), including basic operations (such as sum, multiplication, subtraction, division of numbers and concatenation of strings) on primitive terms of the expression.
Also a conditional statement (element IF TERM) is admitted. It is used to evaluate a then statement or an (optional) else statement according to a condition.
Finally, the element BASE TERM is used to provide numeric/string constants or table attribute names (as for conditions, with the special symbol "@" in the value attribute of the BASE TERM element we denote an input table column).

Title: KDDML

Description: Knowledge Discovery in Database Environment

Copyright: Copyright (c) 2003-2005

Company: Universita' di Pisa - Dipartimento di Informatica

Author:
Andrea Romei (romei@di.unipi.it)

Sandra Zimei

Version:
2.0.16


Member Function Documentation

abstract String kddml.Core.QueryElement.Expression.Expression.evalExpr Instance  instance  )  throws KDDMLCoreException [pure virtual]
 

Evaluates the expression on input instance. The tupla is defined in weka.core.Instance class.

Parameters:
instance Instance the input instance as in weka.core.Instance.
Exceptions:
KDDMLCoreException 
Returns:
String the expression evaluation as string.

Implemented in kddml.Core.QueryElement.Expression.BaseTerm, kddml.Core.QueryElement.Expression.IfTerm, and kddml.Core.QueryElement.Expression.SeqTerm.

KDDMLObjectType kddml.Core.QueryElement.Expression.Expression.getType  )  [virtual]
 

Returns the type of the object.

Returns:
KDDMLObjectType the type of this object

Implements kddml.Core.KDDMLObject.


Generated on Thu Feb 23 13:04:45 2006 for kddml by  doxygen 1.4.3