uk.ac.ic.doc.rodex.qproc
Class QueryFunction

java.lang.Object
  uk.ac.ic.doc.rodex.qproc.QueryFunction

public class QueryFunction
extends java.lang.Object

Constructor Summary

QueryFunction(AutoMedQueryToken operator, QueryVariable var, AutoMedType expression)
Creates a new instance of QueryFunction
Accepts an AutoMedType expression

Method Summary

static int	compareExpressions(AutoMedType t1, AutoMedType t2) Compare two AutoMedType expressions
static int	compareNumericExpressions(double f1, double f2)
static int	compareStringExpressions(java.lang.String s1, java.lang.String s2)
AutoMedType	getExpression()
AutoMedQueryToken	getOperator()
static AutoMedType[]	getValueRange(java.util.List funcs) Get a value range for a set of query functions This method supports two types of query expressions: numeric and literal
QueryVariable	getVariable()
boolean	isComparableTo(QueryFunction qf) Check if two functions are comparable, i.e.: the associated variables of the functions are mappable
boolean	isConsistentWith(QueryFunction qf) Check if this functions is consistent with another function.
boolean	isLiteral()
boolean	isMutuallyConsistentWith(QueryFunction qf) Check if two QueryFunction objects are mutually consistent Basically, this checks that this function is consistent with another function (see isConsistentWith(QueryFunction qf)) and the reverse.
boolean	isNumeric()
java.lang.String	toIQLString()
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

QueryFunction

public QueryFunction(AutoMedQueryToken operator,
                     QueryVariable var,
                     AutoMedType expression)

Creates a new instance of QueryFunction
Accepts an AutoMedType expression

Method Detail

getOperator

public AutoMedQueryToken getOperator()

getVariable

public QueryVariable getVariable()

getExpression

public AutoMedType getExpression()

isNumeric

public boolean isNumeric()

isLiteral

public boolean isLiteral()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

toIQLString

public java.lang.String toIQLString()

isComparableTo

public boolean isComparableTo(QueryFunction qf)

Check if two functions are comparable, i.e.:

• the associated variables of the functions are mappable

isMutuallyConsistentWith

public boolean isMutuallyConsistentWith(QueryFunction qf)

Check if two QueryFunction objects are mutually consistent
Basically, this checks that this function is consistent with another function
(see isConsistentWith(QueryFunction qf)) and the reverse.

Parameters:

qf - the other QueryFunction object

isConsistentWith

public boolean isConsistentWith(QueryFunction qf)

Check if this functions is consistent with another function. Two functions are consistent
iff all of the following conditions are true:

• the function expressions values are of the same type (i.e. comparable)
• the value ranges (sets) covered by two function expressions must overlap

To check mutual consistency, we must execute this function twice
one for each direction (see isMutuallyConsistentWith(QueryFunction qf))

This function should only be called after two functions have been
identified to be comparable, see isComparableTo(QueryFunction qf)

compareExpressions

public static int compareExpressions(AutoMedType t1,
                                     AutoMedType t2)

Compare two AutoMedType expressions

compareNumericExpressions

public static int compareNumericExpressions(double f1,
                                            double f2)

compareStringExpressions

public static int compareStringExpressions(java.lang.String s1,
                                           java.lang.String s2)

getValueRange

public static AutoMedType[] getValueRange(java.util.List funcs)

Get a value range for a set of query functions
This method supports two types of query expressions: numeric and literal

Parameters:

funcs - a List of QueryFunction objects

Returns:

AutoMedType[] an array of two AutoMedType objects, one for the lower bound and the other for the upper bound