dragon.ir.query

Interface Predicate

All Superinterfaces:

IRQuery

All Known Implementing Classes:

AbstractPredicate, BoolQualifierPredicate, BoolRelationPredicate, BoolTermPredicate, SimpleRelationPredicate, SimpleTermPredicate

public interface Predicate
extends IRQuery

Interface of predicate which is the least unit of IR query

Copyright: Copyright (c) 2005

Company: IST, Drexel University

Version:

1.0

Author:

Davis Zhou

Field Summary

Fields

Modifier and Type	Field and Description
static int	PREDICATE_BOOL
static int	PREDICATE_QUALIFIER
static int	PREDICATE_RELATION
static int	PREDICATE_SIMPLE
static int	PREDICATE_TERM

Method Summary

Modifier and Type	Method and Description
Expression	getConstraint()
double	getSelectivity()
double	getWeight()
boolean	isBoolPredicate()
boolean	isQualifierPredicate()
boolean	isRelationPredicate()
boolean	isSimplePredicate()
boolean	isTermPredicate()
void	setWeight(double weight)
String	toSQLExpression()
String	toString()

Methods inherited from interface dragon.ir.query.IRQuery

getChild, getChildNum, getOperator, getQueryKey, isCompoundQuery, isPredicate, isRelBoolQuery, isRelSimpleQuery, parse, setQueryKey

Field Detail

PREDICATE_TERM

static final int PREDICATE_TERM

See Also:

Constant Field Values

PREDICATE_RELATION

static final int PREDICATE_RELATION

See Also:

Constant Field Values

PREDICATE_QUALIFIER

static final int PREDICATE_QUALIFIER

See Also:

Constant Field Values

PREDICATE_SIMPLE

static final int PREDICATE_SIMPLE

See Also:

Constant Field Values

PREDICATE_BOOL

static final int PREDICATE_BOOL

See Also:

Constant Field Values

Method Detail

getSelectivity

double getSelectivity()

Specified by:

getSelectivity in interface IRQuery

Returns:

a double socre indicating how specific the query predicate is.

getWeight

double getWeight()

setWeight

void setWeight(double weight)

isSimplePredicate

boolean isSimplePredicate()

isBoolPredicate

boolean isBoolPredicate()

isTermPredicate

boolean isTermPredicate()

isRelationPredicate

boolean isRelationPredicate()

isQualifierPredicate

boolean isQualifierPredicate()

getConstraint

Expression getConstraint()

Returns:

the underlying expression of the current predicate

toSQLExpression

String toSQLExpression()

toString

String toString()

Specified by:

toString in interface IRQuery

Overrides:

toString in class Object