dragon.ir.query

Class AbstractPredicate

java.lang.Object

dragon.ir.query.AbstractIRQuery

dragon.ir.query.AbstractPredicate

All Implemented Interfaces:

IRQuery, Predicate

Direct Known Subclasses:

BoolQualifierPredicate, BoolRelationPredicate, BoolTermPredicate, SimpleRelationPredicate, SimpleTermPredicate

public abstract class AbstractPredicate
extends AbstractIRQuery
implements Predicate

Abstract class of predicate

Copyright: Copyright (c) 2005

Company: IST, Drexel University

Version:

1.0

Author:

Davis Zhou

Field Summary

Fields

Modifier and Type	Field and Description
protected Expression	constraint
protected int	expressionType
protected int	predicateType
protected double	weight

Fields inherited from class dragon.ir.query.AbstractIRQuery

children, optr

Fields inherited from interface dragon.ir.query.Predicate

PREDICATE_BOOL, PREDICATE_QUALIFIER, PREDICATE_RELATION, PREDICATE_SIMPLE, PREDICATE_TERM

Constructor Summary

Constructors

Constructor and Description
AbstractPredicate()

Method Summary

Modifier and Type	Method and Description
IRQuery	getChild(int index)
int	getChildNum()
Expression	getConstraint()
Operator	getOperator()
double	getSelectivity()
double	getWeight()
boolean	isBoolPredicate()
boolean	isCompoundQuery() If the current query denotes a simple predicate, this method returns false, otherwise true.
boolean	isPredicate() A predicate always begins with a ltter T (term predicate), R(relation predicate), or M(modifier predicate)
boolean	isQualifierPredicate()
boolean	isRelationPredicate()
boolean	isSimplePredicate()
boolean	isTermPredicate()
boolean	parse(String predicate)
protected abstract void	parse(String[] predicate)
void	setWeight(double weight)

Methods inherited from class dragon.ir.query.AbstractIRQuery

getQueryKey, getTokenList, isRelBoolQuery, isRelSimpleQuery, setQueryKey, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface dragon.ir.query.Predicate

toSQLExpression, toString

Methods inherited from interface dragon.ir.query.IRQuery

getQueryKey, isRelBoolQuery, isRelSimpleQuery, setQueryKey

Field Detail

weight

protected double weight

predicateType

protected int predicateType

expressionType

protected int expressionType

constraint

protected Expression constraint

Constructor Detail

AbstractPredicate

public AbstractPredicate()

Method Detail

parse

public boolean parse(String predicate)

Specified by:

parse in interface IRQuery

Overrides:

parse in class AbstractIRQuery

Parameters:

predicate - the query string

Returns:

a structured query

getOperator

public Operator getOperator()

Specified by:

getOperator in interface IRQuery

Overrides:

getOperator in class AbstractIRQuery

isPredicate

public boolean isPredicate()

Description copied from interface: IRQuery

A predicate always begins with a ltter T (term predicate), R(relation predicate), or M(modifier predicate)

Specified by:

isPredicate in interface IRQuery

Overrides:

isPredicate in class AbstractIRQuery

Returns:

true if the the current query denotes a simple predicate, otherwise false.

isCompoundQuery

public boolean isCompoundQuery()

Description copied from interface: IRQuery

If the current query denotes a simple predicate, this method returns false, otherwise true.

Specified by:

isCompoundQuery in interface IRQuery

Overrides:

isCompoundQuery in class AbstractIRQuery

Returns:

false if the the current query denotes a simple predicate, otherwise true.

getChild

public IRQuery getChild(int index)

Specified by:

getChild in interface IRQuery

Overrides:

getChild in class AbstractIRQuery

getChildNum

public int getChildNum()

Specified by:

getChildNum in interface IRQuery

Overrides:

getChildNum in class AbstractIRQuery

getSelectivity

public double getSelectivity()

Specified by:

getSelectivity in interface IRQuery

Specified by:

getSelectivity in interface Predicate

Overrides:

getSelectivity in class AbstractIRQuery

Returns:

a double socre indicating how specific the query predicate is.

getWeight

public double getWeight()

Specified by:

getWeight in interface Predicate

setWeight

public void setWeight(double weight)

Specified by:

setWeight in interface Predicate

getConstraint

public Expression getConstraint()

Specified by:

getConstraint in interface Predicate

Returns:

the underlying expression of the current predicate

isSimplePredicate

public boolean isSimplePredicate()

Specified by:

isSimplePredicate in interface Predicate

isBoolPredicate

public boolean isBoolPredicate()

Specified by:

isBoolPredicate in interface Predicate

isTermPredicate

public boolean isTermPredicate()

Specified by:

isTermPredicate in interface Predicate

isRelationPredicate

public boolean isRelationPredicate()

Specified by:

isRelationPredicate in interface Predicate

isQualifierPredicate

public boolean isQualifierPredicate()

Specified by:

isQualifierPredicate in interface Predicate

parse

protected abstract void parse(String[] predicate)

Specified by:

parse in class AbstractIRQuery