dragon.ir.query
Interface Predicate

All Superinterfaces:

IRQuery

All Known Implementing Classes:

AbstractPredicate

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

static int	PREDICATE_BOOL
static int	PREDICATE_QUALIFIER
static int	PREDICATE_RELATION
static int	PREDICATE_SIMPLE
static int	PREDICATE_TERM

Method Summary

Expression	getConstraint()
double	getSelectivity()
double	getWeight()
boolean	isBoolPredicate()
boolean	isQualifierPredicate()
boolean	isRelationPredicate()
boolean	isSimplePredicate()
boolean	isTermPredicate()
void	setWeight(double weight)
java.lang.String	toSQLExpression()
java.lang.String	toString()

Methods inherited from interface dragon.ir.query.IRQuery

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

Field Detail

PREDICATE_TERM

public static final int PREDICATE_TERM

See Also:

Constant Field Values

PREDICATE_RELATION

public static final int PREDICATE_RELATION

See Also:

Constant Field Values

PREDICATE_QUALIFIER

public static final int PREDICATE_QUALIFIER

See Also:

Constant Field Values

PREDICATE_SIMPLE

public static final int PREDICATE_SIMPLE

See Also:

Constant Field Values

PREDICATE_BOOL

public static final int PREDICATE_BOOL

See Also:

Constant Field Values

Method Detail

getSelectivity

public double getSelectivity()

Specified by:

getSelectivity in interface IRQuery

Returns:

a double socre indicating how specific the query predicate is.

getWeight

public double getWeight()

setWeight

public void setWeight(double weight)

isSimplePredicate

public boolean isSimplePredicate()

isBoolPredicate

public boolean isBoolPredicate()

isTermPredicate

public boolean isTermPredicate()

isRelationPredicate

public boolean isRelationPredicate()

isQualifierPredicate

public boolean isQualifierPredicate()

getConstraint

public Expression getConstraint()

Returns:

the underlying expression of the current predicate

toSQLExpression

public java.lang.String toSQLExpression()

toString

public java.lang.String toString()

Specified by:

toString in interface IRQuery

Overrides:

toString in class java.lang.Object