/*******************************************************************************
* Copyright (c) 2004, 2007 IBM Corporation and Cambridge Semantics Incorporated.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* File: $Source: /cvsroot/slrp/glitter/com.ibm.adtech.glitter/src/com/ibm/adtech/glitter/query/PredicateSelectivityProvider.java,v $
* Created by: Lee Feigenbaum (<a href="mailto:feigenbl@us.ibm.com">feigenbl@us.ibm.com</a>)
* Created on: 10/23/06
* Revision: $Id: PredicateSelectivityProvider.java 164 2007-07-31 14:11:09Z mroy $
*
* Contributors: IBM Corporation - initial API and implementation
* Cambridge Semantics Incorporated - Fork to Anzo
*******************************************************************************/
package org.openanzo.glitter.query;
import org.openanzo.rdf.URI;
/**
* A {@link PredicateSelectivityProvider} defines selectivity values for a given predicate. A higher selectivity indicates that
* the predicate identifies a narrower set of subjects and objects. A predicate such as <tt>rdf:type</tt> has very low
* selectivity, for example.
*
* @author lee <lee@cambridgesemantics.com>
*
*/
public interface PredicateSelectivityProvider {
/**
* Get the (relative) selectivity for the given predicate
*
* @param predicate
* A value indicating the (relative) selectivity of the given predicate.
* @return the (relative) selectivity for the given predicate
*/
public abstract double getSelectivity(URI predicate);
}