SparqlViewMatcherProjectionUtils.java

package org.aksw.jena_sparql_api.view_matcher;

import java.util.Map;
import java.util.Set;

import org.aksw.jena_sparql_api.concept_cache.core.SetUtils;
import org.aksw.jena_sparql_api.concept_cache.core.VarInfo;
import org.aksw.jena_sparql_api.concept_cache.core.VarUsage;
import org.apache.jena.sparql.core.Var;

import com.google.common.collect.Sets;

public class SparqlViewMatcherProjectionUtils {
	public static boolean validateProjection(VarInfo viewVarInfo, VarInfo userVarInfo, Map<Var, Var> varMap) {
		Set<Var> mappedViewVars = SetUtils.mapSet(viewVarInfo.getProjectVars(), varMap);
		mappedViewVars.remove(null);

		Set<Var> userVars = userVarInfo.getProjectVars();
		boolean result = mappedViewVars.containsAll(userVars);

//		if(result) {
//			// We passed the first check, now examine distinct vars
//			if(viewVarInfo.getDistinctLevel() > 0) {
//				// Make sure there is no overlap with non-unique vars
//				result = Sets.intersection(mappedViewVars, queryVarUsage.getNonUnique()).isEmpty();
////
////				if(result) {
////					// TODO Any more conditions? such as required distinct variables?
////				}
//
//				// Now check the distinct vars
////				Set<Var> mappedDistinctViewVars = SetUtils.mapSet(view.getDistinctVars(), varMap);
////				mappedDistinctViewVars.remove(null);
//			}
//		}

		return result;
	}



	/**
	 * Returns true if the view vars described in VarInfo fit the queries var requirements expressed in VarUsage under a given varMap
	 *
	 * Conditions
	 * (1) The mapped view variables must be a super set of the mandatory query variables
	 * (2) The set of mapped distinct view variables must also be distinct in the query
	 * The query's distinct vars must be
	 *     (i.e: we cannot un-distinct view variables, hence the query must accept them as they are)
	 *
	 *
	 * @param viewVarInfo
	 * @param queryVarUsage
	 * @param varMap
	 * @return
	 */
	public static boolean validateProjection(VarInfo viewVarInfo, VarUsage queryVarUsage, Map<Var, Var> varMap) {
		Set<Var> mappedViewVars = SetUtils.mapSet(viewVarInfo.getProjectVars(), varMap);
		mappedViewVars.remove(null);

		Set<Var> mandatoryVars = VarUsage.getMandatoryVars(queryVarUsage);

		boolean result = mappedViewVars.containsAll(mandatoryVars);

		if(result) {
			// We passed the first check, now examine distinct vars
			if(viewVarInfo.getDistinctLevel() > 0) {
				// Make sure there is no overlap with non-unique vars
				result = Sets.intersection(mappedViewVars, queryVarUsage.getNonUnique()).isEmpty();
//
//				if(result) {
//					// TODO Any more conditions? such as required distinct variables?
//				}

				// Now check the distinct vars
//				Set<Var> mappedDistinctViewVars = SetUtils.mapSet(view.getDistinctVars(), varMap);
//				mappedDistinctViewVars.remove(null);
			}
		}

		return result;
	}
}