JenaTextSparqlQueryFactory.java

package org.deri.grefine.reconcile.rdf.factories;

import java.util.ArrayList;
import java.util.List;

import org.apache.lucene.queryparser.classic.QueryParser;
import org.deri.grefine.reconcile.model.ReconciliationRequest;
import org.deri.grefine.reconcile.model.SearchResultItem;
import org.deri.grefine.reconcile.model.ReconciliationRequestContext.PropertyContext;
import org.deri.grefine.reconcile.util.StringUtils;
import org.json.JSONException;
import org.json.JSONWriter;

import com.google.common.collect.ImmutableList;
import com.hp.hpl.jena.query.QuerySolution;
import com.hp.hpl.jena.query.ResultSet;
import com.hp.hpl.jena.rdf.model.Literal;

/**
 * factories for queries understood by <a href="http://jena.sourceforge.net/ARQ/lucene-arq.html">LARQ</a>
 * notice that the queries use SPARQL 1.1 IN function so make sure you have a recent version of ARQ if you are using this class 
 * This class is not thread-safe. meant to be used once and die, do not try to save or reuse it is cheap to create
 * @author fadmaa
 *
 */
public class JenaTextSparqlQueryFactory extends AbstractSparqlQueryFactory{

	@Override
	public String getTypeSuggestSparqlQuery(String prefix, int limit) {
		return SUGGEST_TYPE_QUERY_TEMPLATE.replace("[[QUERY]]", escapeQuery(prefix)).replaceAll("\\[\\[LIMIT\\]\\]", String.valueOf(limit));
	}
	
	/**
	 * @param request
	 * @param searchPropertyUris
	 * @return sparql query according to the syntax expected by LARQ as described in their <a href="http://jena.sourceforge.net/ARQ/lucene-arq.html">documentation</a>. 
	 *   It is a standard SPARQL query apart form pf:textMatch used for full text search. <b>Note that this query uses <a href="http://www.w3.org/TR/2010/WD-sparql11-query-20101014/#func-in">IN function</a> which is only available in SPARQL 1.1</b>
	 */
	@Override
	public String getReconciliationSparqlQuery(ReconciliationRequest request, ImmutableList<String> searchPropertyUris) {
		//prepare type filter
		String typesFilter = "";
		if(request.getTypes().length>0){
			typesFilter = StringUtils.join(request.getTypes(), ">. } UNION ", "{?entity rdf:type <", " {", ">. }}");
		}
		//prepare context filter
		StringBuilder contextFilter = new StringBuilder();
		for(PropertyContext prop : request.getContext().getProperties()){
			contextFilter.append(PROPERTY_FILTER.replace("[[PROPERTY_URI]]", prop.getPid()).replace("[[VALUE]]", prop.getV().asSparqlValue()));
		}
		if(searchPropertyUris.size()==1){
			return getReconciliationSparqlQuery(SINGLE_LABEL_PROPERTY_RECONCILE_QUERY_TEMPLATE, searchPropertyUris, request.getQueryString(),typesFilter, contextFilter.toString(), "[[LABEL_PROPERTY_URI]]", searchPropertyUris.get(0), request.getLimit());
		}
		//prepare property URIs list (with || as separator)
		String labelFilter = StringUtils.join(searchPropertyUris, "> || ", "?p=<", "FILTER (", ">)");

		return getReconciliationSparqlQuery(RECONCILE_QUERY_TEMPLATE, searchPropertyUris, request.getQueryString(),typesFilter, contextFilter.toString(), "[[LABEL_PROPERTY_FILTER]]", labelFilter, request.getLimit());
	}	
	
	@Override
	public void write(JSONWriter writer) throws JSONException {
		writer.object();
		writer.key("type");	writer.value("larq");
		writer.endObject();
	}
	
	private String getReconciliationSparqlQuery(String queryTemplate, ImmutableList<String> searchPropertyUris, String query, String typesFilter, String contextFilter, String labelPlaceHolder, String labelFilter, int limit){
		String escapedQuery = escapeQuery(query);
		//the query returns a unique answer per (entity,label) pair. the *maximum* number of results is searchPropertyUris.size() * request.getLimit()
		//the answers are ordered according to their scores descendingly. thus we need to pick only the *first* request.getLimit() *unique* entity answer
		int calculatedLimit = Math.max(searchPropertyUris.size(),1) * limit;
		return queryTemplate.replace("[[QUERY]]", escapedQuery)
						.replace(labelPlaceHolder, labelFilter)
						.replace(labelPlaceHolder, labelFilter)
						.replace("[[TYPE_FILTER]]", typesFilter)
						.replace("[[CONTEXT_FILTER]]", contextFilter)
						.replace("[[LIMIT]]", String.valueOf(calculatedLimit))
						.replace("[[LIMIT]]", String.valueOf(calculatedLimit));
		
	}
	
	@Override
	public String getPropertySuggestSparqlQuery(String prefix, String typeUri, int limit) {
		return SUGGEST_PROPERTY_WITH_SPECIFIC_SUBJECT_TYPE_QUERY_TEMPLATE.replaceAll("\\[\\[QUERY\\]\\]", escapeQuery(prefix)).
										replaceAll("\\[\\[LIMIT\\]\\]", String.valueOf(limit))
										.replace("[[TYPE_URI]]", typeUri);
	}
	
	@Override
	public String getPropertySuggestSparqlQuery(String prefix, int limit) {
		return SUGGEST_PROPERTY_QUERY_TEMPLATE.replaceAll("\\[\\[QUERY\\]\\]", prefix).replaceAll("\\[\\[LIMIT\\]\\]", String.valueOf(limit));
	}
	
	@Override
	public String getSampleInstancesSparqlQuery(String typeUri, ImmutableList<String> searchPropertyUris, int limit) {
		return SAMPLE_INSTANCES_OF_TYPE_QUERY_TEMPLATE.replace("[[TYPE_URI]]", typeUri)
													.replace("[[PROPERTY_URI]]", searchPropertyUris.get(0))
													.replace("[[LIMIT]]", String.valueOf(limit));
	}

	
	@Override
	public ImmutableList<SearchResultItem> wrapTypeSuggestResultSet(ResultSet resultSet, String prefix, int limit) {
		List<SearchResultItem> result = new ArrayList<SearchResultItem>();
		while(resultSet.hasNext()){
			QuerySolution sol = resultSet.nextSolution();
			String pUri = sol.getResource("type").getURI();
			String label = getPreferredLabel(sol);
			result.add(new SearchResultItem(pUri, label));
		}
		return ImmutableList.copyOf(result);
	}

	@Override
	public ImmutableList<SearchResultItem> wrapPropertySuggestResultSet(ResultSet resultSet, String prefix, int limit) {
		List<SearchResultItem> result = new ArrayList<SearchResultItem>();
		while(resultSet.hasNext()){
			QuerySolution sol = resultSet.nextSolution();
			String pUri = sol.getResource("p").getURI();
			String label = getPreferredLabel(sol);
			result.add(new SearchResultItem(pUri, label));
		}
		return ImmutableList.copyOf(result);
	}

	@Override
	public String getEntitySearchSparqlQuery(String prefix, ImmutableList<String> searchPropertyUris, int limit) {
		//prepare property URIs list (with || as separator)
		String labelFilter = StringUtils.join(searchPropertyUris, "> || ", "?label_prop=<", "FILTER (", ">)");
		int calculatedLimit = searchPropertyUris.size() * limit;//because we want the maximum possible number
		return SEARCH_ENTITY_QUERY_TEMPLATE.replace("[[QUERY]]", escapeQuery(prefix))
											.replace("[[LABEL_PROPERTY_FILTER]]", labelFilter)
											.replace("[[LIMIT]]",String.valueOf(calculatedLimit))
											.replace("[[LIMIT]]",String.valueOf(calculatedLimit));
	}
	
	private String getPreferredLabel(QuerySolution sol){
		Literal s1 = sol.getLiteral("score1");
		Literal s2 = sol.getLiteral("score2");
		if(s1!=null){
			if(s2==null){
				return sol.getLiteral("label1").getString();
			}else{
				if(s1.getDouble()>s2.getDouble()){
					return sol.getLiteral("label1").getString();
				}else{
					return sol.getLiteral("label2").getString();
				}
			}
		}else if(s2!=null){
			return sol.getLiteral("label2").getString();
		}else{
			return "";
		}
	}

	private String escapeQuery(String q){
		String s = QueryParser.escape(q);
		return s.replaceAll("\\\\","\\\\\\\\").replaceAll("'", "\\\\'");
	}
	
	/**
	 * A (String, double) pair
	 * @author fadmaa
	 *
	 */
	protected static class ScoredLabel{
		final String label;
		final double score;
		public ScoredLabel(String label, double score) {
			this.label = label;
			this.score = score;
		}
		public double getScore() {
			return score;
		}
		
	}
	
	private static final String SUGGEST_TYPE_QUERY_TEMPLATE =
			"PREFIX text:<http://jena.apache.org/text#> " +
				"SELECT DISTINCT ?type ?label1 ?label2  " +
				"WHERE{" +
				"[] a ?type. " +
				"{" +
				"OPTIONAL {?type <http://www.w3.org/2000/01/rdf-schema#label> (?label1  '[[QUERY]]*' [[LIMIT]] ) . " +
				"?type <http://www.w3.org/2000/01/rdf-schema#label>  ?label1 . }" +
				"OPTIONAL {?type <http://www.w3.org/2004/02/skos/core#prefLabel> (?label2 '[[QUERY]]*' [[LIMIT]] )." +
				"?type <http://www.w3.org/2004/02/skos/core#prefLabel> ?label2.} " +
				"FILTER (bound(?label1) || bound(?label2))" +
				"}" +
				"} LIMIT [[LIMIT]]";
	
	private static final String SUGGEST_PROPERTY_WITH_SPECIFIC_SUBJECT_TYPE_QUERY_TEMPLATE =
				"PREFIX text:<http://jena.apache.org/text#> " +
				"SELECT DISTINCT ?p ?label1  ?label2 " +
				"WHERE{" +
				"[] a <[[TYPE_URI]]>; " +
				"?p ?v. " +
				"{" +
				"OPTIONAL {?p <http://www.w3.org/2000/01/rdf-schema#label> (?label1 '[[QUERY]]*' [[LIMIT]]). " +
				"?p <http://www.w3.org/2000/01/rdf-schema#label> ?label1. }" +
				"OPTIONAL {?p <http://www.w3.org/2004/02/skos/core#prefLabel> (?label2 '[[QUERY]]*' [[LIMIT]]). " +
				"?p <http://www.w3.org/2004/02/skos/core#prefLabel> ?label2. }" +
				"FILTER (bound(?label1) || bound(?label2))" +
				"}" +
				"} LIMIT [[LIMIT]]";
	
	private static final String SUGGEST_PROPERTY_QUERY_TEMPLATE =
		"PREFIX text:<http://jena.apache.org/text#> " +
		"SELECT DISTINCT ?p ?label1 ?label2 " +
		"WHERE{" +
		"[] ?p ?v. " +
		"{" +
		"OPTIONAL {?p <http://www.w3.org/2000/01/rdf-schema#label> (?label1 '[[QUERY]]*'  [[LIMIT]]). " +
		"?p <http://www.w3.org/2000/01/rdf-schema#label> ?label1. }" +
		"OPTIONAL {?p <http://www.w3.org/2004/02/skos/core#prefLabel> (?label2 '[[QUERY]]*' [[LIMIT]]). " +
		"?p <http://www.w3.org/2004/02/skos/core#prefLabel> ?label2. }" +
		"FILTER (bound(?label1) || bound(?label2))" +
		"}" +
		"} LIMIT [[LIMIT]]";
	
	private static final String RECONCILE_QUERY_TEMPLATE =
				"PREFIX rdfs:<http://www.w3.org/2000/01/rdf-schema#> " + 
				"PREFIX text:<http://jena.apache.org/text#> " +
				"PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#> "+  
				"SELECT ?entity ?label " +
				"WHERE" +
				"{" +
					"?entity ?p (?label '[[QUERY]]' [[LIMIT]])." +
					"?entity ?p ?label." +
					"[[LABEL_PROPERTY_FILTER]]" +
					"[[TYPE_FILTER]]" +
					"[[CONTEXT_FILTER]]" +
				" FILTER (isIRI(?entity))}GROUP BY ?entity ?label " +
				"LIMIT [[LIMIT]]";
	private static final String SINGLE_LABEL_PROPERTY_RECONCILE_QUERY_TEMPLATE =
		"PREFIX rdfs:<http://www.w3.org/2000/01/rdf-schema#> " + 
		"PREFIX text:<http://jena.apache.org/text#> " +
		"PREFIX rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#> "+  
		"SELECT ?entity ?label " +
		"WHERE " +
		"{ " +
			"?entity text:query (<[[LABEL_PROPERTY_URI]]> '[[QUERY]]' [[LIMIT]]) . " +
			"?entity <[[LABEL_PROPERTY_URI]]> ?label ." +
			"[[TYPE_FILTER]]" +
			"[[CONTEXT_FILTER]]" +
		"}GROUP BY ?entity ?label " +
		"ORDER BY DESC(?score1) LIMIT [[LIMIT]]";
	private static final String PROPERTY_FILTER = "?entity <[[PROPERTY_URI]]> [[VALUE]]. ";
	
	private static final String SAMPLE_INSTANCES_OF_TYPE_QUERY_TEMPLATE = 
			"SELECT ?entity (SAMPLE(?label) AS ?label1) " +
			"WHERE{" +
			"?entity a <[[TYPE_URI]]>. " +
			"?entity <[[PROPERTY_URI]]> ?label." +
			"}GROUP BY ?entity LIMIT [[LIMIT]]";
	
	private static final String SEARCH_ENTITY_QUERY_TEMPLATE =
			"PREFIX text:<http://jena.apache.org/text#> " +
			"SELECT ?entity ?label " +
			"WHERE{" +
			"?entity ?label_prop (?label '[[QUERY]]*' [[LIMIT]]) . " +
			"?entity ?label_prop ?label . " +
			"[[LABEL_PROPERTY_FILTER]]. " +
			"} LIMIT [[LIMIT]]";
}