GH-5151: use VALUES clause for FedX bind join with no free vars (#5165)

Author: hmottestad

tools/federation/src/main/java/org/eclipse/rdf4j/federated/evaluation/FederationEvalStrategy.java

@@ -935,7 +935,10 @@ public abstract CloseableIteration<BindingSet> evaluateBoundJoinStatementPattern
 	 * @param bindings
 	 * @return the result iteration
 	 * @throws QueryEvaluationException
+	 * @deprecated with VALUES implementation, control flow goes via
+	 *             {@link #evaluateBoundJoinStatementPattern(StatementTupleExpr, List)}
 	 */
+	@Deprecated(forRemoval = true)
 	public abstract CloseableIteration<BindingSet> evaluateGroupedCheck(
 			CheckStatementPattern stmt, final List<BindingSet> bindings) throws QueryEvaluationException;
 

tools/federation/src/main/java/org/eclipse/rdf4j/federated/evaluation/SparqlFederationEvalStrategy.java

@@ -118,8 +118,9 @@ public CloseableIteration<BindingSet> evaluateBoundJoinStatementPattern(
 	/**
 	 * Alternative evaluation implementation using UNION. Nowadays we use a VALUES clause based implementation
 	 *
-	 * @deprecated
+	 * @deprecated no longer used
 	 */
+	@Deprecated(forRemoval = true)
 	protected CloseableIteration<BindingSet> evaluateBoundJoinStatementPattern_UNION(
 			StatementTupleExpr stmt, List<BindingSet> bindings)
 			throws QueryEvaluationException {

tools/federation/src/main/java/org/eclipse/rdf4j/federated/evaluation/join/ControlledWorkerBindJoin.java

@@ -45,12 +45,7 @@ protected TaskCreator determineTaskCreator(TupleExpr expr, BindingSet bs) {
 		final TaskCreator taskCreator;
 		if (expr instanceof StatementTupleExpr) {
 			StatementTupleExpr stmt = (StatementTupleExpr) expr;
-			if (stmt.hasFreeVarsFor(bs)) {
-				taskCreator = new BoundJoinTaskCreator(strategy, stmt);
-			} else {
-				expr = new CheckStatementPattern(stmt, queryInfo);
-				taskCreator = new CheckJoinTaskCreator(strategy, (CheckStatementPattern) expr);
-			}
+			taskCreator = new BoundJoinTaskCreator(strategy, stmt);
 		} else if (expr instanceof FedXService) {
 			taskCreator = new FedXServiceJoinTaskCreator(strategy, (FedXService) expr);
 		} else {
@@ -77,6 +72,7 @@ public ParallelTask<BindingSet> getTask(ParallelExecutor<BindingSet> control, Li
 		}
 	}
 
+	@Deprecated(forRemoval = true)
 	protected class CheckJoinTaskCreator implements TaskCreator {
 		protected final FederationEvalStrategy _strategy;
 		protected final CheckStatementPattern _expr;

tools/federation/src/main/java/org/eclipse/rdf4j/federated/evaluation/join/ParallelCheckJoinTask.java

@@ -24,7 +24,9 @@
  * {@link FederationEvalStrategy#evaluateGroupedCheck(CheckStatementPattern, List)} for further details.
  *
  * @author Andreas Schwarte
+ * @deprecated now integrated in {@link ParallelBoundJoinTask} (with VALUES clause)
  */
+@Deprecated(forRemoval = true)
 public class ParallelCheckJoinTask extends ParallelTaskBase<BindingSet> {
 
 	protected final FederationEvalStrategy strategy;

tools/federation/src/test/java/org/eclipse/rdf4j/federated/BoundJoinTests.java

@@ -45,4 +45,12 @@ public void testBoundJoin_FailingEndpoint() throws Exception {
 			execute("/tests/boundjoin/query01.rq", "/tests/boundjoin/query01.srx", false, true);
 		});
 	}
+
+	@Test
+	public void testBoundCheck() throws Exception {
+
+		/* test with VALUES clause based bound join, check join */
+		prepareTest(Arrays.asList("/tests/data/data1.ttl", "/tests/data/data2.ttl"));
+		execute("/tests/boundjoin/query02_checkJoin.rq", "/tests/boundjoin/query02_checkJoin.srx", false, true);
+	}
 }

tools/federation/src/test/resources/tests/boundjoin/query02_checkJoin.rq

@@ -0,0 +1,10 @@
+# bound join query (where in the bind join all variables are bound)
+PREFIX ns1: <http://namespace1.org/>
+PREFIX foaf: <http://xmlns.com/foaf/0.1/>
+PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
+PREFIX owl:  <http://www.w3.org/2002/07/owl#>
+
+SELECT ?person ?name WHERE {
+ ?person rdf:type foaf:Person .
+ ?person foaf:age 25 .
+}

tools/federation/src/test/resources/tests/boundjoin/query02_checkJoin.srx

@@ -0,0 +1,20 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<sparql xmlns='http://www.w3.org/2005/sparql-results#'>
+	<head>
+		<variable name='person'/>
+		<variable name='name'/>
+		<variable name='publication'/>
+	</head>
+	<results>
+		<result>
+			<binding name='person'>
+				<uri>http://namespace1.org/Person_4</uri>
+			</binding>
+		</result>
+		<result>
+			<binding name='person'>
+				<uri>http://namespace2.org/Person_6</uri>
+			</binding>
+		</result>
+	</results>
+</sparql>

tools/federation/src/test/resources/tests/data/data1.ttl

@@ -24,6 +24,7 @@
 :Person_4 rdf:type foaf:Person .
 :Person_4 rdf:type :Person .
 :Person_4 foaf:name "Person4" .
+:Person_4 foaf:age "25"^^xsd:integer .
 
 :Person_5 rdf:type foaf:Person .
 :Person_5 rdf:type :Person .

tools/federation/src/test/resources/tests/data/data2.ttl

@@ -9,7 +9,7 @@
 :Person_6 rdf:type foaf:Person .
 :Person_6 rdf:type :Person .
 :Person_6 foaf:name "Person6" .
-:Person_1 foaf:age "25"^^xsd:integer .
+:Person_6 foaf:age "25"^^xsd:integer .
 
 :Person_7 rdf:type foaf:Person .
 :Person_7 rdf:type :Person .