Executor: fix crash when subject has null

XPath expresssions may return null in subjects, do not crash then. Fixes #236
RMLio · Jun 10, 2024 · 144f9b4 · 144f9b4
1 parent fd59a3e
commit 144f9b4
Show file tree

Hide file tree

Showing 7 changed files with 128 additions and 3 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -10,6 +10,9 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Added
 - Serialization format TriG is now supported for Logical Targets (fixes GitHub [issue 225](https://github.com/RMLio/rmlmapper-java/issues/225)).
 
+### Fixed
+- Crash when null is returned in an XPath function for subject generation (fixes GitHub [issue 236](https://github.com/RMLio/rmlmapper-java/issues/236))
+
 ## [7.0.0] - 2024-06-07
 
 ### Fixed
@@ -114,8 +117,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Update dependency to `idlab-functions-java`, fixing [issue #218](https://github.com/RMLio/rmlmapper-java/issues/218) 
 
 ### Changed
-<<<<<<< HEAD
-- Dockefile: switched to Eclipse OpenJDK Docker base image because OpenJDK is deprecated
+- Dockerfile: switched to Eclipse OpenJDK Docker base image because OpenJDK is deprecated
 - CI: dropped GitHub release automation
 - CI: verify if token is valid
 

diff --git a/src/main/java/be/ugent/rml/Executor.java b/src/main/java/be/ugent/rml/Executor.java
@@ -299,7 +299,8 @@ private List<ProvenancedTerm> getIRIsWithTrueCondition(Record child, Term triple
 
             if (Boolean.TRUE.equals(expectedBoolean)) {
                 List<ProvenancedTerm> subjects = this.getSubject(triplesMap, mapping, parent, i);
-                iris.addAll(subjects);
+                if (subjects != null)
+                    iris.addAll(subjects);
             } else {
                 logger.warn("The used condition with the Parent Triples Map does not return a boolean.");
             }

diff --git a/src/test/java/be/ugent/rml/MapperXMLTest.java b/src/test/java/be/ugent/rml/MapperXMLTest.java
@@ -232,4 +232,9 @@ public void evaluate_1033_XML() {
     public void evaluate_1034_XML() {
         doMapping("./test-cases/RMLTC1034-XML/mapping.ttl", "./test-cases/RMLTC1034-XML/output.nq");
     }
+
+    @Test
+    public void evaluate_1035_XML() {
+        doMapping("./test-cases/RMLTC1035-XML/mapping.ttl", "./test-cases/RMLTC1035-XML/output.nq");
+    }
 }
diff --git a/src/test/resources/test-cases/RMLTC1035-XML/data.xml b/src/test/resources/test-cases/RMLTC1035-XML/data.xml
@@ -0,0 +1,19 @@
+<?xml version="1.0"?>
+<railML xmlns="https://www.railml.org/schemas/3.1">
+    <netElements>
+        <netElement id="A" x="1" y="3">
+            <name language="NO" name="NODE-1"/>
+            <relation ref="A_B"/>
+        </netElement>
+        <netElement id="B" x="6" y="8">
+            <name language="NO" name="NODE-2"/>
+            <relation ref="A_B"/>
+        </netElement>
+    </netElements>
+    <netRelations>
+        <netRelation id="A_B">
+            <elementA ref="A"/>
+            <elementB ref="B"/>
+        </netRelation>
+    </netRelations>
+</railML>
diff --git a/src/test/resources/test-cases/RMLTC1035-XML/mapping.ttl b/src/test/resources/test-cases/RMLTC1035-XML/mapping.ttl
@@ -0,0 +1,63 @@
+@prefix owl: <http://www.w3.org/2002/07/owl#> .
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+@prefix rr: <http://www.w3.org/ns/r2rml#> .
+@prefix rml: <http://semweb.mmlab.be/ns/rml#> .
+@prefix ql: <http://semweb.mmlab.be/ns/ql#> .
+@prefix ex: <http://data.example.org/resource/> .
+@prefix org: <http://www.w3.org/ns/org#> .
+@prefix skos: <http://www.w3.org/2004/02/skos/core#> .
+@prefix fnml:   <http://semweb.mmlab.be/ns/fnml#> .
+@prefix fno: <https://w3id.org/function/ontology#> .
+@prefix idlab-fn: <http://example.com/idlab/function/> .
+
+ex:Organizations a rr:TriplesMap;
+    rml:logicalSource [
+        rml:source "test.xml";
+        rml:iterator "/Directory/Organization";
+        rml:referenceFormulation ql:XPath
+    ];
+    rr:subjectMap [
+        rr:template "http://data.example.org/resource/Organization_{ID}";
+        rr:class org:Organization
+    ];
+    rr:predicateObjectMap [
+        rr:predicate org:name;
+        rr:objectMap
+            [
+                rml:reference "Name"
+            ];
+    ] ;
+    rr:predicateObjectMap [
+        rr:predicate org:address;
+        rr:objectMap
+            [
+                rr:parentTriplesMap ex:Addresses ;
+                rr:joinCondition [
+                    rr:child "path(.)";
+                    rr:parent "path(..)";
+                ];
+            ];
+    ]
+.
+
+ex:Addresses a rr:TriplesMap;
+    rml:logicalSource [
+        rml:source "test.xml";
+        rml:iterator "/Directory/Organization/Address";
+        rml:referenceFormulation ql:XPath
+    ];
+    rr:subjectMap [
+        # rr:template "http://data.example.org/resource/Address_{generate-id(.)}";
+        rml:reference "if(exists(StreetName)) then 'http://data.example.org/resource/Address_' || generate-id(.) else null";
+        rr:class org:Address
+    ];
+    rr:predicateObjectMap [
+        rr:predicate org:streetName;
+        rr:objectMap
+            [
+                rml:reference "StreetName"
+            ];
+    ] ;
+.
diff --git a/src/test/resources/test-cases/RMLTC1035-XML/output.nq b/src/test/resources/test-cases/RMLTC1035-XML/output.nq
@@ -0,0 +1,12 @@
+<http://data.example.org/resource/Address_d0e33> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/ns/org#Address> .
+<http://data.example.org/resource/Address_d0e33> <http://www.w3.org/ns/org#streetName> "99 Maine St" .
+<http://data.example.org/resource/Address_d0e9> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/ns/org#Address> .
+<http://data.example.org/resource/Address_d0e9> <http://www.w3.org/ns/org#streetName> "ABC FastCo Lane" .
+<http://data.example.org/resource/Organization_123> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/ns/org#Organization> .
+<http://data.example.org/resource/Organization_123> <http://www.w3.org/ns/org#address> <http://data.example.org/resource/Address_d0e9> .
+<http://data.example.org/resource/Organization_123> <http://www.w3.org/ns/org#name> "ABC FastCo" .
+<http://data.example.org/resource/Organization_456> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/ns/org#Organization> .
+<http://data.example.org/resource/Organization_456> <http://www.w3.org/ns/org#name> "XYZ Inc." .
+<http://data.example.org/resource/Organization_789> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/ns/org#Organization> .
+<http://data.example.org/resource/Organization_789> <http://www.w3.org/ns/org#address> <http://data.example.org/resource/Address_d0e33> .
+<http://data.example.org/resource/Organization_789> <http://www.w3.org/ns/org#name> "MNO Ltd" .
diff --git a/src/test/resources/test-cases/RMLTC1035-XML/test.xml b/src/test/resources/test-cases/RMLTC1035-XML/test.xml
@@ -0,0 +1,23 @@
+<Directory>
+	<Organization>
+		<ID>123</ID>
+		<Name>ABC FastCo</Name>
+		<Address>
+			<StreetName>ABC FastCo Lane</StreetName>
+		</Address>
+	</Organization>
+	<Organization>
+		<ID>456</ID>
+		<Name>XYZ Inc.</Name>
+		<Address>
+			<Area>XYZ Metro</Area>
+		</Address>
+	</Organization>
+	<Organization>
+		<ID>789</ID>
+		<Name>MNO Ltd</Name>
+		<Address>
+			<StreetName>99 Maine St</StreetName>
+		</Address>
+	</Organization>
+</Directory>