添加含sh:targetNode与sh:minCount>0的SHACL规则时RDF4J抛出验证异常

在使用RDF4J的SailRepositoryConnection时，添加包含sh:targetNode且sh:minCount>0的SHACL规则后，调用connection.commit()会抛出ShaclSailValidationException。但如果不设置sh:minCount或将其值设为0，该异常就不会出现。请问这是什么原因导致的？

异常信息 #

org.eclipse.rdf4j.sail.shacl.ShaclSailValidationException: Failed SHACL validation
org.eclipse.rdf4j.repository.RepositoryException: org.eclipse.rdf4j.sail.shacl.ShaclSailValidationException: Failed SHACL validation
    at org.eclipse.rdf4j.repository.sail.SailRepositoryConnection.commit(SailRepositoryConnection.java:228)
    at ch.unisg.ics.interactions.hmas.interaction.validation.ShaclValidationTest.testContextValidationRDF4j(ShaclValidationTest.java:178)
    at java.base/java.lang.reflect.Method.invoke(Method.java:580)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)
    at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)
Caused by: org.eclipse.rdf4j.sail.shacl.ShaclSailValidationException: Failed SHACL validation
    at org.eclipse.rdf4j.sail.shacl.ShaclSailConnection.prepare(ShaclSailConnection.java:892)
    at org.eclipse.rdf4j.repository.sail.SailRepositoryConnection.commit(SailRepositoryConnection.java:225)

代码示例 #

String shaclRules = "@prefix sh: <http://www.w3.org/ns/shacl#> .\n" +
        "@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .\n\n" +
        "<http://example.org/component/component-state-context>\n" +
        "                       a sh:PropertyShape;\n" +
        "                       sh:targetNode <http://example.org/component>;\n" +
        "                       sh:path <https://saref.etsi.org/core/hasState>;\n" +
        "                       sh:maxCount 1;\n" +
        "                       sh:minCount 1." ;

ShaclSail shaclSail = new ShaclSail(new MemoryStore());

SailRepository sailRepository = new SailRepository(shaclSail);
sailRepository.init();

try (SailRepositoryConnection connection = sailRepository.getConnection()) {
  connection.begin();
  connection.add(new StringReader(shaclRules), "", RDFFormat.TURTLE, RDF4J.SHACL_SHAPE_GRAPH);
  connection.commit();
}

核心原因 #

RDF4J的ShaclSail默认会在提交操作时对仓库内所有数据执行SHACL校验。你定义的规则明确要求<http://example.org/component>节点必须至少拥有一个hasState属性，但此时仓库中完全没有该节点的hasState相关数据，直接触发了minCount=1的校验失败，进而抛出异常。

当sh:minCount设为0或不设置时，规则允许目标节点缺失hasState属性，自然不会触发校验失败，commit就能正常完成。

解决办法 #

1. 调整操作顺序，先加数据再加规则 #

先将符合规则的目标节点数据存入仓库，再添加SHACL规则，确保校验时数据满足要求：

try (SailRepositoryConnection connection = sailRepository.getConnection()) {
  connection.begin();
  // 先添加目标节点的hasState数据
  String componentData = "@prefix saref: <https://saref.etsi.org/core/> .\n" +
          "<http://example.org/component> saref:hasState <http://example.org/state/active> .";
  connection.add(new StringReader(componentData), "", RDFFormat.TURTLE);
  // 再添加SHACL规则
  connection.add(new StringReader(shaclRules), "", RDFFormat.TURTLE, RDF4J.SHACL_SHAPE_GRAPH);
  connection.commit();
}

2. 临时关闭校验后添加规则 #

初始化ShaclSail时关闭自动校验，添加完规则后再开启：

ShaclSail shaclSail = new ShaclSail(new MemoryStore())
    .withValidationEnabled(false);

SailRepository sailRepository = new SailRepository(shaclSail);
sailRepository.init();

try (SailRepositoryConnection connection = sailRepository.getConnection()) {
  connection.begin();
  connection.add(new StringReader(shaclRules), "", RDFFormat.TURTLE, RDF4J.SHACL_SHAPE_GRAPH);
  connection.commit();
  
  // 添加完规则后重新开启校验
  shaclSail.setValidationEnabled(true);
}

3. 用sh:deactivated临时禁用规则 #

在添加规则时先标记为禁用，后续需要生效时再移除该标记：

String shaclRules = "@prefix sh: <http://www.w3.org/ns/shacl#> .\n" +
        "@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .\n\n" +
        "<http://example.org/component/component-state-context>\n" +
        "                       a sh:PropertyShape;\n" +
        "                       sh:deactivated true;\n" +
        "                       sh:targetNode <http://example.org/component>;\n" +
        "                       sh:path <https://saref.etsi.org/core/hasState>;\n" +
        "                       sh:maxCount 1;\n" +
        "                       sh:minCount 1." ;

内容的提问来源于stack exchange，提问作者stln