René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Infinite loop while framing data","articleBody":"With the following test case and the serialized data [model-ser.zip](https://github.com/jsonld-java/jsonld-java/files/11397861/model-ser.zip) (you need to unzip and change the path to the file). When running test case we run into an infinite loop. I think something needs to be done to handle this problem because you never know what data is going to be loaded.\r\n\r\n```\r\n    @Test\r\n    public void testJsonLdCycle() throws Exception {\r\n        final JsonLdOptions opts = new JsonLdOptions();\r\n\r\n        //opts.setUseRdfType(getWriterConfig().get(JSONLDSettings.USE_RDF_TYPE));\r\n        opts.setUseNativeTypes(true);\r\n        opts.setCompactArrays(true);\r\n        //opts.setOmitGraph(getWriterConfig().get(OMIT_GRAPH));\r\n        opts.setEmbed(Embed.ALWAYS);\r\n\r\n        String testFrame = \"{\\\"@context\\\" : [ \\\"http://cambridgesemantics.com/ontologies/GraphmartStatus/LayerStatus\\\", \\\"http://cambridgesemantics.com/ontologies/GraphmartStatus/LayerChildStatus\\\", \\\"http://www.w3.org/2002/07/owl/Thing\\\", \\\"http://cambridgesemantics.com/ontologies/GraphmartStatus/GraphmartStatus\\\" ], \\\"@type\\\" : [ \\\"http://cambridgesemantics.com/ontologies/GraphmartStatus#GraphmartStatus\\\" ]}\";\r\n\r\n        final SesameRDFParser serialiser = new SesameRDFParser();\r\n\r\n        try (ObjectInputStream in = new ObjectInputStream(new UserDirFileInputStream(\"/test/resources/coredata/model.ser\"))) {\r\n            Model model = (LinkedHashModel) in.readObject();\r\n\r\n            Object output = JsonLdProcessor.fromRDF(model, opts, serialiser);\r\n            JsonLdProcessor.frame(output, JsonUtils.fromString(testFrame), opts);\r\n        }\r\n\r\n    }\r\n\r\n    public class SesameRDFParser implements com.github.jsonldjava.core.RDFParser {\r\n\r\n        public void setPrefix(RDFDataset result, String fullUri, String prefix) {\r\n            result.setNamespace(fullUri, prefix);\r\n        }\r\n\r\n        public void handleStatement(RDFDataset result, org.openrdf.model.Statement nextStatement) {\r\n            // TODO: from a basic look at the code it seems some of these could be\r\n            // null\r\n            // null values for IRIs will probably break things further down the line\r\n            // and i'm not sure yet if this should be something handled later on, or\r\n            // something that should be checked here\r\n            final String subject = getResourceValue(nextStatement.getSubject());\r\n            final String predicate = getResourceValue(nextStatement.getPredicate());\r\n            final Value object = nextStatement.getObject();\r\n            final String graphName = getResourceValue(nextStatement.getContext());\r\n\r\n            if (object instanceof Literal) {\r\n                final Literal literal = (Literal) object;\r\n                final String value = literal.getLabel();\r\n                final String language = literal.getLanguage();\r\n\r\n                String datatype = getResourceValue(literal.getDatatype());\r\n\r\n                // In RDF-1.1, Language Literals internally have the datatype\r\n                // rdf:langString\r\n                if (language != null \u0026\u0026 datatype == null) {\r\n                    datatype = org.openrdf.model.vocabulary.RDF.LANGSTRING.stringValue();\r\n                }\r\n\r\n                // In RDF-1.1, RDF-1.0 Plain Literals are now Typed Literals with\r\n                // type xsd:String\r\n                if (language == null \u0026\u0026 datatype == null) {\r\n                    datatype = XMLSchema.STRING.stringValue();\r\n                }\r\n\r\n                result.addQuad(subject, predicate, value, datatype, language, graphName);\r\n\r\n            } else {\r\n                result.addQuad(subject, predicate, getResourceValue((Resource) object), graphName);\r\n            }\r\n        }\r\n\r\n        private String getResourceValue(Resource subject) {\r\n            if (subject == null) {\r\n                return null;\r\n            } else if (subject instanceof URI) {\r\n                return subject.stringValue();\r\n            } else if (subject instanceof BNode) {\r\n                return \"_:\" + subject.stringValue();\r\n            }\r\n\r\n            throw new IllegalStateException(\"Did not recognise resource type: \" + subject.getClass().getName());\r\n        }\r\n\r\n        @Override\r\n        public RDFDataset parse(Object input) throws JsonLdError {\r\n            final RDFDataset result = new RDFDataset();\r\n            if (input instanceof Statement) {\r\n                handleStatement(result, (Statement) input);\r\n            } else if (input instanceof Graph) {\r\n                if (input instanceof Model) {\r\n                    final Set\u003cNamespace\u003e namespaces = ((Model) input).getNamespaces();\r\n                    for (final Namespace nextNs : namespaces) {\r\n                        result.setNamespace(nextNs.getName(), nextNs.getPrefix());\r\n                    }\r\n                }\r\n\r\n                for (final org.openrdf.model.Statement nextStatement : (Graph) input) {\r\n                    handleStatement(result, nextStatement);\r\n                }\r\n            }\r\n            return result;\r\n        }\r\n\r\n    }\r\n```","author":{"url":"https://github.com/garpinc","@type":"Person","name":"garpinc"},"datePublished":"2023-05-04T13:19:11.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":3},"url":"https://github.com/338/jsonld-java/issues/338"}