/* * (non-Javadoc) * @see org.springframework.hateoas.hal.CurieProvider#getNamespacedRelFrom(java.lang.String) */ @Override public String getNamespacedRelFor(String rel) { boolean prefixingNeeded = defaultCurie != null && !IanaRels.isIanaRel(rel) && !rel.contains(":"); return prefixingNeeded ? String.format("%s:%s", defaultCurie.name, rel) : rel; }
@Override public void serialize(List<Link> links, JsonGenerator jgen, SerializerProvider serializerProvider) throws IOException { try { Collection<Link> simpleLinks = new ArrayList<Link>(); Collection<Affordance> affordances = new ArrayList<Affordance>(); Collection<Link> templatedLinks = new ArrayList<Link>(); Collection<Affordance> templatedAffordances = new ArrayList<Affordance>(); Collection<Affordance> collectionAffordances = new ArrayList<Affordance>(); Link selfRel = null; for (Link link : links) { if (link instanceof Affordance) { final Affordance affordance = (Affordance) link; final List<ActionDescriptor> actionDescriptors = affordance.getActionDescriptors(); if (!actionDescriptors.isEmpty()) { if (affordance.isTemplated()) { templatedAffordances.add(affordance); } else { if (!affordance.isSelfRel() && Cardinality.COLLECTION == affordance.getCardinality()) { collectionAffordances.add(affordance); } else { affordances.add(affordance); } } } else { if (affordance.isTemplated()) { templatedLinks.add(affordance); } else { simpleLinks.add(affordance); } } } else if (link.isTemplated()) { templatedLinks.add(link); } else { simpleLinks.add(link); } if ("self".equals(link.getRel())) { selfRel = link; } } for (Affordance templatedAffordance : templatedAffordances) { jgen.writeObjectFieldStart(templatedAffordance.getRel()); jgen.writeStringField("@type", "hydra:IriTemplate"); jgen.writeStringField("hydra:template", templatedAffordance.getHref()); final List<ActionDescriptor> actionDescriptors = templatedAffordance.getActionDescriptors(); ActionDescriptor actionDescriptor = actionDescriptors.get(0); jgen.writeArrayFieldStart("hydra:mapping"); writeHydraVariableMapping(jgen, actionDescriptor, actionDescriptor.getPathVariableNames()); writeHydraVariableMapping(jgen, actionDescriptor, actionDescriptor.getRequestParamNames()); jgen.writeEndArray(); jgen.writeEndObject(); } for (Link templatedLink : templatedLinks) { // we only have the template, no access to method params jgen.writeObjectFieldStart(templatedLink.getRel()); jgen.writeStringField("@type", "hydra:IriTemplate"); jgen.writeStringField("hydra:template", templatedLink.getHref()); jgen.writeArrayFieldStart("hydra:mapping"); writeHydraVariableMapping(jgen, null, templatedLink.getVariableNames()); jgen.writeEndArray(); jgen.writeEndObject(); } @SuppressWarnings("unchecked") Deque<LdContext> contextStack = (Deque<LdContext>) serializerProvider.getAttribute(JacksonHydraSerializer.KEY_LD_CONTEXT); String currentVocab = (contextStack != null && !contextStack.isEmpty()) ? contextStack.peek().vocab : null; // related collections if (!collectionAffordances.isEmpty()) { jgen.writeArrayFieldStart("hydra:collection"); for (Affordance collectionAffordance : collectionAffordances) { jgen.writeStartObject(); jgen.writeStringField(JsonLdKeywords.AT_TYPE, "hydra:Collection"); jgen.writeStringField(JsonLdKeywords.AT_ID, collectionAffordance.getHref()); jgen.writeObjectFieldStart("hydra:manages"); jgen.writeStringField("hydra:property", collectionAffordance.getRel()); // a) in the case of </Alice> :knows /bob the subject must be /Alice // b) in the case of <> orderedItem /latte-1 the subject is an anonymous resource of type // Order // c) in the case of </order/1> :seller </store> the object must be the store // 1. where is the information *about* the subject or object: the type or @id // 2. how to decide if the collection manages items for a subject or object? // ad 1.) // ad a) self rel of the Resource that has the collection affordance: looking through link // list // at serialization time is possible // ad b) a candidate is the class given as value of @ExposesResourceFor on the controller // that defines the method which leads us to believe we have a collection: // either a GET /orders handler having a collection return type or the POST /orders. // Works only if the GET or POST has no request mapping path of its own // an alternative is to use {} without type if @ExposesResourceFor is not present // ad c) like a // ad 2.) // we know the affordance is a collection // * we could pass information into build(rel), like // .rel().reverseRel("schema:seller").build() // * we could use build("myReversedTerm") and look at the @context to see if it is // reversed, // if so, we know that the manages block must use object not subject. However weird if // the // reverse term is never really used in the json-ld // * we could have a registry which says if a property is meant to be reversed in a // certain context // and use that to find out if we need subject or object, like :seller -> if (selfRel != null) { // prefer rev over rel, assuming that rev exists to be used by RDF serialization if (collectionAffordance.getRev() != null) { jgen.writeStringField("hydra:object", selfRel.getHref()); } else if (collectionAffordance.getRel() != null) { jgen.writeStringField("hydra:subject", selfRel.getHref()); } } else { // prefer rev over rel, assuming that rev exists to be used by RDF serialization if (collectionAffordance.getRev() != null) { jgen.writeObjectFieldStart("hydra:object"); jgen.writeEndObject(); } else if (collectionAffordance.getRel() != null) { jgen.writeObjectFieldStart("hydra:subject"); jgen.writeEndObject(); } } jgen.writeEndObject(); // end manages List<ActionDescriptor> actionDescriptors = collectionAffordance.getActionDescriptors(); if (!actionDescriptors.isEmpty()) { jgen.writeArrayFieldStart("hydra:operation"); } writeActionDescriptors(jgen, currentVocab, actionDescriptors); if (!actionDescriptors.isEmpty()) { jgen.writeEndArray(); // end hydra:operation } jgen.writeEndObject(); // end collection } jgen.writeEndArray(); } for (Affordance affordance : affordances) { final String rel = affordance.getRel(); List<ActionDescriptor> actionDescriptors = affordance.getActionDescriptors(); if (!actionDescriptors.isEmpty()) { if (!Link.REL_SELF.equals(rel)) { jgen.writeObjectFieldStart(rel); // begin rel } jgen.writeStringField(JsonLdKeywords.AT_ID, affordance.getHref()); jgen.writeArrayFieldStart("hydra:operation"); } writeActionDescriptors(jgen, currentVocab, actionDescriptors); if (!actionDescriptors.isEmpty()) { jgen.writeEndArray(); // end hydra:operation if (!Link.REL_SELF.equals(rel)) { jgen.writeEndObject(); // end rel } } } for (Link simpleLink : simpleLinks) { final String rel = simpleLink.getRel(); if (Link.REL_SELF.equals(rel)) { jgen.writeStringField("@id", simpleLink.getHref()); } else { String linkAttributeName = IanaRels.isIanaRel(rel) ? IANA_REL_PREFIX + rel : rel; jgen.writeObjectFieldStart(linkAttributeName); jgen.writeStringField("@id", simpleLink.getHref()); jgen.writeEndObject(); } } } catch (IntrospectionException e) { throw new RuntimeException(e); } }