org.apache.jena.riot.writer

Class JsonLDWriter

java.lang.Object

org.apache.jena.riot.writer.WriterDatasetRIOTBase

org.apache.jena.riot.writer.JsonLDWriter

All Implemented Interfaces:

WriterDatasetRIOT

public class JsonLDWriter
extends WriterDatasetRIOTBase

Writer that prints out JSON-LD. By default, the output is "compact" (in JSON-LD terminology), and the JSON is "pretty" (using line breaks). One can choose another form using one of the dedicated RDFFormats (JSONLD_EXPAND_PRETTY, etc.). For formats using a context (that is, which have an "@context" node), (compact and expand), this automatically generates a default one. One can pass a jsonld context using the (jena) Context mechanism, defining a (jena) Context (sorry for this clash of "contexts"), (cf. last argument in WriterDatasetRIOT.write(OutputStream out, DatasetGraph datasetGraph, PrefixMap prefixMap, String baseURI, Context context)) with:

 Context jenaContext = new Context()
 jenaCtx.set(JsonLDWriter.JSONLD_CONTEXT, contextAsJsonString);
 

where contextAsJsonString is a JSON string containing the value of the "@context". It is possible to change the content of the "@context" node in the output using the JSONLD_CONTEXT_SUBSTITUTION Symbol. For a frame output, one must pass a frame in the jenaContext using the JSONLD_FRAME Symbol. It is also possible to define the different options supported by JSONLD-java using the JSONLD_OPTIONS Symbol The JsonLDWriteContext is a convenience class that extends Context and provides methods to set the values of these different Symbols that are used in controlling the writing of JSON-LD. Note that this class also provides a static method to convert jena RDF data to the corresponding object in JsonLD API: toJsonLDJavaAPI(org.apache.jena.riot.RDFFormat.JSONLDVariant, DatasetGraph, PrefixMap, String, Context)

Field Summary

Fields

Modifier and Type	Field and Description
static Symbol	JSONLD_ADD_ALL_PREFIXES_TO_CONTEXT if creating a (jsonld) context from dataset, should we include all the prefixes defined in graph's prefix mappings value: a Boolean (default: true)
static Symbol	JSONLD_CONTEXT Expected value: the value of the "@context" (a JSON String, or the object expected by the JSONLD-java API)
static Symbol	JSONLD_CONTEXT_SUBSTITUTION Expected value: the value of the "@context" to be put in final output (a JSON String) This is NOT the context used to produce the output (given by JSONLD_CONTEXT, or computed from the input RDF.
static Symbol	JSONLD_FRAME value: a JSON String, or the frame object expected by JsonLdProcessor.frame
static Symbol	JSONLD_OPTIONS value: the option object expected by JsonLdProcessor (instance of JsonLdOptions)

Constructor Summary

Constructors

Constructor and Description
JsonLDWriter(RDFFormat syntaxForm)

Method Summary

Modifier and Type	Method and Description
Lang	getLang()
static Object	toJsonLDJavaAPI(RDFFormat.JSONLDVariant variant, DatasetGraph dataset, PrefixMap prefixMap, String baseURI, Context jenaContext) the JsonLD-java API object corresponding to a dataset and a JsonLD format.
void	write(OutputStream out, DatasetGraph dataset, PrefixMap prefixMap, String baseURI, Context context)
void	write(Writer out, DatasetGraph dataset, PrefixMap prefixMap, String baseURI, Context context) Use of Writer is discouraged - let the serializer manage character sets in accordance with the format

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

JSONLD_CONTEXT

public static final Symbol JSONLD_CONTEXT

Expected value: the value of the "@context" (a JSON String, or the object expected by the JSONLD-java API)

JSONLD_CONTEXT_SUBSTITUTION

public static final Symbol JSONLD_CONTEXT_SUBSTITUTION

Expected value: the value of the "@context" to be put in final output (a JSON String) This is NOT the context used to produce the output (given by JSONLD_CONTEXT, or computed from the input RDF. It is something that will replace the @context content. This is useful

1. for the cases you want to have a URI as value of @context, without having JSON-LD java to download it and
2. as a trick to change the URIs in your result.

Only for compact and flatten formats. Note that it is supposed to be a JSON String: to set the value of @context to a URI, the String must be quoted.

JSONLD_FRAME

public static final Symbol JSONLD_FRAME

value: a JSON String, or the frame object expected by JsonLdProcessor.frame

JSONLD_OPTIONS

public static final Symbol JSONLD_OPTIONS

value: the option object expected by JsonLdProcessor (instance of JsonLdOptions)

JSONLD_ADD_ALL_PREFIXES_TO_CONTEXT

public static final Symbol JSONLD_ADD_ALL_PREFIXES_TO_CONTEXT

if creating a (jsonld) context from dataset, should we include all the prefixes defined in graph's prefix mappings value: a Boolean (default: true)

Constructor Detail

JsonLDWriter

public JsonLDWriter(RDFFormat syntaxForm)

Method Detail

getLang

public Lang getLang()

write

public void write(Writer out,
                  DatasetGraph dataset,
                  PrefixMap prefixMap,
                  String baseURI,
                  Context context)

Description copied from interface: WriterDatasetRIOT

Use of Writer is discouraged - let the serializer manage character sets in accordance with the format

Specified by:

write in interface WriterDatasetRIOT

Specified by:

write in class WriterDatasetRIOTBase

Parameters:

out - Writer

dataset - DatasetGraph to be written

prefixMap - PrefixMap - maybe null (default should be to use the prefixmapping from the Graph)

baseURI - base URI - may be null for "none"

context - Context (see specific implementation for details)

write

public void write(OutputStream out,
                  DatasetGraph dataset,
                  PrefixMap prefixMap,
                  String baseURI,
                  Context context)

Specified by:

write in interface WriterDatasetRIOT

Specified by:

write in class WriterDatasetRIOTBase

Parameters:

out - OutputStream

dataset - DatasetGraph to be written

prefixMap - PrefixMap - maybe null (default should be to use the prefixmapping from the Graph)

baseURI - base URI - may be null for "none"

context - Context (see specific implementation for details)

toJsonLDJavaAPI

public static Object toJsonLDJavaAPI(RDFFormat.JSONLDVariant variant,
                                     DatasetGraph dataset,
                                     PrefixMap prefixMap,
                                     String baseURI,
                                     Context jenaContext)
                              throws com.github.jsonldjava.core.JsonLdError,
                                     com.fasterxml.jackson.core.JsonParseException,
                                     IOException

the JsonLD-java API object corresponding to a dataset and a JsonLD format.

Throws:

com.github.jsonldjava.core.JsonLdError

com.fasterxml.jackson.core.JsonParseException

IOException