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Add JSON LD parser and serializer support for Apache Clerezza #146

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36 changes: 29 additions & 7 deletions integration/clerezza/README.md
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Expand Up @@ -3,24 +3,46 @@ Note: this is the documentation for the current unstable development branch. [Fo
JSONLD-Java Clerezza Integration module
=======================================

This module provide a `ParsingProvider`and `SerializingProvider` for Apache Clerezza. Those Providers plug into the Clerezza `Parser` and `Serializer` service infrastructure. Meaning that adding this bundle will allow Clerezza to parse and serialize JSON-LD.

USAGE
=====

From Maven
----------
Maven Dependency
----------------

<dependency>
<groupId>com.github.jsonld-java</groupId>
<artifactId>jsonld-java-clerezza</artifactId>
<version>0.4-SNAPSHOT</version>
<version>0.6.1-SNAPSHOT</version>
</dependency>

(Adjust for most recent <version>, as found in ``pom.xml``).

From OSGI
---------

Assuming the above Bundle is active in the OSGI Environment one can simple inject the `Serializer` and/or `Parser` service.

@Reference
private Serializer serializer;

@Reference
private Parser parser;


Normal Java
-----------

Both the `Parser` and `Serializer` also support `java.util.ServiceLoader`. So when running outside an OSGI environment one can use the `getInstance()` to obtain an instance.

Serializer serializer = Serializer.getInstance();

Parser parser = Parser.getInstance();

ClerezzaTripleCallback
------------------
Supported Formats
-----------------

The ClerezzaTripleCallback returns an instance of `org.apache.clerezza.rdf.core.MGraph`
The JSON-LD parser implementation supports `application/ld+json`. The serializer supports both `application/ld+json` and `application/json`.

See [ClerezzaTripleCallbackTest.java](./src/test/java/com/github/jsonldjava/clerezza/ClerezzaTripleCallbackTest.java) for example Usage.
The rational behind this is that the parser can not parse any JSON however the Serializer does generate valid JSON.
34 changes: 27 additions & 7 deletions integration/clerezza/pom.xml
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Expand Up @@ -22,6 +22,9 @@
<developer>
<name>Peter Ansell</name>
</developer>
<developer>
<name>Rupert Westenthaler</name>
</developer>
</developers>

<dependencies>
Expand All @@ -32,17 +35,30 @@
<type>jar</type>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>${project.groupId}</groupId>
<artifactId>jsonld-java</artifactId>
<version>${project.version}</version>
<type>test-jar</type>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.apache.clerezza</groupId>
<artifactId>rdf.core</artifactId>
</dependency>
<!-- OSGI related -->
<dependency>
<groupId>org.apache.felix</groupId>
<artifactId>org.apache.felix.scr.annotations</artifactId>
</dependency>


<!-- Test dependencies -->
<dependency>
<groupId>${project.groupId}</groupId>
<artifactId>jsonld-java</artifactId>
<version>${project.version}</version>
<type>test-jar</type>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.apache.clerezza</groupId>
<artifactId>rdf.ontologies</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
Expand All @@ -69,6 +85,10 @@
<groupId>org.jacoco</groupId>
<artifactId>jacoco-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.apache.felix</groupId>
<artifactId>maven-scr-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
Expand Down
112 changes: 112 additions & 0 deletions integration/clerezza/src/main/java/com/github/jsonldjava/clerezza/ClerezzaRDFParser.java
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@@ -0,0 +1,112 @@
package com.github.jsonldjava.clerezza;

import java.util.HashMap;
import java.util.Map;

import org.apache.clerezza.rdf.core.BNode;
import org.apache.clerezza.rdf.core.Language;
import org.apache.clerezza.rdf.core.Literal;
import org.apache.clerezza.rdf.core.NonLiteral;
import org.apache.clerezza.rdf.core.PlainLiteral;
import org.apache.clerezza.rdf.core.Resource;
import org.apache.clerezza.rdf.core.Triple;
import org.apache.clerezza.rdf.core.TripleCollection;
import org.apache.clerezza.rdf.core.TypedLiteral;
import org.apache.clerezza.rdf.core.UriRef;

import com.github.jsonldjava.core.JsonLdError;
import com.github.jsonldjava.core.JsonLdProcessor;
import com.github.jsonldjava.core.RDFDataset;
import com.github.jsonldjava.core.RDFParser;

/**
* Converts a Clerezza {@link TripleCollection} to the {@link RDFDataset} used
* by the {@link JsonLdProcessor}
*
* @author Rupert Westenthaler
*
*/
public class ClerezzaRDFParser implements RDFParser {

private static String RDF_LANG_STRING = "http://www.w3.org/1999/02/22-rdf-syntax-ns#langString";

private long count = 0;

@Override
public RDFDataset parse(Object input) throws JsonLdError {
count = 0;
final Map<BNode, String> bNodeMap = new HashMap<BNode, String>(1024);
final RDFDataset result = new RDFDataset();
if (input instanceof TripleCollection) {
for (final Triple t : ((TripleCollection) input)) {
handleStatement(result, t, bNodeMap);
}
}
bNodeMap.clear(); // help gc
return result;
}

private void handleStatement(RDFDataset result, Triple t, Map<BNode, String> bNodeMap) {
final String subject = getResourceValue(t.getSubject(), bNodeMap);
final String predicate = getResourceValue(t.getPredicate(), bNodeMap);
final Resource object = t.getObject();

if (object instanceof Literal) {

final String value = ((Literal) object).getLexicalForm();
final String language;
final String datatype;
if (object instanceof TypedLiteral) {
language = null;
datatype = getResourceValue(((TypedLiteral) object).getDataType(), bNodeMap);
} else if (object instanceof PlainLiteral) {
// we use RDF 1.1 literals so we do set the RDF_LANG_STRING
// datatype
datatype = RDF_LANG_STRING;
final Language l = ((PlainLiteral) object).getLanguage();
if (l == null) {
language = null;
} else {
language = l.toString();
}
} else {
throw new IllegalStateException("Unknown Literal class "
+ object.getClass().getName());
}
result.addTriple(subject, predicate, value, datatype, language);
count++;
} else {
result.addTriple(subject, predicate, getResourceValue((NonLiteral) object, bNodeMap));
count++;
}

}

/**
* The count of processed triples (not thread save)
*
* @return the count of triples processed by the last {@link #parse(Object)}
* call
*/
public long getCount() {
return count;
}

private String getResourceValue(NonLiteral nl, Map<BNode, String> bNodeMap) {
if (nl == null) {
return null;
} else if (nl instanceof UriRef) {
return ((UriRef) nl).getUnicodeString();
} else if (nl instanceof BNode) {
String bNodeId = bNodeMap.get(nl);
if (bNodeId == null) {
bNodeId = Integer.toString(bNodeMap.size());
bNodeMap.put((BNode) nl, bNodeId);
}
return new StringBuilder("_:b").append(bNodeId).toString();
} else {
throw new IllegalStateException("Unknwon NonLiteral type " + nl.getClass().getName()
+ "!");
}
}
}
8 changes: 5 additions & 3 deletions ...gration/clerezza/src/main/java/com/github/jsonldjava/clerezza/ClerezzaTripleCallback.java
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Expand Up @@ -20,6 +20,8 @@

public class ClerezzaTripleCallback implements JsonLdTripleCallback {

private static String RDF_LANG_STRING = "http://www.w3.org/1999/02/22-rdf-syntax-ns#langString";

private MGraph mGraph = new SimpleMGraph();
private Map<String, BNode> bNodeMap = new HashMap<String, BNode>();

Expand Down Expand Up @@ -52,10 +54,10 @@ private void triple(String s, String p, String value, String datatype, String la
if (language != null) {
object = new PlainLiteralImpl(value, new Language(language));
} else {
if (datatype != null) {
object = new TypedLiteralImpl(value, new UriRef(datatype));
} else {
if(datatype == null || RDF_LANG_STRING.equals(datatype)){
object = new PlainLiteralImpl(value);
} else {
object = new TypedLiteralImpl(value, new UriRef(datatype));
}
}

Expand Down
80 changes: 80 additions & 0 deletions integration/clerezza/src/main/java/com/github/jsonldjava/clerezza/JsonLdParsingProvider.java
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@@ -0,0 +1,80 @@
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to you under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.github.jsonldjava.clerezza;

import java.io.IOException;
import java.io.InputStream;

import org.apache.clerezza.rdf.core.MGraph;
import org.apache.clerezza.rdf.core.UriRef;
import org.apache.clerezza.rdf.core.serializedform.ParsingProvider;
import org.apache.clerezza.rdf.core.serializedform.SupportedFormat;
import org.apache.felix.scr.annotations.Component;
import org.apache.felix.scr.annotations.ConfigurationPolicy;
import org.apache.felix.scr.annotations.Service;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.github.jsonldjava.core.JsonLdError;
import com.github.jsonldjava.core.JsonLdProcessor;
import com.github.jsonldjava.utils.JsonUtils;

/**
* A {@link org.apache.clerezza.rdf.core.serializedform.ParsingProvider} for
* JSON-LD (application/ld+json) based on the java-jsonld library
*
* @author Rupert Westenthaler
*
*/
@Component(immediate = true, policy = ConfigurationPolicy.OPTIONAL)
@Service
@SupportedFormat("application/ld+json")
public class JsonLdParsingProvider implements ParsingProvider {

private final Logger logger = LoggerFactory.getLogger(getClass());

@Override
public void parse(MGraph target, InputStream serializedGraph, String formatIdentifier,
UriRef baseUri) {
// The callback will add parsed triples to the target MGraph
final ClerezzaTripleCallback ctc = new ClerezzaTripleCallback();
ctc.setMGraph(target);
Object input;
int startSize = 0;
if (logger.isDebugEnabled()) {
startSize = target.size();
}
final long start = System.currentTimeMillis();
try {
input = JsonUtils.fromInputStream(serializedGraph, "UTF-8");
} catch (final IOException e) {
logger.error("Unable to read from the parsed input stream", e);
throw new RuntimeException(e.getMessage(), e);
}
try {
JsonLdProcessor.toRDF(input, ctc);
} catch (final JsonLdError e) {
logger.error("Unable to parse JSON-LD from the parsed input stream", e);
throw new RuntimeException(e.getMessage(), e);
}
if (logger.isDebugEnabled()) {
logger.debug(" - parsed {} triples in {}ms", target.size() - startSize,
System.currentTimeMillis() - start);
}
}

}
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