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package com.eduworks.cruncher.rdf;

import com.eduworks.lang.util.EwJson;
import com.eduworks.levr.rdf.RdfXmlParser;
import com.eduworks.resolver.Context;
import com.eduworks.resolver.Cruncher;
import com.github.jsonldjava.core.JsonLdConsts;
import com.github.jsonldjava.core.JsonLdError;
import com.github.jsonldjava.core.JsonLdOptions;
import com.github.jsonldjava.core.JsonLdProcessor;
import com.github.jsonldjava.utils.JsonUtils;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

/**
 *
 * @author fray
 */
public class CruncherRdfToJsonLd extends Cruncher
{
    
    @Override
    public Object resolve(Context c, Map parameters, Map dataStreams) throws JSONException
    {
        try
        {
            String obj = getObjAsString(c, parameters, dataStreams);
            if (obj == null) return null;
            
            JsonLdProcessor.registerRDFParser("RDF/XML", new RdfXmlParser(true));
            
            JsonLdOptions options = new JsonLdOptions();
            options.outputForm=JsonLdConsts.COMPACTED;
            options.format="RDF/XML";
            Object output =  JsonLdProcessor.fromRDF(obj, options);	
            
            return new JSONObject(JsonUtils.toString(output));
        }
        catch (IOException ex)
        {
            Logger.getLogger(CruncherJsonLdExpand.class.getName()).log(Level.SEVERE, null, ex);
        }
        catch (JsonLdError ex)
        {
            Logger.getLogger(CruncherJsonLdExpand.class.getName()).log(Level.SEVERE, null, ex);
        }
        return null;
    }
    
    @Override
    public String getDescription()
    {
        return "Performs a JSON-LD Expand algorithm on the obj.";
    }
    
    @Override
    public String getReturn()
    {
        return "JSON-LD";
    }
    
    @Override
    public String getAttribution()
    {
        return ATTRIB_NONE;
    }
    
    @Override
    public JSONObject getParameters() throws JSONException
    {
        return jo("obj", "JSONObject|JSONArray");
    }
    
}