org.aksw.jena_sparql_api.stmt.SPARQLResultSinkPrint Maven / Gradle / Ivy

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package org.aksw.jena_sparql_api.stmt;

import java.io.PrintStream;

import org.apache.jena.query.ResultSet;
import org.apache.jena.query.ResultSetFormatter;
import org.apache.jena.sparql.core.Quad;

import com.google.gson.Gson;

/**
 * Print non-quad results by default to stderr
 *
 * @author raven
 *
 */
public class SPARQLResultSinkPrint
    implements SPARQLResultSink
{
    protected Gson gson;
    protected PrintStream out;

    public SPARQLResultSinkPrint() {
        this(null, null);
    }

    public SPARQLResultSinkPrint(PrintStream out) {
        this(out, null);
    }

    public SPARQLResultSinkPrint(PrintStream out, Gson gson) {
        super();
        this.out = out != null ? out : System.err;
        this.gson = gson != null ? gson : new Gson();
    }

    @Override
    public void onResultSet(ResultSet rs) {
        String str = ResultSetFormatter.asText(rs);
        out.println(str);
    }

    @Override
    public void onJson(com.google.gson.JsonElement value) {
        String json = gson.toJson(value);
        out.println(json);
    }


    @Override
    public void onQuad(Quad value) {
    }

    @Override
    public void close() throws Exception {

    }

    @Override
    public void flush() {
        out.flush();
    }

}