edu.harvard.hms.dbmi.bd2k.irct.ws.rs.resultconverter.JSONTabularDataConverter.java Source code

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Here is the source code for edu.harvard.hms.dbmi.bd2k.irct.ws.rs.resultconverter.JSONTabularDataConverter.java

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/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package edu.harvard.hms.dbmi.bd2k.irct.ws.rs.resultconverter;

import java.io.IOException;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;

import javax.json.Json;
import javax.json.stream.JsonGenerator;
import javax.json.stream.JsonGeneratorFactory;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.StreamingOutput;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import edu.harvard.hms.dbmi.bd2k.irct.dataconverter.ResultDataConverter;
import edu.harvard.hms.dbmi.bd2k.irct.model.result.Result;
import edu.harvard.hms.dbmi.bd2k.irct.model.result.ResultDataType;
import edu.harvard.hms.dbmi.bd2k.irct.model.result.exception.PersistableException;
import edu.harvard.hms.dbmi.bd2k.irct.model.result.exception.ResultSetException;
import edu.harvard.hms.dbmi.bd2k.irct.model.result.tabular.Column;
import edu.harvard.hms.dbmi.bd2k.irct.model.result.tabular.ResultSet;

/**
 * A data converter that returns a JSON stream
 * 
 * @author Jeremy R. Easton-Marks
 *
 */
public class JSONTabularDataConverter implements ResultDataConverter {

    private Log log;

    public JSONTabularDataConverter() {
        log = LogFactory.getLog("JSON Tabular Data Converter");
    }

    @Override
    public ResultDataType getResultDataType() {
        return ResultDataType.TABULAR;
    }

    @Override
    public String getFileExtension() {
        return ".json";
    }

    @Override
    public String getName() {
        return "JSON";
    }

    @Override
    public String getMediaType() {
        return MediaType.APPLICATION_JSON;
    }

    @Override
    public StreamingOutput createStream(final Result result) {
        StreamingOutput stream = new StreamingOutput() {
            @Override
            public void write(OutputStream outputStream) throws IOException, WebApplicationException {
                JsonGenerator jg = null;
                ResultSet rs = null;
                try {
                    rs = (ResultSet) result.getData();
                    rs.load(result.getResultSetLocation());
                    Map<String, Object> properties = new HashMap<String, Object>(1);
                    JsonGeneratorFactory jgf = Json.createGeneratorFactory(properties);
                    jg = jgf.createGenerator(outputStream);

                    jg.writeStartObject(); //Start Object
                    jg.writeStartArray("columns");

                    // Get columns
                    for (Column column : rs.getColumns()) {
                        jg.write(column.toJson());
                    }
                    jg.writeEnd(); //End columns
                    jg.writeStartArray("data");

                    rs.beforeFirst();
                    while (rs.next()) {
                        jg.writeStartArray(); //Begin Row Array
                        for (int columnIndex = 0; columnIndex < rs.getColumnSize(); columnIndex++) {
                            String value = rs.getString(columnIndex);
                            if (value != null) {
                                jg.writeStartObject();
                                jg.write(rs.getColumn(columnIndex).getName(), rs.getString(columnIndex));
                                jg.writeEnd();
                            }

                        }
                        jg.writeEnd(); //End Row Array
                    }

                    jg.writeEnd(); //End data
                    jg.writeEnd(); //End Full Object

                } catch (ResultSetException | PersistableException e) {
                    log.info("Error creating JSON Stream: " + e.getMessage());
                } finally {

                    if (jg != null) {
                        jg.close();
                    }
                    if (rs != null && !rs.isClosed()) {
                        try {
                            rs.close();
                        } catch (ResultSetException e) {
                            e.printStackTrace();
                        }
                    }

                    if (outputStream != null) {
                        outputStream.close();
                    }
                }

            }
        };
        return stream;
    }
}