com.novartis.opensource.yada.format.ResultSetResultJSONConverter.java Source code

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Here is the source code for com.novartis.opensource.yada.format.ResultSetResultJSONConverter.java

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/**
 * Copyright 2016 Novartis Institutes for BioMedical Research Inc.
 * Licensed 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.novartis.opensource.yada.format;

import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import javax.sql.rowset.RowSetMetaDataImpl;

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

import com.novartis.opensource.yada.YADAQueryResult;
import com.novartis.opensource.yada.adaptor.JDBCAdaptor;

/**
 * @since 4.0.0
 * @author David Varon
 *
 */
public class ResultSetResultJSONConverter extends AbstractConverter {

    /**
     * Default constructor
     */
    public ResultSetResultJSONConverter() {
        // default constructor
    }

    /**
     * Constructor with {@link YADAQueryResult}
     * @param yqr the container for result processing artifacts
     */
    public ResultSetResultJSONConverter(YADAQueryResult yqr) {
        this.setYADAQueryResult(yqr);
    }

    /**
     * Unpacks data in a {@code ResultSet} and stuffs it in a JSON object. 
     * @see com.novartis.opensource.yada.format.AbstractConverter#convert(java.lang.Object)
     */
    @Override
    public Object convert(Object result) throws YADAConverterException {
        JSONArray rows = null;

        try {
            rows = getJSONRows((ResultSet) result);
        } catch (SQLException e) {
            String msg = "Unable to iterate over ResultSet";
            throw new YADAConverterException(msg, e);
        } catch (JSONException e) {
            String msg = "Unable to create JSONArray from ResultSet";
            throw new YADAConverterException(msg, e);
        }
        return rows;
    }

    /**
     * Converts data from a {@link java.sql.ResultSet} into a {@link JSONArray} containing
     * one {@link JSONObject} per row
     * @param rs the result set containing the data to convert to JSON
     * @return a json array containing the data
     * @throws SQLException when iteration or access to {@code rs} fails
     */
    protected JSONArray getJSONRows(ResultSet rs) throws SQLException {
        JSONArray rows = new JSONArray();
        ResultSetMetaData rsmd = rs.getMetaData();
        if (rsmd == null)
            rsmd = new RowSetMetaDataImpl();
        List<String> convertedResult = new ArrayList<>();
        while (rs.next()) {
            JSONObject row = new JSONObject();
            String colValue;
            for (int i = 1; i <= rsmd.getColumnCount(); i++) {
                String origColName = rsmd.getColumnName(i);
                if (!origColName.toLowerCase().equals(JDBCAdaptor.ROWNUM_ALIAS)) {
                    boolean harmonize = isHarmonized();
                    boolean prune = harmonize
                            ? ((JSONObject) this.harmonyMap).has(Harmonizer.PRUNE)
                                    && ((JSONObject) this.harmonyMap).getBoolean(Harmonizer.PRUNE)
                            : false;
                    String col = origColName;
                    if (harmonize) {
                        if (((JSONObject) this.harmonyMap).has(origColName)) {
                            col = ((JSONObject) this.harmonyMap).getString(origColName);
                        } else if (prune) {
                            col = "";
                        }
                    }

                    //TODO handle empty result set more intelligently
                    // OLD WAY adds headers to empty object when rs is empty
                    if (!"".equals(col)) {
                        if (null == rs.getString(origColName) || NULL.equals(rs.getString(origColName))) {
                            colValue = NULL_REPLACEMENT;
                        } else {
                            colValue = rs.getString(origColName);
                        }
                        row.put(col, colValue);
                    }
                }

            }
            rows.put(row);
            convertedResult.add(row.toString());
        }
        if (rows.length() > 0) {
            for (String key : JSONObject.getNames(rows.getJSONObject(0))) {
                getYADAQueryResult().addConvertedHeader(key);
            }
            getYADAQueryResult().getConvertedResults().add(convertedResult);
        }
        return rows;
    }
}