org.kawanfw.sql.json.JsonColPosition.java Source code

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Here is the source code for org.kawanfw.sql.json.JsonColPosition.java

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/*
 * This file is part of AceQL. 
 * AceQL: Remote JDBC access over HTTP.                                     
 * Copyright (C) 2015,  KawanSoft SAS
 * (http://www.kawansoft.com). All rights reserved.                                
 *                                                                               
 * AceQL is free software; you can redistribute it and/or                 
 * modify it under the terms of the GNU Lesser General Public                    
 * License as published by the Free Software Foundation; either                  
 * version 2.1 of the License, or (at your option) any later version.            
 *                                                                               
 * AceQL is distributed in the hope that it will be useful,               
 * but WITHOUT ANY WARRANTY; without even the implied warranty of                
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU             
 * Lesser General Public License for more details.                               
 *                                                                               
 * You should have received a copy of the GNU Lesser General Public              
 * License along with this library; if not, write to the Free Software           
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  
 * 02110-1301  USA
 *
 * Any modifications to this file must keep this entire header
 * intact.
 */
package org.kawanfw.sql.json;

import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;

import org.json.simple.JSONObject;
import org.json.simple.JSONValue;
import org.kawanfw.commons.util.FrameworkDebug;
import org.kawanfw.commons.util.HtmlConverter;

/**
 * 
 * Class to transport Result Set column names and
 *         values between host <==> PC.
 *         
 * @author Nicolas de Pomereu   
 */

public class JsonColPosition {

    /** For debug info */
    private static boolean DEBUG = FrameworkDebug.isSet(JsonColPosition.class);

    /**
     * Format for JSON String the Map<String, Integer> of (column name, column
     * position) of a result set
     * 
     * @param columnPositions
     *            the Map<String, Integer> of (column name, column position) of
     *            a result set
     * @return the formated JSON string ready for transport
     */

    public static String toJson(Map<String, Integer> columnPositions) {
        if (columnPositions == null) {
            throw new IllegalArgumentException("columsAndValues is null!");
        }

        String jsonString = JSONValue.toJSONString(columnPositions);

        jsonString = HtmlConverter.toHtml(jsonString);

        debug(" toJson(Map<String, Integer> columnPositions) jsonString: " + jsonString);
        return jsonString;
    }

    /**
     * Format from JSON string Map<String, Integer> of (column name, column
     * position) of a result set
     * 
     * @param jsonString
     *            formated JSON string containing the Map<String, Integer> of
     *            (column name, column position)
     * @return Map<String, Integer> of (column name, column position)
     */
    public static Map<String, Integer> fromJson(String jsonString) {
        if (jsonString == null) {
            throw new IllegalArgumentException("jsonString is null!");
        }

        jsonString = HtmlConverter.fromHtml(jsonString);

        // Revert it
        Object obj = JSONValue.parse(jsonString);
        JSONObject mapBack = (JSONObject) obj;

        debug("jsonString        : " + jsonString);
        debug("mapBack.toString(): " + mapBack.toString());

        Map<String, Integer> columnPositions = new LinkedHashMap<String, Integer>();

        Set<?> set = mapBack.keySet();

        for (Iterator<?> iterator = set.iterator(); iterator.hasNext();) {

            String key = (String) iterator.next();
            long value = (Long) mapBack.get(key);

            columnPositions.put(key, (int) value);
        }

        // free objects
        obj = null;
        mapBack = null;

        return columnPositions;
    }

    /**
     * @param args
     */
    public static void main(String[] args) throws Exception {
        Map<String, Integer> columnPositions = new LinkedHashMap<String, Integer>();
        columnPositions.put("col_1", 1);
        columnPositions.put("col_2", 2);
        columnPositions.put("col_3", 2);
        System.out.println(columnPositions);

        String jsonString = toJson(columnPositions);
        System.out.println(jsonString);
        System.out.println();

        Map<String, Integer> columnPositionsBack = fromJson(jsonString);
        System.out.println(columnPositionsBack);

    }

    private static void debug(String s) {
        if (DEBUG) {
            System.out.println(s);
        }
    }

}