JsonUtil.java example

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activityinfo-master
package org.activityinfo.legacy.shared.util;

/*
 * #%L
 * ActivityInfo Server
 * %%
 * Copyright (C) 2009 - 2013 UNICEF
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, either version 3 of the 
 * License, or (at your option) any later version.
 * 
 * This program 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 General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public 
 * License along with this program.  If not, see
 * <http://www.gnu.org/licenses/gpl-3.0.html>.
 * #L%
 */

import com.bedatadriven.rebar.time.calendar.LocalDate;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import org.activityinfo.legacy.shared.Log;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

public class JsonUtil {

    private JsonUtil() {
    }

    public static JsonObject parse(String json) {
        return (JsonObject) new JsonParser().parse(json);
    }

    public static JsonObject encodeMap(Map<String, Object> map) {
        JsonObject root = new JsonObject();
        for (Entry<String, Object> property : map.entrySet()) {
            if (property.getValue() != null) {
                JsonObject value = new JsonObject();

                if (property.getValue() instanceof String) {
                    value.addProperty("type", "String");
                    value.addProperty("value", (String) property.getValue());
                } else if (property.getValue() instanceof Integer) {
                    value.addProperty("type", "Integer");
                    value.addProperty("value", (Integer) property.getValue());
                } else if (property.getValue() instanceof Double) {
                    value.addProperty("type", "Double");
                    value.addProperty("value", (Double) property.getValue());
                } else if (property.getValue() instanceof Date) {
                    Date date = (Date) property.getValue();

                    value.addProperty("type", "Date");
                    value.addProperty("time", date.getTime());
                } else if (property.getValue() instanceof Boolean) {
                    value.addProperty("type", "Boolean");
                    value.addProperty("value", (Boolean) property.getValue());
                } else if (property.getValue() instanceof LocalDate) {
                    value.addProperty("type", "LocalDate");
                    value.addProperty("value", property.getValue().toString());

                } else {
                    Log.error("Cannot convert handle map value '" + property.getKey() + ", type " + property.getKey() +
                              ": " + property.getValue().getClass().getName());
                    value = null;
                }

                if (value != null) {
                    root.add(property.getKey(), value);
                }
            }
        }
        return root;
    }

    public static Map<String, Object> decodeMap(JsonObject root) {
        Map<String, Object> map = new HashMap<String, Object>();
        for (Entry<String, JsonElement> property : root.entrySet()) {
            JsonObject value = (JsonObject) property.getValue();
            String type = value.get("type").getAsString();

            if ("String".equals(type)) {
                map.put(property.getKey(), value.get("value").getAsString());
            } else if ("Integer".equals(type)) {
                map.put(property.getKey(), value.get("value").getAsInt());
            } else if ("Double".equals(type)) {
                map.put(property.getKey(), value.get("value").getAsDouble());
            } else if ("Date".equals(type)) {
                map.put(property.getKey(), new Date(value.get("time").getAsLong()));
            } else if ("Boolean".equals(type)) {
                map.put(property.getKey(), value.get("value").getAsBoolean());
            } else if ("LocalDate".equals(type)) {
                map.put(property.getKey(), LocalDate.parse(value.get("value").getAsString()));
            } else {
                throw new IllegalArgumentException("map contains key with unsupported value type -- " +
                                                   property.getKey() + ": " + type);
            }

        }
        return map;
    }
}