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ObServe Toolkit Common Dto module
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/*
 * Copyright (C) 2008 Google 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 fr.ird.observe.gson;

/*
 * #%L
 * ObServe Toolkit :: Common Dto
 * %%
 * Copyright (C) 2017 - 2020 IRD, Ultreia.io
 * %%
 * 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
 * .
 * #L%
 */


import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;
import com.google.gson.JsonPrimitive;
import com.google.gson.JsonSerializationContext;
import com.google.gson.JsonSerializer;
import com.google.gson.JsonSyntaxException;

import java.lang.reflect.Type;
import java.sql.Timestamp;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Objects;

/**
 * This type adapter supports three subclasses of date: Date, Timestamp, and
 * java.sql.Date.
 *
 * @author Inderjeet Singh
 * @author Joel Leitch
 * @author Kevin Morin : [email protected]
 */
public class DateAdapter implements JsonSerializer, JsonDeserializer {

    private final DateFormat iso8601Format;

    DateAdapter() {
        this.iso8601Format = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
    }

    // These methods need to be synchronized since JDK DateFormat classes are not thread-safe
    public JsonElement serialize(Date src, Type typeOfSrc, JsonSerializationContext context) {
        synchronized (iso8601Format) {
            String dateFormatAsString = iso8601Format.format(src);
            return new JsonPrimitive(dateFormatAsString);
        }
    }

    public Date deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
            throws JsonParseException {
        if (!(json instanceof JsonPrimitive)) {
            throw new JsonParseException("The date should be a string value");
        }
        Date date = deserializeToDate(json);
        Objects.requireNonNull(date);
        if (typeOfT == Date.class) {
            return date;
        } else if (typeOfT == Timestamp.class) {
            return new Timestamp(date.getTime());
        } else if (typeOfT == java.sql.Date.class) {
            return new java.sql.Date(date.getTime());
        } else {
            throw new IllegalArgumentException(getClass() + " cannot deserialize to " + typeOfT);
        }
    }

    private Date deserializeToDate(JsonElement json) {
        String stringDate = json.getAsString();
        if (stringDate.matches("^([\\+-]?\\d{4}(?!\\d{2}\\b))((-?)((0[1-9]|1[0-2])(\\3([12]\\d|0[1-9]|3[01]))?|W([0-4]\\d|5[0-2])(-?[1-7])?|(00[1-9]|0[1-9]\\d|[12]\\d{2}|3([0-5]\\d|6[1-6])))([T\\s]((([01]\\d|2[0-3])((:?)[0-5]\\d)?|24\\:?00)([\\.,]\\d+(?!:))?)?(\\17[0-5]\\d([\\.,]\\d+)?)?([zZ]|([\\+-])([01]\\d|2[0-3]):?([0-5]\\d)?)?)?)?$")) {
            synchronized (iso8601Format) {
                try {
                    return iso8601Format.parse(json.getAsString());
                } catch (ParseException e) {
                    throw new JsonSyntaxException(json.getAsString(), e);
                }
            }
        } else {
            return null;
        }

    }

}