de.terrestris.shogun.deserializer.DateDeserializer.java Source code

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Here is the source code for de.terrestris.shogun.deserializer.DateDeserializer.java

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/* Copyright (c) 2012-2014, terrestris GmbH & Co. KG
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. Neither the name of the copyright holder nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * (This is the BSD 3-Clause, sometimes called 'BSD New' or 'BSD Simplified',
 * see http://opensource.org/licenses/BSD-3-Clause)
 */
package de.terrestris.shogun.deserializer;

import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

import org.apache.log4j.Logger;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;

/**
 * Class responsible for deserializing a date.
 *
 * Makes a Date object out of an UNIX timestamp or a formatted date string.
 *
 * @author terrestris GmbH & Co. KG
 *
 */
public class DateDeserializer extends JsonDeserializer<Date> {

    private static Logger LOGGER = Logger.getLogger(DateDeserializer.class);

    private static String DATE_FORMAT = "dd.MM.yyyy HH:mm:ss";

    private static String[] FORMATTED_DATE_HINT_CHARS = { ":", "." };

    /**
     * Does some simple checks to determine whether we we're passed a formatted
     * date string. This is far from being complete, but does the job for the
     * current purposes.
     *
     * @param jsonStr
     * @return Whether the passed string looked like a formatted date.
     */
    public static boolean looksLikeFormattedDateString(String jsonStr) {
        boolean looksLikeFormattedDate = false;
        int formattedLen = DATE_FORMAT.length();

        if (jsonStr != null) {
            if (jsonStr.length() == formattedLen) {
                for (int idx = 0; idx < FORMATTED_DATE_HINT_CHARS.length; idx++) {
                    if (!jsonStr.contains(FORMATTED_DATE_HINT_CHARS[idx])) {
                        looksLikeFormattedDate = false;
                        break;
                    } else {
                        looksLikeFormattedDate = true;
                    }
                }
            }
        }

        return looksLikeFormattedDate;
    }

    /**
     * This method tries to convert a passed date string into a date.
     *
     * Currently only strings formatted as <code>dd.MM.yyyy HH:mm:ss</code> are
     * supported.
     *
     * @param jsonStr
     * @return a <code>Date</code>-object or null.
     */
    public static Date parseCommonlyFormattedDate(String jsonStr) {
        SimpleDateFormat parserSDF = new SimpleDateFormat(DATE_FORMAT);
        parserSDF.setLenient(false);

        Date parsedDate = null;

        String failNotice = "Failed to parse string '" + jsonStr + "' with format '" + DATE_FORMAT + "'";
        try {
            parsedDate = parserSDF.parse(jsonStr);
        } catch (ParseException e) {
            LOGGER.error(failNotice + ": " + e.getMessage());
        }
        if (parsedDate == null) {
            LOGGER.info(failNotice);
        }
        return parsedDate;
    }

    /**
     * Overwrite the deserializer for date strings in the form of a
     * unix timestamp (1293836400).
     *
     * This method will also try to interpret strings like "30.04.2013 13:43:55"
     * as dates.
     */
    @Override
    public Date deserialize(JsonParser jsonParser, DeserializationContext context)
            throws IOException, JsonProcessingException {

        Date deserializedDate = null;
        String s = jsonParser.getText();

        if (DateDeserializer.looksLikeFormattedDateString(s)) {
            deserializedDate = DateDeserializer.parseCommonlyFormattedDate(s);
        } else {
            String failNotice = "Failed to interpret string '" + s
                    + "' as java.lang.Long. That string did not look like a " + "formatted date either.";
            try {
                Long number = new Long(s);
                deserializedDate = new Date(number);
            } catch (NumberFormatException e) {
                LOGGER.error(failNotice + " : " + e.getMessage());
            }
        }
        return deserializedDate;
    }

}