com.blackberry.logdriver.timestamp.Rfc3164TimestampParser.java Source code

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Here is the source code for com.blackberry.logdriver.timestamp.Rfc3164TimestampParser.java

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/** Copyright (c) 2014 BlackBerry Limited
 *
 *  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. 
 */

/**
 * Parses timestamps according to RFC3164.
 * <p>
 * This class uses SimpleDateFormat, and so it is not thread safe.
 */
package com.blackberry.logdriver.timestamp;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

import org.apache.commons.lang.time.FastDateFormat;

public class Rfc3164TimestampParser implements TimestampParser {
    private final SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy MMM dd HH:mm:ss");
    private final FastDateFormat dateFormatWriter = FastDateFormat.getInstance("MMM dd HH:mm:ss");

    @Override
    public String[] splitLine(String line) {
        if (line.length() >= 16) {
            String[] result = new String[2];
            result[0] = line.substring(0, 15);
            result[1] = line.substring(16);
            return result;
        } else {
            return new String[] { null, line };
        }
    }

    @Override
    public long parseTimestatmp(String timestamp) throws ParseException {
        if (timestamp == null) {
            throw new ParseException("Timestamp is null", 0);
        }

        // Before we parse the date, add the current year to the string. That way,
        // we get a correct timestamp. If I try to add the year after, we run into
        // issues with leap years.
        Calendar currentCalendar = Calendar.getInstance();
        int currentYear = currentCalendar.get(Calendar.YEAR);
        Date date = dateFormat.parse(currentYear + " " + timestamp);
        Calendar logCalendar = Calendar.getInstance();
        logCalendar.setTime(date);

        // If today is the first of January, and the log is for the 31st of
        // December, then we probably just used the wrong year. So lets roll the
        // year back by one in that case.
        if (logCalendar.get(Calendar.DAY_OF_MONTH) == 31 && logCalendar.get(Calendar.MONTH) == Calendar.DECEMBER
                && currentCalendar.get(Calendar.DAY_OF_MONTH) == 1
                && currentCalendar.get(Calendar.MONTH) == Calendar.JANUARY) {
            logCalendar.add(Calendar.YEAR, -1);

            // Contrariwise, a bad clock can give us Jan 1 logs on December 31
        } else if (currentCalendar.get(Calendar.DAY_OF_MONTH) == 31
                && currentCalendar.get(Calendar.MONTH) == Calendar.DECEMBER
                && logCalendar.get(Calendar.DAY_OF_MONTH) == 1
                && logCalendar.get(Calendar.MONTH) == Calendar.JANUARY) {
            logCalendar.add(Calendar.YEAR, 1);

        }

        return logCalendar.getTimeInMillis();
    }

    @Override
    public String timestampToString(long timestamp) {
        return dateFormatWriter.format(timestamp);
    }
}