001/*
002 * Stallion Core: A Modern Web Framework
003 *
004 * Copyright (C) 2015 - 2016 Stallion Software LLC.
005 *
006 * This program is free software: you can redistribute it and/or modify it under the terms of the
007 * GNU General Public License as published by the Free Software Foundation, either version 2 of
008 * the License, or (at your option) any later version. This program is distributed in the hope that
009 * it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
010 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
011 * License for more details. You should have received a copy of the GNU General Public License
012 * along with this program.  If not, see <http://www.gnu.org/licenses/gpl-2.0.html>.
013 *
014 *
015 *
016 */
017
018package io.stallion.dataAccess;
019
020import io.stallion.settings.Settings;
021
022import java.util.concurrent.atomic.AtomicInteger;
023
024/**
025 * This generates unique IDs (unique within a particular stallion application) based on the current time.
026 * This is used in file based systems.
027 *
028 * Generates a unique ticket based on a counter, the current time rounded to nearest 10 seconds, and the node number.
029 * This will create duplicates if you need to generate more than 10,000 tickets in a second.
030 * This will also exceed the MAX_SAFE_INTEGER value for javascript around the year 2248.
031 *
032 *
033 */
034public class TimebasedTickets implements Tickets {
035    private AtomicInteger i = new AtomicInteger();
036    private Long baseSeconds = null;
037    private static int loadedCount = 0;
038
039    public TimebasedTickets() {
040        // If we reload tickets during a test, we need to start with a higher increment or else
041        // we will generate the same IDs over again. If we run more than 100 test cases with
042        // full app context reloads in a single
043        // second, then we might get duplicate IDs, but that is probably impossible
044        loadedCount++;
045        i.set(loadedCount * 1000);
046    }
047
048
049
050
051    /**
052     *
053     *
054     * @return
055     */
056    @Override
057    public Long nextId() {
058        Integer counter = i.incrementAndGet();
059        if (counter > 99500) {
060            i.set(0);
061        }
062        Long currentSeconds = System.currentTimeMillis() / 1000;
063        Long sec = currentSeconds - getBaseSeconds();
064        Long ticket = ((sec) * 1000000) + (counter * 10) + Settings.instance().getNodeNumber();
065        return ticket;
066    }
067
068    private Long getBaseSeconds() {
069        if (baseSeconds == null) {
070            baseSeconds = Settings.instance().getAppCreatedMillis() / 1000;
071        }
072        return baseSeconds;
073    }
074}