DateTime.java

package org.drip.analytics.date;

/*
 * -*- mode: java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 */

/*!
 * Copyright (C) 2020 Lakshmi Krishnamurthy
 * Copyright (C) 2019 Lakshmi Krishnamurthy
 * Copyright (C) 2018 Lakshmi Krishnamurthy
 * Copyright (C) 2017 Lakshmi Krishnamurthy
 * Copyright (C) 2016 Lakshmi Krishnamurthy
 * Copyright (C) 2015 Lakshmi Krishnamurthy
 * Copyright (C) 2014 Lakshmi Krishnamurthy
 * Copyright (C) 2013 Lakshmi Krishnamurthy
 * Copyright (C) 2012 Lakshmi Krishnamurthy
 * Copyright (C) 2011 Lakshmi Krishnamurthy
 * 
 *  This file is part of DROP, an open-source library targeting analytics/risk, transaction cost analytics,
 *      asset liability management analytics, capital, exposure, and margin analytics, valuation adjustment
 *      analytics, and portfolio construction analytics within and across fixed income, credit, commodity,
 *      equity, FX, and structured products. It also includes auxiliary libraries for algorithm support,
 *      numerical analysis, numerical optimization, spline builder, model validation, statistical learning,
 *      and computational support.
 *  
 *      https://lakshmidrip.github.io/DROP/
 *  
 *  DROP is composed of three modules:
 *  
 *  - DROP Product Core - https://lakshmidrip.github.io/DROP-Product-Core/
 *  - DROP Portfolio Core - https://lakshmidrip.github.io/DROP-Portfolio-Core/
 *  - DROP Computational Core - https://lakshmidrip.github.io/DROP-Computational-Core/
 * 
 *  DROP Product Core implements libraries for the following:
 *  - Fixed Income Analytics
 *  - Loan Analytics
 *  - Transaction Cost Analytics
 * 
 *  DROP Portfolio Core implements libraries for the following:
 *  - Asset Allocation Analytics
 *  - Asset Liability Management Analytics
 *  - Capital Estimation Analytics
 *  - Exposure Analytics
 *  - Margin Analytics
 *  - XVA Analytics
 * 
 *  DROP Computational Core implements libraries for the following:
 *  - Algorithm Support
 *  - Computation Support
 *  - Function Analysis
 *  - Model Validation
 *  - Numerical Analysis
 *  - Numerical Optimizer
 *  - Spline Builder
 *  - Statistical Learning
 * 
 *  Documentation for DROP is Spread Over:
 * 
 *  - Main                     => https://lakshmidrip.github.io/DROP/
 *  - Wiki                     => https://github.com/lakshmiDRIP/DROP/wiki
 *  - GitHub                   => https://github.com/lakshmiDRIP/DROP
 *  - Repo Layout Taxonomy     => https://github.com/lakshmiDRIP/DROP/blob/master/Taxonomy.md
 *  - Javadoc                  => https://lakshmidrip.github.io/DROP/Javadoc/index.html
 *  - Technical Specifications => https://github.com/lakshmiDRIP/DROP/tree/master/Docs/Internal
 *  - Release Versions         => https://lakshmidrip.github.io/DROP/version.html
 *  - Community Credits        => https://lakshmidrip.github.io/DROP/credits.html
 *  - Issues Catalog           => https://github.com/lakshmiDRIP/DROP/issues
 *  - JUnit                    => https://lakshmidrip.github.io/DROP/junit/index.html
 *  - Jacoco                   => https://lakshmidrip.github.io/DROP/jacoco/index.html
 * 
 *  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.
 */

/**
 * <i>DateTime</i> provides the representation of the instantiation-time date and time objects. It provides
 * the following functionality:
 *
 *  <br><br>
 *  <ul>
 *      <li>
 *          Instantiation-time and Explicit Date/Time Construction
 *      </li>
 *      <li>
 *          Retrieval of Date/Time Fields
 *      </li>
 *      <li>
 *          Serialization/De-serialization to and from Byte Arrays
 *      </li>
 *  </ul>
 * 
 * <br><br>
 *
 * The References are:
 *  <ul>
 *      <li>
 *          Fliegel, H. F., and T. C. van Flandern (1968): A Machine Algorithm for Processing Calendar Dates
 *              <i>Communications of the ACM</i> <b>11</b> 657
 *      </li>
 *      <li>
 *          Fenton, D. (2001): Julian to Calendar Date Conversion
 *              http://mathforum.org/library/drmath/view/51907.html
 *      </li>
 *  </ul>
 *
 *  <br><br>
 *  <ul>
 *      <li><b>Module </b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/ProductCore.md">Product Core Module</a></li>
 *      <li><b>Library</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/FixedIncomeAnalyticsLibrary.md">Fixed Income Analytics</a></li>
 *      <li><b>Project</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/src/main/java/org/drip/analytics/README.md">Date, Cash Flow, and Cash Flow Period Measure Generation Utilities</a></li>
 *      <li><b>Package</b> = <a href = "https://github.com/lakshmiDRIP/DROP/tree/master/src/main/java/org/drip/analytics/date/README.md">Date and Time Creation, Manipulation, and Usage</a></li>
 *  </ul>
 * 
 * @author Lakshmi Krishnamurthy
 */

public class DateTime {
    private long _lTime = 0L;
    private double _dblDate = java.lang.Double.NaN;

    /**
     * Default constructor initializes the time and date to the current time and current date.
     * 
     * @throws java.lang.Exception Thrown if the DateTime Instance cannot be created
     */

    public DateTime()
        throws java.lang.Exception
    {
        _lTime = System.nanoTime();

        java.util.Date dtNow = new java.util.Date();

        _dblDate = org.drip.analytics.date.DateUtil.ToJulian (org.drip.analytics.date.DateUtil.Year (dtNow),
            org.drip.analytics.date.DateUtil.Month (dtNow), org.drip.analytics.date.DateUtil.Day (dtNow));
    }

    /**
     * Constructs DateTime from separate date and time inputs 
     * 
     * @param dblDate Date
     * @param lTime Time
     * 
     * @throws java.lang.Exception Thrown on Invalid Inputs
     */

    public DateTime (
        final double dblDate,
        final long lTime)
        throws java.lang.Exception
    {
        if (!org.drip.numerical.common.NumberUtil.IsValid (dblDate))
            throw new java.lang.Exception ("DateTime ctr: Invalid Inputs!");

        _lTime = lTime;
        _dblDate = dblDate;
    }

    /**
     * Retrieve the Date
     * 
     * @return date
     */

    public double date()
    {
        return _dblDate;
    }

    /**
     * Retrieve the time
     * 
     * @return time
     */

    public long time()
    {
        return _lTime;
    }
}