DatetimeFormatParser.java

/*
** Module   : DatetimeFormatParser.java
** Abstract : Base class for Progress datetime/datetime-tz format parsers/formatters.
**
** Copyright (c) 2021, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------Description---------------------------------
** 001 VVT 20210426 Created initial version.
**     VVT 20210624 Javadoc fixed
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero 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 Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
**   Under Section 7 of the GNU Affero GPL version 3, the following additional
**   terms apply to the works covered under the License.  These additional terms
**   are non-permissive additional terms allowed under Section 7 of the GNU
**   Affero GPL version 3 and may not be removed by you.
**
**   0. Attribution Requirement.
**
**     You must preserve all legal notices or author attributions in the covered
**     work or Appropriate Legal Notices displayed by works containing the covered
**     work.  You may not remove from the covered work any author or developer
**     credit already included within the covered work.
**
**   1. No License To Use Trademarks.
**
**     This license does not grant any license or rights to use the trademarks
**     Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
**     of Golden Code Development Corporation. You are not authorized to use the
**     name Golden Code, FWD, or the names of any author or contributor, for
**     publicity purposes without written authorization.
**
**   2. No Misrepresentation of Affiliation.
**
**     You may not represent yourself as Golden Code Development Corporation or FWD.
**
**     You may not represent yourself for publicity purposes as associated with
**     Golden Code Development Corporation, FWD, or any author or contributor to
**     the covered work, without written authorization.
**
**   3. No Misrepresentation of Source or Origin.
**
**     You may not represent the covered work as solely your work.  All modified
**     versions of the covered work must be marked in a reasonable way to make it
**     clear that the modified work is not originating from Golden Code Development
**     Corporation or FWD.  All modified versions must contain the notices of
**     attribution required in this license.
*/
package com.goldencode.p2j.util;

/**
 * Base class for Progress datetime/datetime-tz format parsers/formatters.
 * 
 * The {@link #parse(String)} method is responsible for checking the
 * Progress datetime/datetime-tz format validity.
 * 
 * Also this class provides a set of callback methods,
 * each callback is called when the corresponding format component is parsed.
 * 
 * By default, all callbacks do nothing, they are expected to be re-defined in subclasses.
 */
public class DatetimeFormatParser
extends DateFormatParser
{
   /**
    * The hours component of the date spec was parsed.
    * 
    * @param startIdx
    *        the component start index, zero based
    * @param endIdx
    *        the component end index, zero based, exclusive. The end index is
    *        always greater than the start index.
    */
   protected void visitHours(final int startIdx, final int endIdx)
   {
      // no-op
   }

   /**
    * The minutes component of the date spec was parsed.
    * 
    * @param startIdx
    *        the component start index, zero based
    * @param endIdx
    *        the component end index, zero based, exclusive. The end index is
    *        always greater than the start index.
    */
   protected void visitMinutes(final int startIdx, final int endIdx)
   {
      // no-op
   }

   /**
    * The seconds component of the date spec was parsed.
    * 
    * @param startIdx
    *        the component start index, zero based
    * @param endIdx
    *        the component end index, zero based, exclusive. The end index is
    *        always greater than the start index.
    */
   protected void visitSeconds(final int startIdx, final int endIdx)
   {
      // no-op
   }

   /**
    * The milliseconds component of the date spec was parsed.
    * 
    * @param startIdx
    *        the component start index, zero based
    * @param endIdx
    *        the component end index, zero based, exclusive. The end index is
    *        always greater than the start index.
    */
   protected void visitMilliseconds(final int startIdx, final int endIdx)
   {
      // no-op
   }

   /**
    * The AM component of the date spec was parsed.
    * 
    * @param startIdx
    *        the component start index, zero based
    * @param endIdx
    *        the component end index, zero based, exclusive. The end index is
    *        always greater than the start index.
    */
   protected void visitAMPM(final int startIdx, final int endIdx)
   {
      // no-op
   }

   /**
    * The hours in timezone component of the date spec was parsed.
    * 
    * @param startIdx
    *        the component start index, zero based
    * @param endIdx
    *        the component end index, zero based, exclusive. The end index is
    *        always greater than the start index.
    */
   protected void visitTZHours(final int startIdx, final int endIdx)
   {
      // no-op
   }

   /**
    * The minutes in timezone component of the date spec was parsed.
    * 
    * @param startIdx
    *        the component start index, zero based
    * @param endIdx
    *        the component end index, zero based, exclusive. The end index is
    *        always greater than the start index.
    */
   protected void visitTZMinutes(final int startIdx, final int endIdx)
   {
      // no-op
   }

   /**
    * Parse datetime format, call callbacks while parsing.
    * 
    * @throws ErrorConditionException
    *         in case the date format is invalid
    */
   @Override
   public void parse(final String format) throws ErrorConditionException
   {
      // date & time separator is now space
      final String fmt = format.replace('t', ' ').replace('T', ' ').toUpperCase();
      final int len = fmt.length();

      // split date and time parts
      final int dateTimeSepIdx = fmt.indexOf(' ');
      final boolean dateSpecOnly = dateTimeSepIdx == -1;
      int dateTimeCompOrderIndex = 0;

      final byte[] datetimeCompOrder = new byte[10];
      final byte[] dateCompOrder = date.getDateComponentOrder();
      datetimeCompOrder[dateTimeCompOrderIndex++] = dateCompOrder[0];
      datetimeCompOrder[dateTimeCompOrderIndex++] = dateCompOrder[1];
      datetimeCompOrder[dateTimeCompOrderIndex++] = dateCompOrder[2];
      for (int i = 3; i < datetimeCompOrder.length; i++)
      {
         datetimeCompOrder[i] = -1;
      }

      super.parse(dateSpecOnly ? format : fmt.substring(0, dateTimeSepIdx));
      if (dateSpecOnly)
      {
         return;
      }

      int idx = dateTimeSepIdx;

      // Skip a single allowed 't' character after the date part.
      switch (format.charAt(idx))
      {
         case 't':
         case 'T':
            idx++;
            break;
         default:
      }

      // Skip any number of whitespaces
      while (idx < len && fmt.charAt(idx) == ' ')
      {
         ++idx;
      }

      if (idx == len)
      {
         // No time spec
         return;
      }

      // Count the number of 'S' characters in the rest of the format spec.
      if (fmt.chars().filter(ch -> ch == 'S').count() > 5)
      {
         ErrorManager.recordOrThrowError(14312,
                  String.format("Too many 'S' characters in format \"%s\"", fmt));
         return;
      }

      int sectionStart = idx;
      idx = parseComponent(this::visitHours, 'H', idx, fmt, len);

      if (idx > sectionStart)
      {
         if (idx == len)
         {
            return;
         }

         sectionStart = idx;
         if (fmt.charAt(idx) == ':')
         {
            idx++;
            idx = parseComponent(this::visitMinutes, 'M', idx, fmt, len);
            if (idx > sectionStart)
            {
               if (idx == len)
               {
                  return;
               }

               sectionStart = idx;
               if (fmt.charAt(idx) == ':')
               {
                  idx++;
                  idx = parseComponent(this::visitSeconds, 'S', idx, fmt, len);
                  if (idx > sectionStart)
                  {
                     if (idx == len)
                     {
                        return;
                     }

                     if (fmt.charAt(idx) == '.')
                     {
                        idx++;
                        sectionStart = idx;
                        idx = parseComponent(this::visitMilliseconds, 'S', idx, fmt, len);
                        if (idx > sectionStart)
                        {
                           if (idx == len)
                           {
                              return;
                           }
                        }
                     }
                  }
               }
            }
         }

         // Skip any number of whitespaces
         while (idx < len && fmt.charAt(idx) == ' ')
         {
            ++idx;
         }

         if (idx == len)
         {
            return;
         }

         if (fmt.charAt(idx) == 'A')
         {
            sectionStart = idx;
            idx++;
            if (idx < len && fmt.charAt(idx) == 'M')
            {
               idx++;
            }
            visitAMPM(sectionStart, idx);
         }
      }

      if (idx == len)
      {
         return;
      }

      // Parse optional TZ part
      switch (fmt.charAt(idx))
      {
         case '+':
         case '-':
            idx++;
            sectionStart = idx;
            int k = idx;
            for (; k < len && fmt.charAt(k) == 'H'; k++)
               ;

            if (k > sectionStart)
            {
               // Note: the leading +/- character belongs to the component.
               visitTZHours(sectionStart - 1, k);
            }
            idx = k;

            if (idx > sectionStart)
            {
               if (idx == len)
               {
                  return;
               }
               if (fmt.charAt(idx) == ':')
               {
                  idx++;
                  sectionStart = idx;
                  idx = parseComponent(this::visitTZMinutes, 'M', idx, fmt, len);
               }
            }
      }

      // Skip any number of trailing whitespaces
      while (idx < len && fmt.charAt(idx) == ' ')
      {
         ++idx;
      }

      if (idx < len)
      {
         ErrorManager.genInvalidCharError(idx, format);
         return;
      }
   }

   /**
    * Parse one format component.
    * 
    * @param cb
    *        the callback to call
    * @param c
    *        the character to skip, in upper case
    * @param fromIdx
    *        start index
    * @param fmt
    *        format string
    * @param len
    *        format length
    * @return the resulting index
    */
   private final static int parseComponent(final Callback cb, final char c, final int fromIdx,
            final String fmt, final int len)
   {
      // Note: when parsing format, OE accepts ANY number of letter for in any part of time spec.
      int i = fromIdx;
      for (; i < len && Character.toUpperCase(fmt.charAt(i)) == c; i++)
         ;

      if (i > fromIdx)
      {
         cb.call(fromIdx, i);
      }

      return i;
   }

   /**
    * Helper interface used to describe for all component callbacks
    *
    */
   private static interface Callback
   {
      void call(final int startIdx, final int endIdx);
   }

}