CharacterFormatter.java

/*
** Module   : CharacterFormatter.java
** Abstract : Implements the Progress STRING(value, format) function for characters.
**
** Copyright (c) 2019-2023, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------Description---------------------------------
** 001 VVT 20210408 Created initial version.
**     VVT 20210427 API changed: the format is now passed to class constructor.
**                  Method parse() renamed to format()
** 002 GBB 20230512 Logging methods replaced by CentralLogger/ConversionStatus.
*/
/*
** 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
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**     name Golden Code, FWD, or the names of any author or contributor, for
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**     versions of the covered work must be marked in a reasonable way to make it
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**     attribution required in this license.
*/
package com.goldencode.p2j.util;

import com.goldencode.p2j.util.logging.*;

import java.io.*;

/**
 * Implements the Progress <code>STRING(value, format)</code> function
 * for characters.
 * <p>
 * Example:
 * <p>
 * <pre>
 * CharacterFormatter formatter = new CharacterFormatter("String to format", "x(8)");
 * formatter.parse();
 * String formatted = formatter.getValue(); // "String t"
 * </pre>
 *
 */
public class CharacterFormatter extends CharacterFormatParser
{
   /** Logger */
   private static final CentralLogger LOG = CentralLogger.get(CharacterFormatter.class);
   
   /** The input format specification */
   protected final String format;

   /** The collector for the output formatted value */
   private final StringBuilder out = new StringBuilder();

   /** Reader on the input formatted string */
   private final Reader in;

   /**
    * The constructor.
    *  
    * @param format
    *        the format string
    * @param value
    *        the value to format
    */
   public CharacterFormatter(final String format, final String value)
   {
      this.format = format;
      in = new StringReader(value);
   }

   /**
    * Get the formatted value.
    * 
    * @return see above
    */
   public String getValue()
   {
      return out.toString();
   }

   /**
    * Do the formatting.
    * 
    * @return the formatted string.
    */
   public String format()
   {
      parse(format);
      return out.toString();
   }

   /**
    * This method is called by {@link #format()} for each occurrence of
    * a non-special character in format string.
    * 
    * @param ch
    *        the format character
    */
   @Override
   protected void visitFillChar(final char ch)
   {
      out.append(ch);
   }

   /**
    * This method is called by {@link #format()} for each occurrence of
    * the 'a' (letter) special character in format string.
    * 
    * @param repeatCount
    *        the special character repeat count
    */
   @Override
   protected void visitLetter(final int repeatCount)
   {
      processCharactersAsIs(repeatCount);
   }

   /**
    * This method is called by {@link #format()} for each occurrence of
    * the 'n' (alphanumeric) special character in format string.
    * 
    * @param repeatCount
    *        the special character repeat count
    */
   @Override
   protected void visitAlphanum(final int repeatCount)
   {
      processCharactersAsIs(repeatCount);
   }

   /**
    * This method is called by {@link #format()} for each occurrence of
    * the 'x' (any character) special character in format string.
    * 
    * @param repeatCount
    *        the special character repeat count 
    */
   @Override
   protected void visitAnyChar(final int repeatCount)
   {
      processCharactersAsIs(repeatCount);
   }

   /**
    * This method is called by {@link #format()} for each occurrence of
    * the '9' (the digit) special character in format string.
    * 
    * @param repeatCount
    *        the special character repeat count
    */
   @Override
   protected void visitDigit(final int repeatCount)
   {
      processCharactersAsIs(repeatCount);
   }

   /**
    * This method is called by {@link #format()} for each occurrence of
    * the '!' (upcase) special character in format string.
    * 
    * @param repeatCount
    *        the special character repeat count
    */
   @Override
   protected void visitUpperLetter(final int repeatCount)
   {
      processCharacters(Character::toUpperCase, repeatCount);
   }

   /**
    * Process characters with no conversion helper method.
    * 
    * @param repeatCount
    *        the character repeat count 
    */
   private final void processCharactersAsIs(int repeatCount)
   {
      processCharacters(c -> c, repeatCount);
   }

   /**
    * Process the action associated with a special formatting character.
    * 
    * @param converter
    *        the character converter
    * @param repeatCount
    *        the number of times the operation should repeat
    */
   private final void processCharacters(final Convert converter, final int repeatCount)
   {
      try
      {
         for (int i = 0; i < repeatCount; i++)
         {
            final int read = in.read();
            if (read == -1)
            {
               // No more input characters, pad with spaces
               out.append(' ');
               continue;
            }

            out.append(converter.convert((char) read));
         }
      }
      catch (IOException e)
      {
         // Should never happen when reading from a string
         LOG.severe("", e);
      }
   }

   /**
    * Helper method for character testers.
    *
    */
   private static interface Convert
   {
      /**
       * Convert a character.
       * 
       * @param c
       *        the character to test
       *        
       * @return the result of conversion
       */
      char convert(char c);
   }
}