BaseFwdCollator.java

/*
** Module   : BaseFwdCollator.java
** Abstract : An abstract class which implements the support for constructing collators for Progress-like
**            rules for all other code pages.
**
** Copyright (c) 2022, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------------Description---------------------------------------
** 001 OM  20220321 First revision pulling common code from existing collators at this time.
*/

/*
** 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
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**   Affero GPL version 3 and may not be removed by you.
** 
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*/

package com.goldencode.p2j.spi;

import java.io.*;
import java.text.*;

/**
 * The base class for a collator implementation using Progress-like rules for a specific character set.
 * <p>
 * Each code point in the character set is sorted uniquely and no allowances are made for varying collation
 * strength. There are no ignorable characters.
 */
public abstract class BaseFwdCollator
extends RuleBasedCollator
{
   /**
    * The constructor. This class is constructed from within this package by the {@link FwdCollatorProvider}.
    * 
    * @param   cpName
    *          The name of this code page.
    * @param   points
    *          An array of bytes representing the order in which the code-points will be sorted.
    * 
    * @throws  UnsupportedEncodingException
    *          if there is an error generating the rules.
    * @throws  ParseException
    *          if there is an error parsing the rules.
    */
   BaseFwdCollator(String cpName, int[] points)
   throws UnsupportedEncodingException,
          ParseException
   {
      super(initRules(cpName, points));
   }
   
   /**
    * Generate a rules string which governs Progress-like collation for the specific character set.
    *
    * @param   cpName
    *          The name of this code page.
    * @param   points
    *          An array of bytes representing the order in which the code-points will be sorted.
    *
    * @return  Rules string suitable for use by this rules-based collator.
    * 
    * @throws  UnsupportedEncodingException
    *          if the character encoding is unavailable.
    */
   private static String initRules(String cpName, int[] points)
   throws UnsupportedEncodingException
   {
      StringBuilder buf = new StringBuilder();
      for (int point : points)
      {
         // Assemble a rules string, according to the syntax required by the java.text.RuleBasedCollator
         // class.
         // It treats each code point as different and makes no allowances for varying collation strength.
         byte[] bytes = new byte[] {(byte) (point & 0xFF)};
         String s = new String(bytes, cpName);
         buf.append("< '").append(s).append("'");
      }
      return buf.toString();
   }
}