# DialectHelper.java

    /*
    ** Module   : DialectHelper.java
    ** Abstract : A helper to P2J dialect classes
    **
    ** Copyright (c) 2014-2022, Golden Code Development Corporation.
    **
    ** -#- -I- --Date-- ---------------------------------Description---------------------------------
    ** 001 VMN 20131012 Created initial version.
    ** 002 OM  20140410 Fixed support case-sensitive fields in indexes.
    ** 003 OM  20150525 Added static method getDialectClass().
    ** 004 ECF 20200906 New ORM implementation.
    ** 005 IAS 20201219 Added support for "sqlserver2008" dialect.
    **     OM  20220721 Added partial conversion-time MariaDb dialect support.
    **     OM  20221018 Added support for MariaDb lenient dialect.
    */

    /*
    ** 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
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    **
    **     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
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    **     Corporation or FWD.  All modified versions must contain the notices of
    **     attribution required in this license.
    */

    package com.goldencode.p2j.persist.dialect;

    import java.net.*;
    import java.util.regex.*;

    import com.goldencode.p2j.convert.*;
    import com.goldencode.p2j.persist.*;

    /**
     * A helper to P2J dialect classes. This class provides static helper methods and constants used
     * for FWD dialects.
     */
    public class DialectHelper
    {
       /**
        * Common prefix prepended to computed column/property names. Additional decoration will be added
        * in order to identify columns that maps case sensitive fields.
        */
       static final String CC_PREFIX = "__";

       /** Signature for case-insensitive character column/property names */
       public static final String INSENSITIVE_CHAR_FIELD = CC_PREFIX + "i";

       /** Signature for case-sensitive character column/property names */
       public static final String SENSITIVE_CHAR_FIELD   = CC_PREFIX + "s";

       /** Double quote character */
       public static final char DOUBLE_QUOTE = '"';

       private static final Pattern TYPE_PATTERN = Pattern.compile("\\s*type:\\s*(.*)", Pattern.CASE_INSENSITIVE);

       private static final Pattern CASE_PATTERN = Pattern.compile("\\s*case-sensitive:\\s*(.*)", Pattern.CASE_INSENSITIVE);

       // All known patterns should be matched here
       private static final Pattern CLEAN_PATTERN = Pattern.compile("\\s*(case-sensitive|type):.*", Pattern.CASE_INSENSITIVE);

       /**
        * Build the URL to be used for a remote connection, based on the given URL and database.
        *
        * @param   url
        *          The URL as received from the remote server.
        * @param   database
        *          The database to which this URL belongs.
        *
        * @return  The built URL as to be used for a remote connection.
        *
        * @throws  PersistenceException
        *          if the specified connection URL is invalid.
        */
       public static String buildRemoteURL(String url, Database database)
       throws PersistenceException
       {
          String origUrl = url;
          try
          {
             url = url.substring("jdbc:".length());
             URI uri = (new URI(url)).normalize();

             // check for localhost references.
             String host = uri.getHost().toLowerCase();
             if (InetAddress.getByName(host).isLoopbackAddress())
             {
                // use hostname stored in database object.
                host = database.getSocketAddress().getHostName();

                // generate new URI.
                uri = new URI(uri.getScheme(),
                              uri.getUserInfo(),
                              host,
                              uri.getPort(),
                              uri.getPath(),
                              uri.getQuery(),
                              uri.getFragment());

                // prepend 'jdbc:' prefix.
                url = "jdbc:" + uri;
             }
             else
             {
                // no preparation is needed
                url = origUrl;
             }
          }
          catch (Exception exc)
          {
             throw new PersistenceException("Invalid database connection URL", exc);
          }

          return url;
       }

       /**
        * Return the Java class for a dialect using Hibernate identifier.
        *
        * @param   dialect
        *          The dialect name. Case insensitive.
        *
        * @return  The dialect class or {@code null} if the parameter does not match any known
        *          dialect identifier.
        */
       public static Class<? extends Dialect> getDialectClass(String dialect)
       {
          switch (dialect.toLowerCase())
          {
             case "h2":
                return P2JH2Dialect.class;
             case "postgresql":
                return P2JPostgreSQLDialect.class;
             case "sqlserver2012":
                return P2JSQLServer2012Dialect.class;
             case "sqlserver2008":
                return P2JSQLServer2008Dialect.class;
             case MariaDbDialect.DIALECT_ID:
                return MariaDbDialect.class;
             case MariaDbLenientDialect.DIALECT_ID:
                return MariaDbLenientDialect.class;
             default:
                return null;
          }
       }

       /**
        * Parsing type hints in column comments.
        *
        * @param   comment
        *          column comment as provided by JDBC
        * @return  matched type or null
        */
       protected static ParmType getParmTypeFromComment(String comment)
       {
          if (comment != null && !comment.isEmpty())
          {
             Matcher matcher = TYPE_PATTERN.matcher(comment);
             if (matcher.find())
             {
                String group = matcher.group(1);
                return ParmType.fromString(group);
             }
          }
          return null;
       }

       /**
        * Parsing case sensitivity hints in column comments.
        *
        * @param   comment
        *          column comment as provided by JDBC
        * @return  matched case sensitivity or false
        */
       public static boolean getCaseSensitive(String comment)
       {
          if (comment != null && !comment.isEmpty())
          {
             Matcher matcher = CASE_PATTERN.matcher(comment);
             if (matcher.find())
             {
                String group = matcher.group(1);
                return group.equalsIgnoreCase("TRUE") || group.equalsIgnoreCase("1");
             }
          }
          return false;
       }

       /**
        * Get column comment spared of all hints.
        *
        * @param   comment
        *          column comment as provided by JDBC
        * @return  clean column comment or null for empty comment
        */
       public static String getCleanComment(String comment)
       {
          if (comment != null && !comment.isEmpty())
          {
             Matcher matcher = CLEAN_PATTERN.matcher(comment);
             return matcher.replaceAll("");
          }
          return null;
       }
    }