MariaDbHelper.java

/*
** Module   : MariaDbHelper.java
** Abstract : Helper class which initializes MariaDb database.
**
** Copyright (c) 2022-2024, Golden Code Development Corporation.
**
** -#- -I- --Date-- -------------------------------------- Description --------------------------------------
** 001 OM  20120816 Created initial version. Helper class which provides utilities for MariaDb.
**     OM  20221103 New class names for FQLPreprocessor, FQLExpression, FQLBundle, and FQLCache.
** 002 DDF 20240411 Added org.h2.value.ValueTimestampTimeZone to available decorations for datetime-tz.
*/

/*
** 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.persist.dialect;

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

import java.lang.reflect.*;
import java.util.*;

/**
 * Helper class which provides MariaDb - specific services:
 * <ul>
 *    <li>gather HQL/SQL functions
 *    <li>decorate them to avoid the overloading restriction of the server
 * </ul>
 */
public final class MariaDbHelper
{
   /**
    * Private constructor. All access to this class is via static methods.
    */
   private MariaDbHelper()
   {
   }
   
   /**
    * Register the function aliases with the HQL preprocessor, for the permanent database.
    *
    * @param   database
    *          Database to prepare.
    */
   public static void registerOverloadedFunctions(Database database)
   {
      registerOverloadedFunctions(database, BuiltIns.getPublicFunctions());
      registerOverloadedFunctions(database, BuiltIns.getSupportFunctions());
   }
   
   /**
    * Get function aliases for the given list of static methods, optionally making the alias names
    * unique by appending parameter type decorations.
    *
    * @param   database
    *          Database in which to create aliases.
    * @param   funcs
    *          List of static methods for which function aliases should be created.
    */
   private static void registerOverloadedFunctions(Database database, List<Method> funcs)
   {
      for (Method method : funcs)
      {
         HQLFunction hqlFn = method.getAnnotation(HQLFunction.class);
         if (hqlFn == null)
         {
            // not a support function
            continue;
         }
         
         String hqlName = hqlFn.name().isEmpty() ? method.getName() : hqlFn.name();
         StringBuilder sb = new StringBuilder(hqlName);
         boolean hasAny = false;
         
         Class<?>[] signature = method.getParameterTypes();
         for (Class<?> aClass : signature)
         {
            if (!hasAny)
            {
               hasAny = true;
               sb.append("_");
            }
            sb.append(getSqlDecoration(aClass.getName()));
         }
         
         FQLPreprocessor.registerFunction(database, hqlName, sb.toString().toLowerCase(), method);
      }
   }
   
   /**
    * Returns the parameter decoration for fixing the function overloading constraint in MariaDb.
    *
    * @param   javaType
    *          The java type (full name).
    *
    * @return  a character for decorating the SQL function.
    */
   private static char getSqlDecoration(String javaType)
   {
      switch (javaType)
      {
         case "java.lang.Boolean":
         case "boolean":
            return 'B';
            
         case "java.lang.Integer":
         case "int":
         case "integer":
            return 'I';
            
         case "java.lang.Long":
         case "long":
         case "bigint":
            return 'L';
            
         case "java.lang.String":
         case "text":
            return 'T';
            
         case "java.math.BigDecimal":
         case "numeric":
            return 'N';
            
         case "java.sql.Date":
         case "date":
            return 'D';
            
         case "java.sql.Timestamp":
         case "timestamp without time zone":
            return 'S';
            
         case "org.h2.value.ValueTimestampTimeZone":
         case "time without time zone":
         case "time":
            return 'M';
            
         case "udf.time_format":
         case "JSON":
            return 'F';
      }
      
      return ' ';
   }
}