SchemaValidator.java

/*
** Module   : SchemaValidator.java
** Abstract : Validates dynamically added tables and checks if they can be represented as an ORM.
**
** Copyright (c) 2022-2024, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------------Description---------------------------------------
** 001 BS  20221230 Created initial version.
** 002 BS  20230331 Added validations for sequences.
** 003 OM  20240412 Added sorting direction for index components.
** 004 OM  20240516 Throw StopConditionException() in the mutable database failed validation.
*/

/*
** 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.
**
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**     work or Appropriate Legal Notices displayed by works containing the covered
**     work.  You may not remove from the covered work any author or developer
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*/

package com.goldencode.p2j.persist.orm.schema;

import com.goldencode.p2j.persist.*;
import com.goldencode.p2j.persist.orm.*;
import com.goldencode.p2j.persist.orm.schema.element.*;
import com.goldencode.p2j.util.*;
import java.util.*;
import java.util.function.*;

/**
 * Validates dynamically added tables and checks if they can be represented as an ORM.
 */
public class SchemaValidator
{
   /**
    * Validation rules. Key is an error message, value is a runnable function that returns a validation result
    * as a boolean value.
    *
    * Validation function convention:
    *   <code>FALSE</code> means no violation
    *   <code>TRUE</code> means violation is detected, an error will be reported
    */
   private static final Map<String, Function<Table, Boolean>> RULES = new HashMap<>();
   
   /** Record ID (recid) column name. */
   public static final String RECID = Session.PK;
   
   static
   {
      RULES.put("Table {table} needs to have at least one attribute",
                table -> table.getAttributes().isEmpty());
      RULES.put("Surrogate primary key must be present. Table {table} needs to have a " + RECID + " column",
                table -> table.getAttributes().stream()
                              .noneMatch(attribute -> attribute.getName().equalsIgnoreCase(RECID)));
      RULES.put("Table {table} needs to have more columns than just " + RECID,
                table -> table.getAttributes().stream()
                              .allMatch(attribute -> attribute.getName().equalsIgnoreCase(RECID)));
      RULES.put("Table {table} has column " + RECID + " indexed incorrectly. " +
                "Column " + RECID + " can only appear at the end of the index.",
         table -> table.getIndexes().stream().anyMatch(index -> {
            List<Tuple<String, Boolean>> columns = index.getColumns();
            if (!columns.isEmpty())
            {
               boolean recidUsed = columns.stream().anyMatch(s -> s.getKey().equalsIgnoreCase(RECID));
               String lastColumnName = columns.get(columns.size() - 1).getKey();
               
               // RECID is indexed, but not at the end
               return recidUsed && !lastColumnName.equalsIgnoreCase(RECID);
            }
            // This should not happen (databases should not create indexes with no columns), but just in case.
            return false;
         })
      );
   }
   
   /**
    * Apply validation rules on given table.
    *
    * @param   table
    *          Table to validate
    *
    * @throws  ErrorConditionException
    *          Exception is thrown in case of a failed validation
    */
   public static void validate(Table table)
   throws ErrorConditionException
   {
      for (Map.Entry<String, Function<Table, Boolean>> entry : RULES.entrySet())
      {
         if (entry.getValue().apply(table))
         {
            throw new StopConditionException(entry.getKey().replace("{table}", table.getName()));
         }
      }
   }
   
   /**
    * Apply validation rules on sequences. Currently just check that p2j_id_generator_sequence exists.
    *
    * @param   sequences
    *          Sequence list to validate
    *
    * @throws  ErrorConditionException
    *          Exception is thrown in case of a failed validation
    */
   public static void validate(Collection<Sequence> sequences)
   throws ErrorConditionException
   {
      if (sequences.stream()
                   .noneMatch(sequence -> sequence.getName().equalsIgnoreCase(Persistence.ID_GEN_SEQUENCE)))
      {
         throw new StopConditionException(
               "Sequence " + Persistence.ID_GEN_SEQUENCE + " is not defined in database.");
      }
   }
}