Element.java

/*
** Module   : Element.java
** Abstract : Abstract database element representation for database schema storage and comparison.
**
** Copyright (c) 2022, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------------Description---------------------------------------
** 001 BS  20221103 Created initial version.
*/

/*
** 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
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*/

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

import java.util.*;

/**
 * Abstract database element representation. Tables, Attributes and Indexes all extend this class.
 */
public abstract class Element
{
   /**
    * Parent of the element. Table for indexes and columns, null for tables.
    */
   private final Table table;
   
   /**
    * Most basic property of any element - it's name.
    */
   private final String name;
   
   /**
    * Comment for the element.
    */
   private final String comment;
   
   /**
    * Default constructor.
    *
    * @param   name
    *          Most basic property of any element - it's name
    * @param   comment
    *          Comment for the element
    */
   protected Element(String name, String comment)
   {
      this(name, null, comment);
   }
   
   /**
    * Default constructor.
    *
    * @param   name
    *          Most basic property of any element - it's name
    * @param   table
    *          Table containing the element (parent)
    * @param   comment
    *          Comment for the element
    */
   protected Element(String name, Table table, String comment)
   {
      this.table = table;
      this.name = name;
      this.comment = comment;
   }
   
   /**
    * Getter for table.
    *
    * @return Parent of the element. Table for indexes and columns, null for tables.
    */
   public Table getTable()
   {
      return table;
   }
   
   /**
    * Getter for name
    *
    * @return Most basic property of any element - its name.
    */
   public String getName()
   {
      return name;
   }
   
   /**
    * Getter for comment.
    *
    * @return Comment for the column
    */
   public String getComment()
   {
      return comment;
   }
   
   /**
    * Equals override uses name as a basic identifier.
    * This makes it easy to compare different elements in collections.
    */
   @Override
   public boolean equals(Object o)
   {
      if (this == o)
         return true;
      if (o == null || getClass() != o.getClass())
         return false;
      Element element = (Element) o;
      return name.equals(element.name);
   }
   
   /**
    * Hashcode override uses name as a basic identifier.
    * This makes it easy to compare different elements in collections.
    */
   @Override
   public int hashCode()
   {
      return Objects.hash(name);
   }
}