UniqueIndexLookup.java

/*
** Module   : UniqueIndexLookup.java
** Abstract : Container for properties and values used when doing a unique index look-up.
**
** Copyright (c) 2023, Golden Code Development Corporation.
**
** -#- -I- --Date-- -----------------------------------Description-----------------------------------
** 001 AL2 20230210 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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**     name Golden Code, FWD, or the names of any author or contributor, for
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*/

package com.goldencode.p2j.persist;

import java.util.ArrayList;
import java.util.List;

/**
 * Utility class which stores the properties and values of a look-up which is done 
 * over an unique index. 
 */
public class UniqueIndexLookup
{
   /** The properties of the unique index, not necessarily in order */
   private List<String> properties;
   
   /** 
    * The values used for look-up; the order matched the order of the properties
    * A null value means a value that is provided latter (by substitution parameters).
    */
   private List<Object> values;

   /**
    * Basic constructor
    */
   public UniqueIndexLookup()
   {
      properties = new ArrayList<>();
      values = new ArrayList<>();
   }
   
   /**
    * Copy constructor
    * 
    * @param  prototype
    *         The prototype to be used when building this object.
    */
   public UniqueIndexLookup(UniqueIndexLookup prototype)
   {
      this.properties = new ArrayList<>(prototype.properties);
      // deep copy is not needed; values are immutable
      this.values = new ArrayList<>(prototype.values);
   }
   
   /**
    * Fill the {@code null} values from the values array with the provided fill values.
    * This is used to lazily add the substitution parameters when needed. 
    * 
    * @param   fillValues
    *          The values to be used when filling the parameters array.
    *          
    * @return  {@code true} if the filling succeeded. If this returns {@code false}, the 
    *          object reaches a stale state, so avoid using it.
    */
   public boolean fill(Object[] fillValues)
   {
      int from = 0;
      for (int i = 0; i < this.values.size(); i++)
      {
         if (this.values.get(i) == null)
         {
            if (fillValues == null || fillValues.length <= from)
            {
               return false;
            }
            this.values.set(i, fillValues[from++]);
         }
      }
      if (fillValues == null)
      {
         return from == 0;
      }
      return from == fillValues.length;
   }

   /** 
    * Add a new property-value mapping to this look-up.
    * 
    * @param   property
    *          The property from an unique index.
    * @param   value
    *          The value to be used when doing look-up.
    */
   public void addMapping(String property, Object value)
   {
      properties.add(property);
      values.add(value);
   }

   /**
    * Retrieve the properties as an array.
    * 
    * @return   The array of properties.
    */
   public String[] getProperties()
   {
      return properties.toArray(new String[0]);
   }
   
   /**
    * Retrieve the values as an array.
    * 
    * @return   The array of values.
    */
   public Object[] getValues()
   {
      return values.toArray();
   }
   
}