PropertyReader.java

/*
** Module   : PropertyReader.java
** Abstract : Functional interface for reading a (possibly multiple column) property from a SQL
**            result set.
**
** Copyright (c) 2020-2022, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------Description---------------------------------
** 001 OM  20200212 Created initial version.
** 002 CA  20221109 Added 'propertySize' method which returns the number of columns in the result-set for this
**                  property type.
*/

/*
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** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
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** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
** GNU Affero General Public License for more details.
**
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**
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**
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*/

package com.goldencode.p2j.persist.orm;

import java.sql.*;

/**
 * This functional interface exposes a method for reading a (possibly multiple column) property
 * from a SQL result set.
 */
@FunctionalInterface
public interface PropertyReader
{
   /**
    * Reads data from one or more positions from the {@code ResultSet}, eventually converting it
    * to a proper type and storing the result directly to the {@code Record}'s data structure.
    * 
    * @param   rs
    *          The {@code ResultSet} to read from. 
    * @param   rsOffset
    *          The index/position in current row of {@code rs} to start reading.
    * @param   data
    *          The destination. Ie. the record's {@code data} field member.
    * @param   propIndex
    *          The destination offset. Ie. the property index.
    *
    * @return  the number of positions read for this property to be fully read.
    *
    * @throws  SQLException
    *          when an error is encountered while setting the value.
    */
   public int readProperty(ResultSet rs, int rsOffset, Object[] data, int propIndex)
   throws SQLException;
   
   /**
    * Get the size (number of columns in the result-set) required by this property.
    * 
    * @return   Defaults to 1.
    */
   public default int propertySize()
   {
      return 1;
   }
}