CharacterType.java

/*
** Module   : CharacterType.java
** Abstract : Handles conversion from/to SQL/FWD character type.
**
** Copyright (c) 2019-2024, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------------Description---------------------------------------
** 001 OM  20191101 Created initial version.
** 002 ECF 20200919 Performance: removed use of ResultSet.wasNull. ResultSet.getString already returns null
**                  in the case of SQL NULL.
**     OM  20221117 Some properties (datetime-tz) may take a different number of positional parameters when
**                  used in insert/update or where predicate.
** 003 TJD 20240123 Java 17 compatibility updates
*/

/*
** 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:
**
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**   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.
**
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*/

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

import com.goldencode.p2j.persist.Record;
import com.goldencode.p2j.persist.orm.*;
import com.goldencode.p2j.util.*;
import java.sql.*;

/** This object handles conversion from/to SQL/FWD {@code character} type. */
public class CharacterType
implements DataHandler
{
   /**
    * Creates and returns a new {@link character} from a SQL counterpart.
    *  
    * @param   sqlVal
    *          A value obtained from a SQL query, which needs to be converted to a 
    *          {@code BaseDataType}. 
    *
    * @return  A FWD {@code character} object representing the same value as {@code sqlVal}.
    */
   @Override
   public character convert(Object sqlVal)
   {
      return new character((String) sqlVal);
   }
   
   /**
    * Use the data from a {@link character} field stored in {@code BaseRecord.data} and use it
    * to initialize a parameter of type SQL character in a SQL prepared query.
    *
    * @param   stmt
    *          The prepared statement whose parameter is to be set.
    * @param   index
    *          The index/position of the parameter.
    * @param   val
    *          The value of the parameter. Must be a {@code character}.
    * @param   forUpdate
    *          {@code true} if the parameter in the statement is used to update a field and {@code false} if
    *          it is used as part of the where predicate. Ignored here.
    *
    * @return  1 (the number of position used by this value).
    * 
    * @throws  SQLException
    *          when an error is encountered while setting the value.
    */
   @Override
   public int setParameter(PreparedStatement stmt, int index, Object val, boolean forUpdate)
   throws SQLException
   {
      return TypeManager.setStringParameter(stmt, index, val, forUpdate);
   }
   
   /**
    * 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  always 1.
    *
    * @throws  SQLException
    *          when an error is encountered while setting the value.
    */
   @Override
   public int readProperty(ResultSet rs, int rsOffset, Object[] data, int propIndex)
   throws SQLException
   {
      data[propIndex] = rs.getString(rsOffset);
      
      return 1;
   }
   
   /**
    * Instantiate a low-level initial value suitable for storage in a {@link BaseRecord}'s data
    * array, parsed from a string representation.
    * 
    * @param   text
    *          String representation of the initial value.
    * @param   meta
    *          Property metadata.
    */
   @Override
   public Object initialValue(String text, PropertyMeta meta)
   {
      return new character(text).toJavaType();
   }
   
   /**
    * Compute the size in bytes taken by a specified value for the data type handled by this
    * class. The returned value is used to compute the index size.
    *
    * @param   val
    *          The value to be computed the size. Assumed to be a {@code String}.
    *
    * @return  the number of bytes the {@code val} object occupies.
    */
   @Override
   public int getFieldSizeInIndex(Object val)
   {
      if (val == null)
      {
         return 3;
      }
      
      // TODO: investigate multibyte texts
      int len = ((String) val).length();
      return (len == 0) ? 2 : 1 + len;
   }
   
   /**
    * Sets a value of a property in a {@code Record}. The specified value is converted from
    * {@code BaseDataType} FWD standard to plain Java, as the {@code data} array expects before
    * assigning the value to right offset.
    *
    * @param   data
    *          The {@code data} array of the record to be altered.
    * @param   val
    *          The {@code BaseDataType} value to be set. Assumed to be a {@code character}.
    * @param   offset
    *          The offset of the property, ie, the entry in {@code data} array. This includes both
    *          base property offset and the eventual extent index.
    * @param   meta
    *          Property metadata. Used to fine-tune stored data. 
    */
   @Override
   public void setField(Object[] data, BaseDataType val, int offset, PropertyMeta meta)
   {
      if (val == null || val.isUnknown())
      {
         data[offset] = null;
         return;
      }
      
      character asBDT = (character) val;
      data[offset] = asBDT.toJavaType();
   }
   
   /**
    * Obtain the value of the property of a {@code Record} located at a specified offset in {@code data}
    * array. It assumes the data at specified offset is compatible with this data handler. 
    *
    * @param   r
    *          The {@code Record}.
    * @param   offset
    *          The offset.
    *
    * @return  The value requested wrapped as a {@code BaseDataType}.
    */
   @Override
   public BaseDataType getField(Record r, int offset)
   {
      return r._getCharacter(offset);
   }
}