LogicalType.java
/*
** Module : LogicalType.java
** Abstract : Handles conversion from/to SQL/FWD logical type.
**
** Copyright (c) 2019-2024, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------------Description---------------------------------------
** 001 OM 20191101 Created initial version.
** 002 ECF 20200919 Performance: use ResultSet.wasNull only if ResultSet.getBoolean returns ambiguous default
** value, which might represent SQL NULL.
** OM 20220303 Take into account the FORMAT when computing the initial value of logical fields.
** TJD 20221018 Allow initialization of Logical from empty string
** 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
*/
/*
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** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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**
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package com.goldencode.p2j.persist.orm.types;
import com.goldencode.p2j.persist.*;
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 logical} type. */
public class LogicalType
implements DataHandler
{
/**
* Creates and returns a new {@link logical} 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 logical} object representing the same value as {@code sqlVal}.
*/
@Override
public logical convert(Object sqlVal)
{
return new logical((Boolean) sqlVal);
}
/**
* Use the data from a {@link logical} field stored in {@code BaseRecord.data} and use it
* to initialize a parameter of type logical 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 logical}.
* @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.setBooleanParameter(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. I.e. the record's {@code data} field member.
* @param propIndex
* The destination offset. I.e. 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
{
boolean datum = rs.getBoolean(rsOffset);
data[propIndex] = !datum && rs.wasNull() ? null : datum;
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)
{
String fmt = meta.getFormat();
// empty text on initialization means initial value is not set, use default value
if ("".equals(text))
return new logical();
else
return new logical(text, fmt.isEmpty() ? logical.DEFAULT_FORMAT : fmt).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.
*
* @return the number of bytes the {@code val} object occupies.
*/
@Override
public int getFieldSizeInIndex(Object val)
{
return 3; // always 3, regardless of the 3 possible values: yes, no, or unknown
}
/**
* 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 logical}.
* @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;
}
logical asBDT = (logical) val;
data[offset] = asBDT.booleanValue();
}
/**
* 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._isLogical(offset);
}
}