I have the following model in MySQL:
```
{{ import com.vividsolutions.jts.geom.Point;
@Entity
@Table(name = "users")
public class User {
Integer age;
Point location;
} }}
```
Note that `age` is alphabetically before `location`. In Hibernate code, when extracting values from query results, `age` is processed first, then `location`, in alphabetically order.
If `age` is NULL in the database, then regardless of what the value of `location` in the database is, Hibernate **always** returns NULL for `location`. If I give `age` a non-NULL value, then Hibernate returns correct value, i.e. a valid Point, for `location`.
After some debugging, I found out that the bug occurs at the following lines of BasicExtractor:
``` @Override
public J extract(ResultSet rs, String name, WrapperOptions options) throws SQLException {
final J value = doExtract( rs, name, options );
final boolean traceEnabled = log.isTraceEnabled();
if ( value == null || rs.wasNull() ) {
...
return null;
}
```
The variable `value` was extracted correctly from the ResultSet. It's a Point object matching the data of `location` in the database. However, this Point object is discarded and NULL is returned because `rs.wasNull()` is `true`. It turns out, the flag rs.thisRow.wasNull is not set for column `location`. It still has the value of the previous column, i.e. `age`.
So, if `age` is NULL, then `location` will be set to NULL as well, although it has a valid non-NULL value.
The method which extracts the data for the Geometry column is in the class `MySQLGeometryTypeDescriptor` at the following line:
```
@Override
public <X> ValueExtractor<X> getExtractor(final JavaTypeDescriptor<X> javaTypeDescriptor) {
return new BasicExtractor<X>( javaTypeDescriptor, this ) {
@Override
protected X doExtract(ResultSet rs, String name, WrapperOptions options) throws SQLException {
return getJavaDescriptor().wrap( toGeometry( rs.getBytes( name ) ), options );
}
```
It doesn't set the flag rs.thisRow.wasNull after extraction, causing this bug. |
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