Columns can contain many types of data. This topic discusses storing Java objects in a Column. Columns are introducted more completely in "Working with columns" at the beginning of this chapter.
Fields in a SQL table, reported by JDBC as being of type java.sql.Types.OTHER, are mapped into columns whose data type isVariant.OBJECT, or you can set a column's data type to Object and set/get values through the normal data set API.
If a DataStore is used, the objects must be serializable. If they are not, an exception is raised whenever the DataStore attempts to save the object. Also, the class must exist on the CLASSPATH when it attempts to read an object. If not, the attempt will fail.
To format and edit a column that contains a Java object:
In the UI Designer, a formatter is assigned to Object columns by default. When the object is edited, it will simply be an object of type java.lang.String regardless of what the type was originally.
You can, and probably will want to, define the formatter property on a column to override the default functionality, or at least make the column non-editable. You can use a custom formatter to define the proper formatting and parsing of the objects kept in the column.
A column formatter is used for all the records in the data set. The implication of this is that you cannot mix object types in a particular column. This restriction is only for customized editing