[SIS-441] UnconvertibleObjectException when reading code list value from PostgreSQL

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.8
• Fix Version/s: 1.0
• Component/s: Metadata
• Assignee: Martin Desruisseaux
• Reporter: Martin Desruisseaux
• Created: 26/Nov/18 11:34
• Updated: 20/Oct/19 19:28
• Resolved: 26/Nov/18 11:34

Description

When metadata are read from database using org.apache.sis.sql.MetadataSource, an attempt to get the CodeList value of a metadata entry produce the following error:

org.apache.sis.util.collection.BackingStoreException: Database error while creating a ‘Role’ object for the “IOGP” identifier.
     at org.apache.sis.metadata.sql.Dispatcher.invoke(Dispatcher.java:161)
     at org.apache.sis.metadata.sql.$Proxy233.getRole(Unknown Source)
     (…snip…)
 Caused by: org.apache.sis.metadata.sql.MetadataStoreException: Expected an instance of ‘Role’ for the “role” property, but got an instance of ‘PGobject’.
     at org.apache.sis.metadata.sql.MetadataSource.readColumn(MetadataSource.java:990)
     at org.apache.sis.metadata.sql.Dispatcher.fetchValue(Dispatcher.java:227)
     at org.apache.sis.metadata.sql.Dispatcher.invoke(Dispatcher.java:159)
 Caused by: org.apache.sis.util.UnconvertibleObjectException: Can not convert from type ‘PGobject’ to type ‘Role’.
     at org.apache.sis.internal.converter.ConverterRegistry.find(ConverterRegistry.java:528)
     (…snip…)

This happen only with PostgreSQL database, because we store metadata as `VARCHAR` on Derby. The workaround is to read CodeList value using ResultSet.getString(int) instead than ResultSet.getObject(…), so the PGobject is converted to a String that we can later parse as a CodeList.