Re: Getting class to compile under JDK 1.5 AND 1.6

From:

Thomas Hawtin <usenet@tackline.plus.com>

Newsgroups:

comp.lang.java.programmer

Date:

Wed, 13 Dec 2006 23:34:03 +0000

Message-ID:

<45808d8f$0$8740$ed2619ec@ptn-nntp-reader02.plus.net>

Chris wrote:

The trouble is that one of our classes implements the java.sql.ResultSet
interface, and they changed the interface to include more methods. For
example:

The trouble is that now the code won't compile under JDK 1.5 because
RowId is a new class in 1.6 and doesn't exist in 1.5.

Welcome to JDBC interface changing hell.

The easiest solution: compile with 1.5 bootclasses (or java.sql
extracted from 1.5 and replacing 1.6 classes with -Xbootclasspath/p:).

If you want to compile on both platforms I suggest three source
directories: one directory containing common code (including an abstract
implementation of ResultSet), one directory containing the small amount
of 1.5 specific code and the last 1.6 code (using largely the same class
names as the 1.5 code). For 1.5 builds compile with the first two on the
sourcepath; for 1.6 use the first and last.

So:

In directory java:

package xx.example;

abstract class AbstractResultSet implements java.sql.ResultSet {
     ... constructors ...
     ... bulk of code ...
}
....
         ResultSetImpl results = new ResultSetImpl(...);

In directory java15:

package xx.example;

class ResultSetImpl extends AbstractResultSet {
     ... constructors ...
}

In directory java16:

package xx.example;

class ResultSetImpl extends AbstractResultSet {
     ... constructors ...
     public java.sql.RowId getRowId(int columnIndex) {
         throw new UnsupportedOperationException();
     }
     ... other JDBC 4.0 methods ...
}

Tom Hawtin