Description Sebastien Tardif 2008-08-12 18:14:56 EDT

Old Sequence behavior on "long id" by specifing null value in descriptor is broken by Rev 2000 under bug#220394 -improves insert performance.

I have an application that works in many previous version of TopLink.
However, on EclipseLink, it doesn't work anymore.

Most but not all of my domain objects use "long id" for mapped primary key. Default initialization in Java for long is 0. So our application 99% of all objects setup the mapping to tell that attribute "id"
"default null value" is Long == 0 using TopLink/EclipseLink workbench.

We do communicate to TopLink that id == 0 is equivalent to null but the new sequence code doesn't care anymore about what we specify. We see the new code has removing a feature and making the Workbench "default null value" feature most of the time useless in our case. 

You probably already heard of the "Null Pattern". That's why we avoid using Long instead of "long". With Java 5 it's even worst, if we use Long and some client code expect "long" Java will do an implicit cast but at runtime will throw NullPointerException.

It looks weird from the client code that we call assignSequenceNumber when our sequence field in not explicitly initialized and the method refuse to assign the sequence.

I really doubt that that checking what is the definition of null in the descriptor for the field involved can be visible in a profiler.

The guilty method is: 

    public Object assignSequenceNumber(Object object, AbstractSession
writeSession) throws DatabaseException {
        DatabaseField sequenceNumberField = this.descriptor.getSequenceNumberField();
        Object existingValue = getBaseValueForField(sequenceNumberField,
object);
        // If the value is null or zero (int/long) return.
        // PERF: The (internal) support for letting the sequence decide this was removed,
        // as anything other than primitive should allow null and default as such.
        if (existingValue != null &&
!Helper.isEquivalentToNull(existingValue)) {
            return null;
        }

   /**
     * Check if the value is null, or 0 (int/long) for primitive ids.
     */
    public static boolean isEquivalentToNull(Object value) {
        return (value == null)
                        || (!isZeroValidPrimaryKey
                                && (((value.getClass() ==
ClassConstants.LONG) && (((Long)value).longValue() == 0L))
                                        || ((value.getClass() ==
ClassConstants.INTEGER) && (((Integer)value).intValue() == 0))));
    }

https://bugs.eclipse.org/bugs/show_bug.cgi?id=233247