Null-values are not cacheable

[ydewit]

We have a service that returns null as a value, but it seems that EnhancedTransactionAwareCacheDecorator is treating that explicitly set as deleted in the code below:

    public ValueWrapper get(@NonNull final Object key)
    {
        final TransientCacheData tcd = tcd();
        final ValueWrapper res = tcd.getTransientCache().get(key);
        if (res != null && isNull(res))
        {
            // Was explicitly set as deleted
            return null;
        }

Returning Optional instead will also not work since Spring Cache unwraps it.

The end result is that we are seeing repeated calls to the underlying storage.

[ethlo]

Hi!

Would it not work to use a null-placeholder in the cache?

Something like

        // Put somewhere static
        final Object nullObject = new Object();

        //mockTxnManager(true);
        //assertThat(TransactionSynchronizationManager.isSynchronizationActive()).isEqualTo(true);
        decoratorA.put("foo", nullObject);
        
        //assertThat(decoratorA.get("foo", Object.class)).isEqualTo(nullObject);
        
        //mockTransactionEnd(true);
        
        assertThat(realCacheA).containsEntry("foo", nullObject);

[ydewit]

That is the current workaround, but that means changing dozens of services. Ideally, I would expect the decorator to avoid changing the semantics of the caching provider.

[ethlo]

Ok, will look into what this may entail. What provider do you use?

[ydewit]

We use Ehcache.

[ethlo]

I have just released version 1.0.3 with the new fixes. Please confirm whether this fixes the issue.

[ydewit]

We had no time to validate, but I'll drop a note once we do.