How to make @Cacheable return null when not found in cache but do not cache the result?

Question

Following @Cacheable annotation

@Cacheable(value="books", key="#isbn")
public Book findBook(ISBN isbn, boolean checkWarehouse, boolean includeUsed)

looks up in the cache based on the key
if found return the result from cache
if not found evaluates method
updates the cache
return the result

So that next time this method is called with same arguments it will be fetched from cache.

What I want instead is just to

Look up in the cache based on key
if found return the result from cache
if not found return null

I don't want to update the cache in case of cache-miss, is there any way to do this using spring Annotation

This isn't really the use-case for the @Cacheable annotation, and it's not really a common use case at all, so I'd guess that no you can't do this with spring annotations, and that you'll have to write a findBookInCache(ISBN isbn) method yourself. — beerbajay

Prashant Bhate Prashant Bhate · Accepted Answer · 2015-04-23T13:00:15

Here is what I ended up with, trick was to use 'unless' to our advantage

@Cacheable(value="books", key="#isbn", unless = "#result == null")
public Book findBookFromCache(ISBN isbn, boolean checkWarehouse, boolean includeUsed)
{
    return null;
}

this method

Looks up in the cache based on key
if found return the result from cache
if not found evaluates method that return null
return value is matched with unless condition (which always return true)
null value do not get cached
null value is returned to caller

How to make @Cacheable return null when not found in cache but do not cache the result?

1 Answers