[SLING-8758] Add Adaptable method with a non-null return value

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Duplicate
• Component/s: API
• Assignee: Unassigned
• Reporter: Robert Munteanu
• Created: 02/Oct/19 12:49
• Updated: 13/Nov/19 15:50
• Resolved: 02/Oct/19 21:01

Description

We have had long-standing discussions about the fact that adaptTo returning null can lead to many hard-to-trace bugs.

One option of evolving the API is to add a default method to the adaptable which returns an optional

    default @NotNull <AdapterType> Optional<AdapterType> tryAdapt(@NotNull Class<AdapterType> type) {
        return Optional.ofNullable(adaptTo(type));
    }

This can in turn be used by clients to check that the adaption succeeed in a more fluent way

MyAdapted resource = resource.tryAdapt(MyAdapted.class)
            .orElseThrow( () -> new RuntimeException("Adaption failed") )
            .get();

or enable functional API usage patterns

MyAdapted resource = resource.tryAdapt(MyAdapted.class)
        .ifPresent( a ->  consume(a) );

Issue Links

• duplicates: SLING-3714 Allow for a caller to request a non-null response from adaptTo()
• relates to: SLING-3714 Allow for a caller to request a non-null response from adaptTo()
• relates to: SLING-3709 Sling Models: Allow caller to deal with exceptions