Prior to this commit, binding a `@ModelAttribute` object as a Controller
handler paramater would instantiate the object and set all its
properties, fetching data from the request. When no data is available,
the WebDataBinder tries to bind default "empty" values:
* Boolean.FALSE for boolean types
* empty arrays for array types
* null by default
This commit adds the new default empty values:
* empty Collections for Collection types
* empty Maps for Map types
Rather than using empty implementations provided by `Collections.empty`
(which are not mutable), we're using the closest possible target type
and real implementations, provided by the `CollectionFactory`.
Issue: SPR-13502
This commit introduces a boolean alwaysProcesses() method in the
Processor API which allows for simplification across all search
algorithms within AnnotatedElementUtils.
Specifically, it is no longer necessary for process() methods to verify
that the supplied annotation is actually the sought target annotation.
In addition, duplicated code has been extracted into common methods
(e.g., hasMetaAnnotationTypes()) and common Processor implementations
(e.g., AlwaysTrueBooleanAnnotationProcessor).
This commit picks up where 2535469099 left off with added support for
"get" search semantics for merged repeatable annotations.
Specifically, this commit introduces a new
getMergedRepeatableAnnotations() method in AnnotatedElementUtils.
Issue: SPR-13973
This commit picks up where a5139f3c66 left off with added support for
"get" search semantics for multiple merged annotations.
Specifically, this commit introduces a new getAllMergedAnnotations()
method in AnnotatedElementUtils.
Issue: SPR-13486
Prior to this commit, AnnotationUtils supported searching for
repeatable annotations even if the repeatable annotation was declared
on a custom stereotype annotation. However, there was no support for
merging of attributes in composed repeatable annotations. In other
words, it was not possible for a custom annotation to override
attributes in a repeatable annotation.
This commit addresses this by introducing
findMergedRepeatableAnnotations() methods in AnnotatedElementUtils.
These new methods provide full support for explicit annotation
attribute overrides configured via @AliasFor (as well as
convention-based overrides) with "find semantics".
Issue: SPR-13973
