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https://issues.apache.org/jira/browse/SLING-12359?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Stefan Seifert resolved SLING-12359.
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Resolution: Fixed
https://github.com/apache/sling-org-apache-sling-models-impl/commit/9d1c72501226d3dfdfb0644c5632f5e29be5370e
> Sling Models: Support constructor injection for Java Record classes
> -------------------------------------------------------------------
>
> Key: SLING-12359
> URL: https://issues.apache.org/jira/browse/SLING-12359
> Project: Sling
> Issue Type: Improvement
> Components: Sling Models
> Affects Versions: Models Implementation 1.6.4
> Reporter: Herman Ciechanowiec
> Assignee: Stefan Seifert
> Priority: Major
> Fix For: Models Implementation 1.6.6
>
>
> Java 14 introduced support for record classes, and Apache Sling 12 by default
> runs with Java 17, allowing the use of records.
> Although Apache Sling 12 supports record classes, the current latest version
> of Apache Sling Models Implementation does not fully support injection in
> relation to records. Specifically, for records, the Apache Sling Models
> Implementation *does* support constructor injection similarly to a usual
> class if there is an *explicit* constructor annotated with
> `javax.inject.Inject`:
> {code:java}
> @Model(
> adaptables = {Resource.class, SlingHttpServletRequest.class},
> defaultInjectionStrategy = DefaultInjectionStrategy.REQUIRED
> )
> public record StudentModel(String name, int age) {
> @Inject
> public StudentModel(
> @ValueMapValue(name = "name") @Default(values = "unknown")
> String name,
> @ValueMapValue(name = "age") @Default(intValues = 0)
> int age
> ) {
> this.name = name;
> this.age = age;
> }
> }
> {code}
> However, for records, Apache Sling Models Implementation *does not* support
> constructor injection if there is an *implicit* constructor. Such a
> constructor cannot be annotated with `javax.inject.Inject` and will not be
> picked up during injection. Therefore, such a Sling Model will not be
> instantiated at all:
> {code:java}
> @Model(
> adaptables = {Resource.class, SlingHttpServletRequest.class},
> defaultInjectionStrategy = DefaultInjectionStrategy.REQUIRED
> )
> public record StudentModel(
> @ValueMapValue(name = "name") @Default(values = "unknown")
> String name,
> @ValueMapValue(name = "age") @Default(intValues = 0)
> int age
> ) {}
> {code}
> The above issue should be addressed by introducing support for injection in
> records' implicit constructors.
> Note:
> 1. For records, only constructor injection is supported since records cannot
> have instance fields (code with such fields will not compile).
> 2. Apache Sling Models Implementation is currently based on Java 8 and may
> also be executed in a Java 8 environment. Therefore, the records check should
> be introduced via dynamic loading of the `java.lang.Record` class.
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