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Properly use declaration-site type variance

org.openrewrite.java.cleanup.DeclarationSiteTypeVariance Currently, Java requires use-site type variance, so if someone has Function<IN, OUT> method parameter, it should rather be Function<? super IN, ? extends OUT>. Unfortunately, it is not easy to notice that ? super and ? extends is missing, so this recipe adds it where that would improve the situation.

Source

  • groupId: org.openrewrite
  • artifactId: rewrite-java
  • version: 7.35.0

Options

Type
Name
Description
List
variantTypes
A list of well-known classes that have in/out type variance.
List
excludedBounds
Optional. A list of bounds that should not receive explicit variance. Globs supported.
Boolean
excludeFinalClasses
Optional. If true, do not add ? extends variance to final classes. ? super variance will be added regardless of finality.

Usage

This recipe has required configuration parameters. Recipes with required configuration parameters cannot be activated directly. To activate this recipe you must create a new recipe which fills in the required parameters. In your rewrite.yml create a new recipe with a unique name. For example: com.yourorg.DeclarationSiteTypeVarianceExample. Here's how you can define and customize such a recipe within your rewrite.yml:
rewrite.yml
---
type: specs.openrewrite.org/v1beta/recipe
name: com.yourorg.DeclarationSiteTypeVarianceExample
displayName: Properly use declaration-site type variance example
recipeList:
- org.openrewrite.java.cleanup.DeclarationSiteTypeVariance:
variantTypes: java.util.function.Function<IN, OUT>
excludedBounds: java.lang.*
excludeFinalClasses: null
Now that com.yourorg.DeclarationSiteTypeVarianceExample has been defined activate it in your build file:
Gradle
Maven
build.gradle
plugins {
id("org.openrewrite.rewrite") version("5.34.0")
}
rewrite {
activeRecipe("com.yourorg.DeclarationSiteTypeVarianceExample")
}
repositories {
mavenCentral()
}
pom.xml
<project>
<build>
<plugins>
<plugin>
<groupId>org.openrewrite.maven</groupId>
<artifactId>rewrite-maven-plugin</artifactId>
<version>4.39.0</version>
<configuration>
<activeRecipes>
<recipe>com.yourorg.DeclarationSiteTypeVarianceExample</recipe>
</activeRecipes>
</configuration>
</plugin>
</plugins>
</build>
</project>
Recipes can also be activated directly from the command line by adding the argument -Drewrite.activeRecipes=com.yourorg.DeclarationSiteTypeVarianceExample

See how this recipe works across multiple open-source repositories

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