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Annotate null-checked method parameters with @Nullable

org.openrewrite.staticanalysis.AnnotateNullableParameters

Add @Nullable to parameters of public methods that are explicitly checked for null. By default org.jspecify.annotations.Nullable is used, but through the nullableAnnotationClass option a custom annotation can be provided. When providing a custom nullableAnnotationClass that annotation should be meta annotated with @Target(TYPE_USE). This recipe scans for methods that do not already have parameters annotated with @Nullable annotation and checks their usages for potential null checks.

Recipe source

GitHub, Issue Tracker, Maven Central

This recipe is available under the Moderne Source Available License.

Options

TypeNameDescriptionExample
StringnullableAnnotationClassOptional. The fully qualified name of the @Nullable annotation. The annotation should be meta annotated with @Target(TYPE_USE). Defaults to org.jspecify.annotations.Nullableorg.jspecify.annotations.Nullable

Example

Parameters
ParameterValue
nullableAnnotationClassnull
Before
public class PersonBuilder {
private String name = "Unknown";

public PersonBuilder setName(String name) {
if (name == null) {
return this;
}
this.name = name.substring(0, 1).toUpperCase() + name.substring(1);
return this;
}
}
After
import org.jspecify.annotations.Nullable;

public class PersonBuilder {
private String name = "Unknown";

public PersonBuilder setName(@Nullable String name) {
if (name == null) {
return this;
}
this.name = name.substring(0, 1).toUpperCase() + name.substring(1);
return this;
}
}

Usage

This recipe has no required configuration options. It can be activated by adding a dependency on org.openrewrite.recipe:rewrite-static-analysis in your build file or by running a shell command (in which case no build changes are needed):

  1. Add the following to your build.gradle file:
build.gradle
plugins {
id("org.openrewrite.rewrite") version("latest.release")
}

rewrite {
activeRecipe("org.openrewrite.staticanalysis.AnnotateNullableParameters")
setExportDatatables(true)
}

repositories {
mavenCentral()
}

dependencies {
rewrite("org.openrewrite.recipe:rewrite-static-analysis:2.11.0")
}
  1. Run gradle rewriteRun to run the recipe.

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Data Tables

Source files that had results

org.openrewrite.table.SourcesFileResults

Source files that were modified by the recipe run.

Column NameDescription
Source path before the runThe source path of the file before the run. null when a source file was created during the run.
Source path after the runA recipe may modify the source path. This is the path after the run. null when a source file was deleted during the run.
Parent of the recipe that made changesIn a hierarchical recipe, the parent of the recipe that made a change. Empty if this is the root of a hierarchy or if the recipe is not hierarchical at all.
Recipe that made changesThe specific recipe that made a change.
Estimated time savingAn estimated effort that a developer to fix manually instead of using this recipe, in unit of seconds.
CycleThe recipe cycle in which the change was made.

Contributors

Stefano Dalla Palma, Tim te Beek