Use var for reference-typed variables

org.openrewrite.java.migrate.lang.var.UseVarForObject

Try to apply local variable type inference var to variables containing Objects where possible. This recipe will not touch variable declarations with generics or initializers containing ternary operators.

Recipe source

GitHub, Issue Tracker, Maven Central

• groupId: org.openrewrite.recipe

• artifactId: rewrite-migrate-java

• version: 2.12.0

Usage

This recipe has no required configuration options. It can be activated by adding a dependency on org.openrewrite.recipe:rewrite-migrate-java:2.12.0 in your build file or by running a shell command (in which case no build changes are needed):

Gradle

1. Add the following to your build.gradle file:

build.gradle

plugins {
    id("org.openrewrite.rewrite") version("6.12.0")
}

rewrite {
    activeRecipe("org.openrewrite.java.migrate.lang.var.UseVarForObject")
}

repositories {
    mavenCentral()
}

dependencies {
    rewrite("org.openrewrite.recipe:rewrite-migrate-java:2.12.0")
}

2. Run gradle rewriteRun to run the recipe.

Gradle init script

1. Create a file named init.gradle in the root of your project.

init.gradle

initscript {
    repositories {
        maven { url "https://plugins.gradle.org/m2" }
    }
    dependencies { classpath("org.openrewrite:plugin:6.12.0") }
}
rootProject {
    plugins.apply(org.openrewrite.gradle.RewritePlugin)
    dependencies {
        rewrite("org.openrewrite.recipe:rewrite-migrate-java:2.12.0")
    }
    rewrite {
        activeRecipe("org.openrewrite.java.migrate.lang.var.UseVarForObject")
    }
    afterEvaluate {
        if (repositories.isEmpty()) {
            repositories {
                mavenCentral()
            }
        }
    }
}

2. Run gradle --init-script init.gradle rewriteRun to run the recipe.

Maven POM

1. Add the following to your pom.xml file:

pom.xml

<project>
  <build>
    <plugins>
      <plugin>
        <groupId>org.openrewrite.maven</groupId>
        <artifactId>rewrite-maven-plugin</artifactId>
        <version>5.29.0</version>
        <configuration>
          <activeRecipes>
            <recipe>org.openrewrite.java.migrate.lang.var.UseVarForObject</recipe>
          </activeRecipes>
        </configuration>
        <dependencies>
          <dependency>
            <groupId>org.openrewrite.recipe</groupId>
            <artifactId>rewrite-migrate-java</artifactId>
            <version>2.12.0</version>
          </dependency>
        </dependencies>
      </plugin>
    </plugins>
  </build>
</project>

2. Run mvn rewrite:run to run the recipe.

Maven Command Line

shell

mvn -U org.openrewrite.maven:rewrite-maven-plugin:run -Drewrite.recipeArtifactCoordinates=org.openrewrite.recipe:rewrite-migrate-java:RELEASE -Drewrite.activeRecipes=org.openrewrite.java.migrate.lang.var.UseVarForObject

Moderne CLI

You will need to have configured the Moderne CLI on your machine before you can run the following command.

shell

mod run . --recipe UseVarForObject

See how this recipe works across multiple open-source repositories

The community edition of the Moderne platform enables you to easily run recipes across thousands of open-source repositories.

Please contact Moderne for more information about safely running the recipes on your own codebase in a private SaaS.

Contributors

Merlin Bögershausen, Knut Wannheden, Tim te Beek, Mike Solomon