uselambdaforfunctionalinterface.md

Use lambda expressions instead of anonymous classes

org.openrewrite.staticanalysis.UseLambdaForFunctionalInterface

Instead of anonymous class declarations, use a lambda where possible. Using lambdas to replace anonymous classes can lead to more expressive and maintainable code, improve code readability, reduce code duplication, and achieve better performance in some cases.

Tags

• RSPEC-1604

Source

GitHub, Issue Tracker, Maven Central

• groupId: org.openrewrite.recipe
• artifactId: rewrite-static-analysis
• version: 1.0.1

Example

{% tabs %} {% tab title="Test.java" %}

Before

{% code title="Test.java" %}

import java.util.function.Function;
class Test {
    Function<Integer, Integer> f = new Function<Integer, Integer>() {
        @Override
        public Integer apply(Integer n) {
            return n + 1;
        }
    };
}

{% endcode %}

After

{% code title="Test.java" %}

import java.util.function.Function;
class Test {
    Function<Integer, Integer> f = n -> n + 1;
}

{% endcode %}

{% endtab %} {% tab title="Diff" %} {% code %}

--- Test.java
+++ Test.java
@@ -3,6 +3,1 @@
import java.util.function.Function;
class Test {
-   Function<Integer, Integer> f = new Function<Integer, Integer>() {
-       @Override
-       public Integer apply(Integer n) {
-           return n + 1;
-       }
-   };
+   Function<Integer, Integer> f = n -> n + 1;
}

{% endcode %} {% endtab %} {% endtabs %}

Usage

This recipe has no required configuration options. It can be activated by adding a dependency on org.openrewrite.recipe:rewrite-static-analysis:1.0.1 in your build file or by running a shell command (in which case no build changes are needed): {% tabs %} {% tab title="Gradle" %} {% code title="build.gradle" %}

plugins {
    id("org.openrewrite.rewrite") version("6.1.4")
}

rewrite {
    activeRecipe("org.openrewrite.staticanalysis.UseLambdaForFunctionalInterface")
}

repositories {
    mavenCentral()
}

dependencies {
    rewrite("org.openrewrite.recipe:rewrite-static-analysis:1.0.1")
}

{% endcode %} {% endtab %} {% tab title="Maven POM" %} {% code title="pom.xml" %}

<project>
  <build>
    <plugins>
      <plugin>
        <groupId>org.openrewrite.maven</groupId>
        <artifactId>rewrite-maven-plugin</artifactId>
        <version>5.2.4</version>
        <configuration>
          <activeRecipes>
            <recipe>org.openrewrite.staticanalysis.UseLambdaForFunctionalInterface</recipe>
          </activeRecipes>
        </configuration>
        <dependencies>
          <dependency>
            <groupId>org.openrewrite.recipe</groupId>
            <artifactId>rewrite-static-analysis</artifactId>
            <version>1.0.1</version>
          </dependency>
        </dependencies>
      </plugin>
    </plugins>
  </build>
</project>

{% endcode %} {% endtab %}

{% tab title="Maven Command Line" %} {% code title="shell" %} You will need to have Maven installed on your machine before you can run the following command.

mvn -U org.openrewrite.maven:rewrite-maven-plugin:run \
  -Drewrite.recipeArtifactCoordinates=org.openrewrite.recipe:rewrite-static-analysis:RELEASE \
  -Drewrite.activeRecipes=org.openrewrite.staticanalysis.UseLambdaForFunctionalInterface

{% endcode %} {% endtab %} {% endtabs %}

Contributors

• Jonathan Schneider
• Knut Wannheden
• Tracey Yoshima
• Kun Li
• Tyler Van Gorder
• Nick McKinney
• Sam Snyder

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