Open source

Use lambda expressions instead of anonymous classes

Recipe IDorg.openrewrite.staticanalysis.UseLambdaForFunctionalInterface

Artifactorg.openrewrite.recipe:rewrite-static-analysis

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.

Single recipeOpenRewriteRSPEC-S1604Moderne Source Available License

Try in PlatformTry this recipe in the Moderne platform. Not a user yet? You’ll get a no-setup demo environment, with nothing to install or configure.

Examples

java

java

Before

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

After

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

Diff

@@ -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;
}

Usage

Run this recipe

This recipe has no required configuration options. Users of Moderne can run it via the 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 UseLambdaForFunctionalInterface

If the recipe is not available locally, then you can install it using:

RELEASE resolves to the newest release and LATEST to the newest build of any kind, including snapshots. Either one lets mod config recipes upgrade pull in later versions without editing this command; a pinned version stays where you put it.

RELEASE

mod config recipes jar install org.openrewrite.recipe:rewrite-static-analysis:RELEASE

LATEST

mod config recipes jar install org.openrewrite.recipe:rewrite-static-analysis:LATEST

Pinned version

mod config recipes jar install org.openrewrite.recipe:rewrite-static-analysis:2.42.0

Data tables

Anonymous functional interface implementations

org.openrewrite.staticanalysis.table.AnonymousFunctionalInterfaceImplementations

Every anonymous class that implements a functional interface, whether or not it could be rewritten to a lambda, plus the sites that could not be decided either way because the supertype carries incomplete type attribution. Sites that were not rewritten carry the reason why.

Column	Description
Source path	The path to the source file containing the anonymous class.
Class	The fully qualified name of the class containing the anonymous class.
Functional interface	The fully qualified name of the functional interface being implemented, or the supertype as written at the site when it did not resolve.
Method	The name of the interface's single abstract method, or empty when type attribution was too incomplete to identify one.
Convertible to lambda	Whether the anonymous class could be rewritten to a lambda automatically.
Reason	Why the anonymous class was not rewritten, or empty when it was. Reasons naming missing type information mark sites the recipe is blind to rather than sites that are genuinely unconvertible, which usually means the LST was built without the dependencies those types come from.

Source files that had results

org.openrewrite.table.SourcesFileResults

Source files that were modified by the recipe run.

Column	Description
Source path before the run	The source path of the file before the run. null when a source file was created during the run.
Source path after the run	A 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 changes	In 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 changes	The specific recipe that made a change.
Estimated time saving	An estimated effort that a developer to fix manually instead of using this recipe, in unit of seconds.
Cycle	The recipe cycle in which the change was made.

Source files that had search results

org.openrewrite.table.SearchResults

Search results that were found during the recipe run.

Column	Description
Source path of search result before the run	The source path of the file with the search result markers present.
Source path of search result after run the run	A recipe may modify the source path. This is the path after the run. null when a source file was deleted during the run.
Result	The trimmed printed tree of the LST element that the marker is attached to.
Description	The content of the description of the marker.
Recipe that added the search marker	The specific recipe that added the Search marker.

Source files that errored on a recipe

org.openrewrite.table.SourcesFileErrors

The details of all errors produced by a recipe run.

Column	Description
Source path	The file that failed to parse.
Recipe that made changes	The specific recipe that made a change.
Stack trace	The stack trace of the failure.

Recipe performance

org.openrewrite.table.RecipeRunStats

Statistics used in analyzing the performance of recipes.

Column	Description
The recipe	The recipe whose stats are being measured both individually and cumulatively.
Source file count	The number of source files the recipe ran over.
Source file changed count	The number of source files which were changed in the recipe run. Includes files created, deleted, and edited.
Cumulative scanning time (ns)	The total time spent across the scanning phase of this recipe.
Max scanning time (ns)	The max time scanning any one source file.
Cumulative edit time (ns)	The total time spent across the editing phase of this recipe.
Max edit time (ns)	The max time editing any one source file.