Moderne licensed

Collapse `sorted().first/last()` and `reversed().first/last()` chains

Recipe IDorg.openrewrite.kotlin.performance.CollapseSortAndReverse$KtRecipeArtifactio.moderne.recipe:recipes-kotlin

Replaces O(n log n) sorts whose only purpose is to read one element with the equivalent O(n) min/max/minBy/maxBy, and elides unnecessary reversed() copies before first/last.

Composite recipeProprietary

Add to your build

Get a download tokenThis recipe is Moderne licensed, so the token must belong to a Moderne customer. It replaces YOUR_DOWNLOAD_TOKEN below.

~/.gradle/gradle.properties

codeGenomeUsername=you@example.com
codeGenomeToken=YOUR_DOWNLOAD_TOKEN

build.gradle.kts

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

rewrite {
    activeRecipe("org.openrewrite.kotlin.performance.CollapseSortAndReverse$KtRecipe")
}

repositories {
    mavenCentral()
    maven {
        url = uri("https://artifacts.codegenomeproject.org/maven")
        credentials {
            username = providers.gradleProperty("codeGenomeUsername").get()
            password = providers.gradleProperty("codeGenomeToken").get()
        }
    }
}

dependencies {
    rewrite("io.moderne.recipe:recipes-kotlin:0.5.0")
}

Then run

./gradlew rewriteRun

Usage

This recipe has no required configuration options. You’ll need the Moderne CLI configured before running the command below.

mod run . --recipe org.openrewrite.kotlin.performance.CollapseSortAndReverse$KtRecipe

If the recipe isn’t available locally, install it with:

mod config recipes jar install io.moderne.recipe:recipes-kotlin:RELEASE

Definition

This recipe runs the following recipes in order.

Use min() instead of sorted().first()org.openrewrite.kotlin.performance.UseMinForSortedFirst$KtRecipe
Use max() instead of sorted().last()org.openrewrite.kotlin.performance.UseMaxForSortedLast$KtRecipe
Use max() instead of sortedDescending().first()org.openrewrite.kotlin.performance.UseMaxForSortedDescendingFirst$KtRecipe
Use min() instead of sortedDescending().last()org.openrewrite.kotlin.performance.UseMinForSortedDescendingLast$KtRecipe
Use minBy { selector } instead of sortedBy { selector }.first()org.openrewrite.kotlin.performance.UseMinByForSortedByFirst$KtRecipe
Use maxBy { selector } instead of sortedBy { selector }.last()org.openrewrite.kotlin.performance.UseMaxByForSortedByLast$KtRecipe
Use last() instead of reversed().first()org.openrewrite.kotlin.performance.UseLastForReversedFirst$KtRecipe
Use first() instead of reversed().last()org.openrewrite.kotlin.performance.UseFirstForReversedLast$KtRecipe
Use sortedByDescending { f } instead of sortedBy { f }.reversed()org.openrewrite.kotlin.performance.UseSortedByDescendingForSortedByReversed$KtRecipe
Use sortedDescending() instead of sorted().reversed()org.openrewrite.kotlin.performance.UseSortedDescendingForSortedReversed$KtRecipe
Use mapTo(mutableListOf(), f) instead of map(f).toMutableList()org.openrewrite.kotlin.performance.UseMapToForMapToMutableList$KtRecipe
Use filterTo(mutableListOf(), p) instead of filter(p).toMutableList()org.openrewrite.kotlin.performance.UseFilterToForFilterToMutableList$KtRecipe
Use filterNotTo(mutableListOf(), p) instead of filterNot(p).toMutableList()org.openrewrite.kotlin.performance.UseFilterNotToForFilterNotToMutableList$KtRecipe
Use flatMapTo(mutableListOf(), f) instead of flatMap(f).toMutableList()org.openrewrite.kotlin.performance.UseFlatMapToForFlatMapToMutableList$KtRecipe

Data tables

Structured output this recipe can produce.

Source files that had resultsSource files that were modified by the recipe run.org.openrewrite.table.SourcesFileResults
Source files that had search resultsSearch results that were found during the recipe run.org.openrewrite.table.SearchResults
Source files that errored on a recipeThe details of all errors produced by a recipe run.org.openrewrite.table.SourcesFileErrors
Recipe performanceStatistics used in analyzing the performance of recipes.org.openrewrite.table.RecipeRunStats