gradle scripts: make javaCC code reusable by using a gradle plugin

Author: svene

buildSrc/src/main/groovy/JavaCCPlugin.groovy

@@ -32,7 +32,7 @@ dependencies {
 // Apply a specific Java toolchain to ease working on different environments.
 java {
     toolchain {
-        languageVersion = JavaLanguageVersion.of(21)
+        languageVersion = JavaLanguageVersion.of(23)
     }
 }
 

buildSrc/src/main/groovy/JavaCCTask.groovy

@@ -27,7 +27,7 @@ dependencies {
 // Apply a specific Java toolchain to ease working on different environments.
 java {
     toolchain {
-        languageVersion = JavaLanguageVersion.of(21)
+        languageVersion = JavaLanguageVersion.of(23)
     }
 }
 

buildSrc/src/main/groovy/buildlogic.groovy-common-conventions.gradle

@@ -0,0 +1,52 @@
+package org.xcommand
+
+import org.gradle.api.*
+import org.gradle.api.provider.Property
+import org.gradle.api.tasks.Copy
+
+class JavaCCPluginExtension {
+	final Property<File> inputFile
+	final Property<File> genDir
+
+	JavaCCPluginExtension(Project project) {
+		inputFile = project.objects.property(File)
+		genDir = project.objects.property(File)
+	}
+}
+
+class JavaCCPlugin implements Plugin<Project>  {
+	void apply(Project project) {
+		def ext = project.extensions.create("javacc", JavaCCPluginExtension, project)
+		def versionJavacc = project.findProperty('VERSION_JAVACC') ?: 'UNKNOWN'
+
+		project.tasks.register('copyToLib', Copy) {
+			into("${project.buildDir}/_artifacts")
+			from project.configurations.compileClasspath
+			from project.configurations.default.allArtifacts*.file
+			from project.configurations.compileClasspath.allArtifacts*.file
+		}
+
+		project.tasks.register('renameJCC', Copy) {
+			dependsOn project.tasks.named('copyToLib')
+			from("${project.buildDir}/_artifacts/javacc-${versionJavacc}.jar")
+			into("${project.buildDir}/_artifacts")
+			rename("javacc-${versionJavacc}.jar", "javacc.jar")
+		}
+
+		// jcc task
+		project.tasks.register('jcc', JavaCCTask) { JavaCCTask t ->
+			dependsOn(project.tasks.named('renameJCC'))
+
+			// must be provided by the caller; fail if missing
+			t.inputFile.set(ext.inputFile)
+			t.genDir.set(ext.genDir)
+
+			// Add generated directory to main source set lazily
+			project.sourceSets.main.java.srcDirs += t.genDir
+		}
+
+	}
+
+}
+
+

buildSrc/src/main/groovy/buildlogic.java-common-conventions.gradle

@@ -0,0 +1,25 @@
+package org.xcommand
+
+import org.gradle.api.*
+import org.gradle.api.provider.Property
+import org.gradle.api.tasks.*
+
+class JavaCCTask extends DefaultTask {
+	@InputFile
+	final Property<File> inputFile = project.objects.property(File)
+
+	@OutputDirectory
+	final Property<File> genDir = project.objects.property(File)
+
+	@TaskAction
+	void generate() {
+		println "generate jcc source"
+		File input = inputFile.get()
+		File output = genDir.get()
+
+		ant.mkdir(dir: output)
+		ant.javacc(target: input, outputdirectory: output, javacchome: 'build/_artifacts')
+	}
+
+}
+

buildSrc/src/main/groovy/org/xcommand/JavaCCPlugin.groovy

@@ -0,0 +1 @@
+implementation-class=org.xcommand.JavaCCPlugin

buildSrc/src/main/groovy/org/xcommand/JavaCCTask.groovy

@@ -1,26 +1,13 @@
 plugins {
 	id 'buildlogic.groovy-library-conventions'
 	alias(libs.plugins.versions)
+	id "org.xcommand.javacc"
 }
 
-task ('copyToLib', type: Copy) {
-	into('build/_artifacts')
-	from configurations.compileClasspath
-	from configurations.default.allArtifacts*.file
-	from configurations.compileClasspath.allArtifacts*.file
+javacc {
+	inputFile = file("src/main/javacc/templateparser.jj")
+	genDir    = file("build/src/java/org/collage/jcc")
 }
-
-task renameJCC(type: Copy, dependsOn: 'copyToLib') {
-	from("build/_artifacts/javacc-${VERSION_JAVACC}.jar")
-	into('build/_artifacts')
-	rename("javacc-${VERSION_JAVACC}.jar", 'javacc.jar')
-}
-
-task jcc (dependsOn: 'renameJCC', type: JavaCCTask) {
-	inputFile = file('src/main/javacc/templateparser.jj')
-	genDir = file('build/src/java/org/collage/jcc')
-}
-
 compileJava.dependsOn(jcc)
 
 dependencies {

buildSrc/src/main/resources/META-INF/gradle-plugins/org.xcommand.javacc.properties

@@ -1,24 +1,13 @@
 plugins {
 	id 'buildlogic.java-library-conventions'
 	alias(libs.plugins.versions)
+	id "org.xcommand.javacc"
 }
 
-task ('copyToLib', type: Copy) {
-	into('build/_artifacts')
-	from configurations.compileClasspath
-	from configurations.default.allArtifacts*.file
-	from configurations.compileClasspath.allArtifacts*.file
+javacc {
+	inputFile = file("src/main/javacc/jst.jj")
+	genDir    = file("build/src/java/org/xcommand/template/jst/parser")
 }
-task renameJCC(type: Copy, dependsOn: 'copyToLib') {
-	from("build/_artifacts/javacc-${VERSION_JAVACC}.jar")
-	into('build/_artifacts')
-	rename("javacc-${VERSION_JAVACC}.jar", 'javacc.jar')
-}
-task jcc (dependsOn: 'renameJCC', type: JavaCCTask) {
-	inputFile = 'src/main/javacc/jst.jj'
-	genDir = 'build/src/java/org/xcommand/template/jst/parser'
-}
-
 compileJava.dependsOn(jcc)
 
 sourceSets {