Update project layout for Groovy-based projects

A groovy-based project on Maven provides a better developer experience
if the sources are located in src/main/java and src/test/java.

This commit updates the generator to use this new location while keeping
the existing src/main/groovy project for Gradle builds.

Fixes gh-71

CHANGELOG.adoc

@@ -7,6 +7,7 @@ order.
 
 === Release 1.0.0 (In progress)
 
+* https://github.com/spring-io/initializr/issues/71[#71]: update project layout for Groovy-based projects.
 * https://github.com/spring-io/initializr/issues/69[#69]: improve the structure of templated urls.
 * https://github.com/spring-io/initializr/issues/70[#70]: explicit support for HTTPie (similar to curl).
 * https://github.com/spring-io/initializr/issues/67[#67]: explicit support for curl by returning a text

initializr/src/main/groovy/io/spring/initializr/ProjectGenerator.groovy

@@ -81,7 +81,8 @@ class ProjectGenerator {
 
 		def dir = initializerProjectDir(rootDir, request)
 
-		if ('gradle'.equals(request.build)) {
+		boolean gradleBuild = 'gradle'.equals(request.build)
+		if (gradleBuild) {
 			def gradle = new String(doGenerateGradleBuild(model))
 			new File(dir, 'build.gradle').write(gradle)
 		} else {
@@ -92,7 +93,8 @@ class ProjectGenerator {
 		def applicationName = request.applicationName
 		def language = request.language
 
-		def src = new File(new File(dir, "src/main/$language"), request.packageName.replace('.', '/'))
+		String codeLocation = ((language.equals("groovy") && gradleBuild) ? 'groovy': 'java')
+		def src = new File(new File(dir, "src/main/$codeLocation"), request.packageName.replace('.', '/'))
 		src.mkdirs()
 		write(new File(src, "${applicationName}.${language}"), "Application.$language", model)
 
@@ -101,7 +103,7 @@ class ProjectGenerator {
 			write(new File(src, fileName), fileName, model)
 		}
 
-		def test = new File(new File(dir, "src/test/$language"), request.packageName.replace('.', '/'))
+		def test = new File(new File(dir, "src/test/$codeLocation"), request.packageName.replace('.', '/'))
 		test.mkdirs()
 		if (request.hasWebFacet()) {
 			model.testAnnotations = '@WebAppConfiguration\n'

initializr/src/test/groovy/io/spring/initializr/ProjectGeneratorTests.groovy

@@ -184,7 +184,7 @@ class ProjectGeneratorTests {
 		request.bootVersion = '1.1.9.RELEASE'
 		request.name = 'MyDemo'
 		request.packageName = 'foo'
-		generateProject(request).sourceCodeAssert('src/main/groovy/foo/MyDemoApplication.groovy')
+		generateProject(request).sourceCodeAssert('src/main/java/foo/MyDemoApplication.groovy')
 				.hasImports(EnableAutoConfiguration.class.name, ComponentScan.class.name, Configuration.class.name)
 				.doesNotHaveImports(SpringBootApplication.class.name)
 				.contains('@EnableAutoConfiguration', '@Configuration', '@ComponentScan')
@@ -198,7 +198,7 @@ class ProjectGeneratorTests {
 		request.bootVersion = '1.2.0.RC1'
 		request.name = 'MyDemo'
 		request.packageName = 'foo'
-		generateProject(request).sourceCodeAssert('src/main/groovy/foo/MyDemoApplication.groovy')
+		generateProject(request).sourceCodeAssert('src/main/java/foo/MyDemoApplication.groovy')
 				.hasImports(SpringBootApplication.class.name)
 				.doesNotHaveImports(EnableAutoConfiguration.class.name, ComponentScan.class.name, Configuration.class.name)
 				.contains('@SpringBootApplication')
@@ -214,6 +214,22 @@ class ProjectGeneratorTests {
 				.isMavenProject()
 	}
 
+	@Test
+	void groovyWithMavenUsesJavaDir() {
+		def request = createProjectRequest('web')
+		request.type  = 'maven-project'
+		request.language = 'groovy'
+		generateProject(request).isMavenProject().isGroovyProject()
+	}
+
+	@Test
+	void groovyWithGradleUsesGroovyDir() {
+		def request = createProjectRequest('web')
+		request.type  = 'gradle-project'
+		request.language = 'groovy'
+		generateProject(request).isGradleProject().isGroovyProject()
+	}
+
 	PomAssert generateMavenPom(ProjectRequest request) {
 		def content = new String(projectGenerator.generateMavenPom(request))
 		new PomAssert(content).validateProjectRequest(request)

initializr/src/test/groovy/io/spring/initializr/test/ProjectAssert.groovy

@@ -32,6 +32,7 @@ class ProjectAssert {
 	private static final DEFAULT_APPLICATION_NAME = generateDefaultApplicationName()
 
 	final File dir
+	Boolean mavenProject
 
 	/**
 	 * Create a new instance with the directory holding the generated project.
@@ -80,10 +81,14 @@ class ProjectAssert {
 
 	ProjectAssert isMavenProject() {
 		hasFile('pom.xml').hasNoFile('build.gradle')
+		mavenProject = true
+		this
 	}
 
 	ProjectAssert isGradleProject() {
 		hasFile('build.gradle').hasNoFile('pom.xml')
+		mavenProject = false
+		this
 	}
 
 	ProjectAssert isJavaProject(String expectedApplicationName) {
@@ -97,8 +102,9 @@ class ProjectAssert {
 	}
 
 	ProjectAssert isGroovyProject(String expectedApplicationName) {
-		hasFile("src/main/groovy/demo/${expectedApplicationName}.groovy",
+		String codeLocation = (mavenProject ? 'java' : 'groovy')
-				"src/test/groovy/demo/${expectedApplicationName}Tests.groovy",
+		hasFile("src/main/$codeLocation/demo/${expectedApplicationName}.groovy",
+				"src/test/$codeLocation/demo/${expectedApplicationName}Tests.groovy",
 				'src/main/resources/application.properties')
 	}