Add Maven support

Author: mernst

README.md

@@ -61,7 +61,7 @@ lib('java.ImportOrderStep')                      +'{{yes}}       | {{yes}}
 lib('java.PalantirJavaFormatStep')               +'{{yes}}       | {{yes}}      | {{no}}       | {{no}}  |',
 lib('java.RemoveUnusedImportsStep')              +'{{yes}}       | {{yes}}      | {{yes}}      | {{no}}  |',
 extra('java.EclipseJdtFormatterStep')            +'{{yes}}       | {{yes}}      | {{yes}}      | {{no}}  |',
-lib('java.TypeAnnotationsStep')                  +'{{yes}}       | {{no}}       | {{no}}       | {{no}}  |',
+lib('java.TypeAnnotationsStep')                  +'{{yes}}       | {{yes}}      | {{no}}       | {{no}}  |',
 lib('json.gson.GsonStep')                        +'{{yes}}       | {{no}}       | {{no}}       | {{no}}  |',
 lib('json.JsonSimpleStep')                       +'{{yes}}       | {{no}}       | {{no}}       | {{no}}  |',
 lib('kotlin.KtLintStep')                         +'{{yes}}       | {{yes}}      | {{yes}}      | {{no}}  |',

plugin-maven/CHANGES.md

@@ -3,6 +3,8 @@
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `1.27.0`).
 
 ## [Unreleased]
+### Added
+* `typeAnnotations` step to correct formatting of type annotations.  It puts type annotations on the same line as the type that they qualify.  Run it after a Java formattng step, such as `googleJavaFormat`. ([#1275](https://github.com/diffplug/spotless/pull/1275))
 
 ## [2.25.0] - 2022-08-23
 ### Added

plugin-maven/README.md

@@ -24,7 +24,7 @@ output = [
 output = prefixDelimiterReplace(input, 'https://{{org}}.github.io/{{name}}/javadoc/spotless-plugin-maven/', '/', versionLast)
 -->
 
-Spotless is a general-purpose formatting plugin.  It is completely à la carte, but also includes powerful "batteries-included" if you opt-in. Plugin requires a version of Maven higher or equal to 3.1.0.
+Spotless is a general-purpose formatting plugin used by [4,000 projects on GitHub (August 2020)](https://github.com/search?l=gradle&q=spotless&type=Code).  It is completely à la carte, but also includes powerful "batteries-included" if you opt-in. Plugin requires a version of Maven higher or equal to 3.1.0.
 
 To people who use your build, it looks like this:
 
@@ -47,7 +47,7 @@ user@machine repo % mvn spotless:check
   - [Requirements](#requirements)
   - [Binding to maven phase](#binding-to-maven-phase)
 - **Languages**
-  - [Java](#java) ([google-java-format](#google-java-format), [eclipse jdt](#eclipse-jdt), [prettier](#prettier), [palantir-java-format](#palantir-java-format))
+  - [Java](#java) ([google-java-format](#google-java-format), [eclipse jdt](#eclipse-jdt), [prettier](#prettier), [palantir-java-format](#palantir-java-format), [type annotations](#type-annotations))
   - [Groovy](#groovy) ([eclipse groovy](#eclipse-groovy))
   - [Kotlin](#kotlin) ([ktfmt](#ktfmt), [ktlint](#ktlint), [diktat](#diktat), [prettier](#prettier))
   - [Scala](#scala) ([scalafmt](#scalafmt))
@@ -191,6 +191,8 @@ any other maven phase (i.e. compile) then it can be configured as below;
     <eclipse />          <!-- has its own section below -->
     <prettier />         <!-- has its own section below -->
 
+    <typeAnnotations />  <!-- fixes formatting of type annotations, see below -->
+
     <licenseHeader>
       <content>/* (C)$YEAR */</content>  <!-- or <file>${project.basedir}/license-header</file> -->
     </licenseHeader>
@@ -255,6 +257,33 @@ This is a workaround to a [pending issue](https://github.com/diffplug/spotless/i
 </eclipse>
 ```
 
+### Type annotations
+
+Type annotations should be on the same line as the type that they qualify.
+
+```java
+  @Override
+  @Deprecated
+  @Nullable @Interned String s;
+```
+
+However, some tools format them incorrectly, like this:
+
+```java
+  @Override
+  @Deprecated
+  @Nullable
+  @Interned
+  String s;
+```
+
+To fix the incorrect formatting, add the `typeAnnotations()` rule after a Java formatter.  For example:
+
+```XML
+<googleJavaFormat />
+<typeAnnotations />
+```
+
 ## Groovy
 
 [code](https://github.com/diffplug/spotless/blob/main/plugin-maven/src/main/java/com/diffplug/spotless/maven/groovy/Groovy.java). [available steps](https://github.com/diffplug/spotless/tree/main/plugin-maven/src/main/java/com/diffplug/spotless/maven/groovy).

plugin-maven/src/main/java/com/diffplug/spotless/maven/java/Java.java

@@ -61,4 +61,8 @@ public void addPalantirJavaFormat(PalantirJavaFormat palantirJavaFormat) {
 	public void addRemoveUnusedImports(RemoveUnusedImports removeUnusedImports) {
 		addStepFactory(removeUnusedImports);
 	}
+
+	public void addTypeAnnotations(TypeAnnotations typeAnnotations) {
+		addStepFactory(typeAnnotations);
+	}
 }

plugin-maven/src/main/java/com/diffplug/spotless/maven/java/TypeAnnotations.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2022 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.spotless.maven.java;
+
+import com.diffplug.spotless.FormatterStep;
+import com.diffplug.spotless.java.TypeAnnotationsStep;
+import com.diffplug.spotless.maven.FormatterStepConfig;
+import com.diffplug.spotless.maven.FormatterStepFactory;
+
+public class TypeAnnotations implements FormatterStepFactory {
+
+	@Override
+	public FormatterStep newFormatterStep(FormatterStepConfig config) {
+		return TypeAnnotationsStep.create();
+	}
+}

plugin-maven/src/test/java/com/diffplug/spotless/maven/java/TypeAnnotationsStepTest.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2022 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.spotless.maven.java;
+
+import org.junit.jupiter.api.Test;
+
+import com.diffplug.spotless.maven.MavenIntegrationHarness;
+
+class TypeAnnotationsStepTest extends MavenIntegrationHarness {
+
+	@Test
+	void testRemoveUnusedInports() throws Exception {
+		writePomWithJavaSteps("<typeAnnotations/>");
+
+		String path = "src/main/java/test.java";
+		setFile(path).toResource("java/typeannotations/TypeAnnotationsTestInput.test");
+		mavenRunner().withArguments("spotless:apply").runNoError();
+		assertFile(path).sameAsResource("java/typeannotations/TypeAnnotationsTestOutput.test");
+	}
+}