Add Spotless Maven Plugin with Eclipse JDT formatter for AOSP code style

README.md

@@ -1,7 +1,71 @@
 # android-xml-formatter
 
-Formats xml files according to Android Studio's default formatting rules. By default, also re-orders the attributes to specify the `android:id`, `android:layout_width` and `android:layout_height` first. This can be turned off with a command line option.
+[![GitHub check runs](https://img.shields.io/github/check-runs/ByteHamster/android-xml-formatter/main)](https://github.com/ByteHamster/android-xml-formatter/actions/workflows/checks.yml?query=branch%3Amain)
+[![License: GPL v3](https://img.shields.io/github/license/ByteHamster/android-xml-formatter)](https://www.gnu.org/licenses/gpl-3.0)
+[![GitHub Release](https://img.shields.io/github/v/release/ByteHamster/android-xml-formatter)](https://github.com/ByteHamster/android-xml-formatter/releases)
 
-To view available command line options, execute `java -jar android-xml-formatter.jar --help`.
+Formats XML files according to Android Studio's default formatting rules. By default, also re-orders the attributes to specify the `android:id`, `android:layout_width` and `android:layout_height` first. This can be turned off with a command line option.
 
-Can be used as a style check on a CI server by executing and then printing the diff.
+## Requirements
+
+- Java 8 or higher
+- Maven 3.6 or higher
+
+## Building
+
+- `mvn clean package` to create an executable JAR file with all dependencies
+  at `target/android-xml-formatter-1.0-SNAPSHOT-jar-with-dependencies.jar`.
+- `mvn verify` runs all tests and code format checks.
+
+## Usage
+
+To view available command line options:
+
+```bash
+java -jar target/android-xml-formatter-1.0-SNAPSHOT-jar-with-dependencies.jar --help
+```
+
+| Option                      | Description                                                                |
+|-----------------------------|----------------------------------------------------------------------------|
+| `--indention <n>`           | Set indentation spaces (default: 4)                                        |
+| `--attribute-indention <n>` | Set attribute indentation spaces (default: 4)                              |
+| `--attribute-order <list>`  | Comma-separated attribute order (default: `id,layout_width,layout_height`) |
+| `--attribute-sort`          | Sort attributes alphabetically                                             |
+| `--namespace-order <list>`  | Comma-separated namespace order (default: `android`)                       |
+| `--namespace-sort`          | Sort namespaces alphabetically                                             |
+
+### Example
+
+Format an XML file:
+
+```bash
+java -jar target/android-xml-formatter-1.0-SNAPSHOT-jar-with-dependencies.jar path/to/layout.xml
+```
+
+Format multiple files:
+
+```bash
+java -jar target/android-xml-formatter-1.0-SNAPSHOT-jar-with-dependencies.jar file1.xml file2.xml file3.xml
+```
+
+## Contributing
+
+This project uses [Spotless Maven Plugin](https://github.com/diffplug/spotless/tree/main/plugin-maven)
+with Eclipse JDT formatter for Java code formatting, configured to match the
+[AOSP (Android Open Source Project) code style](https://source.android.com/docs/setup/contribute/code-style).
+
+To verify that all Java code follows the formatting rules, run `mvn spotless:check`.
+To automatically format all Java code, run `mvn spotless:apply`.
+
+## CI Integration
+
+This project can be used as a style check on a CI server by executing the formatter and then printing the diff:
+
+```bash
+java -jar android-xml-formatter.jar *.xml
+git diff --exit-code
+```
+
+## License
+
+See [LICENSE](LICENSE) file for details.

pom.xml

@@ -33,6 +33,32 @@
 
     <build>
         <plugins>
+            <plugin>
+                <groupId>com.diffplug.spotless</groupId>
+                <artifactId>spotless-maven-plugin</artifactId>
+                <version>2.43.0</version>
+                <configuration>
+                    <java>
+                        <!-- Eclipse JDT formatter with AOSP code style -->
+                        <eclipse>
+                            <file>${project.basedir}/settings/eclipse-aosp-style.xml</file>
+                        </eclipse>
+                        <!-- Import ordering matching AOSP style -->
+                        <importOrder>
+                            <order>android,androidx,com.android,dalvik,libcore,com,org,java,javax,</order>
+                        </importOrder>
+                        <removeUnusedImports/>
+                    </java>
+                </configuration>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>check</goal>
+                        </goals>
+                        <phase>verify</phase>
+                    </execution>
+                </executions>
+            </plugin>
             <plugin>
                 <artifactId>maven-assembly-plugin</artifactId>
                 <version>3.1.1</version>
@@ -59,4 +85,4 @@
             </plugin>
         </plugins>
     </build>
-</project>
+</project>