Fix shaded formatter prefs

Update the shaded jar so that the key values in `formatter.prefs` are
also processed.

Prior to this commit the keys all started with `org.eclipse` and were
unfortunately not picked up due to the fact that the shade plugin
changed the value of the `JavaCore.PLUGIN_ID` constant in the bytecode.

Closes gh-161

spring-javaformat/pom.xml

@@ -36,6 +36,7 @@
 		<module>spring-javaformat-formatter-eclipse-runtime</module>
 		<module>spring-javaformat-formatter-eclipse</module>
 		<module>spring-javaformat-formatter</module>
+		<module>spring-javaformat-formatter-shader</module>
 		<module>spring-javaformat-formatter-shaded</module>
 	</modules>
 </project>

spring-javaformat/spring-javaformat-formatter-shaded/pom.xml

@@ -48,6 +48,13 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-shade-plugin</artifactId>
+				<dependencies>
+					<dependency>
+						<groupId>${project.groupId}</groupId>
+						<artifactId>spring-javaformat-formatter-shader</artifactId>
+						<version>${project.version}</version>
+					</dependency>
+				</dependencies>
 				<configuration>
 					<createSourcesJar>true</createSourcesJar>
 					<promoteTransitiveDependencies>true</promoteTransitiveDependencies>
@@ -71,6 +78,9 @@
 							<shadedPattern>io.spring.javaformat.org.osgi</shadedPattern>
 						</relocation>
 					</relocations>
+					<transformers>
+						<transformer implementation="io.spring.javaformat.formatter.shader.PrefsResourceTransformer" />
+					</transformers>
 				</configuration>
 				<executions>
 					<execution>
@@ -84,7 +94,6 @@
 		</plugins>
 	</build>
 	<dependencies>
-		<!-- Provided -->
 		<dependency>
 			<groupId>io.spring.javaformat</groupId>
 			<artifactId>spring-javaformat-formatter</artifactId>

spring-javaformat/spring-javaformat-formatter-shader/pom.xml

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>io.spring.javaformat</groupId>
+		<artifactId>spring-javaformat</artifactId>
+		<version>0.0.18-SNAPSHOT</version>
+	</parent>
+	<artifactId>spring-javaformat-formatter-shader</artifactId>
+	<name>Spring JavaFormat Formatter Shaded</name>
+	<properties>
+		<main.basedir>${basedir}/../..</main.basedir>
+	</properties>
+	<dependencies>
+		<dependency>
+			<groupId>org.apache.maven.plugins</groupId>
+			<artifactId>maven-shade-plugin</artifactId>
+			<version>3.1.0</version>
+			<type>maven-plugin</type>
+		</dependency>
+	</dependencies>
+</project>

spring-javaformat/spring-javaformat-formatter-shader/src/main/java/io/spring/javaformat/formatter/shader/PrefsResourceTransformer.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright 2017-2020 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 io.spring.javaformat.formatter.shader;
+
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStreamWriter;
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.jar.JarEntry;
+import java.util.jar.JarOutputStream;
+
+import org.apache.maven.plugins.shade.relocation.Relocator;
+import org.apache.maven.plugins.shade.resource.ResourceTransformer;
+
+/**
+ * {@link ResourceTransformer} to fix formatter preference files.
+ *
+ * @author Phillip Webb
+ */
+public class PrefsResourceTransformer implements ResourceTransformer {
+
+	private final Map<String, List<String>> transformedResources = new LinkedHashMap<>();
+
+	@Override
+	public boolean canTransformResource(String resource) {
+		return resource.endsWith("formatter.prefs");
+	}
+
+	@Override
+	public void processResource(String resource, InputStream is, List<Relocator> relocators) throws IOException {
+		List<String> trandformedLines = new ArrayList<>();
+		BufferedReader reader = new BufferedReader(new InputStreamReader(is));
+		String line = reader.readLine();
+		while (line != null) {
+			trandformedLines.add(transformLine(line, relocators));
+			line = reader.readLine();
+		}
+		this.transformedResources.put(resource, trandformedLines);
+	}
+
+	private String transformLine(String line, List<Relocator> relocators) {
+		int splitIndex = line.lastIndexOf('=');
+		if (splitIndex == -1) {
+			return line;
+		}
+		String key = line.substring(0, splitIndex);
+		String value = line.substring(splitIndex + 1);
+		return relocateKey(key, relocators) + "=" + value;
+	}
+
+	private String relocateKey(String key, List<Relocator> relocators) {
+		for (Relocator relocator : relocators) {
+			if (relocator.canRelocateClass(key)) {
+				return relocator.relocateClass(key);
+			}
+		}
+		return key;
+	}
+
+	@Override
+	public boolean hasTransformedResource() {
+		return true;
+	}
+
+	@Override
+	public void modifyOutputStream(JarOutputStream os) throws IOException {
+		for (Map.Entry<String, List<String>> entry : this.transformedResources.entrySet()) {
+			write(os, entry.getKey(), entry.getValue());
+		}
+	}
+
+	private void write(JarOutputStream os, String resource, List<String> lines) throws IOException {
+		os.putNextEntry(new JarEntry(resource));
+		BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os));
+		for (String line : lines) {
+			writer.write(line);
+			writer.write("\n");
+		}
+		writer.flush();
+	}
+
+}