Allow Java source formatting mvn formatter:format (#4214)

Uses Eclipse formatting tools with a configuration matching Google's style guide (plus our customisations).

Author: nickcmaynard

eclipse-formatter.xml

@@ -61,6 +61,14 @@
                     </execution>
                 </executions>
             </plugin>
+            <plugin>
+                <groupId>net.revelc.code</groupId>
+                <artifactId>formatter-maven-plugin</artifactId>
+                <configuration>
+                    <!-- Point at the eclipse-formatter.xml in the swagger-codegen parent project directory -->
+                    <configFile>${project.basedir}${file.separator}${project.parent.relativePath}${file.separator}eclipse-formatter.xml</configFile>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
 

modules/swagger-codegen-cli/pom.xml

@@ -83,5 +83,15 @@
                 </plugin>
             </plugins>
         </pluginManagement>
+        <plugins>
+            <plugin>
+                <groupId>net.revelc.code</groupId>
+                <artifactId>formatter-maven-plugin</artifactId>
+                <configuration>
+                    <!-- Point at the eclipse-formatter.xml in the swagger-codegen parent project directory -->
+                    <configFile>${project.basedir}${file.separator}${project.parent.relativePath}${file.separator}eclipse-formatter.xml</configFile>
+                </configuration>
+            </plugin>
+        </plugins>
     </build>
 </project>

modules/swagger-codegen-maven-plugin/pom.xml

@@ -110,6 +110,14 @@
                 <artifactId>maven-release-plugin</artifactId>
                  <version>2.5.3</version>
             </plugin>
+            <plugin>
+                <groupId>net.revelc.code</groupId>
+                <artifactId>formatter-maven-plugin</artifactId>
+                <configuration>
+                    <!-- Point at the eclipse-formatter.xml in the swagger-codegen parent project directory -->
+                    <configFile>${project.basedir}${file.separator}${project.parent.relativePath}${file.separator}eclipse-formatter.xml</configFile>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
     <profiles>

modules/swagger-codegen/pom.xml

@@ -119,6 +119,14 @@
                     </execution>
                 </executions>
             </plugin>
+            <plugin>
+                <groupId>net.revelc.code</groupId>
+                <artifactId>formatter-maven-plugin</artifactId>
+                <configuration>
+                    <!-- Point at the eclipse-formatter.xml in the swagger-codegen parent project directory -->
+                    <configFile>${project.basedir}${file.separator}${project.parent.relativePath}${file.separator}eclipse-formatter.xml</configFile>
+                </configuration>
+            </plugin>
         </plugins>
     </build>
     <dependencies>

modules/swagger-generator/pom.xml

@@ -67,6 +67,26 @@
         <directory>target</directory>
         <finalName>${project.artifactId}-${project.version}</finalName>
         <plugins>
+            <plugin>
+                <groupId>net.revelc.code</groupId>
+                <artifactId>formatter-maven-plugin</artifactId>
+                <!-- Uncomment this to format before checkstyle -->
+                <!-- <executions>
+                    <execution>
+                        <id>format</id>
+                        <phase>validate</phase>
+                        <goals>
+                            <goal>format</goal>
+                        </goals>
+                    </execution>
+                </executions> -->
+                <configuration>
+                    <compilerSource>1.7</compilerSource>
+                    <compilerCompliance>1.7</compilerCompliance>
+                    <compilerTargetPlatform>1.7</compilerTargetPlatform>
+                    <lineEnding>LF</lineEnding>
+                </configuration>
+            </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-checkstyle-plugin</artifactId>
@@ -77,6 +97,8 @@
                         <phase>validate</phase>
                         <configuration>
                             <configLocation>google_checkstyle.xml</configLocation>
+                            <!-- Don't include generated sources a la http://stackoverflow.com/a/30406454 -->
+                            <sourceDirectory>${project.build.sourceDirectory}</sourceDirectory>
                             <encoding>UTF-8</encoding>
                             <consoleOutput>true</consoleOutput>
                             <failsOnError>true</failsOnError>
@@ -201,6 +223,15 @@
                 </executions>
             </plugin>
         </plugins>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>net.revelc.code</groupId>
+                    <artifactId>formatter-maven-plugin</artifactId>
+                    <version>0.5.2</version>
+                </plugin>
+            </plugins>
+        </pluginManagement>
     </build>
     <profiles>
         <profile>