Enable build and format validation

Validate the formatting of Java files using GJF 1.7.
Output with formatting issues is provided as automated
commends to the code under review.

Change-Id: I2f31723c394c645b627ddf13b5f56e2fae96eb71

Jenkinsfile

diff --git a/Jenkinsfile b/Jenkinsfile
new file mode 100644
index 0000000..a090baf
--- /dev/null
+++ b/Jenkinsfile
@@ -0,0 +1,31 @@
+pipeline {
+    agent { label 'bazel-debian' }
+    stages {
+        stage('GJF') {
+            steps {
+                sh 'mvn process-sources'
+                script {
+                    def formatOut = sh (script: 'git status --porcelain', returnStdout: true)
+                    if (formatOut.trim()) {
+                        def files = formatOut.split('\n').collect { it.split(' ').last() }
+                        files.each { gerritComment path:it, message: 'Needs reformatting with GJF' }
+                        gerritReview labels: [Formatting: -1]
+                    } else {
+                        gerritReview labels: [Formatting: 1]
+                    }
+                }
+            }
+        }
+        stage('build') {
+            steps {
+                gerritReview labels: [Verified: 0], message: "Build started: ${env.BUILD_URL}"
+                sh 'mvn test'
+            }
+        }
+    }
+    post {
+        success { gerritReview labels: [Verified: 1] }
+        unstable { gerritReview labels: [Verified: 0], message: "Build is unstable: ${env.BUILD_URL}" }
+        failure { gerritReview labels: [Verified: -1], message: "Build failed: ${env.BUILD_URL}" }
+    }
+}

pom.xml

diff --git a/pom.xml b/pom.xml
index 9b8a945..98cf971 100644
--- a/pom.xml
+++ b/pom.xml
@@ -124,6 +124,30 @@
                     </execution>
                 </executions>
             </plugin>
+            <plugin>
+                <groupId>com.theoryinpractise</groupId>
+                <artifactId>googleformatter-maven-plugin</artifactId>
+                <version>1.7.3</version>
+                <executions>
+                    <execution>
+                        <id>reformat-sources</id>
+                        <configuration>
+                            <includeStale>false</includeStale>
+                            <style>GOOGLE</style>
+                            <formatMain>true</formatMain>
+                            <formatTest>true</formatTest>
+                            <filterModified>false</filterModified>
+                            <skip>false</skip>
+                            <fixImports>true</fixImports>
+                            <maxLineLength>100</maxLineLength>
+                        </configuration>
+                        <goals>
+                            <goal>format</goal>
+                        </goals>
+                        <phase>process-sources</phase>
+                    </execution>
+                </executions>
+            </plugin>
         </plugins>
     </build>