Add sbt-java-formatter for java code formatting.

project/JavaFormatter.scala

@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2019 Lightbend Inc. <https://www.lightbend.com>
+ */
+
+import akka.ProjectFileIgnoreSupport
+import com.lightbend.sbt.JavaFormatterPlugin
+import sbt.{AutoPlugin, PluginTrigger, Plugins}
+
+object JavaFormatter extends AutoPlugin with ProjectFileIgnoreSupport {
+
+  override def trigger = PluginTrigger.AllRequirements
+
+  override def requires: Plugins = JavaFormatterPlugin
+
+  final override protected val ignoreConfigFileName: String = ".sbt-java-formatter.conf"
+
+  final override protected val descriptor: String = "sbt-java-formatter"
+
+  import JavaFormatterPlugin.autoImport._
+  import sbt.Keys._
+  import sbt._
+  import sbt.io._
+
+  override def projectSettings: Seq[Def.Setting[_]] = Seq(
+    //below is for sbt java formatter
+    (excludeFilter in format) := {
+      val simpleFileFilter = new SimpleFileFilter(file => isIgnoredByFileOrPackages(file))
+      simpleFileFilter || (excludeFilter in format).value
+    }
+  )
+}