scalastyle.xml

<?xml version="1.0" encoding="UTF-8"?>
<scalastyle>

  <check level="warn" class="org.scalastyle.scalariform.NoFinalizeChecker" enabled="true"></check>

  <check level="warn" class="org.scalastyle.scalariform.CovariantEqualsChecker"
         enabled="true"></check>

  <check level="warn" class="org.scalastyle.scalariform.NonASCIICharacterChecker"
         enabled="true"></check>

  <check level="warn" class="org.scalastyle.file.FileLineLengthChecker" enabled="true">
    <parameters>
      <parameter name="maxLineLength">120</parameter>
      <parameter name="tabSize">2</parameter>
      <parameter name="ignoreImports">true</parameter>
    </parameters>
  </check>

  <check customId="println" level="warning" class="org.scalastyle.scalariform.TokenChecker"
         enabled="true">
    <parameters>
      <parameter name="regex">^println$</parameter>
    </parameters>
    <customMessage><![CDATA[Are you sure you want to println? If yes, wrap the code block with
      // scalastyle:off println
      println(...)
      // scalastyle:on println]]></customMessage>
  </check>

  <check customId="printStackTrace" level="warning" class="org.scalastyle.scalariform.TokenChecker"
         enabled="true">
    <parameters>
      <parameter name="regex">^printStackTrace$</parameter>
    </parameters>
    <customMessage><![CDATA[Are you sure you want to use printStackTrace$? Consider logging instead.
     Or wrap the code block with
      // scalastyle:off printStackTrace
      println(...)
      // scalastyle:on printStackTrace]]></customMessage>
  </check>

  <check customId="javaconversions" level="warn" class="org.scalastyle.scalariform.TokenChecker"
         enabled="true">
    <parameters>
      <parameter name="regex">JavaConversions</parameter>
    </parameters>
    <customMessage>Instead of importing implicits in scala.collection.JavaConversions._, import
      scala.collection.JavaConverters._ and use .asScala / .asJava methods
    </customMessage>
  </check>

  <check level="error" class="org.scalastyle.file.HeaderMatchesChecker" enabled="true">
    <parameters>
      <parameter name="header"><![CDATA[/*
 * Copyright 2018 PayPal Inc.
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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
 *
 *    http://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.
 */]]></parameter>
    </parameters>
  </check>

  <check level="error" class="org.scalastyle.file.FileTabChecker" enabled="true"></check>

  <check level="error" class="org.scalastyle.scalariform.SpacesAfterPlusChecker"
         enabled="true"></check>

  <check level="error" class="org.scalastyle.scalariform.SpacesBeforePlusChecker"
         enabled="true"></check>

  <check level="error" class="org.scalastyle.file.WhitespaceEndOfLineChecker"
         enabled="true"></check>

  <check level="error" class="org.scalastyle.scalariform.ClassNamesChecker" enabled="true">
    <parameters>
      <parameter name="regex"><![CDATA[[A-Z][A-Za-z]*]]></parameter>
    </parameters>
  </check>

  <check level="error" class="org.scalastyle.scalariform.ObjectNamesChecker" enabled="true">
    <parameters>
      <parameter name="regex"><![CDATA[[A-Z][A-Za-z]*]]></parameter>
    </parameters>
  </check>

  <check level="error" class="org.scalastyle.scalariform.PackageObjectNamesChecker" enabled="true">
    <parameters>
      <parameter name="regex"><![CDATA[^[a-z][A-Za-z]*$]]></parameter>
    </parameters>
  </check>

  <check level="error" class="org.scalastyle.scalariform.ParameterNumberChecker" enabled="true">
    <parameters>
      <parameter name="maxParameters"><![CDATA[15]]></parameter>
    </parameters>
  </check>

  <check level="error" class="org.scalastyle.scalariform.StructuralTypeChecker"
         enabled="true"></check>

  <check level="error" class="org.scalastyle.scalariform.UppercaseLChecker" enabled="true"></check>

  <check level="error" class="org.scalastyle.scalariform.IfBraceChecker" enabled="true">
    <parameters>
      <parameter name="singleLineAllowed"><![CDATA[true]]></parameter>
      <parameter name="doubleLineAllowed"><![CDATA[true]]></parameter>
    </parameters>
  </check>

  <check level="error" class="org.scalastyle.scalariform.PublicMethodsHaveTypeChecker"
         enabled="true"></check>

  <check level="error" class="org.scalastyle.file.NewLineAtEofChecker" enabled="true"></check>

  <check level="error" class="org.scalastyle.scalariform.SpaceAfterCommentStartChecker"
         enabled="true"></check>

  <check level="error" class="org.scalastyle.scalariform.EnsureSingleSpaceBeforeTokenChecker"
         enabled="true">
    <parameters>
      <parameter name="tokens">ARROW, EQUALS, ELSE, TRY, CATCH, FINALLY, LARROW, RARROW</parameter>
    </parameters>
  </check>

  <check level="error" class="org.scalastyle.scalariform.EnsureSingleSpaceAfterTokenChecker"
         enabled="true">
    <parameters>
      <parameter name="tokens">ARROW, EQUALS, COMMA, COLON, IF, ELSE, DO, WHILE, FOR, MATCH, TRY,
        CATCH, FINALLY, LARROW, RARROW
      </parameter>
    </parameters>
  </check>

  <!-- ??? usually shouldn't be checked into the code base. -->
  <check level="error" class="org.scalastyle.scalariform.NotImplementedErrorUsage"
         enabled="true"></check>


  <check level="error" class="org.scalastyle.scalariform.ImportOrderChecker" enabled="true">
    <parameters>
      <parameter name="groups">java,scala,3rdParty,gimel</parameter>
      <parameter name="group.java">javax?\..*</parameter>
      <parameter name="group.scala">scala\..*</parameter>
      <parameter name="group.3rdParty">(?!com\.paypal.gimel\.).*</parameter>
      <parameter name="group.gimel">com\.paypal\.gimel\..*</parameter>
    </parameters>
  </check>

  <check level="error" class="org.scalastyle.scalariform.DisallowSpaceBeforeTokenChecker"
         enabled="true">
    <parameters>
      <parameter name="tokens">COMMA</parameter>
    </parameters>
  </check>

  <check level="error" class="org.scalastyle.scalariform.EqualsHashCodeChecker"
         enabled="true"></check>

  <check level="error" class="org.scalastyle.scalariform.NoWhitespaceBeforeLeftBracketChecker"
         enabled="true"></check>

  <check level="error" class="org.scalastyle.scalariform.NoWhitespaceAfterLeftBracketChecker"
         enabled="true"></check>

</scalastyle>