checkstyle.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
          "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
          "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">

<module name="Checker">
    <!-- Checks for Size Violations -->
    <!-- See http://checkstyle.sourceforge.net/config_sizes.html -->
    <!-- ************************** -->
    <module name="LineLength">
        <property name="severity" value="warning"/>
        <property name="max" value="150"/>
    </module>

    <module name="SuppressionFilter">
        <property name="file" value="${config_loc}/suppressions.xml"/>
    </module>
          
    <!-- Configures filter to suppress audit events for annotations -->
    <!-- See https://checkstyle.sourceforge.io/config_filters.html#SuppressionFilter -->
    <module name="SuppressWarningsFilter" />

    <!-- Checks whether files end with a new line. -->
    <!-- See http://checkstyle.sourceforge.net/config_misc.html#NewlineAtEndOfFile -->
    <module name="NewlineAtEndOfFile">
         <property name="fileExtensions" value="java,gradle,xml,txt,prefab"/>
    </module>

    <!-- Checks that there are no tab characters ('\t') in the source code. -->
    <!-- See http://checkstyle.sourceforge.net/config_whitespace.html#FileTabCharacter -->
    <module name="FileTabCharacter">
        <property name="eachLine" value="true"/>
        <property name="fileExtensions" value="java"/>
    </module>

    <!-- Checks for header --> 
    <!-- See http://checkstyle.sourceforge.net/config_header.html --> 
    <!-- ***************** --> 
    <!-- Checks that a source file begins with a specified header. --> 
    <module name="RegexpHeader">
        <property name="severity" value="warning"/>
        <property name="header" value="// Copyright 20\d\d The Terasology Foundation\n// SPDX-License-Identifier: Apache-2.0"/>
        <property name="fileExtensions" value="java"/>
    </module>
  
    <!-- Disallow author names and auto-generated tags -->
    <!-- 
        TODO: replace with proper JavaDoc checks as soon as they work properly.
           See https://github.com/checkstyle/checkstyle/issues/952         
           See https://github.com/checkstyle/checkstyle/issues/2506          
    -->
    <module name="RegexpSingleline">
        <property name="severity" value="warning"/>
        <property name="format" value="^\s*\*\s*@author"/>
        <property name="fileExtensions" value="java"/>
        <property name="message" value="Author tags are not allowed"/>
    </module>
    
    <!-- Disallow empty JavaDoc -->
    <module name="RegexpMultiline">
        <property name="severity" value="warning" />
        <property name="format" value="(\/\*\*)(\s|\*)*(\*\/)" />
        <property name="fileExtensions" value="java" />
        <property name="message" value="Empty JavaDoc" />
    </module>

    <module name="TreeWalker">
        <!-- Makes the annotations available to the filter. -->
        <module name="SuppressWarningsHolder" />
              
        <!-- Checks for Naming Conventions -->
        <!-- See http://checkstyle.sourceforge.net/config_naming.html -->
        <!-- ***************************** -->
        <!-- class type parameters : ^[A-Z]*$ -->
        <module name="ClassTypeParameterName">
            <property name="format" value="^[A-Z]*$"/>
        </module>
        <!-- constants (static, final fields) : ^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$ -->
        <!-- Unfortunately this module is too inclusive - static final fields are not necessarily constants! -->
        <module name="ConstantName">
            <property name="format" value="^([A-Z][A-Z0-9]*(_[A-Z0-9]+)*|logger)$"/>
            <property name="severity" value="info"/>
        </module>
        <!-- local, final variables, including catch parameters : ^[a-z][a-zA-Z0-9]*$ -->
        <module name="LocalFinalVariableName"/>
        <!-- local, non-final variables, including catch parameters : ^[a-z][a-zA-Z0-9]*$ -->
        <module name="LocalVariableName"/>
        <!-- non-static fields : ^[a-z][a-zA-Z0-9]*$ -->
        <module name="MemberName"/>
        <!-- methods : ^[a-z][a-zA-Z0-9]*$ -->
        <module name="MethodName"/>
        <!-- method type parameters : ^[A-Z]*$ -->
        <module name="MethodTypeParameterName">
            <property name="format" value="^[A-Z]*$"/>
        </module>
        <!-- packages : ^[a-z]+(\.[a-zA-Z_][a-zA-Z0-9_]*)*$ -->
        <module name="PackageName"/>
        <!-- parameters : ^[a-z][a-zA-Z0-9]*$ -->
        <module name="ParameterName"/>
        <!-- static, non-final fields : ^[a-z][a-zA-Z0-9]*$ -->
        <module name="StaticVariableName"/>
        <!-- classes and interfaces : ^[A-Z][a-zA-Z0-9]*$ -->
        <module name="TypeName"/>

        <!-- Checks for imports -->
        <!-- See http://checkstyle.sourceforge.net/config_imports.html -->
        <!-- ****************** -->
        <!-- Checks that there are no import statements that use the * notation. -->
        <!-- See http://checkstyle.sourceforge.net/config_imports.html#AvoidStarImport -->
        <module name="AvoidStarImport">
            <property name="severity" value="warning"/>
            <!-- allow starred static member imports -->
            <property name="allowStaticMemberImports" value="true"/>
            <property name="excludes" value="java.awt,javax.swing"/>
        </module>
        <!-- Checks for redundant import statements. -->
        <!-- See http://checkstyle.sourceforge.net/config_imports.html#RedundantImport -->
        <module name="RedundantImport">
            <property name="severity" value="warning"/>
        </module>
        <!-- Checks for unused import statements. -->
        <!-- See http://checkstyle.sourceforge.net/config_imports.html#UnusedImports -->
        <module name="UnusedImports">
            <property name="severity" value="warning"/>
        </module>
        <!-- Checks for banned packages, sun.* by default. -->
        <!-- See http://checkstyle.sourceforge.net/config_imports.html#IllegalImport -->
        <module name="IllegalImport"/>

        <!-- Checks for the number of types declared at the outer (or root) level in a file. -->
        <module name="OuterTypeNumber"/>

        <!-- Checks for whitespaces -->
        <!-- See http://checkstyle.sourceforge.net/config_whitespace.html -->
        <!-- ********************** -->
        <!-- Checks the padding of an empty for iterator; that is whether a space is required at an empty for iterator, or such spaces are forbidden. -->
        <module name="EmptyForIteratorPad">
            <property name="severity" value="warning"/>
        </module>
        <!-- Checks the padding between the identifier of a method definition, constructor definition, method call, or constructor invocation; and the left parenthesis of the parameter list. -->
        <module name="MethodParamPad">
            <property name="severity" value="warning"/>
        </module>
        <!-- Checks that there is no whitespace after a token. -->
        <module name="NoWhitespaceAfter">
            <property name="severity" value="warning"/>
        </module>
        <!-- Checks that there is no whitespace before a token. -->
        <module name="NoWhitespaceBefore">
            <property name="severity" value="warning"/>
        </module>
        <!-- Checks line wrapping for operators. -->
        <module name="OperatorWrap">
            <property name="severity" value="warning"/>
            <property name="tokens" value="BAND,BOR,BSR,BXOR,COLON,DIV,EQUAL,GE,GT,LAND,LE,LITERAL_INSTANCEOF,LOR,LT,MINUS,MOD,NOT_EQUAL,QUESTION,SL,SR,STAR"/>
        </module>
        <!-- Checks that the whitespace around the Generic tokens < and > is correct to the typical convention. -->
        <module name="GenericWhitespace">
            <property name="severity" value="warning"/>
        </module>
        <!-- Checks the policy on the padding of parentheses. -->
        <module name="ParenPad">
            <property name="severity" value="warning"/>
        </module>
        <!-- Checks the policy on the padding of parentheses for typecasts. -->
        <module name="TypecastParenPad">
            <property name="severity" value="warning"/>
        </module>
        <!-- Checks that a token is followed by whitespace. -->
        <module name="WhitespaceAfter">
            <property name="severity" value="warning"/>
        </module>
        <!-- Checks that a token is surrounded by whitespace. -->
        <module name="WhitespaceAround">
            <property name="severity" value="warning"/>
            <!-- We skip RCURLY because a false positive when it appears in annotations -->
            <property name="tokens" value="ASSIGN,BAND,BAND_ASSIGN,BOR,BOR_ASSIGN,BSR,BSR_ASSIGN,BXOR,BXOR_ASSIGN,COLON,DIV,DIV_ASSIGN,EQUAL,GE,GT,LAND,LCURLY,LE,LITERAL_CATCH,LITERAL_DO,LITERAL_ELSE,LITERAL_FINALLY,LITERAL_FOR,LITERAL_IF,LITERAL_RETURN,LITERAL_SYNCHRONIZED,LITERAL_TRY,LITERAL_WHILE,LOR,LT,MINUS,MINUS_ASSIGN,MOD,MOD_ASSIGN,NOT_EQUAL,PLUS,PLUS_ASSIGN,QUESTION,SL,SLIST,SL_ASSIGN,SR,SR_ASSIGN,STAR,STAR_ASSIGN"/>
        </module>

        <!-- Modifier Checks -->
        <!-- See http://checkstyle.sourceforge.net/config_modifier.html -->
        <!-- *************** -->
        <!-- Checks that the order of modifiers conforms to the suggestions in the Java Language specification -->
        <!-- See http://checkstyle.sourceforge.net/config_modifier.html#ModifierOrder -->
        <module name="ModifierOrder"/>
        <!-- Checks for redundant modifiers -->
        <!-- See http://checkstyle.sourceforge.net/config_modifier.html#RedundantModifier -->
        <module name="RedundantModifier">
            <property name="severity" value="warning"/>
        </module>

        <!-- Checks for blocks -->
        <!-- See http://checkstyle.sourceforge.net/config_blocks.html -->
        <!-- *************************************** -->
        <!-- Finds nested blocks, i.e. blocks that are used freely in the code. -->
        <!-- See http://checkstyle.sourceforge.net/config_blocks.html#AvoidNestedBlocks -->
        <module name="AvoidNestedBlocks">
            <property name="severity" value="warning"/>
            <property name="allowInSwitchCase" value="true"/>
        </module>
        <!-- Checks for empty blocks. -->
        <!-- See http://checkstyle.sourceforge.net/config_blocks.html#EmptyBlock -->
        <module name="EmptyBlock">
            <property name="severity" value="warning"/>
        </module>
        <!-- Checks for the placement of left curly braces ('{') for code blocks. Default: eol -->
        <!-- See http://checkstyle.sourceforge.net/config_blocks.html#LeftCurly -->
        <module name="LeftCurly"/>
        <!-- Checks for braces around code blocks. -->
        <!-- See http://checkstyle.sourceforge.net/config_blocks.html#NeedBraces -->
        <module name="NeedBraces"/>
        <!-- Checks the placement of right curly braces ('}') for else, try, and catch tokens. Default: same -->
        <!-- See http://checkstyle.sourceforge.net/config_blocks.html#RightCurly -->
        <module name="RightCurly"/>

        <!-- Checks for common coding problems -->
        <!-- See http://checkstyle.sourceforge.net/config_coding.html -->
        <!-- ********************************* -->
        <!-- Checks that classes that define a covariant equals() method also override method equals(java.lang.Object). -->
        <module name="CovariantEquals"/>
        <!-- Detects empty statements (standalone ;). -->
        <module name="EmptyStatement"/>
        <!-- Checks that classes that override equals() also override hashCode(). -->
        <module name="EqualsHashCode"/>
        <!-- Checks for assignments in subexpressions. -->
        <module name="InnerAssignment"/>
        <!-- Check for ensuring that for loop control variables are not modified inside the for block. -->
        <module name="ModifiedControlVariable"/>
        <!-- Checks for overly complicated boolean expressions. -->
        <module name="SimplifyBooleanExpression">
            <property name="severity" value="warning"/>
        </module>
        <!-- Checks for overly complicated boolean return statements. -->
        <module name="SimplifyBooleanReturn">
            <property name="severity" value="warning"/>
        </module>
        <!-- Checks that string literals are not used with == or !=.  -->
        <module name="StringLiteralEquality"/>
        <!-- This check can be used to ensure that types are not declared to be thrown. Declaring to throw java.lang.Error or java.lang.RuntimeException is almost never acceptable. -->
        <module name="IllegalThrows">
            <property name="severity" value="warning"/>
        </module>
        <!-- Ensure a class is has a package declaration, and (optionally) whether the package name matches the directory name for the source file. -->
        <module name="PackageDeclaration"/>
        <!-- Checks that particular class are never used as types in variable declarations, return values or parameters. Includes a pattern check that by default disallows abstract classes. -->
        <module name="IllegalType">
            <property name="severity" value="warning"/>
        </module>
        <!-- Checks for the order of the parts of a class. -->
        <module name="DeclarationOrder">
            <property name="severity" value="warning"/>
        </module>
        <!-- Disallow assignment of parameters. -->
        <module name="ParameterAssignment"/>
        <!-- Checks if any class or object member explicitly initialized to default for its type value. -->
        <module name="ExplicitInitialization">
           <property name="severity" value="ignore"/> <!-- 'ignore' because we often want to be explicit about initializations and belive the performance penalty is negligible -->
        </module>
        <!-- Check that the default is after all the cases in a switch statement. -->
        <module name="DefaultComesLast"/>
        <!-- Checks for fall through in switch statements Finds locations where a case contains Java code - but lacks a break, return, throw or continue statement. -->
        <module name="FallThrough"/>
        <!-- Checks that each variable declaration is in its own statement and on its own line. -->
        <module name="MultipleVariableDeclarations"/>
        <!-- Checks there is only one statement per line. -->
        <module name="OneStatementPerLine"/>

        <!-- Checks for class design -->
        <!-- See http://checkstyle.sourceforge.net/config_design.html -->
        <!-- *********************** -->
        <!-- Checks visibility of class members. Only static final members may be public. -->
        <!--
        <module name="VisibilityModifier">
            <property name="severity" value="warning"/>
        </module>
        -->
        <!-- Checks that a class which has only private constructors is declared as final. -->
        <module name="FinalClass">
            <property name="severity" value="warning"/>
        </module>
        <!-- Make sure that utility classes (classes that contain only static methods or fields in their API) do not have a public constructor. -->
        <module name="HideUtilityClassConstructor">
            <property name="severity" value="warning"/>
        </module>
        <!-- Use Interfaces only to define types. -->
        <module name="InterfaceIsType">
            <property name="severity" value="warning"/>
        </module>
        <!-- Ensures that exceptions are immutable. -->
        <module name="MutableException"/>
        <!-- Check nested (internal) classes/interfaces are declared at the bottom of the class after all method and field declarations. -->
        <module name="InnerTypeLast">
            <property name="severity" value="info"/>
        </module>

        <!-- Miscellaneous other checks -->
        <!-- See http://checkstyle.sourceforge.net/config_misc.html -->
        <!-- *************************** -->
        <!-- Checks the style of array type definitions. -->
        <!-- See http://checkstyle.sourceforge.net/config_misc.html#ArrayTypeStyle -->
        <module name="ArrayTypeStyle">
            <property name="severity" value="warning"/>
        </module>
        <!-- Checks correct indentation of Java Code. -->
        <!-- See http://checkstyle.sourceforge.net/config_misc.html#Indentation -->
        <!-- Disabled because it is buggy + unreasonable -->
        <!--<module name="Indentation">
            <property name="severity" value="info"/>
        </module>-->
        <!-- Checks that long constants are defined with an upper ell. That is ' L' and not 'l'. -->
        <!-- See http://checkstyle.sourceforge.net/config_misc.html#UpperEll -->
        <module name="UpperEll"/>
        <!-- Checks that the outer type name and the file name match. -->
        <!-- See http://checkstyle.sourceforge.net/config_misc.html#OuterTypeFilename -->
        <module name="OuterTypeFilename"/>

        <!-- Checks for annotations -->
        <!-- See http://checkstyle.sourceforge.net/config_annotation.html -->
        <!-- ********************** -->
        <!-- This check controls the style with the usage of annotations. -->
        <module name="AnnotationUseStyle">
            <property name="severity" value="warning"/>
        </module>
        <!-- Verifies that both the java.lang.Deprecated annotation is present and the @deprecated Javadoc tag is present when either is present. -->
        <module name="MissingDeprecated">
            <property name="severity" value="warning"/>
        </module>
        <!-- Verifies that the java.lang.Override annotation is present when the {@inheritDoc} javadoc tag is present. -->
        <module name="MissingOverride">
            <property name="severity" value="warning"/>
        </module>
    </module>
</module>