checkstyle.xml

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
          "-//Checkstyle//DTD Checkstyle Configuration 1.3//EN"
          "https://checkstyle.org/dtds/configuration_1_3.dtd">

<module name="Checker">
  
  <module name="TreeWalker">
    
<!-- Class Design -->
    
<!-- Makes 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>
<!-- Checks that each top-level class, interface, enum or annotation resides in a source file of its own. -->
    <module name="OneTopLevelClass"/>
    
<!-- Coding -->
    
<!-- Checks that classes and records which define a covariant equals() method also override method equals(Object). -->
    <module name="CovariantEquals"/>
<!-- Checks that classes that either override equals() or hashCode() also overrides the other.  -->
    <module name="EqualsHashCode"/>
<!-- Detects empty statements (standalone ";" semicolon). Empty statements often introduce bugs that are hard to spot -->
    <module name="EmptyStatement">
      <property name="severity" value="warning"/>
    </module>
<!-- Checks that any combination of String literals is on the left side of an equals() comparison. -->
    <module name="EqualsAvoidNull">
      <property name="severity" value="warning"/>
    </module>
<!-- Checks that local variables that never have their values changed are declared final. -->
    <module name="FinalLocalVariable">
      <property name="severity" value="warning"/>
      <property name="tokens" value="VARIABLE_DEF,PARAMETER_DEF"/>
    </module>
<!-- Checks that a local variable or a parameter does not shadow a field that is defined in the same class.  -->
    <module name="HiddenField">
      <property name="severity" value="warning"/>
      <property name="ignoreConstructorParameter" value="true"/>
      <property name="ignoreSetter" value="true"/>
      <property name="tokens" value="VARIABLE_DEF"/>
    </module>
<!-- For performance reasons, it is preferable to use the predefined constants TRUE and FALSE respect Boolean instance. -->
    <module name="IllegalInstantiation">
      <property name="classes" value="java.lang.Boolean"/>
    </module>
<!-- Checks for illegal tokens. By default labels are prohibited. -->
    <module name="IllegalToken">
      <property name="tokens" value="LITERAL_NATIVE"/>
    </module>
<!-- Checks for assignments in subexpressions, such as in String s = Integer.toString(i = 2);. -->
    <module name="InnerAssignment">
      <property name="severity" value="warning"/>
    </module>
<!-- Checks that for loop control variables are not modified inside the for block. An example is: for (int i = 0; i < 1; i++) { i++; //violation } -->
    <module name="ModifiedControlVariable"/>
<!-- Checks for over-complicated boolean expressions. Currently finds code like if (b == true), b || true, !false, etc. -->
    <module name="SimplifyBooleanExpression"/>
<!-- Checks for over-complicated boolean return statements. For example the following code: if (valid()) return false; else return true; -->
    <module name="SimplifyBooleanReturn"/>
<!-- Checks that string literals are not used with == or !=. Since == will compare the object references, not the actual value of the strings, String.equals() should be used. -->
    <module name="StringLiteralEquality"/>
<!-- Checks that certain exception types do not appear in a catch statement. -->
    <module name="IllegalCatch">
      <property name="illegalClassNames" value="java.lang.Throwable, java.lang.RuntimeException"/>
    </module>
<!-- Ensures that a class has a package declaration, and (optionally) whether the package name matches the directory name for the source file. -->
    <module name="PackageDeclaration"/>
<!-- Checks that each variable declaration is in its own statement and on its own line. -->
    <module name="MultipleVariableDeclarations"/>
<!-- Checks if unnecessary parentheses are used in a statement or expression. -->
    <module name="UnnecessaryParentheses">
      <property name="severity" value="warning"/>
    </module>
<!-- Checks that there is only one statement per line. Rationale: It's very difficult to read multiple statements on one line. -->
    <module name="OneStatementPerLine"/>
    
<!-- Miscellaneous -->
    
<!-- Detects uncommented main methods. Rationale: A main method is often used for debugging purposes. When debugging is finished, developers often forget to remove the method. -->
    <module name="UncommentedMain"/>
    
<!-- Complexity code  -->
    
<!-- Checks cyclomatic complexity against a specified limit. It is a measure of the minimum number of possible paths through the source and therefore the number of required tests, it is not a about quality of code! It is only applied to methods, c-tors, static initializers and instance initializers. -->
    <module name="CyclomaticComplexity">
      <property name="severity" value="warning"/>
      <property name="max" value="30"/>
    </module>
<!-- Restricts the number of boolean operators in an expression. Rationale: Too many conditions leads to code that is difficult to read and hence debug and maintain. -->
    <module name="BooleanExpressionComplexity">
      <property name="severity" value="warning"/>
      <property name="max" value="5"/>
    </module>
<!-- Checks the NPATH complexity against a specified limit. The NPATH metric computes the number of possible execution paths through a function(method). It takes into account the nesting of conditional statements and multi-part boolean expressions. -->
    <module name="NPathComplexity">
      <property name="severity" value="warning"/>
    </module>
    
<!-- Naming Conventions -->
    
<!-- Checks that package names conform to a specified pattern.-->
    <module name="PackageName">
      <property name="format" value="^org.dew.[a-z0-9]+(\.[a-zA-Z_][a-zA-Z0-9_]*)*$"/>
    </module>
<!-- Checks that constant names conform to a specified pattern. -->
    <module name="ConstantName">
      <property name="severity" value="warning"/>
      <property name="format" value="^[A-Z][A-Z0-9_]*$"/>
    </module>
<!-- Checks that class names conform to a specified pattern. -->
    <module name="TypeName">
      <property name="format" value="^[A-Z][a-zA-Z0-9_]*$"/>
      <property name="tokens" value="CLASS_DEF"/>
    </module>
<!-- Checks that interface names conform to a specified pattern. -->
    <module name="TypeName">
      <property name="format" value="^I[A-Z][a-zA-Z0-9_]*$"/>
      <property name="tokens" value="INTERFACE_DEF"/>
    </module>
<!-- Checks location of annotation on language elements. -->
    <module name="AnnotationLocation">
      <property name="allowSamelineMultipleAnnotations" value="false"/>
      <property name="allowSamelineSingleParameterlessAnnotation" value="true"/>
    </module>
    
  </module>
  
</module>