Class MethodLengthCheck

  • All Implemented Interfaces:
    Configurable, Contextualizable

    public class MethodLengthCheck
    extends AbstractCheck

    Checks for long methods and constructors.

    Rationale: If a method becomes very long it is hard to understand. Therefore long methods should usually be refactored into several individual methods that focus on a specific task.

    • Property max - Specify the maximum number of lines allowed. Type is int. Default value is 150.
    • Property countEmpty - Control whether to count empty lines and single line comments of the form //. Type is boolean. Default value is true.
    • Property tokens - tokens to check Type is java.lang.String[]. Validation type is tokenSet. Default value is: METHOD_DEF, CTOR_DEF, COMPACT_CTOR_DEF.

    To configure the check:

     <module name="MethodLength"/>
     

    To configure the check so that it accepts methods with at most 60 lines:

     <module name="MethodLength">
       <property name="tokens" value="METHOD_DEF"/>
       <property name="max" value="60"/>
     </module>
     

    To configure the check so that it accepts methods with at most 60 lines, not counting empty lines and single line comments:

     <module name="MethodLength">
       <property name="tokens" value="METHOD_DEF"/>
       <property name="max" value="60"/>
       <property name="countEmpty" value="false"/>
     </module>
     

    Parent is com.puppycrawl.tools.checkstyle.TreeWalker

    Violation Message Keys:

    • maxLen.method
    Since:
    3.0
    • Field Detail

      • MSG_KEY

        public static final java.lang.String MSG_KEY
        A key is pointing to the warning message text in "messages.properties" file.
        See Also:
        Constant Field Values
      • DEFAULT_MAX_LINES

        private static final int DEFAULT_MAX_LINES
        Default maximum number of lines.
        See Also:
        Constant Field Values
      • countEmpty

        private boolean countEmpty
        Control whether to count empty lines and single line comments of the form //.
      • max

        private int max
        Specify the maximum number of lines allowed.
    • Constructor Detail

      • MethodLengthCheck

        public MethodLengthCheck()
    • Method Detail

      • getDefaultTokens

        public int[] getDefaultTokens()
        Description copied from class: AbstractCheck
        Returns the default token a check is interested in. Only used if the configuration for a check does not define the tokens.
        Specified by:
        getDefaultTokens in class AbstractCheck
        Returns:
        the default tokens
        See Also:
        TokenTypes
      • getAcceptableTokens

        public int[] getAcceptableTokens()
        Description copied from class: AbstractCheck
        The configurable token set. Used to protect Checks against malicious users who specify an unacceptable token set in the configuration file. The default implementation returns the check's default tokens.
        Specified by:
        getAcceptableTokens in class AbstractCheck
        Returns:
        the token set this check is designed for.
        See Also:
        TokenTypes
      • getRequiredTokens

        public int[] getRequiredTokens()
        Description copied from class: AbstractCheck
        The tokens that this check must be registered for.
        Specified by:
        getRequiredTokens in class AbstractCheck
        Returns:
        the token set this must be registered for.
        See Also:
        TokenTypes
      • getLengthOfBlock

        private int getLengthOfBlock​(DetailAST openingBrace,
                                     DetailAST closingBrace)
        Returns length of code only without comments and blank lines.
        Parameters:
        openingBrace - block opening brace
        closingBrace - block closing brace
        Returns:
        number of lines with code for current block
      • setMax

        public void setMax​(int length)
        Setter to specify the maximum number of lines allowed.
        Parameters:
        length - the maximum length of a method.
      • setCountEmpty

        public void setCountEmpty​(boolean countEmpty)
        Setter to control whether to count empty lines and single line comments of the form //.
        Parameters:
        countEmpty - whether to count empty and single line comments of the form //.