Package com.puppycrawl.tools.checkstyle.checks.coding

Class ReturnCountCheck

  • All Implemented Interfaces:
    Configurable, Contextualizable
    public final class ReturnCountCheck
extends AbstractCheck

    Restricts the number of return statements in methods, constructors and lambda expressions. Ignores specified methods (equals by default).

    max property will only check returns in methods and lambdas that return a specific value (Ex: 'return 1;').

    maxForVoid property will only check returns in methods, constructors, and lambdas that have no return type (IE 'return;'). It will only count visible return statements. Return statements not normally written, but implied, at the end of the method/constructor definition will not be taken into account. To disallow "return;" in void return type methods, use a value of 0.

    Rationale: Too many return points can mean that code is attempting to do too much or may be difficult to understand.

    • Property max - Specify maximum allowed number of return statements in non-void methods/lambdas. Type is int. Default value is 2.
    • Property maxForVoid - Specify maximum allowed number of return statements in void methods/constructors/lambdas. Type is int. Default value is 1.
    • Property format - Specify method names to ignore. Type is java.util.regex.Pattern. Default value is "^equals$".
    • Property tokens - tokens to check Type is java.lang.String[]. Validation type is tokenSet. Default value is: CTOR_DEF, METHOD_DEF, LAMBDA.

    To configure the check so that it doesn't allow more than three return statements per method (ignoring the equals() method): 

     <module name="ReturnCount">
   <property name="max" value="3"/>
 </module>

    To configure the check so that it doesn't allow any return statements per void method: 

     <module name="ReturnCount">
   <property name="maxForVoid" value="0"/>
 </module>

    To configure the check so that it doesn't allow more than 2 return statements per method (ignoring the equals() method) and more than 1 return statements per void method: 

     <module name="ReturnCount">
   <property name="max" value="2"/>
   <property name="maxForVoid" value="1"/>
 </module>

    To configure the check so that it doesn't allow more than three return statements per method for all methods: 

     <module name="ReturnCount">
   <property name="max" value="3"/>
   <property name="format" value="^$"/>
 </module>

    To configure the check so that it doesn't allow any return statements in constructors, more than one return statement in all lambda expressions and more than two return statements in methods: 

     <module name="ReturnCount">
   <property name="max" value="0"/>
   <property name="tokens" value="CTOR_DEF"/>
 </module>
 <module name="ReturnCount">
   <property name="max" value="1"/>
   <property name="tokens" value="LAMBDA"/>
 </module>
 <module name="ReturnCount">
   <property name="max" value="2"/>
   <property name="tokens" value="METHOD_DEF"/>
 </module>

    Parent is com.puppycrawl.tools.checkstyle.TreeWalker

    Violation Message Keys:

    • return.count
    • return.countVoid
    Since:
    3.2

    • 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

      • MSG_KEY_VOID

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

    • Constructor Detail

      • ReturnCountCheck

        public ReturnCountCheck()

    • 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

      • 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

      • 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

      • setFormat

        public void setFormat​(java.util.regex.Pattern pattern)
        Setter to specify method names to ignore.
        Parameters:
        pattern - a pattern.

      • setMax

        public void setMax​(int max)
        Setter to specify maximum allowed number of return statements in non-void methods/lambdas.
        Parameters:
        max - maximum allowed number of return statements.

      • setMaxForVoid

        public void setMaxForVoid​(int maxForVoid)
        Setter to specify maximum allowed number of return statements in void methods/constructors/lambdas.
        Parameters:
        maxForVoid - maximum allowed number of return statements for void methods.

      • beginTree

        public void beginTree​(DetailAST rootAST)
        Description copied from class: AbstractCheck
        Called before the starting to process a tree. Ideal place to initialize information that is to be collected whilst processing a tree.
        Overrides:
        beginTree in class AbstractCheck
        Parameters:
        rootAST - the root of the tree

      • leaveToken

        public void leaveToken​(DetailAST ast)
        Description copied from class: AbstractCheck
        Called after all the child nodes have been process.
        Overrides:
        leaveToken in class AbstractCheck
        Parameters:
        ast - the token leaving