Package com.puppycrawl.tools.checkstyle.checks.imports

Class AvoidStarImportCheck

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

    Checks that there are no import statements that use the * notation.

    Rationale: Importing all classes from a package or static members from a class leads to tight coupling between packages or classes and might lead to problems when a new version of a library introduces name clashes.

    Note that property excludes is not recursive, subpackages of excluded packages are not automatically excluded.

    • Property excludes - Specify packages where star imports are allowed. Type is java.lang.String[]. Default value is "".
    • Property allowClassImports - Control whether to allow starred class imports like import java.util.*;. Type is boolean. Default value is false.
    • Property allowStaticMemberImports - Control whether to allow starred static member imports like import static org.junit.Assert.*;. Type is boolean. Default value is false.

    To configure the check: 

     <module name="AvoidStarImport"/>

    Example:

     import java.util.Scanner;         // OK
 import java.io.*;                 // violation
 import static java.lang.Math.*;   // violation
 import java.util.*;               // violation
 import java.net.*;                // violation

    To configure the check so that star imports from packages java.io and java.net as well as static members from class java.lang.Math are allowed: 

     <module name="AvoidStarImport">
   <property name="excludes" value="java.io,java.net,java.lang.Math"/>
 </module>

    Example:

     import java.util.Scanner;         // OK
 import java.io.*;                 // OK
 import static java.lang.Math.*;   // OK
 import java.util.*;               // violation
 import java.net.*;                // OK

    To configure the check so that star imports from all packages are allowed: 

     <module name="AvoidStarImport">
   <property name="allowClassImports" value="true"/>
 </module>

    Example:

     import java.util.Scanner;         // OK
 import java.io.*;                 // OK
 import static java.lang.Math.*;   // violation
 import java.util.*;               // OK
 import java.net.*;                // OK

    To configure the check so that starred static member imports from all packages are allowed: 

     <module name="AvoidStarImport">
   <property name="allowStaticMemberImports" value="true"/>
 </module>

    Example:

     import java.util.Scanner;         // OK
 import java.io.*;                 // violation
 import static java.lang.Math.*;   // OK
 import java.util.*;               // violation
 import java.net.*;                // violation

    Parent is com.puppycrawl.tools.checkstyle.TreeWalker

    Violation Message Keys:

    • import.avoidStar
    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

    • Constructor Detail

      • AvoidStarImportCheck

        public AvoidStarImportCheck()

    • 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

      • setExcludes

        public void setExcludes​(java.lang.String... excludesParam)
        Setter to specify packages where star imports are allowed.
        Parameters:
        excludesParam - a list of package names/fully-qualifies class names where star imports are ok.

      • setAllowClassImports

        public void setAllowClassImports​(boolean allow)
        Setter to control whether to allow starred class imports like import java.util.*;.
        Parameters:
        allow - true to allow false to disallow

      • setAllowStaticMemberImports

        public void setAllowStaticMemberImports​(boolean allow)
        Setter to control whether to allow starred static member imports like import static org.junit.Assert.*;.
        Parameters:
        allow - true to allow false to disallow