Class StringLiteralsConcatenationCheck

  • All Implemented Interfaces:
    com.puppycrawl.tools.checkstyle.api.Configurable, com.puppycrawl.tools.checkstyle.api.Contextualizable

    public final class StringLiteralsConcatenationCheck
    extends com.puppycrawl.tools.checkstyle.api.AbstractCheck
    Checks for not using concatenation of string literals in any form.

    The following constructs are prohibited:

     String a = "done in " + time + " seconds";
     System.out.println("File not found: " + file);
     x += "done";
     

    You should avoid string concatenation at all cost. Why? There are two reasons: readability of the code and translateability. First of all it's difficult to understand how the text will look after concatenation, especially if the text is long and there are more than a few + operators. Second, you won't be able to translate your text to other languages later, if you don't have solid string literals.

    There are two alternatives to concatenation: StringBuilder and String.format(String,Object[]).

    Since:
    0.3
    • Nested Class Summary

      • Nested classes/interfaces inherited from class com.puppycrawl.tools.checkstyle.AbstractAutomaticBean

        com.puppycrawl.tools.checkstyle.AbstractAutomaticBean.OutputStreamOptions
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      int[] getAcceptableTokens()  
      int[] getDefaultTokens()  
      int[] getRequiredTokens()  
      void visitToken​(com.puppycrawl.tools.checkstyle.api.DetailAST ast)  
      • Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractCheck

        beginTree, clearViolations, destroy, finishTree, getFileContents, getFilePath, getLine, getLineCodePoints, getLines, getTabWidth, getTokenNames, getViolations, init, isCommentNodesRequired, leaveToken, log, log, log, setFileContents, setTabWidth, setTokens
      • Methods inherited from class com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter

        finishLocalSetup, getCustomMessages, getId, getMessageBundle, getSeverity, getSeverityLevel, setId, setSeverity
      • Methods inherited from class com.puppycrawl.tools.checkstyle.AbstractAutomaticBean

        configure, contextualize, getConfiguration, setupChild
    • Constructor Detail

      • StringLiteralsConcatenationCheck

        public StringLiteralsConcatenationCheck()
    • Method Detail

      • getDefaultTokens

        public int[] getDefaultTokens()
        Specified by:
        getDefaultTokens in class com.puppycrawl.tools.checkstyle.api.AbstractCheck
      • getAcceptableTokens

        public int[] getAcceptableTokens()
        Specified by:
        getAcceptableTokens in class com.puppycrawl.tools.checkstyle.api.AbstractCheck
      • getRequiredTokens

        public int[] getRequiredTokens()
        Specified by:
        getRequiredTokens in class com.puppycrawl.tools.checkstyle.api.AbstractCheck
      • visitToken

        public void visitToken​(com.puppycrawl.tools.checkstyle.api.DetailAST ast)
        Overrides:
        visitToken in class com.puppycrawl.tools.checkstyle.api.AbstractCheck