Class NewlineAtEndOfFileCheck

java.lang.Object
com.puppycrawl.tools.checkstyle.AbstractAutomaticBean
com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck
com.puppycrawl.tools.checkstyle.checks.NewlineAtEndOfFileCheck
All Implemented Interfaces:
Configurable, Contextualizable, FileSetCheck
public class NewlineAtEndOfFileCheck extends AbstractFileSetCheck
Checks whether files end with a line separator.

Rationale: Any not empty source files and text files in general should end with a line separator to let other easily add new content at the end of file and "diff" command does not show previous lines as changed.

Example (the line with 'No newline at end of file' should not be in the diff): 

@@ -32,4 +32,5 @@ ForbidWildcardAsReturnTypeCheck.returnTypeClassNamesIgnoreRegex
PublicReferenceToPrivateTypeCheck.name = Public Reference To Private Type

StaticMethodCandidateCheck.name = Static Method Candidate
-StaticMethodCandidateCheck.desc = Checks whether private methods should be declared as static.
\ No newline at end of file
+StaticMethodCandidateCheck.desc = Checks whether private methods should be declared as static.
+StaticMethodCandidateCheck.skippedMethods = Method names to skip during the check.

It can also trick the VCS to report the wrong owner for such lines. An engineer who has added nothing but a newline character becomes the last known author for the entire line. As a result, a mate can ask him a question to which he will not give the correct answer.

Old Rationale: CVS source control management systems will even print a warning when it encounters a file that doesn't end with a line separator.

Attention: property fileExtensions works with files that are passed by similar property for at Checker. Please make sure required file extensions are mentioned at Checker's fileExtensions property.

Notes: This will check against the platform-specific default line separator.

This check verifies only the presence of a single line separator at the end of the file. It does not report violations for multiple trailing blank lines or additional newline characters beyond the final separator.

It is also possible to enforce the use of a specific line-separator across platforms, with the lineSeparator property.

Since:
3.1

  • Field Details

    • MSG_KEY_UNABLE_OPEN

      public static final String MSG_KEY_UNABLE_OPEN
      A key is pointing to the warning message text in "messages.properties" file.
      See Also:

    • MSG_KEY_NO_NEWLINE_EOF

      public static final String MSG_KEY_NO_NEWLINE_EOF
      A key is pointing to the warning message text in "messages.properties" file.
      See Also:

    • MSG_KEY_WRONG_ENDING

      public static final String MSG_KEY_WRONG_ENDING
      A key is pointing to the warning message text in "messages.properties" file.
      See Also:

    • lineSeparator

      private LineSeparatorOption lineSeparator
      Specify the type of line separator.

  • Constructor Details

    • NewlineAtEndOfFileCheck

      public NewlineAtEndOfFileCheck()

  • Method Details

    • processFiltered

      protected void processFiltered(File file, FileText fileText)
      Description copied from class: AbstractFileSetCheck
      Called to process a file that matches the specified file extensions.
      Specified by:
      processFiltered in class AbstractFileSetCheck
      Parameters:
      file - the file to be processed
      fileText - the contents of the file.

    • setLineSeparator

      public void setLineSeparator(String lineSeparatorParam)
      Setter to specify the type of line separator.
      Parameters:
      lineSeparatorParam - The line separator to set
      Throws:
      IllegalArgumentException - If the specified line separator is not one of 'crlf', 'lf', 'cr', 'lf_cr_crlf' or 'system'
      Since:
      3.1

    • readAndCheckFile

      private void readAndCheckFile(File file) throws IOException
      Reads the file provided and checks line separators.
      Parameters:
      file - the file to be processed
      Throws:
      IOException - When an IO error occurred while reading from the file provided

    • endsWithNewline

      private static boolean endsWithNewline(RandomAccessFile file, LineSeparatorOption separator) throws IOException
      Checks whether the content provided by the Reader ends with the platform specific line separator.
      Parameters:
      file - The reader for the content to check
      separator - The line separator
      Returns:
      boolean Whether the content ends with a line separator
      Throws:
      IOException - When an IO error occurred while reading from the provided reader