SuppressWithNearbyCommentFilter

Since Checkstyle 5.0

Description

Filter SuppressWithNearbyCommentFilter uses nearby comments to suppress audit events.

Rationale: Same as SuppressionCommentFilter. Whereas the SuppressionCommentFilter uses matched pairs of filters to turn on/off comment matching, SuppressWithNearbyCommentFilter uses single comments. This requires fewer lines to mark a region, and may be aesthetically preferable in some contexts.

Attention: This filter may only be specified within the TreeWalker module (<module name="TreeWalker"/>) and only applies to checks which are also defined within this module. To filter non-TreeWalker checks like RegexpSingleline, a SuppressWithPlainTextCommentFilter or similar filter must be used.

Notes

SuppressWithNearbyCommentFilter can suppress Checks that have Treewalker as parent module.

Properties

name description type default value since
checkC Control whether to check C style comments (/* ... */). boolean true 5.0
checkCPP Control whether to check C++ style comments (//). boolean true 5.0
checkFormat Specify check pattern to suppress. Pattern ".*" 5.0
commentFormat Specify comment pattern to trigger filter to begin suppression. Pattern "SUPPRESS CHECKSTYLE (\w+)" 5.0
idFormat Specify check ID pattern to suppress. Pattern null 8.24
influenceFormat Specify negative/zero/positive value that defines the number of lines preceding/at/following the suppression comment. String "0" 5.0
messageFormat Define message pattern to suppress. Pattern null 5.0

Examples

To configure a filter to suppress audit events for check on any line with a comment SUPPRESS CHECKSTYLE check: 

<module name="Checker">
  <module name="TreeWalker">
    <module name="SuppressWithNearbyCommentFilter"/>
  </module>
</module>

Example:

private int [] array; // SUPPRESS CHECKSTYLE

To configure a filter to suppress all audit events on any line containing the comment CHECKSTYLE IGNORE THIS LINE: 

<module name="Checker">
  <module name="TreeWalker">
    <module name="SuppressWithNearbyCommentFilter">
      <property name="commentFormat" value="CHECKSTYLE IGNORE THIS LINE"/>
      <property name="checkFormat" value=".*"/>
      <property name="influenceFormat" value="0"/>
    </module>
  </module>
</module>

Example:

public static final int lowerCaseConstant; // CHECKSTYLE IGNORE THIS LINE

To configure a filter so that // OK to catch (Throwable|Exception|RuntimeException) here permits the current and previous line to avoid generating an IllegalCatch audit event: 

<module name="Checker">
  <module name="TreeWalker">
    <module name="SuppressWithNearbyCommentFilter">
      <property name="commentFormat" value="OK to catch (\w+) here"/>
      <property name="checkFormat" value="IllegalCatchCheck"/>
      <property name="messageFormat" value="$1"/>
      <property name="influenceFormat" value="-1"/>
    </module>
  </module>
</module>

Example:

. . .
catch (RuntimeException re) {
// OK to catch RuntimeException here
}
catch (Throwable th) { ... }
. . .

To configure a filter so that CHECKSTYLE IGNORE check FOR NEXTvar LINES avoids triggering any audits for the given check for the current line and the next var lines (for a total of var+1 lines): 

<module name="Checker">
  <module name="TreeWalker">
    <module name="SuppressWithNearbyCommentFilter">
      <property name="commentFormat"
          value="CHECKSTYLE IGNORE (\w+) FOR NEXT (\d+) LINES"/>
      <property name="checkFormat" value="$1"/>
      <property name="influenceFormat" value="$2"/>
    </module>
  </module>
</module>

Example:

static final int lowerCaseConstant; // CHECKSTYLE IGNORE ConstantNameCheck FOR NEXT 3 LINES
static final int lowerCaseConstant1;
static final int lowerCaseConstant2;
static final int lowerCaseConstant3;
static final int lowerCaseConstant4; // will warn here

To configure a filter to avoid any audits on code like: 

<module name="Checker">
  <module name="TreeWalker">
    <module name="SuppressWithNearbyCommentFilter">
      <property name="commentFormat"
        value="ALLOW (\\w+) ON PREVIOUS LINE"/>
      <property name="checkFormat" value="$1"/>
      <property name="influenceFormat" value="-1"/>
    </module>
  </module>
</module>

Example:

private int D2;
// ALLOW MemberName ON PREVIOUS LINE
. . .

To configure a filter to allow suppress one or more Checks (separated by "|") and demand comment no less than 14 symbols: 

<module name="Checker">
  <module name="TreeWalker">
    <module name="SuppressWithNearbyCommentFilter">
      <property name="commentFormat"
        value="@cs\.suppress \[(\w+(\|\w+)*)\] \w[-\.'`,:;\w ]{14,}"/>
      <property name="checkFormat" value="$1"/>
      <property name="influenceFormat" value="1"/>
    </module>
  </module>
</module>

Example:

public static final int [] array; // @cs.suppress [ConstantName|NoWhitespaceAfter] A comment here

It is possible to specify an ID of checks, so that it can be leveraged by the SuppressWithNearbyCommentFilter to skip validations. The following examples show how to skip validations near code that has comment like // @cs-: <ID/> (reason), where ID is the ID of checks you want to suppress.

Example of Checkstyle checks and SuppressWithNearbyCommentFilter configuration (idFormat which is set to '$1' points that ID of the checks is in the first group of commentFormat regular expressions): 

<module name="Checker">
  <module name="TreeWalker">
    <module name="SuppressWithNearbyCommentFilter">
      <property name="commentFormat"
        value="@cs\.suppress \[(\w+(\|\w+)*)\] \w[-\.'`,:;\w ]{14,}"/>
      <property name="checkFormat" value="$1"/>
      <property name="influenceFormat" value="1"/>
    </module>
    <module name="RegexpSinglelineJava">
      <property name="id" value="ignore"/>
      <property name="format" value="^.*@Ignore\s*$"/>
      <property name="message" value="@Ignore should have a reason."/>
    </module>

    <module name="RegexpSinglelineJava">
      <property name="id" value="systemout"/>
      <property name="format" value="^.*System\.(out|err).*$"/>
      <property name="message" value="Don't use System.out/err, use SLF4J instead."/>
    </module>
  </module>
</module>

Example:

@Ignore // @cs-: ignore (test has not been implemented yet)
@Test
public void testMethod() { }

public static void foo() {
  System.out.println("Debug info."); // @cs-: systemout (should not fail RegexpSinglelineJava)
}

Example of how to configure the check to suppress more than one checks. The influence format is specified in the second regexp group. 

<module name="Checker">
  <module name="TreeWalker">
    <module name="SuppressWithNearbyCommentFilter">
      <property name="commentFormat" value="@cs-\: ([\w\|]+) influence (\d+)"/>
      <property name="checkFormat" value="$1"/>
      <property name="influenceFormat" value="$2"/>
    </module>
  </module>
</module>

Example:

// @cs-: ClassDataAbstractionCoupling influence 2
// @cs-: MagicNumber influence 4
@Service // no violations from ClassDataAbstractionCoupling here
@Transactional
public class UserService {
  private int value = 10022; // no violations from MagicNumber here
}

Example of Usage

Package

com.puppycrawl.tools.checkstyle.filters

Parent Module

TreeWalker