Class ModifiedControlVariableCheck

All Implemented Interfaces:
Configurable, Contextualizable

public final class ModifiedControlVariableCheck extends AbstractCheck

Checks that for loop control variables are not modified inside the for block. An example is:

 for (int i = 0; i < 1; i++) {
   i++; //violation
 }
 

Rationale: If the control variable is modified inside the loop body, the program flow becomes more difficult to follow. See FOR statement specification for more details.

Such loop would be suppressed:

 for (int i = 0; i < 10;) {
   i++;
 }
 
  • Property skipEnhancedForLoopVariable - Control whether to check enhanced for-loop variable. Type is boolean. Default value is false.

To configure the check:

 <module name="ModifiedControlVariable"/>
 

By default, This Check validates Enhanced For-Loop.

Option 'skipEnhancedForLoopVariable' could be used to skip check of variable from Enhanced For Loop.

An example of how to configure the check so that it skips enhanced For Loop Variable is:

 <module name="ModifiedControlVariable">
   <property name="skipEnhancedForLoopVariable" value="true"/>
 </module>
 

Example:

 for (String line: lines) {
   line = line.trim();   // it will skip this violation
 }
 

Parent is com.puppycrawl.tools.checkstyle.TreeWalker

Violation Message Keys:

  • modified.control.variable
Since:
3.5
  • Field Details

    • MSG_KEY

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

    • ModifiedControlVariableCheck

      public ModifiedControlVariableCheck()
  • Method Details

    • setSkipEnhancedForLoopVariable

      public void setSkipEnhancedForLoopVariable(boolean skipEnhancedForLoopVariable)
      Setter to control whether to check enhanced for-loop variable.
      Parameters:
      skipEnhancedForLoopVariable - whether to skip enhanced for-loop variable
    • 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:
    • 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:
    • 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:
    • 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
    • visitToken

      public void visitToken(DetailAST ast)
      Description copied from class: AbstractCheck
      Called to process a token.
      Overrides:
      visitToken in class AbstractCheck
      Parameters:
      ast - the token to process
    • 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