code: /*
  LambdaParameterName
  format = ^(id)|([a-z][a-z0-9][a-zA-Z0-9]+)$
  
  
  */
  
  package com.puppycrawl.tools.checkstyle.checks.naming.lambdaparametername;
  
  import java.util.function.BiFunction;
  import java.util.function.Function;
  
  public class InputLambdaParameterName {
  
      Function<String, String> badNamedParameterWithoutParenthesis = s -> // violation
              s.trim().toLowerCase();
  
      Function<String, String> badNamedParameterWithParenthesis = (st) -> // violation
              st.trim().toLowerCase();
  
      BiFunction<String, String, String> twoBadNamedParameters = (s1, // violation
                                                                  s2) -> s1 + s2; // violation
  
      BiFunction<String, String, String> badNamedParameterInBiFunction =
              (first, s) -> first + s; // violation
  
      Function<String, Integer> goodNamedParameterWithoutParenthesis =
              notTrimmedString -> notTrimmedString.trim().length();
  
      Function<String, Integer> goodNamedParameterWithParenthesis =
              (notTrimmedString) -> notTrimmedString.trim().length();
  
      BiFunction<String, String, Integer> goodNamedParameters =
              (first, second) -> (first + second).length();
  
  }
  