Jun 19 2019

V6067. Two or more case-branches perform the same actions.

Jun 19 2019

The analyzer has detected that multiple case clauses of the switch statement contain the same code. It may often indicate redundant code and can be improved by merging the labels. Identical code fragments may also be copy-pasting errors.

The example of a redundant code:

public static String getSymmetricCipherName(SymmetricKeyAlgorithmTags tag)
{
    switch (tag)
    {
        case DES:
            return "DES";
        case AES_128:
            return "AES";
        case AES_192:
            return "AES";
        case AES_256:
            return "AES";
        case CAMELLIA_128:
            return "Camellia";
        case CAMELLIA_192:
            return "Camellia";
        case CAMELLIA_256:
            return "Camellia";
        case TWOFISH:
            return "Twofish";
        default:
            throw new IllegalArgumentException("....");
    }
}

The case labels may trigger the same actions, so the code can be simplified. In real projects there are cases when it is needed to perform equal actions. In order to make the code more readable, one can write the code more densely:

public static String getSymmetricCipherName(SymmetricKeyAlgorithmTags tag)
{
    switch (tag)
    {
        case DES:
            return "DES";
        case AES_128:
        case AES_192:
        case AES_256:
            return "AES";
        case CAMELLIA_128:
        case CAMELLIA_192:
        case CAMELLIA_256:
            return "Camellia";
        case TWOFISH:
            return "Twofish";
        default:
            throw new IllegalArgumentException("....");
    }
}

The next example, taken from a real application, demonstrates a typo resulting in an error:

protected boolean condition(Actor actor) throws ....
{
  ....
  if (fieldValue instanceof Number) 
  {
    ....
    switch (tokens[2]) 
    {
      case "=":
      case "==":
        passing = (Double) fieldValue
                  == 
                  Double.parseDouble(secondValue);
        break;
      case "!":
      case "!=":
        passing = (Double) fieldValue 
                  ==
                  Double.parseDouble(secondValue);
        break;
      case "<=":
        passing = ((Number) fieldValue).doubleValue() 
                  <=
                  Double.parseDouble(secondValue);
        break;
      ....
    }
   ....
  }
  ....
}

There is a typo in the code of the ! and != labels which apparently occurred due to copy-pasting. After viewing other case branches, we can conclude that the comparison operator != should be used instead of ==.

The fixed code:

protected boolean condition(Actor actor) throws ....
{
  ....
  if (fieldValue instanceof Number) 
  {
    ....
    switch (tokens[2]) 
    {
      case "=":
      case "==":
        passing = (Double) fieldValue
                  ==
                  Double.parseDouble(secondValue);
        break;
      case "!":
      case "!=":
        passing = (Double) fieldValue 
                  !=
                  Double.parseDouble(secondValue);
        break;
      case "<=":
        passing = ((Number) fieldValue).doubleValue() 
                  <=
                  Double.parseDouble(secondValue);
        break;
      ....
    }
   ....
  }
  ....
}

This diagnostic is classified as: