code: public static void checkMinimumArrayLength(String parameterName,
              int actualLength, int minimumLength) {
          if (actualLength < minimumLength) {
              throw Exceptions
                      .IllegalArgument(
                              "Array %s should have at least %d elements, but it only has %d",
                              parameterName, minimumLength, actualLength);
          }
      }
docs: Check that the parameter array has at least as many elements as it
  should.
  
  @param parameterName
  The name of the user-supplied parameter that we are validating
  so that the user can easily find the error in their code.
  @param actualLength
  The actual array length
  @param minimumLength
  The minimum array length