[GitHub] [commons-lang] hendrixjoseph commented on pull request #933: Lang 1689 add optional to objectutils isempty

[GitBox <gi...@apache.org>]

hendrixjoseph commented on PR #933:
URL: https://github.com/apache/commons-lang/pull/933#issuecomment-1215620301

   I was thinking about this, and if we wanted to look at the contents of the Optional rather than the optional itself, there are three ways I've though of doing it - two recursive and two non-recursive:
   
   ## Recursive with Functional Methods:
   
   ```java
   if (object instanceof Optional<?>) {
       return ((Optional<?>) object).map(ObjectUtils::isEmpty).orElse(false);
   }
   ```
   
   ## Recursive with Non-Functional Methods:
   
   ```java
   if (object instanceof Optional<?>) {
       return ((Optional<?>) object).isPresent() && isEmpty(((Optional<?>) object).get());
   }
   ```
   
   ## Non-recursive
   
   ```java
   public static boolean isEmpty(Object object) {
       if (object instanceof Optional<?>) {
           object = ((Optional<?>) object).orElse(null);
       }
       if (object == null) {
           return true;
       }
       if (object instanceof CharSequence) {
           return ((CharSequence) object).length() == 0;
       }
       if (isArray(object)) {
           return Array.getLength(object) == 0;
       }
       if (object instanceof Collection<?>) {
           return ((Collection<?>) object).isEmpty();
       }
       if (object instanceof Map<?, ?>) {
           return ((Map<?, ?>) object).isEmpty();
       }
       return false;
   }
   ```
   
   I like the non-recursive method best, however, it does change the `Object object` parameter from final to non-final.
   
   ---
   
   Also, there is an isEmpty() method on optionals that was added in Java 11: https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/Optional.html#isEmpty()


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