Remove elements from List of objects by comparing with another array in Java

Question

I have a list of subscriptions

subscriptions = [
      { 
        code : "Heloo",
        value:"some value",
        reason : "some reason"
      },
      { 
        code : "Byeee",
        value:"some byee",
        reason : "some byee"
      },
      { 
        code : "World",
        value:"some World",
        reason : "some world"
      }
    ]

I have another list of unsubscriptions:

unsubscribe : ["Heloo","World"]

I want to unsubscribe elements in the subscriptions by comparing these two arrays

Final Result :

subscriptions = [
  { 
    code : "Byeee",
    value:"some byee value",
    reason : "some byee reason"
  }
]

Below is my solution :

List<String> newList = new ArrayList<>();
for (String products : subscriptions) {
        newList.add(products.code);
 }

if (!newList.containsAll(unsubscribe) {
        log.error("Few products are not subscribed");  
}

for (int i = 0; i < subscriptions.size(); i++) {
        if(unsubscribe.contains(subscriptions.get(i).code)) {
          subscriptions.remove(i);
        }
}

This could be better . I am looking for a better/optimized solution.

Answer 1

Using removeIf will clean up your code considerably:

List<Subscription> subscriptions =  ... ;
List<String> unsubscribe = ...;

subscriptions.removeIf(s -> unsubscribe.contains(s.code));

Answer 2

You can also do it with streams:

List<String> newList = subscriptions
                                 .stream()
                                 .filter(it -> !unsubscribe.contains(it.code))
                                 .collect(Collectors.toList());