remove is not supported for LazyList?

[XilinJia]

Basic info (please complete the following information):

• ObjectBox version (are you using the latest version?): [e.g. 2.7.0]
• Reproducibility: [always]
• Device: [e.g. Lenovo K5]
• OS: [e.g. Android 6]

To Reproduce
Steps to reproduce the behavior:

List<Word> sList = wordBox.query().build().findLazy();
Word w = sList.get(0);
// do something
sList.remove(0);

Got an exception.

Had a peek in LazyList.java:

    @Override
    public E remove(int location) {
        throw new UnsupportedOperationException();
    }

[XilinJia]

I need to update all records in an entity based on new information. The purpose I use LazyList and do the get and remove is to avoid loading my entire query. Now remove doesn't work, how can I avoid loading the entire entity?

[greenrobot-team]

LazyList is an unmodifiable list. See the class documentation. https://objectbox.io/docfiles/java/current/io/objectbox/query/LazyList.html

Entities can be removed using their Box by passing their ID or their instance.
https://docs.objectbox.io/getting-started#basic-box-operations

Edit: ok, maybe I misunderstood. Some other options:

• Box.get(id) the entities and Box.put(entity),
• just get all of them Box.getAll(), modify some of them, and Box.put(entities) them.

Note: Please ask usage questions on Stack Overflow.
https://stackoverflow.com/questions/tagged/objectbox

[XilinJia]

Thank you for responding.

The main point I want to understand is how to work with items one by one on the lazylist without having to load all the list items into memory at the same time. I was hoping to load one by get(0), work with it, then unload it with remove(0), then load in the next one. Now I understand that LazyList is unmodifiable, so I can't remove(0), is there a way to unload the record I loaded before loading in the next record?

[greenrobot]

No need to unload; findLazy() - unlike findLazyCached() - should not hold on to previously fetched objects.

• @greenrobot-team I think we could improve our JavaDocs here a bit.

[XilinJia]

When I do myLazyList.get(0), don't I get the record loaded?

[greenrobot]

You do. And LazyList does not keep a reference.

[greenrobot-team]

Updated JavaDoc in Query and LazyList will be available with the next update.