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remove is not supported for LazyList? #906
Description
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();
}
Activity
XilinJia commentedon Aug 28, 2020
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 commentedon Aug 31, 2020
LazyListis an unmodifiable list. See the class documentation. https://objectbox.io/docfiles/java/current/io/objectbox/query/LazyList.htmlEntities can be removed using their
Boxby 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 andBox.put(entity),Box.getAll(), modify some of them, andBox.put(entities)them.Note: Please ask usage questions on Stack Overflow.
https://stackoverflow.com/questions/tagged/objectbox
XilinJia commentedon Aug 31, 2020
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 commentedon Aug 31, 2020
No need to unload; findLazy() - unlike findLazyCached() - should not hold on to previously fetched objects.
XilinJia commentedon Aug 31, 2020
When I do myLazyList.get(0), don't I get the record loaded?
greenrobot commentedon Aug 31, 2020
You do. And LazyList does not keep a reference.
greenrobot-team commentedon Sep 15, 2020
Updated JavaDoc in Query and LazyList will be available with the next update.