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Synchronous InfiniteContainer

Synchronous InfiniteContainer

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InfiniteContainer and
revolutionized the way we think about Codename One. Up until their introduction we advocated lists for large
sets of components and this is no longer the case.

However, InfiniteContainer has a controversial feature even within out team. It violates the EDT on purpose…​

InfiniteContainer allows you to “fetch” data dynamically into the container as the user scrolls down. The definition
of “fetch” is problematic though. Up until now the fetch
method was invoked in a separate thread. This was documented in the class but it is pretty problematic as the
method returns an array of components.

In practice creating a component in a separate shouldn’t pose a problem, yes it does violate the core Codename One
principal of always doing everything on the EDT but construction should work. However, this does include some

  • The EDT violation detection marks such code as violating

  • The most common case (networking) already works rather well off the EDT and doesn’t need a separate thread

  • This is inconsistent with the rest of Codename One

  • There are some edge cases where this might trigger a real EDT violation e.g. if component construction triggers
    an event thus creating a race condition with the EDT

So to workaround this we added the new method: protected boolean isAsync().

If you override this method to return false the fetch method will be invoked on the EDT but this might break
compatibility so currently this method is set to return true.

We currently plan to change the method to return false by default within a couple of weeks. This might change
based on feedback we get from developers.