react4j.internal.SchedulerUtil Maven / Gradle / Ivy
The newest version!
package react4j.internal;
import arez.Arez;
import arez.Disposable;
import arez.annotations.ArezComponent;
import javax.annotation.Nullable;
import zemeckis.Zemeckis;
/**
* Utilities for interacting with the Arez scheduler.
*/
public final class SchedulerUtil
{
/**
* A non-null lock that will be released in the next micro-task which will schedule any renders required.
*/
@Nullable
private static Disposable c_schedulerLock;
private SchedulerUtil()
{
}
/**
* The first time an react4j view is rendered it will lock the Arez scheduler and release
* the lock in the micro-task immediately following the task that prompted the render. If this
* is not done it is possible that Arez can re-trigger a view render when the scheduler is
* triggered after the tracked render completes but before the render method has returned to the
* react runtime. This results in error message from react as a setState()/forceRender() was invoked
* while still within a render() method.
*
* NOTE: While render methods are read-only transactions, they can un-observe components with
* {@link ArezComponent#disposeOnDeactivate()} set to true that would result in the
* arez component being disposed and triggering an update that would mark particular React
* view/Observers as STALE and trigger a re-render of that view.
*/
public static void pauseUntilRenderLoopComplete()
{
if ( null == c_schedulerLock )
{
c_schedulerLock = Arez.context().pauseScheduler();
// schedule immediately after this call stack pops.
Zemeckis.microTask( () -> {
c_schedulerLock.dispose();
c_schedulerLock = null;
} );
}
}
}