gwt延迟调度调试

Question

How can one efficiently debug a component that extensively uses the scheduleDeferred/scheduleFinally calls? For some reason some calls get swallowed and don't get executed. One option in mind is try to simplify the scenario until reaching a minimal number of interactions. But even then, it's not easy to see why the calls get swallowed by the browser.

Answer 1

If an exception occurs inside a callback/deferred method, it might just get swallowed and will not execute the next deferred call. Sometimes you will see a JavaScript exception, but I already saw code where no exception was shown at all and just execution of this deferred call was stopped - pretty hard to find the cause.

I am just assuming you are using Super Dev Mode or running in production mode (compiled release) here, because in normal dev mode GWT should catch exceptions.

To protect against this, surround the content of every deferred call with a try/catch and either log or show a message if an exception occurs. That even will show an error if your breakpoint gets not triggered correctly.