JDK-8353755 : Add a helper method to Util - findComponent()

[honkar-jdk]

findComponent(final Container container, final Predicate<Component> predicate) is a useful utility method and thus added to javax/swing/regtesthelpers/Util.java instead of having redundant code in tests. It can be used to find a component by label name.

PS: Existing Util.findSubComponent() finds component by class name but findComponent() can be used to search for a particular component by label name/title when there are multiple subcomponents of same type by applying a predicate logic.

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• JDK-8353755: Add a helper method to Util - findComponent() (Enhancement - P4)

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[mlbridge]

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[aivanov-jdk]

The documentation could then explain the parameters, don't you think?

Always run this method on the EDT thread

The utility method could ensure this automatically. This public method will be a wrapper around a private implementation, the implementation will run directly or on EDT using invokeOnEDT which already exists in the Util class.

[honkar-jdk]

There are some tests where EDT calls are interleaved between calls to robot (non-EDT) (e.g bug4759934.java - findCancelButton()) and few other tests (e.g FileSizeCheck.java - findDetailsButton() and findTable() that are within upper level method which is called on EDT). Is it better to leave it as-is for flexibility rather than add a wrapper?

If a wrapper is added we might need to check if it is already on EDT thread or not as below:

if (isEventDispatchThread()) {
   return _findComponent(container, predicate);
} else {
  return Util.invokeOnEDT(() -> _findComponent(container, predicate));
}

[aivanov-jdk]

If a wrapper is added we might need to check if it is already on EDT thread or not as below:

This is what I said: “the implementation will run directly or on EDT.” So if it's already on EDT, call directly; it it's not, use invokeOnEDT.

The utility method can then be used in all the contexts without thinking. (The implementation, if you choose this way, should rather be findComponentImpl rather than prefixed with an underscore.)

Likely, one still needs to call findComponent on EDT because any other operations on the component need to be on EDT. In this case, findComponent could throw an exception if it's called not on EDT.

These things will ensure the method can work correctly.

[aivanov-jdk]

Existing Util.findSubComponent() finds component by class name

To eliminate code duplication, the existing findSubComponent should use the new findComponent which is more flexible. Just pass parent.getClass().getName().contains(className) as the predicate to the new method.

[aivanov-jdk]

doClick should also be called on EDT.

[aivanov-jdk]

In this case, I would leave the wrapped predicate parameter as is; otherwise, the lines become too long. This is why I chose to use the 8-column indentation for the second parameter rather than aligning it with the opening parenthesis.