Question

In clojure you can create a SwingWorker proxy and implement doInBackground and do methods. How would you go on to invoke execute method of swingworker?

Answer 1

You can create and invoke a SwingWorker using standard Java interop, e.g.:

;; define a proxy that extends SwingWorker
(def my-swing-worker 
  (proxy [SwingWorker] []
    (doInBackground []
      (reduce + (range 1000000)))))

;; run the SwingWorker
(.execute my-swing-worker)

;; Get the result
(.get my-swing-worker)
=> 499999500000

However, normally in Clojure you wouldn’t use SwingWorkers directly. There is already a feature in Clojure that provides the functionaility of a SwingWorker: a future uses a separate thread to calculate a long running task and allows you to get the result later. Example usage:

;; define and launch a future
(def my-future 
  (future 
    (reduce + (range 1000000))))

;; get the result (will wait for future to complete if needed)
@my-future
=> 499999500000

I think most people would agree the “pure Clojure” way is simpler and more idiomatic for running background tasks. The only reason I can think of to prefer SwingWorker is if you are using some of the specific GUI integration features it provides (e.g. the ability to fire property change events).