What is a SwingWorker in Java?

SwingWorker is an abstract class developed for Swing library of the Java programming language. It is used to performed lengthy GUI interaction tasks in a background thread. While developing applications, sometimes the GUI hangs when it is trying to do some huge or lengthy task.

When to use SwingWorker Java?

2 Answers. Generally, SwingWorker is used to perform long-running tasks in Swing. Running long-running tasks on the Event Dispatch Thread (EDT) can cause the GUI to lock up, so one of the things which were done is to use SwingUtilities.

How do you use SwingUtilities?

An invokeLater() method is a static method of the SwingUtilities class and it can be used to perform a task asynchronously in the AWT Event dispatcher thread. The SwingUtilities. invokeLater() method works like SwingUtilities. invokeAndWait() except that it puts the request on the event queue and returns immediately.

How do I stop being a SwingWorker?

To cancel a running background task, invoke SwingWorker. cancel The task must cooperate with its own cancellation. There are two ways it can do this: By terminating when it receives an interrupt.

What is event dispatcher thread EDT in swing?

The event dispatching thread (EDT) is a background thread used in Java to process events from the Abstract Window Toolkit (AWT) graphical user interface event queue.

What is the use of SwingUtilities invokeLater?

Invokelater is used by java swing developer to update or perform any task on Event dispatcher thread asynchronously. invokeLater has been added into Java API from swing extension and it belongs to SwingUtilities class.

What is SwingUtilities?

SwingUtilities class has two useful function to help with GUI rendering task: 1) invokeLater(Runnable):Causes doRun. run() to be executed asynchronously on the AWT event dispatching thread(EDT). This will happen after all pending AWT events have been processed, as is described above.

How do you end a task in Java?

Task Cancellation in Java

Overview. In Java, there is no safe way to preemptively stop a task running on a Thread in that the task must cooperate and be responsive to the cancellation requests.
Use Cancellation Flag.
Use Task-Private Cancellation Flag.
Use Thread Interruption.
Summary.

What is event dispatcher?

Dispatcher – A Dispatcher is a service object that is given an Event object by an Emitter. The Dispatcher is responsible for ensuring that the Event is passed to all relevant Listeners, but MUST defer determining the responsible listeners to a Listener Provider.

What is the difference between InvokeAndWait and InvokeLater?

1) InvokeLater is used to perform a task asynchronously in AWT Event dispatcher thread while InvokeAndWait is used to perform task synchronously. 2) InvokeLater is a non-blocking call while InvokeAndWait will block until the task is completed.

What is EventQueue invokeLater?

invokeLater. public static void invokeLater(Runnable runnable) Causes runnable to have its run method called in the dispatch thread of the system EventQueue . This will happen after all pending events are processed.

What is SwingUtilities InvokeAndWait?

It is started as soon as a Swing top-level component is displayed, and it’s bascially a worker thread that has a FIFO queue of event objects that it executes one after another. And now for the finish: invokeAndWait() places the Runnable you pass to it into the EDT event queue and waits until the EDT has executed it.

What is the importance of a SwingWorker class in Java?

A SwingWorker class enables us to perform an asynchronous task in a worker thread (such as a long-running task) then update Swing components from the Event Dispatch Thread (EDT) based on the task results. It was introduced in Java 1.6 Version. The java.swing.SwingWorker class is a task worker, which performs time-consuming tasks in the background.

How many threads does SwingWorker in Java have?

For such purposes, swingworker is developed which schedules the execution of this lengthy task on a different thread while the GUI still remains responsive. Java language has three threads, namely:

How is an abstract class used in SwingWorker?

An abstract class to perform lengthy GUI-interaction tasks in a background thread. Several background threads can be used to execute such tasks. However, the exact strategy of choosing a thread for any particular SwingWorker is unspecified and should not be relied on.

What is the life cycle of a SwingWorker?

There are three threads involved in the life cycle of a SwingWorker: Current thread: The execute () method is called on this thread. It schedules SwingWorker for the execution on a worker thread and returns immediately. One can wait for the SwingWorker to complete using the get methods.