| /* |
| * Copyright 2000-2009 JetBrains s.r.o. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package com.intellij.util.concurrency; |
| |
| import com.intellij.openapi.application.ApplicationManager; |
| import com.intellij.openapi.application.ModalityState; |
| import com.intellij.openapi.diagnostic.Logger; |
| |
| /** |
| * This is the 3rd version of SwingWorker (also known as |
| * SwingWorker 3), an abstract class that you subclass to |
| * perform GUI-related work in a dedicated thread. For |
| * instructions on using this class, see: |
| * |
| * http://java.sun.com/docs/books/tutorial/uiswing/misc/threads.html |
| * |
| * Note that the API changed slightly in the 3rd version: |
| * You must now invoke start() on the SwingWorker after |
| * creating it. |
| */ |
| public abstract class SwingWorker { |
| private static final Logger LOG = Logger.getInstance("#com.intellij.util.concurrency.SwingWorker"); |
| private Object value; |
| // see getValue(), setValue() |
| |
| private final ModalityState myModalityState; |
| |
| /** |
| * Class to maintain reference to current worker thread |
| * under separate synchronization control. |
| */ |
| private static class ThreadVar { |
| private Thread myThread; |
| |
| ThreadVar(Thread t) { |
| myThread = t; |
| } |
| |
| synchronized Thread get() { |
| return myThread; |
| } |
| |
| synchronized void clear() { |
| myThread = null; |
| } |
| } |
| |
| private final ThreadVar myThreadVar; |
| /** |
| * Get the value produced by the worker thread, or null if it |
| * hasn't been constructed yet. |
| */ |
| |
| protected synchronized Object getValue() { |
| return value; |
| } |
| |
| /** |
| * Set the value produced by worker thread |
| */ |
| |
| private synchronized void setValue(Object x) { |
| value = x; |
| } |
| |
| /** |
| * Compute the value to be returned by the <code>get</code> method. |
| */ |
| |
| public abstract Object construct(); |
| |
| /** |
| * Called on the event dispatching thread (not on the worker thread) |
| * after the <code>construct</code> method has returned. |
| */ |
| |
| public void finished() { |
| } |
| |
| /** |
| * Called in the worker thread in case a RuntimeException or Error occurred |
| * if the <code>construct</code> method has thrown an uncaught Throwable. |
| */ |
| public void onThrowable() { |
| } |
| |
| /** |
| * A new method that interrupts the worker thread. Call this method |
| * to force the worker to stop what it's doing. |
| */ |
| |
| public void interrupt() { |
| Thread t = myThreadVar.get(); |
| if (t != null){ |
| t.interrupt(); |
| } |
| myThreadVar.clear(); |
| } |
| |
| /** |
| * Return the value created by the <code>construct</code> method. |
| * Returns null if either the constructing thread or the current |
| * thread was interrupted before a value was produced. |
| * |
| * @return the value created by the <code>construct</code> method |
| */ |
| |
| public Object get() { |
| while(true){ |
| Thread t = myThreadVar.get(); |
| if (t == null){ |
| return getValue(); |
| } |
| try{ |
| t.join(); |
| } |
| catch(InterruptedException e){ |
| Thread.currentThread().interrupt(); |
| // propagate |
| return null; |
| } |
| } |
| } |
| |
| /** |
| * Start a thread that will call the <code>construct</code> method |
| * and then exit. |
| */ |
| |
| public SwingWorker() { |
| myModalityState = ModalityState.current(); |
| |
| final Runnable doFinished = new Runnable() { |
| public void run() { |
| finished(); |
| } |
| }; |
| |
| Runnable doConstruct = new Runnable() { |
| public void run() { |
| try{ |
| setValue(construct()); |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("construct() terminated"); |
| } |
| } |
| catch (Throwable e) { |
| LOG.error(e); |
| onThrowable(); |
| throw new RuntimeException(e); |
| } |
| finally{ |
| myThreadVar.clear(); |
| } |
| if (LOG.isDebugEnabled()) { |
| LOG.debug("invoking 'finished' action"); |
| } |
| ApplicationManager.getApplication().invokeLater(doFinished, myModalityState); |
| } |
| }; |
| |
| final Thread workerThread = new Thread(doConstruct, "SwingWorker work thread"); |
| workerThread.setPriority(Thread.NORM_PRIORITY); |
| myThreadVar = new ThreadVar(workerThread); |
| } |
| |
| /** |
| * Start the worker thread. |
| */ |
| |
| public void start() { |
| Thread t = myThreadVar.get(); |
| if (t != null){ |
| t.start(); |
| } |
| } |
| } |