JavaFX版本的ExecutorService [英] JavaFX version of ExecutorService
问题描述
我创建了一个Java实用程序，在x内部的x花式zip文件（twx）中搜索XML。
I made a Java utility that searches inside XML inside x number of fancy zip files (twx).
最初这是一个命令行实用程序并且没有执行任何线程。
Originally this was a command line utility and did no Threading.
当我将其移动到使用JavaFX时，我遇到了冻结问题，然后将所有搜索移动到一个Task对象中进行修复。
When I moved it to use JavaFX, I ran into freeze issues and then moved all the searches into a Task object to fix.
我需要一些方法来跟踪进度，所以我实现了Progress属性和ProgressBar来跟踪。
I needed some way to track progress, so I implemented the Progress Property and the ProgressBar to track.
它工作得很好，但由于我已经是多线程，为什么不为每个Zip搜索创建一个线程。遗憾的是，这种方法效果不佳。
It worked great, but since I'm already multithreading, why not create a thread for each Zip Search. That unfortunately had not worked so well.
为了跟踪我创建一个任务数组，然后创建一个处理它们的主任务。我使用处理所有更新的进度和总属性。
To keep track I create an Array of Tasks and then a Main Task that handles them. I use a progress and total properties that handles all the updates.
这是代码
public class TextSearch {
final private SimpleDoubleProperty progress = new SimpleDoubleProperty();
final private SimpleDoubleProperty total = new SimpleDoubleProperty();
/**
*
* Kicks off a search. Creates a Task/Thread for each twx search.
* @return A task object that maintains all of the twx searches.
*
* @throws ZipException If the zip file is unreadable.
* @throws IOException If the file is unreadable.
* @throws JDOMException If the xml in the files are unreadable.
* @throws InvalidTWXFile If the twx is corrupt.
*/
public Task<?> executeSearch() throws ZipException, IOException, JDOMException, InvalidTWXFile {
//Loop through all registered twx files.
Iterator<TWExport> rit = registered.iterator();
Integer t = 0;
//Create a task for each search
final ArrayList<Task<?>> tasks = new ArrayList<Task<?>>();
while(rit.hasNext())
{
final TWExport twx = rit.next();
//Only run search if user selects to search it.
if(twx.getSearchEnabled())
{
Task<Void> task = new Task<Void>() {
@Override public Void call() {
informUser("Searching " + twx);
SearchResults proj = new SearchResults(twx);
searchResult.add(proj);
searchTwx(proj,twx);
twx.setResultCount(proj.getTotalCount());
informUser("Finished Searching " + twx);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
if (isCancelled()) {
updateMessage("Cancelled");
}
}
return null;
}
};
tasks.add(task);
t += twx.getObjects().size();
} else
{
informUser("Skipping " + twx);
}
}
total.setValue(t);
//Create the main thread that will hold all individual searches.
Task<Void> main = new Task<Void>() {
@Override
protected Void call() throws Exception {
startTime = new Date();
Iterator<Task<?>> it = tasks.iterator();
while(it.hasNext())
{
Thread t = new Thread(it.next());
t.start();
}
//Sometimes I get a hung thread in this loop
while(!progress.getValue().equals(total.getValue()))
{
updateProgress(progress.getValue(), total.getValue());
Thread.sleep(5000);
}
setEndTime(new Date());
return null;
}
};
new Thread(main).start();
return main;
}
/**
* Search through a twx file and add results to the project search results
* @param proj The parent SearchResults
* @param twx The TWExport to search
*/
private void searchTwx(SearchResults proj, TWExport twx) {
Iterator<TWObject> it = twx.getObjects().iterator();
//Iterate through the files and get the result
while(it.hasNext())
{
TWObject object = it.next();
progress.setValue(progress.getValue() + 1);
if(searchArtifacts.matcher(object.getName()).find())
{
SearchResults result = object.searchContents(searchStr);
if(result != null)
{
proj.add(result);
}
}
}
}
使用一个主线程看起来非常笨重，有时它会在一次搜索10个以上的zip文件时挂在那个循环中。
Using a main thread seems very clunky and sometimes it gets hung in that loop when searching 10+ zip files at a time.
有没有更好的方法来做到这一点，未知数量的任务？有没有类似JavaFX ExecutorService的地方，我可以在其中添加一堆任务，启动它并监控progressProperty？
Is there a better way to do this, with an unknown number of Tasks? Is there anything like a JavaFX ExecutorService where I can add a bunch of Tasks, kick it off and monitor the progressProperty?
推荐答案
这里有不需要特定于JavaFX的执行器服务：常规的 java.util.concurrent.ExecutorService 工作得很好，因为任务是 FutureTask 的子类。
There's no need for a JavaFX-specific executor service: the regular java.util.concurrent.ExecutorService works just fine, as Task is a subclass of FutureTask.
获得任务列表后，您可以将整体进度计算为每个人的进步的功能。例如，它可能只是所有进度的总和除以任务数。如果每个任务都有不同数量的项目要处理，您可能会做一些更复杂的事情。
Once you have a list of tasks, you can compute the overall progress as a function of the progress of each of them. For example, it might just be the sum of the progress of all, divided by the number of tasks. If each task has a different number of items to process, you might be able to do something more sophisticated.
这是一个简单的SSCCE：
Here's a simple SSCCE:
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.stream.Collectors;
import javafx.application.Application;
import javafx.beans.binding.DoubleBinding;
import javafx.beans.property.DoubleProperty;
import javafx.beans.property.IntegerProperty;
import javafx.beans.property.SimpleDoubleProperty;
import javafx.beans.property.SimpleIntegerProperty;
import javafx.concurrent.Task;
import javafx.concurrent.Worker;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.ProgressBar;
import javafx.scene.control.TextArea;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.Priority;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
public class MultipleTaskTest extends Application {
private final ExecutorService exec = Executors.newFixedThreadPool(5, r -> {
Thread t = new Thread(r);
t.setDaemon(true);
return t ;
});
private final Random rng = new Random();
@Override
public void start(Stage primaryStage) {
Label pendingTasksLabel = new Label();
Button button = new Button("Launch tasks");
TextArea log = new TextArea();
DoubleProperty progress = new SimpleDoubleProperty(1);
ProgressBar progressBar = new ProgressBar();
progressBar.progressProperty().bind(progress);
IntegerProperty pendingTasks = new SimpleIntegerProperty(0);
pendingTasksLabel.textProperty().bind(pendingTasks.asString("Pending Tasks: %d"));
button.disableProperty().bind(pendingTasks.greaterThan(0));
button.setOnAction(e -> {
int numTasks = rng.nextInt(5) + 4 ;
List<Task<Void>> tasks = new ArrayList<>();
for (int i = 0; i < numTasks; i++) {
tasks.add(createRandomTask());
}
// rebind progress:
progress.unbind();
progress.bind( new DoubleBinding() {
{
for (Task<Void> task : tasks) {
bind(task.progressProperty());
}
}
@Override
public double computeValue() {
return tasks.stream().collect(Collectors.summingDouble(
task -> Math.max(task.getProgress(), 0)
)) / numTasks;
}
});
log.appendText("Submitting "+numTasks+" tasks\n");
pendingTasks.set(numTasks);
// log state of each task:
tasks.forEach(task ->
task.stateProperty().addListener((obs, oldState, newState) -> {
log.appendText("\tTask "+newState+"\n");
// update pendingTasks if task moves out of running state:
if (oldState == Worker.State.RUNNING) {
pendingTasks.set(pendingTasks.get() - 1);
}
}));
tasks.forEach(exec::execute);
});
VBox root = new VBox(10, pendingTasksLabel, progressBar, log, button);
root.setAlignment(Pos.CENTER);
root.setPadding(new Insets(10));
VBox.setVgrow(log, Priority.ALWAYS);
primaryStage.setScene(new Scene(root, 400, 400));
primaryStage.show();
}
@Override
public void stop() {
exec.shutdownNow() ;
}
private Task<Void> createRandomTask() {
int numSteps = 100 + rng.nextInt(100);
return new Task<Void>() {
@Override
public Void call() throws Exception {
for (int i = 1; i <= numSteps; i++) {
Thread.sleep(50);
updateProgress(i, numSteps);
}
return null ;
}
};
}
public static void main(String[] args) {
launch(args);
}
}
这篇关于JavaFX版本的ExecutorService的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
