tasks_stop和tasks_shutdown

tasks_stop和tasks_shutdown是两个函数，用于停止正在运行的任务。tasks_stop会等待任务完成当前的操作后再停止，而tasks_shutdown会立即停止任务，可能会导致任务未完成的操作失败。这两个函数在多任务操作中非常有用。

相关问题

An Executor that provides methods to manage termination and methods that can produce a Future for tracking progress of one or more asynchronous tasks. An ExecutorService can be shut down, which will cause it to reject new tasks. Two different methods are provided for shutting down an ExecutorService. The shutdown method will allow previously submitted tasks to execute before terminating, while the shutdownNow method prevents waiting tasks from starting and attempts to stop currently executing tasks. Upon termination, an executor has no tasks actively executing, no tasks awaiting execution, and no new tasks can be submitted. An unused ExecutorService should be shut down to allow reclamation of its resources. Method submit extends base method Executor.execute(Runnable) by creating and returning a Future that can be used to cancel execution and/or wait for completion. Methods invokeAny and invokeAll perform the most commonly useful forms of bulk execution, executing a collection of tasks and then waiting for at least one, or all, to complete. (Class ExecutorCompletionService can be used to write customized variants of these methods.) The Executors class provides factory methods for the executor services provided in this package. Usage Examples Here is a sketch of a network service in which threads in a thread pool service incoming requests. It uses the preconfigured Executors.newFixedThreadPool factory method:

An ExecutorService is an Executor that provides additional methods for managing termination and tracking the progress of asynchronous tasks. It extends the base Executor interface and adds functionalities such as task submission, task cancellation, and waiting for task completion.

An ExecutorService can be shut down, which means it will stop accepting new tasks and initiate the process of terminating existing tasks. There are two methods provided for shutting down an ExecutorService:

1. `shutdown()`: This method allows previously submitted tasks to complete execution before terminating the ExecutorService. It will not interrupt already running tasks, but it will prevent new tasks from being accepted.

2. `shutdownNow()`: This method attempts to stop all actively executing tasks and prevents waiting tasks from starting. It interrupts the running tasks and may forcibly terminate them.

Once an ExecutorService is shut down, it reaches a terminated state where no tasks are actively executing, no tasks are awaiting execution, and no new tasks can be submitted. It is recommended to shut down an unused ExecutorService to release its resources.

The `submit()` method is an extended version of the base `execute(Runnable)` method in the Executor interface. It submits a task for execution and returns a Future object that can be used to track the progress of the task, cancel its execution, or wait for its completion.

The `invokeAny()` and `invokeAll()` methods are higher-level methods that execute a collection of tasks and wait for their completion. `invokeAny()` waits for at least one task to complete and returns the result of the first completed task. `invokeAll()` waits for all tasks to complete and returns a list of Future objects representing the results of all tasks.

The Executors class provides factory methods for creating different types of ExecutorService instances. For example, `Executors.newFixedThreadPool()` creates a thread pool with a fixed number of threads.

Here's an example usage of an ExecutorService with a fixed thread pool:

ExecutorService executor = Executors.newFixedThreadPool(5);

// Submit tasks for execution
executor.submit(new Task1());
executor.submit(new Task2());

// Shut down the executor when no longer needed
executor.shutdown();

In this example, a fixed thread pool with 5 threads is created using the `newFixedThreadPool()` method. Two tasks, `Task1` and `Task2`, are submitted for execution using the `submit()` method. Finally, the executor is shut down using the `shutdown()` method.

用Java编写程序，界面里有三个窗口，三个窗口一共只能输出五十次，同一个窗口输出时间间隔大于一秒，在还剩输出六次时停止输出，要求输出的每一次都要有输出的时刻和输出窗口和输出次数

好的，以下是使用Java Swing编写的程序示例：

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Date;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

public class ThreeWindowsDemo extends JFrame implements ActionListener {

    private JTextArea window1TextArea;
    private JTextArea window2TextArea;
    private JTextArea window3TextArea;

    private static final int TOTAL_OUTPUT_COUNT = 50;
    private static final int STOP_OUTPUT_COUNT = 6;
    private int currentOutputCount = 0;

    private ScheduledExecutorService executorService;

    public ThreeWindowsDemo() {
        super("Three Windows Demo");

        // Create text areas for three windows
        window1TextArea = new JTextArea();
        window2TextArea = new JTextArea();
        window3TextArea = new JTextArea();

        // Create buttons to trigger output in each window
        JButton window1Button = new JButton("Window 1");
        JButton window2Button = new JButton("Window 2");
        JButton window3Button = new JButton("Window 3");

        // Add action listeners to buttons
        window1Button.addActionListener(this);
        window2Button.addActionListener(this);
        window3Button.addActionListener(this);

        // Create panels to hold text areas and buttons
        JPanel window1Panel = new JPanel(new BorderLayout());
        window1Panel.setBorder(BorderFactory.createTitledBorder("Window 1"));
        window1Panel.add(new JScrollPane(window1TextArea), BorderLayout.CENTER);
        window1Panel.add(window1Button, BorderLayout.SOUTH);

        JPanel window2Panel = new JPanel(new BorderLayout());
        window2Panel.setBorder(BorderFactory.createTitledBorder("Window 2"));
        window2Panel.add(new JScrollPane(window2TextArea), BorderLayout.CENTER);
        window2Panel.add(window2Button, BorderLayout.SOUTH);

        JPanel window3Panel = new JPanel(new BorderLayout());
        window3Panel.setBorder(BorderFactory.createTitledBorder("Window 3"));
        window3Panel.add(new JScrollPane(window3TextArea), BorderLayout.CENTER);
        window3Panel.add(window3Button, BorderLayout.SOUTH);

        // Add panels to main frame
        JPanel mainPanel = new JPanel(new GridLayout(1, 3));
        mainPanel.add(window1Panel);
        mainPanel.add(window2Panel);
        mainPanel.add(window3Panel);

        getContentPane().add(mainPanel);

        // Set up executor service to run output tasks
        executorService = Executors.newScheduledThreadPool(3);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        currentOutputCount++;

        // Check if we have reached the total output count
        if (currentOutputCount > TOTAL_OUTPUT_COUNT) {
            // Stop executor service
            executorService.shutdown();
            return;
        }

        // Get current time
        Date currentTime = new Date();

        // Determine which window triggered the output
        JTextArea textArea = null;
        if (e.getActionCommand().equals("Window 1")) {
            textArea = window1TextArea;
        } else if (e.getActionCommand().equals("Window 2")) {
            textArea = window2TextArea;
        } else if (e.getActionCommand().equals("Window 3")) {
            textArea = window3TextArea;
        }

        // Schedule output task with executor service
        executorService.schedule(new OutputTask(textArea, currentTime, currentOutputCount), 0, TimeUnit.MILLISECONDS);
    }

    private class OutputTask implements Runnable {

        private JTextArea textArea;
        private Date outputTime;
        private int outputCount;

        public OutputTask(JTextArea textArea, Date outputTime, int outputCount) {
            this.textArea = textArea;
            this.outputTime = outputTime;
            this.outputCount = outputCount;
        }

        @Override
        public void run() {
            // Check if we have reached the stop output count for this window
            if (outputCount > TOTAL_OUTPUT_COUNT - STOP_OUTPUT_COUNT) {
                return;
            }

            // Output to text area
            textArea.append(outputTime + " - Output " + outputCount + "\n");

            // Schedule next output task with executor service
            executorService.schedule(new OutputTask(textArea, new Date(), outputCount + 1), 1000, TimeUnit.MILLISECONDS);
        }
    }

    public static void main(String[] args) {
        ThreeWindowsDemo demo = new ThreeWindowsDemo();
        demo.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        demo.pack();
        demo.setVisible(true);
    }
}

这个程序创建了三个文本区域和三个按钮，点击按钮可以在相应的文本区域中输出时间、窗口和输出次数。程序使用了Java的ScheduledExecutorService来调度每次输出任务，并且在输出次数达到一定阈值时停止输出。