java - 如何使用来自单独线程的数据将文本附加到 JTextArea

Question

我有一个 Scheduler 类，其中有一个线程负责创建 Process 对象，我想在创建 Process 对象时获取它们并将有用信息显示到 JTextArea。但是，当 Scheduler 类创建 Process 时，JTextArea 保持空白。每次创建新进程时如何通知或更新 JTextArea？还有一个 ArrayBlockingQueue 存储每个 Process，直到 CPU 类执行它。

我尝试设置事件监听器来 try catch 进程创建的时间。

public class Main {

    public static void main(String[] args) {



            Scheduler scheduler = new Scheduler();
            scheduler.createProcesses();

            SwingUtilities.invokeLater(new Runnable(){

                public void run(){
                    JFrame frame = new MainFrame();
                    frame.setVisible(true);
                    frame.setSize(500,500);
                    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

                }
            });

    }
 }

Main 创建 Scheduler 对象，然后调用 createProcess()。然后它调用 SwingUtilities 可运行线程。

import java.awt.BorderLayout;
import java.awt.Container;
import java.util.Random;
import java.util.concurrent.ArrayBlockingQueue;
import java.lang.Math;
import javax.swing.JFrame;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.SwingWorker;

public class Scheduler {
    private static final int MAX_QUEUE_SIZE = 1001;
    private CPU cpu;
    private MainFrame frame;
    ArrayBlockingQueue<Process> readyQueue;
    int time = 0;
    int pid = 1000;



    public Scheduler()
    {
        readyQueue = new ArrayBlockingQueue<Process>(MAX_QUEUE_SIZE, true);
        this.cpu = new CPU(this);
        frame = new MainFrame();

        }//end of constructor


    public void createProcesses()  //populate ready queue
    {


        new Thread(new Runnable() {
            @Override
            public void run() {
                // Create 1002 processes
                Scheduler.this.cpu.start();
                while(pid < 2002) {
                    Random rand = new Random();
                    int meanRunTime = 10;
                    int sd = 2;
                    // Random number following a Normal distribution
                    int runTime = (int) Math.round(rand.nextGaussian()) * sd + meanRunTime;
                    int meanDelayTime = 5;
                    sd = 1;
                    int arrivalDelayTime = (int) Math.round(rand.nextGaussian()) * sd + meanDelayTime;
                    //System.out.println(Scheduler.this.time);
                    try {
                            // Wait for process to arrive
                            Thread.sleep(arrivalDelayTime);
                            Scheduler.this.time += arrivalDelayTime;
                        } catch (InterruptedException e) {
                            System.out.println("Queue waiting for arival interrupted");
                        }

                    Process p = new Process(Scheduler.this.pid, Process.WAITING, (time), runTime);    //constructs Process


                    System.out.println(p.toString());
                    frame.setProcess(p);   //This is where I am attempting to pass the process to the frame however this does not seem to work


                    Scheduler.this.pid++;
                    try {
                    Scheduler.this.readyQueue.put(p);
                    } catch (InterruptedException e){
                        e.printStackTrace();
                    }

                }

            }

        }).start();

    }//end of create process

这是调度程序类。基本上，当它创建 Process p 时，我需要它告诉 GUI 有关新创建的进程的信息，以便可以将其添加到 processTextArea

import java.awt.BorderLayout;
import java.awt.Container;
import java.util.concurrent.ArrayBlockingQueue;
import javax.swing.JFrame;
import javax.swing.JTextArea;
import javax.swing.JTextField;



public final class MainFrame extends JFrame{

    private Process process;





    public MainFrame(){

            //Layout of Frame
            setLayout(new BorderLayout());

            //Creation of Components that will go into the Frame
            JTextArea processTextArea = new JTextArea("Awaiting Completed Processes");

            while(process != null){
                processTextArea.setText(process.toString());
                process = null;
            }

            //Adds Compnents to the content frame
            Container c = getContentPane();
            c.add(processTextArea, BorderLayout.EAST);







    }



    public void setProcess(Process p){
        this.process = p;


    }

MainFrame 是 GUI 类。目前，Scheduler 类中进行的 setProcess 调用确实为 MainFrame 类提供了一个进程对象，但仅一次。每次创建新进程时如何更新它？

我希望在创建新进程时让 GUI 填充 processTextArea。目前发生的情况是 GUI 框架弹出，但没有任何内容添加到 processTextArea。

Answer 1

This is the scheduler class. Basically when it creates Process p i need it to tell the GUI about the newly created process so that it can be added to processTextArea

我认为Main中的MainFrame对象和Scheduler中的MainFrame是两个不同的引用？你应该先解决这个问题。

I Wish to have the GUI fill up the processTextArea as new Process's are being created. What happens at the moment is The GUI frame pops up however nothing is being added to the processTextArea.

提取processTextArea成为MainFrame的成员，并创建一个如下方法:

public void onProcessComplete(Process P) {
    synchronized (processTextArea) {
        processTextArea.append(process.toString());
    }
}

每当Process完成时，调用mainFrame.onProcessComplete(this)。这应该可以满足您的需求。