Question

我想为一个类扩展SwingWorker，但我已经扩展了另一个类。我想知道在线程中是否存在某种变通方法（我们可以扩展它或实现它），这样我就可以在SwingWorker的doInBackground方法中使用。

我有一个对象列表，我需要在其上执行操作。对象是A，B，C类型。我创建了一个超类S，A，B，C是该超类的子类。我有一个S的对象，并在运行时通过列表我找到列表中项目的类型，并将S类型转换为A，B或C并执行操作。如果我使用SwingWorker，我只能执行一次操作，因为Swing worker只能使用一次。我无法使A，B，C扩展SwingWorker，因为它们已经扩展了S. 所以我需要为A，B，C实现SwingWorker

我还有一个A，B，C会使用的Connection对象，我把它作为Singleton，因为我不想一次又一次地初始化。

Answer 1

以下是一个示例组合示例。

预期产出：

收到部分更新列表[工人：开始]

进展：20％......

进展：70％......

进展：100％......

收到部分更新列表[工人：醒来，工人：发送   结果

工作人员完成

Launcher完成了。

代码：

package com.stackoverflow;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.List;

import javax.swing.SwingWorker;

public class DelegatingSwingWorkerDemo {

    public static void main(String[] args) {
        new Launcher().launch();
    }
}

/**
 * Use this, to launch the worker.
 */
class DelegatingSwingWorker<I, O> extends SwingWorker<I, O> {

    SwingWorkerable<I, O> delegate;

    Publisher<O> publisher;

    public DelegatingSwingWorker(SwingWorkerable<I, O> delegate) {
        this.delegate = delegate;

        publisher = new Publisher<O>() {

            @Override
            public void publish(O... chunks) {
                DelegatingSwingWorker.this.publish(chunks);
            }

            @Override
            public void setProgress(int progress) {
                DelegatingSwingWorker.this.setProgress(progress);
            }
        };
    }

    @Override
    protected void process(List<O> chunks) {
        delegate.process(chunks);
    }

    @Override
    protected void done() {
        delegate.done();
    }

    @Override
    protected I doInBackground() throws Exception {
        return delegate.doInBackground(publisher);
    }

}

interface Publisher<O> {

    void publish(O... chunks);

    void setProgress(int progress);
}

/**
 * Make your class implement the interface.
 */
interface SwingWorkerable<I, O> {

    void process(List<O> chunks);

    I doInBackground(Publisher<O> publisher);

    void done();

}

/**
 * Let's say this is your super class:
 */

class MySuperClass {

}

/**
 * Use your super class, but implement the SwingWorkerable. Then
 * launch using a DelegatingSwingWorker
 */
class SleepingDemoSwingWorkerable
    extends MySuperClass
    implements SwingWorkerable<String, String> {

    @Override
    public void process(List<String> chunks) {
        System.out.println("Received partial update list " + chunks);
    }

    @Override
    public String doInBackground(Publisher<String> publisher) {
        publisher.publish("Worker: start");
        try {
            publisher.setProgress(0);
            Thread.sleep(200);
            publisher.setProgress(20);
            Thread.sleep(500);
            publisher.setProgress(70);
            Thread.sleep(300);
            publisher.setProgress(100);
            publisher.publish("Worker: woken up");
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        publisher.publish("Worker: sending the result");
        return "Second passed.";
    }

    @Override
    public void done() {
        System.out.println("Worker Done");
    }

}

final class ConsoleProgressListener implements PropertyChangeListener {

    @Override
    public void propertyChange(PropertyChangeEvent event) {
        switch (event.getPropertyName()) {
        case "progress":
            System.out.println("Progress: " + event.getNewValue() + "%...");
        }
    }
}

/**
 * Launch
 */
class Launcher {

    public void launch() {
        SleepingDemoSwingWorkerable workerable = new SleepingDemoSwingWorkerable();
        DelegatingSwingWorker<String, String> delegatingSwingWorker =
                new DelegatingSwingWorker<String, String>(workerable);
        delegatingSwingWorker.addPropertyChangeListener(new ConsoleProgressListener());
        delegatingSwingWorker.execute();

        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        System.out.println("Launcher done.");
    }
}

对于已经扩展任何其他类以扩展或实现SwingWorker的类的任何方式

1 个答案: