【发布时间】：2014-06-18 09:50:36
【问题描述】：
大家好（第一篇）！
首先让我说我对 Java 编程还是比较陌生（C++ 是我的强项）
如果这个问题已经得到解答，请指出我正确的方向，但我的搜索技能还没有产生我正在寻找的东西。我遇到的问题是在我的消费者线程之间同步，而不是在我的生产者/消费者之间同步
我的任务是从生产者线程中寻找素数候选者，而不是使用多个消费者线程来检查每个候选者的有效性：
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使用多个线程，1 个生产者线程将“候选人”放入名为 prime_candidates 的数组列表（必须是数组列表）中，消费者从数组列表中抓取并检查
消费者检查是否是素数，然后将素数放入自己的arraylist prime_list
60 秒后 prime_list 被写入文件并继续
我已成功将 prime_candidates 与消费者（检查）线程同步。但是我一辈子都无法弄清楚如何同步消费者线程产生的 ArrayLists。他们都自己制作，并且使用我从生产者/消费者那里使用的同步方法不起作用。
生产者线程
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Date;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class GenerateThread implements Runnable{
// MAIN ARRAY LIST THAT STORES THE NUMBERS WHICH COULD BE CONSIDERED PRIME CANDIDATES
private final ArrayList<PrimeCandidate> prime_candidates = new ArrayList();
private boolean alive = true; // MAIN VARIABLE THAT WILL CONTINUE TO RUN THE THREAD
private boolean toggle = true; // VARIABLE THAT PAUSES THE PRODUCER
// START: FOR PANEL LAYOUT //
JPanel genPanel = new JPanel();
JPanel lastPane = new JPanel();
JLabel lastOutput = new JLabel();
JPanel queuePane = new JPanel();
JLabel queueOutput = new JLabel();
JLabel headLabel = new JLabel("Generate Thread");
JLabel lastLabel = new JLabel("Last");
JLabel queueLabel = new JLabel("Queue");
JButton pauseButton = new JButton("Pause");
JButton terminateButton = new JButton("Terminate");
// END: FOR PANEL LAYOUT //
// DEFAULT CONSTRUCTOR, DOESN'T REALLY DO MUCH
GenerateThread(){ System.out.println("Creating Generator");}
public JPanel createPanel()
{
// TO SET THE BLACK BORDER AROUND THE PANELS HOLDING CURRENT SIZE AND
// PRIME CANDIDATE
lastPane.setBorder(BorderFactory.createLineBorder(Color.black));
queuePane.setBorder(BorderFactory.createLineBorder(Color.black));
// ADD LISTENER TO TERMINATE THREAD
terminateButton.addActionListener(new terminateListener());
// ADD LISTENER TO PAUSE THREAD
pauseButton.addActionListener(new pauseListener());
lastPane.add(lastOutput);
queuePane.add(queueOutput);
genPanel.add(headLabel);
genPanel.add(lastLabel);
genPanel.add(lastPane);
genPanel.add(queueLabel);
genPanel.add(queuePane);
genPanel.add(pauseButton);
genPanel.add(terminateButton);
return genPanel;
}
@Override
public void run()
{
long i = 3;
while(alive)
{
if(toggle)
{
if(i % 2 == 1)
if(!TestForPrime.isDividableBy3(BigInteger.valueOf(i)))
{
addToArrayList(BigInteger.valueOf(i));
lastOutput.setText(BigInteger.valueOf(i).toString());
queueOutput.setText(BigInteger.valueOf(prime_candidates.size()).toString());
}
i++;
}
if(!toggle)continueNotifying();
}
while(!alive){continueNotifying();}
}
// ADDS NEW ITEM TO ARRAYLIST AND NOTIFYS ALL THREADS DEPENDENT ON ARRAYLIST
public synchronized void addToArrayList(BigInteger b)
{
prime_candidates.add(new PrimeCandidate(b, new Date()));
notify();
}
// CONTINUES NOTIFYING OTHER THREADS WHEN PAUSED OR TERMINATED SINCE THEY WILL
// NOT RUN UNLESS THEY HAVE BEEN GIVEN THE 'GO AHEAD' (NOTIFY())
public synchronized void continueNotifying()
{
queueOutput.setText(BigInteger.valueOf(prime_candidates.size()).toString());
notify();
}
// USED BY THE OTHER THREADS TO GET ITEMS FROM THE ARRAY LIST, THREADS DELETE
// THE VARIABLE THAT THEY GRAB, ESSENTIALLY CUTTING THE ARRAY LIST DOWN EVERY
// TIME
public synchronized PrimeCandidate getFromArrayList() throws InterruptedException
{
wait(); //Keeps thread from adding more to list while others are grabbing it
PrimeCandidate returnCandidate = new PrimeCandidate(prime_candidates.get(0));
prime_candidates.remove(0);
return returnCandidate;
}
// LISTENER THAT WILL KILL THE THREAD PRIME CANDIDATE PRODUCER
// ALSO GREYS OUT BOTH BUTTONS TO SHOW THREAD IS DEAD
class terminateListener implements ActionListener
{
@Override
public void actionPerformed(ActionEvent e)
{
terminateButton.setEnabled(false);
pauseButton.setEnabled(false);
alive = false;
}
}
// LISTENER THAT WILL TEMPORARILY STOP THE PRODUCER
class pauseListener implements ActionListener
{
@Override
public void actionPerformed(ActionEvent e)
{
if(toggle)
pauseButton.setText("Start");
if(!toggle)
pauseButton.setText("Pause");
toggle = !toggle;
}
}
}
消费者话题
import java.awt.Color;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Date;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;
public class CheckThread implements Runnable{
private final GenerateThread generated;
private ArrayList<Primes> prime_list = new ArrayList();
//private CopyOnWriteArrayList<Primes> prime_list = new CopyOnWriteArrayList();
private final String threadName;
private boolean alive = true;
private boolean toggle = true;
private Date timeFetched;
private Date timeFound;
private Primes currentPrime;
// START: FOR PANEL LAYOUT //
JPanel genPanel = new JPanel();
JPanel lastPane = new JPanel();
JLabel lastOutput = new JLabel();
JPanel queuePane = new JPanel();
JLabel queueOutput = new JLabel();
JLabel headLabel = new JLabel("Generate Thread");
JLabel lastLabel = new JLabel("Last");
JLabel queueLabel = new JLabel("In Work");
JButton pauseButton = new JButton("Pause");
JButton terminateButton = new JButton("Terminate");
// END: FOR PANEL LAYOUT //
CheckThread(GenerateThread gen, String name, int priority)
{
generated = gen;
threadName = name;
headLabel.setText(name);
System.out.println("Creating | " + name);
if(priority == 0)
{
System.out.println(name + " Is writing thread");
final Timer t = new Timer(10000, new writeToFileTimer());
t.start();
}
}
public JPanel createPanel()
{
lastPane.setBorder(BorderFactory.createLineBorder(Color.black));
lastPane.setMinimumSize(new Dimension(200,100));
queuePane.setBorder(BorderFactory.createLineBorder(Color.black));
terminateButton.addActionListener(new terminateListener());
pauseButton.addActionListener(new pauseListener());
lastPane.add(lastOutput);
queuePane.add(queueOutput);
genPanel.add(headLabel);
genPanel.add(lastLabel);
genPanel.add(lastPane);
genPanel.add(queueLabel);
genPanel.add(queuePane);
genPanel.add(pauseButton);
genPanel.add(terminateButton);
lastOutput.setIgnoreRepaint(true);
return genPanel;
}
class writeToFileTimer implements ActionListener
{
@Override
public void actionPerformed(ActionEvent event)
{
try{ writeToFile();}catch (InterruptedException e) { System.out.println("WTF");}
}
}
@Override
public void run()
{
while(alive)
{
try
{
if(toggle)
{
PrimeCandidate recieved = new PrimeCandidate(generated.getFromArrayList());
timeFetched = new Date();
//queueOutput.setText(recieved.getCandidate().toString());
if(TestForPrime.isPrime(recieved.getCandidate()))
{
lastOutput.setText(recieved.getCandidate().toString());
timeFound = new Date();
String temp = "" + prime_list.size();
queueOutput.setText(temp);
addToArrayList(new Primes(recieved.getCandidate(),recieved.getTimeStamp(), timeFetched));
}
}
} catch (InterruptedException e) {}
}
}
class terminateListener implements ActionListener
{
@Override
public void actionPerformed(ActionEvent e)
{
terminateButton.setEnabled(false);
pauseButton.setEnabled(false);
alive = false;
}
}
class pauseListener implements ActionListener
{
@Override
public void actionPerformed(ActionEvent e)
{
if(toggle)
pauseButton.setText("Start");
if(!toggle)
pauseButton.setText("Pause");
toggle = !toggle;
}
}
// ADDS NEW ITEM TO ARRAYLIST AND NOTIFYS ALL THREADS DEPENDENT ON ARRAYLIST
public synchronized void addToArrayList(Primes primeFound)
{
prime_list.add(primeFound);
}
// USED BY THE OTHER THREADS TO GET ITEMS FROM THE ARRAY LIST, THREADS DELETE
// THE VARIABLE THAT THEY GRAB, ESSENTIALLY CUTTING THE ARRAY LIST DOWN EVERY
// TIME
public synchronized void writeToFile() throws InterruptedException
{
wait();
try
{
File statText = new File("prime_numbers.txt");
FileOutputStream is = new FileOutputStream(statText);
OutputStreamWriter osw = new OutputStreamWriter(is);
Writer writ = new BufferedWriter(osw);
while(!prime_list.isEmpty())
{
writ.append(prime_list.get(0).toString());
prime_list.remove(0);
}
writ.close();
headLabel.setText(threadName);
} catch (IOException e) {System.err.println(" failed to write to Test.txt");}
notify();
}
}
我知道代码写得不好，但是当我做这个任务时，我一直在碰壁，从头开始重写我的代码，最终不再关心。有谁知道我如何可以轻松地在消费者线程中同步我的所有 prime_list Arraylist。如果您没有注意到我构建了每个数组列表，那么我可以简单地将每个线程/面板添加到主框架。它在获取和检查素数方面完美无缺，但我目前的头痛是将所有线程一起产生的文件写入文件。我可以将每个线程单独写入文件，但它们最终每次都相互写入
【问题讨论】：
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您的问题是什么？请用一句话。
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欢迎来到社区。我建议在阅读完此内容后编辑您的问题：msmvps.com/blogs/jon_skeet/archive/2010/08/29/…
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如果你“终于不再关心”了，为什么还要指望别人关心呢？更重要的是：您应该对问题进行表述，以便可以理解您需要帮助的内容，并且您的代码应该简短并且仅包含与您所询问的问题相关的部分 - 在您的情况下，这里不需要任何 GUI 代码.
标签： java multithreading arraylist synchronization