スレッドを使用してメソッドを実行する

Question

スレッドを使用してSlowFileStringifier.display()メソッドを実行する必要があります。 public void display(PrintWriter out)メソッドをSlowFileStringifierクラスに実行するProxyクラスを作成しました。

プログラムは、データフォルダ内のファイルを読み取り、出力を表示します。

プロキシdisplay(PrintWriter out)はすぐにテキストを出力する必要があります。次に、SlowFileStringifier.display()メソッドを実行するスレッドを開始する必要があります。

以下

は、私が欲しい出力されます：

以下

Reading data\anaisnin.txt 
Reading data\cree.txt 
Reading data\maewest.txt 
Reading data\marktwain.txt 
Reading data\rumi.txt 
"Whenever you find yourself on the side of the majority, it is time to pause and reflect." 
- Mark Twain 
"You only live once, but if you do it right, once is enough."- Mae West 
"If you are irritated by every rub, how will your mirror be polished?" 
- Jalaluddin Mevlana Rumi 
"There came a time when the risk to remain tight in the bud was more painful than the risk it took to blossom." 
- Anais Nin 

は私のクラスです：

以下

import java.io.PrintWriter; 

public class FileStringifierProxy implements FileStringifier{ 

    private final String fileName; 

    public FileStringifierProxy(String filename) { 
     this.fileName = filename; 
} 


    @Override 
    public void display(PrintWriter out) { 
     System.out.println("Reading "+fileName); 
     SlowFileStringifier slowfilestringifier = new SlowFileStringifier(fileName); 
     slowfilestringifier.display(out); 
    } 


    @Override 
    public String stringify() { 
     // TODO Auto-generated method stub 
     return null; 
    } 



} 

import java.io.*; 
import java.util.ArrayList; 

/** 
* Simple file reader that turns a file into a string 
*/ 
public class SlowFileStringifier implements FileStringifier { 

    /** 
    * Create a file stringifier with a file name 
    * 
    * @param filename 
    *   file name of file 
    */ 
    public SlowFileStringifier(String filename) { 
     this.fileName = filename; 
    } 

    /** 
    * Writes out the file contents to the print writer 
    * 
    * @param out 
    *   the output print writer 
    */ 
    public void display(PrintWriter out) { 
     out.println(this.stringify()); 
     out.flush(); 
    } 

    /** 
    * Returns a string with all the files contents 
    */ 
    public String stringify() { 
     FileReader f; 
     try { 
      f = new FileReader(this.fileName); 
      BufferedReader bf = new BufferedReader(f); 

      ArrayList<String> lines = new ArrayList<String>(); 
      String line = null; 
      while ((line = bf.readLine()) != null) { 
       Thread.sleep(2000); 
       lines.add(line); 
      } 
      bf.close(); 
      return String.join("\n", lines); 

     } catch (FileNotFoundException e) { 
      e.printStackTrace(); 
      System.err.println("File " + this.fileName + " was not found."); 
     } catch (IOException e) { 
      e.printStackTrace(); 
      System.err.println("Problem reading file " + this.fileName + "."); 
     } catch (InterruptedException e) { 
      e.printStackTrace(); 
      System.err.println("File reading interrupted: " + this.fileName); 
     } 
     return ""; 
    } 

    private final String fileName; 
} 

public class ShowFileContents { 

    /** 
    * Accepts a file directory and then prints out the contents of all the 
    * files in that directory 
    * 
    * @param args 
    *   single arg with directory path 
    */ 
    public static void main(String[] args) { 
     if (args.length != 1) { 
      System.out.println("Usage: java ShowFileContents <directory>"); 
     } 

     String dirname = args[0]; 

     File dir = new File(dirname); 
     if (!dir.exists()) { 
      System.err.println(dirname + " does not exist"); 
      return; 
     } 
     if (!dir.isDirectory()) { 
      System.err.println(dirname + " is not a directory"); 
      return; 
     } 

     PrintWriter outWriter = new PrintWriter(System.out); 
     for (File file : dir.listFiles()) { 
      if (file.isDirectory()) 
       continue; 
      FileStringifier fd = new FileStringifierProxy(file.getPath()); 
      fd.display(outWriter); 
     } 
    } 

} 

は、私は今取得しています出力されます：あなたが使用することができます

Reading data\anaisnin.txt 
"There came a time when the risk to remain tight in the bud was more painful than the risk it took to blossom." 
- Anais Nin 
Reading data\cree.txt 
"When all the trees have been cut down, when all the animals have been hunted, when all the waters are polluted, when all the air is unsafe to breathe, only then will you discover you cannot eat money." 
- Cree Prophecy 
Reading data\maewest.txt 
"You only live once, but if you do it right, once is enough." 
- Mae West 
Reading data\marktwain.txt 
"Whenever you find yourself on the side of the majority, it is time to pause and reflect." 
- Mark Twain 
Reading data\rumi.txt 
"If you are irritated by every rub, how will your mirror be polished?" 
- Jalaluddin Mevlana Rumi 

Answer 1

CountDownLatch（@Xingbin Sunで提案）とCyclicBarrierです。どちらもスレッド同期の方法を提供します。 あなたの場合、スレッドは名前を書き終えるのを待ってから、コンテンツに進みます。

あなたの具体的な問題に対処するには、ここをクリックしてください。

あなたの主な方法：FileStringifierProxyの

public static void main(String[] args) { 
    if (args.length != 1) { 
     System.out.println("Usage: java ShowFileContents <directory>"); 
    } 

    String dirname = args[0]; 

    File dir = new File(dirname); 
    if (!dir.exists()) { 
     System.err.println(dirname + " does not exist"); 
     return; 
    } 
    if (!dir.isDirectory()) { 
     System.err.println(dirname + " is not a directory"); 
     return; 
    } 

    File[] files = dir.listFiles(); 
    int noOfFilesToProcess = 0; 
    for (final File file : files) { 
     if (!file.isDirectory()) { 
      noOfFilesToProcess++; 
     } 
    } 
    final CountDownLatch startSignal = new CountDownLatch(1); 
    final CountDownLatch doneSignal = new CountDownLatch(noOfFilesToProcess); 
    final PrintWriter outWriter = new PrintWriter(System.out); 
    for (final File file : files) { 
     if (file.isDirectory()) 
      continue; 
     Thread thread = new Thread() { 
      public void run() { 
       FileStringifier fd = new FileStringifierProxy(
         file.getPath(), startSignal, doneSignal); 
       fd.display(outWriter); 
      } 
     }; 
     thread.start(); 
    } 
    // Do something here 
    startSignal.countDown(); // let all threads proceed 
    // Do something here while other threads are processing 
    try { 
     doneSignal.await(); // wait for all to finish 
    } catch (InterruptedException e) { 
     e.printStackTrace(); 
    } 
    // Do something after all thread finishes 
} 

実装：

class FileStringifierProxy implements FileStringifier { 

    private final String fileName; 
    private final CountDownLatch startSignal; 
    private final CountDownLatch doneSignal; 

    public FileStringifierProxy(String filename, CountDownLatch startSignal, 
     CountDownLatch doneSignal) { 
     this.fileName = filename; 
     this.startSignal = startSignal; 
     this.doneSignal = doneSignal; 
    } 

    public void display(final PrintWriter out) { 
     System.out.println("Reading " + fileName); 
     final SlowFileStringifier slowfilestringifier = new 
SlowFileStringifier(
      fileName); 
     try { 
      startSignal.await(); // Wait for start signal from main thread 
     } catch (InterruptedException e) { 
      e.printStackTrace(); 
     } 
     slowfilestringifier.display(out); // Display file content 
     doneSignal.countDown(); // Send done signal to main thread 
    } 

    public String stringify() { 
     // TODO Auto-generated method stub 
     return null; 
    } 
}