BlockingQueue

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
/*  j  a  v a  2s . co  m*/
public class Main {
  public static void main(String[] argv) throws Exception {
    int capacity = 10;
    BlockingQueue<Integer> queue = new ArrayBlockingQueue<Integer>(capacity);

    int numWorkers = 2;
    Worker[] workers = new Worker[numWorkers];
    for (int i = 0; i < workers.length; i++) {
      workers[i] = new Worker(queue);
      workers[i].start();
    }

    for (int i = 0; i < 10; i++) {
      queue.put(i);
    }
  }
}

class Worker extends Thread {
  BlockingQueue<Integer> q;

  Worker(BlockingQueue<Integer> q) {
    this.q = q;
  }

  public void run() {
    try {
      while (true) {
        Integer x = q.take();
        if (x == null) {
          break;
        }
        System.out.println(x);
      }
    } catch (InterruptedException e) {
    }
  }
}

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
/*from  ja v  a2 s  .c o m*/
public class Main {
  public static void main(String[] args) {
    final BlockingQueue<Character> bq = new ArrayBlockingQueue<Character>(26);
    final ExecutorService executor = Executors.newFixedThreadPool(2);
    Runnable producer;
    producer = new Runnable() {
      public void run() {
        for (char ch = 'A'; ch <= 'F'; ch++) {
          try {
            bq.put(ch);
            System.out.println("putting:"+ch);
          } catch (InterruptedException ie) {
            assert false;
          }
        }
      }
    };
    executor.execute(producer);
    Runnable consumer;
    consumer = new Runnable() {
      public void run() {
        char ch = '\0';
        do {
          try {
            ch = bq.take();
            System.out.println("getting:"+ch);
          } catch (InterruptedException ie) {
          }
        } while (ch != 'F');
        executor.shutdownNow();
      }
    };
    executor.execute(consumer);
  }
}

/*// ja v  a  2  s  .  c  om
   This program is a part of the companion code for Core Java 8th ed.
   (http://horstmann.com/corejava)

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/


import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Scanner;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;

/**
 * @version 1.0 2004-08-01
 * @author Cay Horstmann
 */
public class Main
{
   public static void main(String[] args)
   {
      String directory = "c:/";
      String keyword = "Java";

      final int FILE_QUEUE_SIZE = 10;
      final int SEARCH_THREADS = 100;

      BlockingQueue<File> queue = new ArrayBlockingQueue<File>(FILE_QUEUE_SIZE);

      FileEnumerationTask enumerator = new FileEnumerationTask(queue, new File(directory));
      new Thread(enumerator).start();
      for (int i = 1; i <= SEARCH_THREADS; i++)
         new Thread(new SearchTask(queue, keyword)).start();
   }
}

/**
 * This task enumerates all files in a directory and its subdirectories.
 */
class FileEnumerationTask implements Runnable
{
   /**
    * Constructs a FileEnumerationTask.
    * @param queue the blocking queue to which the enumerated files are added
    * @param startingDirectory the directory in which to start the enumeration
    */
   public FileEnumerationTask(BlockingQueue<File> queue, File startingDirectory)
   {
      this.queue = queue;
      this.startingDirectory = startingDirectory;
   }

   public void run()
   {
      try
      {
         enumerate(startingDirectory);
         queue.put(DUMMY);
      }
      catch (InterruptedException e)
      {
      }
   }

   /**
    * Recursively enumerates all files in a given directory and its subdirectories
    * @param directory the directory in which to start
    */
   public void enumerate(File directory) throws InterruptedException
   {
      File[] files = directory.listFiles();
      for (File file : files)
      {
         if (file.isDirectory()) enumerate(file);
         else queue.put(file);
      }
   }

   public static File DUMMY = new File("");

   private BlockingQueue<File> queue;
   private File startingDirectory;
}

/**
 * This task searches files for a given keyword.
 */
class SearchTask implements Runnable
{
   /**
    * Constructs a SearchTask.
    * @param queue the queue from which to take files
    * @param keyword the keyword to look for
    */
   public SearchTask(BlockingQueue<File> queue, String keyword)
   {
      this.queue = queue;
      this.keyword = keyword;
   }

   public void run()
   {
      try
      {
         boolean done = false;
         while (!done)
         {
            File file = queue.take();
            if (file == FileEnumerationTask.DUMMY)
            {
               queue.put(file);
               done = true;
            }
            else search(file);
         }
      }
      catch (IOException e)
      {
         e.printStackTrace();
      }
      catch (InterruptedException e)
      {
      }
   }

   /**
    * Searches a file for a given keyword and prints all matching lines.
    * @param file the file to search
    */
   public void search(File file) throws IOException
   {
      Scanner in = new Scanner(new FileInputStream(file));
      int lineNumber = 0;
      while (in.hasNextLine())
      {
         lineNumber++;
         String line = in.nextLine();
         if (line.contains(keyword)) System.out.printf("%s:%d:%s%n", file.getPath(), lineNumber,
               line);
      }
      in.close();
   }

   private BlockingQueue<File> queue;
   private String keyword;
}