[oll3i]

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1. package zad31;
2.  
3. import java.io.FileDescriptor;
4. import java.io.FileInputStream;
5. import java.util.concurrent.ExecutorService;
6. import java.util.concurrent.Executors;
7. import java.util.concurrent.TimeUnit;
8. import java.util.concurrent.locks.Lock;
9. import java.util.concurrent.locks.ReentrantLock;
10.  
11. import javax.swing.JOptionPane;
12.  
13. import com.sun.java_cup.internal.runtime.Scanner;
14.  
15. class Interruptible  {
16.  
17.       Lock lock = new ReentrantLock();
18.  
19.       Runnable task1 = new Runnable() {
20.          public void run() {
21.            System.out.println("Task 1 begins");
22.            try {
23.              lock.tryLock(1000, TimeUnit.SECONDS);  // próba zamknięcia rygla (czeka na wolny rygiel lub 1000 sekund)
24.              System.out.println("Task 1 entered");
25.            } catch(InterruptedException exc) {
26.                System.out.println("Task 1 interrupted");
27.            }
28.            System.out.println("Task 1 stopped");
29.          }
30.       };
31.  
32.       Runnable task2 = new Runnable() {
33.         public void run() {
34.           System.out.println("Task 2 begins");
35.           for (int i=1; i <= 600; i++) {
36.             if (Thread.currentThread().isInterrupted()) break;
37.             // jakieś obliczenie
38.             if (Thread.currentThread().isInterrupted()) break;  // chcemy przerwać możliwie najszybciej
39.             try {                                               // sleep() jest przerywane pzrez interrupt()!
40.               Thread.sleep(1000);
41.             } catch (InterruptedException exc) { break; }
42.           }
43.           System.out.println("Task 2 stopped");
44.         }
45.       };
46.  
47.  
48.       Runnable task3 = new Runnable() {
49.         Scanner scan = new Scanner( 
50.                         new FileInputStream(FileDescriptor.in).getChannel(), "Cp852");
51.         public void run() {
52.           System.out.println("Task 3 begins");
53.           System.out.print(">>");
54.           while ((scan).hasNextLine()) {
55.             try {
56.               String s = scan.nextLine();
57.               System.out.print('\n'+s + "\n>>");
58.             } catch (Exception exc) {
59.                 // Uwaga: scanner nie zgłasza wyjątków, ale przerywa dzialanie
60.                 exc.printStackTrace();
61.                 break;
62.             }
63.           }
64.           System.out.println("Task 3 stopped - " + scan.ioException());  // jaki wyjątek go przerwał?
65.         }
66.       };
67.  
68.       Interruptible() {
69.         ExecutorService exec = Executors.newCachedThreadPool();
70.  
71.         exec.execute(new Runnable() {        // wątek zamyka rygiel
72.                         public void run() {
73.                           lock.lock();
74.                         }
75.                      }
76.          );
77.         exec.execute(task1);
78.         exec.execute(task2);
79.         exec.execute(task3);
80.         JOptionPane.showMessageDialog(null, "Press Ok to stop all tasks");
81.         exec.shutdownNow();
82.       }
83.  
84.     }
85.  
86.  
87.  

why eclipse says it cannot instantiate the type Scanner

[r035198x]

Quote:

Originally Posted by oll3i

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1. package zad31;
2.  
3. import java.io.FileDescriptor;
4. import java.io.FileInputStream;
5. import java.util.concurrent.ExecutorService;
6. import java.util.concurrent.Executors;
7. import java.util.concurrent.TimeUnit;
8. import java.util.concurrent.locks.Lock;
9. import java.util.concurrent.locks.ReentrantLock;
10.  
11. import javax.swing.JOptionPane;
12.  
13. import com.sun.java_cup.internal.runtime.Scanner;
14.  
15. class Interruptible {
16.  
17.      Lock lock = new ReentrantLock();
18.  
19.      Runnable task1 = new Runnable() {
20.      public void run() {
21.      System.out.println("Task 1 begins");
22.      try {
23.      lock.tryLock(1000, TimeUnit.SECONDS); // próba zamknięcia rygla (czeka na wolny rygiel lub 1000 sekund)
24.      System.out.println("Task 1 entered");
25.      } catch(InterruptedException exc) {
26.      System.out.println("Task 1 interrupted");
27.      }
28.      System.out.println("Task 1 stopped");
29.      }
30.      };
31.  
32.      Runnable task2 = new Runnable() {
33.      public void run() {
34.      System.out.println("Task 2 begins");
35.      for (int i=1; i <= 600; i++) {
36.      if (Thread.currentThread().isInterrupted()) break;
37.      // jakieś obliczenie
38.      if (Thread.currentThread().isInterrupted()) break; // chcemy przerwać możliwie najszybciej
39.      try { // sleep() jest przerywane pzrez interrupt()!
40.      Thread.sleep(1000);
41.      } catch (InterruptedException exc) { break; }
42.      }
43.      System.out.println("Task 2 stopped");
44.      }
45.      };
46.  
47.  
48.      Runnable task3 = new Runnable() {
49.      Scanner scan = new Scanner( 
50.      new FileInputStream(FileDescriptor.in).getChannel(), "Cp852");
51.      public void run() {
52.      System.out.println("Task 3 begins");
53.      System.out.print(">>");
54.      while ((scan).hasNextLine()) {
55.      try {
56.      String s = scan.nextLine();
57.      System.out.print('\n'+s + "\n>>");
58.      } catch (Exception exc) {
59.      // Uwaga: scanner nie zgłasza wyjątków, ale przerywa dzialanie
60.      exc.printStackTrace();
61.      break;
62.      }
63.      }
64.      System.out.println("Task 3 stopped - " + scan.ioException()); // jaki wyjątek go przerwał?
65.      }
66.      };
67.  
68.      Interruptible() {
69.      ExecutorService exec = Executors.newCachedThreadPool();
70.  
71.      exec.execute(new Runnable() { // wątek zamyka rygiel
72.      public void run() {
73.      lock.lock();
74.      }
75.      }
76.      );
77.      exec.execute(task1);
78.      exec.execute(task2);
79.      exec.execute(task3);
80.      JOptionPane.showMessageDialog(null, "Press Ok to stop all tasks");
81.      exec.shutdownNow();
82.      }
83.  
84.     }
85.  
86.  
87.  

why eclipse says it cannot instantiate the type Scanner

Why not just use the scanner class in the util package

[JosAH]

I'm almost sure the OP uses Java 1.5 or newer: the concurrent packages weren't
there in Java 1.4, or the OP must've installed Doug Lea's concurrent packages
manually which I don't believe for now.

When Eclipse doesn't recognize a class because you haven't imported it yet
or you haven't imported the entire package, Eclipse can search for it. When it
finds more than one candidate it offers a choice. Eclipse found a Scanner in
the com.sun.* package as well as the java.util package.

It is never sensible to *not* read the choices offered by Eclipse and simply
bang the enter key or to press the ok key. Reading is not (yet?) supposed to
be a lost ancient form of art you know.

kind regards,

Jos