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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   5  * This code is free software; you can redistribute it and/or modify it
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   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
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  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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  23  * questions.
  24  */
  25 
  26 package javafx.concurrent;
  27 
  28 import javafx.concurrent.mocks.EpicFailTask;
  29 import javafx.concurrent.mocks.InfiniteTask;
  30 import javafx.concurrent.mocks.RunAwayTask;
  31 import javafx.concurrent.mocks.SimpleTask;
  32 import org.junit.Before;
  33 import org.junit.Test;
  34 
  35 import static org.junit.Assert.*;
  36 
  37 /**
  38  * Tests what happens to a Task if it is canceled in each of the various
  39  * states that a Task may be in.
  40  */
  41 public class TaskCancelTest {
  42     /**
  43      * Since the InfiniteTask never ends (normally), I can test it from the
  44      * ready, scheduled, running, cancelled, and failed states. I can't use
  45      * it for testing what happens when the task succeeds though.
  46      */
  47     private InfiniteTask task;
  48 
  49     @Before public void setup() {
  50         task = new InfiniteTask();
  51     }
  52 
  53     /**
  54      * Since the task begins in the ready state, I can just cancel it and
  55      * see what happens.
  56      */
  57     @Test public void cancellingA_READY_TaskShouldChangeStateTo_CANCELLED() {
  58         assertTrue(task.cancel());
  59         assertEquals(Task.State.CANCELLED, task.getState());
  60         assertTrue(task.isDone());
  61     }
  62 
  63     /**
  64      * I have some cheap mechanism for simulating the scheduling of a Task
  65      * (it just changes the Task state correctly). So put it in the
  66      * Scheduled state and then cancel it and see what happens.
  67      */
  68     @Test public void cancellingA_SCHEDULED_TaskShouldChangeStateTo_CANCELLED() {
  69         task.simulateSchedule();
  70         assertTrue(task.cancel());
  71         assertEquals(Task.State.CANCELLED, task.getState());
  72         assertTrue(task.isDone());
  73     }
  74 
  75     /**
  76      * Since the task is an infinitely running task, and since there is a
  77      * semaphore on the AbstractTask that tells me when certain state
  78      * transitions have occurred, I can simply fire up another thread and
  79      * run the infinite task, and then wait for that semaphore to trip. When
  80      * it does, I know that we're running (and will never leave that state)
  81      * so I can go ahead and then cancel it.
  82      *
  83      * @throws Exception shouldn't throw anything unless th.join fails
  84      */
  85     @Test public void cancellingA_RUNNING_TaskShouldChangeStateTo_CANCELLED() throws Exception {
  86         Thread th = new Thread(task);
  87         th.start();
  88         task.runningSemaphore.acquire();
  89         assertTrue(task.cancel());
  90         th.join();
  91 
  92         assertEquals(Task.State.CANCELLED, task.getState());
  93         // TODO why is this commented out?
  94 //        assertNull(task.getException());
  95         assertNull(task.getValue());
  96         assertTrue(task.isDone());
  97     }
  98 
  99     /**
 100      * In this case I don't want to use the infinite task, so I'll just
 101      * use a SimpleTask instead
 102      */
 103     @Test public void cancellingA_SUCCEEDED_TaskShouldNotChangeTo_CANCELLED() {
 104         Task t = new SimpleTask();
 105         t.run();
 106         assertFalse(t.cancel());
 107         assertEquals(Task.State.SUCCEEDED, t.getState());
 108         assertTrue(t.isDone());
 109     }
 110 
 111     /**
 112      * Although I could end up using the infinite task for this one, I'm going
 113      * to go ahead and reuse the epic fail task instead
 114      */
 115     @Test public void cancellingA_FAILED_TaskShouldNotChangeTo_CANCELLED() {
 116         Task t = new EpicFailTask();
 117         t.run();
 118         assertFalse(t.cancel());
 119         assertEquals(Task.State.FAILED, t.getState());
 120         assertTrue(t.isDone());
 121     }
 122 
 123     /**
 124      *
 125      */
 126     @Test public void aFreeRunningCancelledTaskReturnValueShouldBeIgnored() throws Exception {
 127         RunAwayTask runAway = new RunAwayTask() {
 128                 protected void loop(int count) throws Exception {
 129                 }
 130         };
 131         Thread th = new Thread(runAway);
 132         th.start();
 133         runAway.runningSemaphore.acquire();
 134         assertTrue(runAway.cancel());
 135         runAway.stopLooping.set(true);
 136         th.join();
 137 
 138         assertEquals(Task.State.CANCELLED, runAway.getState());
 139         // TODO why is this commented out?
 140 //        assertNull(task.getException());
 141         assertNull(runAway.getValue());
 142         assertTrue(runAway.isDone());
 143     }
 144 }