make future.cancel work, via Thread.currentThread().isInterrupted()

Author: yennanliu

src/main/java/threadDev/Test2.java

@@ -1,48 +1,69 @@
 package threadDev;
 
-// https://stackoverflow.com/questions/28043225/future-cancel-does-not-work
-
 import java.util.concurrent.*;
 
+/**
+ *  future cancel fixing (modified by gpt)
+ *
+ *  - boolean c = future.cancel(true);
+ *
+ *
+ *  1. Check for Interruption in the Loop:
+ * 	  - Within the infinite loop, I added a check if (Thread.currentThread().isInterrupted())
+ * 	    to break the loop if the thread is interrupted.
+ *
+ * 	2.	Thread Interruption Handling:
+ * 	  - When future.cancel(true) is called, it interrupts the thread running the task.
+ * 	    The check within the loop ensures that the thread stops executing when it is interrupted.
+ *
+ * 	3.	Executor Shutdown:
+ * 	  - The executor.shutdown() is still called in the finally block
+ * 	    to ensure that the executor is properly shut down,
+ * 	    but now the thread running the task will properly exit when interrupted.
+ *
+ *
+ */
 public class Test2 {
   public static void main(String[] args) {
 
-    Runnable r =
-        new Runnable() {
-          @Override
-          public void run() {
-            try {
-              while (!Thread.currentThread().isInterrupted()) {
-                for (; ; ) {
-                  System.out.println(
-                          "--> Thread name : "
-                                  + Thread.currentThread().getName()
-                                  + ", id = "
-                                  + Thread.currentThread().getId());
-                  System.out.println("i = ");
-                }
+    Runnable r = new Runnable() {
+      @Override
+      public void run() {
+        try {
+          while (!Thread.currentThread().isInterrupted()) {
+            int iteration = 0;
+            for (; ; ) {
+              System.out.println(
+                      "--> Thread name : "
+                              + Thread.currentThread().getName()
+                              + ", id = "
+                              + Thread.currentThread().getId() + ", iteration = " + iteration);
+              iteration += 1;
+              /**
+               *  NOTE !!! how we quit iteration when future.cancel(true) is called
+               *
+               *  Thread Interruption Handling:
+               * 	•	When future.cancel(true) is called, it interrupts the thread running the task. The check within the loop ensures that the thread stops executing when it is interrupted.
+               *
+               */
+              if (Thread.currentThread().isInterrupted()) {
+                System.out.println("Thread interrupted, exiting...");
+                break;
               }
-
-              //              for (; ; ) {
-              //                System.out.println("i = ");
-              //              }
-              //              for (int i = 0; i < 10; i++) {
-              //                System.out.println("i = " + i);
-              //              }
-
-            } finally {
-              System.out.println("FINALLY");
             }
           }
-        };
+        } finally {
+          System.out.println("FINALLY");
+        }
+      }
+    };
 
     ExecutorService executor = Executors.newSingleThreadExecutor();
 
     Future<?> future = executor.submit(r);
     try {
       future.get(3, TimeUnit.SECONDS);
     } catch (TimeoutException e) {
-
       System.out.println(">>> (before) future.cancel");
       boolean c = future.cancel(true);
       System.out.println(">>> (after) future.cancel");
@@ -56,5 +77,4 @@ public void run() {
       System.out.println("END");
     }
   }
-
-}
+}