thread local example

fishercoder1534 · fishercoder1534 · commit c1818bcc5054 · 2016-08-06T12:39:29.000-07:00
diff --git a/RandomProblems/src/sporadic/thread/ThreadLocalExample.java b/RandomProblems/src/sporadic/thread/ThreadLocalExample.java
@@ -0,0 +1,49 @@
+package sporadic.thread;
+
+/**
+ * The ThreadLocal class in Java enables you to create variables that can only
+ * be read and written by the same thread. Thus, even if two threads are
+ * executing the same code, and the code has a reference to a ThreadLocal
+ * variable, then the two threads cannot see each other's ThreadLocal variables.
+ * 
+ * Since values set on a ThreadLocal object only are visible to the thread who
+ * set the value, no thread can set an initial value on a ThreadLocal using
+ * set() which is visible to all threads.
+ * Instead you can specify an initial value for a ThreadLocal object by
+ * subclassing ThreadLocal and overriding the initialValue() method. Here is how
+ * that looks:
+ * 
+ * private ThreadLocal myThreadLocal = new ThreadLocal<String>() {
+ * @Override 
+ * protected String initialValue() { return "This is the initial value"; } 
+ * };
+ */
+
+public class ThreadLocalExample {
+
+	public static class MyRunnable implements Runnable {
+
+		private ThreadLocal<Integer> threadLocal = new ThreadLocal<Integer>();
+
+		@Override
+		public void run() {
+			threadLocal.set((int) (Math.random() * 100D));
+			try {
+				Thread.sleep(2000);
+			} catch (InterruptedException e) {
+				e.printStackTrace();
+			}
+			System.out.println("threadLocal.get() is: " + threadLocal.get());
+		}
+
+		public static void main(String... args) {
+			MyRunnable sharedRunnableInstance = new MyRunnable();
+			Thread t1 = new Thread(sharedRunnableInstance);
+			Thread t2 = new Thread(sharedRunnableInstance);
+
+			t1.start();
+			t2.start();
+		}
+	}
+
+}
