Implemented the error handling in case of commucation failures

spring-boot-samples/spring-boot-sample-websocket/src/main/java/org/springframework/boot/samples/websocket/snake/SnakeTimer.java

@@ -22,6 +22,7 @@ import java.util.Iterator;
 import java.util.Timer;
 import java.util.TimerTask;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CopyOnWriteArrayList;
 
 import org.apache.juli.logging.Log;
 import org.apache.juli.logging.LogFactory;
@@ -78,14 +79,16 @@ public class SnakeTimer {
     }
 
     public static void broadcast(String message) throws Exception {
-        for (Snake snake : SnakeTimer.getSnakes()) {
-			try {
-				snake.sendMessage(message);
-			}
-			catch (Throwable ex) {
-				// if Snake#sendMessage fails the client should be removed
-			}
-		}
+        Collection<Snake> snakes = new CopyOnWriteArrayList<>(SnakeTimer.getSnakes());
+        for (Snake snake : snakes) {
+            try {
+                snake.sendMessage(message);
+            }
+            catch (Throwable ex) {
+                // if Snake#sendMessage fails the client is removed
+                removeSnake(snake);
+            }
+        }
     }
 
 

spring-boot-samples/spring-boot-sample-websocket/src/test/java/org/springframework/boot/samples/websocket/snake/SnakeTimerTests.java

@@ -0,0 +1,24 @@
+package org.springframework.boot.samples.websocket.snake;
+
+import org.junit.Test;
+
+import java.io.IOException;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+import static org.mockito.Matchers.anyString;
+import static org.mockito.Mockito.doThrow;
+import static org.mockito.Mockito.mock;
+
+public class SnakeTimerTests {
+
+    @Test
+    public void removeDysfunctionalSnakes() throws Exception {
+        Snake snake = mock(Snake.class);
+        doThrow(new IOException()).when(snake).sendMessage(anyString());
+        SnakeTimer.addSnake(snake);
+
+        SnakeTimer.broadcast("");
+        assertThat(SnakeTimer.getSnakes().size(), is(0));
+    }
+}