YAPC::EU 2018 Glasgow Update!

Task/Determine-if-only-one-instance-is-running/Java/determine-if-only-one-instance-is-running.java

@@ -1,23 +1,35 @@
-import java.io.IOExeception;
+import java.io.IOException;
 import java.net.InetAddress;
 import java.net.ServerSocket;
 import java.net.UnknownHostException;
 
 public class SingletonApp
 {
-	private static final int PORT = 12345;		// random large port number
-	private static ServerSocket s;
+    private static final int PORT = 65000;  // random large port number
+    private static ServerSocket s;
 
-	// static initializer
-	{
-		try {
-			s = new ServerSocket(PORT, 10, InetAddress.getLocalHost());
-		} catch (UnknownHostException e) {
-			// shouldn't happen for localhost
-		} catch (IOException e) {
-			// port taken, so app is already running
-			System.exit(0);
-		}
-	}
-	// main() and rest of application...
+    // static initializer
+    static {
+        try {
+            s = new ServerSocket(PORT, 10, InetAddress.getLocalHost());
+        } catch (UnknownHostException e) {
+            // shouldn't happen for localhost
+        } catch (IOException e) {
+            // port taken, so app is already running
+            System.out.print("Application is already running,");
+            System.out.println(" so terminating this instance.");
+            System.exit(0);
+        }
+    }
+
+    public static void main(String[] args) {
+        System.out.print("OK, only this instance is running");
+        System.out.println(" but will terminate in 10 seconds.");
+        try {
+            Thread.sleep(10000);
+            if (s != null && !s.isClosed()) s.close();
+        } catch (Exception e) {
+            System.err.println(e);
+        }
+    }
 }

Task/Determine-if-only-one-instance-is-running/Ring/determine-if-only-one-instance-is-running.ring

@@ -0,0 +1,22 @@
+# Project : Determine if only one instance is running
+
+task = "ringw.exe"
+taskname = "tasklist.txt"
+remove(taskname)
+system("tasklist >> tasklist.txt")
+fp = fopen(taskname,"r")
+tasks = read("tasklist.txt")
+counttask = count(tasks,task)
+if counttask > 0
+   see task + " running in " + counttask + " instances" + nl
+else
+   see task + " is not running" + nl
+ok
+
+func count(cString,dString)
+     sum = 0
+     while substr(cString,dString) > 0
+           sum++
+           cString = substr(cString,substr(cString,dString)+len(string(sum)))
+     end
+     return sum

Task/Determine-if-only-one-instance-is-running/Scala/determine-if-only-one-instance-is-running.scala

@@ -0,0 +1,23 @@
+import java.io.IOException
+import java.net.{InetAddress, ServerSocket}
+
+object SingletonApp extends App {
+  private val port = 65000
+
+  try {
+    val s = new ServerSocket(port, 10, InetAddress.getLocalHost)
+  }
+  catch {
+    case _: IOException =>
+      // port taken, so app is already running
+      println("Application is already running, so terminating this instance.")
+      sys.exit(-1)
+  }
+
+  println("OK, only this instance is running but will terminate in 10 seconds.")
+
+  Thread.sleep(10000)
+
+  sys.exit(0)
+
+}