How to detect infinite loop and stop execution?

[rohts-patil]

Let's say I have an MVEL expression that is causing an infinite loop. Is there any API in the MVEL library that allows me to set a timeout for executing the expression?

Sample expression:-
Serializable compiled = MVEL.compileExpression("while(true)\n" + "System.out.println(\"Hello\");");
Map<String, Object> vars = Collections.singletonMap("a", (Object) Collections.emptyMap());
MVEL.executeExpression(compiled, vars);

This will keep on executing.

[MalcolmOdd]

I don't believe MVEL supports this directly but you could do something like this:

      ExecutorService executor = Executors.newSingleThreadExecutor();
      Serializable compiled = MVEL.compileExpression("while(true)\n" + "System.out.println(\"Hello\");");
      Map<String, Object> vars = Collections.singletonMap("a", (Object) Collections.emptyMap());
      Future<Object> futureResult = executor.submit(() -> MVEL.executeExpression(compiled, vars));
      try {
	  futureResult.get(5, TimeUnit.SECONDS);
      }
      catch(TimeoutException tex) {
	  System.out.println("Timeout detected");
      }

[rohts-patil]

This won't work. The original thread won't be interrupted and the execution would go on, no?