logs.add("170.36.40.12");
logs.add("124.2.84.36");
Grok grok = Grok.create("patterns/patterns", "%{IP}");
List<String> json = grok.captures(logs);
assertNotNull(json);
int i = 0;
for(String elem : json){
assertNotNull(elem);
assertEquals(elem, grok.capture(logs.get(i)));