Java - If statement in foreach not called -


i trying check if string in collection of strings. (the strings in case topics activemq broker) iterate through topic list , compare topics searched 1 (save in variable "compare"). "topic.gettopicname()" definately returns string not why varaible count not set 1 eventhough condition true in 1 case. statement in if clause never executed. overlooking something?

 public arraylist<string> gettopics() throws remoteexception {                try {                   // topics strings broker                  activemqconnectionfactory connectionfactory = new activemqconnectionfactory("tcp://localhost:61616");                 activemqconnection connection;                 connection = (activemqconnection) connectionfactory.createconnection();                 connection.start();                 destinationsource ds = connection.getdestinationsource();                  set<activemqtopic>  topics = ds.gettopics();                 string compare = "physical";                 int count = 0;                   for(activemqtopic topic : topics){                           system.out.println(topic.gettopicname());                         if(compare == topic.gettopicname()) {                              system.out.println("found " + topic.gettopicname());                             count = count + 1;                           }                  }                      if(count == 0){                           system.out.println("no topic found");                      }                      else    system.out.println("topic found");                    } catch (jmsexception e) {                 // todo auto-generated catch block                 e.printstacktrace();             }                    return null;   }

i can't debug code because i'm not sure in activemqconnectionfactory can provide advice.

try adding 

if(compare == topic.gettopicname()) {                          system.out.println("found " + topic.gettopicname());                         count = count + 1;                       }                     else {                         system.out.println("not found " + topic.gettopicname());                     }

the following else statement can see happens when should equal. additionally, think should comparing string using .equals() not == since strings objects.

you can see string comparison using == fail in following code

public static void main(string[] args) {         string compare = "physical";         string somestring = new string("physical");         string[] words = {"test", "cheese", "physical", somestring};          (string s: words) {             if(s == compare) {                 system.out.println(s + " == " + compare);             }             else {                 system.out.println(s + " " + "!= " + compare);             }         }         system.out.println("--------------------------------------------------------");         (string s: words) {             if(s.equals(compare)) {                 system.out.println(s + " == " + compare);             }             else {                 system.out.println(s + " " + "!= " + compare);             }         }     }

prints 

test != physical cheese != physical physical == physical physical != physical -------------------------------------------------------- test != physical cheese != physical physical == physical physical == physical

Comments

Post a Comment

Popular posts from this blog

Is there a better way to structure post methods in Class Based Views -

i'm using class based views in django , never specify url in ajax calls , omit action parameter in form because know these requests go through post method of class based view. notice view - profile page make many requests depending on user updating on page - post method become convoluted , if/else mess example: def post(self, request, *args, **kwargs): # handle user changing available date if request.post.get('availabledate') != none: self.updateavailabledate(request) return jsonresponse({'result':'success'}) if request.post.get('newprojectname') != none: creative_user = creativeuserprofile.objects.get(id = request.user.id) project = project.create_project(creative_user, request.post['newprojectname']) project.save() return jsonresponse({'projectid': project.id }) if request.post.get('projectimage') != none , request.files['file']: proj
Read more

performance - Why is XCHG reg, reg a 3 micro-op instruction on modern Intel architectures? -

i'm doing micro-optimization on performance critical part of code , came across sequence of instructions (in at&t syntax): add %rax, %rbx mov %rdx, %rax mov %rbx, %rdx i thought had use case xchg allow me shave instruction , write: add %rbx, %rax xchg %rax, %rdx however, dimay found agner fog's instruction tables , xchg 3 micro-op instruction 2 cycle latency on sandy bridge, ivy bridge, broadwell, haswell , skylake. 3 whole micro-ops , 2 cycles of latency! 3 micro-ops throws off 4-1-1-1 cadence , 2 cycle latency makes worse original in best case since last 2 instructions in original might execute in parallel. now... cpu might breaking instruction micro-ops equivalent to: mov %rax, %tmp mov %rdx, %rax mov %tmp, %rdx where tmp anonymous internal register , suppose last 2 micro-ops run in parallel latency 2 cycles. given register renaming occurs on these micro-architectures, though, doesn't make sense me done way. why wouldn't register renamer
Read more

jquery - Responsive Navbar with Sub Navbar -

good day, forgive me nav vocabulary not best. if question confusing apologize. i'm working on navigation bar needs centered on page @ 768px , above. items in nav open (or perhaps toggle) subnav lives directly below. these nav should appear centered on page. i have been able work through responsive portion of nav bar, having main items align vertically , sub nav menu of each item roll out below, , gave them indent separation. working well. however, issue not responsive side, behavior @ width greater 768px. happens toggling menu's sub navigation pushes other main items down page below sub nav. here's code: $(document).ready(function () { //stick in fixed 100% height behind navbar don't wrap $('#slide-nav.navbar-inverse').after($('<div class="inverse" id="navbar-height-col"></div>')); $('#slide-nav.navbar-default').after($('<div id="navbar-height-col"></d
Read more