java - can I access a static Arraylist of Vector of another thread? in this example? -

-

having problems accessing static vector thread , class in thread. 1 class gui class called lotteryplay, has static vector called packarray, , other class called multithreader , part of shown below, runs in different thread. ideas on wrong?

the thing think of trying access static vector thread. possible?

   @override public void run() {     try {                out = new printwriter(socket.getoutputstream(), true);            in = new bufferedreader(new inputstreamreader(socket.getinputstream()));         system.out.println("streams setup new thread\n");              line = "";               while((line = in.readline())!= null){               this.messagefromclient(line);              if(!(counter > 1)){                 textsplitter(line);                 socketpack = new socketpack(socket, timestamp, address);                 lotteryplay.packarray.add(socketpack);   <<<----null pointer exception                 system.out.println("size of packarray " + lotteryplay.packarray.size());                 system.out.println();                 system.out.println("pakc array "+ lotteryplay.packarray);             }              system.out.println("from client: " + line.trim() + "\n");              }  // end while loop

exception in thread "thread-3" java.lang.nullpointerexception at.com.lotterygame.multithreader.run(multithreader.java:55) @ java.lang.thread.run(thread.java:662)

the fact you're getting nullpointerexception suggests lotteryplay.packarray null. need make sure it's initialized before use it.

if really want keep static variable, i'd advise make final, e.g.

public static final vector<socketpack> packarray = new vector<socketpack>();

however, i'd advise redesign application avoid requiring static variables. think needs data, , pass appropriately. static variables make code harder reason , test.

additionally, note although each operation in vector individually synchronized, doesn't make thread-safe. example, can't safely iterate on vector without synchronization, otherwise 1 thread modify while you're iterating. should consider collections in java.util.concurrent.


Comments

Post a Comment

Popular posts from this blog

ruby - Trying to change last to "x"s to 23 -

-
i have been playing around irb , have string looks this: irb(main):072:0> puts ["[\"4354 5432 5432 xxxxx\", \"6547 6547 8543 xxxxx\", \"2344 6543 6674 xxxxx\", \"2346 6236 7543 xxxxx\", \"1273 5585 5587 xxxxx\"]"] => nil irb(main):073:0> what want gsub last 2 "x" s of each 17 digit combination, 23 . what i've tried far (i've been using rubular): a.gsub(/\d[x]/,"23") <= grabs "x" s i'm close a.gsub(/\w[x{2}]/,"23") <= grabs "x" s grabs two digits each combination. is there easier way i'm not understanding? a.gsub(/\d{4} \d{4} \d{4} xxx\kxx/, '23') \d{4} = 4 digits what \k drop matched far. can use don't replace entire number, still able validate have in desired format.
Read more

jquery - Clone last and append item to closest class -

-
this bare-bones code on page: <div class="list-container"> <div class="single-list-item"> <button>remove</button> </div> <div class="single-list-item"> <button>remove</button> </div> <div class="single-list-item"> <button>remove</button> </div> </div> <p><button class="add-list-item">add</button></p> <div class="list-container"> <div class="single-list-item"> <button>remove</button> </div> <div class="single-list-item"> <button>remove</button> </div> <div class="single-list-item"> <button>remove</button> </div> </div> <p><button class="add-list-item">add</button></p> <di...
Read more

css - Can I use the :after pseudo-element on an input field? -

-
i trying use :after css pseudo-element on input field, not work. if use span , works ok. <style type="text/css"> .mystyle:after {content:url(smiley.gif);} .mystyle {color:red;} </style> this works (puts smiley after "buu!" , before "some more") <span class="mystyle">buuu!</span>a more this not work - colors somevalue in red, there no smiley. <input class="mystyle" type="text" value="somevalue"> what doing wrong? should use pseudo-selector? note: cannot add span around input , because being generated third-party control. :after , :before not supported in internet explorer 7 , under, on elements. it's not meant used on replaced elements such form elements (inputs) , image elements . in other words it's impossible pure css. however if using jquery can use $(".mystyle").after("add smiley here"); api docs on .after to ...
Read more