java - Correct way to get output from ExecutorCompletionService -


i'm using executorcompletionservice result of jobs completes execution. pseudocode this-

instantiate fixedthreadpool executor, exec instantiate executorcompletionservice, completionservice for(tasklist) {    completionservice.submit(sometask) } exec.shutdown(); whie(!exec.isshutdown()) { //line 1    task t = completionservice.take(); //line 2 }

as know, shutdown() waits completion of submitted tasks , long there task in progress while condition on line1 returns true , code goes inside loop take completed task queue , waits if necessary.
now, i've observed problem above code in control gets blocked on line2 if there no more tasks in progress, tasks have been completed.
think it's because when last task completed , added completion queue, threadpoolexecutor resumes shutdown process there no more pending submitted tasks. while still shutting down, next iteration takes place , isshutdown() returns false goes inside loop , gets blocked take() call though there no more tasks. maybe it's time between last take call , pool shutting down properly. thinking in right direction?
thinking if right way use , result completionservice? fix this, can replace while on line1 for(tasklist) in order avoid isshutdown call. there's thing, best practice shutdown executor , result completionservice or first collect result , shutdown execturo in end?

try use isterminated() instead of isshutoown(). best choice use awaittermination() method instead of creating loop.


Comments

Post a Comment

Popular posts from this blog

How to understand 2 main() functions after using uftrace to profile the C++ program? -

i trying uftrace profile following simple c++ program: #include <iostream> class { public: a() {std::cout << "a created" << std::endl;} ~a() {std::cout << "a destroyed" << std::endl;} }; int main() { a; return 0; } the profile result this: # uftrace a.out created destroyed # duration tid function 2.026 [ 4828] | __cxa_atexit(); [ 4828] | main() { [ 4828] | __static_initialization_and_destruction_0() { 89.397 [ 4828] | std::ios_base::init::init(); 0.768 [ 4828] | __cxa_atexit(); 93.029 [ 4828] | } /* __static_initialization_and_destruction_0 */ 94.425 [ 4828] | } /* main */ [ 4828] | main() { [ 4828] | a::a() { 11.104 [ 4828] | std::operator <<(); 10.825 [ 4828] | std::basic_ostream::operator <<(); 24.514 [ 4828] | } /* a::a */ [ 4828] | a::~a() { 0.978 [ 4828] | ...
Read more

c# - Update a combobox from a presenter (MVP) -

i using mvp in project, new in mvp. have 2 comboboxes. when select option in combobox, combobox should filled new data. this action in presenter. view 'view1' in presenter, , introduced combobox1 , combobox2 properties in 'view1', because need 'datasource', 'displaymember', 'valuemember' , 'refresh()' in method below. but, when using pattern, enough send property like public string combobox2 { { return combobox1.selectedvalue.tosstring(); } } into presenter not whole combobox. how can solve problem? public void onselectedindexchangedcombobox1() { if (view1.combobox1.selectedindex == -1) { return; } datatable dt = tools.getdatatable("a path"); var query = (from o in dt.asenumerable() o.field<string>("afield") == farmerview.combobox1.selectedvalue.tostring() orderby o.field<string>("anotherfield") select...
Read more

How to put a lock and transaction on table using spring 4 or above using jdbcTemplate and annotations like @Transactional? -

i trying put lock on table while writing on table , if happened in between roll-back . trying convert below code lock table test_g1 read; lock table test_g write; -- begin; start transaction; insert test_g1 values(143); insert test_g values(145); select * test_g1; select * test_g; rollback; select * test_g; unlock tables; how convert above code @transactional spring jdbctemplate code? @transactional(rollbackfor={dataaccessexception.class}) public void test(){ jdbctemplate.execute("insert test1 (id, nam) values (4, 'a')"); throw new dataaccessexception("error") { }; } here trying throw error, insert statement should rollback it's not happening . thanks edit-1 attaching code , doing in jdbcdaoimpl.java , mentioned problem comment above test() . app.java package com.cgiri.javabrains.spring4; import org.springframework.beans.factory.annotation.autowired; import org.springframework.context.applic...
Read more