javascript - jquery combining chaining when done when done and so on ... when then -

-

i have structure below need executed in order:

var task1, task2, task3, last;  initialize = $.when(function(){ ...initializing... }).done(function(){ ..initialization completed.. });  task1 = initialize.when(function(){ ..doing task1.. }).done(function(){ ..task1 completed.. });  task2 = task1.when(function(){ ..doing task2.. }).done(function(){ ..task2 completed.. });  task3 = task2.when(function(){ ..doing task3.. }).done(function(){ ..task3 completed.. });  last  = task3.when(function(){ ..doing last.. }).then(function(){ ..last completed.. });

how jquery-1.10.2?

considering above example console output be:

initializing initialization completed doing task1 task1 completed doing task2 task2 completed doing task3 task3 completed doing last last completed

when working asynchronous tasks need executed in order can wrapp them $.deferred , chain them using deffered.then():

function init() {     console.log("initializing"); }  function dotask1() {      var d = $.deferred();      console.log("synchronous part of task 1");      settimeout(function() {          console.log("asynchronous part of task 1");          d.resolve() }, 5000);      return d; }  function dotask2(resfromtask1) {     var d = $.deferred();      console.log("task2");     settimeout(function() {          console.log("asynchronous part of task 2");          d.resolve() }, 5000);       return d; }  function dolast() {     console.log("last task"); }  $.when(init()).then(dotask1).then(dotask2).done(dolast);

note dolast function get's called when deffered returned dotask2 resolved. if instance wanted run synchronous function after dotask1 before dotask2 need added this:

$.when(init()).then(dotask1).done(function() {         console.log("new synchronous function");     }).then(dotask2).done(dolast);

now both dotask2 , anonymous function run when dotask1's deferred object resolved. if anonymous function moved after dotask2:

$.when(init()).then(dotask1).then(dotask2).done(function() {         console.log("new synchronous function");     }).done(dolast);

then anonymous function , dolast function both run when deferred object returned dotask2 finishes.


Comments

Post a Comment

Popular posts from this blog

c# - How Configure Devart dotConnect for SQLite Code First? -

-
can configure following sample code ? when run following code, error : no entity framework provider found ado.net provider invariant name 'devart.data.sqlite' setting in machine.config <system.data> <dbproviderfactories> <add name="dotconnect sqlite" invariant="devart.data.sqlite" description="devart dotconnect sqlite" type="devart.data.sqlite.sqliteproviderfactory, devart.data.sqlite, version=4.6.287.0, culture=neutral, publickeytoken=09af7300eec23701" /> </dbproviderfactories> </system.data> after add below block code in app.config <?xml version="1.0"?> <configuration>   <configsections> <!-- more information on entity framework configuration, visit http://go.microsoft.com/fwlink/?linkid=237468 --> <section name="entityframework" type="system.data.entity.internal.configfile.entityframeworksection, entit...
Read more

java - Copying object fields -

-
what best way of copying classes when need have 2 independent variables? have simple class: public class myclass { boolean = false; string b= "not empty"; } do need make method : assign(myclass data ) { a= data.a; b= data.b; } is there automatic method copy (duplicate) objects in java? do need make method : pretty close. instead of making method, should make constructor. such constructors called copy constructor , , create them this: myclass(myclass data) { = data.a; b = data.b; } and create copy of instance, use constructor this: myclass obj1 = new myclass(); myclass obj2 = new myclass(obj1); copy constructor can tedious : using copy constructor create deep-copy can tedious, when class has mutable fields. in case, assignment create copy of reference, , not object itself. have create copy of fields (if want deep copy). can go recursive. a better way create deep copy serialize , deserialize object. why not use clone()? ...
Read more

c++ - Clear the memory after returning a vector in a function -

-
i have function processes , stores lot of data in , returns results vector of class. amount of data stored in function tremendous , want clear storage memory of function after finished job. necessary (does function automatically clear memory) or should clear memory function? update: vector<customers> process(char* const *filename, vector<int> id) { vector<customers> list_of_customers; (perform actions) return list_of_customers; } variables defined locally within function automatically released @ end of function scope. destructors objects called, should free memory allocated objects (if objects coded correctly). example of such object std::vector . anything you've allocated new must have corresponding delete release storage. try avoid doing own allocation , use raii instead, i.e. containers or smart pointers.
Read more