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  • What is the purpose of Templates in iWork Pages

    - by AntonAL
    As we launch Pages 09, it prompts us to choose the item from "Text processing" and "Templates". What is the purpose of "Templates" ? Actually, i expect from template the definition of document styles and common layout. Also, i expect to create the normal document from Template. But, i didn't noticed all of that, while working with iWork Pages 09. All, what i can do - is just to create the template ... and what next to do with it ? I don't understand the logical continuation of the workflow, means by Pages, when we have to deal with templates ...

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  • Performance implications of Synchronous Sockets vs Asynchronous Sockets

    - by Akash Kava
    We are trying to build an SMTP Server to receive mail notifications from various clients over internet. As each of the communication will be longer and it needs to log everything, doing this Asynchronous way is little challenging as well as by using Socket's Asynchronous methods we are not sure of how flow of control and error handling happens. Previously we wrote lot of server/client apps but we always used Synchronous sockets, reason being they are longer sessions and each session also has lot of local data to manage and parsing messages etc. Does anyone have any experience over real performance differences between these two methods? Async calls use ThreadPool which we have experienced many times to just die for no reason. And we fail to restart threadpool etc. In one way Request-Response protocol of HTTP, Async Sockets makes sense, but SMTP/IMAP etc protocols are longer and they have interleaved messages plus state machine of server. So Async methods are really complicated to program. However if anyone can share the performance of Sockets, it will be helpful.

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  • Asynchronous sockets in C#

    - by IVlad
    I'm confused about the correct way of using asynchronous socket methods in C#. I will refer to these two articles to explain things and ask my questions: MSDN article on asynchronous client sockets and devarticles.com article on socket programming. My question is about the BeginReceive() method. The MSDN article uses these two functions to handle receiving data: private static void Receive(Socket client) { try { // Create the state object. StateObject state = new StateObject(); state.workSocket = client; // Begin receiving the data from the remote device. client.BeginReceive( state.buffer, 0, StateObject.BufferSize, 0, new AsyncCallback(ReceiveCallback), state); } catch (Exception e) { Console.WriteLine(e.ToString()); } } private static void ReceiveCallback( IAsyncResult ar ) { try { // Retrieve the state object and the client socket // from the asynchronous state object. StateObject state = (StateObject) ar.AsyncState; Socket client = state.workSocket; // Read data from the remote device. int bytesRead = client.EndReceive(ar); if (bytesRead > 0) { // There might be more data, so store the data received so far. state.sb.Append(Encoding.ASCII.GetString(state.buffer,0,bytesRead)); // Get the rest of the data. client.BeginReceive(state.buffer,0,StateObject.BufferSize,0, new AsyncCallback(ReceiveCallback), state); } else { // All the data has arrived; put it in response. if (state.sb.Length > 1) { response = state.sb.ToString(); } // Signal that all bytes have been received. receiveDone.Set(); } } catch (Exception e) { Console.WriteLine(e.ToString()); } } While the devarticles.com tutorial passes null for the last parameter of the BeginReceive method, and goes on to explain that the last parameter is useful when we're dealing with multiple sockets. Now my questions are: What is the point of passing a state to the BeginReceive method if we're only working with a single socket? Is it to avoid using a class field? It seems like there's little point in doing it, but maybe I'm missing something. How can the state parameter help when dealing with multiple sockets? If I'm calling client.BeginReceive(...), won't all the data be read from the client socket? The devarticles.com tutorial makes it sound like in this call: m_asynResult = m_socClient.BeginReceive (theSocPkt.dataBuffer,0,theSocPkt.dataBuffer.Length, SocketFlags.None,pfnCallBack,theSocPkt); Data will be read from the theSocPkt.thisSocket socket, instead of from the m_socClient socket. In their example the two are one and the same, but what happens if that is not the case? I just don't really see where that last argument is useful or at least how it helps with multiple sockets. If I have multiple sockets, I still need to call BeginReceive on each of them, right?

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  • How to write Asynchronous LINQ query?

    - by Morgan Cheng
    After I read a bunch of LINQ related stuff, I suddenly realized that no articles introduce how to write asynchronous LINQ query. Suppose we use LINQ to SQL, below statement is clear. However, if the SQL database responds slowly, then the thread using this block of code would be hindered. var result = from item in Products where item.Price > 3 select item.Name; foreach (var name in result) { Console.WriteLine(name); } Seems that current LINQ query spec doesn't provide support to this. Is there any way to do asynchronous programming LINQ? It works like there is a callback notification when results are ready to use without any blocking delay on I/O.

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  • What sense does asynchronous IO make if the thread is blocked anyway (see example)

    - by codymanix
    Hello, I found an example for async ftp upload on msdn which does the following (snippet): // Asynchronously get the stream for the file contents. request.BeginGetRequestStream( new AsyncCallback (EndGetStreamCallback), state ); // Block the current thread until all operations are complete. waitObject.WaitOne(); The thing what I do not understand here is, which sense does asynchronous IO make if the thread is blocked anyway with an explicit waithandle. I always thought the advantage of asynchronous IO was that the user/programm does not have to wait.

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  • Asynchronous email processing in Java web application

    - by Denise
    Hi everyone, I would like to implement asynchronous email sending in my web application when users register for a new account. This is so that if there is a problem or delay in sending the email message (e.g. the mail server is down or the network connection to the mail server is slow) the user won't be kept waiting for the sending to complete. My web app is built using Spring and Hibernate's implementation of JPA. What would be the best and most reliable way for me to implement asynchronous email processing in this web application? I am thinking about persisting the email information in a database table which is then regularly polled by a Quartz (http://www.opensymphony.com/quartz/) scheduled job for updates and when it finds new unsent emails, it attempts to send them. Is this a reasonable way of implementing what I want? Thanks.

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  • Converting Asynchronous Programming Model (Begin/End methods) into event-based asynchronous model?

    - by David
    Let's say I have code that uses the Asynchronous Programming Model, i.e. it provides the following methods as a group which can be used synchronously or asynchronously: public MethodResult Operation(<method params>); public IAsyncResult BeginOperation(<method params>, AsyncCallback callback, object state); public MethodResult EndOperation(IAsyncResult ar); What I want to do is wrap this code with an additional layer that will transform it into the event-driven asynchronous model, like so: public void OperationAsync(<method params>); public event OperationCompletedEventHandler OperationCompleted; public delegate void OperationCompletedEventHandler(object sender, OperationCompletedEventArgs e); Does anyone have any guidance (or links to such guidance) on how to accomplish this?

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  • Asynchronous Processing in JBoss 6 ("Comet")

    - by chris_l
    edit: Retagged as tomcat, since this is really a question about the Tomcat embedded inside JBoss 6, rather than JBoss itself I have an extremely simple servlet, which works on Glassfish v3. It uses Servlet 3.0 Asynchronous Processing. Here's a simplified version (which doesn't do much): @WebServlet(asyncSupported=true) public class SimpleServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { final AsyncContext ac = request.startAsync(); ac.setTimeout(3000); } } On JBoss 6.0.0 (Milestone 2), I get the following Exception: java.lang.IllegalStateException: The servlet or filters that are being used by this request do not support async operation at org.apache.catalina.connector.Request.startAsync(Request.java:3096) at org.apache.catalina.connector.Request.startAsync(Request.java:3090) at org.apache.catalina.connector.RequestFacade.startAsync(RequestFacade.java:990) at playcomet.SimpleServlet.doGet(SimpleServlet.java:18) at javax.servlet.http.HttpServlet.service(HttpServlet.java:734) ... Do I have to do anything special to enable Asynchronous Processing in JBoss 6? Or do I need an additional deployment descriptor? ...

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  • Implementing an interface using an asynchronous WCF service?

    - by John K.
    Hello, I am trying to figure out if it is possible to implement a .NET interface, where the interface method has to return something and you are implementing that particular interface method with an asynchronous WCF service? Hopefully you should already see the issue I am encountering. Here is the interface: public interface IDataService { IDataServiceResponse SendDataRequest(); } IDataServiceResponse is supposed to represent a simple container that holds the result of my asynchronous WCF callback. Here is the code snippet where I am implementing the interface method, SendDataRequest() public IDataServiceResponse SendDataRequest() { InitializeDataServiceParameters(); // Call the web service asynchronously, here.... _client.BeginQueryJobs(_parameters, DataServiceQueryCallBack, _client); // How do I return _dataServiceResponse, if I am calling the WCF service // asynchronously?? return _dataServiceResponse; } And the callback method signature: void DataServiceQueryCallBack(IAsyncResult result) { // ... implementation code } Thanks in advance, John

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  • Django Asynchronous Processing

    - by freyrs
    Hello all, I have a bunch of Django requests which executes some mathematical computations ( written in C and executed via a Cython module ) which may take an indeterminate amount ( on the order of 1 second ) of time to execute. Also the requests don't need to access the database. Right now everything is synchronous ( using Gunicorn with sync worker types ) but I'd like to make this asynchronous and nonblocking. I am very new to asynchronous Django, and so my question is what is the best stack for doing this. Is this sort of process something a task queue is well suited for? Would anyone recommend Tornado + Celery + RabbitMQ, or perhaps something else? Thanks in advance!

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  • Why are Asynchronous processes not called Synchronous?

    - by Balk
    So I'm a little confused by this terminology. Everyone refers to "Asynchronous" computing as running different processes on seperate threads, which gives the illusion that these processes are running at the same time. This is not the definition of the word asynchronous. a·syn·chro·nous –adjective 1. not occurring at the same time. 2. (of a computer or other electrical machine) having each operation started only after the preceding operation is completed. What am I not understanding here?

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  • Convert info pages to man pages

    - by mbac32768
    I was invited to re-post this question with less opinion, so if it seems familiar, that's why. How can I convert info pages into man pages? I used to have a shell one liner that flattened an entire info document into a single flat page, suitable for navigating with less, but I seem to have lost it. Thanks!

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  • adding tagged / dynamic pages in sitemap

    - by sam
    ive got a blog thats been running for about a year ive made about 200 posts, and there should be about 220 pages to index (additional pages for about / contact ect). When i go to crawl the site i get 1900 pages because of all the pages that are related to tags ive used in my blogs these 70% of these pages only contain one blog post. When submitting my site map to google should i exclude all pages with /tagged/ in the url so ill only be submitting unqiue pages, or should i submit the full site map ?

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  • Building Publishing Pages in Code

    - by David Jacobus
    Originally posted on: http://geekswithblogs.net/djacobus/archive/2013/10/27/154478.aspxOne of the Mantras we developers try to follow: Ensure that the solution package we deliver to the client is complete.  We build Web Parts, Master Pages, Images, CSS files and other artifacts that we push to the client with a WSP (Solution Package) And then we have them finish the solution by building their site pages by adding the web parts to the site pages.       I am a proponent that we,  the developers,  should minimize this time consuming work and build these site pages in code.  I found a few blogs and some MSDN documentation but not really a complete solution that has all these artifacts working in one solution.   What I am will discuss and provide a solution for is a package that has: 1.  Master Page 2.  Page Layout 3.  Page Web Parts 4.  Site Pages   Most all done in code without the development team or the developers having to finish up the site building process spending a few hours or days completing the site!  I am not implying that in Development we do this. In fact,  we build these pages incrementally testing our web parts, etc. I am saying that the final action in our solution is that we take all these artifacts and add them to the site pages in code, the client then only needs to activate a few features and VIOLA their site appears!.  I had a project that had me build 8 pages like this as part of the solution.   In this blog post, I am taking a master page solution that I have called DJGreenMaster.  On My Office 365 Development Site it looks like this:     It is a generic master page for a SharePoint 2010 site Along with a three column layout.  Centered with a footer that uses a SharePoint List and Web Part for the footer links.  I use this master page a lot in my site development!  Easy to change the color and site logo with a little CSS.   I am going to add a few web parts for discussion purposes and then add these web parts to a site page in code.    Lets look at the solution package for DJ Green Master as that will be the basis project for building the site pages:   What you are seeing  is a complete solution to add a Master Page to a site collection which contains: 1.  Master Page Module which contains the Master Page and Page Layout 2.  The Footer Module to add the Footer Web Part 3.  Miscellaneous modules to add images, JQuery, CSS and subsite page 4.  3 features and two feature event receivers: a.  DJGreenCSS, used to add the master page CSS file to Style Sheet Library and an Event Receiver to check it in. b.  DJGreenMaster used to add the Master Page and Page Layout.  In an Event Receiver change the master page to DJGreenMaster , create the footer list and check the files in. c.  DJGreenMasterWebParts add the Footer Web Part to the site collection. I won’t go over the code for this as I will give it to you at the end of this blog post. I have discussed creating a list in code in a previous post.  So what we have is the basis to begin what is germane to this discussion.  I have the first two requirements completed.  I need now to add page web parts and the build the pages in code.  For the page web parts, I will use one downloaded from Codeplex which does not use a SharePoint custom list for simplicity:   Weather Web Part and another downloaded from MSDN which is a SharePoint Custom Calendar Web Part, I had to add some functionality to make the events color coded to exceed the built-in 10 overlays using JQuery!    Here is the solution with the added projects:     Here is a screen shot of the Weather Web Part Deployed:   Here is a screen shot of the Site Calendar with JQuery:     Okay, Now we get to the final item:  To create Publishing pages.   We need to add a feature receiver to the DJGreenMaster project I will name it DJSitePages and also add a Event Receiver:       We will build the page at the site collection level and all of the code necessary will be contained in the event receiver.   Added a reference to the Microsoft.SharePoint.Publishing.dll contained in the ISAPI folder of the 14 Hive.   First we will add some static methods from which we will call  in our Event Receiver:   1: private static void checkOut(string pagename, PublishingPage p) 2: { 3: if (p.Name.Equals(pagename, StringComparison.InvariantCultureIgnoreCase)) 4: { 5: 6: if (p.ListItem.File.CheckOutType == SPFile.SPCheckOutType.None) 7: { 8: p.CheckOut(); 9: } 10:   11: if (p.ListItem.File.CheckOutType == SPFile.SPCheckOutType.Online) 12: { 13: p.CheckIn("initial"); 14: p.CheckOut(); 15: } 16: } 17: } 18: private static void checkin(PublishingPage p,PublishingWeb pw) 19: { 20: SPFile publishFile = p.ListItem.File; 21:   22: if (publishFile.CheckOutType != SPFile.SPCheckOutType.None) 23: { 24:   25: publishFile.CheckIn( 26:   27: "CheckedIn"); 28:   29: publishFile.Publish( 30:   31: "published"); 32: } 33: // In case of content approval, approve the file need to add 34: //pulishing site 35: if (pw.PagesList.EnableModeration) 36: { 37: publishFile.Approve("Initial"); 38: } 39: publishFile.Update(); 40: }   In a Publishing Site, CheckIn and CheckOut  are required when dealing with pages in a publishing site.  Okay lets look at the Feature Activated Event Receiver: 1: public override void FeatureActivated(SPFeatureReceiverProperties properties) 2: { 3:   4:   5:   6: object oParent = properties.Feature.Parent; 7:   8:   9:   10: if (properties.Feature.Parent is SPWeb) 11: { 12:   13: currentWeb = (SPWeb)oParent; 14:   15: currentSite = currentWeb.Site; 16:   17: } 18:   19: else 20: { 21:   22: currentSite = (SPSite)oParent; 23:   24: currentWeb = currentSite.RootWeb; 25:   26: } 27: 28:   29: //create the publishing pages 30: CreatePublishingPage(currentWeb, "Home.aspx", "ThreeColumnLayout.aspx","Home"); 31: //CreatePublishingPage(currentWeb, "Dummy.aspx", "ThreeColumnLayout.aspx","Dummy"); 32: }     Basically we are calling the method Create Publishing Page with parameters:  Current Web, Name of the Page, The Page Layout, Title of the page.  Let’s look at the Create Publishing Page method:   1:   2: private void CreatePublishingPage(SPWeb site, string pageName, string pageLayoutName, string title) 3: { 4: PublishingSite pubSiteCollection = new PublishingSite(site.Site); 5: PublishingWeb pubSite = null; 6: if (pubSiteCollection != null) 7: { 8: // Assign an object to the pubSite variable 9: if (PublishingWeb.IsPublishingWeb(site)) 10: { 11: pubSite = PublishingWeb.GetPublishingWeb(site); 12: } 13: } 14: // Search for the page layout for creating the new page 15: PageLayout currentPageLayout = FindPageLayout(pubSiteCollection, pageLayoutName); 16: // Check or the Page Layout could be found in the collection 17: // if not (== null, return because the page has to be based on 18: // an excisting Page Layout 19: if (currentPageLayout == null) 20: { 21: return; 22: } 23:   24: 25: PublishingPageCollection pages = pubSite.GetPublishingPages(); 26: foreach (PublishingPage p in pages) 27: { 28: //The page allready exists 29: if ((p.Name == pageName)) return; 30:   31: } 32: 33:   34:   35: PublishingPage newPage = pages.Add(pageName, currentPageLayout); 36: newPage.Description = pageName.Replace(".aspx", ""); 37: // Here you can set some properties like: 38: newPage.IncludeInCurrentNavigation = true; 39: newPage.IncludeInGlobalNavigation = true; 40: newPage.Title = title; 41: 42: 43:   44:   45: 46:   47: //build the page 48:   49: 50: switch (pageName) 51: { 52: case "Homer.aspx": 53: checkOut("Courier.aspx", newPage); 54: BuildHomePage(site, newPage); 55: break; 56:   57:   58: default: 59: break; 60: } 61: // newPage.Update(); 62: //Now we can checkin the newly created page to the “pages” library 63: checkin(newPage, pubSite); 64: 65: 66: }     The narrative in what is going on here is: 1.  We need to find out if we are dealing with a Publishing Web.  2.  Get the Page Layout 3.  Create the Page in the pages list. 4.  Based on the page name we build that page.  (Here is where we can add all the methods to build multiple pages.) In the switch we call Build Home Page where all the work is done to add the web parts.  Prior to adding the web parts we need to add references to the two web part projects in the solution. using WeatherWebPart.WeatherWebPart; using CSSharePointCustomCalendar.CustomCalendarWebPart;   We can then reference them in the Build Home Page method.   Let’s look at Build Home Page: 1:   2: private static void BuildHomePage(SPWeb web, PublishingPage pubPage) 3: { 4: // build the pages 5: // Get the web part manager for each page and do the same code as below (copy and paste, change to the web parts for the page) 6: // Part Description 7: SPLimitedWebPartManager mgr = web.GetLimitedWebPartManager(web.Url + "/Pages/Home.aspx", System.Web.UI.WebControls.WebParts.PersonalizationScope.Shared); 8: WeatherWebPart.WeatherWebPart.WeatherWebPart wwp = new WeatherWebPart.WeatherWebPart.WeatherWebPart() { ChromeType = PartChromeType.None, Title = "Todays Weather", AreaCode = "2504627" }; 9: //Dictionary<string, string> wwpDic= new Dictionary<string, string>(); 10: //wwpDic.Add("AreaCode", "2504627"); 11: //setWebPartProperties(wwp, "WeatherWebPart", wwpDic); 12:   13: // Add the web part to a pagelayout Web Part Zone 14: mgr.AddWebPart(wwp, "g_685594D193AA4BBFABEF2FB0C8A6C1DD", 1); 15:   16: CSSharePointCustomCalendar.CustomCalendarWebPart.CustomCalendarWebPart cwp = new CustomCalendarWebPart() { ChromeType = PartChromeType.None, Title = "Corporate Calendar", listName="CorporateCalendar" }; 17:   18: mgr.AddWebPart(cwp, "g_20CBAA1DF45949CDA5D351350462E4C6", 1); 19:   20:   21: pubPage.Update(); 22:   23: } Here is what we are doing: 1.  We got  a reference to the SharePoint Limited Web Part Manager and linked/referenced Home.aspx  2.  Instantiated the a new Weather Web Part and used the Manager to add it to the page in a web part zone identified by ID,  thus the need for a Page Layout where the developer knows the ID’s. 3.  Instantiated the Calendar Web Part and used the Manager to add it to the page. 4. We the called the Publishing Page update method. 5.  Lastly, the Create Publishing Page method checks in the page just created.   Here is a screen shot of the page right after a deploy!       Okay!  I know we could make a home page look much better!  However, I built this whole Integrated solution in less than a day with the caveat that the Green Master was already built!  So what am I saying?  Build you web parts, master pages, etc.  At the very end of the engagement build the pages.  The client will be very happy!  Here is the code for this solution Code

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  • Ajax Asynchronous in IE - Error "The Data Necessary to Complete This Operation is Not Yet Available"

    - by Supernovah
    Hey there. I have a 100% valid Ajax model written in Javascript with a few inputs I use being, Get or Post method, What page to communicate with, What String to send to that page and What element on my own page I might be fiddling with when I receive my response. The problem is that, should I set the request to Asynchronous (Hence Ajax), IE returns the error "The Data Necessary to Complete This Operation is Not Yet Available" in the onreadystatechange event where all I do is check if the readystate is 4 and the status is 200. The error doesn't come up in Firefox or Chrome as I would exepect as the Ajax is Asynchronous. Heres a snippet from the Post method xmlhttp.open("POST", commPage, true); xmlhttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded; charset=UTF-8"); xmlhttp.onreadystatechange = function() { if (xmlhttp.readyState == 4 && xmlhttp.status == 200) { j = xmlhttp.responseText; i.innerHTML = j; } } xmlhttp.send(str); Edit: I should point out that in IE, I'm using the ActiveX Control - Msxml2.XMLHTTP or Microsoft.XMLHTTP or whichever returns true first.

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  • how to do asynchronous http requests with epoll and python 3.1

    - by flow
    there is an interesting page http://scotdoyle.com/python-epoll-howto.html about how to do asnchronous / non-blocking / AIO http serving in python 3. there is the tornado web server which does include a non-blocking http client. i have managed to port parts of the server to python 3.1, but the implementation of the client requires pyCurl and seems to have problems (with one participant stating how ‘Libcurl is such a pain in the neck’, and looking at the incredibly ugly pyCurl page i doubt pyCurl will arrive in py3+ any time soon). now that epoll is available in the standard library, it should be possible to do asynchronous http requests out of the box with python. i really do not want to use asyncore or whatnot; epoll has a reputation for being the ideal tool for the task, and it is part of the python distribution, so using anything but epoll for non-blocking http is highly counterintuitive (prove me wrong if you feel like it). oh, and i feel threading is horrible. no threading. i use stackless. people further interested in the topic of asynchronous http should not miss out on this talk by peter portante at PyCon2010; also of interest is the keynote, where speaker antonio rodriguez at one point emphasizes the importance of having up-to-date web technology libraries right in the standard library.

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  • Asynchronous callback - gwt

    - by sprasad12
    Hi, I am using gwt and postgres for my project. On the front end i have few widgets whose data i am trying to save on to tables at the back-end when i click on "save project" button(this also takes the name for the created project). In the asynchronous callback part i am setting more than one table. But it is not sending the data properly. I am getting the following error: org.postgresql.util.PSQLException: ERROR: insert or update on table "entitytype" violates foreign key constraint "entitytype_pname_fkey" Detail: Key (pname)=(Project Name) is not present in table "project". But when i do the select statement on project table i can see that the project name is present. Here is how the callback part looks like: oksave.addClickHandler(new ClickHandler(){ @Override public void onClick(ClickEvent event) { if(erasync == null) erasync = GWT.create(EntityRelationService.class); AsyncCallback<Void> callback = new AsyncCallback<Void>(){ @Override public void onFailure(Throwable caught) { } @Override public void onSuccess(Void result){ } }; erasync.setProjects(projectname, callback); for(int i = 0; i < boundaryPanel.getWidgetCount(); i++){ top = new Integer(boundaryPanel.getWidget(i).getAbsoluteTop()).toString(); left = new Integer(boundaryPanel.getWidget(i).getAbsoluteLeft()).toString(); if(widgetTitle.startsWith("ATTR")){ type = "regular"; erasync.setEntityAttribute(name1, name, type, top, left, projectname, callback); } else{ erasync.setEntityType(name, top, left, projectname, callback); } } } Question: Is it wrong to set more than one in the asynchronous callback where all the other tables are dependent on a particular table? when i say setProjects in the above code isn't it first completed and then moved on to the next one? Please any input will be greatly appreciated. Thank you.

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  • Understanding F# Asynchronous Programming

    - by Yin Zhu
    I kind of know the syntax of asynchronous programming in F#. E.g. let downloadUrl(url:string) = async { let req = HttpWebRequest.Create(url) // Run operation asynchronously let! resp = req.AsyncGetResponse() let stream = resp.GetResponseStream() // Dispose 'StreamReader' when completed use reader = new StreamReader(stream) // Run asynchronously and then return the result return! reader.AsyncReadToEnd() } In F# expert book (and many other sources), they say like let! var = expr simply means "perform the asynchronous operation expr and bind the result to var when the operation completes. Then continue by executing the rest of the computation body" I also know that a new thread is created when performing async operation. My original understanding was that there are two parallel threads after the async operation, one doing I/O and one continuing to execute the async body at the same time. But in this example, I am confused at let! resp = req.AsyncGetResponse() let stream = resp.GetResponseStream() What happens if resp has not started yet and the thread in the async body wants to GetResponseStream? Is this a possible error? So maybe my original understanding was wrong. The quoted sentences in the F# expert book actually means that "creating a new thread, hang the current thread up, when the new thread finishes, wake up the body thread and continue", but in this case I don't see we could save any time. In the original understanding, the time is saved when there are several independent IO operations in one async block so that they could be done at the same time without intervention with each other. But here, if I don't get the response, I cannot create the stream; only I have stream, I can start reading the stream. Where's the time gained?

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  • Authentication using cookie key with asynchronous callback

    - by greg
    I need to write authentication function with asynchronous callback from remote Auth API. Simple authentication with login is working well, but authorization with cookie key, does not work. It should checks if in cookies present key "lp_login", fetch API url like async and execute on_response function. The code almost works, but I see two problems. First, in on_response function I need to setup secure cookie for authorized user on every page. In code user_id returns correct ID, but line: self.set_secure_cookie("user", user_id) does't work. Why it can be? And second problem. During async fetch API url, user's page has loaded before on_response setup cookie with key "user" and the page will has an unauthorized section with link to login or sign on. It will be confusing for users. To solve it, I can stop loading page for user who trying to load first page of site. Is it possible to do and how? Maybe the problem has more correct way to solve it? class BaseHandler(tornado.web.RequestHandler): @tornado.web.asynchronous def get_current_user(self): user_id = self.get_secure_cookie("user") user_cookie = self.get_cookie("lp_login") if user_id: self.set_secure_cookie("user", user_id) return Author.objects.get(id=int(user_id)) elif user_cookie: url = urlparse("http://%s" % self.request.host) domain = url.netloc.split(":")[0] try: username, hashed_password = urllib.unquote(user_cookie).rsplit(',',1) except ValueError: # check against malicious clients return None else: url = "http://%s%s%s/%s/" % (domain, "/api/user/username/", username, hashed_password) http = tornado.httpclient.AsyncHTTPClient() http.fetch(url, callback=self.async_callback(self.on_response)) else: return None def on_response(self, response): answer = tornado.escape.json_decode(response.body) username = answer['username'] if answer["has_valid_credentials"]: author = Author.objects.get(email=answer["email"]) user_id = str(author.id) print user_id # It returns needed id self.set_secure_cookie("user", user_id) # but session can's setup

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  • Building asynchronous cache pattern with JSP

    - by merweirdo
    I have a JSP that will take some 8 minutes to render. The code logic itself can not be made more efficient (it will update often and be updated by basically a pointy haired boss). I tried wrapping it with a caching layer like <%@ taglib uri="/WEB-INF/classes/oscache.tld" prefix="oscache" %> <oscache:cache time="60"> <div class="pagecontent"> ..... my logic </div> </oscache:cache> This is nice until the 60 seconds is over. The next query after that blocks until the 8 minutes of rendering is done with again. I would need a way to build a pattern something like: If there is no version of the dynamic content in the cache run the actual logic (and populate the cache for subsequent requests) If there is a non-expired version of the dynamic content in the cache serve the output of the JSP logic from the cache If there is an expired version of the dynamic content in the cache serve the output of the JSP logic still from the cache AND run the JSP logic in the background so that the cache gets updated transparently to the user - avoiding the user have to wait for 8 minutes I found out that at least EHCache might be able to do some asynchronous cache updating but it did not sadly seem to apply to the JSP tags... Also I have to take in 10-20 parameters for the actual logic of the JSP and some of them should be used as a key for caching. Code example and/or pointers would be greatly appreciated. I do not frankly care if the solution provided is extremely ugly. I just want a simple 5 minute caching with asynchronous cache update taking into account some parameters as a key.

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