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  • Java client server sending bytes receiver listens indefinitely

    - by Rob
    Hello, I'm trying to write a Java program for Windows that involves communication with a server program located on a foreign machine.My program successfully connects to the server, successfully writes a byte array to it, and waits for a response. I know that the server is printing bytes (the response) back to me one byte at a time. I've tried using a DataInputStream object with various methods (read, readByte etc.), I've tried using a BufferedReader object with its methods (read, readLine etc.) but all the reader objects and various methods that I've used all come up against the same problem. The bytes are being successfully read (each time a byte or bytes are read, I can print them to the console, and they are what I'd expect them to be). The problem is that my reader doesn't know when to stop reading. Even if the server has sent all its bytes, the reader function on my end waits for more data, indefinitely, and so the program hangs at the read function. This problem seems to affect all the techniques that I have tried. I've been running tests with a simple client program and server program, each about 40 or 50 lines long, where the client connects to the server, and sends some bytes to it. All the techniques I've tried for the server reader result in the same problem mentioned above (the server hangs waiting for more input from the client, even though it has sent all its data). I'm really desperate for some help on this. It's important that I get this program finished soon, and it's basically complete except for this communication issue. Any help is much appreciated! -Rob

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  • Obj-C: Passing pointers to initialized classes in other classes

    - by FnGreg7
    Hey all. I initialized a class in my singleton called DataModel. Now, from my UIViewController, when I click a button, I have a method that is trying to access that class so that I may add an object to one of its dictionaries. My get/set method passes back the pointer to the class from my singleton, but when I am back in my UIViewController, the class passed back doesn't respond to methods. It's like it's just not there. I think it has something to do with the difference in passing pointers around classes or something. I even tried using the copy method to throw a copy back, but no luck. UIViewController: ApplicationSingleton *applicationSingleton = [[ApplicationSingleton alloc] init]; DataModel *dataModel = [applicationSingleton getDataModel]; [dataModel retrieveDataCategory:dataCategory]; Singleton: ApplicationSingleton *m_instance; DataModel *m_dataModel; - (id) init { NSLog(@"ApplicationSingleton.m initialized."); self = [super init]; if(self != nil) { if(m_instance != nil) { return m_instance; } NSLog(@"Initializing the application singleton."); m_instance = self; m_dataModel = [[DataModel alloc] init]; } NSLog(@"ApplicationSingleton init method returning."); return m_instance; } -(DataModel *)getDataModel { DataModel *dataModel_COPY = [m_dataModel copy]; return dataModel_COPY; } For the getDataModel method, I also tried this: -(DataModel *)getDataModel { return m_dataModel; } In my DataModel retrieveDataCategory method, I couldn't get anything to work. I even just tried putting a NSLog in there but it never would come onto the console. Any ideas?

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  • HTTP Negotiate windows vs. Unix server implementation using python-kerberos

    - by ondra
    I tried to implement a simple single-sign-on in my python web server. I have used the python-kerberos package which works nicely. I have tested it from my Linux box (authenticating against active directory) and it was without problem. However, when I tried to authenticate using Firefox from Windows machine (no special setup, just having the user logged into the domain + added my server into negotiate-auth.trusted-uris), it doesn't work. I have looked at what is sent and it doesn't even resemble the things the Linux machine sends. This Microsoft description of the process pretty much resembles the way my interaction from Linux works, but the Windows machine generally sends a very short string, which doesn't even resemble the things microsoft documentation states, and when base64 decoded, it is something like 12 zero bytes followed by 3 or 4 non-zero bytes (GSS functions then return that it doesn't support such scheme) Either there is something wrong with the client Firefox settings, or there is some protocol which I am supposed to follow for the Negotiate protocol, but which I cannot find any reference anywhere. Any ideas what's wrong? Do you have any idea what protocol I should by trying to find, as it doesn' look like SPNEGO, at least from MS documentation.

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  • Boost's "cstdint" Usage

    - by patt0h
    Boost's C99 stdint implementation is awfully handy. One thing bugs me, though. They dump all of their typedefs into the boost namespace. This leaves me with three choices when using this facility: Use "using namespace boost" Use "using boost::[u]<type><width>_t" Explicitly refer to the target type with the boost:: prefix; e.g., boost::uint32_t foo = 0; Option ? 1 kind of defeats the point of namespaces. Even if used within local scope (e.g., within a function), things like function arguments still have to be prefixed like option ? 3. Option ? 2 is better, but there are a bunch of these types, so it can get noisy. Option ? 3 adds an extreme level of noise; the boost:: prefix is often = to the length of the type in question. My question is: What would be the most elegant way to bring all of these types into the global namespace? Should I just write a wrapper around boost/cstdint.hpp that utilizes option ? 2 and be done with it? Also, wrapping the header like so didn't work on VC++ 10 (problems with standard library headers): namespace Foo { #include <boost/cstdint.hpp> using namespace boost; } using namespace Foo; Even if it did work, I guess it would cause ambiguity problems with the ::boost namespace.

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  • Submit button on nested form submits the outer form in IE7

    - by Mike Christensen
    I have the following code on my Home.aspx page: <form id="frmJump" method="post" action="Views/ViewsHome.aspx"> <input name="JumpProject" /><input type="submit" value="Go" /> </form> However, when I click the "Go" button, the page posts back to Home.aspx rather than going to ViewsHome.aspx. I even tried adding some script to force the form to submit: <input name="JumpProject" onkeypress="if(event.keyCode == 13) { this.form.submit(); return false; }" /> But still even if I press ENTER, the Home.aspx page is reloaded. The only thing I can see that might be borking things is this form is actually a child form of the main POSTBACK form that ASP.NET injects into the page. I'm sure there's something stupid I'm missing and this post will get 800 downvotes instantly banishing me back into the n00b realm, but perhaps I haven't gotten enough sleep lately and I'm missing something stupid. This is on IE7 and an ASP.NET 4.0 backend. I also have jQuery libraries loaded on the page incase jQuery can improve this somehow. Thanks!

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  • What's the next steps for moving from appengine to full django?

    - by tomcritchlow
    Hey guys, I'm super new to programming and I've been using appengine to help me learn python and general coding. I'm getting better quickly and I'm loving it all the way :) Appengine was awesome for allowing me to just dive into writing my app and getting something live that works (see http://www.7bks.com/). But I'm realising that the longer I continue to learn on appengine the more I'm constraining myself and locking myself into a single system. I'd like to move to developing on full django (since django looks super cool!). What are my next steps? To give you a feel for my level of knowledge: I'm not a unix user I'm not familiar with command line controls (I still use appengine/python completely via the appengine SDK) I've never programmed in anything other than python, anywhere other than appengine I know the word SQL, but don't know what MySQL is really or how to use it. So, specifically: What are the skills I need to learn to get up and running with full django/python? If I'm going to host somewhere else I suppose I'll need to learn some sysadmin type skills (maybe even unix?). Is there anywhere that offers easy hosting (like appengine) but that supports django? I hear such great things about heroku I'm considering switching to RoR and going there I appreciate that I'm likely not quite ready to move away from appengine just yet but I'm a fiercely passionate learner (http://www.7bks.com/blog/179001) and would love it if I knew all the steps I needed to learn so I could set about learning them. At the moment, I don't even know what the steps are I need to learn! Thank you very much. Sorry this isn't a specific programming question but I've looked around and haven't found a good how-to for someone of my level of experience and I think others would appreciate a good roadmap for the things we need to learn to get up and running. Thanks, Tom PS - if anyone is in London and fancies showing me the ropes in person that would be super awesome :)

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  • Adobe flex dateField

    - by JonoB
    I have some code as follows: private function onComboChange(evt:Event):void { var temp:Date = df_date.selectedDate; temp.date += 5; df_dateDue.selectedDate = new Date(temp); } In essence, I am trying to add 5 days onto the selected date in df_date, and put that date into df_dateDue. This fires off via an EventListener on a combobox. Both df_date and df_dateDue are dateFields. OK, so the first time that I run this, it works fine; df_date stays the same and df_dateDue is set to 5 days past df_date. However, the next time that I run it, df_dateDue increments by 10 days from df_date, the next time by 15, and so on. So, stepping through the code shows that somehow df_date has become linked to the temp var, and that the temp var is not resetting itself each time the function is called. Example: df_date = 01 Jan, df_dateDue = 01 Jan. Fire off the event, df_date = 01 Jan, df_dateDue = 06 Jan Fire off the event again. At this point, var temp = 06 Jan (even though df_date still shows 01 Jan), and df_dateDue is then set to 11 Jan Fire off the event again. At this point var temp = 11 Jan (even though df_date = 01 Jan), and df_dateDue is then set to 16 Jan What am I missing here?

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  • Index an array expression directly in PostgreSQL

    - by wich
    I'm trying to insert data into a table from a template table. I need to rewrite one of the columns for which I wanted to use a directly indexed array expression, but I can't seem to find how to do this, if it is even possible. The scenario: create table template ( id integer, index integer, foo integer); insert into template values (0, 1, 23), (0, 2, 18), (0, 3, 16), (0, 4, 7), (1, 1, 17), (1, 2, 26), (1, 3, 11), (1, 4, 3); create table data ( data_id integer, foo integer); Now what I'd like to do is the following: insert into data select (array[3,7,5,2])[index], foo from template where id = 1; But this doesn't work, the (array[3,7,5,2])[index] syntax isn't valid. I tried a few variants, but was unable to get anything working and wasn't able to find the correct syntax in the docs, nor even whether this is at all possible or not. As a current workaround I've devised the following, but it is less than ideal, from an elegance perspective at least, but it may also be a performance hit, I haven't looked into that yet. insert into data select arr[index], foo from template, (select array[3,7,5,2] as arr) as q where id = 1; If anyone could suggest a (better) alternative to accomplish this I'd like to hear that as well.

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  • How to reliably identify users across Internet?

    - by amn
    I know this is a big one. In fact, it may be used for some SO community wiki. Anyways, I am running a website that DOES NOT use explicit authentication of users. It's public as in open to everybody. However, due to the nature of the service, some users need to be locked out due to misbehavior. I am currently blocking IP addresses, but I am aware of the supposed fact that many people purposefully reset their DHCP client cache to have their ISP assign them new addresses. Is that a fact? I think it certainly is a lucrative possibility for some people who want to circumvent being denied access. So IPs turn out to be a suboptimal way of dealing with this. But there is nothing else, is it? MAC addresses don't survive on WAN (change from hop to hop?), and even if they did - these can also be spoofed, although I think less easily than IP renewal. Cookies and even Flash cookies are out of the question, because there are tons of "tutorials" how to wipe these, and those intent on wreaking havoc on Internet are well aware and well equipped against such rudimentary measures I would employ. Is there anything else to lean on? I was thinking heuristical profiling - collecting available data from client-side and forming some key with it, but have not gone as far as to implementing it - is it an option?

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  • not able to run c/cpp execs in eclipse cdt

    - by user1658323
    i installed eclipse and then cdt on an ubuntu system recently and was trying to make the first runnable c/c++ proj.. i installed g++ also, and then created the first executable cpp 'Hello World' project some files are created... then some issues... 1) even though Build Automatically is selected, I have to goto the project n do a Build Project to build it manually, and this i have to do everytime i make a change 2) After Building manually, there are some new folders created with Binaries and Debug files and i can see g++ commands in the console being executed. The project binary is output both to debug n binaries folder. But i am not able to run these through the Green Play Button or any other way in eclipse. Even Run configuration is not showing any option for c/C++ proj.. though i can goto terminal and run the binary myself through ./ But i want to be able to run n debug this through eclipse. plz help in fixing me this problem as i really love eclipse n have some c/cpp assignments coming soon.. Console info on doing a manual project build - Build of configuration Debug for project qwe ** make all Building file: ../src/qwe.cpp Invoking: GCC C++ Compiler g++ -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"src/qwe.d" -MT"src/qwe.d" -o "src/qwe.o" "../src/qwe.cpp" Finished building: ../src/qwe.cpp Building target: qwe Invoking: GCC C++ Linker g++ -o "qwe" ./src/qwe.o Finished building target: qwe Build Finished **

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  • How can I intelligently group rows of integers for a faceted search?

    - by Alastair
    I'm not even quite sure what terms I should be using for what I want, so any advice on what I'm even asking for would be very welcome. Basically, my web site lists user-generated accommodations. Each has a rent price, which users will be able to query in our new faceted search box. Users search by city, and within each city I'd like to present a different rent grouping. That is to say that in City #1, if we have listings ranging from $200 - $1000, I'd like to present checkboxes for: less than $300 $301 - $500 $501 - $700 more than $700 However, if City #2 has values that range from $500 - $1500, I want the ranges above to change accordingly. So, if I say that I want 5 or 6 range options in each city, I think I have two options: Take the min and max values and just split the difference. I don't like this idea because one listing with a rent of $10,000 will throw the whole scale off. Intelligently calculate the ranges using means, medians etc. Number 2 is what I need help with. I'm a web developer that gets logic, but was never strong on math and statistics at school. Can anyone point me towards a guide that'll help me figure this out?

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  • Refactoring or Rewriting Monolithic PHP Spaghetti Codebase

    - by nategood
    I've inherited a really poorly designed PHP spaghetti code project. It's been gaining a good bit of traffic recently and is starting to have performance issues on top of the poor monolithic code base. Its maxing out performance on a chunky 16GB dedicated machine when it really shouldn't be. I'm planning on doing some performance tweaks right off the bat to help the performance issue, but this still won't really help the horrible code base. The team is small but expecting to grow very soon. I've read Joel's article on the troubles of doing a complete rewrite and see the concerns. But how bad does the code base have to be before you consider a rewrite? There is PHP handling logic interjected into what one would usually consider a "view". Even worse, in some places SQL statements are in these same files! The only real separation of presentation and logic are a few PHP scripts that serve as function libraries. These scripts do most of the ORM stuff... if you can even call it that. Trying to slowly refractor this seems like a nightmare. Open to your thoughts and opinions... however not interested in hearing, "Run away, Run away!".

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  • Learning Java, how to type text on canvas?

    - by Voley
    I'm reading a book by Eric Roberts - Art and science of java and it got an excersise that I can't figure out - You have to make calendar, with GRect's, 7 by 6, that goes ok, the code part is easy, but also you have to type the numbers of the date on those rectangles, and it's kinda hard for me, there is nothing about it in the book. I tried using GLabel thing, but here arises the problem that I need to work on those numbers, and it says "can't convert from int to string and vice versa". GLabel (string, posX, posY) - it is not accepting int as a parameter, only string, I even tried typecasting, still not working. For example I want to make a loop int currentDate = 1; while (currentDate < 31) { add(new Glabel(currentDate, 100, 100); currentDate++; This code is saying that no man, can't convert int to string. If i try changing currentDate to string, it works, but I got a problem with calculation, as I can't manipulate with number in string, it doesn't even allow to typecast it into int. How can I fix it? Maybe there is another class or method to type the text over those rectangles? I know about println but it doen't have any x or y coordinates, so I can't work with it. And I think it's only for console programs.

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  • Stopping cookies being set from a domain (aka "cookieless domain") to increase site performance

    - by Django Reinhardt
    I was reading in Google's documentation about improving site speed. One of their recommendations is serving static content (images, css, js, etc.) from a "cookieless domain": Static content, such as images, JS and CSS files, don't need to be accompanied by cookies, as there is no user interaction with these resources. You can decrease request latency by serving static resources from a domain that doesn't serve cookies. Google then says that the best way to do this is to buy a new domain and set it to point to your current one: To reserve a cookieless domain for serving static content, register a new domain name and configure your DNS database with a CNAME record that points the new domain to your existing domain A record. Configure your web server to serve static resources from the new domain, and do not allow any cookies to be set anywhere on this domain. In your web pages, reference the domain name in the URLs for the static resources. This is pretty straight forward stuff, except for the bit where it says to "configure your web server to serve static resources from the new domain, and do not allow any cookies to be set anywhere on this domain". From what I've read, there's no setting in IIS that allows you to say "serve static resources", so how do I prevent ASP.NET from setting cookies on this new domain? At present, even if I'm just requesting a .jpg from the new domain, it sets a cookie on my browser, even though our application's cookies are set to our old domain. For example, ASP.NET sets an ".ASPXANONYMOUS" cookie that (as far as I'm aware) we're not telling it to do. Apologies if this is a real newb question, I'm new at this! Thanks.

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  • Browser window popups - risks and special features

    - by Sandeepan Nath
    1. What exactly is the security risk with popups? The new browsers provide settings to block window popups (on blocking, sites with active popups display a message to user). What exactly is the security risk with popups? If allowing popups can execute something dangerous, then the main window can too. Is it not the case. I think I don't know about some special powers of window popups. 2. Any special features of popup windows? Take for example the HDFC bank netbanking site. The entire netbanking session happens in a new window popup and a user neither manually edit the URL or paste the URL in the main browser window. it does not work. Is a popup window needed for this feature? Does it improve security? (Asking because everything that is there in this site revolves around security - so they must have done that for a reason too). Why otherwise they would implement the entire netbanking on a popup window? 3. Is it possible to override browser's popup blocking settings Lastly, the HDFC site succcessfully displays popup window even when in the browser settings popups are blocked. So, how do they do it? Is that a browser hack? To see this - go to http://hdfcbank.com/ Under the "Login to your account" section select "HDFC Bank NetBanking" and click the "Login" button. You can verify that even if popups are blocked/popup blocker is enabled in the browser settings, this site is able to display popups. The answers to this question say that it is not possible to display popup windows if it has been blocked in browser settings. Solved Concluded with Pointy's solution and comments under that. Here is a fiddle demonstrating the same.

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  • UILabel + IRR, KRW and KHR currencies with wrong symbol

    - by serb
    Hi, I'm experiencing issues when converting decimal to currency for Korean Won, Cambodian Riel and Iranian Rial and showing the result to the UILabel text. Conversion itself passes just fine and I can see correct currency symbol at the debugger, even the NSLog prints the symbol well. If I assign this NSString instance to the UILabel text, the currency symbol is shown as a crossed box instead of the correct symbol. There is no other code between, does not matter what font I use. I tried to print ? (Korean Won) using the unicode value (0x20A9) or even using UTF8 representation (\xe2\x82\xa9), but all I get is the crossed box on the label. Any other supported currency in iPhone SDK and NSLocale (nearly 170 currencies) works perfectly fine no matter how exotic the currency is. Anyone else experiencing the same problem? Is there a "cure" for this? Thanks EDIT: -(NSString *)decimalToCurrency:(NSDecimalNumber *)value byLocale:(NSLocale *)locale { NSNumberFormatter *fmt = [[NSNumberFormatter alloc] init]; [fmt setLocale: locale]; [fmt setNumberStyle: NSNumberFormatterCurrencyStyle]; NSString *res = [fmt stringFromNumber: value]; [fmt release]; return res; } lbValue.text = [self decimalToCurrency: price byLocale: koreanLocale];

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  • Open source real life license examples: yours or others

    - by donpal
    I'm aware of the usual list of open source licenses, so I'm not even going to list it here. What I'd like to ask is about your open source projects (whether out or planned for the future), and why you're planning to choose a certain license over the other. Basically say I went for X license because I wanted Y and that other license didn't provide it for me. I understand that the language itself can make a difference in the choice of license: interpreted languages like PHP vs. compiled languages like Java. I'm mostly interested in hearing about PHP projects, but of course additional insights are welcome. You may even have chosen that particular language for a licensing reason. Ideally I want to hear answers from people who were involved in the actual project (i.e. your own project), because that usually means you've put some thought into the license yourself and understand the implications of that license. But examples of existing projects that aren't your own are OK. Please just say why you think that license was good/bad for them. But first-hand experience is preferred. Looking forward to hearing some informative input.

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  • How to get the most out of a 3 month intern?

    - by firoso
    We've got a software engineering intern coming in who's fairly competent and shows promise. There's one catch: we have him for 3 months full time and can't count on anything past that. He still has a year of school left, which is why we can't say for sure that we have him past 3 months. We have a specific project we're putting him on. How can we maximize his productivity while still giving him a positive learning experience? He wants to learn about development cycles and real-world software engineering. Anything that you think would be critical that you wish you had learned earlier? Nearly six months later: He's preformed admirably and even I have learned a lot from him. Thank you all for the input. Now I want to provide feedback to YOU! He has benefited most from sitting down and writing code. However, he has had a nasty history of bad software engineering practices which I'm trying to replace with good habits (properly finishing a method before moving on, not hacking code together, proper error channeling, etc). He has also really gained a lot by feeling involved in design decisions, even if most of the time they're related to my own design plans.

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  • How do you use FastInfoset with JAXWS?

    - by Chris Kessel
    I've got code that looks like it should be correct based on what I can find, but the spewed output doesn't indicate that it's using FastInfoset. My understanding is the Accept should indicate it can accept Fastinfoset and the response would actually use it, meaning it's not text/xml as the response type. Any idea what I'm doing wrong? I've scoured with Google and I'm having a hard time finding much detail on how to use FastInfoset at all. JaxWsProxyFactoryBean factory = new JaxWsProxyFactoryBean(); factory.getInInterceptors().add(new LoggingInInterceptor()); factory.getOutInterceptors().add(new LoggingOutInterceptor()); factory.setServiceClass( C360Server.class); factory.setAddress("http://localhost:8501/cxfcontroller/cl_v5"); C360Server client = (C360Server)factory.create(); ((BindingProvider)client).getRequestContext().put( "com.sun.xml.ws.client.ContentNegotiation", "optimistic"); C360Request requestTrans = new C360Request(); ... code to fill in the request ... C360Response response = client.findContacts( requestTrans ); The logging doesn't seem to indicate FastInfoset is even attempted though: INFO: Outbound Message --------------------------- ID: 1 Address: http://localhost:8501/cxfcontroller/cl_v5 Encoding: UTF-8 Content-Type: text/xml Headers: {SOAPAction=[""], Authorization=[Basic cWFfc3VwZXI6cWFfc3VwZXI=], Accept=[*/*]} Payload: <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"><soap:Body><ns1:findContacts>...bunch of xml deleted for brevity...</ns1:findContacts></soap:Body></soap:Envelope> -------------------------------------- May 17, 2010 3:23:45 PM org.apache.cxf.interceptor.LoggingInInterceptor logging INFO: Inbound Message ---------------------------- ID: 1 Response-Code: 200 Encoding: UTF-8 Content-Type: text/xml; charset=utf-8 Headers: {content-type=[text/xml; charset=utf-8], Content-Length=[611], Server=[Jetty(6.1.x)]} Payload: <soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/"><soap:Body><ns1:findContactsResponse>...bunch of xml spew deleted for brevity...</ns1:findContactsResponse></soap:Body></soap:Envelope> -------------------------------------- Any ideas what I'm doing wrong? Even if the server wasn't supporting FastInfoset, I still should see the attempted negotiation in the request, right?

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  • XForms relation of 'constraint' and 'required' properties

    - by Danny
    As a reference, the most similar question already asked is: http://stackoverflow.com/questions/8667849/making-xforms-enforce-the-constraint-and-type-model-item-properties-only-when-fi The difference is that I cannot use the relevant properties since I do want the field to be visible and accessible. I'm attempting to make a XForms form that has the following properties: It displays a text field named 'information'. (for the example) This field must not be required, since it may not be necessary to enter data. (Or this data will be entered at a later time.) However, if data is entered in this field, it must adhere to the specified constraint. I cannot mark the field as not relevant since this would hide the field and some data may need to be entered in it. The trouble now is that even though the field has no data in it, the constraint is still enforced (i.e. even though it is not marked as 'required'). I have taken a look at the XForms 1.1 specification, however it does not seem to describe how the properties 'required' and 'constraint' should interact. The only option I see, is to add a part to the constraint such that an empty value is allowed. e.g.: . = '' or <actual-constraint However, I don't like this. It feels like a workaround to add this to every such field. Is there any other way to express that non-required fields should not need to match the constraint for that field? (Am I missing something?)

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  • Would an immutable keyword in Java be a good idea?

    - by berry120
    Generally speaking, the more I use immutable objects in Java the more I'm thinking they're a great idea. They've got lots of advantages from automatically being thread-safe to not needing to worry about cloning or copy constructors. This has got me thinking, would an "immutable" keyword go amiss? Obviously there's the disadvantages with adding another reserved word to the language, and I doubt it will actually happen primarily for the above reason - but ignoring that I can't really see many disadvantages. At present great care has to be taken to make sure objects are immutable, and even then a dodgy javadoc comment claiming a component object is immutable when it's in fact not can wreck the whole thing. There's also the argument that even basic objects like string aren't truly immutable because they're easily vunerable to reflection attacks. If we had an immutable keyword the compiler could surely recursively check and give an iron clad guarantee that all instances of a class were immutable, something that can't presently be done. Especially with concurrency becoming more and more used, I personally think it'd be good to add a keyword to this effect. But are there any disadvantages or implementation details I'm missing that makes this a bad idea?

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  • Why is PHP discriminating between .php and .abc extensions for caching?

    - by Sam
    There seems to be a problem between how PHP engine handles identical files that differ only in their file extension. Problem: "An If-Modified-Since conditional request returned the full content unchanged." Also, I measured that the .php extension loads much faster than identitcal twin with .xxx extension even though the file contents are identical, and they differ only in their file extension. "HTTP allows clients to make conditional requests to see if a copy that they hold is still valid. Since this response has a Last-Modified header, clients should be able to use an If-Modified-Since request header for validation. RED has done this and found that the resource sends a full response even though it hadn't changed, indicating that it doesn't support Last-Modified validation." homepage ending with .php exact same file, but ending .ast Given: A home.php file is copied as home.xxx and this extension is added to htaccess to recognize it as a PHP file. The .php file listen to the php.ini where freshness is set to 3 hrs, the non .php files have to listen to htaccess where freshness is set to 2 hrs according to: AddType application/x-httpd-php .php .ast .abc .xxx .etc <IfModule mod_headers.c> ExpiresActive On ExpiresDefault M2419200 Header unset ETag FileETag None Header unset Pragma Header set Cache-Control "max-age=2419200" ##### DYNAMIC PAGES <FilesMatch "\\.(ast|php|abc|xxx)$"> ExpiresDefault M7200 Header set Cache-Control "public, max-age=7200" </FilesMatch> </IfModule> So far so good and everything loads, except, the non-php file doesn't cache properly, or it does cache well but doesn't validate well, to be more specific. See images enclosed. Only the non-php file extension causes the error and loads slower. The entire page.php loads faster as somehow all the elements in there then load properly from cache, while the page.abc has the full request returned while it ought to be cached, meaning the entire page is slower. Bottom line: What should be changed, in order eliminate the If-Modified-Since conditional request returning the full content unchanged?

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  • Common "truisms" needing correction the most

    - by Charles Bretana
    In addition to "I never met a man I didn't like", Will Rogers had another great little ditty I've always remembered. It went: "It's not what you don't know that'll hurt you, it's what you do know that ain't so." We all know or subscribe to many IT "truisms" that mostly have a strong basis in fact, in something in our professional careers, something we learned from others, lessons learned the hard way by ourselves, or by others who came before us. Unfortuntely, as these truisms spread throughout the community, the details—why they came about and the caveats that affect when they apply—tend to not spread along with them. We all have a tendency to look for, and latch on to, small "rules" or principles that we can use to avoid doing a complete exhaustive analysis for every decision. But even though they are correct much of the time, when we sometimes misapply them, we pay a penalty that could be avoided by understooding the details behind them. For example, when user-defined functions were first introduced in SQL Server it became "common knowledge" within a year or so that they had extremely bad performance (because it required a re-compilation for each use) and should be avoided. This "trusim" still increases many database developers' aversion to using UDFs, even though Microsoft's introduction of InLine UDFs, which do not suffer from this issue at all, mitigates this issue substantially. In recent years I have run into numerous DBAs who still believe you should "never" use UDFs, because of this. What other common not-so-"trusims" do you know, which many developers believe, that are not quite as universally true as is commonly understood, and which the developer community would benefit from being better educated about? Please include why it was "true" to start off with, and under what circumstances it's not true. Limit responses to issues that are technical, where the "common" application of a "rule or principle" is in fact correct most of the time, or was correct back when it was first elucidated, but—in the edge cases, or because of not understanding the principle thoroughly, because technology has changed since it first spread, or applying the rule today without understanding the details behind the rule—can easily backfire or cause the opposite of the intended effect.

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  • How to find out where a thread lock happend?

    - by SchlaWiener
    One of our company's Windows Forms application had a strange problem for several month. The app worked very reliable for most of our customers but on some PC's (mostly with a wireless lan connection) the app sometimes just didn't respond anymore. (You click on the UI and windows ask you to wait or kill the app). I wasn't able to track down the problem for a long time but now I figured out what happend. The app had this line of code // don't blame me for this. Wasn't my code :D Control.CheckForIllegalCrossThreadCalls = false and used some background threads to modify the controls. No I found a way to reproduce the application stopping responding bug on my dev machine and tracked it down to a line where I actually used Invoke() to run a task in the main thread. Me.Invoke(MyDelegate, arg1, arg2) Obviously there was a thread lock somewhere. After removing the Control.CheckForIllegalCrossThreadCalls = false statement and refactoring the whole programm to use Invoke() if modifying a control from a background thread, the problem is (hopefully) gone. However, I am wondering if there is a way to find such bugs without debugging every line of code (Even if I break into debugger after the app stops responding I can't tell what happend last, because the IDE didn't jump to the Invoke() statement) In other words: If my apps hangs how can I figure out which line of code has been executed last? Maybe even on the customers PC. I know VS2010 offers some backwards debugging feature, maybe that would be a solution, but currently I am using VS2008.

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  • Building "isolated" and "automatically updated" caches (java.util.List) in Java.

    - by Aidos
    Hi Guys, I am trying to write a framework which contains a lot of short-lived caches created from a long-living cache. These short-lived caches need to be able to return their entier contents, which is a clone from the original long-living cache. Effectively what I am trying to build is a level of transaction isolation for the short-lived caches. The user should be able to modify the contents of the short-lived cache, but changes to the long-living cache should not be propogated through (there is also a case where the changes should be pushed through, depending on the Cache type). I will do my best to try and explain: master-cache contains: [A,B,C,D,E,F] temporary-cache created with state [A,B,C,D,E,F] 1) temporary-cache adds item G: [A,B,C,D,E,F] 2) temporary-cache removes item B: [A,C,D,E,F] master-cache contains: [A,B,C,D,E,F] 3) master-cache adds items [X,Y,Z]: [A,B,C,D,E,F,X,Y,Z] temporary-cache contains: [A,C,D,E,F] Things get even harder when the values in the items can change and shouldn't always be updated (so I can't even share the underlying object instances, I need to use clones). I have implemented the simple approach of just creating a new instance of the List using the standard Collection constructor on ArrayList, however when you get out to about 200,000 items the system just runs out of memory. I know the value of 200,000 is excessive to iterate, but I am trying to stress my code a bit. I had thought that it might be able to somehow "proxy" the list, so the temporary-cache uses the master-cache, and stores all of it's changes (effectively a Memento for the change), however that quickly becomes a nightmare when you want to iterate the temporary-cache, or retrieve an item at a specific index. Also given that I want some modifications to the contents of the list to come through (depending on the type of the temporary-cache, whether it is "auto-update" or not) and I get completly out of my depth. Any pointers to techniques or data-structures or just general concepts to try and research will be greatly appreciated. Cheers, Aidos

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