Search Results

Search found 14182 results on 568 pages for 'andrew answer'.

Page 554/568 | < Previous Page | 550 551 552 553 554 555 556 557 558 559 560 561  | Next Page >

• Is this a right way to use NHibernate?

  - by Venemo

  I spent the rest of the evening reading StackOverflow questions and also some blog entries and links about the subject. All of them turned out to be very helpful, but I still feel that they don't really answer my question. So, I'm developing a simple web application. I'd like to create a reusable data access layer which I can later reuse in other solutions. 99% of these will be web applications. This seems to be a good excuse for me to learn NHibernate and some of the patterns around it. My goals are the following: I don't want the business logic layer to know ANYTHING about the inner workings of the database, nor NHibernate itself. I want the business logic layer to have the least possible number of assumptions about the data access layer. I want the data access layer as simplistic and easy-to-use as possible. This is going to be a simple project, so I don't want to overcomplicate anything. I want the data access layer to be as non-intrusive as possible. Will all this in mind, I decided to use the popular repository pattern. I read about this subject on this site and on various dev blogs, and I heard some stuff about the unit of work pattern. I also looked around and checked out various implementations. (Including FubuMVC contrib, and SharpArchitecture, and stuff on some blogs.) I found out that most of these operate with the same principle: They create a "unit of work" which is instantiated when a repository is instantiated, they start a transaction, do stuff, and commit, and then start all over again. So, only one ISession per Repository and that's it. Then the client code needs to instantiate a repository, do stuff with it, and then dispose. This usage pattern doesn't meet my need of being as simplistic as possible, so I began thinking about something else. I found out that NHibernate already has something which makes custom "unit of work" implementations unnecessary, and that is the CurrentSessionContext class. If I configure the session context correctly, and do the clean up when necessary, I'm good to go. So, I came up with this: I have a static class called NHibernateHelper. Firstly, it has a static property called CurrentSessionFactory, which upon first call, instantiates a session factory and stores it in a static field. (One ISessionFactory per one AppDomain is good enough.) Then, more importantly, it has a CurrentSession static property, which checks if there is an ISession bound to the current session context, and if not, creates one, and binds it, and it returns with the ISession bound to the current session context. Because it will be used mostly with WebSessionContext (so, one ISession per HttpRequest, although for the unit tests, I configured ThreadStaticSessionContext), it should work seamlessly. And after creating and binding an ISession, it hooks an event handler to the HttpContext.Current.ApplicationInstance.EndRequest event, which takes care of cleaning up the ISession after the request ends. (Of course, it only does this if it is really running in a web environment.) So, with all this set up, the NHibernateHelper will always be able to return a valid ISession, so there is no need to instantiate a Repository instance for the "unit of work" to operate properly. Instead, the Repository is a static class which operates with the ISession from the NHibernateHelper.CurrentSession property, and exposes some functionality through that. I'm curious, what do you think about this? Is it a valid way of thinking, or am I completely off track here?

  Read the article

• Constructing a Binary Tree from its traversals

  - by user991710

  I'm trying to construct a binary tree (unbalanced), given its traversals. I'm currently doing preorder + inorder but when I figure this out postorder will be no issue at all. I realize there are some question on the topic already but none of them seemed to answer my question. I've got a recursive method that takes the Preorder and the Inorder of a binary tree to reconstruct it, but is for some reason failing to link the root node with the subsequent children. Note: I don't want a solution. I've been trying to figure this out for a few hours now and even jotted down the recursion on paper and everything seems fine... so I must be missing something subtle. Here's the code: public static <T> BinaryNode<T> prePlusIn( T[] pre, T[] in) { if(pre.length != in.length) throw new IllegalArgumentException(); BinaryNode<T> base = new BinaryNode(); base.element = pre[0]; // * Get root from the preorder traversal. int indexOfRoot = 0; if(pre.length == 0 && in.length == 0) return null; if(pre.length == 1 && in.length == 1 && pre[0].equals(in[0])) return base; // * If both arrays are of size 1, element is a leaf. for(int i = 0; i < in.length -1; i++){ if(in[i].equals(base.element)){ // * Get the index of the root indexOfRoot = i; // in the inorder traversal. break; } // * If we cannot, the tree cannot be constructed as the traversals differ. else throw new IllegalArgumentException(); } // * Now, we recursively set the left and right subtrees of // the above "base" root node to whatever the new preorder // and inorder traversals end up constructing. T[] preleft = Arrays.copyOfRange(pre, 1, indexOfRoot + 1); T[] preright = Arrays.copyOfRange(pre, indexOfRoot + 1, pre.length); T[] inleft = Arrays.copyOfRange(in, 0, indexOfRoot); T[] inright = Arrays.copyOfRange(in, indexOfRoot + 1, in.length); base.left = prePlusIn( preleft, inleft); // * Construct left subtree. base.right = prePlusIn( preright, inright); // * Construc right subtree. return base; // * Return fully constructed tree } Basically, I construct additional arrays that house the pre- and inorder traversals of the left and right subtree (this seems terribly inefficient but I could not think of a better way with no helpers methods). Any ideas would be quite appreciated. Side note: While debugging it seems that the root note never receives the connections to the additional nodes (they remain null). From what I can see though, that should not happen... EDIT: To clarify, the method is throwing the IllegalArgumentException @ line 21 (else branch of the for loop, which should only be thrown if the traversals contain different elements.

  Read the article

• Did I find a bug in PHP's `crypt()`?

  - by Nathan Long

  I think I may have found a bug in PHP's crypt() function under Windows. However: I recognize that it's probably my fault. PHP is used by millions and worked on by thousands; my code is used by tens and worked on by me. (This argument is best explained on Coding Horror.) So I'm asking for help: show me my fault. I've been trying to find it for a few days now, with no luck. The setup I'm using a Windows server installation with Apache 2.2.14 (Win32) and PHP 5.3.2. My development box runs Windows XP Professional; the 'production' server (this is an intranet setup) runs Windows Storage Server 2003. The problem happens on both. I don't see anything in php.ini related to crypt(), but will happily answer questions about my config. The problem Several scripts in my PHP app occasionally hang: the page sits there on 'waiting for localhost' and never finishes. Each of these scripts uses crypt to hash a user's password before storing it in the database, or, in the case of the login page, to hash the entered password before comparing it to the version stored in the database. Since the login page is the simplest, I focused on it for testing. I repeatedly logged in, and found that it would hang maybe 4 out of 10 times. As an experiment, I changed the login page to use the plain text password and changed my password in the database to its plain text version. The page stopped hanging. I saw that PHP's latest version lists this bugfix: Fixed bug #51059 (crypt crashes when invalid salt are [sic] given). So I created a very simple test script, as follows, using the same salt given in an official example: $foo = crypt('rasmuslerdorf','r1'); echo $foo; This page, too, will hang, if I reload it like crazy. I only see it hanging in Chrome, but regardless of browser, the effect on Apache is the same. Effect on Apache When these pages hang, Apache's server-status page (which I explained here, regarding a different problem) increments the number of requests being processed and decrements the number of idle workers. The requests being processed almost all have a status of 'Sending Reply,' though sometimes for a moment they will show either 'Reading request' or 'keepalive (read).' Eventually, Apache may crash. When it does, the Windows crash report looks like this: szAppName: httpd.exe szAppVer: 2.2.14.0 szModName: php5ts.dll szModVer: 5.3.1.0 // OK, this report was before I upgraded to PHP 5.3.2, // but that didn't fix it offset: 00a2615 Is it my fault? I'm tempted to file a bug report to PHP on this. The argument against it is, as stated above, that bugs are nearly always my fault. However, my argument in favor of 'it's PHP's fault' is: I'm using Windows, whereas most servers use Linux (I don't get to choose this), so the chances are greater that I've found an edge case There was recently a bug with crypt(), so maybe it still has issues I have made the simplest test case I can, and I still have the problem Can anyone duplicate this? Can you suggest where I've gone wrong? Should I file the bug after all? Thanks in advance for any help you may give.

  Read the article

• Warning: comparison with string literals results in unspecified behaviour

  - by nunos

  So I starting the project of writing a simplified sheel for linux in c. I am not at all proficient with c nor with Linux that's exactly the reason I decided it would be a good idea. Starting with the parser, I have already encountered some problems. The code should be straightforward that's why I didn't include any comments. I am getting a warning with gcc: "comparison with string literals results in unspecified behaviour" at the lines commented with "WARNING HERE" (see code below). I have no idea why this causes an warning, but the real problem is that even though I am comparing an "<" to an "<" is doesn't get inside the if... I am looking for an answer for the problem explained, however if there's something that you see in the code that should be improved please say so. Just take in mind I am not that proficient and that this is still a work in progress (or better yet, a work in start). Thanks in advance. #include <stdio.h> #include <unistd.h> #include <string.h> typedef enum {false, true} bool; typedef struct { char **arg; char *infile; char *outfile; int background; } Command_Info; int parse_cmd(char *cmd_line, Command_Info *cmd_info) { char *arg; char *args[100]; int i = 0; arg = strtok(cmd_line, " \n"); while (arg != NULL) { args[i] = arg; arg = strtok(NULL, " \n"); i++; } int num_elems = i; cmd_info->infile = NULL; cmd_info->outfile = NULL; cmd_info->background = 0; int iarg = 0; for (i = 0; i < num_elems; i++) { if (args[i] == "&") //WARNING HERE return -1; else if (args[i] == "<") //WARNING HERE if (args[i+1] != NULL) cmd_info->infile = args[i+1]; else return -1; else if (args[i] == ">") //WARNING HERE if (args[i+1] != NULL) cmd_info->outfile = args[i+1]; else return -1; else cmd_info->arg[iarg++] = args[i]; } cmd_info->arg[iarg] = NULL; return 0; } void print_cmd(Command_Info *cmd_info) { int i; for (i = 0; cmd_info->arg[i] != NULL; i++) printf("arg[%d]=\"%s\"\n", i, cmd_info->arg[i]); printf("arg[%d]=\"%s\"\n", i, cmd_info->arg[i]); printf("infile=\"%s\"\n", cmd_info->infile); printf("outfile=\"%s\"\n", cmd_info->outfile); printf("background=\"%d\"\n", cmd_info->background); } int main(int argc, char* argv[]) { char cmd_line[100]; Command_Info cmd_info; printf(">>> "); fgets(cmd_line, 100, stdin); parse_cmd(cmd_line, &cmd_info); print_cmd(&cmd_info); return 0; }

  Read the article

• Get mutually and non mutually existening Fields in same table in Two columns

  - by ranabra

  This is a question similar to another question I posted here but is a little different. I am trying to get a list of all instances of mutual and non-mutual existing Users. What I mean is that the returned result from the query will return a list of users along with their co-worker. It is similar to the question here, but the difference is that non mutual users will be returned too and with out the "duplicity" mutually existing users return in the list (See image below in-order simplify it all). I took the original answer from Thomas (Thanx again Thomas) Select D1.u_username, U1.Permission, U1.Grade, D1.f_username, U2.Permission, U2.Gradefrom tblDynamicUserList As D1    Join tblDynamicUserList As D2        On D2.u_username = D1.f_username            And D2.f_username = D1.u_username    Join tblUsers As U1        On U1.u_username = D1.u_username    Join tblUsers As U2        On U2.u_username = D2.u_username and after some several trials I commented out 2 lines (Below). The returned result are exactly as described in the beginning of this question, but with the "duplicity" returned by mutually existing users in the table. How can I eliminate this duplicity? Select D1.u_username, U1.Permission, U1.Grade, D1.f_username, U2.Permission, U2.Gradefrom tblDynamicUserList As D1    Join tblDynamicUserList As D2        On D2.u_username = D1.f_username            /* And D2.f_username = D1.u_username */    Join tblUsers As U1        On U1.u_username = D1.u_username    Join tblUsers As U2        On U2.u_username = D2.u_username /* WHERE D1.U_userName < D1.f_username */ *Screenshot that hopefully helps explain it all. Database is SQL 2005. Many thanx in advance

  Read the article

• What container type provides better (average) performance than std::map?

  - by Truncheon

  In the following example a std::map structure is filled with 26 values from A - Z (for key) and 0 - 26 for value. The time taken (on my system) to lookup the last entry (10000000 times) is roughly 250 ms for the vector, and 125 ms for the map. (I compiled using release mode, with O3 option turned on for g++ 4.4) But if for some odd reason I wanted better performance than the std::map, what data structures and functions would I need to consider using? I apologize if the answer seems obvious to you, but I haven't had much experience in the performance critical aspects of C++ programming. UPDATE: This example is rather trivial and hides the true complexity of what I'm trying to achieve. My real world project is a simple scripting language that uses a parser, data tree, and interpreter (instead of a VM stack system). I need to use some kind of data structure (perhaps map) to store the variables names created by script programmers. These are likely to be pretty randomly named, so I need a lookup method that can quickly find a particular key within a (probably) fairly large list of names. #include <ctime> #include <map> #include <vector> #include <iostream> struct mystruct { char key; int value; mystruct(char k = 0, int v = 0) : key(k), value(v) { } }; int find(const std::vector<mystruct>& ref, char key) { for (std::vector<mystruct>::const_iterator i = ref.begin(); i != ref.end(); ++i) if (i->key == key) return i->value; return -1; } int main() { std::map<char, int> mymap; std::vector<mystruct> myvec; for (int i = 'a'; i < 'a' + 26; ++i) { mymap[i] = i - 'a'; myvec.push_back(mystruct(i, i - 'a')); } int pre = clock(); for (int i = 0; i < 10000000; ++i) { find(myvec, 'z'); } std::cout << "linear scan: milli " << clock() - pre << "\n"; pre = clock(); for (int i = 0; i < 10000000; ++i) { mymap['z']; } std::cout << "map scan: milli " << clock() - pre << "\n"; return 0; }

  Read the article

• Help with this code.

  - by karthick6891

  Heading ##Hey guys i need help with this code.The short version is,i have to do match the follwing by using drag and drop in jquery and later i need to show a message whether it is right or wrong. var output = "Wrong"; var old_item ; var new_item ; var newObjArray=[]; $(function() { var $gallery = $('.gallery'), $trash = $('.trash'); $('div',$gallery).draggable({ revert: 'invalid', containment: 'document', helper: 'clone', cursor: 'move', }); // let the trash be droppable, accepting the gallery items $trash.droppable({ //accept: '#gallery div', //activeClass: 'ui-state-highlight', tolerance: 'touch', drop: function(ev, ui) { new_item = ui.draggable; $(this).droppable("option","activeClass",'.ui-state-highlight'); if(contains(newObjArray,ui.draggable)) { newObjArray.pop(ui.draggable); } newObjArray.push(ui.draggable); deleteImage(ui.draggable,$(this)); } }); // let the gallery be droppable as well, accepting items from the trash $gallery.droppable({ //accept: '#trash li', activeClass: 'custom-state-active', drop: function(ev, ui) { recycleImage(ui.draggable); } }); // image deletion function function deleteImage($item,element) { var $list; $item.fadeOut(10,function() { if($(".ui-widget-content", element).length <1){ old_item = $item; $list = $('<div class="gallery ui-helper-reset"/>').appendTo(element); //$('ul',$trash).length ? $('ul',$trash) : $('<ul class="gallery ui-helper-reset"/>').appendTo($trash); $item.appendTo($list).fadeIn(10); } else{ recycleImage($(".ui-widget-content",element)); $list = $('<div class="gallery ui-helper-reset"/>').appendTo(element); $item.appendTo($list).fadeIn(10); old_item = $item; } }); } //check for given answer // image recycle function function recycleImage($item) { $item.fadeOut(10,function() { $item.find("img").end().appendTo($gallery).fadeIn(10); }); } // image preview function, demonstrating the ui.dialog used as a modal window }); function checkOrder(){ if(newObjArray==null){ } else if(newObjArray!=null){ if(newObjArray[0].attr("id")=="5"&& newObjArray[1].attr("id")=="1" && newObjArray[2].attr("id")=="3" && newObjArray[3].attr("id")=="2" && newObjArray[4].attr("id")=="4"){ parent.parent.increaseCorrectA(); } else{ parent.parent.increaseWrongA(); } } } function contains(a, obj) { var i = a.length; while (i--) { if (a[i] === obj) { return true; } } return false; } I am calling the function checkOrder() from the html page after the matching of items is over.What happens here is i have just stored the user responses on the draggable over droppable in an array,based on it's position.It is a bad practice cause,i am saying whether it's right or wrong through its position in the array.The only thing i can do is get the draggable's id present in the droppable.But i dont know how to get that inside the function checkOrder().Any ideas please?

  Read the article

• ASP.NET MVC 3 embrace dynamic type - CSDN.NET - CSDN Software Development Channel

  - by user559071

  About a decade ago, Microsoft will all bet on the WebForms and static types. With the complete package from scattered to the continuous development, and now almost every page can be viewed as its own procedure. Subsequent years, the industry continued to move in another direction, love is better than separation package, better than the late binding early binding to the idea. This leads to two very interesting questions. The first is the problem of terminology. Consider the original Smalltalk MVC model, view and controller is not only tightly coupled together, and usually in pairs. Most of the framework is that Microsoft, including the classic VB, WinForms, WebForms, WPF and Silverlight, they both use the code behind file to store the controller logic. But said "MVC" usually refers to the view and controller are loosely coupled framework. This is especially true for the Web framework, HTML form submission mechanism allows any views submitted to any of the controller. Since this article was mainly talking about Web technologies, so we need to use the modern definition. The second question is "If you're Microsoft, how to change orbit without causing too much pressure to the developer?" So far, the answer is: new releases each year, until the developers meet up. ASP.NET MVC's first product was released last March. Released in March this year, ASP.NET MVC 2.0. 3.0 RC 2 is currently in phase, expected to be released next March. December 10, Microsoft released ASP.NET MVC 3.0 Release Candidate 2. RC 2 is built on top of Microsoft's commitment to the jQuery: The default project template into jQuery 1.4.4, jQuery Validation 1.7 and jQuery UI. Although people think that Microsoft will focus shifted away from server-side controls to be a joke, but the introduction of Microsoft's jQuery UI is that this is the real thing. For those worried about the scalability of the developers, there are many excellent control can replace the session state. With SessionState property, you can tell the controller session state is read-only, read-write, or can be completely ignored in the. This site is no single server, but if a server needs to access another server session state, then this approach can provide a great help. MVC 3 contains Razor view engine. By default, the engine will be encoded HTML output, so that we can easily output on the screen the text of the original. HTML injection attacks even without the risk of encoded text can not easily prevent the page rendering. For many C # developers in the end do what is most shocking that MVC 3 for the controller and view and embrace the dynamic type. ViewBag property will open a dynamic object, developers can run on top of the object to add attributes. In general, it is used to send the view from the controller non-mode data. Scott Guthrie provides state of the sample contains text (such as the current time) and used to assemble the list box entries. Asked Link: http://www.infoq.com/cn/news/2010/12/ASPNET-MVC-3-RC-2; jsessionid = 3561C3B7957F1FB97848950809AD9483

  Read the article

• Recommended integration mechanism for bi-directional, authenticated, encrypted connection in C clien

  - by rcampbell

  Let me first give an example. Imagine you have a single server running a JVM application. This server keeps a collection of N equations, once for each client: Client #1: 2x Client #2: 1 + y Client #3: z/4 This server includes an HTTP interface so that random visitors can type https://www.acme.com/client/3 int their browsers and see the latest evaluated result of z/4. The tricky part is that either the client or the server may change the variable value at any time, informing the other party immediately. More specifically, Client #3 - a C app - can initially tell the server that z = 20. An hour later that same client informs the server that z = 23. Likewise the server can later inform the client that z = 28. As caf pointed out in the comments, there can be a race condition when values are changed by the client and server simultaneously. The solution would be for both client and server to send the operation performed in their message, which would need to be executed by the other party. To keep things simple, let's limit the operations to (commutative) addition, allowing us to disregard message ordering. For example, the client seeds the server with z = 20: server:z=20, client:z=20 server sends {+3} message (so z=23 locally) & client sends {-2} message (so z=18 locally) at the exact same time server receives {-2} message at some point, adds to his local copy so z=21 client receives {+3} message at some point, adds to his local copy so z=21 As long as all messages are eventually evaluated by both parties, the correct answer will eventually be given to the users of the client and server since we limited ourselves to commutative operations (addition of 3 and -2). This does mean that both client and server can be returning incorrect answers in the time it takes for messages to be exchanged and processed. While undesirable, I believe this is unavoidable. Some possible implementations of this idea include: Open an encrypted, always on TCP socket connection for communication Pros: no additional infrastructure needed, client and server know immediately if there is a problem (disconnect) with the other party, fairly straightforward (except the the encryption), native support from both JVM and C platforms Cons: pretty low-level so you end up writing a lot yourself (protocol, delivery verification, retry-on-failure logic), probably have a lot of firewall headaches during client app installation Asynchronous messaging (ex: ActiveMQ) Pros: transactional, both C & Java integration, free up the client and server apps from needing retry logic or delivery verification, pretty straightforward encryption, easy extensibility via message filters/routers/etc Cons: need additional infrastructure (message server) which must never fail, Database or file system as asynchronous integration point Same pros/cons as above but messier RESTful Web Service Pros: simple, possible reuse of the server's existing REST API, SSL figures out the encryption problem for you (maybe use RSA key a la GitHub for authentication?) Cons: Client now needs to run a C HTTP REST server w/SSL, client and server need retry logic. Axis2 has both a Java and C version, but you may be limited to SOAP. What other techniques should I be evaluating? What real world experiences have you had with these mechanisms? Which do you recommend for this problem and why?

  Read the article

• R: extracting "clean" UTF-8 text from a web page scraped with RCurl

  - by SlowLearner

  Using R, I am trying to scrape a web page save the text, which is in Japanese, to a file. Ultimately this needs to be scaled to tackle hundreds of pages on a daily basis. I already have a workable solution in Perl, but I am trying to migrate the script to R to reduce the cognitive load of switching between multiple languages. So far I am not succeeding. Related questions seem to be this one on saving csv files and this one on writing Hebrew to a HTML file. However, I haven't been successful in cobbling together a solution based on the answers there. The pages are from Yahoo! Japan Finance and my Perl code that looks like this. use strict; use HTML::Tree; use LWP::Simple; #use Encode; use utf8; binmode STDOUT, ":utf8"; my @arr_links = (); $arr_links[1] = "http://stocks.finance.yahoo.co.jp/stocks/detail/?code=7203"; $arr_links[2] = "http://stocks.finance.yahoo.co.jp/stocks/detail/?code=7201"; foreach my $link (@arr_links){ $link =~ s/"//gi; print("$link\n"); my $content = get($link); my $tree = HTML::Tree->new(); $tree->parse($content); my $bar = $tree->as_text; open OUTFILE, ">>:utf8", join("","c:/", substr($link, -4),"_perl.txt") || die; print OUTFILE $bar; } This Perl script produces a CSV file that looks like the screenshot below, with proper kanji and kana that can be mined and manipulated offline: My R code, such as it is, looks like the following. The R script is not an exact duplicate of the Perl solution just given, as it doesn't strip out the HTML and leave the text (this answer suggests an approach using R but it doesn't work for me in this case) and it doesn't have the loop and so on, but the intent is the same. require(RCurl) require(XML) links <- list() links[1] <- "http://stocks.finance.yahoo.co.jp/stocks/detail/?code=7203" links[2] <- "http://stocks.finance.yahoo.co.jp/stocks/detail/?code=7201" txt <- getURL(links, .encoding = "UTF-8") Encoding(txt) <- "bytes" write.table(txt, "c:/geturl_r.txt", quote = FALSE, row.names = FALSE, sep = "\t", fileEncoding = "UTF-8") This R script generates the output shown in the screenshot below. Basically rubbish. I assume that there is some combination of HTML, text and file encoding that will allow me to generate in R a similar result to that of the Perl solution but I cannot find it. The header of the HTML page I'm trying to scrape says the chartset is utf-8 and I have set the encoding in the getURL call and in the write.table function to utf-8, but this alone isn't enough. The question How can I scrape the above web page using R and save the text as CSV in "well-formed" Japanese text rather than something that looks like line noise? Edit: I have added a further screenshot to show what happens when I omit the Encoding step. I get what look like Unicode codes, but not the graphical representation of the characters. So it may be some kind of locale-related issue, but in the exact same locale the Perl script does provide useful output. So this is still puzzling.

  Read the article

• Detecting Acceleration in a car (iPhone Accelerometer)

  - by TheGazzardian

  Hello, I am working on an iPhone app where we are trying to calculate the acceleration of a moving car. Similar apps have accomplished this (Dynolicious), but the difference is that this app is designed to be used during general city driving, not on a drag strip. This leads us to one big concern that Dynolicious was luckily able to avoid: hills. Yes, hills. There are two important stages to this: calibration, and actual driving. Our initial run was simple and suffered the consequences. During the calibration stage, I took the average force on the phone, and during running, I just subtracted the average force from the current force to get the current acceleration this frame. The problem with this is that the typical car receives much more force than just the forward force - everything from turning to potholes was causing the values to go out of sync with what was really happening. The next run was to add the condition that the iPhone must be oriented in such a way that the screen was facing toward the back of the car. Using this method, I attempted to follow only force on the z-axis, but this obviously lead to problems unless the iPhone was oriented directly upright, because of gravity. Some trigonometry later, and I had managed to work gravity out of the equation, so that the car was actually being read very, very well by the iPhone. Until I hit a slope. As soon as the angle of the car changed, suddenly I was receiving accelerations and decelerations that didn't make sense, and we were once again going out of sync. Talking with someone a lot smarter than me at math lead to a solution that I have been trying to implement for longer than I would like to admit. It's steps are as follows: 1) During calibration, measure gravity as a vector instead of a size. Store that vector. 2) When the car initially moves forward, take the vector of motion and subtract gravity. Use this as the forward momentum. (Ignore, for now, the user cases where this will be difficult and let's concentrate on the math :) 3) From the forward vector and the gravity vector, construct a plane. 4) Whenever a force is received, project it onto said plane to get rid of sideways force/etc. 5) Then, use that force, the known magnitude of gravity, and the known direction of forward motion to essentially solve a triangle to get the forward vector. The problem that is causing the most difficulty in this new system is not step 5, which I have gotten to the point where all the numbers look as they should. The difficult part is actually the detection of the forward vector. I am selecting vectors whose magnitude exceeds gravity, and from there, averaging them and subtracting gravity. (I am doing some error checking to make sure that I am not using a force just because the iPhone accelerometer was off by a bit, which happens more frequently than I would like). But if I plot these vectors that I am using, they actually vary by an angle of about 20-30 degrees, which can lead to some strong inaccuracies. The end result is that the app is even more inaccurate now than before. So basically - all you math and iPhone brains out there - any glaring errors? Any potentially better solutions? Any experience that could be useful at all? Award: offering a bounty of $250 to the first answer that leads to a solution.

  Read the article

• Modern alternatives to Java

  - by Ralph

  I have been a Java developer for 14 years and have written an enterprise-level (~500 kloc) Swing application that uses most of the standard library APIs. Recently, I have become disappointed with the progress that the language has made to "modernize" itself, and am looking for an alternative for ongoing development. I have considered moving to the .NET platform, but I have issues with using something the only runs well in Windows (I know about Mono, but that is still far behind Microsoft). I also plan on buying a new Macbook Pro as soon as Apple releases their new rumored Arrandale-based machines and want to develop in an environment that will feel "at home" in Unix/Linux. I have considered using Python or Ruby, but the standard Java library is arguably the largest of any modern language. In JVM-based languages, I looked at Groovy, but am disappointed with its performance. Rumor has it that with the soon-to-be released JDK7, with its InvokeDynamic instruction, this will improve, but I don't know how much. Groovy is also not truly a functional language, although it provides closures and some of the "functional" features on collections. It does not embrace immutability. I have narrowed my search down to two JVM-based alternatives: Scala and Clojure. Each has its strengths and weaknesses. I am looking for opinions. I am not an expert at either of these languages; I have read 2 1/2 books on Scala and am currently reading Stu Halloway's book on Clojure. Scala is strongly statically typed. I know the dynamic language folks claim that static typing is a crutch for not doing unit testing, but it does provide a mechanism for compile-time location of a whole class of errors. Scala is more concise than Java, but not as much as Clojure. Scala's inter-operation with Java seems to be better than Clojure's, in that most Java operations are easier to do in Scala than in Clojure. For example, I can find no way in Clojure to create a non-static initialization block in a class derived from a Java superclass. For example, I like the Apache commons CLI library for command line argument parsing. In Java and Scala, I can create a new Options object and add Option items to it in an initialization block as follows (Java code): final Options options = new Options() { { addOption(new Option("?", "help", false, "Show this usage information"); // other options } }; I can't figure out how to the same thing in Clojure (except by using (doit...)), although that may reflect my lack of knowledge of the language. Clojure's collections are optimized for immutability. They rarely require copy-on-write semantics. I don't know if Scala's immutable collections are implemented using similar algorithms, but Rich Hickey (Clojure's inventor) goes out of his way to explain how that language's data structures are efficient. Clojure was designed from the beginning for concurrency (as was Scala) and with modern multi-core processors, concurrency takes on more importance, but I occasionally need to write simple non-concurrent utilities, and Scala code probably runs a little faster for these applications since it discourages, but does not prohibit, "simple" mutability. One could argue that one-off utilities do not have to be super-fast, but sometimes they do tasks that take hours or days to complete. I know that there is no right answer to this "question", but I thought I would open it up for discussion. Are there other JVM-based languages that can be used for enterprise level development?

  Read the article

• parallel computation for an Iterator of elements in Java

  - by Brian Harris

  I've had the same need a few times now and wanted to get other thoughts on the right way to structure a solution. The need is to perform some operation on many elements on many threads without needing to have all elements in memory at once, just the ones under computation. As in, Iterables.partition is insufficient because it brings all elements into memory up front. Expressing it in code, I want to write a BulkCalc2 that does the same thing as BulkCalc1, just in parallel. Below is sample code that illustrates my best attempt. I'm not satisfied because it's big and ugly, but it does seem to accomplish my goals of keeping threads highly utilized until the work is done, propagating any exceptions during computation, and not having more than numThreads instances of BigThing necessarily in memory at once. I'll accept the answer which meets the stated goals in the most concise way, whether it's a way to improve my BulkCalc2 or a completely different solution. interface BigThing { int getId(); String getString(); } class Calc { // somewhat expensive computation double calc(BigThing bigThing) { Random r = new Random(bigThing.getString().hashCode()); double d = 0; for (int i = 0; i < 100000; i++) { d += r.nextDouble(); } return d; } } class BulkCalc1 { final Calc calc; public BulkCalc1(Calc calc) { this.calc = calc; } public TreeMap<Integer, Double> calc(Iterator<BigThing> in) { TreeMap<Integer, Double> results = Maps.newTreeMap(); while (in.hasNext()) { BigThing o = in.next(); results.put(o.getId(), calc.calc(o)); } return results; } } class SafeIterator<T> { final Iterator<T> in; SafeIterator(Iterator<T> in) { this.in = in; } synchronized T nextOrNull() { if (in.hasNext()) { return in.next(); } return null; } } class BulkCalc2 { final Calc calc; final int numThreads; public BulkCalc2(Calc calc, int numThreads) { this.calc = calc; this.numThreads = numThreads; } public TreeMap<Integer, Double> calc(Iterator<BigThing> in) { ExecutorService e = Executors.newFixedThreadPool(numThreads); List<Future<?>> futures = Lists.newLinkedList(); final Map<Integer, Double> results = new MapMaker().concurrencyLevel(numThreads).makeMap(); final SafeIterator<BigThing> it = new SafeIterator<BigThing>(in); for (int i = 0; i < numThreads; i++) { futures.add(e.submit(new Runnable() { @Override public void run() { while (true) { BigThing o = it.nextOrNull(); if (o == null) { return; } results.put(o.getId(), calc.calc(o)); } } })); } e.shutdown(); for (Future<?> future : futures) { try { future.get(); } catch (InterruptedException ex) { // swallowing is OK } catch (ExecutionException ex) { throw Throwables.propagate(ex.getCause()); } } return new TreeMap<Integer, Double>(results); } }

  Read the article

• Game AI: Pattern for implementing Sense-Think-Act components?

  - by Rosarch

  I'm developing a game. Each entity in the game is a GameObject. Each GameObject is composed of a GameObjectController, GameObjectModel, and GameObjectView. (Or inheritants thereof.) For NPCs, the GameObjectController is split into: IThinkNPC: reads current state and makes a decision about what to do IActNPC: updates state based on what needs to be done ISenseNPC: reads current state to answer world queries (eg "am I being in the shadows?") My question: Is this ok for the ISenseNPC interface? public interface ISenseNPC { // ... /// <summary> /// True if `dest` is a safe point to which to retreat. /// </summary> /// <param name="dest"></param> /// <param name="angleToThreat"></param> /// <param name="range"></param> /// <returns></returns> bool IsSafeToRetreat(Vector2 dest, float angleToThreat, float range); /// <summary> /// Finds a new location to which to retreat. /// </summary> /// <param name="angleToThreat"></param> /// <returns></returns> Vector2 newRetreatDest(float angleToThreat); /// <summary> /// Returns the closest LightSource that illuminates the NPC. /// Null if the NPC is not illuminated. /// </summary> /// <returns></returns> ILightSource ClosestIlluminatingLight(); /// <summary> /// True if the NPC is sufficiently far away from target. /// Assumes that target is the only entity it could ever run from. /// </summary> /// <returns></returns> bool IsSafeFromTarget(); } None of the methods take any parameters. Instead, the implementation is expected to maintain a reference to the relevant GameObjectController and read that. However, I'm now trying to write unit tests for this. Obviously, it's necessary to use mocking, since I can't pass arguments directly. The way I'm doing it feels really brittle - what if another implementation comes along that uses the world query utilities in a different way? Really, I'm not testing the interface, I'm testing the implementation. Poor. The reason I used this pattern in the first place was to keep IThinkNPC implementation code clean: public BehaviorState RetreatTransition(BehaviorState currentBehavior) { if (sense.IsCollidingWithTarget()) { NPCUtils.TraceTransitionIfNeeded(ToString(), BehaviorState.ATTACK.ToString(), "is colliding with target"); return BehaviorState.ATTACK; } if (sense.IsSafeFromTarget() && sense.ClosestIlluminatingLight() == null) { return BehaviorState.WANDER; } if (sense.ClosestIlluminatingLight() != null && sense.SeesTarget()) { NPCUtils.TraceTransitionIfNeeded(ToString(), BehaviorState.ATTACK.ToString(), "collides with target"); return BehaviorState.CHASE; } return currentBehavior; } Perhaps the cleanliness isn't worth it, however. So, if ISenseNPC takes all the params it needs every time, I could make it static. Is there any problem with that?

  Read the article

• Facebook PHP SDK - will not logout properly

  - by garethdn

  I've been searching for hours for the solution to this problem but can't find one that works for me. When i click "Logout" on my site the user information is still visible and the logout button is still displayed. Here is the code: require 'facebook-php-sdk/src/facebook.php'; $facebook = new Facebook(array( 'appId' => 'xxxx', 'secret' => 'xxxx', )); // Get User ID $user = $facebook->getUser(); var_dump($user); if ($user) { try { // Proceed knowing you have a logged in user who's authenticated. $user_profile = $facebook->api('/me'); } catch (FacebookApiException $e) { error_log($e); $user = null; } } // Login or logout url will be needed depending on current user state. if ($_GET['logout'] == "yes") { setcookie('fbs_'.$facebook->getAppId(), '', time()-100, '/', 'http://gno.....ment/index.php'); session_destroy(); header("Location: ".$_SERVER['PHP_SELF'].""); } if ($user_profile) { $logoutUrl = $facebook->getLogoutUrl; } else { $loginUrl = $facebook->getLoginUrl(array('scope' => 'email,publish_stream,user_status', 'canvas' => 1, 'fbconnect' => 0, 'redirect_uri' => 'http://gno.....ment/index.php')); } ..... ..... <?php if ($user): ?> <h3>You</h3> <img src="https://graph.facebook.com/<?php echo $user; ?>/picture"> <h3>Your User Object (/me)</h3> <pre><?php print_r($user_profile); ?></pre> <?php else: ?> <strong><em>You are not Connected.</em></strong> <?php endif ?> <?php if ($user): ?> <a href="<?php echo $logoutUrl; ?>">Logout of FB</a> <?php else: ?> <div> Login using OAuth 2.0 handled by the PHP SDK: <a href="<?php echo $loginUrl; ?>">Login with Facebook</a> </div> <?php endif ?> It seems that if ($_GET['logout'] == "yes") might be the answer for me but i can't get it working. I don't know where logout is gotten from or where it is defined? This seems to be a common issue but i can't figure it out. I'd really appreciate some help.

  Read the article

• jQuery hold form submit until "continue" button pressed

  - by Seán McCabe

  I am trying to submit a form, which I have had working, but have now modified it to include a modal jQuery UI box, so that it won't submit until the user presses "continue". I've had various problems with this, including getting the form to hold until that button is pressed, but I think I have found a solution to that, but implementing it, I am getting a SyntaxError which I can't find the source of. With the help of kevin B managed to find the answer was the form was submitting, but the returned JSON response wasn't quite formatted right. The response was that the form wasn't being submitted, so that problem is still occurring. So updated the code with the provided feedback, now need to find out why the form isnt submitting. I know its something to do with the 2nd function isnt recognising the submit button has been pressed, so need to know how to submit that form data without the form needing to be submitted again. Below is the new code: function submitData() { $("#submitProvData").submit(function(event) { event.preventDefault(); var gTotal, sTotal, dfd; var dfd = new $.Deferred(); $('html,body').animate({ scrollTop: 0 }, 'fast'); $("#submitProvData input").css("border", "1px solid #aaaaaa"); $("#submitProvData input[readonly='readonly']").css("border", "none"); sTotal = $('#summaryTotal').val(); gTotal = $('#gptotal').val(); if(gTotal !== 'sTotal'){ $("#newsupinvbox").append('<div id="newsupinvdiagbox" title="Warning - Totals do not match" class="hidden"><p>Press "Continue", to submit the invoice flagged for attention.</p> <br /><p class="italic">or</p><br /> <p>Press "Correct" to correct the discrepancy.</p></div>') //CREATE DIV //SET $("#newsupinvdiagbox").dialog({ resizable: false, autoOpen:false, modal: true, draggable: false, width:380, height:240, closeOnEscape: false, position: ['center',20], buttons: { 'Continue': function() { $(this).dialog('close'); reData(); }, // end continue button 'Correct': function() { $(this).dialog('close'); return false; } //end cancel button }//end buttons });//end dialog $('#newsupinvdiagbox').dialog('open'); } return false; }); } function reData() { console.log('submitted'); $("#submitProvData").submit(function(resubmit){ console.log('form submit'); var formData; formData = new FormData($(this)[0]); $.ajax({ type: "POST", url: "functions/invoicing_upload_provider.php", data: formData, async: false, success: function(result) { $.each($.parseJSON(result), function(item, value){ if(item == 'Success'){ $('#newsupinv_window_message_success_mes').html('The provider invoice was uploaded successfully.'); $('#newsupinv_window_message_success').fadeIn(300, function (){ reset(); }).delay(2500).fadeOut(700); } else if(item == 'Error'){ $('#newsupinv_window_message_error_mes').html(value); $('#newsupinv_window_message_error').fadeIn(300).delay(3000).fadeOut(700); } else if(item == 'Warning'){ $('#newsupinv_window_message_warning_mes').html(value); $('#newsupinv_window_message_warning').fadeIn(300, function (){ reset(); }).delay(2500).fadeOut(700); } }); }, error: function() { $('#newsupinv_window_message_error_mes').html("An error occured, the form was not submitted"); $('#newsupinv_window_message_error').fadeIn(300); $('#newsupinv_window_message_error').delay(3000).fadeOut(700); }, cache: false, contentType: false, processData: false }); }); }

  Read the article

• What can I do to improve a project if there is a no-listening situation. Developers vs Management

  - by NazGul

  Hi all, I hope that I'm not the only one and I can get a answer from someone with more experience than me, so I can think cleaner and I don't get depressed with this developer's life. I'm working as developer for a small company three years now. In that three years I'm working in the same project and sincerely, I think this project could be used as a CASE STUDY because it has all the situations that cannot happen in a project and that makes a project fails. To begin with, and I believe you've already noticed, the project has 3 years already (develoment only) and is still unfinished, because in every meeting there is a "new priority" ,or a "new problem" to be solve or a "new feature" to be add. So, first problem is no target set. How can you know when something is finished if you don't know what you want? I understand Management, because they see an oportunity and try to get that, but I don't understand how can they not see (or hear us) that they'll lose all they already have and what they'll eventually get. Second, there is no team group. My team consists of three people, a Senior Developer, a DBA and, finally, I for all the work (support, testing, new features, bug fixing, meeting, projet management of clients, etc) aka Junior Developer. The first (senior developer), does not perform any tests on his changes, so, most of the time, his changes give us problems (us = me, since I'm the one who will fix it). The second (DBA) is an uncompromising person and you can not talk to him, believe me, I tried! In his view, everything he does is fantastic... even if it is the most complicated to make it... And he does everything he wants, even if we need that only for 5 months later and would help some extra-hand to do the things we have to do for now. As you can see, there is very hard to work with no help... Third, there is no testings. Every... I repeat, Every release of the project, the customers wants to kill us, because there is a lot of bugs. Management? They say that they want tests before the release. Us? We say the same. Time? No time. Management? There is always some time to open the application and click in some buttons. Us? Try to explain that it is not so simple. Management doesn't care... end of story. Actually, must of the bugs could be avoid with a rigorous work... Some people just want to do the show to the Management. "Did you ask for this? Cool, it's done. Bugs? The Do-all-the-work guy will solve." Unfortunally for me, sometimes the Do-all-the-work also has to finish it. And to makes this all better, I'm the person who will listen the complaints from the customers. Cool, huh? I know, everyone makes mistakes. But there is mistakes and mistakes... To complete, in the Management view, "the problem is the lack of an individual project management", because we cannot do all the stuff they ask, even if there is no PM for the project itself. And ask us to work overtime without any reward... I do say all this stuff to the management and others members, but by telling this, the I'm the bad guy, the guy who is complain when everything is going well... but we need to work overtime... sigh What can I do to make it works? Anyone has a situation like this, what did you do? I hope you could understand my problem, my English is a little rusty. Thanks.

  Read the article

• TypeError: Error #2007: Parameter child must be non-null.

  - by Bobby Francis Joseph

  I am running the following piece of code: package { import fl.controls.Button; import fl.controls.Label; import fl.controls.RadioButton; import fl.controls.RadioButtonGroup; import flash.display.Sprite; import flash.events.MouseEvent; import flash.text.TextFieldAutoSize; public class RadioButtonExample extends Sprite { private var j:uint; private var padding:uint = 10; private var currHeight:uint = 0; private var verticalSpacing:uint = 30; private var rbg:RadioButtonGroup; private var questionLabel:Label; private var answerLabel:Label; private var question:String = "What day is known internationally as Speak Like A Pirate Day?"; private var answers:Array = [ "August 12", "March 4", "September 19", "June 22" ]; public function RadioButtonExample() { setupQuiz(); } private function setupQuiz():void { setupQuestionLabel(); setupRadioButtons(); setupButton(); setupAnswerLabel(); } private function setupQuestionLabel():void { questionLabel = new Label(); questionLabel.text = question; questionLabel.autoSize = TextFieldAutoSize.LEFT; questionLabel.move(padding, padding + currHeight); currHeight += verticalSpacing; addChild(questionLabel); } private function setupAnswerLabel():void { answerLabel = new Label(); answerLabel.text = ""; answerLabel.autoSize = TextFieldAutoSize.LEFT; answerLabel.move(padding + 120, padding + currHeight); addChild(answerLabel); } private function setupRadioButtons():void { rbg = new RadioButtonGroup("question1"); createRadioButton(answers[0], rbg); createRadioButton(answers[1], rbg); createRadioButton(answers[2], rbg); createRadioButton(answers[3], rbg); } private function setupButton():void { var b:Button = new Button(); b.move(padding, padding + currHeight); b.label = "Check Answer"; b.addEventListener(MouseEvent.CLICK, checkAnswer); addChild(b); } private function createRadioButton(rbLabel:String, rbg:RadioButtonGroup):void { var rb:RadioButton = new RadioButton(); rb.group = rbg; rb.label = rbLabel; rb.move(padding, padding + currHeight); addChild(rb); currHeight += verticalSpacing; } private function checkAnswer(e:MouseEvent):void { if (rbg.selection == null) { return; } var resultStr:String = (rbg.selection.label == answers[2]) ? "Correct" : "Incorrect"; answerLabel.text = resultStr; } } } This is from Adobe Livedocs. http://www.adobe.com/livedocs/flash/9.0/ActionScriptLangRefV3/ I have added a Radiobutton to stage and then deleted it so that its there in the library. However I am getting the following error TypeError: Error #2007: Parameter child must be non-null. at flash.display::DisplayObjectContainer/addChildAt() at fl.controls::BaseButton/fl.controls:BaseButton::drawBackground() at fl.controls::LabelButton/fl.controls:LabelButton::draw() at fl.controls::Button/fl.controls:Button::draw() at fl.core::UIComponent/::callLaterDispatcher() Can anyone tell me what is going on and how to remove this error.

  Read the article

• What does the `forall` keyword in Haskell/GHC do?

  - by JUST MY correct OPINION

  I've been banging my head on this one for (quite literally) years now. I'm beginning to kinda/sorta understand how the foreach keyword is used in so-called "existential types" like this: data ShowBox = forall s. Show s => SB s (This despite the confusingly-worded explanations of it in the fragments found all around the web.) This is only a subset, however, of how foreach is used and I simply cannot wrap my mind around its use in things like this: runST :: forall a. (forall s. ST s a) -> a Or explaining why these are different: foo :: (forall a. a -> a) -> (Char,Bool) bar :: forall a. ((a -> a) -> (Char, Bool)) Or the whole RankNTypes stuff that breaks my brain when "explained" in a way that makes me want to do that Samuel L. Jackson thing from Pulp Fiction. (Don't follow that link if you're easily offended by strong language.) The problem, really, is that I'm a dullard. I can't fathom the chicken scratchings (some call them "formulae") of the elite mathematicians that created this language seeing as my university years are over two decades behind me and I never actually had to put what I learnt into use in practice. I also tend to prefer clear, jargon-free English rather than the kinds of language which are normal in academic environments. Most of the explanations I attempt to read on this (the ones I can find through search engines) have these problems: They're incomplete. They explain one part of the use of this keyword (like "existential types") which makes me feel happy until I read code that uses it in a completely different way (like runST, foo and bar above). They're densely packed with assumptions that I've read the latest in whatever branch of discrete math, category theory or abstract algebra is popular this week. (If I never read the words "consult the paper whatever for details of implementation" again, it will be too soon.) They're written in ways that frequently turn even simple concepts into tortuously twisted and fractured grammar and semantics. (I suspect that the last two items are the biggest problem. I wouldn't know, though, since I'm too much a dullard to comprehend them.) It's been asked why Haskell never really caught on in industry. I suspect, in my own humble, unintelligent way, that my experience in figuring out one stupid little keyword -- a keyword that is increasingly ubiquitous in the libraries being written these days -- are also part of the answer to that question. It's hard for a language to catch on when even its individual keywords cause years-long quests to comprehend. Years-long quests which end in failure. So... On to the actual question. Can anybody completely explain the foreach keyword in clear, plain English (or, if it exists somewhere, point to such a clear explanation which I've missed) that doesn't assume I'm a mathematician steeped in the jargon?

  Read the article

• Dispatcher Timer Problem

  - by will

  I am trying to make a game in silverlight that also has widgets in it. To do this I am using a dispatcher timer running a game loop that updates graphics etc. In this I have a variable that has to be accessed by both by the constantly running game loop and UI event code. At first look it seemed that the gameloop had its own local copy of currentUnit (the variable), despite the variable being declared globally. I am trying to update currentUnit with an event by the widget part of the app, but the timer's version of the variable is not being updated. What can I do get the currentUnit in the gameloop loop to be updated whenever I update currentUnit via a click event? Here is the code for setting currentUnit as part of a click event DataContractJsonSerializer serializer = new DataContractJsonSerializer(typeof(Unit)); currentUnit = serializer.ReadObject(e.Result) as Unit; txtName.Text = currentUnit.name; Canvas.SetLeft(txtName, 100 - (int)Math.Ceiling(txtName.ActualWidth) / 2); txtX.Text = "" + currentUnit.x; txtY.Text = "" + currentUnit.y; txtX.Text = "" + currentUnit.owner; txtY.Text = "" + currentUnit.moved; txtName.Text = "" + currentUnit.GetHashCode(); And here is a snippet from the gameLoop loop //deal with phase changes and showing stuff if (txtPhase.Text == "Move" && movementPanel.Visibility == Visibility.Collapsed) { if (currentUnit != null) { if (currentUnit.owner) { if (currentUnit.moved) { txtMoved.Text = "This Unit has Already Moved!"; movementPanel.Visibility = Visibility.Collapsed; } else { txtMoved.Text = "" + currentUnit.GetHashCode(); movementPanel.Visibility = Visibility.Visible; } } else { txtMoved.Text = "bam"; movementPanel.Visibility = Visibility.Collapsed; } } else { txtMoved.Text = "slam"; movementPanel.Visibility = Visibility.Collapsed; } //loadUnitList(); } Here is the code for my unit class. using System; public class Unit { public int id { get; set; } public string name { get; set; } public string image { get; set; } public int x { get; set; } public int y { get; set; } public bool owner { get; set; } public int rotation { get; set; } public double movement { get; set; } public string type { get; set; } public bool moved { get; set; } public bool fired { get; set; } } Overall, any simple types, like a double is being 'updated' correctly, yet a complex of my own type (Unit) seems to be holding a local copy. Please help, I've asked other places and no one has had an answer for me!

  Read the article

• C++: casting to void* and back

  - by MInner

  * ---Edit - now the whole sourse* When I debug it on the end, "get" and "value" have different values! Probably, I convert to void* and back to User the wrong way? #include <db_cxx.h> #include <stdio.h> struct User{ User(){} int name; int town; User(int a){}; inline int get_index(int a){ return town; } //for another stuff }; int main(){ try { DbEnv* env = new DbEnv(NULL); env->open("./", DB_CREATE | DB_INIT_MPOOL | DB_THREAD | DB_INIT_LOCK | DB_INIT_TXN | DB_RECOVER | DB_INIT_LOG, 0); Db* datab = new Db(env, 0); datab->open(NULL, "db.dbf", NULL, DB_BTREE, DB_CREATE | DB_AUTO_COMMIT, 0); Dbt key, value, get; char a[10] = "bbaaccd"; User u; u.name = 1; u.town = 34; key.set_data(a); key.set_size(strlen(a) + 1 ); value.set_data((void*)&u); value.set_size(sizeof(u)); get.set_flags(DB_DBT_MALLOC); DbTxn* txn; env->txn_begin(NULL, &txn, 0); datab->put(txn, &key, &value, 0); datab->get(txn, &key, &get, 0); txn->commit(0); User g; g = *((User*)&get); printf("%d", g.town); getchar(); return 0; }catch (DbException &e){ printf("%s", e.what()); getchar(); } solution create a kind of "serializator" what would convert all POD's into void* and then will unite these pieces PS Or I'd rewrite User into POD type and everything will be all right, I hope. Add It's strange, but... I cast a defenetly non-pod object to void* and back (it has std::string inside) and it's all right (without sending it to the db and back). How could it be? And after I cast and send 'trough' db defenetly pod object (no extra methods, all members are pod, it's a simple struct {int a; int b; ...}) I get back dirted one. What's wrong with my approach? Add about week after first 'add' Damn... I've compiled it ones, just for have a look at which kind of dirt it returnes, and oh! it's okay!... I can't ! ... AAh!.. Lord... A reasonable question (in 99.999 percent of situations right answer is 'my', but... here...) - whos is this fault? My or VSs?

  Read the article

• Do you have suggestions for these assembly mnemonics?

  - by Noctis Skytower

  Greetings! Last semester in college, my teacher in the Computer Languages class taught us the esoteric language named Whitespace. In the interest of learning the language better with a very busy schedule (midterms), I wrote an interpreter and assembler in Python. An assembly language was designed to facilitate writing programs easily, and a sample program was written with the given assembly mnemonics. Now that it is summer, a new project has begun with the objective being to rewrite the interpreter and assembler for Whitespace 0.3, with further developments coming afterwards. Since there is so much extra time than before to work on its design, you are presented here with an outline that provides a revised set of mnemonics for the assembly language. This post is marked as a wiki for their discussion. Have you ever had any experience with assembly languages in the past? Were there some instructions that you thought should have been renamed to something different? Did you find yourself thinking outside the box and with a different paradigm than in which the mnemonics were named? If you can answer yes to any of those questions, you are most welcome here. Subjective answers are appreciated! Stack Manipulation (IMP: [Space]) Stack manipulation is one of the more common operations, hence the shortness of the IMP [Space]. There are four stack instructions. hold N Push the number onto the stack copy Duplicate the top item on the stack copy N Copy the nth item on the stack (given by the argument) onto the top of the stack swap Swap the top two items on the stack drop Discard the top item on the stack drop N Slide n items off the stack, keeping the top item Arithmetic (IMP: [Tab][Space]) Arithmetic commands operate on the top two items on the stack, and replace them with the result of the operation. The first item pushed is considered to be left of the operator. add Addition sub Subtraction mul Multiplication div Integer Division mod Modulo Heap Access (IMP: [Tab][Tab]) Heap access commands look at the stack to find the address of items to be stored or retrieved. To store an item, push the address then the value and run the store command. To retrieve an item, push the address and run the retrieve command, which will place the value stored in the location at the top of the stack. save Store load Retrieve Flow Control (IMP: [LF]) Flow control operations are also common. Subroutines are marked by labels, as well as the targets of conditional and unconditional jumps, by which loops can be implemented. Programs must be ended by means of [LF][LF][LF] so that the interpreter can exit cleanly. L: Mark a location in the program call L Call a subroutine goto L Jump unconditionally to a label if=0 L Jump to a label if the top of the stack is zero if<0 L Jump to a label if the top of the stack is negative return End a subroutine and transfer control back to the caller halt End the program I/O (IMP: [Tab][LF]) Finally, we need to be able to interact with the user. There are IO instructions for reading and writing numbers and individual characters. With these, string manipulation routines can be written. The read instructions take the heap address in which to store the result from the top of the stack. print chr Output the character at the top of the stack print int Output the number at the top of the stack input chr Read a character and place it in the location given by the top of the stack input int Read a number and place it in the location given by the top of the stack Question: How would you redesign, rewrite, or rename the previous mnemonics and for what reasons?

  Read the article

• Simple Detached pThread does not cancel! (cout blocks and interleaves even if mutexed)

  - by Gabriel

  I have a hard problem here, which I can not solve and do not find the right answer on the net: I have created a detached thread with a clean up routing, the problem is that on my Imac and Ubuntu 9.1 (Dual Core). I am not able to correctly cancel the detached thread in the fallowing code: #include <iostream> #include <pthread.h> #include <sched.h> #include <signal.h> #include <time.h> pthread_mutex_t mutex_t; using namespace std; static void cleanup(void *arg){ pthread_mutex_lock(&mutex_t); cout << " doing clean up"<<endl; pthread_mutex_unlock(&mutex_t); } static void *thread(void *aArgument) { pthread_setcancelstate(PTHREAD_CANCEL_ENABLE,NULL); pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED,NULL); pthread_cleanup_push(&cleanup,NULL); int n=0; while(1){ pthread_testcancel(); sched_yield(); n++; pthread_mutex_lock(&mutex_t); cout << " Thread 2: "<< n<<endl; pthread_mutex_unlock(&mutex_t); } pthread_cleanup_pop(0); return NULL; } int main() { pthread_t thread_id; pthread_attr_t attr; pthread_attr_init(&attr); pthread_attr_setdetachstate(&attr,PTHREAD_CREATE_DETACHED); int error; if (pthread_mutex_init(&mutex_t,NULL) != 0) return 1; if (pthread_create(&thread_id, &attr, &(thread) , NULL) != 0) return 1; pthread_mutex_lock(&mutex_t); cout << "waiting 1s for thread...\n" <<endl; pthread_mutex_unlock(&mutex_t); int n =0; while(n<1E3){ pthread_testcancel(); sched_yield(); n++; pthread_mutex_lock(&mutex_t); cout << " Thread 1: "<< n<<endl; pthread_mutex_unlock(&mutex_t); } pthread_mutex_lock(&mutex_t); cout << "canceling thread...\n" <<endl; pthread_mutex_unlock(&mutex_t); if (pthread_cancel(thread_id) == 0) { //This doesn't wait for the thread to exit pthread_mutex_lock(&mutex_t); cout << "detaching thread...\n"<<endl; pthread_mutex_unlock(&mutex_t); pthread_detach(thread_id); while (pthread_kill(thread_id,0)==0) { sched_yield(); } pthread_mutex_lock(&mutex_t); cout << "thread is canceled"; pthread_mutex_unlock(&mutex_t); } pthread_mutex_lock(&mutex_t); cout << "exit"<<endl; pthread_mutex_unlock(&mutex_t); return 0; } When I replace the Cout with printf() i workes to the end "exit" , but with the cout (even locked) the executable hangs after outputting "detaching thread... It would be very cool to know from a Pro, what the problem here is?. Why does this not work even when cout is locked by a mutex!? Thanks a lot for your support!!

  Read the article

• Resumable upload from Java client to Grails web application?

  - by dersteps

  After almost 2 workdays of Googling and trying several different possibilities I found throughout the web, I'm asking this question here, hoping that I might finally get an answer. First of all, here's what I want to do: I'm developing a client and a server application with the purpose of exchanging a lot of large files between multiple clients on a single server. The client is developed in pure Java (JDK 1.6), while the web application is done in Grails (2.0.0). As the purpose of the client is to allow users to exchange a lot of large files (usually about 2GB each), I have to implement it in a way, so that the uploads are resumable, i.e. the users are able to stop and resume uploads at any time. Here's what I did so far: I actually managed to do what I wanted to do and stream large files to the server while still being able to pause and resume uploads using raw sockets. I would send a regular request to the server (using Apache's HttpClient library) to get the server to send me a port that was free for me to use, then open a ServerSocket on the server and connect to that particular socket from the client. Here's the problem with that: Actually, there are at least two problems with that: I open those ports myself, so I have to manage open and used ports myself. This is quite error-prone. I actually circumvent Grails' ability to manage a huge amount of (concurrent) connections. Finally, here's what I'm supposed to do now and the problem: As the problems I mentioned above are unacceptable, I am now supposed to use Java's URLConnection/HttpURLConnection classes, while still sticking to Grails. Connecting to the server and sending simple requests is no problem at all, everything worked fine. The problems started when I tried to use the streams (the connection's OutputStream in the client and the request's InputStream in the server). Opening the client's OutputStream and writing data to it is as easy as it gets. But reading from the request's InputStream seems impossible to me, as that stream is always empty, as it seems. Example Code Here's an example of the server side (Groovy controller): def test() { InputStream inStream = request.inputStream if(inStream != null) { int read = 0; byte[] buffer = new byte[4096]; long total = 0; println "Start reading" while((read = inStream.read(buffer)) != -1) { println "Read " + read + " bytes from input stream buffer" //<-- this is NEVER called } println "Reading finished" println "Read a total of " + total + " bytes" // <-- 'total' will always be 0 (zero) } else { println "Input Stream is null" // <-- This is NEVER called } } This is what I did on the client side (Java class): public void connect() { final URL url = new URL("myserveraddress"); final byte[] message = "someMessage".getBytes(); // Any byte[] - will be a file one day HttpURLConnection connection = url.openConnection(); connection.setRequestMethod("GET"); // other methods - same result // Write message DataOutputStream out = new DataOutputStream(connection.getOutputStream()); out.writeBytes(message); out.flush(); out.close(); // Actually connect connection.connect(); // is this placed correctly? // Get response BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream())); String line = null; while((line = in.readLine()) != null) { System.out.println(line); // Prints the whole server response as expected } in.close(); } As I mentioned, the problem is that request.inputStream always yields an empty InputStream, so I am never able to read anything from it (of course). But as that is exactly what I'm trying to do (so I can stream the file to be uploaded to the server, read from the InputStream and save it to a file), this is rather disappointing. I tried different HTTP methods, different data payloads, and also rearranged the code over and over again, but did not seem to be able to solve the problem. What I hope to find I hope to find a solution to my problem, of course. Anything is highly appreciated: hints, code snippets, library suggestions and so on. Maybe I'm even having it all wrong and need to go in a totally different direction. So, how can I implement resumable file uploads for rather large (binary) files from a Java client to a Grails web application without manually opening ports on the server side?

  Read the article

• PHP - DOM class - numbered entities and encodings problem

  - by user343607

  Hi guys, I'm having some difficult with PHP DOM class. I am making a sitemap script, and I need the output of $doc-saveXML() to be like <?xml version="1.0" encoding="UTF-8"?> <root> <url> <loc>http://www.somesite.com/servi&#xE7;os/redesign</loc> </url> </root> or <?xml version="1.0" encoding="UTF-8"?> <root> <url> <loc>http://www.somesite.com/servi&#231;os/redesign</loc> </url> </root> but I am getting: <?xml version="1.0" encoding="UTF-8"?> <root> <url> <loc>http://www.somesite.com/servi&amp;#xE7;os/redesign</loc> </url> </root> This is the closet I could get, using a replace named to numbered entities function. I was also able to reproduce <?xml version="1.0" ?> <root> <url> <loc>http://www.somesite.com/servi&amp;#xE7;os/redesign</loc> </url> </root> But without the encoding specified. The best solution (the way I think the code should be written) would be: <?php $myArray = array(); // do some stuff to populate the with URL strings $doc = new DOMDocument('1.0', 'UTF-8'); // here we modify some property. Maybe is the answer I am looking for... $urlset = doc->createElement("urlset"); $urlset = $doc->appendChild($urlset); foreach($myArray as $address) { $url = $doc->createElement("url"); $url = $urlset->appendChild($url); $loc = $doc->createElement("loc"); $loc = $url->appendChild($loc); $valueContent = $doc->createTextNode($value); $valueContent = $loc->appendChild($address); } echo $doc->saveXML(); ?> Notes: Server response header contains charset as UTF-8; PHP script is saved in UTF-8; URLs read are UTF-8 strings; Above script contains encoding declaration on DOMDocument constructor, and does not use any convert functions, like htmlentities, urlencode, utf8_encode... I've tried changing the DOMDocument properties DOMDocument::$resolveExternals and DOMDocument::$substituteEntities values. None combinations worked. And yes, I know I can made all process without specifying the character set on DOMDocument constructor, dump string content into a variable and make a very simple string substitution with string replace functions. This works. But I would like to know where I am slipping, how can this be made using native API's and settings, or even if this is possible. Thanks in advance.

  Read the article

< Previous Page | 550 551 552 553 554 555 556 557 558 559 560 561  | Next Page >