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  • Persistent (purely functional) Red-Black trees on disk performance

    - by Waneck
    I'm studying the best data structures to implement a simple open-source object temporal database, and currently I'm very fond of using Persistent Red-Black trees to do it. My main reasons for using persistent data structures is first of all to minimize the use of locks, so the database can be as parallel as possible. Also it will be easier to implement ACID transactions and even being able to abstract the database to work in parallel on a cluster of some kind. The great thing of this approach is that it makes possible implementing temporal databases almost for free. And this is something quite nice to have, specially for web and for data analysis (e.g. trends). All of this is very cool, but I'm a little suspicious about the overall performance of using a persistent data structure on disk. Even though there are some very fast disks available today, and all writes can be done asynchronously, so a response is always immediate, I don't want to build all application under a false premise, only to realize it isn't really a good way to do it. Here's my line of thought: - Since all writes are done asynchronously, and using a persistent data structure will enable not to invalidate the previous - and currently valid - structure, the write time isn't really a bottleneck. - There are some literature on structures like this that are exactly for disk usage. But it seems to me that these techniques will add more read overhead to achieve faster writes. But I think that exactly the opposite is preferable. Also many of these techniques really do end up with a multi-versioned trees, but they aren't strictly immutable, which is something very crucial to justify the persistent overhead. - I know there still will have to be some kind of locking when appending values to the database, and I also know there should be a good garbage collecting logic if not all versions are to be maintained (otherwise the file size will surely rise dramatically). Also a delta compression system could be thought about. - Of all search trees structures, I really think Red-Blacks are the most close to what I need, since they offer the least number of rotations. But there are some possible pitfalls along the way: - Asynchronous writes -could- affect applications that need the data in real time. But I don't think that is the case with web applications, most of the time. Also when real-time data is needed, another solutions could be devised, like a check-in/check-out system of specific data that will need to be worked on a more real-time manner. - Also they could lead to some commit conflicts, though I fail to think of a good example of when it could happen. Also commit conflicts can occur in normal RDBMS, if two threads are working with the same data, right? - The overhead of having an immutable interface like this will grow exponentially and everything is doomed to fail soon, so this all is a bad idea. Any thoughts? Thanks! edit: There seems to be a misunderstanding of what a persistent data structure is: http://en.wikipedia.org/wiki/Persistent_data_structure

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  • Memory corruption in System.Move due to changed 8087CW mode (png + stretchblt)

    - by André Mussche
    I have strange a memory corruption problem. After many hours debugging and trying I think I found something. For example: I do a simple string assignment: sTest := 'SET LOCK_TIMEOUT '; However, the result sometimes becomes: sTest = 'SET LOCK'#0'TIMEOUT ' So, the _ gets replaced by an 0 byte. I have seen this happening once (reproducing is tricky, dependent on timing) in the System.Move function, when it uses the FPU stack (fild, fistp) for fast memory copy (in case of 9 till 32 bytes to move): ... @@SmallMove: {9..32 Byte Move} fild qword ptr [eax+ecx] {Load Last 8} fild qword ptr [eax] {Load First 8} cmp ecx, 8 jle @@Small16 fild qword ptr [eax+8] {Load Second 8} cmp ecx, 16 jle @@Small24 fild qword ptr [eax+16] {Load Third 8} fistp qword ptr [edx+16] {Save Third 8} ... Using the FPU view and 2 memory debug views (Delphi - View - Debug - CPU - Memory) I saw it going wrong... once... could not reproduce however... This morning I read something about the 8087CW mode, and yes, if this is changed into $27F I get memory corruption! Normally it is $133F: The difference between $133F and $027F is that $027F sets up the FPU for doing less precise calculations (limiting to Double in stead of Extended) and different infiniti handling (which was used for older FPU’s, but is not used any more). Okay, now I found why but not when! I changed the working of my AsmProfiler with a simple check (so all functions are checked at enter and leave): if Get8087CW = $27F then //normally $1372? if MainThreadID = GetCurrentThreadId then //only check mainthread DebugBreak; I "profiled" some units and dll's and bingo (see stack): Windows.StretchBlt(3372289943,0,0,514,345,4211154027,0,0,514,345,13369376) pngimage.TPNGObject.DrawPartialTrans(4211154027,(0, 0, 514, 345, (0, 0), (514, 345))) pngimage.TPNGObject.Draw($7FF62450,(0, 0, 514, 345, (0, 0), (514, 345))) Graphics.TCanvas.StretchDraw((0, 0, 514, 345, (0, 0), (514, 345)),$7FECF3D0) ExtCtrls.TImage.Paint Controls.TGraphicControl.WMPaint((15, 4211154027, 0, 0)) So it is happening in StretchBlt... What to do now? Is it a fault of Windows, or a bug in PNG (included in D2007)? Or is the System.Move function not failsafe?

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  • Large number of UPDATE queries slowing down page

    - by Bryan Lewis
    I am reading and validating large fixed-width text files (range from 10-50K lines) that are submitted via our ASP.net website (coded in VB.Net). I do an initial scan of the file to check for basic issues (line length, etc). Then I import each row into a MS SQL table. Each DB rows basically consists of a record_ID (Primary, auto-incrementing) and about 50 varchar fields. After the insert is done, I run a validation function on the file that checks each field in each row based on a bunch of criteria (trimmed length, isnumeric, range checks, etc). If it finds an error in any field, it inserts a record into the Errors table, which has an error_ID, the record_ID and an error message. In addition, if the field fails in a particular way, I have to do a "reset" on that field. A reset might consist of blanking the entire field, or simply replacing the value with another value (e.g. replacing the string with a new one that has all illegals chars taken out). I have a 5,000 line test file. The upload, initial check, and import takes about 5-6 seconds. The detailed error check and insert into the Errors table takes about 5-8 seconds (this file has about 1200 errors in it). However, the "resets" part takes about 40-45 seconds for 750 fields that need to be reset. When I comment out the resets function (returning immediately without actually calling the UPDATE stored proc), the process is very fast. With the resets turned on, the pages take 50 seconds to return. My UPDATE stored proc is using some recommended code from http://sommarskog.se/dynamic_sql.html, whereby it uses CASE instead of dynamic SQL: UPDATE dbo.Records SET dbo.Records.file_ID = CASE @field_name WHEN 'file_ID' THEN @field_value ELSE file_ID END, . . (all 50 varchar field CASE statements here) . WHERE dbo.Records.record_ID = @record_ID Is there any way I can help my performance here. Can I somehow group all of these UPDATE calls into a single transaction? Should I be reworking the UPDATE query somehow? Or is it just sheer quantity of 750+ UPDATEs and things are just slow (it's a quad proc server with 8GB ram). Any suggestions appreciated.

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  • how to create a system-wide independent universal counter object primarily for Database keys?

    - by andora
    I would like to create/use a system-wide independent universal 'counter object' that can be called via COM in a thread-safe manner. The counter object will be passed an ID to identify which counter to return, handle the counting, 'persist' the count (occasionally), have reasonable performance (as fast as possible) perhaps capable of 1000 counts per second or better (1mS) and be accessible cross-process/out-of-process. The current count status must be persisted between object restarts/shutdowns. The counter object is liklely to be a 'singleton' type object implemented in some form of free-threaded dictionary, containing maybe 10 counters (perhaps 50 max). The count needs to be monotonic and consistent, (ie: guaranteed unique sequential values). Each counter should have a few methods, like reset, inc, dec, set, clear, remove. As a luxury, I would like to have a variable-increment (ie: 'step by' value). To support thread-safefty, perhaps some sorm of critical-section or mutex call. It just needs to return a long/4byte signed integer. I really want something that can be called from anywhere, including VBScript, so I figure COM is my preferred solution. The primary use of this is for database keys. I am unable to use autoinc or guid type keys and have ruled out database-generated counting systems at this point. I've spent days researching this and I have really struggled to find a solution. The best I can find is a free-threaded dictionary object that can be instantiated using COM+ from Motobit - it seems to offer all the 'basics' and I guess I could create some form of wrapper for this. So, here are my questions: Does such a 'general purpose counter-object already exist? Can you direct me to it? (MS did do an IIS/ASP object called 'MSWC.Counter' but this isn't 'cross-process'/ out-of-process component and isn't thread-safe. (but if it was, it would do!) What is the best way of creating such a Component? (I'd prefer VB6 right-now, [don't ask!] but can do in VB.NET2005 if I had to). I don't have the skills/knowledge/tools to use anything else. I am desparate for a workable solution. I need specific guidance! If anybody can code something up for me I am prepared to pay for it.

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  • Using empty row as default in a ComboBox with Style "DropDownList"?

    - by Pesche Helfer
    Hi board I am trying to write a method, that takes a ComboBox, a DataTable and a TextBox as arguments. The purpose of it is to filter the members displayed in the ComboBox according to the TextBox.Text. The DataTable contains the entire list of possible entries that will then be filtered. For filtering, I create a DataView of the DataTable, add a RowFilter and then bind this View to the ComboBox as DataSource. To prevent the user from typing into the ComboBox, I choose the DropDownStyle DropDownList. That’s working fine so far, except that the user should also be able to choose nothing / empty line. In fact, this should be the default member to be displayed (to prevent choosing a wrong member by accident, if the user clicks through the dialog too fast). I tried to solve this problem by adding a new Row to the view. While this works for some cases, the main issue here is that any DataTable can be passed to the method. If the DataTable contains columns that cannot be null and don’t contain a default value, I suppose I will raise an error by adding an empty row. A possibility would be to create a view that contains only the column that is defined as DisplayMember, and the one that is defined as ValueMember. Alas, this can’t be done with a view in C#. I would like to avoid creating a true copy of the DataTable at all cost, since who knows how big it will get with time. Do you have any suggestions how to get around this problem? Instead of a view, could I create an object containing two members and assign the DisplayMember and the ValueMember to these members? Would the members be passed as reference (what I hope) or would true copied be created (in which case it would not be a solution)? Thank you very much for your help! Best regards public static void ComboFilter(ComboBox cb, DataTable dtSource, TextBox filterTextBox) { cb.DropDownStyle = ComboBoxStyle.DropDownList; string displayMember = cb.DisplayMember; DataView filterView = new DataView(dtSource); filterView.AddNew(); filterView.RowFilter = displayMember + " LIKE '%" + filterTextBox.Text + "%'"; cb.DataSource = filterView; }

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  • Array not showing in Jlist but filled in console

    - by OVERTONE
    Hey there. been a busy debugger today. ill give ths short version. ive made an array list that takes names from a database. then i put the contents of the arraylist into an array of strings. now i want too display the arrays contents in a JList. the weird thing is it was working earlier. and ive two methods. ones just a little practice too make sure i was adding to the Jlist correctly. so heres the key codes. this is the layout of my code. variables constructor methods in my variables i have these 3 defined String[] contactListNames = new String[5]; ArrayList<String> rowNames = new ArrayList<String>(); JList contactList = new JList(contactListNames); simple enough. in my constructor i have them again. contactListNames = new String[5]; contactList = new JList(contactListNames); //i dont have the array list defined though. printSqlDetails(); // the prinSqldetails was too make sure that the connectionw as alright. and its working fine. fillContactList(); // this is the one thats causing me grief. its where all the work happens. // fillContactListTest(); // this was the tester that makes sure its adding to the list alright. heres the code for fillContactListTest() public void fillContactListTest() { for(int i = 0;i<3;i++) { try { String contact; System.out.println(" please fill the list at index "+ i); Scanner in = new Scanner(System.in); contact = in.next(); contactListNames[i] = contact; in.nextLine(); } catch(Exception e) { e.printStackTrace(); } } } heres the main one thats supposed too work. public void fillContactList() { int i =0; createConnection(); ArrayList<String> rowNames = new ArrayList<String>(); try { Statement stmt = conn.createStatement(); ResultSet namesList = stmt.executeQuery("SELECT name FROM Users"); try { while (namesList.next()) { rowNames.add(namesList.getString(1)); contactListNames =(String[])rowNames.toArray(new String[rowNames.size()]); // this used to print out contents of array list // System.out.println("" + rowNames); while(i<contactListNames.length) { System.out.println(" " + contactListNames[i]); i++; } } } catch(SQLException q) { q.printStackTrace(); } conn.commit(); stmt.close(); conn.close(); } catch(SQLException e) { e.printStackTrace(); } } i really need help here. im at my wits end. i just cant see why the first method would add to the JList no problem. but the second one wont. both the contactListNames array and array list can print fine and have the names in them. but i must be transfering them too the jlist wrong. please help p.s im aware this is long. but trust me its the short version.

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  • How to efficently build an interpreter (lexer+parser) in C?

    - by Rizo
    I'm trying to make a meta-language for writing markup code (such as xml and html) wich can be directly embedded into C/C++ code. Here is a simple sample written in this language, I call it WDI (Web Development Interface): /* * Simple wdi/html sample source code */ #include <mySite> string name = "myName"; string toCapital(string str); html { head { title { mySiteTitle; } link(rel="stylesheet", href="style.css"); } body(id="default") { // Page content wrapper div(id="wrapper", class="some_class") { h1 { "Hello, " + toCapital(name) + "!"; } // Lists post ul(id="post_list") { for(post in posts) { li { a(href=post.getID()) { post.tilte; } } } } } } } Basically it is a C source with a user-friendly interface for html. As you can see the traditional tag-based style is substituted by C-like, with blocks delimited by curly braces. I need to build an interpreter to translate this code to html and posteriorly insert it into C, so that it can be compiled. The C part stays intact. Inside the wdi source it is not necessary to use prints, every return statement will be used for output (in printf function). The program's output will be clean html code. So, for example a heading 1 tag would be transformed like this: h1 { "Hello, " + toCapital(name) + "!"; } // would become: printf("<h1>Hello, %s!</h1>", toCapital(name)); My main goal is to create an interpreter to translate wdi source to html like this: tag(attributes) {content} = <tag attributes>content</tag> Secondly, html code returned by the interpreter has to be inserted into C code with printfs. Variables and functions that occur inside wdi should also be sorted in order to use them as printf parameters (the case of toCapital(name) in sample source). I am searching for efficient (I want to create a fast parser) way to create a lexer and parser for wdi. Already tried flex and bison, but as I am not sure if they are the best tools. Are there any good alternatives? What is the best way to create such an interpreter? Can you advise some brief literature on this issue?

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  • Rails controller method going to plural form

    - by Jty.tan
    I'm new to rails! Ok, I am trying to set up a user signup form. It is mapped as a singular resource in the routes map.resource :user And trying to create the user through the console works fine. the controller code for user's signup is as follows: def signup @user = User.new#(params[:user]) end def create @user = User.new(params[:user]) #debugger if request.post? if @user.save session[:user] = User.authenticate(@user.login, @user.password) flash[:message] = "Signup successful" redirect_to registries_path else flash[:warning] = "Signup unsuccessful" #redirect_to 'user/signup' end end end The signup view is as follows (and this is where i think something is going wrong) <% form_tag user_path do %> <p>User creation.</p> <p><%= error_messages_for 'user' %></p> <p> <label>Username:</label> <%= text_field_tag 'login', nil, :size => 20, :maxlength => 20 %> </p> <p> <label>Password:</label> <%= password_field_tag 'password', nil, :size => 20, :maxlength => 20 %> </p> <p> <label>Password confirmation:</label> <%= password_field_tag 'password_confirmation', nil, :size => 20, :maxlength => 20 %> </p> <p> <label>Email:</label> <%= text_field_tag 'email' %> </p> <p><%= submit_tag 'Signup' %></p> <% end %> Now, that page renders just fine. I've called the form on the "user_path" which is singular (i think?). But when I hit the submit button, it gives me an error saying that uninitialized constant UsersController the occurence of the error makes sense, since User is meant to be singular, so if it is trying to call the Users controller, it should be chucking an error. When I checked the server log, it shows this message: Processing ApplicationController#create (for 127.0.0.1 at 2010-05-08 16:26:14) [POST] Parameters: {"commit"=>"Signup", "password_confirmation"=>"[FILTERED]", "action"=>"create", "authenticity_token"=>"yOcHY+rMjaqmu9HS8EwnDqJKbc0Zxictc0y4dtD26ac=", "controller"=>"users", "login"=>"bob", "password"=>"[FILTERED]", "email"=>"[email protected]"} NameError (uninitialized constant UsersController): In the params, I can see that it is calling the "users" controller. But I'm not sure how to fix that, or what is causing it to call the "users" controller as opposed to the "user" controller. Any ideas? Thanks in advance!

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  • approximating log10[x^k0 + k1]

    - by Yale Zhang
    Greetings. I'm trying to approximate the function Log10[x^k0 + k1], where .21 < k0 < 21, 0 < k1 < ~2000, and x is integer < 2^14. k0 & k1 are constant. For practical purposes, you can assume k0 = 2.12, k1 = 2660. The desired accuracy is 5*10^-4 relative error. This function is virtually identical to Log[x], except near 0, where it differs a lot. I already have came up with a SIMD implementation that is ~1.15x faster than a simple lookup table, but would like to improve it if possible, which I think is very hard due to lack of efficient instructions. My SIMD implementation uses 16bit fixed point arithmetic to evaluate a 3rd degree polynomial (I use least squares fit). The polynomial uses different coefficients for different input ranges. There are 8 ranges, and range i spans (64)2^i to (64)2^(i + 1). The rational behind this is the derivatives of Log[x] drop rapidly with x, meaning a polynomial will fit it more accurately since polynomials are an exact fit for functions that have a derivative of 0 beyond a certain order. SIMD table lookups are done very efficiently with a single _mm_shuffle_epi8(). I use SSE's float to int conversion to get the exponent and significand used for the fixed point approximation. I also software pipelined the loop to get ~1.25x speedup, so further code optimizations are probably unlikely. What I'm asking is if there's a more efficient approximation at a higher level? For example: Can this function be decomposed into functions with a limited domain like log2((2^x) * significand) = x + log2(significand) hence eliminating the need to deal with different ranges (table lookups). The main problem I think is adding the k1 term kills all those nice log properties that we know and love, making it not possible. Or is it? Iterative method? don't think so because the Newton method for log[x] is already a complicated expression Exploiting locality of neighboring pixels? - if the range of the 8 inputs fall in the same approximation range, then I can look up a single coefficient, instead of looking up separate coefficients for each element. Thus, I can use this as a fast common case, and use a slower, general code path when it isn't. But for my data, the range needs to be ~2000 before this property hold 70% of the time, which doesn't seem to make this method competitive. Please, give me some opinion, especially if you're an applied mathematician, even if you say it can't be done. Thanks.

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  • Neo4j 1.9.4 (REST Server,CYPHER) performance issue

    - by user2968943
    I have Neo4j 1.9.4 installed on 24 core 24Gb ram (centos) machine and for most queries CPU usage spikes goes to 200% with only few concurrent requests. Domain: some sort of social application where few types of nodes(profiles) with 3-30 text/array properties and 36 relationship types with at least 3 properties. Most of nodes currently has ~300-500 relationships. Current data set footprint(from console): LogicalLogSize=4294907 (32MB) ArrayStoreSize=1675520 (12MB) NodeStoreSize=1342170 (10MB) PropertyStoreSize=1739548 (13MB) RelationshipStoreSize=6395202 (48MB) StringStoreSize=1478400 (11MB) which is IMHO really small. most queries looks like this one(with more or less WITH .. MATCH .. statements and few queries with variable length relations but the often fast): START targetUser=node({id}), currentUser=node({current}) MATCH targetUser-[contact:InContactsRelation]->n, n-[:InLocationRelation]->l, n-[:InCategoryRelation]->c WITH currentUser, targetUser,n, l,c, contact.fav is not null as inFavorites MATCH n<-[followers?:InContactsRelation]-() WITH currentUser, targetUser,n, l,c,inFavorites, COUNT(followers) as numFollowers RETURN id(n) as id, n.name? as name, n.title? as title, n._class as _class, n.avatar? as avatar, n.avatar_type? as avatar_type, l.name as location__name, c.name as category__name, true as isInContacts, inFavorites as isInFavorites, numFollowers it runs in ~1s-3s(for first run) and ~1s-70ms (for consecutive and it depends on query) and there is about 5-10 queries runs for each impression. Another interesting behavior is when i try run query from console(neo4j) on my local machine many consecutive times(just press ctrl+enter for few seconds) it has almost constant execution time but when i do it on server it goes slower exponentially and i guess it somehow related with my problem. Problem: So my problem is that neo4j is very CPU greedy(for 24 core machine its may be not an issue but its obviously overkill for small project). First time i used AWS EC2 m1.large instance but over all performance was bad, during testing, CPU always was over 100%. Some relevant parts of configuration: neostore.nodestore.db.mapped_memory=1280M wrapper.java.maxmemory=8192 note: I already tried configuration where all memory related parameters where HIGH and it didn't worked(no change at all). Question: Where to digg? configuration? scheme? queries? what i'm doing wrong? if need more info(logs, configs) just ask ;)

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  • jquery, manipulate content inserted by ajax, without using the callback

    - by Cody
    I am using ajax to insert a series of informational blocks via a loop. The blocks each have a title, and long description in them that is hidden by default. They function like an accordion, only showing one description at a time amongst all of the blocks. The problem is opening the description on the first block. I would REALLY like to do it with javascript right after the loop that is creating them is done. Is it possible to manipulate elements created ofter an ajax call without using the callback? <!-- example code--> <style> .placeholder, .long_description{ display:none;} </style> </head><body> <script> /* yes, this script is in the body, dont know if it matters */ $(document).ready(function() { $(".placeholder").each(function(){ // Use the divs to get the blocks var blockname = $(this).html(); // the contents if the div is the ID for the ajax POST $.post("/service_app/dyn_block",'form='+blockname, function(data){ var divname = '#div_' + blockname; $(divname).after(data); $(this).setupAccrdFnctly(); //not the actual code }); }); /* THIS LINE IS THE PROBLEM LINE, is it possible to reference the code ajax inserted */ /* Display the long description in the first dyn_block */ $(".dyn_block").first().find(".long_description").addClass('active').slideDown('fast'); }); </script> <!-- These lines are generated by PHP --> <!-- It is POSSIBLE to display the dyn_blocks --> <!-- here but I would really rather not --> <div id="div_servicetype" class="placeholder">servicetype</div> <div id="div_custtype" class="placeholder">custtype</div> <div id="div_custinfo" class="placeholder">custinfo</div> <div id="div_businfo" class="placeholder">businfo</div> </body>

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  • Using Singleton synchronized array with NSThread

    - by hmthur
    I have a books app with a UISearchBar, where the user types any book name and gets search results (from ext API call) below as he types. I am using a singleton variable in my app called retrievedArray which stores all the books. @interface Shared : NSObject { NSMutableArray *books; } @property (nonatomic, retain) NSMutableArray *books; + (id)sharedManager; @end This is accessed in multiple .m files using NSMutableArray *retrievedArray; ...in the header file retrievedArray = [[Shared sharedManager] books]; My question is how do I ensure that the values inside retrievedArray remain synchronized across all the classes. Actually the values inside retrievedArray gets added through an NSXMLParser (i.e. through external web service API). There is a separate XMLParser.m file, where I do all the parsing and fill the array. The parsing is done on a separate thread. - (void) run: (id) param { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; NSXMLParser *parser = [[NSXMLParser alloc] initWithContentsOfURL: [self URL]]; [parser setDelegate: self]; [parser parse]; [parser release]; NSString *tmpURLStr = [[self URL]absoluteString]; NSRange range_srch_book = [tmpURLStr rangeOfString:@"v1/books"]; if (range_srch_book.location != NSNotFound) [delegate performSelectorOnMainThread:@selector(parseDidComplete_srch_book) withObject:nil waitUntilDone:YES]; [pool release]; } - (void) parseXMLFile: (NSURL *) url { NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; [self setURL: url]; NSThread* myThread = [[NSThread alloc] initWithTarget:self selector:@selector(run:) object: nil]; [retrievedArray removeAllObjects]; [myThread start]; [pool release]; } There seems to be some synchronization issues if the user types very quickly (It seems to be working fine if the user types slowly)....So there are 2 views in which the content of an object in this shared array item is displayed; List and Detail. If user types fast and clicks on A in List view, he is shown B in detail view...That is the main issue. I have tried literally all the solutions I could think of, but am still unable to fix the issue. Please suggest some suitable fixes.

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  • Lockless queue implementation ends up having a loop under stress

    - by Fozi
    I have lockless queues written in C in form of a linked list that contains requests from several threads posted to and handled in a single thread. After a few hours of stress I end up having the last request's next pointer pointing to itself, which creates an endless loop and locks up the handling thread. The application runs (and fails) on both Linux and Windows. I'm debugging on Windows, where my COMPARE_EXCHANGE_PTR maps to InterlockedCompareExchangePointer. This is the code that pushes a request to the head of the list, and is called from several threads: void push_request(struct request * volatile * root, struct request * request) { assert(request); do { request->next = *root; } while(COMPARE_EXCHANGE_PTR(root, request, request->next) != request->next); } This is the code that gets a request from the end of the list, and is only called by a single thread that is handling them: struct request * pop_request(struct request * volatile * root) { struct request * volatile * p; struct request * request; do { p = root; while(*p && (*p)->next) p = &(*p)->next; // <- loops here request = *p; } while(COMPARE_EXCHANGE_PTR(p, NULL, request) != request); assert(request->next == NULL); return request; } Note that I'm not using a tail pointer because I wanted to avoid the complication of having to deal with the tail pointer in push_request. However I suspect that the problem might be in the way I find the end of the list. There are several places that push a request into the queue, but they all look generaly like this: // device->requests is defined as struct request * volatile requests; struct request * request = malloc(sizeof(struct request)); if(request) { // fill out request fields push_request(&device->requests, request); sem_post(device->request_sem); } The code that handles the request is doing more than that, but in essence does this in a loop: if(sem_wait_timeout(device->request_sem, timeout) == sem_success) { struct request * request = pop_request(&device->requests); // handle request free(request); } I also just added a function that is checking the list for duplicates before and after each operation, but I'm afraid that this check will change the timing so that I will never encounter the point where it fails. (I'm waiting for it to break as I'm writing this.) When I break the hanging program the handler thread loops in pop_request at the marked position. I have a valid list of one or more requests and the last one's next pointer points to itself. The request queues are usually short, I've never seen more then 10, and only 1 and 3 the two times I could take a look at this failure in the debugger. I thought this through as much as I could and I came to the conclusion that I should never be able to end up with a loop in my list unless I push the same request twice. I'm quite sure that this never happens. I'm also fairly sure (although not completely) that it's not the ABA problem. I know that I might pop more than one request at the same time, but I believe this is irrelevant here, and I've never seen it happening. (I'll fix this as well) I thought long and hard about how I can break my function, but I don't see a way to end up with a loop. So the question is: Can someone see a way how this can break? Can someone prove that this can not? Eventually I will solve this (maybe by using a tail pointer or some other solution - locking would be a problem because the threads that post should not be locked, I do have a RW lock at hand though) but I would like to make sure that changing the list actually solves my problem (as opposed to makes it just less likely because of different timing).

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  • Migrating from hand-written persistence layer to ORM

    - by Sergey Mikhanov
    Hi community, We are currently evaluating options for migrating from hand-written persistence layer to ORM. We have a bunch of legacy persistent objects (~200), that implement simple interface like this: interface JDBC { public long getId(); public void setId(long id); public void retrieve(); public void setDataSource(DataSource ds); } When retrieve() is called, object populates itself by issuing handwritten SQL queries to the connection provided using the ID it received in the setter (this usually is the only parameter to the query). It manages its statements, result sets, etc itself. Some of the objects have special flavors of retrive() method, like retrieveByName(), in this case a different SQL is issued. Queries could be quite complex, we often join several tables to populate the sets representing relations to other objects, sometimes join queries are issued on-demand in the specific getter (lazy loading). So basically, we have implemented most of the ORM's functionality manually. The reason for that was performance. We have very strong requirements for speed, and back in 2005 (when this code was written) performance tests has shown that none of mainstream ORMs were that fast as hand-written SQL. The problems we are facing now that make us think of ORM are: Most of the paths in this code are well-tested and are stable. However, some rarely-used code is prone to result set and connection leaks that are very hard to detect We are currently squeezing some additional performance by adding caching to our persistence layer and it's a huge pain to maintain the cached objects manually in this setup Support of this code when DB schema changes is a big problem. I am looking for an advice on what could be the best alternative for us. As far as I know, ORMs has advanced in last 5 years, so it might be that now there's one that offers an acceptable performance. As I see this issue, we need to address those points: Find some way to reuse at least some of the written SQL to express mappings Have the possibility to issue native SQL queries without the necessity to manually decompose their results (i.e. avoid manual rs.getInt(42) as they are very sensitive to schema changes) Add a non-intrusive caching layer Keep the performance figures. Is there any ORM framework you could recommend with regards to that?

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  • Working with friends. Poor career choice?

    - by a_person
    Hi all, Hope you can help me solve somewhat of a moral dilemma. Some time ago, after just a few years of living in U.S. and having to take any job I could get my hands on a friend of mine submitted recommended me for an open position at the company that he was working for. I could have not been happier. I do not have a degree of any sort, however, by being passionate about CS and with constant drive for self education I've became a somewhat of a strong generalist. Every place I worked for recognized me for that quality and used me on various projects where set of technology in hand had no overlap with set of knowledge of the team members. Rapidly I've advanced to Sr. Programmer position and the trend of me following a friend from one place to another have started and continued on for a few years. My friend's goal always been to become an IT Director, mine is to become the best programmer I can be. To my knowledge I've accommodated his goals as much as I could by taking a back seat, and letting him take the lead. Fast forward to today. He's a manager, and I am on his team. I am unhappy and I in considerable amount of suffering. I am not being utilized to my potential, it's almost exact opposite, I am being micromanaged to an unhealthy extent, my decisions, and suggestions are constantly met with negative connotation. Last week I had to hear about how my friend is a better programmer than I am. My ego was ecstatic about this one /s. In addition to that working in the field of BI have exhausted itself for most parts. The only pleasure of my work is being derived from making everything as dynamic and parameter driven as possible. This is the only area where a friend of mine does not feel competent enough to actually micromanage. Because of my situation I feel a fair amount of guilt and ever growing resentment. I need your advice, maybe you've dealt with this expression of ego before, needs of self vs the needs of your friend. Is working with a friend a poor choice? Thank you for reading in.

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  • Multi-threaded Pooled Allocators

    - by Darren Engwirda
    I'm having some issues using pooled memory allocators for std::list objects in a multi-threaded application. The part of the code I'm concerned with runs each thread function in isolation (i.e. there is no communication or synchronization between threads) and therefore I'd like to setup separate memory pools for each thread, where each pool is not thread-safe (and hence fast). I've tried using a shared thread-safe singleton memory pool and found the performance to be poor, as expected. This is a heavily simplified version of the type of thing I'm trying to do. A lot has been included in a pseudo-code kind of way, sorry if it's confusing. /* The thread functor - one instance of MAKE_QUADTREE created for each thread */ class make_quadtree { private: /* A non-thread-safe memory pool for int linked list items, let's say that it's * something along the lines of BOOST::OBJECT_POOL */ pooled_allocator<int> item_pool; /* The problem! - a local class that would be constructed within each std::list as the * allocator but really just delegates to ITEM_POOL */ class local_alloc { public : //!! I understand that I can't access ITEM_POOL from within a nested class like //!! this, that's really my question - can I get something along these lines to //!! work?? pointer allocate (size_t n) { return ( item_pool.allocate(n) ); } }; public : make_quadtree (): item_pool() // only construct 1 instance of ITEM_POOL per // MAKE_QUADTREE object { /* The kind of data structures - vectors of linked lists * The idea is that all of the linked lists should share a local pooled allocator */ std::vector<std::list<int, local_alloc>> lists; /* The actual operations - too complicated to show, but in general: * * - The vector LISTS is grown as a quadtree is built, it's size is the number of * quadtree "boxes" * * - Each element of LISTS (each linked list) represents the ID's of items * contained within each quadtree box (say they're xy points), as the quadtree * is grown a lot of ID pop/push-ing between lists occurs, hence the memory pool * is important for performance */ } }; So really my problem is that I'd like to have one memory pool instance per thread functor instance, but within each thread functor share the pool between multiple std::list objects.

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  • Cloning a selector + all its children in jQuery?

    - by HipHop-opatamus
    I'm having trouble getting the following JQuery script to function properly - its functionality is as follows: 1) Hide the content below each headline 2) Upon clicking a headline, substitute the "#first-post" with the headline + the hidden content below the headline. I can only seem to get the script to clone the headline itself to #first-post, not the headline + the content beneath it. Any idea why? <HTML> <HEAD> <script src="http://code.jquery.com/jquery-latest.js"></script> </HEAD> <script> $(document).ready( function(){ $('.title').siblings().hide(); $('.title').click( function() { $('#first-post').replaceWith($(this).closest(".comment").clone().attr('id','first-post')); $('html, body').animate({scrollTop:0}, 'fast'); return false; }); }); </script> <BODY> <div id="first-post"> <div class="content"><p>This is a test discussion topic</p> </div> </div> <div class="comment"> <h2 class="title"><a href="#1">1st Post</a></h2> <div class="content"> <p>this is 1st reply to the original post</p> </div> <div class="test">1st post second line</div> </div> <div class="comment"> <h2 class="title"><a href="#2">2nd Post</a></h2> <div class="content"> <p>this is 2nd reply to the original post</p> </div> <div class="test">2nd post second line</div> </div> </div> <div class="comment"> <h2 class="title"><a href="#3">3rd Post</a></h2> <div class="content"> <p>this is 3rd reply to the original post</p> </div> <div class="test">3rd post second line</div> </div> </div> </BODY> </HTML>

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  • Node.js, Cygwin and Socket.io walk into a bar... Node.js throws ENOBUFS and everyone dies...

    - by A Wizard Did It
    I'm hoping someone here can help me out, I'm not having much luck figuring this out myself. I'm running node.js version 0.3.1 on Cygwin. I'm using Connect and Socket.io. I seem to be having some random problems with DNS or something, I haven't quite figured it out. The end result is that I the server is running fine, but when a browser attempts to connect to it the initial HTTP Request works, Socket.io connects, and then the server dies (output below). I don't think it has anything to do with the HTTP request because the server gets a lot data posted to it, and it was receiving requests and responding up until my connection that killed it. I've googled around and the closest thing I've found is DNS being set improperly. It's a network program meant to run only on an internal network, so I've set the nameserver x.x.x.x in my /etc/resolv.conf to the internal DNS. I've also added nameserver 8.8.8.8 in addition. I'm not sure what else to check, but would be grateful of any help. In node.exe.stackdump Exception: STATUS_ACCESS_VIOLATION at eip=610C51B9 eax=00000000 ebx=00000001 ecx=00000000 edx=00000308 esi=00000000 edi=010FCCB0 ebp=010FCAEC esp=010FCAC4 program=\\?\E:\cygwin\usr\local\bin\node.exe, pid 3296, thread unknown (0xBEC) cs=0023 ds=002B es=002B fs=0053 gs=002B ss=002B Stack trace: Frame Function Args 010FCAEC 610C51B9 (00000000, 00000000, 00000000, 00000000) 010FCBFC 610C5B55 (00000000, 00000000, 00000000, 00000000) 010FCCBC 610C693A (FFFFFFFF, FFFFFFFF, 750334F3, FFFFFFFE) 010FCD0C 61027CB2 (00000002, F4B994D5, 010FCE64, 00000002) 010FCD98 76306B59 (00000002, 010FCDD4, 763069A4, 00000002) End of stack trace Node Output: node.js:50 throw e; // process.nextTick error, or 'error' event on first tick ^ Error: ENOBUFS, No buffer space available at doConnect (net.js:642:19) at net.js:803:9 at dns.js:166:30 at IOWatcher.callback (dns.js:48:15) EDIT I'm hitting an LDAP server using http.createClient immediately after a client connects to get information, and that seems to be where the problem is that is causing ENOBUFS. I've edited the source to include && errno != ENOBUFS which now prevents the server from dying, however now the LDAP request isn't working. I'm not sure what the problem is that would cause that though. As I mentioned this is an internal only application, so I set the DNS servers in /etc/resolv.conf to the DNS servers that are being applied to the host machine. Not sure if this is part of the issue? EDIT 2 Here's some output from gdb --args ./node_g --debug ../myscript.js. I'm not sure if this is related to ENOBUFS, however, as it seems to be disconnecting immediately after connection with Socket.io [New thread 672.0x100] Error: dll starting at 0x76e30000 not found. Error: dll starting at 0x76250000 not found. Error: dll starting at 0x76e30000 not found. Error: dll starting at 0x76f50000 not found. [New thread 672.0xc90] [New thread 672.0x448] debugger listening on port 5858 [New thread 672.0xbf4] 14 Jan 18:48:57 - socket.io ready - accepting connections [New thread 672.0xed4] [New thread 672.0xd68] [New thread 672.0x1244] [New thread 672.0xf14] 14 Jan 18:49:02 - Initializing client with transport "websocket" assertion "b[1] == 0" failed: file "../src/node.cc", line 933, function: ssize_t node::DecodeWrite(char*, size_t, v8::Handle<v8::Value>, node::encoding) Program received signal SIGABRT, Aborted. 0x7724f861 in ntdll!RtlUpdateClonedSRWLock () from /cygdrive/c/Windows/system32/ntdll.dll (gdb) backtrace #0 0x7724f861 in ntdll!RtlUpdateClonedSRWLock () from /cygdrive/c/Windows/system32/ntdll.dll #1 0x7724f861 in ntdll!RtlUpdateClonedSRWLock () from /cygdrive/c/Windows/system32/ntdll.dll #2 0x75030816 in WaitForSingleObjectEx () from /cygdrive/c/Windows/syswow64/KernelBase.dll #3 0x0000035c in ?? () #4 0x00000000 in ?? () (gdb)

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  • Java Socket Connection is flooding network OR resulting in high ping

    - by user1461100
    i have a little problem with my java socket code. I'm writing an android client application which is sending data to a java multithreaded socket server on my pc through direct(!) wireless connection. It works fine but i want to improve it for mobile applications as it is very power consuming by now. When i remove two special lines in my code, the cpu usage of my mobile device (htc one x) is totally okay but then my connection seems to have high ping rates or something like that... Here is a server code snippet where i receive the clients data: while(true) { try { .... Object obj = in.readObject(); if(obj != null) { Class clazz = obj.getClass(); String className = clazz.getName(); if(className.equals("java.lang.String")) { String cmd = (String)obj; if(cmd.equals("dc")) { System.out.println("Client "+id+" disconnected!"); Server.connectedClients[id-1] = false; break; } if(cmd.substring(0,1).equals("!")) { robot.keyRelease(PlayerEnum.getKey(cmd,id)); } else { robot.keyPress(PlayerEnum.getKey(cmd,id)); } } } } catch .... Heres the client part, where i send my data in a while loop: private void networking() { try { if(client != null) { .... out.writeObject(sendQueue.poll()); .... } } catch .... when i write it this why, i send data everytime the while loop gets executed.. when sendQueue is empty, a null "Object" will be send. this results in "high" network traffic and in "high" cpu usage. BUT: all send comments are received nearly immediately. when i change the code to following: while(true) ... if(sendQueue.peek() != null) { out.writeObject(sendQueue.poll()); } ... the cpu usage is totally okay but i'm getting some laggs.. the commands do not arrive fast enough.. as i said, it works fine (besides cpu usage) if i'm sending data(with that null objects) every while execution. but i'm sure that this is very rough coding style because i'm kind of flooding the network. any hints? what am i doing wrong?? Thanks for your Help! Sincerly yours, maaft

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  • Implementing coroutines in Java

    - by JUST MY correct OPINION
    This question is related to my question on existing coroutine implementations in Java. If, as I suspect, it turns out that there is no full implementation of coroutines currently available in Java, what would be required to implement them? As I said in that question, I know about the following: You can implement "coroutines" as threads/thread pools behind the scenes. You can do tricksy things with JVM bytecode behind the scenes to make coroutines possible. The so-called "Da Vinci Machine" JVM implementation has primitives that make coroutines doable without bytecode manipulation. There are various JNI-based approaches to coroutines also possible. I'll address each one's deficiencies in turn. Thread-based coroutines This "solution" is pathological. The whole point of coroutines is to avoid the overhead of threading, locking, kernel scheduling, etc. Coroutines are supposed to be light and fast and to execute only in user space. Implementing them in terms of full-tilt threads with tight restrictions gets rid of all the advantages. JVM bytecode manipulation This solution is more practical, albeit a bit difficult to pull off. This is roughly the same as jumping down into assembly language for coroutine libraries in C (which is how many of them work) with the advantage that you have only one architecture to worry about and get right. It also ties you down to only running your code on fully-compliant JVM stacks (which means, for example, no Android) unless you can find a way to do the same thing on the non-compliant stack. If you do find a way to do this, however, you have now doubled your system complexity and testing needs. The Da Vinci Machine The Da Vinci Machine is cool for experimentation, but since it is not a standard JVM its features aren't going to be available everywhere. Indeed I suspect most production environments would specifically forbid the use of the Da Vinci Machine. Thus I could use this to make cool experiments but not for any code I expect to release to the real world. This also has the added problem similar to the JVM bytecode manipulation solution above: won't work on alternative stacks (like Android's). JNI implementation This solution renders the point of doing this in Java at all moot. Each combination of CPU and operating system requires independent testing and each is a point of potentially frustrating subtle failure. Alternatively, of course, I could tie myself down to one platform entirely but this, too, makes the point of doing things in Java entirely moot. So... Is there any way to implement coroutines in Java without using one of these four techniques? Or will I be forced to use the one of those four that smells the least (JVM manipulation) instead?

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  • How do you remind your Scrum Product Owner about his promises/actions?

    - by Felix Ogg
    ** EDIT: Rephrased the question to re-focus ** Our Scrum team meets as seldomly as possible, but we meet with the product owner every chance we get. We track everyone's agreed action points (particularly theirs). We are 100% agile, but our product owner lives in traditional world, we remain off-site. We facilitate him in crossing over to our fast-paced world. There's not much wrong. The team and the PO are in good spirits. PO is present at every meeting and positively energized. Just imagine this person as a 70 year old, slow grandpa, who is forgetful, yet kind. In reality he isn't, but he is used to a working environment (public servants) that is much slooooower. Manyana-manyana etc. It is frustrating for my team to cooperate: PO lives in a non-prioritized environment, and everyone in it has learned the productivity-technique of NGTD (Not Getting Things Done). He WANTS to, it's just that he forgets or 'sinks' somewhere along the away. We have experimented with a text file, maintained by the Scrum master (low-tech), which he broadcasts by e-mail every day JIRA, our issue tracker. Turns out this is nice for programmers, but too steep for 'regular people' I Googled for Issue tracking webtools but came up empty handed: All tools are aimed at IT issue tracking, instead of meeting action point tracking/planning for mere mortals. I did find TODO-lists like RememberTheMilk, but they don't track comments, and - to be honest - I doubt we could get our product owner to use it (too complicated). We have three requirements: Register action points, assign to a team member and a deadline Offer anyone to 'comment' on progress of any action point Do not build our own tool from scratch We do not need: - impressive authorization models, - multi-project, - workflow, - crosslinking. Is there any trick/tool you use to assist your product owner 'fly' like the rest of the rest of the team? Communication before tools I agree with the general consensus that one should not try to apply technology to a communication problem, however in this case I am merely looking for a tool to save me time in setting up prioritized lists. I found www.thymer.com today, may be what I am looking for. The guys are cool. It is getting rather feature-bloated though.

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  • jQuery to hide and show divs with an indicator

    - by songdogtech
    Using the jQuery below to toggle the hiding and showing of divs of text: how would I add some sort of indicator - like an up and down arrow as a graphic - to the titles when the divs are either open and closed? What's the best way to do that? Two images? A CSS sprite? And most importantly: how would that be integrated into the JS? I've looked at other jQuery that assigns a random number to each div and then determines which are open and which are closed and toggles one of two images. But I'm using php in a WordPress loop to show a posts, and that gives problems with incrementing in the loop, so there must be an easier way that doesn't require changes in the name of the title div. Thanks.... This JS fires the showing and hiding. Each div can be expanded and collapsed independently. $(document).ready(function() { $('div.demo-show:eq(0)> div').hide(); $('div.demo-show:eq(0)> h3').click(function() { $(this).next().slideToggle('fast'); }); }); This is the HTML it works with: <div class="collapser"> <p class="title">Header-1 </p> <div class="contents">Lorem ipsum</div> <p class="title">Header-2</p> <div class="contents">Lorem ipsum </div> <p class="title">Header-3</p> <div class="contents">Lorem ipsum</div> </div> The CSS is arbitrary: .collapser { margin: 0; padding: 0; width: 500px; } .title { margin: 1px; color: #fff; padding: 3px 10px; cursor: pointer; position: relative; background-color:#c30; } .contents { padding: 5px 10px; background-color:#fafafa; }

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  • Change the Session Variable Output

    - by user567230
    Hello I am using Dreamweaver CS5 with Coldfusion 9 to build a dynamic website. I have a MS Access Database that stores login information which includes ID, FullName, FirstName, LastName, Username, Pawword, AcessLevels. My question is this: I currently have session variable to track the Username when it is entered into the login page. However I would like to use that Username to pull the User's FullName to display throughout the web pages and use for querying data. How do I change the session variable to read that when they are not entering their FullName on the login page but only Username and password. I have listed my login information code below if there is any additional information needed please let me know. This is the path for which the FullName values reside DataSource "Access" Table "Logininfo" Field "FullName" I want the FullName to be unique based on the Username submitted from the Login page. I apologize in advance for any rookie mistake I may have made I am new to this but learning fast! Ha. <cfif IsDefined("FORM.username")> <cfset MM_redirectLoginSuccess="members_page.cfm"> <cfset MM_redirectLoginFailed="sorry.cfm"> <cfquery name="MM_rsUser" datasource="Access"> SELECT FullName, Username,Password,AccessLevels FROM Logininfo WHERE Username=<cfqueryparam value="#FORM.username#" cfsqltype="cf_sql_clob" maxlength="50"> AND Password=<cfqueryparam value="#FORM.password#" cfsqltype="cf_sql_clob" maxlength="50"> </cfquery> <cfif MM_rsUser.RecordCount NEQ 0> <cftry> <cflock scope="Session" timeout="30" type="Exclusive"> <cfset Session.MM_Username=FORM.username> <cfset Session.MM_UserAuthorization=MM_rsUser.AccessLevels[1]> </cflock> <cfif IsDefined("URL.accessdenied") AND false> <cfset MM_redirectLoginSuccess=URL.accessdenied> </cfif> <cflocation url="#MM_redirectLoginSuccess#" addtoken="no"> <cfcatch type="Lock"> <!--- code for handling timeout of cflock ---> </cfcatch> </cftry> </cfif> <cflocation url="#MM_redirectLoginFailed#" addtoken="no"> <cfelse> <cfset MM_LoginAction=CGI.SCRIPT_NAME> <cfif CGI.QUERY_STRING NEQ ""> <cfset MM_LoginAction=MM_LoginAction & "?" & XMLFormat(CGI.QUERY_STRING)> </cfif> </cfif>

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  • What makes great software?

    - by VirtuosiMedia
    From the perspective of an end user, what makes a software great rather than just good or functional? What are some fundamental principles that can shift the way a software is used and perceived? What are some of the little finishing touches that help put an application over the top? I'm in the later stages of developing a web app and I'm looking for ideas or concepts that I may have missed. If you have specific examples of software or apps that you absolutely love, please share the reasons or features that make it special. Keep in mind that I'm looking for examples that directly affect the end user, but not necessarily just UI suggestions. Here are some of the principles and little touches I'm trying to use: Keep the UI as simple as possible. Remove absolutely everything that isn't necessary. Use progressive disclosure when more information can be needed sometimes but isn't needed all the time. Provide inline help and useful error messages. Verbs on buttons wherever possible. Make anything that's clickable obvious. Fast, responsive UI. Accessibility (this is a work in progress). Reusable UI patterns. Once a user learns a skill, they will be able to use it in multiple places. Intelligent default settings. Auto-focusing forms when filling out the form is the primary action to be taken on the page. Clear metaphors (like tabs) and headings indicating location within the app. Automating repetitive tasks (with the ability to disable the automation). Use standardized or accepted metaphors for icons (like an "x" for delete). Larger text sizes for improved readability. High contrast so that each section is distinct. Making sure that it's obvious on every page what the user is supposed to do by establishing a clear information hierarchy and drawing the eye to the call to action. Most deletions can be undone. Discoverability - Make it easy to learn how to do new tasks. Group similar elements together.

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  • jQuery Validation in ASP.NET

    - by Abu Hamzah
    i have a strange situation may its a easy fix or something i may be missing but here is the question. i have a asp.net form with master page and my validation works great without any problem but the problems starts when i try to hook my click event to the server side, here is what i meant: i have a form with few fields on it and if the form is empty than it should STOP submitting, otherwise allow me to execute the server side script but its not happening, even my form is in invalid state (i do get error message saying i have to enter the required fileds) but still executing my server side script. i would like to execute my server side script only if the form is in valid state. here is my code: my master page <%@ Master Language="C#" AutoEventWireup="true" CodeFile="MasterPage.master.cs" Inherits="MasterPage" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title>jQuery Validation in ASP.NET Master Page</title> <script src="Scripts/jquery-1.3.2.js" type="text/javascript"></script> <script src="Scripts/jquery-1.3.2-vsdoc2.js" type="text/javascript"></script> <script src="Scripts/jquery.validate.js" type="text/javascript"></script> <asp:ContentPlaceHolder id="head" runat="server"> </asp:ContentPlaceHolder> </head> <body> <form id="form1" runat="server"> <div> <asp:ContentPlaceHolder id="ContentPlaceHolder1" runat="server"> </asp:ContentPlaceHolder> </div> </form> </body> </html> my content page: <%@ Page Title="" Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %> <asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server"> </asp:Content> <asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server"> <script type="text/javascript"> $(document).ready(function() { $("#aspnetForm").validate({ rules: { <%=txtName.UniqueID %>: { minlength: 2, required: true }, <%=txtEmail.UniqueID %>: { required: true, email:true } }, messages: { <%=txtName.UniqueID %>:{ required: "* Required Field *", minlength: "* Please enter atleast 2 characters *" } } }); }); </script> Name: <asp:TextBox ID="txtName" MaxLength="30" runat="server" /><br /> Email: <asp:TextBox ID="txtEmail" runat="server"></asp:TextBox><br /> <asp:Button ID="btnSubmit" runat="server" onclick="SubmitTheForm();" Text="Submit" /> </asp:Content> function SubmitTheForm() { SaveTheForm(); } function SaveTheForm() { debugger; var request = buildNewContactRequest(); ContactServiceProxy.invoke({ serviceMethod: "PostNewContact", data: { request: request }, callback: function(response) { processCompletedContactStore(response); }, error: function(xhr, errorMsg, thrown) { postErrorAndUnBlockUI(xhr, errorMsg, thrown); } }); return false; }

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