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  • Text box loses focus when DIV is hovered

    - by Konoplianko
    Hello. I have a problem: When I enter a text into suggestion text box, popup panel appears. But when user places mouse over this popup panel with suggestions - text box loses focus. What should I do to prevent losing focus ? Example which have the same behaviour: http://demo.raibledesigns.com/gwt-autocomplete/ Thanks for any help. Update 1 SuggestionMenu which is being shown is extending MenuBar which sets focus for all menu items. void itemOver(MenuItem item, boolean focus) { if (item == null) { // Don't clear selection if the currently selected item's menu is showing. if ((selectedItem != null) && (shownChildMenu == selectedItem.getSubMenu())) { return; } } // Style the item selected when the mouse enters. selectItem(item); if (focus) { focus(); } // If child menus are being shown, or this menu is itself // a child menu, automatically show an item's child menu // when the mouse enters. if (item != null) { if ((shownChildMenu != null) || (parentMenu != null) || autoOpen) { doItemAction(item, false); } } } It's clear that i cant fix loosing focus. Now question is - how to make on pressing backspace or any key to focus on edit box? Thanks in advance

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  • Pre-populate iPhone Safari SQLite DB

    - by Matt Rogish
    I'm working with a PhoneGap app that uses Safari local storage (SQlite DB) via Javascript: http://developer.apple.com/safari/library/documentation/iPhone/Conceptual/SafariJSDatabaseGuide/UsingtheJavascriptDatabase/UsingtheJavascriptDatabase.html On first load, the app creates the database, tables, and populates the data via a series of INSERT statements. If the user closes the app while this processing is happening, then my app database is left in an inconsistent state. What I prefer to do is deploy the SQLite DB as part of my iTunes App packaging so nothing must be populated at app cold start. However, I'm not sure if that is possible -- all of the google hits for this topic that I can find are referring to the core-data provided SQLite which is not what we're using... If it's not possible, could I wrap the entire thing in a transaction and keep re-trying it when the app is restarted? Failing that, I guess I can create a simple table with one boolean column "is_app_db_loaded?" and set it to true after I've processed all my inserts. But that's really gross... Ideas? Thanks!!

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  • Collision of dot and line in 2D space

    - by Anderiel
    So i'm trying to make my first game on android. The thing is i have a small moving ball and i want it to bounce from a line that i drew. For that i need to find if the x,y of the ball are also coordinates of one dot from the line. I tried to implement these equations about lines x=a1 + t*u1 y=a2 + t*u2 = (x-a1)/u1=(y-a2)/u2 (t=t which has to be if the point is on the line) where x and y are the coordinates im testing, dot[a1,a2] is a dot that is on the line and u(u1,u2) is the vector of the line. heres the code: public boolean Collided() { float u1 =Math.abs(Math.round(begin_X)-Math.round(end_X)); float u2 =Math.abs(Math.round(begin_Y)-Math.round(end_Y)); float t_x =Math.round((elect_X - begin_X)/u1); float t_y =Math.round((elect_Y - begin_Y)/u2); if(t_x==t_y) { return true; } else { return false; } } points [begin_X,end_X] and [begin_Y,end_Y] are the two points from the line and [elect_X,elect_Y] are the coordinates of the ball theoreticaly it should work, but in the reality the ball most of the time just goes straigth through the line or bounces somewhere else where it shouldnt

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  • How should I organize complex SQL views in Rails?

    - by Benjamin Oakes
    I manage a research database with Ruby on Rails. The data that is entered is primarily used by scientists who prefer to have all the relevant information for a study in one single massive table for use in their statistics software of choice. I'm currently presenting it as CSV, as it's very straightforward to do and compatible with the tools people want to use. I've written many views (the SQL kind, not the Rails HTML/ERB kind) to make the output they expect a reality. Some of these views are quite large and have a fair amount of complexity behind them. I wrote them in SQL because there are many calculations and comparisons that are more easily done with SQL. They're currently loaded into the database straight from a file named views.sql. To get the requested data, I do a select * from my_view;. The views.sql file is getting quite large. Part of the problem is that we're still figuring out what the data we collect means, so there's a lot of changes being made to the views all the time -- and a ton of them are being created. Many of them need to be repeatable. I've recently run into issues organizing and testing these views. Rails works great for user interface stuff and business logic, but I'm not aware of much existing structure for handling the reporting we require. Some options I've thought of: Should I move them into the most relevant models somehow? Several of the views interact with each other, which makes this situation more complex than just doing a single find_by_sql, so I don't know if they should only be part of the model. Perhaps they should be treated as a "view" in the MVC sense? (That is, they could be moved into app/views/ and live alongside the HTML, perhaps as files named something like my_view.csv.sql which return CSV.) How would you deal with a complex reporting problem like this?

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  • vectorizing loops in Matlab - performance issues

    - by Gacek
    This question is related to these two: http://stackoverflow.com/questions/2867901/introduction-to-vectorizing-in-matlab-any-good-tutorials http://stackoverflow.com/questions/2561617/filter-that-uses-elements-from-two-arrays-at-the-same-time Basing on the tutorials I read, I was trying to vectorize some procedure that takes really a lot of time. I've rewritten this: function B = bfltGray(A,w,sigma_r) dim = size(A); B = zeros(dim); for i = 1:dim(1) for j = 1:dim(2) % Extract local region. iMin = max(i-w,1); iMax = min(i+w,dim(1)); jMin = max(j-w,1); jMax = min(j+w,dim(2)); I = A(iMin:iMax,jMin:jMax); % Compute Gaussian intensity weights. F = exp(-0.5*(abs(I-A(i,j))/sigma_r).^2); B(i,j) = sum(F(:).*I(:))/sum(F(:)); end end into this: function B = rngVect(A, w, sigma) W = 2*w+1; I = padarray(A, [w,w],'symmetric'); I = im2col(I, [W,W]); H = exp(-0.5*(abs(I-repmat(A(:)', size(I,1),1))/sigma).^2); B = reshape(sum(H.*I,1)./sum(H,1), size(A, 1), []); But this version seems to be as slow as the first one, but in addition it uses a lot of memory and sometimes causes memory problems. I suppose I've made something wrong. Probably some logic mistake regarding vectorizing. Well, in fact I'm not surprised - this method creates really big matrices and probably the computations are proportionally longer. I have also tried to write it using nlfilter (similar to the second solution given by Jonas) but it seems to be hard since I use Matlab 6.5 (R13) (there are no sophisticated function handles available). So once again, I'm asking not for ready solution, but for some ideas that would help me to solve this in reasonable time. Maybe you will point me what I did wrong.

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  • Python function correctly/incorrectly?

    - by Anthony Kernan
    I'm just starting too use python, learning experience. I know the basics logic of programming. I have a function in python that is running everytime, even when it's not supposed to. I use an if statement in the beginning of the function. I don't know why this if statement is not working, confused. I have another function that is similar and works correctly. Am I missing something simple? Here's the function that is not working... def check_artist_art(): if os.path.exists("/tmp/artistinfo") and open("/tmp/artistinfo").read() != title: #if artist == "": if os.path.exists(home + "/.artist"): os.remove(home + "/.artist") if os.path.exists("/tmp/artistinfo"): os.remove("/tmp/artistinfo") print artist return False else: os.path.exists("/tmp/artistinfo") and open("/tmp/artistinfo").read() == artist return False return True And this is the similar function that is working correctly.. def check_album(): if os.path.exists("/tmp/albuminfo") and open("/tmp/albuminfo").read() != album: if os.path.exists(home + "/.album"): os.remove(home + "/.album") if os.path.exists("/tmp/albuminfo"): os.remove("/tmp/albuminfo") return False elif os.path.exists("/tmp/trackinfo") and open("/tmp/trackinfo").read() == artist + album: return False return True Any help is greatly appreciated.

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  • Maven: Repository no longer exists! Now what?

    - by pek
    I have just begun my journey in Maven2 and found the dependency repositories logic a little weird... As far as I understand, I need to point Maven to a repository from which it can fetch the various POMs found in my dependencies. In other words, instead of downloading all the dependencies in my lib folder, as I did in the Ant era, I now have to look into various Maven repositories and, hopefully, find what I need. OK, thanks to MVNBrowser things get a little easier. But! What if the Maven repository no longer exists? For example, I use Slick in my project. Among the other dependencies, slick uses JNLP (for some reason). The artifact for jnlp is: <dependency> <groupId>javax.jnlp</groupId> <artifactId>jnlp</artifactId> <version>1.2</version> </dependency> According to MVNBrowser, javax.jnlp can only be found in one repository, Freehep. Which is no longer available. So now what?

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  • Disable validation in an object in Ruby on Rails

    - by J. Pablo Fernández
    I have an object which whether validation happens or not should depend on a boolean, or in another way, validation is optional. I haven't found a clean way to do it. What I'm currently doing is this (disclaimer: you cannot unsee, leave this page if you are too sensitive): def valid? if perform_validation super else super # Call valid? so that callbacks get called and things like encrypting passwords and generating salt in before_validation actually happen errors.clear # but then clear the errors true # and claim ourselves to be valid. This is super hacky! end end Any better ways? Before you point to the :if argument of many validations, this is for a user model which is using authlogic so it has a lot of validation rules. You can stop reading here if you belive me. If you don't, authlogic already sets some :ifs like: :if => :email_changed? which I have to turn into :if => Proc.new {|user| user.email_changed? and user.perform_validation} and in some other cases, since I'm also using authlogic-oid (OpenID) I just don't have control over the :if, authlogic-oid sets it in a way I cannot change it (in time) without further monkey patching. So I have to override seemingly unrelated functions, catch exceptions if a method doesn't exist, etc. The previous hacky solution if the best of my two attempts.

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  • Interchange structured data between Haskell and C

    - by Eonil
    First, I'm a Haskell beginner. I'm planning integrating Haskell into C for realtime game. Haskell does logic, C does rendering. To do this, I have to pass huge complexly structured data (game state) from/to each other for each tick (at least 30 times per second). So the passing data should be lightweight. This state data may laid on sequential space on memory. Both of Haskell and C parts should access every area of the states freely. In best case, the cost of passing data can be copying a pointer to a memory. In worst case, copying whole data with conversion. I'm reading Haskell's FFI(http://www.haskell.org/haskellwiki/FFICookBook#Working_with_structs) The Haskell code look specifying memory layout explicitly. I have a few questions. Can Haskell specify memory layout explicitly? (to be matched exactly with C struct) Is this real memory layout? Or any kind of conversion required? (performance penalty) If Q#2 is true, Any performance penalty when the memory layout specified explicitly? What's the syntax #{alignment foo}? Where can I find the document about this? If I want to pass huge data with best performance, how should I do that? *PS Explicit memory layout feature which I said is just C#'s [StructLayout] attribute. Which is specifying in-memory position and size explicitly. http://www.developerfusion.com/article/84519/mastering-structs-in-c/ I'm not sure Haskell has matching linguistic construct matching with fields of C struct.

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  • Work around for MessageNotReadableException in Java

    - by Hari
    Hi, I am building a small api around the JMS API for a project of mine. Essentially, we are building code that will handle the connection logic, and will simplify publishing messages by providing a method like Client.send(String message). One of the ideas being discussed right now is that we provide a means for the users to attach interceptors to this client. We will apply the interceptors after preparing the JMS message and before publishing it. For example, if we want to timestamp a message and wrote an interceptor for that, then this is how we would apply that ...some code ... Message message = session.createMessage() ..do all the current processing on the message and set the body for(interceptor:listOfInterceptors){ interceptor.apply(message) } One of the intrerceptors we though of was to compress the message body. But when we try to read the body of the message in the interceptor, we are getting a MessageNotReadableException. In the past, I normally compressed the content before setting it as the body of the message - so never had to worry about this exception. Is there any way of getting around this exception?

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  • Serialized NHibernate Configuration objects - detect out of date or rebuild on demand?

    - by fostandy
    I've been using serialized nhibernate configuration objects (also discussed here and here) to speed up my application startup from about 8s to 1s. I also use fluent-nhibernate, so the path is more like ClassMap class definitions in code fluentconfiguration xml nhibernate configuration configuration serialized to disk. The problem from doing this is that one runs the risk of out of date mappings - if I change the mappings but forget to rebuild the serialized configuration, then I end up using the old mappings without realising it. This does not always result in an immediate and obvious error during testing, and several times the misbehaviour has been a real pain to detect and fix. Does anybody have any idea how I would be able to detect if my classmaps have changed, so that I could either issue an immediate warning/error or rebuild it on demand? At the moment I am comparing timestamps on my compiled assembly against the serialized configuration. This will pickup mapping changes, but unfortunately it generates a massive false positive rate as ANY change to the code results in an out of date flag. I can't move the classmaps to another assembly as they are tightly integrated into the business logic. This has been niggling me for a while so I was wondering if anybody had any suggestions?

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  • Adding <tr> from repeater's ItemDataBound Event

    - by nemiss
    My repeater's templates generate a table, where each item is a table row. When a very very specific condition is met (itemdata), I want to add an additional row to the table from this event. How can I do that? protected void rptData_ItemDataBound(object sender, RepeaterItemEventArgs e) { if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) { bool tmp = bool.Parse(DataBinder.Eval(e.Item.DataItem, "somedata").ToString()); if (!tmp && e.Item.ItemIndex != 0) { //Add row after this item } } } I can use e.Item.Controls.Add() and add TableRow but for that I need to locate a table right? How can I solve that? UPDATE I will explain now why I need this: I am creating a sort of message board, where data entries are displayed in a tabled style. The first items in the table are "important" items after those items, i want to add this row. I could solved it using 2 repeaters, where the first repeater will be bounded to pinned items, and the second repeater will be bounded to refular items. But I don't want to have to repeaters nor I want to complex the business logic for separating the fetched data to pinned and not-pinned collection. I think the best opton is to do it "onfly", using one repeater and one datasource.

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  • Django unit testing: South-migrated DB works in MySQL, throws duplicate PK error in PostGreSQL. Am I

    - by unclaimedbaggage
    Hi folks, (Worth starting off with a disclaimer: I'm very new to PostGreSQL) I have a django site which involves a standard app/tests.py testing file. If I migrate the DB to MySQL (through South),, the tests all pass. However in PostGresQL, I'm getting the following error: IntegrityError: duplicate key value violates unique constraint "business_contact_pkey" Note this happens while unit testing only - the actual page runs fine in both MySQL & PostGresql. Really having a heckuva time figuring this one out. Anyone have ideas? Below are the Postgresql "\d business_contact" & offending tests.py method if they help. No changes made to either DB except the (same) South migrations Thanks first_name | character varying(200) | not null mobile_phone | character varying(100) | surname | character varying(200) | not null business_id | integer | not null created | timestamp with time zone | not null deleted | boolean | not null default false updated | timestamp with time zone | not null slug | character varying(150) | not null phone | character varying(100) | email | character varying(75) | id | integer | not null default nextval('business_contact_id_seq'::regclass) Indexes: "business_contact_pkey" PRIMARY KEY, btree (id) "business_contact_slug_key" UNIQUE, btree (slug) "business_contact_business_id" btree (business_id) Foreign-key constraints: "business_id_refs_id_772cc1b7b40f4b36" FOREIGN KEY (business_id) REFERENCES business(id) DEFERRABLE INITIALLY DEFERRED Referenced by: TABLE "business" CONSTRAINT "primary_contact_id_refs_id_dfaf59c4041c850" FOREIGN KEY (primary_contact_id) REFERENCES business_contact(id) DEFERRABLE INITIALLY DEFERRED TEST DEF: def test_add_business_contact(self): """ Add a business contact """ contact_slug = 'test-new-contact-added-new-adf' business_id = 1 business = Business.objects.get(id=business_id) postdata = { 'first_name': 'Test', 'surname': 'User', 'business': '1', 'slug': contact_slug, 'email': '[email protected]', 'phone': '12345678', 'mobile_phone': '9823452', 'business': 1, 'business_id': 1, } #Test to ensure contacts that should not exist are not returned contact_not_exists = Contact.objects.filter(slug=contact_slug) self.assertFalse(contact_not_exists) #Add the contact and ensure it is present in the DB afterwards """ contact_add_url = '%s%s/contact/add/' % (settings.BUSINESS_URL, business.slug) self.client.post(contact_add_url, postdata) added_contact = Contact.objects.filter(slug=contact_slug) print added_contact try: self.assertTrue(added_contact) except: formset = ContactForm(postdata) print formset.errors self.assertFalse(True, "Contact not found in the database - most likely, the post values in the test didn't validate against the form")

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  • Is there a default way to get hold of an internal property in jQueryUi widget?

    - by prodigitalson
    Im using an existing widget from the jquery-ui labs call selectmenu. It has callback options for the events close and open. The problem is i need in these event to animate a node that is part of the widget but not what its connected to. In order to do this i need access to this node. for example if i were to actually modify the widget code itself: // ... other methods/properties "open" : function(event){ // ... the original logic // this is my animation $(this.list).slideUp('slow'); // this is the orginal call to _trigger this._trigger('open', event, $this._uiHash()); }, // ... other methods/properties However when in the scope of the event handler i attach this is the orginal element i called the widget on. I need the widget instance or specifically the widget instance's list property. $('select#custom').selectmenu({ 'open': function(){ // in this scope `this` is an HTMLSelectElement not the ui widget } }); Whats the best way to go about getting the list property from the widget?

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  • Searching with MATCH(), AGAINST() and AS score with mysqli and php

    - by Drew
    Below is the code I am using to search my table. I have made the relevant columns FULLTEXT in the table. This doesn't return me anything. Can someone tell me what it is that i'm doing wrong? Thanks in advance. $sql = 'SELECT id,uname,class,school, MATCH(uname, class, school) AGAINST(?) AS score FROM images WHERE MATCH(uname, class, school) AGAINST(? IN BOOLEAN MODE) ORDER BY score DES'; $stmt = $db_connection->prepare($sql); $stmt->bind_param('ss',$keyword,$keyword); $stmt->execute(); $stmt->store_result(); $stmt->bind_result($id,$uname,$class,$school); $xml = "<data>".PHP_EOL; while($stmt->fetch()){ $xml .= " <person>".PHP_EOL; $xml .= " <id>$id</id>".PHP_EOL; $xml .= " <name>$uname</name>".PHP_EOL; $xml .= " <class>$class</class>".PHP_EOL; $xml .= " <school>$school</school>".PHP_EOL; $xml .= " </person>".PHP_EOL; } $xml .= "</data>"; echo $xml; Below is an image of the indexes of the table:

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  • List local printers

    - by vladimir
    hi all, i am using this routine to list the local printers installed on on a machine... var p: pointer; hpi: _PRINTER_INFO_2A; hGlobal: cardinal; dwNeeded, dwReturned: DWORD; bFlag: boolean; i: dword; begin p := nil; EnumPrinters(PRINTER_ENUM_LOCAL, nil, 2, p, 0, dwNeeded, dwReturned); if (dwNeeded = 0) then exit; GetMem(p,dwNeeded); if (p = nil) then exit; bFlag := EnumPrinters(PRINTER_ENUM_LOCAL, nil, 2, p, dwneeded, dwNeeded, dwReturned); if (not bFlag) then exit; CbLblPrinterPath.Properties.Items.Clear; for i := 0 to dwReturned - 1 do begin CbLblPrinterPath.Properties.Items.Add(TPrinterInfos(p^)[i].pPrinterName); end; FreeMem(p); TPrinterInfos(p^)[i].pPrinterName returns a 'P' for printer name. i have a PdfCreator installed as a printer. TPrinterInfos is an array of _PRINTER_INFO_2A. how can i fix this?

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  • Android Maven and Refresh Problem

    - by antonio Musella
    Hi all, i've a strange problem with maven and android I've 3 maven project and 2 normal java maven project divided in this manner : normal project : model project ... packaged as jar ... contains java Pojo Bean and Interface. Dao Project ... packaged as jar ... contains Db Logic - Depend on model Project Android Application Maven project ContentProvider ... packaged as apk ... contains ContentProviders only. Depends on Dao Project Editors ... packaged as apk ... contains only Editor, Depends on Dao project MainApp ... packaged as apk ... contains MyApp, Depends on DAO ... The Problem is that if i modify DAO Project , Then do a maven clean and maven install of all apk project, then run as Android Application within Eclipse, i don't see updated app on my Emulator. Nicely if i shut down my ubuntu workstation and restart it i can see The updated app on my Emulator. Do you know a solution for this issue ? thanks and regards

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  • Determining polygon intersection and containment

    - by Victor Liu
    I have a set of simple (no holes, no self-intersections) polygons, and I need to check that they don't intersect each other (one can be entirely contained in another; that is okay). I can check this by simply checking the per-vertex inside-ness of one polygon versus other polygons. I also need to determine the containment tree, which is the set of relationships that say which polygon contains any given polygon. Since no polygon can intersect any other, then any contained polygon has a unique container; the "next-bigger" one. In other words, if A contains B contains C, then A is the parent of B, and B is the parent of C, and we don't consider A the parent of C. The question: How do I efficiently determine the containment relationships and check the non-intersection criterion? I ask this as one question because maybe a combined algorithm is more efficient than solving each problem separately. The algorithm should take as input a list of polygons, given by a list of their vertices. It should produce a boolean B indicating if none of the polygons intersect any other polygon, and also if B = true, a list of pairs (P, C) where polygon P is the parent of child C. This is not homework. This is for a hobby project I am working on.

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  • Comparing all properties of an object using expression trees

    - by stringargs
    Hi, I'm trying to write a simple generator that uses an expression tree to dynamically generate a method that compares all properties of an instance of a type to the properties of another instance of that type. This works fine for most properties, like int an string, but fails for DateTime? (and presumably other nullable value types). The method: static Delegate GenerateComparer(Type type) { var left = Expression.Parameter(type, "left"); var right = Expression.Parameter(type, "right"); Expression result = null; foreach (var p in type.GetProperties()) { var leftProperty = Expression.Property(left, p.Name); var rightProperty = Expression.Property(right, p.Name); var equals = p.PropertyType.GetMethod("Equals", new[] { p.PropertyType }); var callEqualsOnLeft = Expression.Call(leftProperty, equals, rightProperty); result = result != null ? (Expression)Expression.And(result, callEqualsOnLeft) : (Expression)callEqualsOnLeft; } var method = Expression.Lambda(result, left, right).Compile(); return method; } On a DateTime? property it fails with: Expression of type 'System.Nullable`1[System.DateTime]' cannot be used for parameter of type 'System.Object' of method 'Boolean Equals(System.Object)' OK, so it finds an overload of Equals that expects object. So why can't I pass a DateTime? into that, as it's convertible to object? If I look at Nullable<T>, it indeed has an override of Equals(object o). PS: I realize that this isn't a proper generator yet as it can't deal with null values, but I'll get to that :)

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  • Which languages and techniques can I use to improve my coding practices?

    - by Danjah
    I've been offered the opportunity upskill through study, while at work which is great. My background I am mostly self-taught, but have worked with many excellent people over the years - both self-taught and fully educated, and on many decent projects. I have mild experience in Actionscript, I'm getting better every day with my Javascript, and my CSS is angled at best practice, but needs a bit of modernising. I'm a traditional interface developer, I'm not stupid and I like a challenge. My goal I need to start seeing ways of applying better logic, optimising code, refactoring, different styles of development (agile, others?), and.. well I need to try and start thinking like.. a more solid programmer. Its hard to describe, I have good solutions and I'm efficient - but I KNOW that there's a bunch I am missing. I am already employed with a solid career, but I feel the need to fill gaps. My question/s Are there a set of guiding principles you can recommend I focus on to improve the points above? Are there particular programming languages which I might focus on to get a broader overview? Do you think I should avoid particular styles of development, or even languages, while solidifying what might end up being part 'the basics' but hopefully 'advanced programming'? -- Sorry if this appears off topic or something but I figure you're probably some of the best people to ask.

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  • Closures in Ruby

    - by Isaac Cambron
    I'm kind of new to Ruby and some of the closure logic has me a confused. Consider this code: array = [] for i in (1..5) array << lambda {j} end array.map{|f| f.call} => [5, 5, 5, 5, 5] This makes sense to me because i is bound outside the loop, so the same variable is captured by each trip through the loop. It also makes sense to me that using an each block can fix this: array = [] (1..5).each{|i| array << lambda {i}} array.map{|f| f.call} => [1, 2, 3, 4, 5] ...because i is now being declared separately for each time through. But now I get lost: why can't I also fix it by introducing an intermediate variable? array = [] for i in 1..5 j = i array << lambda {j} end array.map{|f| f.call} => [5, 5, 5, 5, 5] Because j is new each time through the loop, I'd think a different variable would be captured on each pass. For example, this is definitely how C# works, and how -- I think-- Lisp behaves with a let. But in Ruby not so much. It almost looks like = is aliasing the variable instead of copying the reference, but that's just speculation on my part. What's really happening?

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  • Why should I override hashCode() when I override equals() method?

    - by Bragaadeesh
    Ok, I have heard from many places and sources that whenever I override the equals() method, I need to override the hashCode() method as well. But consider the following piece of code package test; public class MyCustomObject { int intVal1; int intVal2; public MyCustomObject(int val1, int val2){ intVal1 = val1; intVal2 = val2; } public boolean equals(Object obj){ return (((MyCustomObject)obj).intVal1 == this.intVal1) && (((MyCustomObject)obj).intVal2 == this.intVal2); } public static void main(String a[]){ MyCustomObject m1 = new MyCustomObject(3,5); MyCustomObject m2 = new MyCustomObject(3,5); MyCustomObject m3 = new MyCustomObject(4,5); System.out.println(m1.equals(m2)); System.out.println(m1.equals(m3)); } } Here the output is true, false exactly the way I want it to be and I dont care of overriding the hashCode() method at all. This means that hashCode() overriding is an option rather being a mandatory one as everyone says. I want a second confirmation.

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  • Is there a better way to write this LINQ query?

    - by Raj Aththanayake
    Hi Is there a better simplified way to write this query. My logic is if collection contains customer ids and countrycodes, do the query ordey by customer id ascending. If there are no contain id in CustIDs then do the order by customer name. Is there a better way to write this query? I'm not really familiar with complex lambdas. var custIdResult = (from Customer c in CustomerCollection where (c.CustomerID.ToLower().Contains(param.ToLower()) && (countryCodeFilters.Any(item => item.Equals(c.CountryCode))) ) select c).ToList(); if (custIdResult.Count > 0) { return from Customer c in custIdResult where ( c.CustomerName.ToLower().Contains(param.ToLower()) && countryCodeFilters.Any(item => item.Equals(c.CountryCode))) orderby c.CustomerID ascending select c; } else { return from Customer c in CustomerCollection where (c.CustomerName.ToLower().Contains(param.ToLower()) && countryCodeFilters.Any(item => item.Equals(c.CountryCode))) orderby c.CustomerName descending select c; }

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  • Scala newbie vproducer/consumer attempt running out of memory

    - by Nick
    I am trying to create a producer/consumer type Scala app. The LoopControl just sends a message to the MessageReceiver continually. The MessageReceiver then delegates work to the MessageCreatorActor (whose work is to check a map for an object, and if not found create one and start it up). Each MessageActor created by this MessageCreatorActor is associated with an Id. Eventually this is where I want to do business logic. But I run out of memory after 15 minutes. Its finding the cached actors,but quickly runs out of memory. Any help is appreciated. Or any one has any good code on producers consumers doing real stuff (not just adding numbers), please post. import scala.actors.Actor import java.util.HashMap import scala.actors.Actor._ case object LoopControl case object MessageReceiver case object MessageActor case object MessageActorCreator class MessageReceiver(msg: String) extends Actor { var messageActorMap = new HashMap[String, MessageActor] val messageCreatorActor = new MessageActorCreator(null, null) def act() { messageCreatorActor.start loop { react { case MessageActor(messageId) => if (msg.length() > 0) { var messageActor = messageActorMap.get(messageId); if(messageActor == null) { messageCreatorActor ! MessageActorCreator(messageId, messageActorMap) }else { messageActor ! MessageActor } } } } } } case class MessageActorCreator(msg:String, messageActorMap: HashMap[String, MessageActor]) extends Actor { def act() { loop { react { case MessageActorCreator(messageId, messageActorMap) => if(messageId != null ) { var messageActor = new MessageActor(messageId); messageActorMap.put(messageId, messageActor) println(messageActorMap) messageActor.start messageActor ! MessageActor } } } } } class LoopControl(messageReceiver:MessageReceiver) extends Actor { var count : Int = 0; def act() { while (true) { messageReceiver ! MessageActor ("00-122-0X95-FEC0" + count) //Thread.sleep(100) count = count +1; if(count > 5) { count = 0; } } } } case class MessageActor(msg: String) extends Actor { def act() { loop { react { case MessageActor => println() println("MessageActor: Got something-> " + msg) } } } } object messages extends Application { val messageReceiver = new MessageReceiver("bootstrap") val loopControl = new LoopControl(messageReceiver) messageReceiver.start loopControl.start }

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  • Flexible forms and supporting database structure

    - by sunwukung
    I have been tasked with creating an application that allows administrators to alter the content of the user input form (i.e. add arbitrary fields) - the contents of which get stored in a database. Think Modx/Wordpress/Expression Engine template variables. The approach I've been looking at is implementing concrete tables where the specification is consistent (i.e. user profiles, user content etc) and some generic field data tables (i.e. text, boolean) to store non-specific values. Forms (and model fields) would be generated by first querying the tables and retrieving the relevant columns - although I've yet to think about how I would setup validation. I've taken a look at this problem, and it seems to be indicating an EAV type approach - which, from my brief research - looks like it could be a greater burden than the blessings it's flexibility would bring. I've read a couple of posts here, however, which suggest this is a dangerous route: How to design a generic database whose layout may change over time? Dynamic Database Schema I'd appreciate some advice on this matter if anyone has some to give regards SWK

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