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  • jQuery.data() works in Mac OS WebKit, but not on iPhone OS?

    - by rpj
    I'm playing around with jQTouch for an iPhone OS app that I've been toying with off and on for a while. I wanted to try my hand building it as a web app so I started playing with jQTouch. For reference, here is the page+source (all my code is currently in index.html so you can just "View Source" to see it all): http://rpj.me/doughapp.com/wd/ Essentially, I'm trying to save pertinent JSON objects retrieved from Google Local into DOM objects using the data() method (in this example, obj is the Google Local object): $('#locPane').data('selected', obj); then later (in a different "pane"), retrieving that object to be used: $('#locPane').bind('pageAnimationEnd', function(e, inf) { var selobj = $(this).data('selected'); // use 'selobj' here ... } In Chromium and Safari on the desktop OS (Snow Leopard in my case), this works perfectly (try it out). However, the same code returns undefined for the call to $(this).data('selected') in the second snippet above. I've also tried $('#' + e.target.id).data('selected') and even the naive $('#locPane').data('selected'). All variants return undefined in the iPhone OS version of WebKit, but not on the desktop. Interestingly, the running this on Mobile Safari in the iPhone Simulator fails as well. If you look at the full source, you'll see that I even try to save this object into my global jQTouch object (named jqt in my code). This, too, fails on the mobile platform. Has anyone else ever ran into this? I'll admit to not being a web/javascript programmer by trade, so if I'm making an idiot's error please call me out on it. Thank you in advance for the help! -RPJ Update: I didn't make it clear in the original post, but I'm open to any workaround if it works consistently. Since I'm having trouble storing these objects in general, anything that allows me to keep them around is good enough for now. Thanks!

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  • How do you make use of the provider independency in the Entity Framework?

    - by Anders Svensson
    I'm trying to learn more about data access and the Entity Framework. My goal is to have a "provider independent" data access layer (to be able to switch easily e.g. from SQL Server to MySQL or vice versa), and since the EF is supposed to be provider independent it seems like a good way to go. But how do you use this provider independence? I mean, I was expecting to be able to sort of "program to an interface", and then just be able to switch database provider. But as far as I can tell I'm only getting a concrete type to program against, an "Entities" class, e.g. in my case it is: UserDBEntities _context = new UserDBEntities(); What I would have expected to be able to switch provider easily was to have an interface e.g. like IEntities _context = new UserDBEntities(); Sort of like I can do with datasets... But maybe that isn't how it works at all with EF? Or do you just switch provider in the connectionstring, and the model stays the same?? Please remember that I'm a complete newbie at this EF, and rather inexperienced with databases in general, so I would really appreciate if you could be as clear as possible :-)

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  • xpath query to find parent tag

    - by cru3l
    for example, i have this xml <elements> <a> <b>6</b> <b>5</b> <b>6</b> </a> <a> <b>5</b> <b>5</b> <b>6</b> </a> <a> <b>5</b> <b>5</b> <b>5</b> <b>5</b> </a> </elements> i need a xpath query, which must return me parent tag, only if all its children are equal to 5 (a[3] in this case). Something like that //b[text()="5"]/.. but with check of all children's tags. Please note that number of children tags can be different from node to node. It's possible with only xpath query? thanks

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  • Connecting grouped dots/points on a scatter plot based on distance

    - by ToNoY
    I have 2 sets of depth point measurements, for example: > a depth value 1 2 2 2 4 3 3 6 4 4 8 5 5 16 40 6 18 45 7 20 58 > b depth value 1 10 10 2 12 20 3 14 35 I want to show both groups in one figure plotted with depth and with different symbols as you can see here plot(a$value, a$depth, type='b', col='green', pch=15) points(b$value, b$depth, type='b', col='red', pch=14) The plot seems okay, but the annoying part is that the green symbols are all connected (though I want connected lines also). I want connection only when one group has a continued data points at 2 m interval i.e. the symbols should be connected with a line from 2 to 8 m (green) and then group B symbols should be connected from 10-14 m (red) and again group A symbols should be connected (green), which means I do NOT want to see the connection between 8 m sample with the 16 m for group A. An easy solution may be dividing the group A into two parts (say, A-shallow and A-deep) and then plotting A-shallow, B, and A-deep separately. But this is completely impractical because I have thousands of data points with hundreds of groups i.e. I have to produce many depth profiles. Therefore, there has to be a way to program so that dots are NOT connected beyond a prescribed frequency/depth interval (e.g. 2 m in this case) for a particular group of samples. Any idea?

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  • Circumvent c++ null-terminated string frustration

    - by ypnos
    I'm using boost::program_options and it suffers from the same as many other c++ libs, even std itself: It still uses C-style null-terminated strings, because nobody really likes the weak std::string. The method in question is: options_description_easy_init& operator()(const char* name, const value_semantic* s, const char* description); The typical use case is just fine: options.add_options() ("graphical", bool_switch(&isGraphical)->default_value(false), "Show any graphical output during runtime") However, I need the name of the option to be set dynamically. The reason is that in some cases I nead a custom prefix, which is added to the string by my function std::string key(const std::string& k): options.add_options() (key("graphical"), bool_switch(&isGraphical)->default_value(false), "Show any graphical output during runtime") This fails. I could now use c_str() on the std::string but that's evil -- I don't know how long program_options keeps the variable around and if my string is still alive when needed. I could also reserve memory in a buffer etc. and hand in that. The buffer is never freed and it sucks/is evil. Is there anything else I can do to circumvent the C-style string mess in this situation?

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  • Best way to parse this particular string using awk / sed?

    - by Jack
    Hi, I need to get a particular version string from a file (call it version.lst) and use it to compare another in a shell script. For example sake, the file contains lines that look like this: V1.000 -- build date and other info here -- APP1 V1.000 -- build date and other info here -- APP2 V1.500 -- build date and other info here -- APP3 .. and so on. Let's say I am trying to grab the first version (in this case, V1.000) from APP1. Obviously, the versions can change and I want this to be dynamic. What I have right now works: var = `cat version.lst | grep " -- APP1" | grep -Eo V[0-9].[0-9]{3}` Pipe to grep will get the line containing APP1 and the second pipe to grep will get the version string. However, I hear grep is not the way to do this so I'd like to learn the best way using awk or sed. Any ideas? I am new to both and haven't found a tutorial easy enough to learn the syntax of it. Do they support egrep? Thanks!

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  • Managing My Database in Source Control

    - by Jason
    As I am working with a new database project (within VS2008), and as I have never developed a database from scratch, I immediately began looking into how to manage a database within source control (in this case, Subversion). I found some information on SO, including this post: Keeping development databases in multiple environments in sync. One of the answers in particular pointed to a number of a links, all of which had good, useful information. I was reading a series of posts by K. Scott Allen which describe how he manages database change. From my reading (and please pardon the noobishness of my question), it seems as though the database itself is never checked into a repository. Rather, scripts that can build the database, along with test data (which is also populated from scripts) is checked into the repository. Ultimately, this means that, when a developer is testing his or her app, these scripts, which are part of the build process, are run. This ensures that the database is up-to-date, but is also run locally from every developer's machine. This makes sense to me (if I am indeed reading that correctly). However, if I am missing something, I would appreciate correction or additional guidance. In addition, another question I wanted to ask - does this also mean that I should NOT check in the mdf or ldf files that are created from Visual Studio? Thanks for any help and additional insight. Always appreciated.

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  • Why represent shopping carts and order invoices differently in a domain model?

    - by Todd
    I've built some shopping cart systems in the past, but I always designed them such that the final order invoice is just a shopping cart that has been marked as "purchased". All the logic for adding/removing/changing items in a cart is also the logic for the order. All data is stored in the same tables in the database. But it seems this is not the proper way to design an e-commerce site.. Can someone explain the benefit of separating the shopping cart from invoices in the domain model? It seems to me this would lead to a lot of duplicated code, an extra set of tables in the database, and make it harder to maintain in the event the system need to start accommodating more complicated orders (like specifying selected options for an item which may or may not change the price/availability/shipping time of the order). I'm assuming I just haven't seen the light, as every book and other example I see seems to separate these two seemingly similar concerns -- but I can't find any explanation as to the benefit of doing such! It's also the case in the systems that I design that changes are often made after the initial order is confirmed. It's not uncommon for items to be removed, replaced, or added afterwards (but prior to fulfillment).

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  • is it better to query database or grab from file? php & mysql

    - by pfunc
    I am keeping a large amount of words in a database that I want to match up articles to. I was thinking that it would just be better to keep these words in an array and grab that array whenever needed instead of querying the database every time (since the words won't be changing that much). Is there much performance difference in doing this? And if I were to do this, how to I write a script that writes the array to a a new php file. I tried writing the array like so: while( $row = mysql_fetch_assoc($query)) { $newArray[] = $row; } $fp = fopen('noWordsArr.php', 'w'); fwrite($fp, $newArray); fclose($fp); But all I get in the other file is "Array". So i figured I could write this and then write have a chron hit up the file every few days or so in case things have changed. But I guess if there is no performance advantage then it prob won't be necessary and I can just query the database every time I need to access the words.

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  • PHP Mailer Class - Securing Email Credentials

    - by Alan A
    I am using the php mailer class to send email via my scripts. The structure is as follows: $mail = new PHPMailer; $mail->IsSMTP(); // Set mailer to use SMTP $mail->Host = 'myserver.com'; // Specify main and backup server $mail->SMTPAuth = true; // Enable SMTP authentication $mail->Username = '[email protected]'; // SMTP username $mail->Password = 'user123'; // SMTP password $mail->SMTPSecure = 'pass123'; It seems to me to be a bit of a security hole having the mailbox credentials in plain view. So I thought I might put these in an external file outside of the web root. My question is how would I then assign the $mail object these values. I of course no how to use include and/or requires... would it simple be a case of.... $mail->IsSMTP(); // Set mailer to use SMTP $mail->Host = 'myserver.com'; // Specify main and backup server $mail->SMTPAuth = true; // Enable SMTP authentication includes '../locationOutsideWebroot/emailCredntials.php'; $mail->SMTPSecure = 'pass123'; Then emailCredentails.php: <?php $mail->Username = '[email protected]'; $mail->Password = 'user123'; ?> Would this be sufficient and secure enough? Thanks, Alan.

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  • How to convert a rectangle to TRBL CSS rect value?

    - by VLostBoy
    I'm not quite sure how to put this, but here goes... The css clip attribute is defined like so: rect(top, right, bottom, left). However, I'm exploring the use of a custom Rectangle 'class' to encapsulate some operations. The rectangle class has the attributes height, width and x, y. The x and y values are encapsulated in a Point object, and the height and width are encapsulated in a Dimension object, the rectangle being a composite of a point (its top-left location) and a dimension (width and height). So far so good. I though it would be pretty simple on the basis of having the rectangles x, y, width and height values to define the css rect attribute in terms of top, right, bottom, left, but I've become hopelessly confused- I've been googling for a while, and I can't seem to find any documentation as to what the TRBL values actually are or what they represent. For example, should I be thinking in terms of co-ordinates, in which case, surely I can describe the rectangle as a css rect using the rectangles x position for Top, x position + width for Right, the rectangles height + y for Bottom and its y position for Left... but thats a load of BS, surely? Also, surely rect is actually an inset, or have I just inverted my understanding of clip? I'd appreciate some advice. What I want to be able to do is (i) Define a rectangle using x, y, width and height (ii)Express the rectangle in TRBL form so that I can manipulate a divs clipping behaviour (iii)Change x, y, width or height and recalculate in terms of TRBL and goto (ii) I appreciate there are some other factors here, and some intermediary transforms to be done, but I've confused myself pretty badly- Can anyone give me some pointers?

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  • HTML5 on iPhone Safari - data stored by localStorage does not always persist. Why?

    - by Aerodyne
    Hi, I write a simple iPhone web app using HTML5's localStorage. Tests on a 2G device show that data stored using localStorage does not persist after the Safari process is killed although the opened Safari windows are remembered. The data is also lost in a case where I am on a different site on a different Safari window, then I change the window to where the web app in subject is shown. When Safari loads the page it automatically refreshes the page. Then the data is lost. This is a simple test code: <html> <head> <meta name="viewport" content="height=device-height, width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" /> </head> <body> <script> alert("1:" + localStorage.getItem("test")); localStorage.setItem("test", "123"); alert("2:" + localStorage.getItem("test")); </script> </body> As far as I understand the data should persist! Can anyone shed some light on this behavior? What should I do to get the persistence to work? Thanks! Tom.

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  • Time complexity of a powerset generating function

    - by Lirik
    I'm trying to figure out the time complexity of a function that I wrote (it generates a power set for a given string): public static HashSet<string> GeneratePowerSet(string input) { HashSet<string> powerSet = new HashSet<string>(); if (string.IsNullOrEmpty(input)) return powerSet; int powSetSize = (int)Math.Pow(2.0, (double)input.Length); // Start at 1 to skip the empty string case for (int i = 1; i < powSetSize; i++) { string str = Convert.ToString(i, 2); string pset = str; for (int k = str.Length; k < input.Length; k++) { pset = "0" + pset; } string set = string.Empty; for (int j = 0; j < pset.Length; j++) { if (pset[j] == '1') { set = string.Concat(set, input[j].ToString()); } } powerSet.Add(set); } return powerSet; } So my attempt is this: let the size of the input string be n in the outer for loop, must iterate 2^n times (because the set size is 2^n). in the inner for loop, we must iterate 2*n times (at worst). 1. So Big-O would be O((2^n)*n) (since we drop the constant 2)... is that correct? And n*(2^n) is worse than n^2. if n = 4 then (4*(2^4)) = 64 (4^2) = 16 if n = 100 then (10*(2^10)) = 10240 (10^2) = 100 2. Is there a faster way to generate a power set, or is this about optimal?

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  • django multiprocess problem

    - by iKiR
    I have django application, running under lighttpd via fastcgi. FCGI running script looks like: python manage.py runfcgi socket=<path>/main.socket method=prefork \ pidfile=<path>/server.pid \ minspare=5 maxspare=10 maxchildren=10 maxrequests=500 \ I use SQLite. So I have 10 proccess, which all work with the same DB. Next I have 2 views: def view1(request) ... obj = MyModel.objects.get_or_create(id=1) obj.param1 = <some value> obj.save () def view2(request) ... obj = MyModel.objects.get_or_create(id=1) obj.param2 = <some value> obj.save () And If this views are executed in two different threads sometimes I get MyModel instance in DB with id=1 and updated either param1 or param2 (BUT not both) - it depends on which process was the first. (of course in real life id changes, but sometimes 2 processes execute these two views with same id) The question is: What should I do to get instance with updated param1 and param2? I need something for merging changes in different processes. One decision is create interprocess lock object but in this case I will get sequence executing views and they will not be able to be executed simultaneously, so I ask help

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  • Strange befaviour of spring transaction support for JPA + Hibernate +@Transactional annotation

    - by abovesun
    I found out really strange behavior on relatively simple use case, probably I can't understand it because of not deep knowledges of spring @Transactional nature, but this is quite interesting. I have simple User dao that extends spring JpaDaoSupport class and contains standard save method: @Transactional public User save(User user) { getJpaTemplate().persist(user); return user; } If was working fine until I've add new method to same class: User getSuperUser(), this method should return user with isAdmin == true, and if there is no super user in db, method should create one. Thats how it was looking like: public User createSuperUser() { User admin = null; try { admin = (User) getJpaTemplate().execute(new JpaCallback() { public Object doInJpa(EntityManager em) throws PersistenceException { return em.createQuery("select u from UserImpl u where u.admin = true").getSingleResult(); } }); } catch (EmptyResultDataAccessException ex) { User admin = new User('login', 'password'); admin.setAdmin(true); save(admin); // THIS IS THE POINT WHERE STRANGE THING COMING OUT } return admin; } As you see code is strange forward and I was very confused when found out that no transaction was created and committed on invocation of save(admin) method and no new user wasn't actually created despite @Transactional annotation. In result we have situation: when save() method invokes from outside of UserDAO class - @Transactional annotation counted and user successfully created, but if save() invokes from inside of other method of the same dao class - @Transactional annotation ignored. Here how I was change save() method to force it always create transaction. public User save(User user) { getJpaTemplate().execute(new JpaCallback() { public Object doInJpa(EntityManager em) throws PersistenceException { em.getTransaction().begin(); em.persist(user); em.getTransaction().commit(); return null; } }); return user; } As you see I manually invoke begin and commit. Any ideas?

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  • How to make a custom ear file in maven

    - by Zombies
    Here is my challenge, I need to make an ear file for a specific container. To be more specific on how this ear will be created: This is a standard j2ee ear file, with 1 WAR in it. The container it is deployed to will expect certain xml files (which can easily be found (somewhere) inside the source project). Here are my obstacles The source folder contains various container specific xml files. But, these files do not map directly to where the container expects them inside the EAR file. For example, there will be a file that this container expects to be in 'EARFILE.ear/config/connections.xml'. But this file is located (in the source) at /some/obscure/unrelated/directory. This is the case for about 5-7 files. I cannot change the original source project layout at all. So, how can I create the compliant EAR file that I need. There is NO plugin at this time for the container that I am using, I have certainly looked.

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  • MySQL + Joomla + remote c# access

    - by Jimmy
    Hello, I work on a Joomla web site, installed on a MySQL database and running on IIS7. It's all working fine. I now need to add functionality that lets (Joomla-)registered users change some configuration data. Though I haven't done this yet, it looks straightforward enough to do with Joomla. The data is private so all external access will be done through HTTPS. I also need an existing c# program, running on another machine, to read that configuration data. Sure enough, this data access needs to be as fast as possible. The data will be small (and filtered by query), but the latency should be kept to a minimum. A short-term, client-side cache (less than a minute, in case a user updates his configuration data) seems like a good idea. I have done practically zero database/asp programming so far, so what's the best way of doing that last step? Should the c# program access the database 'directly' (using what? LINQ?) or setup some sort of Facade (SOAP?) service? If a service should be used, should it be done through Joomla or with ASP on IIS? Thanks

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  • Immutability and shared references - how to reconcile?

    - by davetron5000
    Consider this simplified application domain: Criminal Investigative database Person is anyone involved in an investigation Report is a bit of info that is part of an investigation A Report references a primary Person (the subject of an investigation) A Report has accomplices who are secondarily related (and could certainly be primary in other investigations or reports These classes have ids that are used to store them in a database, since their info can change over time (e.g. we might find new aliases for a person, or add persons of interest to a report) If these are stored in some sort of database and I wish to use immutable objects, there seems to be an issue regarding state and referencing. Supposing that I change some meta-data about a Person. Since my Person objects immutable, I might have some code like: class Person( val id:UUID, val aliases:List[String], val reports:List[Report]) { def addAlias(name:String) = new Person(id,name :: aliases,reports) } So that my Person with a new alias becomes a new object, also immutable. If a Report refers to that person, but the alias was changed elsewhere in the system, my Report now refers to the "old" person, i.e. the person without the new alias. Similarly, I might have: class Report(val id:UUID, val content:String) { /** Adding more info to our report */ def updateContent(newContent:String) = new Report(id,newContent) } Since these objects don't know who refers to them, it's not clear to me how to let all the "referrers" know that there is a new object available representing the most recent state. This could be done by having all objects "refresh" from a central data store and all operations that create new, updated, objects store to the central data store, but this feels like a cheesy reimplementation of the underlying language's referencing. i.e. it would be more clear to just make these "secondary storable objects" mutable. So, if I add an alias to a Person, all referrers see the new value without doing anything. How is this dealt with when we want to avoid mutability, or is this a case where immutability is not helpful?

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  • Why does the Maven goal "package" include the resources in the jar, but the goal "jar:jar" doesnt?

    - by Bernhard V
    Hi, when I package my project with the Maven goal "package", the resources are included as well. They are originally located in the directory "src/main/resources". Because I want to create an executable jar and add the classpath to the manifest, I'm using maven-jar-plugin. I've configured it as the following likes: <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-jar-plugin</artifactId> <version>2.2</version> <configuration> <archive> <manifest> <addClasspath>true</addClasspath> <mainClass>at.sozvers.stp.zpv.ekvkumsetzer.Main</mainClass> </manifest> </archive> </configuration> </plugin> Why won't the jar file created with "jar:jar" include my resources as well. As far as I'm concerned it should use the same directories as the "package" goal (which are in my case inherited from the Maven Super POM).

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  • How to "End Task" not "Kill" or "Terminate"?

    - by Luiscencio
    Hi community. I have a 3G card to provide internet to a remote computer... I have to run a program(provided with the card) to establish the connection... since connections suddenly is lost I wrote a script that Kills the program and reopens it so that the connection is reestablished, there are certain versions of this program that don't kill the connection when killed/terminated, just when closed properly. so I am looking for a script or program that "Properly Closes" a window so I can close it and reopen it in case the connection is lost. this is the code that kills the program Option Explicit Dim objWMIService, objProcess, colProcess Dim strComputer, strProcessKill strComputer = "." strProcessKill = "'Telcel3G.exe'" Set objWMIService = GetObject("winmgmts:" _ & "{impersonationLevel=impersonate}!\\" _ & strComputer & "\root\cimv2") Set colProcess = objWMIService.ExecQuery _ ("Select * from Win32_Process Where Name = " & strProcessKill ) For Each objProcess in colProcess objProcess.Terminate() Next WSCript.Echo "Just killed process " & strProcessKill _ & " on " & strComputer WScript.Quit

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  • Can the Visual Studio (2010) Command Window handle "external tools" with project/solution relative p

    - by ee
    I have been playing with the Command Window in Visual Studio (View-Other Windows-Command Window). It is great for several mouse-free scenarios. (The autocompleting file "Open" command rocks in a non-trivial solution.) That success got me thinking and experimenting: Possibility 1.1: You can use the Alias commands to create custom commands Possibility 1.2: You can use the Shell command to run arbitrary executables and specify parameters (and pipe the result to the output or command windows) Possibility 2: A previously setup external tool definition (with project-relative path variables) could be run from the command window What I am stuck on is: There doesn't appear to be a way to send parameters to an aliased command (and thus the underlying Shell call) There doesn't appear to be a way to use project/solution relative paths ($SolutionDir/$ProjectDir) on a Shell call Using absolute paths in Shell works, but is fragile and high-maintenance (one alias for each needed use case). Typically you want the command to run against a file relative to your project/solution. It seems you can't run the traditional external tools (Tools-External Tools...) in the command window Ultimately I want the external tool functionality in the command window in some way. Can anyone see a way to do this? Or am I barking up the wrong tree? So my questions: Can an "external tool" of some sort (using relative project/solution path parameters) be used in the Command Window? If yes, How? If no, what might be a suitable alternative?

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  • Cached data accessed by reference?

    - by arthurdent510
    I am running into an odd problem, and this is the only thing I can think of. I'm storing a list in cache, and I am randomly losing items from my list as users use the site. I have a class that is called that either goes to cache and returns the list from there, or if the cache is over a certain time frame old, it goes to the database and refreshes the cache. So when I pull the data from cache, this is what it looks like.... results = (List<Software>)cache["software"]; And then I return results and do some processing, filter for security, and eventually it winds up on the screen. For each Software record, there can be multiple resources attached to it, and based on how the security goes they may see some, all, or none of the records. So in the security check it will remove some of those resources from the software record. So my question is.... when I return my results list, is it a reference directly to the cache object? So when I remove a resource from the software object, it is really removing from cache as well? If that is the case, is there any way to not return it as a reference? Thanks!

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  • Interval arithmetic to correctly deal with end of month - Oracle SQL

    - by user2003974
    I need a function which will do interval arithmetic, dealing "correctly" with the different number of days in a month. For my version of "correctly" - see below! First try select to_date('31-May-2014') + interval '1' months from dual This returns an error, because there is no 31st June. I understand that this behaviour is expected due to the ANSI standard. Second try select add_months(to_date('31-May-2014'),1) from dual This correctly (in my use case) returns 30th June 2014, which is great. BUT select add_months(to_date('28-Feb-2014'),1) from dual returns 31st March 2014, when I want 28th March 2014. Background This has to do with legal deadlines. The deadlines are expressed in law as a number of months (say, 3) from a base date. If the base date is last day of the month and three months later the month is longer, then the deadline does NOT extend to the end of the longer month (as per the add_months function). However, if the base date is last day of the month and three months later the month is shorter, then the deadline expires on the last day of the shorter month. Question Is there a function that does what I need? I have intervals (year to month) stored in a table, so preferably the function would look like: add_interval_correctly(basedate DATE, intervaltoadd INTERVAL YEAR TO MONTH)

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  • trouble with state monad composition

    - by user1308560
    I was trying out the example given at http://www.haskell.org/haskellwiki/State_Monad#Complete_and_Concrete_Example_1 How this makes the solution composible is beyond my understanding. Here is what I tried but I get compile errors as follows: Couldn't match expected type `GameValue -> StateT GameState Data.Functor.Identity.Identity b0' with actual type `State GameState GameValue' In the second argument of `(>>=)', namely `g2' In the expression: g1 >>= g2 In an equation for `g3': g3 = g1 >>= g2 Failed, modules loaded: none. Here is the code: See the end lines module StateGame where import Control.Monad.State type GameValue = Int type GameState = (Bool, Int) -- suppose I want to play one game after the other g1 = playGame "abcaaacbbcabbab" g2 = playGame "abcaaacbbcabb" g3 = g1 >>= g2 m2 = print $ evalState g3 startState playGame :: String -> State GameState GameValue playGame [] = do (_, score) <- get return score playGame (x:xs) = do (on, score) <- get case x of 'a' | on -> put (on, score + 1) 'b' | on -> put (on, score - 1) 'c' -> put (not on, score) _ -> put (on, score) playGame xs startState = (False, 0) main str = print $ evalState (playGame str) startState

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  • Define "Validation in the Model"

    - by sunwukung
    There have been a couple of discussions regarding the location of user input validation: http://stackoverflow.com/questions/659950/should-validation-be-done-in-form-objects-or-the-model http://stackoverflow.com/questions/134388/where-do-you-do-your-validation-model-controller-or-view These discussions were quite old, so I wanted to ask the question again to see if anyone had any fresh input. If not, I apologise in advance. If you come from the Validation in the Model camp - does Model mean OOP representation of data (i.e. Active Record/Data Mapper) as "Entity" (to borrow the DDD terminology) - in which case you would, I assume, want all Model classes to inherit common validation constraints. Or can these rules simply be part of a Service in the Model - i.e. a Validation service? For example, could you consider Zend_Form and it's validation classes part of the Model? The concept of a Domain Model does not appear to be limited to Entities, and so validation may not necessarily need to be confined to this Entities. It seems that you would require a lot of potentially superfluous handing of values and responses back and forth between forms and "Entities" - and in some instances you may not persist the data recieved from user input, or recieve it from user input at all.

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