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  • When to use try/catch

    - by coffeeaddict
    I'm always finding myself wanting to put a try/catch around the lets say Business Layer methods. But I feel though that I don't need a try/catch if I'm simply rethrowing it up to the Presentation Layer. Is that right? I should not be rethrowing an exception from code that's wrapped in a try/catch in a BL method and should be letting the caller which would be from the Presentation Layer code be using a try/catch to handle it there? The BL method will throw an error without the try/catch anyway..the compiler will. So it wouldn't make sense to use a try/catch in a BL method that's to be consumed by a layer higher up correct?

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  • Writing text file on local server MVC 2.0

    - by Liado
    Hi, i'm trying to write a text file on remote server, i'm using the following code: [AcceptVerbs(HttpVerbs.Post)] public ActionResult Index(UserModels model) { if (!ModelState.IsValid) { return View("Index"); } try { using (StreamWriter w = new StreamWriter(Server.MapPath(TEXT_FILE_NAME), true)) { w.WriteLine(model.Email.ToString()); // Write the text } } catch { } the folder is still empty, can someone help? what should be the problem? Thanks

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  • Django: select_related and GenericRelation

    - by Parand
    Does select_related work for GenericRelation relations, or is there a reasonable alternative? At the moment Django's doing individual sql calls for each item in my queryset, and I'd like to avoid that using something like select_related. class Claim(models.Model): proof = generic.GenericRelation(Proof) class Proof(models.Model): content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField() content_object = generic.GenericForeignKey('content_type', 'object_id') I'm selecting a bunch of Claims, and I'd like the related Proofs to be pulled in instead of queried individually.

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  • Architectural Design for a Data-Driven Silverlight WP7 app

    - by Rosarch
    I have a Silverlight Windows Phone 7 app that pulls data from a public API. I find myself doing much of the same thing over and over again: In the UI, set a loading message or loading progress bar in place of where the content is Get the content, which may be already in memory, cached in isolated file storage, or require an HTTP request If the content can not be acquired (no network connection, etc), display an error message If the content is acquired, display it in the UI Keep the content in main memory for subsequent queries The content that is displayed to the user can be taken directly from a data source, such as an ObservableCollection, or it may be a query on a data source. I would like to factor out this repetitive process into a framework where ideally only the following needs to be specified: Where to display the content in the UI The UI elements to show while loading, on failure, and on success The URI of the HTTP request How to parse the HTTP response into the data structure that will kept in memory The location of the file in isolated storage, if it exists How to parse the file contents into the data structure that will be kept in memory It may sound like a lot, but two strings, three FrameworkElements, and two methods is less than the overhead that I currently have. Also, this needs to work for however the data is maintained in memory, and needs to work for direct collections and queries on those collections. My questions are: Has something like this already been implemented? Are my thoughts about the topic above fundamentally wrong in some way? Here is a design I'm thinking of: There are two components, a View and a Model. The View is given the FrameworkElements for loading, failure, and success. It is also given a reference to the corresponding Model. The View is a UserControl that is placed somewhere in the UI. The Model a class that is given the URI for the data, a method of how to parse the data, and optionally a filename and how to parse the file. It is responsible for retrieving the data and notifying the View whenever the current status (loading/fail/success) changes. If the data downloaded from the network is different from the cache, the network data takes precedence. When the app closes or is tombstoned, the model writes the data to the cache. How does that sound?

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  • Is it possible to bulk load an NDB child Entity in GAE?

    - by hmacread
    At some point in the future I may need to bulk load migration data (i.e. from a CSV). Has anyone had exceptions raised doing the following? Also is there any change in behaviour if the ndb.put_multi() function is used? from google.appengine.ext import ndb while True: if not id: break id, name = read_csv_row(readline()) x = X(parent=ndb.Key('Y','static_id') x.id, x.name = id, name x.put() class X(ndb.Model): id = StringProperty() name = StringProperty() class Y(ndb.Model): pass def read_csv_row(line): """returns tuple"""

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  • Connection between Properties of Entities in Data Oriented Design

    - by sharethis
    I want to start with an example illustrating my question. The following way it is done in the most games. class car { vec3 position; vec3 rotation; mesh model; imge texture; void move(); // modify position and rotation void draw(); // use model, texture, ... }; vector<car> cars; for(auto i = cars.begin(); i != cars.end(); ++i) { i->move(); i->draw(); } Data oriented design means to process the same calculation on the hole batch of data at once. This way it takes more advantage out of the processor cache. struct movedata { vec3 position; vec3 rotation; }; struct drawdata { mesh model; imge texture; }; vector<movedata> movedatas; vector<drawdata> drawdatas; for(auto i = movedatas.begin(); i != movedatas.end(); ++i) { // modify position and rotation } for(auto i = drawdatas.begin(); i != drawdatas.end(); ++i) { // use model, texture, ... } But there comes a point where you need to find other properties according to an entity. For example if the car crashes, I do not need the drawdata and the movedata any more. So I need to delete the entries of this entity in all vectors. The entries are not linked by code. So my question is the following. How are properties of the same entity conceptually linked in a data oriented design?

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  • No more memory available in Mathematica, Fit the parameters of system of differential equation

    - by user1058051
    I encountered a memory problem in Mathematica, when I tried to process my experimental data. It's a system of two differential equations and I need to find most suitable parameters. Unfortunately I am not a Pro in Mathematica, so the program used a lot of memory, when the parameter epsilon is more than 0.4. When it less than 0.4, the program work properly. The command 'historylength = 0' and attempts to reduce the Accuracy Goal and WorkingPrecision didn`t help. I can't use ' clear Cache ', because there isnt a circle. I'm trying to understand what mistakes I made, and how I may limit the memory usage. I have already bought extra-RAM, now its 4GB, and now I haven't free memory-slots in motherboard Remove["Global`*"]; T=13200; L = 0.085; e = 0.41; v = 0.000557197; q = 0.1618; C0 = 0.0256; R = 0.00075; data = {{L,600,0.141124587},{L,1200,0.254134509},{L,1800,0.342888644}, {L,2400,0.424476295},{L,3600,0.562844542},{L,4800,0.657111356}, {L,6000,0.75137817},{L,7200,0.815876516},{L,8430,0.879823594}, {L,9000,0.900771775},{L,13200,1}}; model[(De_)?NumberQ, (Kf_)?NumberQ, (Y_)?NumberQ] := model[De, Kf, Y] = yeld /.Last[Last[ NDSolve[{ v (Ci^(1,0))[z,t]+(Ci^(0,1))[z,t]== -((3 (1-e) Kf (Ci[z,t]-C0))/ (R e (1-(R Kf (1-R/r[z,t]))/De))), (r^(0,1))[z,t]== (R^2 Kf (Ci[z,t]-C0))/ (q r[z,t]^2 (1-(R Kf (1-R/r[z,t]))/De)), (yeld^(0,1))[z,t]== Y*(v e Ci[z,t])/(L q (1-e)), r[z,0]==R, Ci[z,0]==0, Ci[0,t]==0, yeld[z,0]==0}, {r[z,t],Ci[z,t],yeld},{z,0,L},{t,0,T}]]] fit = FindFit[data, {model[De, Kf, Y][z, t], {Y > 0.97, Y < 1.03, Kf > 10^-6, Kf < 10^-4, De > 10^-13, De < 10^-9}}, {{De,7*10^-13}, {Kf, 10^-5}, {Y, 1}}, {z, t}, Method -> NMinimize] data = {{600,0.141124587},{1200,0.254134509},{1800,0.342888644}, {2400,0.424476295},{3600,0.562844542},{4800,0.657111356}, {6000,0.75137817},{7200,0.815876516},{8430,0.879823594}, {9000,0.900771775},{13200,1}}; YYY = model[ De /. fit[[1]], Kf /. fit[[2]], Y /. fit[[3]]]; Show[Plot[Evaluate[YYY[L,t]],{t,0,T},PlotRange->All], ListPlot[data,PlotStyle->Directive[PointSize[Medium],Red]]] the link on the .nb file http://www.4shared.com/folder/249TSjlz/_online.html

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  • Problem persisting inheritance tree

    - by alaiseca
    I have a problem trying to map an inheritance tree. A simplified version of my model is like this: @MappedSuperclass @Embeddable public class BaseEmbedded implements Serializable { @Column(name="BE_FIELD") private String beField; // Getters and setters follow } @MappedSuperclass @Embeddable public class DerivedEmbedded extends BaseEmbedded { @Column(name="DE_FIELD") private String deField; // Getters and setters follow } @MappedSuperclass public abstract class BaseClass implements Serializable { @Embedded protected BaseEmbedded embedded; public BaseClass() { this.embedded = new BaseEmbedded(); } // Getters and setters follow } @Entity @Table(name="MYTABLE") @Inheritance(strategy=InheritanceType.SINGLE_TABLE) @DiscriminatorColumn(name="TYPE", discriminatorType=DiscriminatorType.STRING) public class DerivedClass extends BaseClass { @Id @Column(name="ID", nullable=false) private Long id; @Column(name="TYPE", nullable=false, insertable=false, updatable=false) private String type; public DerivedClass() { this.embedded = new DerivedClass(); } // Getters and setters follow } @Entity @DiscriminatorValue("A") public class DerivedClassA extends DerivedClass { @Embeddable public static NestedClassA extends DerivedEmbedded { @Column(name="FIELD_CLASS_A") private String fieldClassA; } public DerivedClassA() { this.embedded = new NestedClassA(); } // Getters and setters follow } @Entity @DiscriminatorValue("B") public class DerivedClassB extends DerivedClass { @Embeddable public static NestedClassB extends DerivedEmbedded { @Column(name="FIELD_CLASS_B") private String fieldClassB; } public DerivedClassB() { this.embedded = new NestedClassB(); } // Getters and setters follow } At Java level, this model is working fine, and I believe is the appropriate one. My problem comes up when it's time to persist an object. At runtime, I can create an object which could be an instance of DerivedClass, DerivedClassA or DerivedClassB. As you can see, each one of the derived classes introduces a new field which only makes sense for that specific derived class. All the classes share the same physical table in the database. If I persist an object of type DerivedClass, I expect fields BE_FIELD, DE_FIELD, ID and TYPE to be persisted with their values and the remaining fields to be null. If I persist an object of type DerivedClass A, I expect those same fields plus the FIELD_CLASS_A field to be persisted with their values and field FIELD_CLASS_B to be null. Something equivalent for an object of type DerivedClassB. Since the @Embedded annotation is at the BaseClass only, Hibernate is only persisting the fields up to that level in the tree. I don't know how to tell Hibernate that I want to persist up to the appropriate level in the tree, depending on the actual type of the embedded property. I cannot have another @Embedded property in the subclasses since this would duplicate data that is already present in the superclass and would also break the Java model. I cannot declare the embedded property to be of a more specific type either, since it's only at runtime when the actual object is created and I don't have a single branch in the hierarchy. Is it possible to solve my problem? Or should I resignate myself to accept that there is no way to persist the Java model as it is? Any help will be greatly appreciated.

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  • Setting custom SQL in django admin

    - by eugene y
    I'm trying to set up a proxy model in django admin. It will represent a subset of the original model. The code from models.py: class MyManager(models.Manager): def get_query_set(self): return super(MyManager, self).get_query_set().filter(some_column='value') class MyModel(OrigModel): objects = MyManager() class Meta: proxy = True Now instead of filter() I need to use a complex SELECT statement with JOINS. What's the proper way to inject it wholly to the custom manager?

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  • Asp.Net MVC How to test that the view rendered

    - by Miau
    HI there I was wondering if there is a better way of testing that a view has rendered in MVC. I was thinking perhaps I should render the view to a string but perhaps there are simpler methods? Basically what I want to know if that the view for a given action has rendered without errors I m already testing the view model but I want to see that rendering the view giving a correct ViewData.Model works

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  • How to save link with tag e parameters in TextField

    - by xRobot
    I have this simple Post model: class Post(models.Model): title = models.CharField(_('title'), max_length=60, blank=True, null=True) body = models.TextField(_('body')) blog = models.ForeignKey(Blog, related_name="posts") user = models.ForeignKey(User) I want that when I insert in the form the links, the these links are saved in the body from this form: http://www.example.com or www.example.com to this form ( with tag and rel="nofollow" parameter ): <a href="http://www.example.com" rel="nofollow">www.example.com</a> How can I do this ? Thanks ^_^

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  • Lithium: Run filter after find() to format output

    - by Housni
    I wanted to specify the output of a field from within my model so I added a date key to my $_schema: models/Tags.php <?php protected $_schema = array( 'id' => array('type' => 'integer', 'key' => 'primary'), 'title' => array('type' => 'string'), 'created' => array('type' => 'integer', 'date' => 'F jS, Y - g:i a'), 'modified' => array('type' => 'integer') ); ?> I store my time as an unsigned integer in the db (output of time()). I want my base model to format any field that has the date key for output. I thought the best place to do that would be right after a find: extensions/data/Model.php <?php static::applyFilter('find', function($self, $params, $chain) { $schema = $self::schema(); $entity = $chain->next($self, $params, $chain); foreach ($schema as $field => $options) { if (array_key_exists('date', $options)) { //format as a date $params['data'][$field] = $entity->formatDate($field, $options['date']); } } return $entity; }); public function formatdate($entity, $field, $format, $timezone = 'Asia/Colombo') { $dt = new \DateTime(); $tz = new \DateTimeZone($timezone); $dt->setTimestamp($entity->$field); $dt->setTimezone($tz); return $dt->format($format); } ?> This doesn't seem to be working. When I execute a find all, this filter seems to get hit twice. The first time, $entity contains a count() of the results and only on the second hit does it contain the Records object. What am I doing wrong? How do I alter this so that simply doing <?= $tag->created; ?> in my view will format the date the way I want? This, essentially, needs to be an 'after filter', of sorts. EDIT If I can find a way to access the current model entity object (not the full namespaced path, $self contains that), I can probably solve my problem.

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  • View / ViewModel - what is the sense (in a WPF control)?

    - by TomTom
    Not as funny as it sounds. Normally the View / ViewModel should decouple the presentation from the business logic. Good. Now, a Control in WPF is basically invisible unless made different (with the exceptions of UserControl and Window that have XAML directly attached). The Style is putting in the "visual presentation" - which basically means a Control does not need a view mechanism as WPF already has one? In addition. the ViewModel is actually part of the Control, or? Just fighting with that stuff. I know in ASP.NET, WinForms the separation makes a lot of sense - but there, basically, controls HAVE an intrinsic look. In WPF, I have some where it makes sense (derived from UserControl), but for the majority of the controls I write, the View & ViewModel look like pretty much totally superflous thanks to the already presenting view mechanism.

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  • Entity Framework equivalence for NHibernte SchemaExport

    - by jbandi
    Is there an equivalence in Entity Framework to NHibernate SchemaExport? Given I have a working Entity-Model, I would like to programmatically initialize a database. I would like to use this functionality in the setup of my integration tests. Creating the matching DDL for an Entity-Model would also suffice.

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  • What can be inside a class that derive from OmniAuth?

    - by Richard77
    I have the following class class Identity < OmniAuth:: Identity:: Models:: ActiveRecord attr_accessible :email, :name, :password_digest, :password, :password_confirmation end I wonder if the above properties are the only ones allowed for a class that derive from a OmniAuth. I wish I could add some more like FirstName, LastName, age, gender, and so on. Do I need to create an other model for those properties or can I just add them to the Identity model? Thanks for helping.

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  • Shuffling a list with a constraint

    - by 500
    Preparing a new psychophysic experiment, I have 48 original stimuli displayed 4 times (4 conditions). Resulting in 192 trials. Trying to randomize the order of presentation during the experiment, I need to maximize the distance between the 4 display of the same original stimuli. Please Consider : Table[{j, i}, {j, Range[48]}, {i, Range[4]}] Where j is the original stimuli number and i the condition Output Sample : {{1, 1}, {1, 2}, {1, 3}, {1, 4}, {2, 1}, {2, 2}, {2, 3}, {2, 4}, ... {47, 1}, {47, 2}, {47, 3},{47, 4}, {48, 1}, {48, 2}, {48, 3}, {48, 4}} How could I shuffle the order of presentation of those 192 items, maximizing the distance between identical item with regard to j the original stimuli number ?

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  • Object Oriented vs Relational Databases

    - by Dan
    Objects oriented databases seem like a really cool idea to me, no need to worry about mapping your domain model to your database model, no messing around with sql or ORM tools. The way I understand it, relational DBs offer some advantages when there is massive amounts of data, and searching an indexing need to be done. To my mind 99% of websites are not massive, and enterprise issues never need to be thought about, so why arn't OO DBs more widely used?

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  • What's the correct way to instantiate an IRepository class from the Controller?

    - by GenericTypeTea
    I have the following project layout: MVC UI |...CustomerController (ICustomerRepository - how do I instantiate this?) Data Model |...ICustomerRepository DAL (Separate Data access layer, references Data Model to get the IxRepositories) |...CustomerRepository (inherits ICustomerRepository) What's the correct way to say ICustomerRepository repository = new CustomerRepository(); when the Controller has no visibility to the DAL project? Or am I doing this completely wrong?

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  • Django menu item sorting

    - by doktorno
    Hi i've got MenuItem model : MenuItem(models.Model) name=models.CharField(max_length=50) url = models.URLField() position = models.IntegerField() Class Meta: ordering =['position'] then i'm retriving it by MenuItem.objects.all() My question is how can i make any user friendly interface in admin panel to allow sorting MenuItems - for example list with + and - buttons to move MenuItem up and down ....

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  • Default FileField names for Django files

    - by Adam Nelson
    I have a model: class Example(models.Model): unique_hash = models.CharField(max_length=32,unique=True) content = models.FileField(upload_to='source',blank=True,verbose_name="HTML Content File") I would like to be able to set the content filename to default to a callable, but I don't see any way to have the callable reference unique_hash (or vice versa). Is this possible?

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  • Can an ActiveRecord before_save filter halt the save without halting the transaction?

    - by Michael Boutros
    Is there any way for a before_save filter to halt the entire save without halting the transaction? What I'm trying to do is have a "sample" version of my model that the user can interact with and save but the changes themselves are never actually saved. The following will halt the transaction and (naturally) return false when I call @model.update_attributes: before_filter :ignore_changes_if_sample def ignore_changes_if_sample if self.sample? return false end end Thanks!

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  • rake does not returning anything

    - by CHID
    Hi, I jus created a rails application. I created a model using ruby script/generate model Article next i edited the my articles.rb file by adding these lines in self.up method def self.up create_table :articles do |t| t.string :title t.text :body t.string :published_at t.timestamps end end Now i ran rake db:migrate . But migrate does not work, it simply does no print anything. Anyone knows where i am going wrong?

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  • How to access image folder in django

    - by anc1revv
    I just started django and i want to access images uploaded by a user. here is my model: class Food(models.Model): name = models.CharField(max_length=100) price = models.DecimalField(max_digits=4, decimal_places=2) quantity = models.IntegerField(blank=True, null=True) description = models.CharField(max_length=200) location = models.CharField(max_length=100) time = models.DateTimeField() photo_thumbnail = models.ImageField(upload_to="images") photo_fullsize = models.ImageField(upload_to="images") i stored the image in the "images" folder below the html is this: img src="{{steak.photo_thumbnail}}" and steak.photo_thumbnail = images/steak_and_egg_thumbnail_1.png here is the error i get: [06/Jul/2012 19:08:24] "GET /menu/ HTTP/1.1" 200 99 [06/Jul/2012 19:08:24] "GET /menu/images/steak_and_egg_thumbnail_1.png HTTP/1.1" 404 2127

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