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  • Help with complex MVVM (multiple views)

    - by jsjslim
    I need help creating view models for the following scenario: Deep, hierarchical data Multiple views for the same set of data Each view is a single, dynamically-changing view, based on the active selection Depending on the value of a property, display different types of tabs in a tab control My questions: Should I create a view-model representation for each view (VM1, VM2, etc)? 1. Yes: a. Should I model the entire hierarchical relationship? (ie, SubVM1, HouseVM1, RoomVM1) b. How do I keep all hierarchies in sync? (e.g, adding/removing nodes) 2. No: a. Do I use a huge, single view model that caters for all views? Here's an example of a single view Figure 1: Multiple views updated based on active room. Notice Tab control Figure 2: Different active room. Multiple views updated. Tab control items changed based on object's property. Figure 3: Different selection type. Entire view changes

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  • DopeWarz 2010

    - by Theo Moore
    A few (6?) weeks ago, I started a project that I've always wanted to do. I am doing a re-write of the old VB6 game DopeWars with a partner in crime. I loved that game and spent many, many hours wasting time playing it years ago. I liked it so much, I even registered it (it was $5...even then, that wasn't much to spend). The VB6 version itself was a port of the old DOS game DrugWars (never go to play that). I needed a game project to work on as it's been far too long since I've done any game work. There is surprising amount of logic built into the game (there is the way I'm writing it, anyway) with what is really a minimal interface. My design goal was to have an object model that could be easily adapted to any interface and so far, I've managed to do that. I am even considering a web-based version that could run via Facebook (no clue how to do that...yet). I've enlisted the help of one of my DBA buddies to work on the interface while I am working on the object model. So far, this arrangement has gone well. The logical separation of concerns allows for us to collaborate easily. Once we get to the Facebook step, it will be great to have a DBA "on staff" to help that part off of the ground. The object model is probably about 60% complete with quite a bit of testing to go. More on this as we go....

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  • Server side C# MVC with AngularJS

    - by Ryan Langton
    I like using .NET MVC and have used it quite a bit in the past. I have also built SPA's using AngularJS with no page loads other than the initial one. I think I want to use a blend of the two in many cases. Set up the application initially using .NET MVC and set up routing server side. Then set up each page as a mini-SPA. These pages can be quite complex with a lot of client side functionality. My confusion comes in how to handle the model-view binding using both .NET MVC and the AngularJS scope. Do I avoid the use of razor Html helpers? The Html helpers create the markup behind the scene so it could get messy trying to add angularjs tags using the helpers. So how to add ng-model for example to @Html.TextBoxFor(x = x.Name). Also ng-repeat wouldn't work because I'm not loading my model into the scope, right? I'd still want to use a c# foreach loop? Where do I draw the lines of separation? Has anyone gotten .NET MVC and AngularJS to play nicely together and what are your architectural suggestions to do so?

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  • Should we be able to deploy a single package to the SSIS Catalog?

    - by jamiet
    My buddy Sutha Thiru sent me an email recently asking about my opinion on a particular nuance of the project deployment model in SQL Server Integration Services (SSIS) 2012 and I’d like to share my response as I think it warrants a wider discussion. Sutha asked: Jamie What is your take on this? http://www.mattmasson.com/index.php/2012/07/can-i-deploy-a-single-ssis-package-from-my-project-to-the-ssis-catalog/ Overnight I was talking to Matt who confirmed that they got no plans to change the deployment model. For example if we have following scenrio how do we do deploy? Sprint 1 Pkg1, 2 & 3 has been developed and deployed to UAT. Once signed off its been deployed to Live. Sprint 2 Pkg 4 & 5 been developed. During this time users raised a bug on Pkg2. We want to make the change to Pkg2 and deploy that to UAT and eventually to LIVE without releasing Pkg 4 &5. How do we do it? Matt pointed me to his blog entry which I have seen before . http://www.mattmasson.com/index.php/2012/02/thoughts-on-branching-strategies-for-ssis-projects/ Thanks Sutha My response: Personally, even though I've experienced the exact problem you just outlined, I agree with the current approach. I steadfastly believe that there should not be a way for an unscrupulous developer to slide in a new version of a package under the covers. Deploying .ispac files brings a degree of rigour to your operational processes. Yes, that means that we as SSIS developers are going to have to get better at using source control and branching properly but that is no bad thing in my opinion. Claiming to be proper "developers" is a bit of a cheap claim if we don't even do the fundamentals correctly. I would be interested in the thoughts of others who have used the project deployment model. Do you agree with my point of view? @Jamiet

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  • ArchBeat Link-o-Rama for October 29, 2013

    - by OTN ArchBeat
    Exceptions Handling and Notifications in ODI | Christophe Dupupet Oracle Fusion Middleware A-Team director Christophe Dupupet reviews the techniques that are available in Oracle Data Integrator to guarantee that the appropriate individuals are notified in the event that ODI processes are impacted by network outages or other mishaps. Tech Article: SOA in Real Life: Mobile Solutions The latest article in the Industrial SOA series looks at mobile computing and how companies are developing SOA to go. Oracle Coherence, Split-Brain and Recovery Protocols In Detail | Ricardo Ferreira Ricardo Ferreira's article "provides a high level conceptual overview of Split-Brain scenarios in distributed systems," focusins on a "specific example of cluster communication failure and recovery in Oracle Coherence." WebLogic & FMW Provisioning update | Edwin Biemond "Provisioning was a hot topic on Oracle Openworld 2013," says Oracle ACE Edwin Biemond. His latest blog post discusses what is now possible with WebLogic and Fusion Middleware, and looks at what might be possible in the future. Reusing and Extending ADF BC Entities from Common Model | Andrejus Baranovskis Oracle ACE Director Andrejus Baranovskis' post is about "ADF architecture and better application structuring with EO reuse from a common model." Andrejus describes "how to implement additional requirements to common model in extended ADF BC Entities." Thought for the Day "I work hard, I work late, I have nothing on my conscience. When I go to bed, I sleep." — Ellen Johnson Sirleaf, 24th and current President of Liberia (Born 29 October 1938) Source: brainyquote.com

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  • 3ds Max error dialog: "Instancing not supported for this action"

    - by monsto
    "Instancing not supported for this action” is the dialog I get. My favorite part is that, according to google and yahoo, apparently i am the only person in the history of mankind to experience these words together in this order, let along get this message from Max. Thanks, autodesk, for putting this dialog in special for me! So I’ve created my model (nws) and was setting up a Skin Wrap. Selected "Face Deformation", added the base-skin for weight, checked “weight all points”. . . clicked “convert to skin” and got that dialog. My model doesn’t have a whole lot of elements to it, I had a left and right appendage that came from a base model (skyrim). so, i did a clonecopy of all 3 of my elements, just to be sure nothing was instanced… and VOILA! Same error message. the only other elements are an imported NIF mesh and skeleton. Any idea where this is coming from or how I can make it go away so that I can export my mesh?

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  • A good substitute for ASMX web service methods, but not a general handler

    - by Saeed Neamati
    The best thing I like about ASP.NET MVC, is that you can directly call a server method (called action), from the client. This is so convenient, and so straightforward, that I really like to implement such a model in ASP.NET WebForms too. However, in ASP.NET WebForms, to call a server method from the client, you should either use Page Methods, or Web Services, both of which use SOAP as their communication protocol (though JSON can also be used). There is also another substitution, which is using Generic Handlers. The problem with them however is that, a separate Generic Handler should be written for each server method. In other words, each Generic Handler works like a simple method. Is there anyway else to imitate MVC model in ASP.NET WebForms? Please note that I can't change to MVC platform right now, cause the project at our hand is a big project and we don't have required resources and time to change our platform. What we seek, is a simple MVC model implementation for our AJAX calls. A problem that we have with Web Services, is the known problem of SoapException, and we're not interested in creating custom SoapExctensions.

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  • SQLAuthority News – Download Whitepaper – Choosing a Tabular or Multidimensional Modeling Experience in SQL Server 2012 Analysis Services

    - by pinaldave
    Data modeling is the most important task for any BI professional. Matter of the fact, the biggest challenge is to organizing disparate data into an analytic model that effectively and efficiently supports the reporting and analysis. SQL Server 2012 introduces BI Semantic Model (BISM), a single model that can support a broad range of reporting and analysis while blending two Analysis Services modeling experiences behind the scenes. Multidimensional modeling – enables BI professionals to create sophisticated multidimensional cubes using traditional online analytical processing (OLAP). Tabular modeling – provides self-service data modeling capabilities to business and data analysts. As data modeling is evolving and business needs are growing new technologies and tools are emerging to help end users to make the necessary adjustment to the reporting and analysis needs. This white paper is will provide practical guidance to help you decide which SQL Server 2012 Analysis Services modeling experience – tabular or multidimensional. Do let me know what do is your opinion as a comment. In simple word – I would like to know when will you use Tabular modeling and when Multidimensional modeling? Download Choosing a Tabular or Multidimensional Modeling Experience in SQL Server 2012 Analysis Services Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Business Intelligence, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL White Papers, T SQL, Technology

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  • Workaround: build FBX in XNA raise OutOfMemoryException

    - by Vitus
    If you try to add large FBX 3D model to the XNA project, and build it, you can get an OutOfMemoryException build error like following: Error    1    Building content threw OutOfMemoryException: Exception of type 'System.OutOfMemoryException' was thrown.    at System.Collections.Generic.List`1.set_Capacity(Int32 value)    at System.Collections.Generic.List`1.EnsureCapacity(Int32 min)    at System.Collections.Generic.List`1.InsertRange(Int32 index, IEnumerable`1 collection)    at Microsoft.Xna.Framework.Content.Pipeline.Graphics.VertexChannel`1.InsertRange(Int32 index, Int32 count)    at Microsoft.Xna.Framework.Content.Pipeline.Graphics.VertexContent.InsertRange(Int32 index, IEnumerable`1 positionIndexCollection)    at Microsoft.Xna.Framework.Content.Pipeline.Graphics.MeshBuilder.AddTriangleVertex(Int32 indexIntoVertexCollection)    at Microsoft.Xna.Framework.Content.Pipeline.MeshConverter.FillNodeWithInfoFromMesh(KFbxNode* fbxNode, String name, KFbxGeometryConverter* geometryConverter)    at Microsoft.Xna.Framework.Content.Pipeline.FbxImporter.ProcessInformationInNode(KFbxNode* fbxNode, String name, Boolean* partOfMainSkeleton, Boolean* warnIfBoneButNotChild)    at Microsoft.Xna.Framework.Content.Pipeline.FbxImporter.ProcessNode(ValueType parentAbsoluteTransform, NodeContent potentialParent, KFbxNode* fbxNode, Boolean partOfMainSkeleton, Boolean warnIfBoneButNotChild)    at Microsoft.Xna.Framework.Content.Pipeline.FbxImporter.ProcessNode(ValueType parentAbsoluteTransform, NodeContent potentialParent, KFbxNode* fbxNode, Boolean partOfMainSkeleton, Boolean warnIfBoneButNotChild)    at Microsoft.Xna.Framework.Content.Pipeline.FbxImporter.Import(String filename, ContentImporterContext context)    at Microsoft.Xna.Framework.Content.Pipeline.ContentImporter`1.Microsoft.Xna.Framework.Content.Pipeline.IContentImporter.Import(String filename, ContentImporterContext context)    //additional calls here …   My desktop PC have 8Gb RAM, and Visual Studio’s process devenv.exe use under 2Gb of it while build process (about 3.5-4Gb of RAM is always free). It’s obvious, that VS can’t address more than 2Gb of RAM, and when that limit is over, build process is fail. OS on my PC is Win x64,  so I “charge” devenv.exe by using editbin.exe utility – in the VS Command prompt I run following: editbin "C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\devenv.exe" /LARGEADDRESSAWARE This command edits the image to indicate that the application can handle addresses larger than 2 gigabytes. After that FBX file successfully built! Of course, you must put proper path to devenv.exe, depend on your installation path. If you are on Win x86, you need to do additional action – more info here.   P.S.: although now you can build a bigger files, than usual, keep in mind, that XNA have some restrictions on vertex buffer size etc., depend on your current XNA project profile (Reach or HiDef). And if your model’s vertexbuffer size more than 64Mb (with Reach profile), that model can’t be built and raise an error.

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  • Distinction between API and frontend-backend

    - by Jason
    I'm trying to write a "standard" business web site. By "standard", I mean this site runs the usual HTML5, CSS and Javascript for the front-end, a back-end (to process stuff), and runs MySQL for the database. It's a basic CRUD site: the front-end just makes pretty whatever the database has in store; the backend writes to the database whatever the user enters and does some processing. Just like most sites out there. In creating my Github repositories to begin coding, I've realized I don't understand the distinction between the front-end back-end, and the API. Another way of phrasing my question is: where does the API come into this picture? I'm going to list some more details and then questions I have - hopefully this gives you guys a better idea of what my actual question is, because I'm so confused that I don't know the specific question to ask. Some more details: I'd like to try the Model-View-Controller pattern. I don't know if this changes the question/answer. The API will be RESTful I'd like my back-end to use my own API instead of allowing the back-end to cheat and call special queries. I think this style is more consistent. My questions: Does the front-end call the back-end which calls the API? Or does the front-end just call the API instead of calling the back-end? Does the back-end just execute an API and the API returns control to the back-end (where the back-end acts as the ultimate controller, delegating tasks)? Long and detailed answers explaining the role of the API alongside the front-end back-end are encouraged. If the answer depends on the model of programming (models other than the Model-View-Controller pattern), please describe these other ways of thinking of the API. Thanks. I'm very confused.

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  • Segmentation fault while switching QCompleter for QLineEdit [on hold]

    - by san
    I have a QLineEdit that uses autocompletion one which on focusIn event in which it shows paths from XML List(here I have used hardcoded list) but if user doesn't find the path from that list popped by QCompleter than I want user to be able to browse to path typing '/' in QLineEdit , I am not able to select the paths say /Users etc and on trying to type Segmentation fault occurs. from PyQt4.Qt import Qt, QObject,QLineEdit from PyQt4.QtCore import pyqtSlot,SIGNAL,SLOT from PyQt4 import QtGui, QtCore import sys class DirLineEdit(QLineEdit, QtCore.QObject): """docstring for DirLineEdit""" def __init__(self): super(DirLineEdit, self).__init__() self.defaultList = ['~/Development/python/searchMethod', '~/Development/Nuke_python', '~/Development/python/openexr', '~/Development/python/cpp2python'] self.textChanged.connect(self.__dirCompleter) def focusInEvent(self, event): if len(self.text()) == 0: self._pathsList() QtGui.QLineEdit.focusInEvent(self, event) self.completer().complete() def __dirCompleter(self): if len(self.text()) == 0: model = MyListModel(self.defaultList, self) completer = QtGui.QCompleter(model, self) completer.setModel(model) else: dirModel = QtGui.QFileSystemModel() dirModel.setRootPath(QtCore.QDir.currentPath()) dirModel.setFilter(QtCore.QDir.AllDirs | QtCore.QDir.NoDotAndDotDot | QtCore.QDir.Files) dirModel.setNameFilterDisables(0) completer = QtGui.QCompleter(dirModel, self) completer.setCaseSensitivity(QtCore.Qt.CaseInsensitive) completer.setModel(dirModel) self.setCompleter(completer) def _pathsList(self): completerList = QtCore.QStringList() for i in self.defaultList: completerList.append(QtCore.QString(i)) lineEditCompleter = QtGui.QCompleter(completerList) lineEditCompleter.setCompletionMode(QtGui.QCompleter.UnfilteredPopupCompletion) self.setCompleter(lineEditCompleter) class MyListModel(QtCore.QAbstractListModel): def __init__(self, datain, parent=None, *args): """ datain: a list where each item is a row """ QtCore.QAbstractTableModel.__init__(self, parent, *args) self.listdata = datain def rowCount(self, parent=QtCore.QModelIndex()): return len(self.listdata) def data(self, index, role): if index.isValid() and role == QtCore.Qt.DisplayRole: return QtCore.QVariant(self.listdata[index.row()]) else: return QtCore.QVariant() app = QtGui.QApplication(sys.argv) smObj = DirLineEdit() smObj.show() app.exec_() Please help fix this or suggest better way of implementation?

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  • What the Hekaton?

    - by Tony Davis
    Hekaton, the power behind SQL Server 2014′s In-Memory OLTP technology, is intended to make data operations run orders of magnitude faster on SQL Server. This works its magic partly by serving database workloads entirely from main memory, using memory-optimized table structures. It replaces the relational engine’s standard locking model with an optimistic concurrency model based on time-stamped row versions. Deeper down the Hekaton engine uses new, ‘latch free’ data structures. So far, so good, but performance improvements on this scale require a compromise, and the compromise is that these aren’t tables as we understand them. For the database developer, these differences are painful because they involve sacrificing some very important bits of the relational model. Most importantly, Hekaton tables don’t currently support FOREIGN KEY constraints or CHECK constraints, and you can’t put the checks in triggers because there aren’t any DML triggers either. Constraints allow a relational designer to enforce relational integrity and data integrity. Without them, of course, ‘bad data’ can get into our Hekaton tables. There is no easy way of preventing it. For several classes of database and data, this is a show-stopper. One may regard all these restrictions regretfully, seeing limited opportunity to try out Hekaton with current databases, but perhaps there is also a sudden glow of recognition. Isn’t this how we all originally imagined table variables were going to be, back in SQL 2005? And they have much the same restrictions. Maybe, instead of pretending that a currently-designed database can be ‘Hekatonized’ with a few mouse clicks, we should redesign databases for SQL 2014 to replace table variables with Hekaton tables, exploiting this technology for fast intermediate processing, and for the most part forget, for now, the idea of trying to convert our base relational tables into Hekaton tables. Few database developers would be averse to having their working tables running an order of magnitude faster, as long as it didn’t compromise the integrity of the data in the base tables.

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  • How to parse JSON data from web more faster [closed]

    - by Kaidul Islam Sazal
    I have json inventory inventory.json on the server like this: [ { "body" : "SUV", "color" : { "ext" : "White diamond pearl", "int" : "Taupe" }, "id" : "276181", "make" : "Acura", "miles" : 35949, "model" : "RDX", "pic" : [ { "full" : "http://images1.dealercp.com/90961/000JNBD/001_0292.jpg" } ], "power" : { "drive" : "Front wheel drive", "eng" : "2.3L DOHC PGM-FI 16-VALVE", "trans" : "Automatic" }, "price" : { "net" : 29488 }, "stock" : "6942", "trim" : "AWD 4dr Tech Pkg SUV", "vin" : "5J8TB2H53BA000334", "year" : 2011 }, { "body" : "Sedan", "color" : { "ext" : "Premium white pearl", "int" : "Taupe" }, "id" : "275622", "make" : "Acura", "miles" : 40923, "model" : "TSX", "pic" : [ { "full" : "http://images1.dealercp.com/90961/000JMC6/001_1765.jpg" } ], "power" : { "drive" : "Front wheel drive", "eng" : "2.4L L4 MPI DOHC 16V", "trans" : "Automatic" }, "price" : { "net" : 22288 }, "stock" : "6945", "trim" : "4dr Sdn I4 Auto Sedan", "vin" : "JH4CU2F66AC011933", "year" : 2010 } ] here are two index, There are almost 5000 index like this. I parsed this json like this: var url = "inventory/inventory.json"; $.getJSON(url, function(data){ $.each(data, function(index, item){ //straight-forward loop if(item.year == 2012) { $('#desc').append(item.make + ' ' + item.model + ' ' + '<br/>' + item.price.net + '<br/>' + item.pic[0].full); } }); }); This is working fine.But the problem is that, this searching and fetching process is little bit slow as there are 5000 indexes already and it's increasing day by day. It seems that, it is a straight-forward loop to parse the data and a normal brute-force method. Now I want to know if there any time efiicient way to parse more faster.Any faster method to parse instead of straight-forward loop ?

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  • Modelling work-flow plus interaction with a database - quick and accessible options

    - by cjmUK
    I'm wanting to model a (proposed) manufacturing line, with specific emphasis on interaction with a traceability database. That is, various process engineers have already mapped the manufacturing process - I'm only interested in the various stations along the line that have to talk to the DB. The intended audience is a mixture of project managers, engineers and IT people - the purpose is to identify: points at which the line interacts with the DB (perhaps going so far as indicating the Store Procs called at each point, perhaps even which parameters are passed.) the communication source (PC/Handheld device/PLC) the communication medium (wireless/fibre/copper) control flow (if leak test fails, unit is diverted to repair station) Basically, the model will be used as a focus different groups on outstanding tasks; for example, I'm interested in the DB and any front-end app needed, process engineers need to be thinking about the workflow and liaising with the PLC suppliers, the other IT guys need to make sure we have the hardware and comms in place. Obviously I could just improvise in Visio, but I was wondering if there was a particular modelling technique that might particularly suit my needs or my audience. I'm thinking of a visual model with supporting documentation (as little as possible, as much as is necessary). Clearly, I don't want something that will take me ages to (effectively) learn, nor one that will alienate non-technical members of the project team. So far I've had brief looks at BPMN, EPC Diagrams, standard Flow Diagrams... and I've forgotten most of what I used to know about UML... And I'm not against picking and mixing... as long as it is quick, clear and effective. Conclusion: In the end, I opted for a quasi-workflow/dataflow diagram. I mapped out the parts of the manufacturing process that interact with the traceability DB, and indicated in a significantly-simplified form, the data flows and DB activity. Alongside which, I have a supporting document which outlines each process, the data being transacted for each process (a 'data dictionary' of sorts) and details of hardware and connectivity required. I can't decide whether is a product of genius or a crime against established software development practices, but I do think that is will hit the mark for this particular audience.

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  • Sorting objects before rendering

    - by dreta
    I'm trying to implement a scene graph and in all the articles i've come across there is talk about object sorting. So you'd sort your objects by "material" for example. Now untill i sat down and started implementing it, i kind of took this for granted, because it made sense. But now i'm wondering what does sorting actually change? In my engine, i have a manager for UBOs, i use those to store data that'll be shared between programs, at the moment that only involves time, camera and projection matrices and lights (i'm not worrying about managing which lights affect which objects ATM). Now for each model i have to change the model to world matrix uniform, no sorting is going to change that. So is the jump from changing this matrix to also setting a material for each object that bad? I vaguely remember reading somewhere that each time you change something in the pipeline, it has to get flushed and that can cause performance issues. But for each drawing call i'm setting up a model to world matrix anyway, so what sense does it make to ever be concerned about this? BTW is there any information about whether changing a uniform and calling glBufferSubData is more (or less) expensive.

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  • Does this syntax for specifying Django conditional form display align with python/django convention?

    - by andy
    I asked a similar question on Stackoverflow and was told it was better asked here. So I'll ask it slightly rephrased. I am working on a Django project, part of which will become a distributable plugin that allows the python/django developer to specify conditional form field display logic in the form class or model class. I am trying to decide how the developer must specify that logic. Here's an example: class MyModel(models.Model): #these are some django model fields which will be used in a form yes_or_no = models.SomeField...choices are yes or no... why = models.SomeField...text, but only relevant if yes_or_no == yes... elaborate_even_more = models.SomeField...more text, just here so we can have multiple conditions #here i am inventing some syntax...i am looking for suggestions!! #this is one possibility why.show_if = ('yes_or_no','==','yes') elaborate_even_more.show_if = (('yes_or_no','==','yes'),('why','is not','None')) #help me choose a syntax that is *easy*...and Pythonic and...Djangonic...and that makes your fingers happy to type! #another alternative... conditions = {'why': ('yes_or_no','==','yes'), 'elaborate_even_more': (('yes_or_no','==','yes'),('why','is not','None')) } #or another alternative... """Showe the field whiche hath the name *why* only under that circumstance in whiche the field whiche hath the name *yes_or_no* hath the value *yes*, in strictest equality.""" etc... Those conditions will be eventually passed via django templates to some javascript that will show or hide form fields accordingly. Which of those options (or please propose a better option) aligns better with conventions such that it will be easiest for the python/django developer to use? Also are there other considerations that should impact what syntax I choose?

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  • Go/Obj-C style interfaces with ability to extend compiled objects after initial release

    - by Skrylar
    I have a conceptual model for an object system which involves combining Go/Obj-C interfaces/protocols with being able to add virtual methods from any unit, not just the one which defines a class. The idea of this is to allow Ruby-ish open classes so you can take a minimalist approach to library development, and attach on small pieces of functionality as is actually needed by the whole program. Implementation of this involves a table of methods marked virtual in an RTTI table, which system functions are allowed to add to during module initialization. Upon typecasting an object to an interface, a Go-style lookup is done to create a vtable for that particular mapping and pass it off so you can have comparable performance to C/C++. In this case, methods may be added /afterwards/ which were not previously known and these new methods allow newer interfaces to be satisfied; while I like this idea because it seems like it would be very flexible (disregarding the potential for spaghetti code, which can happen with just about any model you use regardless). By wrapping the system calls for binding methods up in a set of clean C-compatible calls, one would also be able to integrate code with shared libraries and retain a decent amount of performance (Go does not do shared linking, and Objective-C does a dynamic lookup on each call.) Is there a valid use-case for this model that would make it worth the extra background plumbing? As much as this Dylan-style extensibility would be nice to have access to, I can't quite bring myself to a use case that would justify the overhead other than "it could make some kinds of code more extensible in future scenarios."

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  • Raspberry Pi Now Shipping with 512MB RAM; Still Only $35

    - by Jason Fitzpatrick
    Fans of the tiny Raspberry Pi will be pleased to hear the new version of their Model B board now ships with 512MB of RAM (up from the previous 256MB). The best part about the upgrade? The price point stays at $35 a board. From the official Raspberry Pi blog: One of the most common suggestions we’ve heard since launch is that we should produce a more expensive “Model C” version of Raspberry Pi with extra RAM. This would be useful for people who want to use the Pi as a general-purpose computer, with multiple large applications running concurrently, and would enable some interesting embedded use cases (particularly using Java) which are slightly too heavyweight to fit comfortably in 256MB. The downside of this suggestion for us is that we’re very attached to $35 as our highest price point. With this in mind, we’re pleased to announce that from today all Model B Raspberry Pis will ship with 512MB of RAM as standard. If you have an outstanding order with either distributor, you will receive the upgraded device in place of the 256MB version you ordered. Units should start arriving in customers’ hands today, and we will be making a firmware upgrade available in the next couple of days to enable access to the additional memory. We’re excited to get our hands on a new board and try out Raspbmc with that extra RAM. HTG Explains: What is the Windows Page File and Should You Disable It? How To Get a Better Wireless Signal and Reduce Wireless Network Interference How To Troubleshoot Internet Connection Problems

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  • Displaying a Paged Grid of Data in ASP.NET MVC

    This article demonstrates how to display a paged grid of data in an ASP.NET MVC application and builds upon the work done in two earlier articles: Displaying a Grid of Data in ASP.NET MVC and Sorting a Grid of Data in ASP.NET MVC. Displaying a Grid of Data in ASP.NET MVC started with creating a new ASP.NET MVC application in Visual Studio, then added the Northwind database to the project and showed how to use Microsoft's Linq-to-SQL tool to access data from the database. The article then looked at creating a Controller and View for displaying a list of product information (the Model). Sorting a Grid of Data in ASP.NET MVC enhanced the application by adding a view-specific Model (ProductGridModel) that provided the View with the sorted collection of products to display along with sort-related information, such as the name of the database column the products were sorted by and whether the products were sorted in ascending or descending order. The Sorting a Grid of Data in ASP.NET MVC article also walked through creating a partial view to render the grid's header row so that each column header was a link that, when clicked, sorted the grid by that column. In this article we enhance the view-specific Model (ProductGridModel) to include paging-related information to include the current page being viewed, how many records to show per page, and how many total records are being paged through. Next, we create an action in the Controller that efficiently retrieves the appropriate subset of records to display and then complete the exercise by building a View that displays the subset of records and includes a paging interface that allows the user to step to the next or previous page, or to jump to a particular page number, we create and use a partial view that displays a numeric paging interface Like with its predecessors, this article offers step-by-step instructions and includes a complete, working demo available for download at the end of the article. Read on to learn more! Read More >

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  • Oh snap! My RPi was upgraded to 512MB! Woo-hoo!

    - by hinkmond
    I ordered a Raspberry Pi Model B (256MB) over 4 months ago on backorder. When it finally came I saw it was upgraded to the new half a gig model! Woot! But, all was not perfect. Gary C. told me the shipped configuration of the new RPi models didn't have the right firmware for 512MB, and I had to upgrade the start.elf in the /boot directory to recognize all of the 512MB RAM. I did a "free" command, and sure enough saw only 240MB. Sadness. But, Gary gave me a copy of his start.elf which worked after some trail and error. For anyone ordering the new RPi Model B w/512MB, here are the steps to get you going with full 512MB RAM: sudo apt-get update --fix-missing sudo apt-get upgrade --fix-missing # NOTE: This step takes at least a couple hours on a # fast network wget https://raw.github.com/raspberrypi/firmware/\ 164b0fe2b3b56081c7510df93bc1440aebe45f7e/boot/\ arm496_start.elf sudo mv /boot/start.elf /boot/orig-start.elf sudo mv arm496_start.elf /boot/start.elf sudo reboot free total used free shared buffers cached Mem: 497768 210596 287172 0 16892 169624 -/+ buffers/cache: 24080 473688 Swap: 102396 0 102396 So of course this means... (drumroll) there is now 498MB available for the Java Embedded heap! java -Xmx400m -version java version "1.7.0_06" Java(TM) SE Embedded Runtime Environment (build 1.7.0_06-b24, headless) Java HotSpot(TM) Embedded Client VM (build 23.2-b09, mixed mode) Yeah, baby! Hinkmond

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  • Who can change the View in MVC?

    - by Luke
    I'm working on a thick client graph displaying and manipulation application. I'm trying to apply the MVC pattern to our 3D visualization component. Here is what I have for the Model, View, and Controller: Model - The graph and it's metadata. This includes vertices, edges, and the attributes of each. It does not contain position information, icons, colors, or anything display related. View - This would commonly be called a scene graph. It includes the 3D display information, texture information, color information, and anything else that is related specifically to the visualization of the model. Controller - The controller takes the view and displays it in a Window using OpenGL (but it could potentially be any 3D graphics package). The application has various "layouts" that change the position of the vertices in the display. For instance, one layout may arrange the vertices in a circle. Is it common for these layouts to access and change the view directly? Should they go through the Controller to access the View? If they go through the Controller, should they just ask for direct access to the View or should each change go through the controller? I realize this is a bit different from the standard MVC example where there a finite number of Views. In this case, the View can change in an infinite number of ways. Perhaps I'm shattering some basic principle of MVC here. Thanks in advance!

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  • Is there a canonical source supporting "all-surrogates"?

    - by user61852
    Background The "all-PK-must-be-surrogates" approach is not present in Codd's Relational Model or any SQL Standard (ANSI, ISO or other). Canonical books seems to elude this restrictions too. Oracle's own data dictionary scheme uses natural keys in some tables and surrogate keys in other tables. I mention this because these people must know a thing or two about RDBMS design. PPDM (Professional Petroleum Data Management Association) recommend the same canonical books do: Use surrogate keys as primary keys when: There are no natural or business keys Natural or business keys are bad ( change often ) The value of natural or business key is not known at the time of inserting record Multicolumn natural keys ( usually several FK ) exceed three columns, which makes joins too verbose. Also I have not found canonical source that says natural keys need to be immutable. All I find is that they need to be very estable, i.e need to be changed only in very rare ocassions, if ever. I mention PPDM because these people must know a thing or two about RDBMS design too. The origins of the "all-surrogates" approach seems to come from recommendations from some ORM frameworks. It's true that the approach allows for rapid database modeling by not having to do much business analysis, but at the expense of maintainability and readability of the SQL code. Much prevision is made for something that may or may not happen in the future ( the natural PK changed so we will have to use the RDBMS cascade update funtionality ) at the expense of day-to-day task like having to join more tables in every query and having to write code for importing data between databases, an otherwise very strightfoward procedure (due to the need to avoid PK colisions and having to create stage/equivalence tables beforehand ). Other argument is that indexes based on integers are faster, but that has to be supported with benchmarks. Obviously, long, varying varchars are not good for PK. But indexes based on short, fix-length varchar are almost as fast as integers. The questions - Is there any canonical source that supports the "all-PK-must-be-surrogates" approach ? - Has Codd's relational model been superceded by a newer relational model ?

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  • Enforcing Constraints Upon Data Documents of Various Formats

    - by Christopher Berman
    This seems like the sort of problem that must have been solved elegantly long ago, but I haven't the foggiest how to google it and find it. Suppose you're maintaining a large legacy system, which has a large collection of data (tens of GB) of various formats, including XML and two different internal configuration formats. Suppose further that there are abstract rules governing the values these files may or may not contain. EXAMPLE: File A defines the raw, mathematical data pertaining to the aerodynamics of a car for consumption of the physics component of the system. File B contains certain values from File A in an easily accessible, XML hierarchy for consumption of a different component of the system. There exists, therefore, an abstract rule (or constraint) such that the values from File B must match the values from File A. This is probably the simplest constraint that can be specified, but in practice, the constraints between files can become very complicated indeed. What is the best method for managing these constraints between files of arbitrary formats, short of migrating it over to an RDBMS (which simply isn't feasible for the foreseeable future)? Has this problem been solved already? To be more specific, I would expect the solution to at least produce notifications of violated constraints; the solution need not resolve the constraints. ============================== Sample file structures File A (JeepWrangler2011.emv): MODEL JeepWrangler2011 { EsotericMathValueX 11.1 EsotericMathValueY 22.2 EsotericMathValueZ 33.3 } File B (JeepWrangler2011.xml): <model name="JeepWrangler2011"> <!--These values must correspond File A's EsotericMathValues--> <modelExtent x="11.1" y="22.2" z="33.3"/> [...] </model>

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  • Particle trajectory smoothing: where to do the simulation?

    - by nkint
    I have a particle system in which I have particles that are moving to a target and the new targets are received via network. The list of new target are some noisy coordinates of a moving target stored in the server that I want to smooth in the client. For doing the smoothing and the particle I wrote a simple particle engine with standard euler integration model. So, my pseudo code is something like that: # pseudo code class Particle: def update(): # do euler motion model integration: # if the distance to the target is more than a limit # add a new force to the accelleration # seeking the target, # and add the accelleration to velocity # and velocity to the position positionHistory.push_back(position); if history.length > historySize : history.pop_front() class ParticleEngine: particleById = dict() # an associative array # where the keys are the id # and particle istances are sotred as values # this method is called each time a new tcp packet is received and parsed def setNetTarget(int id, Vec2D new_target): particleById[id].setNewTarget(new_target) # this method is called each new frame def draw(): for p in particleById.values: p.update() beginVertex(LINE_STRIP) for v in p.positionHistory: vertex(v.x, v.y) endVertex() The new target that are arriving are noisy but setting some accelleration/velocity parameters let the particle to have a smoothed trajectories. But if a particle trajectory is a circle after a while the particle position converge to the center (a normal behaviour of euler integration model). So I decided to change the simulation and use some other interpolation (spline?) or smooth method (kalman filter?) between the targets. Something like: switch( INTERPOLATION_MODEL ): case EULER_MOTION: ... case HERMITE_INTERPOLATION: ... case SPLINE_INTERPOLATION: ... case KALMAN_FILTER_SMOOTHING: ... Now my question: where to write the motion simulation / trajectory interpolation? In the Particle? So I will have some Particle subclass like ParticleEuler, ParticleSpline, ParticleKalman, etc..? Or in the particle engine?

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  • Authenticate with Django 1.5

    - by gorjuce
    I'm currently testing django 1.5 and a custom User model, but I've some problems. I've created a User class in my account app, which looks like: class User(AbstractBaseUser): email = models.EmailField() activation_key = models.CharField(max_length=255) is_active = models.BooleanField(default=False) is_admin = models.BooleanField(default=False) USERNAME_FIELD = 'email' I can correctly register a user, who is stored in my account_user table. Now, how can I log in? I've tried with: def login(request): form = AuthenticationForm() if request.method == 'POST': form = AuthenticationForm(request.POST) email = request.POST['username'] password = request.POST['password'] user = authenticate(username=email, password=password) if user is not None: if user.is_active: login(user) else: message = 'disabled account, check validation email' return render( request, 'account-login-failed.html', {'message': message} ) return render(request, 'account-login.html', {'form': form}) I can correctly register a new User My forms.py which contains my register form class RegisterForm(forms.ModelForm): """ a form to create user""" password = forms.CharField( label="Password", widget=forms.PasswordInput() ) password_confirm = forms.CharField( label="Password Repeat", widget=forms.PasswordInput() ) class Meta: model = User exclude = ('last_login', 'activation_key') def clean_password_confirm(self): password = self.cleaned_data.get("password") password_confirm = self.cleaned_data.get("password_confirm") if password and password_confirm and password != password_confirm: raise forms.ValidationError("Password don't math") return password_confirm def clean_email(self): if User.objects.filter(email__iexact=self.cleaned_data.get("email")): raise forms.ValidationError("email already exists") return self.cleaned_data['email'] def save(self): user = super(RegisterForm, self).save(commit=False) user.password = self.cleaned_data['password'] user.activation_key = generate_sha1(user.email) user.save() return user My question is: Why does authenticate give me None? I know I'm trying to authenticate() with an email as username but is that not one of the reasons to use a custom User model?

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