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• How to see "anti if" movement and its gaol?

  - by Vijay Shanker

  I have a developer for last 3 years, have been using if-else or if-else if statements a lot in my programing habit. And today, I found This link. One obvious sample i put here public void doSomthing(String target, String object){ //validate requests if(target != null && target.trim().length() < 1){ //invalid request; } //further logic } Now, I have seen this sort of check all over the places, libraries. So, I wanted to have a discussion about the worthiness of such a movement. Please let me know your views.

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• How to make 2 incompatible types, but with the same members, interchangeable?

  - by Quigrim

  Yesterday 2 of the guys on our team came to me with an uncommon problem. We are using a third-party component in one of our winforms applications. All the code has already been written against it. They then wanted to incorporate another third-party component, by the same vender, into our application. To their delight they found that the second component had the exact same public members as the first. But to their dismay, the 2 components have completely separate inheritance hierarchies, and implement no common interfaces. Makes you wonder... Well, makes me wonder. An example of the problem: public class ThirdPartyClass1 { public string Name { get { return "ThirdPartyClass1"; } } public void DoThirdPartyStuff () { Console.WriteLine ("ThirdPartyClass1 is doing its thing."); } } public class ThirdPartyClass2 { public string Name { get { return "ThirdPartyClass2"; } } public void DoThirdPartyStuff () { Console.WriteLine ("ThirdPartyClass2 is doing its thing."); } } Gladly they felt copying and pasting the code they wrote for the first component was not the correct answer. So they were thinking of assigning the component instant into an object reference and then modifying the code to do conditional casts after checking what type it was. But that is arguably even uglier than the copy and paste approach. So they then asked me if I can write some reflection code to access the properties and call the methods off the two different object types since we know what they are, and they are exactly the same. But my first thought was that there goes the elegance. I figure there has to be a better, graceful solution to this problem.

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• How to Effectively Create Bullet Patterns

  - by SoulBeaver

  I'm currently creating a top-down shooter like Touhou. The most important factor of the game is that there are many diverse patterns and ways at which bullets are generated and shot at the player, see this video: http://www.youtube.com/watch?v=4Nb5Ohbt1Sg#start=0:60;end=9:53; At the moment, I'm using a class "Pattern" which has a series of steps on moving and shooting. However, I feel this method is quite laborous as I have to create a new Pattern for each attack and perhaps new Bullet classes that will implement a certain behavior. This question received a comment suggesting I should look into BulletML for easy creation and storage of bullets with a specific pattern. It looks decent, but it led me to wonder, what other solutions do you have that I should take into consideration? Update My current design is as follows: An example of an implemented pattern: My GigasPattern first executes a teleport which moves Alice to a certain point (X, Y) on the screen. After this is completed, the pattern starts using the Mover to move the sprite around (whereas teleporting has separate effects and animation). These are of no concern, really, as they are quite simple. The Shooter also creates various Attacks, which are classes again that the Shooter can use to create various patterns of bullets, much like the one in the question I posted. Once the Mover has reached it's destination, both it and the shooter stop and return to an inactive state. The pattern completes, is removed by the AI and a new one gets chosen.

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• JavaScript Class Patterns

  - by Liam McLennan

  To write object-oriented programs we need objects, and likely lots of them. JavaScript makes it easy to create objects: var liam = { name: "Liam", age: Number.MAX_VALUE }; But JavaScript does not provide an easy way to create similar objects. Most object-oriented languages include the idea of a class, which is a template for creating objects of the same type. From one class many similar objects can be instantiated. Many patterns have been proposed to address the absence of a class concept in JavaScript. This post will compare and contrast the most significant of them. Simple Constructor Functions Classes may be missing but JavaScript does support special constructor functions. By prefixing a call to a constructor function with the ‘new’ keyword we can tell the JavaScript runtime that we want the function to behave like a constructor and instantiate a new object containing the members defined by that function. Within a constructor function the ‘this’ keyword references the new object being created -  so a basic constructor function might be: function Person(name, age) { this.name = name; this.age = age; this.toString = function() { return this.name + " is " + age + " years old."; }; } var john = new Person("John Galt", 50); console.log(john.toString()); Note that by convention the name of a constructor function is always written in Pascal Case (the first letter of each word is capital). This is to distinguish between constructor functions and other functions. It is important that constructor functions be called with the ‘new’ keyword and that not constructor functions are not. There are two problems with the pattern constructor function pattern shown above: It makes inheritance difficult The toString() function is redefined for each new object created by the Person constructor. This is sub-optimal because the function should be shared between all of the instances of the Person type. Constructor Functions with a Prototype JavaScript functions have a special property called prototype. When an object is created by calling a JavaScript constructor all of the properties of the constructor’s prototype become available to the new object. In this way many Person objects can be created that can access the same prototype. An improved version of the above example can be written: function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { toString: function() { return this.name + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); In this version a single instance of the toString() function will now be shared between all Person objects. Private Members The short version is: there aren’t any. If a variable is defined, with the var keyword, within the constructor function then its scope is that function. Other functions defined within the constructor function will be able to access the private variable, but anything defined outside the constructor (such as functions on the prototype property) won’t have access to the private variable. Any variables defined on the constructor are automatically public. Some people solve this problem by prefixing properties with an underscore and then not calling those properties by convention. function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { _getName: function() { return this.name; }, toString: function() { return this._getName() + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); Note that the _getName() function is only private by convention – it is in fact a public function. Functional Object Construction Because of the weirdness involved in using constructor functions some JavaScript developers prefer to eschew them completely. They theorize that it is better to work with JavaScript’s functional nature than to try and force it to behave like a traditional class-oriented language. When using the functional approach objects are created by returning them from a factory function. An excellent side effect of this pattern is that variables defined with the factory function are accessible to the new object (due to closure) but are inaccessible from anywhere else. The Person example implemented using the functional object construction pattern is: var personFactory = function(name, age) { var privateVar = 7; return { toString: function() { return name + " is " + age * privateVar / privateVar + " years old."; } }; }; var john2 = personFactory("John Lennon", 40); console.log(john2.toString()); Note that the ‘new’ keyword is not used for this pattern, and that the toString() function has access to the name, age and privateVar variables because of closure. This pattern can be extended to provide inheritance and, unlike the constructor function pattern, it supports private variables. However, when working with JavaScript code bases you will find that the constructor function is more common – probably because it is a better approximation of mainstream class oriented languages like C# and Java. Inheritance Both of the above patterns can support inheritance but for now, favour composition over inheritance. Summary When JavaScript code exceeds simple browser automation object orientation can provide a powerful paradigm for controlling complexity. Both of the patterns presented in this article work – the choice is a matter of style. Only one question still remains; who is John Galt?

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• JavaScript Class Patterns

  - by Liam McLennan

  To write object-oriented programs we need objects, and likely lots of them. JavaScript makes it easy to create objects: var liam = { name: "Liam", age: Number.MAX_VALUE }; But JavaScript does not provide an easy way to create similar objects. Most object-oriented languages include the idea of a class, which is a template for creating objects of the same type. From one class many similar objects can be instantiated. Many patterns have been proposed to address the absence of a class concept in JavaScript. This post will compare and contrast the most significant of them. Simple Constructor Functions Classes may be missing but JavaScript does support special constructor functions. By prefixing a call to a constructor function with the ‘new’ keyword we can tell the JavaScript runtime that we want the function to behave like a constructor and instantiate a new object containing the members defined by that function. Within a constructor function the ‘this’ keyword references the new object being created -  so a basic constructor function might be: function Person(name, age) { this.name = name; this.age = age; this.toString = function() { return this.name + " is " + age + " years old."; }; } var john = new Person("John Galt", 50); console.log(john.toString()); Note that by convention the name of a constructor function is always written in Pascal Case (the first letter of each word is capital). This is to distinguish between constructor functions and other functions. It is important that constructor functions be called with the ‘new’ keyword and that not constructor functions are not. There are two problems with the pattern constructor function pattern shown above: It makes inheritance difficult The toString() function is redefined for each new object created by the Person constructor. This is sub-optimal because the function should be shared between all of the instances of the Person type. Constructor Functions with a Prototype JavaScript functions have a special property called prototype. When an object is created by calling a JavaScript constructor all of the properties of the constructor’s prototype become available to the new object. In this way many Person objects can be created that can access the same prototype. An improved version of the above example can be written: function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { toString: function() { return this.name + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); In this version a single instance of the toString() function will now be shared between all Person objects. Private Members The short version is: there aren’t any. If a variable is defined, with the var keyword, within the constructor function then its scope is that function. Other functions defined within the constructor function will be able to access the private variable, but anything defined outside the constructor (such as functions on the prototype property) won’t have access to the private variable. Any variables defined on the constructor are automatically public. Some people solve this problem by prefixing properties with an underscore and then not calling those properties by convention. function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { _getName: function() { return this.name; }, toString: function() { return this._getName() + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); Note that the _getName() function is only private by convention – it is in fact a public function. Functional Object Construction Because of the weirdness involved in using constructor functions some JavaScript developers prefer to eschew them completely. They theorize that it is better to work with JavaScript’s functional nature than to try and force it to behave like a traditional class-oriented language. When using the functional approach objects are created by returning them from a factory function. An excellent side effect of this pattern is that variables defined with the factory function are accessible to the new object (due to closure) but are inaccessible from anywhere else. The Person example implemented using the functional object construction pattern is: var john = new Person("John Galt", 50); console.log(john.toString()); var personFactory = function(name, age) { var privateVar = 7; return { toString: function() { return name + " is " + age * privateVar / privateVar + " years old."; } }; }; var john2 = personFactory("John Lennon", 40); console.log(john2.toString()); Note that the ‘new’ keyword is not used for this pattern, and that the toString() function has access to the name, age and privateVar variables because of closure. This pattern can be extended to provide inheritance and, unlike the constructor function pattern, it supports private variables. However, when working with JavaScript code bases you will find that the constructor function is more common – probably because it is a better approximation of mainstream class oriented languages like C# and Java. Inheritance Both of the above patterns can support inheritance but for now, favour composition over inheritance. Summary When JavaScript code exceeds simple browser automation object orientation can provide a powerful paradigm for controlling complexity. Both of the patterns presented in this article work – the choice is a matter of style. Only one question still remains; who is John Galt?

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• Which book should I pick to improve my program designs/design patterns?

  - by zxcvbnm

  I want to learn about design patterns and from what I've seen the most recommended ones are the Gang of Four's Design Patterns and Head First Design Patterns. There are also language specific books, but I never see them recommended. I suppose it ties you to whatever strengths/weaknesses are inherent to each language, so not a good idea to learn design patterns in general. The Gang of Four's book is kinda old, so I'm wondering if there isn't a better alternative out today? I've heard the Heard First one isn't quite as good. But I'm not sure why, so it's really hard to pick either one. I've see some answers on this very site recommending both, but if I can only read one, which should I pick? I've been coding for 3+ years, though I've never had a good class on this subject. Also, would a book like Code Complete help me with this? One more thing: how often are these techniques supposed to be useful? For example, this question has me wondering if this stuff is worth the trouble. And please, tell me more than just "read x". I'd like to know why you're suggesting x.

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• MSDN Magazine: Patterns for High Availability, Scalability, and Computing Power with Windows Azure

  In this article, Joshy Joseph, a principal architect with Microsoft Services Managed Solutions Group, examines the typical cloud platform architecture and some common architectural patterns, along with their implementation on the Windows Azure offering from Microsoft....Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Integration Patterns with Azure Service Bus Relay, Part 3: Anonymous partial-trust consumer

  - by Elton Stoneman

  This is the third in the IPASBR series, see also: Integration Patterns with Azure Service Bus Relay, Part 1: Exposing the on-premise service Integration Patterns with Azure Service Bus Relay, Part 2: Anonymous full-trust .NET consumer As the patterns get further from the simple .NET full-trust consumer, all that changes is the communication protocol and the authentication mechanism. In Part 3 the scenario is that we still have a secure .NET environment consuming our service, so we can store shared keys securely, but the runtime environment is locked down so we can't use Microsoft.ServiceBus to get the nice WCF relay bindings. To support this we will expose a RESTful endpoint through the Azure Service Bus, and require the consumer to send a security token with each HTTP service request. Pattern applicability This is a good fit for scenarios where: the runtime environment is secure enough to keep shared secrets the consumer can execute custom code, including building HTTP requests with custom headers the consumer cannot use the Azure SDK assemblies the service may need to know who is consuming it the service does not need to know who the end-user is Note there isn't actually a .NET requirement here. By exposing the service in a REST endpoint, anything that can talk HTTP can be a consumer. We'll authenticate through ACS which also gives us REST endpoints, so the service is still accessed securely. Our real-world example would be a hosted cloud app, where we we have enough room in the app's customisation to keep the shared secret somewhere safe and to hook in some HTTP calls. We will be flowing an identity through to the on-premise service now, but it will be the service identity given to the consuming app - the end user's identity isn't flown through yet. In this post, we’ll consume the service from Part 1 in ASP.NET using the WebHttpRelayBinding. The code for Part 3 (+ Part 1) is on GitHub here: IPASBR Part 3. Authenticating and authorizing with ACS We'll follow the previous examples and add a new service identity for the namespace in ACS, so we can separate permissions for different consumers (see walkthrough in Part 1). I've named the identity partialTrustConsumer. We’ll be authenticating against ACS with an explicit HTTP call, so we need a password credential rather than a symmetric key – for a nice secure option, generate a symmetric key, copy to the clipboard, then change type to password and paste in the key: We then need to do the same as in Part 2 , add a rule to map the incoming identity claim to an outgoing authorization claim that allows the identity to send messages to Service Bus: Issuer: Access Control Service Input claim type: http://schemas.xmlsoap.org/ws/2005/05/identity/claims/nameidentifier Input claim value: partialTrustConsumer Output claim type: net.windows.servicebus.action Output claim value: Send As with Part 2, this sets up a service identity which can send messages into Service Bus, but cannot register itself as a listener, or manage the namespace. RESTfully exposing the on-premise service through Azure Service Bus Relay The part 3 sample code is ready to go, just put your Azure details into Solution Items\AzureConnectionDetails.xml and “Run Custom Tool” on the .tt files.  But to do it yourself is very simple. We already have a WebGet attribute in the service for locally making REST calls, so we are just going to add a new endpoint which uses the WebHttpRelayBinding to relay that service through Azure. It's as easy as adding this endpoint to Web.config for the service:         <endpoint address="https://sixeyed-ipasbr.servicebus.windows.net/rest"                   binding="webHttpRelayBinding"                    contract="Sixeyed.Ipasbr.Services.IFormatService"                   behaviorConfiguration="SharedSecret">         </endpoint> - and adding the webHttp attribute in your endpoint behavior:           <behavior name="SharedSecret">             <webHttp/>             <transportClientEndpointBehavior credentialType="SharedSecret">               <clientCredentials>                 <sharedSecret issuerName="serviceProvider"                               issuerSecret="gl0xaVmlebKKJUAnpripKhr8YnLf9Neaf6LR53N8uGs="/>               </clientCredentials>             </transportClientEndpointBehavior>           </behavior> Where's my WSDL? The metadata story for REST is a bit less automated. In our local webHttp endpoint we've enabled WCF's built-in help, so if you navigate to: http://localhost/Sixeyed.Ipasbr.Services/FormatService.svc/rest/help - you'll see the uri format for making a GET request to the service. The format is the same over Azure, so this is where you'll be connecting: https://[your-namespace].servicebus.windows.net/rest/reverse?string=abc123 Build the service with the new endpoint, open that in a browser and you'll get an XML version of an HTTP status code - a 401 with an error message stating that you haven’t provided an authorization header: <?xml version="1.0"?><Error><Code>401</Code><Detail>MissingToken: The request contains no authorization header..TrackingId:4cb53408-646b-4163-87b9-bc2b20cdfb75_5,TimeStamp:10/3/2012 8:34:07 PM</Detail></Error> By default, the setup of your Service Bus endpoint as a relying party in ACS expects a Simple Web Token to be presented with each service request, and in the browser we're not passing one, so we can't access the service. Note that this request doesn't get anywhere near your on-premise service, Service Bus only relays requests once they've got the necessary approval from ACS. Why didn't the consumer need to get ACS authorization in Part 2? It did, but it was all done behind the scenes in the NetTcpRelayBinding. By specifying our Shared Secret credentials in the consumer, the service call is preceded by a check on ACS to see that the identity provided is a) valid, and b) allowed access to our Service Bus endpoint. By making manual HTTP requests, we need to take care of that ACS check ourselves now. We do that with a simple WebClient call to the ACS endpoint of our service; passing the shared secret credentials, we will get back an SWT: var values = new System.Collections.Specialized.NameValueCollection(); values.Add("wrap_name", "partialTrustConsumer"); //service identity name values.Add("wrap_password", "suCei7AzdXY9toVH+S47C4TVyXO/UUFzu0zZiSCp64Y="); //service identity password values.Add("wrap_scope", "http://sixeyed-ipasbr.servicebus.windows.net/"); //this is the realm of the RP in ACS var acsClient = new WebClient(); var responseBytes = acsClient.UploadValues("https://sixeyed-ipasbr-sb.accesscontrol.windows.net/WRAPv0.9/", "POST", values); rawToken = System.Text.Encoding.UTF8.GetString(responseBytes); With a little manipulation, we then attach the SWT to subsequent REST calls in the authorization header; the token contains the Send claim returned from ACS, so we will be authorized to send messages into Service Bus. Running the sample Navigate to http://localhost:2028/Sixeyed.Ipasbr.WebHttpClient/Default.cshtml, enter a string and hit Go! - your string will be reversed by your on-premise service, routed through Azure: Using shared secret client credentials in this way means ACS is the identity provider for your service, and the claim which allows Send access to Service Bus is consumed by Service Bus. None of the authentication details make it through to your service, so your service is not aware who the consumer is (MSDN calls this "anonymous authentication").

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• Google I/O 2012 - Go Concurrency Patterns

  Google I/O 2012 - Go Concurrency Patterns Rob Pike Concurrency is the key to designing high performance network services. Go's concurrency primitives (goroutines and channels) provide a simple and efficient means of expressing concurrent execution. In this talk we see how tricky concurrency problems can be solved gracefully with simple Go code. For all I/O 2012 sessions, go to developers.google.com From: GoogleDevelopers Views: 169 2 ratings Time: 51:27 More in Science & Technology

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• Are there any good videos out there on Java Design Patterns?

  - by Becky Reamy

  My team would like to spend some time at lunch learning design patterns. Previously, we watched some videos on Javascript which we found very useful as a way to start discussions. We would like to do the same thing with design patterns so that we don't have to spend a lot of time (outside of work) researching individual patterns in order to give a presentation. I did a little searching and came up fairly empty handed. Any help would be appreciated. It doesn't even have to be a video, even something that we can listen to (maybe a book on tape even).

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• Tablet design guide, Endeca patterns now available

  - by JuergenKress

  UX Direct, an Oracle program that offers consultants, partners, and customers the same scientifically proven and reusable user experience best practices that Oracle uses to build Oracle Applications, recently added links to a new design guide for creating tablet-based solutions for enterprise applications, and to the recently published Endeca User Interface Design Pattern Library. The tablet design guide is available from the UX Direct Home page. Tap the button under “Latest patterns & tools” for “Oracle Applications UX Tablet Guide.” It provides basic help for designers, developers, and project managers trying to approach tablet design and testing from an enterprise point of view. To hear what developers are saying about it, follow the links from this post on the User Experience Assistance blog. The newly released Endeca User Interface Design Pattern Library is also available from the UX Direct Home page and from a post on the User Experience Assistance blog. It describes principled ways to solve common user interface (UI) design problems related to search, faceted navigation, and discovery. The link between Simplified UI and Oracle UX strategy, plus content you can share on the cloud, ADf, tailoring, and more Simplified User Interface in Oracle Fusion Applications Fronts Oracle Cloud Offerings This new article on Simplified UI has just been posted on Usable Apps. Learn about the three themes - simplicity, mobility, and extensibility – that Simplified UI embodies. These same principles are guiding the development of the next generation of the Oracle user experience. Oracle's Applications User Experience Strategy: One Cloud User Experience, with Optimized UIs Where and How You Want This podcast from Misha Vaughan, Director, User Experience, is now available on the Oracle University Knowledge Center. It is available for partners and Oracle employees at this iLearning Link. Oracle Partner Builds User Experience That Hits Right Note for New Employees This new article on the Usable Apps website explores the experience of consultants at IntraSee as they implement a PeopleSoft onboarding process for Invesco, a global asset management company. The Feng Shui of Fusion This article in Oracle Scene is from Grant Ronald, Director of Product Management, on the Tools of Fusion: Oracle JDeveloper and Oracle ADF. Hands-On Workshop with Fusion Applications and ADF UX Desktop Design Patterns This post on the Voice of User Experience, or VoX, blog from Misha Vaughan describes a new kind of workshop for partners and a handful of internal Oracle sales folks on extending Oracle Fusion Applications and building custom applications with Application Development Framework (ADF) while maintaining the Oracle user experience. To learn more about the content that was delivered during this three-day workshop, visit the Usable Apps blog. Recent posts from a new blog series take a look at several of the topics discussed during the workshop. Applications User Experience Fundamentals Visual Design for any Enterprise User Interface / Art School in a Box Wireframing / Blueprinting Usable Applications Concepts. Tailoring videos This blog post from Richard Bingham, Applications Architect, on the Fusion Applications Developer Relations blog provides links to several videos that show many customization and development tasks using the Oracle Fusion Applications platform. SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Facebook Wiki Mix Forum Technorati Tags: UX,Architecture,SOA Community,Oracle SOA,Oracle BPM,Community,OPN,Jürgen Kress

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• free design patterns templates to use for Visual Paradigm?

  - by ajsie

  i know that you can create your own design patterns and save them for later use. but i wonder if there are free templates you can download and use, eg. factory, singleton and so on. then you dont have to recreate/copy-paste and you will have accurate patterns.

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• What is the relationship between delegate, proxy and adapter patterns?

  - by Siegfried

  What is the relationship between delegate, proxy and adapter patterns? It seems they are all similar in terms of doing something on behalf of another object. Can anyone summarize the relationship and difference between these 3 patterns? Thanks!

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• Overwhelmed by design patterns... where to begin?

  - by Pete

  I am writing a simple prototype code to demonstrate & profile I/O schemes (HDF4, HDF5, HDF5 using parallel IO, NetCDF, etc.) for a physics code. Since focus is on IO, the rest of the program is very simple: class Grid { public: floatArray x,y,z; }; class MyModel { public: MyModel(const int &nip1, const int &njp1, const int &nkp1, const int &numProcs); Grid grid; map<string, floatArray> plasmaVariables; }; Where floatArray is a simple class that lets me define arbitrary dimensioned arrays and do mathematical operations on them (i.e. x+y is point-wise addition). Of course, I could use better encapsulation (write accessors/setters, etc.), but that's not the concept I'm struggling with. For the I/O routines, I am envisioning applying simple inheritance: Abstract I/O class defines read & write functions to fill in the "myModel" object HDF4 derived class HDF5 HDF5 using parallel IO NetCDF etc... The code should read data in any of these formats, then write out to any of these formats. In the past, I would add an AbstractIO member to myModel and create/destroy this object depending on which I/O scheme I want. In this way, I could do something like: myModelObj.ioObj->read('input.hdf') myModelObj.ioObj->write('output.hdf') I have a bit of OOP experience but very little on the Design Patterns front, so I recently acquired the Gang of Four book "Design Patterns: Elements of Reusable Object-Oriented Software". OOP designers: Which pattern(s) would you recommend I use to integrate I/O with the myModel object? I am interested in answering this for two reasons: To learn more about design patterns in general Apply what I learn to help refactor an large old crufty/legacy physics code to be more human-readable & extensible. I am leaning towards applying the Decerator pattern to myModel, so I can attach the I/O responsibilities dynamically to myModel (i.e. whether to use HDF4, HDF5, etc.). However, I don't feel very confident that this is the best pattern to apply. Reading the Gang of Four book cover-to-cover before I start coding feels like a good way to develop an unhealthy caffeine addiction. What patterns do you recommend?

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• Are all of the core J2EE patterns still good in context of JEE?

  - by Harry

  With the arrival of JEE and EJB 3, have any of these Core J2EE Patterns become obsolete, or stand deprecated in light of (better) alternatives? Are there any new patterns that one could use? Thanks...

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• Virtual Brown Bag Recap: JB's New Gem, Patterns 101, Killing VS, CodeMav

  - by Brian Schroer

  At this week's Virtual Brown Bag meeting: JB showed off his new SpeakerRate Ruby gem Claudio alerted us to the Refactoring Manifesto We answered the question "How do I get started with Design Patterns?" Ever had to kill a frozen instance of Visual Studio? Yeah, I thought so. Claudio showed us how to do it with PowerShell. (It's faster) JB previewed his new CodeMav web site, which will be a social network for developers (integration with Speaker Rate, slide share, github, StackOverflow, etc.) For detailed notes, links, and the video recording, go to the VBB wiki page: https://sites.google.com/site/vbbwiki/main_page/2011-01-06

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• Attend free workshop on 3/16: Architecture Analysis Patterns

  On Tuesday, 3/16/2010, Headspring is offering another free monthly workshop.  This month, I am leading the workshop, and the topic is: Architecture Analysis Patterns: How to reason about the structure of an application Layering, a fundamental concept of software architecture: Layer helps to separate dependencies and to decouple concerns. Most of the industry does layering in name only. It's lip service. In 23 slides and accompanying commentary, we will explore the fundamental concept of separating...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Cloud Computing Architecture Patterns: Don’t Focus on the Client

  - by BuckWoody

  Normally I try to put topics in the positive in other words "Do this" not "Don't do that". Sometimes its clearer to focus on what *not* to do. Popular development processes often start with screen mockups, or user input descriptions. In a scale-out pattern like Cloud Computing on Windows Azure, that's the wrong place to start. Start with the Data    Instead, I recommend that you start with the data that a process requires. That data might be temporary or persisted, but starting with the data and its requirements helps to define not only the storage engine you need but also drives everything from security to the integrity of the application. For instance, assume the requirements show that the user must enter their phone number, and that this datum is used in a contact management system further down the application chain. For that datum, you can determine what data type you need (U.S. only or International?) the security requirements, whether it needs ACID compliance, how it will be searched, indexed and so on. From one small data point you can extrapolate out your options for storing and processing the data. Here's the interesting part, which begins to break the patterns that we've used for decades: all of the data doesn't have the same requirements. The phone number might be best suited for a list, or an element, or a string, with either BASE or ACID requirements, based on how it is used. That means we don't have to dump everything into XML, an RDBMS, a NoSQL engine, or a flat file exclusively. In fact, one record might use all of those depending on the use-case requirements. Next Is Data Management  With the data defined, we can move on to how to store the data. Again, the requirements now dictate whether we need a full relational calculus or set-based operations, or we can choose another method based on the requirements for the data. And breaking another pattern its OK to store in more than once, in more than one location. We do this all the time for reporting systems and Business Intelligence systems, so this is a pattern we need to think about even for OLTP data. Move to Data Transport How does the data get around? We can use a connection-based method, sending the data along a transport to the storage engine, but in some cases we may want to use a cache, a queue, the Service Bus, or Complex Event Processing. Finally, Data Processing Most RDBMS engines, NoSQL, and certainly Big Data engines not only store data, but can process and manipulate it as well. Its doubtful that you'll calculate that phone number right? Well, if you're the phone company, you most certainly will. And so we see that even once we've chosen the data type, storage and engine, the same element can have different computing requirements based on how it is used. Sure, We Need A Front-End At Some Point Not all data is entered by human hands in fact most data isn't. We don't really need a Graphical User Interface (GUI) we need some way for a GUI to get data into and out of the systems listed earlier.   But when we do need to allow users to enter or examine data, that should be left to the GUI that best fits the device the user has. Ever tried to use an application designed for a web browser on a phone? Or one designed for a tablet on a phone? Its usually quite painful. The siren song of "We'll just write one interface for all devices" is strong, and has beguiled many an unsuspecting architect. But they just don't work out.   Instead, focus on the data, its transport and processing. Create API calls or a message system that allows for resilient transport to the device or interface, and let it do what it does best. References Microsoft Architecture Journal:   http://msdn.microsoft.com/en-us/architecture/bb410935.aspx Patterns and Practices:   http://msdn.microsoft.com/en-us/library/ff921345.aspx Windows Azure iOS, Android, Windows 8 Mobile Devices SDK: http://www.windowsazure.com/en-us/develop/mobile/tutorials/get-started-ios/ Windows Azure Facebook SDK: http://ntotten.com/2013/03/14/using-windows-azure-mobile-services-with-the-facebook-sdk-for-windows-phone/

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• Design Pattern Books, Papers or Resources for Non-Object Orientated Paradigms?

  - by FinnNk

  After viewing this video on InfoQ about functional design patterns I was wondering what resources are out there on design patterns for non-object orientated paradigms. There are plenty out there for the OO world (GOF, etc, etc) and for architecture (EoEAA, etc, etc) but I'm not aware of what's out there for functional, logic, or other programming paradigms. Is there anything? A comment during the video suggests possibly not - does anyone know better? (By the way, by design patterns I don't mean language features or data structures but higher level approaches to designing an application - as discussed in the linked video)

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• Removing surrounding noises from voice recording

  - by Peak Reconstruction Wavelength

  I have a wave file whose frequency spectrum looks like this. http://i.stack.imgur.com/2rRaS.png It contains audio, which I want to keep while removing the rest. The problem is that the surround noise changes, just those distinct voice patterns remain. I marked the voice patterns for clarity: http://i.stack.imgur.com/eLkBl.png What could an algorithm look like / a workflow in adobe audition look like that removes everything but the voice patterns? I think that the main characteristic is the line-shaped form over time. Loudness alone is not enough as the noise is loud aswell.

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• Processing a list of atomic operations, allowing for interruptions

  - by JDB

  I'm looking for a design pattern that addresses the following situation: There exists a list of tasks that must be processed. Tasks may be added at any time. Each task is wholly independent from all other tasks. The order in which tasks are processed has no effect on the overall system or on the tasks themselves. Every task must be processed once and only once. The "main" process which launches the task processors may start and stop without warning. When stopped, the "main" process loses all in-memory data. Obviously this is going to involve some state, but are there any design patterns which discuss where and how to maintain that state? Are there any relevant anti-patterns? Named patterns are especially helpful so that we can discuss this topic with other organizations without having to describe the entire problem domain.

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• DDD East Anglia, 29th June 2013 - Async Patterns presentation and source code

  - by Liam Westley

  Originally posted on: http://geekswithblogs.net/twickers/archive/2013/07/01/ddd-east-anglia-29th-june-2013---async-patterns-presentation.aspxMany thanks to the team in Cambridge for an awesome first conference DDD East Anglia.  I definitely appreciate how each of the different areas have their own distinctive atmosphere and feel.  Thanks to some great sponsors we enjoyed a great venue and some excellent nibbles. For those who attended my Async my source code and presentation are available on GitHub, https://github.com/westleyl/DDDEastAnglia2013-Async.git If you are new to Git then the easiest client to install is GitHub for Windows, a graphical UI for accessing GitHub. Personally, I also have Git Extensions and Tortoise Git installed. Tortoise Git is the file explorer add-in that works in a familiar manner to TortoiseSVN. As I mentioned during the presentation I have not included the sample data, the music files, in the source code placed on GitHub but I have included instructions on how to download them from http://silents.bandcamp.comand place them in the correct folders. Also, Windows Media Player, by default, does not play Ogg Vorbis and Flac music files, however you can download the codec installer for these, for free, from http://xiph.org/dshow. I have included the .Net 4.0 version of the source code that uses the Microsoft.Bcl.Async NuGet package - once you have got the project from GitHub you will need to install this NuGet package for the code to compile. Load Project into Visual Studio 2012 Access the NuGet package manager (Tools -> Library Package Manager -> Manage NuGet Packages For Solution) Highlight Online and then Search Online for microsoft.bcl.async Click on Install button Resources : You can download the Task-based Asynchronous Pattern white paper by Stephen Toub, which was the inspiration for this presentation from here - http://www.microsoft.com/en-us/download/details.aspx?id=19957 Presentation : If you just want the presentation and don’t want to bother with a GitHub login you can download the PowerPoint presentation from here.

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• JavaScript Class Patterns Revisited: Endgame

  - by Liam McLennan

  I recently described some of the patterns used to simulate classes (types) in JavaScript. But I missed the best pattern of them all. I described a pattern I called constructor function with a prototype that looks like this: function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { toString: function() { return this.name + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); and I mentioned that the problem with this pattern is that it does not provide any encapsulation, that is, it does not allow private variables. Jan Van Ryswyck recently posted the solution, obvious in hindsight, of wrapping the constructor function in another function, thereby allowing private variables through closure. The above example becomes: var Person = (function() { // private variables go here var name,age; function constructor(n, a) { name = n; age = a; } constructor.prototype = { toString: function() { return name + " is " + age + " years old."; } }; return constructor; })(); var john = new Person("John Galt", 50); console.log(john.toString()); Now we have prototypal inheritance and encapsulation. The important thing to understand is that the constructor, and the toString function both have access to the name and age private variables because they are in an outer scope and they become part of the closure.

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• MVC design patterns

  - by insane-36

  I have an application and it does not use a very good structure. However it seems to me that I have tried to stick to mvc design pattern but a senior engineer claims that I have no design patterns and code are mesh. How I have structured the code : I have couple of nsmanagedobject model classes which represents model in my case and a reskit library which encapsulates the nsurlconnection and url request. I fetch the request from the view controller itself and then when the request get completed I create predicate and then populate it in tableview. Wherever I need custom view either I create it in nib or create in a custom subclass of UIView. I have use delegation pattern and notification to communication to view controller, views and block callback with restkit. But, the senior engineer is very new to ios. He has been doing it for 2 months now but he is a good java programmer. So, what is mvc pattern ? Is core data model not working as a model objects, view controller as controller and views. I dont seem to find any other places or any other cases to create my own model object since the most of the models are used as NSManagedObject subclass.

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• Book Review (Book 11) - Applied Architecture Patterns on the Microsoft Platform

  - by BuckWoody

  This is a continuation of the books I challenged myself to read to help my career - one a month, for year. You can read my first book review here, and the entire list is here. The book I chose for April 2012 was: Applied Architecture Patterns on the Microsoft Platform. I was traveling at the end of last month so I’m a bit late posting this review here. Why I chose this book: I actually know a few of the authors on this book, so when they told me about it I wanted to check it out. The premise of the book is exactly as it states in the title - to learn how to solve a problem using products from Microsoft. What I learned: I liked the book - a lot. They've arranged the content in a "Solution Decision Framework", that presents a few elements to help you identify a need and then propose alternate solutions to solve them, and then the rationale for the choice. But the payoff is that the authors then walk through the solution they implement and what they ran into doing it. I really liked this approach. It's not a huge book, but one I've referred to again since I've read it. It's fairly comprehensive, and includes server-oriented products, not things like Microsoft Office or other client-side tools. In fact, I would LOVE to have a work like this for Open Source and other vendors as well - would make for a great library for a Systems Architect. This one is unashamedly aimed at the Microsoft products, and even if I didn't work here, I'd be fine with that. As I said, it would be interesting to see some books on other platforms like this, but I haven't run across something that presents other systems in quite this way. And that brings up an interesting point - This book is aimed at folks who create solutions within an organization. It's not aimed at Administrators, DBA's, Developers or the like, although I think all of those audiences could benefit from reading it. The solutions are made up, and not to a huge level of depth - nor should they be. It's a great exercise in thinking these kinds of things through in a structured way. The information is a bit dated, especially for Windows and SQL Azure. While the general concepts hold, the cloud platform from Microsoft is evolving so quickly that any printed book finds it hard to keep up with the improvements. I do have one quibble with the text - the chapters are a bit uneven. This is always a danger with multiple authors, but it shows up in a couple of chapters. I winced at one of the chapters that tried to take a more conversational, humorous style. This kind of academic work doesn't lend itself to that style. I recommend you get the book - and use it. I hope they keep it updated - I'll be a frequent customer. :)  

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