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• Question about design (inheritance, polymorphism)

  - by Dan

  Hi, I have a question about a problem I'm struggling with. Hope you can bear with me. Imagine I have an Object class representing the base class of a hierarchy of physical objects. Later I inherit from it to create an Object1D, Object2D and Object3D classes. Each of these derived classes will have some specific methods and attributes. For example, the 3d object might have functionality to download a 3d model to be used by a renderer. So I'd have something like this: class Object {}; class Object1D : public Object { Point mPos; }; class Object2D : public Object { ... }; class Object3D : public Object { Model mModel; }; Now I'd have a separate class called Renderer, which simply takes an Object as argument and well, renders it :-) In a similar way, I'd like to support different kinds of renderers. For instance, I could have a default one that every object could rely on, and then provide other specific renderers for some kind of objects: class Renderer {}; // Default one class Renderer3D : public Renderer {}; And here comes my problem. A renderer class needs to get an Object as an argument, for example in the constructor in order to retrieve whatever data it needs to render the object. So far so good. But a Renderer3D would need to get an Object3D argument, in order to get not only the basic attributes but also the specific attributes of a 3d object. Constructors would look like this: CRenderer(Object& object); CRenderer3D(Object3D& object); Now how do I specify this in a generic way? Or better yet, is there a better way to design this? I know I could rely on RTTI or similar but I'd like to avoid this if possible as I feel there is probably a better way to deal with this. Thanks in advance!

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• Objective-c design advice for use of different data sources, swapping between test and live

  - by user200341

  I'm in the process of designing an application that is part of a larger piece of work, depending on other people to build an API that the app can make use of to retrieve data. While I was thinking about how to setup this project and design the architecture around it, something occurred to me, and I'm sure many people have been in similar situations. Since my work is depending on other people to complete their tasks, and a test server, this slows work down at my end. So the question is: What's the best practice for creating test repositories and classes, implementing them, and not having to depend on altering several places in the code to swap between the test classes and the actual repositories / proper api calls. Contemplate the following scenario: GetDataFromApiCommand *getDataCommand = [[GetDataFromApiCommand alloc]init]; getDataCommand.delegate = self; [getDataCommand getData]; Once the data is available via the API, "GetDataFromApiCommand" could use the actual API, but until then a set of mock data could be returned upon the call of [getDataCommand getData] There might be multiple instances of this, in various places in the code, so replacing all of them wherever they are, is a slow and painful process which inevitably leads to one or two being overlooked. In strongly typed languages we could use dependency injection and just alter one place. In objective-c a factory pattern could be implemented, but is that the best route to go for this? GetDataFromApiCommand *getDataCommand = [GetDataFromApiCommandFactory buildGetDataFromApiCommand]; getDataCommand.delegate = self; [getDataCommand getData]; What is the best practices to achieve this result? Since this would be most useful, even if you have the actual API available, to run tests, or work off-line, the ApiCommands would not necessarily have to be replaced permanently, but the option to select "Do I want to use TestApiCommand or ApiCommand". It is more interesting to have the option to switch between: All commands are test and All command use the live API, rather than selecting them one by one, however that would also be useful to do for testing one or two actual API commands, mixing them with test data. EDIT The way I have chosen to go with this is to use the factory pattern. I set up the factory as follows: @implementation ApiCommandFactory + (ApiCommand *)newApiCommand { // return [[ApiCommand alloc]init]; return [[ApiCommandMock alloc]init]; } @end And anywhere I want to use the ApiCommand class: GetDataFromApiCommand *getDataCommand = [ApiCommandFactory newApiCommand]; When the actual API call is required, the comments can be removed and the mock can be commented out. Using new in the message name implies that who ever uses the factory to get an object, is responsible for releasing it (since we want to avoid autorelease on the iPhone). If additional parameters are required, the factory needs to take these into consideration i.e: [ApiCommandFactory newSecondApiCommand:@"param1"]; This will work quite well with repositories as well.

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• C# MultiThread Safe Class Design

  - by Robert

  I'm trying to designing a class and I'm having issues with accessing some of the nested fields and I have some concerns with how multithread safe the whole design is. I would like to know if anyone has a better idea of how this should be designed or if any changes that should be made? using System; using System.Collections; namespace SystemClass { public class Program { static void Main(string[] args) { System system = new System(); //Seems like an awkward way to access all the members dynamic deviceInstance = (((DeviceType)((DeviceGroup)system.deviceGroups[0]).deviceTypes[0]).deviceInstances[0]); Boolean checkLocked = deviceInstance.locked; //Seems like this method for accessing fields might have problems with multithreading foreach (DeviceGroup dg in system.deviceGroups) { foreach (DeviceType dt in dg.deviceTypes) { foreach (dynamic di in dt.deviceInstances) { checkLocked = di.locked; } } } } } public class System { public ArrayList deviceGroups = new ArrayList(); public System() { //API called to get names of all the DeviceGroups deviceGroups.Add(new DeviceGroup("Motherboard")); } } public class DeviceGroup { public ArrayList deviceTypes = new ArrayList(); public DeviceGroup() {} public DeviceGroup(string deviceGroupName) { //API called to get names of all the Devicetypes deviceTypes.Add(new DeviceType("Keyboard")); deviceTypes.Add(new DeviceType("Mouse")); } } public class DeviceType { public ArrayList deviceInstances = new ArrayList(); public bool deviceConnected; public DeviceType() {} public DeviceType(string DeviceType) { //API called to get hardwareIDs of all the device instances deviceInstances.Add(new Mouse("0001")); deviceInstances.Add(new Keyboard("0003")); deviceInstances.Add(new Keyboard("0004")); //Start thread CheckConnection that updates deviceConnected periodically } public void CheckConnection() { //API call to check connection and returns true this.deviceConnected = true; } } public class Keyboard { public string hardwareAddress; public bool keypress; public bool deviceConnected; public Keyboard() {} public Keyboard(string hardwareAddress) { this.hardwareAddress = hardwareAddress; //Start thread to update deviceConnected periodically } public void CheckKeyPress() { //if API returns true this.keypress = true; } } public class Mouse { public string hardwareAddress; public bool click; public Mouse() {} public Mouse(string hardwareAddress) { this.hardwareAddress = hardwareAddress; } public void CheckClick() { //if API returns true this.click = true; } } }

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• Map Library: Client-side or Server-side?

  - by Mahdi

  As I have already asked here, I have to implement a Multi-Platform Map application. Now I have Mapstraction as an option which uses Javascript to implement the desired functionality. My question is, "Is there any reason/benefit to implement such a library (let say, Adapters) in Server-side (in my case, PHP)?" As these maps are all based on Javascript, there is a big reason to use Javascript again to make the adapter also, so it would not be dependent to PHP, Java, or .NET for example. But is that all? I wish to hear your ideas and comments also. :)

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• Using design-patterns to transform web-service model classes into local model classes and vise versa

  - by Daniil Petrov

  There is a web-application built with play framework 1.2.7. It contains less than 10 model classes. The main purpose of the application is a lightweight access to a complex remote application (more than 50 model classes). The remote application has its own SOAP API and we use it for synchronization of data. There is a scheduled job in the web-app which makes requests to the remote app. It gets bunches of objects from the remote model and populates corresponding objects of the local model. Currently, there are two groups of classes - the local model and the remote model (generated from wsdl schema). It is not allowed to make any modifications to the remote model. Transformations are being made in the scheduled job class. When it gets objects from the remote app it creates local objects. Recently, it was decided to add a possibility to modify the remote objects. It requires more transformations on our side. We need to transform from remote to local model when reading objects and from local to remote when changing objects. I wonder if this would be possible to use some design-patterns to reduce a number of transformations?

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• Object oriented design importance

  - by user5507

  I started studying Object Oriented Design and Modelling using the this book by James Rumbaugh. It uses a tool called Object Modeling Technique (OMT). I have certain newbie questions. I searched the net, but couldn't get answers The book is pretty old. Don't know why the school told me to learn this. I know OMT is a predecessor of the Unified Modeling Language (UML). So its a waste? Whether the concepts change very much when we move from OMT to UML? I know OMT has Object, Dynamic and Functional Model. Wikipedia says UML is compatible with OMT and UML is a model too. As per wikipedia the UML models are Static and Dynamic and they are represented by different diagrams like class, object, activity, sequence..... I couldn't find the equivalence of this in OMT. I read that there are many object oriented development methods like OMT, Booch,.... Which one is used by Industry ? Where could I get a comparison of different Object oriented development methods?

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• Design pattern for window management in a Java Swing app

  - by Lord Torgamus

  I've just started creating my very first little Java Swing app. When the program opens, it brings up a single, simple window with a label and a couple buttons. Clicking one of those buttons is supposed to wipe out the welcome screen and replace it with a totally different panel. I'm not sure what the best way to create that functionality is. One method would be to pass my JFrame as an argument into... just about every other component, but that feels hacky to me. Or, there's making each panel double as an action listener, but that doesn't seem right, either. Is there a design pattern I should be applying here? "Replace the contents of the main — and only — window" must be a reasonably common operation. A name for the pattern would be enough; I can use Google on my own from there. (I wouldn't say no to a longer explanation, though.)

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• Which of these design patterns is superior?

  - by durron597

  I find I tend to design class structures where several subclasses have nearly identical functionality, but one piece of it is different. So I write nearly all the code in the abstract class, and then create several subclasses to do the one different thing. Does this pattern have a name? Is this the best way for this sort of scenario? Option 1: public interface TaxCalc { String calcTaxes(); } public abstract class AbstractTaxCalc implements TaxCalc { // most constructors and fields are here public double calcTaxes(UserFinancials data) { // code double diffNumber = getNumber(data); // more code } abstract protected double getNumber(UserFinancials data); protected double initialTaxes(double grossIncome) { // code return initialNumber; } } public class SimpleTaxCalc extends AbstractCalc { protected double getNumber(UserFinancials data) { double temp = intialCalc(data.getGrossIncome()); // do other stuff return temp; } } public class FancyTaxCalc extends AbstractTaxCalc { protected double getNumber(UserFinancials data) { int temp = initialCalc(data.getGrossIncome()); // Do fancier math return temp; } } Option 2: This version is more like the Strategy pattern, and should be able to do essentially the same sorts of tasks. public class TaxCalcImpl implements TaxCalc { private final TaxMath worker; public DummyImpl(TaxMath worker) { this.worker = worker; } public double calcTaxes(UserFinancials data) { // code double analyzedDouble = initialNumber; int diffNumber = worker.getNumber(data, initialNumber); // more code } protected int initialTaxes(double grossIncome) { // code return initialNumber; } } public interface TaxMath { double getNumber(UserFinancials data, double initial); } Then I could do: TaxCalc dum = new TaxCalcImpl(new TaxMath() { @Override public double getNumber(UserFinancials data, double initial) { double temp = data.getGrossIncome(); // do math return temp; }); And I could make specific implementations of TaxMath for things I use a lot, or I could make a stateless singleton for certain kinds of workers I use a lot. So the question I'm asking is: Which of these patterns is superior, when, and why? Or, alternately, is there an even better third option?

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• Android threads trouble wrapping my head around design

  - by semajhan

  I am having trouble wrapping my head around game design. On the android platform, I have an activity and set its content view with a custom surface view. The custom surface view acts as my panel and I create instances of all classes and do all the drawing and calculation in there. Question: Should I instead create the instances of other classes in my activity? Now I create a custom thread class that handles the game loop. Question: How do I use this one class in all my activities? Or do I have to create a separate instance of the extended thread class each time? In my previous game, I had multiple levels that had to create an instance of the thread class and in the thread class I had to set constructor methods for each separate level and in the loop use a switch statement to check which level it needs to render and update. Sorry if that sounds confusing. I just want to know if the method I am using is inefficient (which it probably is) and how to go about designing it the correct way. I have read many tutorials out there and I am still having lots of trouble with this particular topic. Maybe a link to a some tutorials that explain this? Thanks.

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• Examples of limitations in IT due to different bit length by design

  - by Alaudo

  I am teaching the course "Introduction in Programming" for the first-year students and would like to find interesting examples where the datatype size in bits, chosen by design, led to certain known restrictions or important values. Here are some examples: Due to the fact that the Bell teleprinter used 7-bit-code (later accepted as ASCII) until now have we often to encode attachments in electronic messages to contain only 7 bit data. Classical limitation of 32-bit address space leads to the 4Gb maximal RAM size available for 32-bit systems and 4Gb maximal file size in FAT32. Do you know some other interesting examples how the choice of the data type (and especially its binary length) influenced the modern IT world. Added after some discussion in comments: I am not going to teach how to overcome limitations. I just want them to know that 1 byte can hold the values from -127..0..+127 o 0..255, 2 bytes cover the range 0..65535 etc by proving examples they know from other sources, like the above-mentioned base64 encoding etc. We are just learning the basic datatypes and I am trying to find a good reference for "how large" these types are.

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• Android threads trouble wrapping my head around design

  - by semajhan

  I am having trouble wrapping my head around game design. On the android platform, I have an activity and set its content view with a custom surface view. The custom surface view acts as my panel and I create instances of all classes and do all the drawing and calculation in there. Question: Should I instead create the instances of other classes in my activity? Now I create a custom thread class that handles the game loop. Question: How do I use this one class in all my activities? Or do I have to create a separate thread each time? In my previous game, I had multiple levels that had to create an instance of the thread class and in the thread class I had to set constructor methods for each separate level and in the loop use a switch statement to check which level it needs to render and update. Sorry if that sounds confusing. I just want to know if the method I am using is inefficient (which it probably is) and how to go about designing it the correct way. I have read many tutorials out there and I am still having lots of trouble with this particular topic. Maybe a link to a some tutorials that explain this? Thanks.

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• 5 Mac Applications For Web And Graphic Design

  - by Jyoti

  In this article free applications useful and effective for the development and creation of websites with your Mac computer. Without further ado, here are 5 Excellent Mac Application for Web and Graphic Design. Fotoflexer : Fotoflexer claims to be “The world’s most advanced online image editor”. It offers completely free access to numerous features such as photo effects, graphics, shapes, morphing, and the creation of collages. You can also integrate and share your art with social sites like MySpace, Flickr, Facebook, and more. This can be an important app if the site you are creating is going to use applications. Simple CSS : With Simple CSS you can create Cascading Style Sheets from scratch or edit them right from the comfort of your desktop. Update styles on multiple pages all at once and reduce the data transfer usage on your page for faster loads. Blender : Blender is an open source software that allows you to create 3D animation with interactive playback leaves you with the option to optimize the style of your site with a few graphics. You can create animations with shades of colors, glossy features, soft shadows and advanced rendering features. JAlbum : Jalbum is a very useful app that allows you to create stylish photo galleries to publish on the web. All you have to do is simply drag selected folders into a pane where any images contained within the folder will automatically be arranged into a photo gallery. You can add several different themes and templates to enhance the appearance of your gallery, later then gain the HTML code and publish the complete gallery onto the web. Colorate : With Colorate you can create harmonized color palettes along with color schemes. Generate these palettes for images, photographs and more.

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• Office design and layout for agile development

  - by Adam Eberbach

  (moved from stackoverflow) I have found lot of discussions here on about which keyboard, desk, light or colored background is best - but I can't find one addressing the layout of the whole office. We are a company with about 20 employees moving to a new place, something larger. There are two main development practices going on here with regular combination, the back end people often needing to work with the mobile people to arrange web services. There are about twice as many back end people as mobile people. About half of the back end developers are working on-site at any time and while they are almost never all in the office at once at least 5-10 spaces need to be provided - so most of the time the two groups are about equal. We have the chance to arrange desks, partitions and possibly even walls to make the space good. There won't be cash for dot-com frills like catering or massages but now's the time to be planning to avoid ending up with a bunch of desks in a long line. Joel on Software's Bionic Office is an article I've remembered from way back and it has some good ideas but I* (and more importantly the company's owners) are not completely sold on the privacy idea in an environment where we are supposed to be collaborating. This is another great link - The Ultimate Software Development Office Layout - I hadn't even remembered enclosed meeting rooms until reading this. Does the private office stand in the way of agile development? Is the scrum enough forced contact and if you need to bug someone you should need to get up and knock on their door? What design layouts can you point to and why would you recommend them? *I'm not against closed offices at all but would be happy if some other solution can do just as well. If it can't... well, that's what this question is all about.

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• iOS chat application design, sending/relaying the message over to the end user

  - by AyBayBay

  I have a design question. Let us say you were tasked with building a chat application, specifically for iOS (iOS Chat Application). For simplicity let us say you can only chat with one person at a time (no group chat functionality). How then can you achieve sending a message directly to an end user from phone A to phone B? Obviously there is a web service layer with some API calls. One of the API calls available will be startChat(). After starting a chat, when you send a message, you make another async call, let us call it sendMessage() and pass in a string with your message. Once it goes to the web service layer, the message gets stored in a database. Here is where I am currently stuck. After the message gets sent to the web service layer, how do we then achieve sending/relaying the message over to the end user? Should the web server send out a message to the end user and notify them, or should each client call a receiveMessage() method periodically, and if the server side has some info for them it can then respond with that info? Finally, how can we handle the case in which the user you are trying to send a message to is offline? How can we make sure the end user gets the packet when he moves back to an area with signal?

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• Decorator not calling the decorated instance - alternative design needed

  - by Daniel Hilgarth

  Assume I have a simple interface for translating text (sample code in C#): public interface ITranslationService { string GetTranslation(string key, CultureInfo targetLanguage); // some other methods... } A first simple implementation of this interface already exists and simply goes to the database for every method call. Assuming a UI that is being translated at start up this results in one database call per control. To improve this, I want to add the following behavior: As soon as a request for one language comes in, fetch all translations from this language and cache them. All translation requests are served from the cache. I thought about implementing this new behavior as a decorator, because all other methods of that interface implemented by the decorater would simple delegate to the decorated instance. However, the implementation of GetTranslation wouldn't use GetTranslation of the decorated instance at all to get all translations of a certain language. It would fire its own query against the database. This breaks the decorator pattern, because every functionality provided by the decorated instance is simply skipped. This becomes a real problem if there are other decorators involved. My understanding is that a Decorator should be additive. In this case however, the decorator is replacing the behavior of the decorated instance. I can't really think of a nice solution for this - how would you solve it? Everything is allowed, even a complete re-design of ITranslationService itself.

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• Question about a simple design problem

  - by Uri

  At work I stumbled uppon a method. It made a query, and returned a String based on the result of the query, such as de ID of a customer. If the query didn't return a single customer, it'd return a null. Otherwise, it'd return a String with the ID's of them. It looked like this: String error = getOwners(); if (error != null) { throw new Exception("Can't delete, the flat is owned by: " + error); } ... Ignoring the fact that getCustomers() returns a null when it should instead return an empty String, two things are happening here. It checks if the flat is owned by someone, and then returns them. I think a more readable logic would be to do this: if (isOwned) { throw new Exception("Can't delete, the flat is owned by: " + getOwners()); } ... The problem is that the first way does with one query what I do with two queries to the database. What would be a good solution involving good design and efficiency for this?

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• Best design for a "Command Executer" class

  - by Justin984

  Sorry for the vague title, I couldn't think of a way to condense the question. I am building an application that will run as a background service and intermittently collect data about the system its running on. A second Android controller application will query the system over tcp/ip for statistics about the system. Currently, the background service has a tcp listener class that reads/writes bytes from a socket. When data is received, it raises an event to notify the service. The service takes the bytes, feeds them into a command parser to figure out what is being requested, and then passes the parsed command to a command executer class. When the service receives a "query statistics" command, it should return statistics over the tcp/ip connection. Currently, all of these classes are fully decoupled from each other. But in order for the command executer to return statistics, it will obviously need access to the socket somehow. For reasons I can't completely articulate, it feels wrong for the command executer to have a direct reference to the socket. I'm looking for strategies and/or design patterns I can use to return data over the socket while keeping the classes decoupled, if this is possible. Hopefully this makes sense, please let me know if I can include any info that would make the question easier to understand.

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• Design help with parallel process

  - by brazc0re

  I am re-factoring some code and an having an issue with retrieving data from two parallel processes. I have an application that sends packets back and forth via different mediums (ex: RS232, TCP/IP, etc). The jist if of this question is that there are two parallel processes going on. I hope the picture below displays what is going on better than I can word it: SetupRS232() class creates a new instance of the SerialPort by: SerialPort serialPort = new SerialPort(); My question is, what is the best way that the Communicator() class, which sends out the packet via the respective medium, get access to the SerialPort object from the SetupRS232 class? I can do it with a Singleton but have heard that they are generally not the best design to go by. I am trying to follow SRP but I do feel like I am doing something wrong here. Communicator() will need to go out of it's way to get access to SetupRS232() to get access to the SerialPort class. I actually haven't found a way to even get access to it. Would designing each medium class, for example, SetupRS232(), SetupTCPIP, as a singleton be the best way to approach this problem?

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• OOP Design: relationship between entity classes

  - by beginner_

  I have at first sight a simple issue but can't wrap my head around on how to solve. I have an abstract class Compound. A Compound is made up of Structures. Then there is also a Container which holds 1 Compound. A "special" implementation of Compound has Versions. For that type of Compound I want the Container to hold the Versionof the Compound and not the Compound itself. You could say "just create an interface Containable" and a Container holds 1 Containable. However that won't work. The reason is I'm creating a framework and the main part of that framework is to simplify storing and especially searching for special data type held by Structure objects. Hence to search for Containers which contain a Compound made up of a specific Structure requires that the "Path" from Containerto Structure is well defined (Number of relationships or joins). I hope this was understandable. My question is how to design the classes and relationships to be able to do what I outlined.

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• Need suggestion for Mutiple Windows application design

  - by King Chan

  This was previously posted in StackOverflow, I just moved to here... I am using VS2008, MVVM, WPF, Prism to make a mutiple window CRM Application. I am using MidWinow in my MainWindow, I want Any ViewModel would able to make request to MainWindow to create/add/close MidChildWindow, ChildWindow(from WPF Toolkit), Window (the Window type). ViewModel can get the DialogResult from the ChildWindow its excutes. MainWindow have control on all opened window types. Here is my current approach: I made Dictionary of each of the windows type and stores them into MainWindow class. For 1, i.e in a CustomerInformationView, its CustomerInformationViewModel can execute EditCommand and use EventAggregator to tell MainWindow to open a new ChildWindow. CustomerInformationViewModel: CustomerEditView ceView = new CustomerEditView (); CustomerEditViewModel ceViewModel = CustomerEditViewModel (); ceView.DataContext = ceViewModel; ChildWindow cWindow = new ChildWindow(); cWindow.Content = ceView; MainWindow.EvntAggregator.GetEvent<NewWindowEvent>().Publish(new WindowEventArgs(ceViewModel.ViewModeGUID, cWindow )); cWindow.Show(); Notice that all my ViewModel will generates a Guid for help identifies the ChildWindow from MainWindow's dictionary. Since I will only be using 1 View 1 ViewModel for every Window. For 2. In CustomerInformationViewModel I can get DialogResult by OnClosing event from ChildWindow, in CustomerEditViewModel can use Guid to tell MainWindow to close the ChildWindow. Here is little question and problems: Is it good idea to use Guid here? Or should I use HashKey from ChildWindow? My MainWindows contains windows reference collections. So whenever window close, it will get notifies to remove from the collection by OnClosing event. But all the Windows itself doesn't know about its associated Guid, so when I remove it, I have to search for every KeyValuePair to compares... I still kind of feel wrong associate ViewModel's Guid for ChildWindow, it would make more sense if ChildWindow has it own ID then ViewModel associate with it... But most important, is there any better approach on this design? How can I improve this better?

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• ASP.NET design not SOLID

  - by w0051977

  SOLID principles are described here: http://en.wikipedia.org/wiki/SOLID_%28object-oriented_design%29 I am developing a large ASP.NET app. The previous developer created a few very large classes each with lots of different purposes. It is very difficult to maintain and extend. The classes are deployed to the web server along with the code behind files etc. I want to share a small amount of the app with another application. I am considering moving all of the classes of the ASP.NET web app to a DLL, so the small subset of functionality can be shared. I realise it would be better to only share the classes which contain code to be shared but because of the dependencies this is proving to be very difficult e.g. class A contains code that should be shared, however class A contains references to classes B, C, D, E, F, G etc, so class A cannot be shared on its own. I am planning to refactor the code in the future. As a temporary solution I am planning to convert all the classes into a single class library. Is this a bad idea and if so, is there an alternative? as I don't have time to refactor at the moment.

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• Process for beginning a Ruby on Rails project

  - by Daniel Beardsley

  I'm about to begin a Ruby on Rails project and I'd love to hear how others go through the process of starting an application design. I have quite a bit of experience with RoR, but don't have that many starting from scratch with only a vision experiences and would appreciate the wisdom of others who've been there. I'm looking for an order of events, reasons for the order, and maybe why each part is important. I can think of a few starting points, but I'm not sure where it's best to begin Model design and relationships (entities, how they relate, and their attributes) Think of user use-cases (or story-boards) and implement the minimum to get these done Create Model unit-tests then create the necessary migrations and AR models to get the tests to pass Hack out the most basic version of the simplest part of your application and go from there Start with a template for a rails app (like http://github.com/thoughtbot/suspenders) Do the boring gruntwork first (User auth, session management, ...) ...

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• Solaris 11.1: Changes to included FOSS packages

  - by alanc

  Besides the documentation changes I mentioned last time, another place you can see Solaris 11.1 changes before upgrading is in the online package repository, now that the 11.1 packages have been published to http://pkg.oracle.com/solaris/release/, as the “0.175.1.0.0.24.2” branch. (Oracle Solaris Package Versioning explains what each field in that version string means.) When you’re ready to upgrade to the packages from either this repo, or the support repository, you’ll want to first read How to Update to Oracle Solaris 11.1 Using the Image Packaging System by Pete Dennis, as there are a couple issues you will need to be aware of to do that upgrade, several of which are due to changes in the Free and Open Source Software (FOSS) packages included with Solaris, as I’ll explain in a bit. Solaris 11 can update more readily than Solaris 10 In the Solaris 10 and older update models, the way the updates were built constrained what changes we could make in those releases. To change an existing SVR4 package in those releases, we created a Solaris Patch, which applied to a given version of the SVR4 package and replaced, added or deleted files in it. These patches were released via the support websites (originally SunSolve, now My Oracle Support) for applying to existing Solaris 10 installations, and were also merged into the install images for the next Solaris 10 update release. (This Solaris Patches blog post from Gerry Haskins dives deeper into that subject.) Some of the restrictions of this model were that package refactoring, changes to package dependencies, and even just changing the package version number, were difficult to do in this hybrid patch/OS update model. For instance, when Solaris 10 first shipped, it had the Xorg server from X11R6.8. Over the first couple years of update releases we were able to keep it up to date by replacing, adding, & removing files as necessary, taking it all the way up to Xorg server release 1.3 (new version numbering begun after the X11R7 split of the X11 tree into separate modules gave each module its own version). But if you run pkginfo on the SUNWxorg-server package, you’ll see it still displayed a version number of 6.8, confusing users as to which version was actually included. We stopped upgrading the Xorg server releases in Solaris 10 after 1.3, as later versions added new dependencies, such as HAL, D-Bus, and libpciaccess, which were very difficult to manage in this patching model. (We later got libpciaccess to work, but HAL & D-Bus would have been much harder due to the greater dependency tree underneath those.) Similarly, every time the GNOME team looked into upgrading Solaris 10 past GNOME 2.6, they found these constraints made it so difficult it wasn’t worthwhile, and eventually GNOME’s dependencies had changed enough it was completely infeasible. Fortunately, this worked out for both the X11 & GNOME teams, with our management making the business decision to concentrate on the “Nevada” branch for desktop users - first as Solaris Express Desktop Edition, and later as OpenSolaris, so we didn’t have to fight to try to make the package updates fit into these tight constraints. Meanwhile, the team designing the new packaging system for Solaris 11 was seeing us struggle with these problems, and making this much easier to manage for both the development teams and our users was one of their big goals for the IPS design they were working on. Now that we’ve reached the first update release to Solaris 11, we can start to see the fruits of their labors, with more FOSS updates in 11.1 than we had in many Solaris 10 update releases, keeping software more up to date with the upstream communities. Of course, just because we can more easily update now, doesn’t always mean we should or will do so, it just removes the package system limitations from forcing the decision for us. So while we’ve upgraded the X Window System in the 11.1 release from X11R7.6 to 7.7, the Solaris GNOME team decided it was not the right time to try to make the jump from GNOME 2 to GNOME 3, though they did update some individual components of the desktop, especially those with security fixes like Firefox. In other parts of the system, decisions as to what to update were prioritized based on how they affected other projects, or what customer requests we’d gotten for them. So with all that background in place, what packages did we actually update or add between Solaris 11.0 and 11.1? Core OS Functionality One of the FOSS changes with the biggest impact in this release is the upgrade from Grub Legacy (0.97) to Grub 2 (1.99) for the x64 platform boot loader. This is the cause of one of the upgrade quirks, since to go from Solaris 11.0 to 11.1 on x64 systems, you first need to update the Boot Environment tools (such as beadm) to a new version that can handle boot environments that use the Grub2 boot loader. System administrators can find the details they need to know about the new Grub in the Administering the GRand Unified Bootloader chapter of the Booting and Shutting Down Oracle Solaris 11.1 Systems guide. This change was necessary to be able to support new hardware coming into the x64 marketplace, including systems using UEFI firmware or booting off disk drives larger than 2 terabytes. For both platforms, Solaris 11.1 adds rsyslog as an optional alternative to the traditional syslogd, and OpenSCAP for checking security configuration settings are compliant with site policies. Note that the support repo actually has newer versions of BIND & fetchmail than the 11.1 release, as some late breaking critical fixes came through from the community upstream releases after the Solaris 11.1 release was frozen, and made their way to the support repository. These are responsible for the other big upgrade quirk in this release, in which to upgrade a system which already installed those versions from the support repo, you need to either wait for those packages to make their way to the 11.1 branch of the support repo, or follow the steps in the aforementioned upgrade walkthrough to let the package system know it's okay to temporarily downgrade those. Developer Stack While Solaris 11.0 included Python 2.7, many of the bundled python modules weren’t packaged for it yet, limiting its usability. For 11.1, many more of the python modules include 2.7 versions (enough that I filtered them out of the below table, but you can always search on the package repository server for them. For other language runtimes and development tools, 11.1 expands the use of IPS mediated links to choose which version of a package is the default when the packages are designed to allow multiple versions to install side by side. For instance, in Solaris 11.0, GNU automake 1.9 and 1.10 were provided, and developers had to run them as either automake-1.9 or automake-1.10. In Solaris 11.1, when automake 1.11 was added, also added was a /usr/bin/automake mediated link, which points to the automake-1.11 program by default, but can be changed to another version by running the pkg set-mediator command. Mediated links were also used for the Java runtime & development kits in 11.1, changing the default versions to the Java 7 releases (the 1.7.0.x package versions), while allowing admins to switch links such as /usr/bin/javac back to Java 6 if they need to for their site, to deal with Java 7 compatibility or other issues, without having to update each usage to use the full versioned /usr/jdk/jdk1.6.0_35/bin/javac paths for every invocation. Desktop Stack As I mentioned before, we upgraded from X11R7.6 to X11R7.7, since a pleasant coincidence made the X.Org release dates line up nicely with our feature & code freeze dates for this release. (Or perhaps it wasn’t so coincidental, after all, one of the benefits of being the person making the release is being able to decide what schedule is most convenient for you, and this one worked well for me.) For the table below, I’ve skipped listing the packages in which we use the X11 “katamari” version for the Solaris package version (mainly packages combining elements of multiple upstream modules with independent version numbers), since they just all changed from 7.6 to 7.7. In the graphics drivers, we worked with Intel to update the Intel Integrated Graphics Processor support to support 3D graphics and kernel mode setting on the Ivy Bridge chipsets, and updated Nvidia’s non-FOSS graphics driver from 280.13 to 295.20. Higher up in the desktop stack, PulseAudio was added for audio support, and liblouis for Braille support, and the GNOME applications were built to use them. The Mozilla applications, Firefox & Thunderbird moved to the current Extended Support Release (ESR) versions, 10.x for each, to bring up-to-date security fixes without having to be on Mozilla’s agressive 6 week feature cycle release train. Detailed list of changes This table shows most of the changes to the FOSS packages between Solaris 11.0 and 11.1. As noted above, some were excluded for clarity, or to reduce noise and duplication. All the FOSS packages which didn't change the version number in their packaging info are not included, even if they had updates to fix bugs, security holes, or add support for new hardware or new features of Solaris. Package11.011.1 archiver/unrar 3.8.5 4.1.4 audio/sox 14.3.0 14.3.2 backup/rdiff-backup 1.2.1 1.3.3 communication/im/pidgin 2.10.0 2.10.5 compress/gzip 1.3.5 1.4 compress/xz not included 5.0.1 database/sqlite-3 3.7.6.3 3.7.11 desktop/remote-desktop/tigervnc 1.0.90 1.1.0 desktop/window-manager/xcompmgr 1.1.5 1.1.6 desktop/xscreensaver 5.12 5.15 developer/build/autoconf 2.63 2.68 developer/build/autoconf/xorg-macros 1.15.0 1.17 developer/build/automake-111 not included 1.11.2 developer/build/cmake 2.6.2 2.8.6 developer/build/gnu-make 3.81 3.82 developer/build/imake 1.0.4 1.0.5 developer/build/libtool 1.5.22 2.4.2 developer/build/makedepend 1.0.3 1.0.4 developer/documentation-tool/doxygen 1.5.7.1 1.7.6.1 developer/gnu-binutils 2.19 2.21.1 developer/java/jdepend not included 2.9 developer/java/jdk-6 1.6.0.26 1.6.0.35 developer/java/jdk-7 1.7.0.0 1.7.0.7 developer/java/jpackage-utils not included 1.7.5 developer/java/junit 4.5 4.10 developer/lexer/jflex not included 1.4.1 developer/parser/byaccj not included 1.14 developer/parser/java_cup not included 0.10 developer/quilt 0.47 0.60 developer/versioning/git 1.7.3.2 1.7.9.2 developer/versioning/mercurial 1.8.4 2.2.1 developer/versioning/subversion 1.6.16 1.7.5 diagnostic/constype 1.0.3 1.0.4 diagnostic/nmap 5.21 5.51 diagnostic/scanpci 0.12.1 0.13.1 diagnostic/wireshark 1.4.8 1.8.2 diagnostic/xload 1.1.0 1.1.1 editor/gnu-emacs 23.1 23.4 editor/vim 7.3.254 7.3.600 file/lndir 1.0.2 1.0.3 image/editor/bitmap 1.0.5 1.0.6 image/gnuplot 4.4.0 4.6.0 image/library/libexif 0.6.19 0.6.21 image/library/libpng 1.4.8 1.4.11 image/library/librsvg 2.26.3 2.34.1 image/xcursorgen 1.0.4 1.0.5 library/audio/pulseaudio not included 1.1 library/cacao 2.3.0.0 2.3.1.0 library/expat 2.0.1 2.1.0 library/gc 7.1 7.2 library/graphics/pixman 0.22.0 0.24.4 library/guile 1.8.4 1.8.6 library/java/javadb 10.5.3.0 10.6.2.1 library/java/subversion 1.6.16 1.7.5 library/json-c not included 0.9 library/libedit not included 3.0 library/libee not included 0.3.2 library/libestr not included 0.1.2 library/libevent 1.3.5 1.4.14.2 library/liblouis not included 2.1.1 library/liblouisxml not included 2.1.0 library/libtecla 1.6.0 1.6.1 library/libtool/libltdl 1.5.22 2.4.2 library/nspr 4.8.8 4.8.9 library/openldap 2.4.25 2.4.30 library/pcre 7.8 8.21 library/perl-5/subversion 1.6.16 1.7.5 library/python-2/jsonrpclib not included 0.1.3 library/python-2/lxml 2.1.2 2.3.3 library/python-2/nose not included 1.1.2 library/python-2/pyopenssl not included 0.11 library/python-2/subversion 1.6.16 1.7.5 library/python-2/tkinter-26 2.6.4 2.6.8 library/python-2/tkinter-27 2.7.1 2.7.3 library/security/nss 4.12.10 4.13.1 library/security/openssl 1.0.0.5 (1.0.0e) 1.0.0.10 (1.0.0j) mail/thunderbird 6.0 10.0.6 network/dns/bind 9.6.3.4.3 9.6.3.7.2 package/pkgbuild not included 1.3.104 print/filter/enscript not included 1.6.4 print/filter/gutenprint 5.2.4 5.2.7 print/lp/filter/foomatic-rip 3.0.2 4.0.15 runtime/java/jre-6 1.6.0.26 1.6.0.35 runtime/java/jre-7 1.7.0.0 1.7.0.7 runtime/perl-512 5.12.3 5.12.4 runtime/python-26 2.6.4 2.6.8 runtime/python-27 2.7.1 2.7.3 runtime/ruby-18 1.8.7.334 1.8.7.357 runtime/tcl-8/tcl-sqlite-3 3.7.6.3 3.7.11 security/compliance/openscap not included 0.8.1 security/nss-utilities 4.12.10 4.13.1 security/sudo 1.8.1.2 1.8.4.5 service/network/dhcp/isc-dhcp 4.1 4.1.0.6 service/network/dns/bind 9.6.3.4.3 9.6.3.7.2 service/network/ftp (ProFTPD) 1.3.3.0.5 1.3.3.0.7 service/network/samba 3.5.10 3.6.6 shell/conflict 0.2004.9.1 0.2010.6.27 shell/pipe-viewer 1.1.4 1.2.0 shell/zsh 4.3.12 4.3.17 system/boot/grub 0.97 1.99 system/font/truetype/liberation 1.4 1.7.2 system/library/freetype-2 2.4.6 2.4.9 system/library/libnet 1.1.2.1 1.1.5 system/management/cim/pegasus 2.9.1 2.11.0 system/management/ipmitool 1.8.10 1.8.11 system/management/wbem/wbemcli 1.3.7 1.3.9.1 system/network/routing/quagga 0.99.8 0.99.19 system/rsyslog not included 6.2.0 terminal/luit 1.1.0 1.1.1 text/convmv 1.14 1.15 text/gawk 3.1.5 3.1.8 text/gnu-grep 2.5.4 2.10 web/browser/firefox 6.0.2 10.0.6 web/browser/links 1.0 1.0.3 web/java-servlet/tomcat 6.0.33 6.0.35 web/php-53 not included 5.3.14 web/php-53/extension/php-apc not included 3.1.9 web/php-53/extension/php-idn not included 0.2.0 web/php-53/extension/php-memcache not included 3.0.6 web/php-53/extension/php-mysql not included 5.3.14 web/php-53/extension/php-pear not included 5.3.14 web/php-53/extension/php-suhosin not included 0.9.33 web/php-53/extension/php-tcpwrap not included 1.1.3 web/php-53/extension/php-xdebug not included 2.2.0 web/php-common not included 11.1 web/proxy/squid 3.1.8 3.1.18 web/server/apache-22 2.2.20 2.2.22 web/server/apache-22/module/apache-sed 2.2.20 2.2.22 web/server/apache-22/module/apache-wsgi not included 3.3 x11/diagnostic/xev 1.1.0 1.2.0 x11/diagnostic/xscope 1.3 1.3.1 x11/documentation/xorg-docs 1.6 1.7 x11/keyboard/xkbcomp 1.2.3 1.2.4 x11/library/libdmx 1.1.1 1.1.2 x11/library/libdrm 2.4.25 2.4.32 x11/library/libfontenc 1.1.0 1.1.1 x11/library/libfs 1.0.3 1.0.4 x11/library/libice 1.0.7 1.0.8 x11/library/libsm 1.2.0 1.2.1 x11/library/libx11 1.4.4 1.5.0 x11/library/libxau 1.0.6 1.0.7 x11/library/libxcb 1.7 1.8.1 x11/library/libxcursor 1.1.12 1.1.13 x11/library/libxdmcp 1.1.0 1.1.1 x11/library/libxext 1.3.0 1.3.1 x11/library/libxfixes 4.0.5 5.0 x11/library/libxfont 1.4.4 1.4.5 x11/library/libxft 2.2.0 2.3.1 x11/library/libxi 1.4.3 1.6.1 x11/library/libxinerama 1.1.1 1.1.2 x11/library/libxkbfile 1.0.7 1.0.8 x11/library/libxmu 1.1.0 1.1.1 x11/library/libxmuu 1.1.0 1.1.1 x11/library/libxpm 3.5.9 3.5.10 x11/library/libxrender 0.9.6 0.9.7 x11/library/libxres 1.0.5 1.0.6 x11/library/libxscrnsaver 1.2.1 1.2.2 x11/library/libxtst 1.2.0 1.2.1 x11/library/libxv 1.0.6 1.0.7 x11/library/libxvmc 1.0.6 1.0.7 x11/library/libxxf86vm 1.1.1 1.1.2 x11/library/mesa 7.10.2 7.11.2 x11/library/toolkit/libxaw7 1.0.9 1.0.11 x11/library/toolkit/libxt 1.0.9 1.1.3 x11/library/xtrans 1.2.6 1.2.7 x11/oclock 1.0.2 1.0.3 x11/server/xdmx 1.10.3 1.12.2 x11/server/xephyr 1.10.3 1.12.2 x11/server/xorg 1.10.3 1.12.2 x11/server/xorg/driver/xorg-input-keyboard 1.6.0 1.6.1 x11/server/xorg/driver/xorg-input-mouse 1.7.1 1.7.2 x11/server/xorg/driver/xorg-input-synaptics 1.4.1 1.6.2 x11/server/xorg/driver/xorg-input-vmmouse 12.7.0 12.8.0 x11/server/xorg/driver/xorg-video-ast 0.91.10 0.93.10 x11/server/xorg/driver/xorg-video-ati 6.14.1 6.14.4 x11/server/xorg/driver/xorg-video-cirrus 1.3.2 1.4.0 x11/server/xorg/driver/xorg-video-dummy 0.3.4 0.3.5 x11/server/xorg/driver/xorg-video-intel 2.10.0 2.18.0 x11/server/xorg/driver/xorg-video-mach64 6.9.0 6.9.1 x11/server/xorg/driver/xorg-video-mga 1.4.13 1.5.0 x11/server/xorg/driver/xorg-video-openchrome 0.2.904 0.2.905 x11/server/xorg/driver/xorg-video-r128 6.8.1 6.8.2 x11/server/xorg/driver/xorg-video-trident 1.3.4 1.3.5 x11/server/xorg/driver/xorg-video-vesa 2.3.0 2.3.1 x11/server/xorg/driver/xorg-video-vmware 11.0.3 12.0.2 x11/server/xserver-common 1.10.3 1.12.2 x11/server/xvfb 1.10.3 1.12.2 x11/server/xvnc 1.0.90 1.1.0 x11/session/sessreg 1.0.6 1.0.7 x11/session/xauth 1.0.6 1.0.7 x11/session/xinit 1.3.1 1.3.2 x11/transset 0.9.1 1.0.0 x11/trusted/trusted-xorg 1.10.3 1.12.2 x11/x11-window-dump 1.0.4 1.0.5 x11/xclipboard 1.1.1 1.1.2 x11/xclock 1.0.5 1.0.6 x11/xfd 1.1.0 1.1.1 x11/xfontsel 1.0.3 1.0.4 x11/xfs 1.1.1 1.1.2 P.S. To get the version numbers for this table, I ran a quick perl script over the output from: % pkg contents -H -r -t depend -a type=incorporate -o fmri \ `pkg contents -H -r -t depend -a type=incorporate -o fmri [email protected],5.11-0.175.1.0.0.24` \ | sort /tmp/11.1 % pkg contents -H -r -t depend -a type=incorporate -o fmri \ `pkg contents -H -r -t depend -a type=incorporate -o fmri [email protected],5.11-0.175.0.0.0.2` \ | sort /tmp/11.0

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• Songbird looping my library playlist

  - by Logi

  I'm using Songbird (on Windows) as my iTunes replacement. There's two things that annoy me about Songbird: 1) It has a web browser built in. I can ignore this as I don't use it. But, seriously, a web browser? :/ 2) It loops my library. This, I don't like. The way I play my audio is by launching Windows Explorer, navigating to my media library and double clicking on a single MP3. I only want to hear that one MP3. I don't use the Media Import function in Songbird - Or any other media player. But it insists on adding every song I play to the Library. Disabling this would be excellent but, falling short of that, I'd at least like to stop it repeating every song in the library. When Songbird finishes playing the last song in the Library (which is the song I just opened via Windows Explorer (gets appended to the library)), it jumps to the top of the library and starts playing all the songs again. How can I stop this? Songbird is set to 'Repeat none'

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• Improvements to Joshua Bloch's Builder Design Pattern?

  - by Jason Fotinatos

  Back in 2007, I read an article about Joshua Blochs take on the "builder pattern" and how it could be modified to improve the overuse of constructors and setters, especially when an object has a large number of properties, most of which are optional. A brief summary of this design pattern is articled here [http://rwhansen.blogspot.com/2007/07/theres-builder-pattern-that-joshua.html]. I liked the idea, and have been using it since. The problem with it, while it is very clean and nice to use from the client perspective, implementing it can be a pain in the bum! There are so many different places in the object where a single property is reference, and thus creating the object, and adding a new property takes a lot of time. So...I had an idea. First, an example object in Joshua Bloch's style: Josh Bloch Style: public class OptionsJoshBlochStyle { private final String option1; private final int option2; // ...other options here <<<< public String getOption1() { return option1; } public int getOption2() { return option2; } public static class Builder { private String option1; private int option2; // other options here <<<<< public Builder option1(String option1) { this.option1 = option1; return this; } public Builder option2(int option2) { this.option2 = option2; return this; } public OptionsJoshBlochStyle build() { return new OptionsJoshBlochStyle(this); } } private OptionsJoshBlochStyle(Builder builder) { this.option1 = builder.option1; this.option2 = builder.option2; // other options here <<<<<< } public static void main(String[] args) { OptionsJoshBlochStyle optionsVariation1 = new OptionsJoshBlochStyle.Builder().option1("firefox").option2(1).build(); OptionsJoshBlochStyle optionsVariation2 = new OptionsJoshBlochStyle.Builder().option1("chrome").option2(2).build(); } } Now my "improved" version: public class Options { // note that these are not final private String option1; private int option2; // ...other options here public String getOption1() { return option1; } public int getOption2() { return option2; } public static class Builder { private final Options options = new Options(); public Builder option1(String option1) { this.options.option1 = option1; return this; } public Builder option2(int option2) { this.options.option2 = option2; return this; } public Options build() { return options; } } private Options() { } public static void main(String[] args) { Options optionsVariation1 = new Options.Builder().option1("firefox").option2(1).build(); Options optionsVariation2 = new Options.Builder().option1("chrome").option2(2).build(); } } As you can see in my "improved version", there are 2 less places in which we need to add code about any addition properties (or options, in this case)! The only negative that I can see is that the instance variables of the outer class are not able to be final. But, the class is still immutable without this. Is there really any downside to this improvement in maintainability? There has to be a reason which he repeated the properties within the nested class that I'm not seeing?

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