Search Results

Search found 34141 results on 1366 pages for 'even mien'.

Page 150/1366 | < Previous Page | 146 147 148 149 150 151 152 153 154 155 156 157  | Next Page >

  • Achieving a Strong SEO Rating

    SEO or Search Engine Optimization is a must if you are serious in having your website placed with the search engine, and with great results. There are important guidelines to be followed. It is really not that hard to understand even for beginners. For beginners the term optimization may sound somewhat difficult, when actually it is very doable.

    Read the article

  • Configurable Objects - Introduction

    - by Anthony Shorten
    One of the interesting facilities in the framework is Configurable Object functionality (it is also known as Task Optimization and also known as Cool Tools). The idea is that any implementation can create their own views of the base product objects and services and implement functionality against those new views. For example, in Oracle Utilities Customer Care and Billing, there is a Person object. That object is used to store and manage information about individuals as well as companies. In the base product you would use the Person Maintenance screen and fill in some of the screen when you wanted to register or maintain and individual as well and fill out other parts of the screen when you wanted to register or maintain a company. This can be somewhat confusing to some customers. Using Configurable Objects this can be simplified. A business object can be created that is a view of the any object. For example, you could create a Human business object which would cover the aspects of the Person object pertaining to an individual and a Company business object to cover the aspects unique to a company. Even the tag names (i.e. Field Names) in the object can be changed to be more what the implementation is familiar with. The object can also restructure the object. For example, a common identifier for an individual in the USA is the Social Security number, this value is a Person Identifier (as this varies in each country). In the new Human object you can remap the Person Identifier as a Social Security number. To define a Business Object you use a schema editor built into the browser user interface and use a mapping language to setup the business objects. An example of the language is shown below in an extract of the schema for the Human business object. As you can see there are mapping as well as formatting and other tags. This information can be built manually or using a wizard which generates the base structure for you to alter. This is all stored as meta data when saved. Once a Business object is built it can be used as basis for code, other business objects (we support inheritance), called by a screen (called a UI Map) or even as a Web Service. This is just a start with Configurable Objects as you can also create views of base services called Business Services, Service Scripts used for non-object or complex object processing (as well as other things), UI Maps used for screens and Data Areas to reuse definitions across multiple objects. Configurable Objects are powerful and I only really touched on them here. Over the next few months I hope to add lots more entries about them.

    Read the article

  • Looking for mass cropping software

    - by Bart van Heukelom
    I'm looking for a tool than runs on Ubuntu that can let me: Open an image in a folder which has thousands Crop and rotate it Save as a copy, automatically named (not manually), with one click. Preferably with something in the name that I can later use to filter these cropped copies in Nautilus (unless it saves in another directory, that'd be even better). Move to next image and repeat Does it exist?

    Read the article

  • Diff annotation tool

    - by l0b0
    Among the 11 proven practices for more effective, efficient peer code review, diff annotation seems to be the one particularly well suited to tool assistance. The article is written by the architect of SmartBear's CodeCollaborator, so he of course recommends using that. Does anyone know of any alternatives? I can't think of anything that would be even close to paper+pen+marker in pure developer efficiency when it comes to explaining a piece of code.

    Read the article

  • Is ASP.NET MVC completely (and exclusively) based on conventions?

    - by Mike Valeriano
    --TL;DR Is there a "Hello World!" ASP.NET MVC tutorial out there that doesn't rely on conventions and "stock" projects? Is it even possible to take advantage of the technology without reusing the default file structure, and start from a single "hello_world.asp" file or something (like in PHP)? Am I completely mistaken and I should be looking somewhere else, maybe this? I'm interested in the MVC framework, not Web Forms --Background I've played a bit with PHP in the past, just for fun, and now I'm back to it since web development became relevant for me once again. I'm no professional, but I try to gain as much knowledge and control over the technology I'm working with as possible. I'm using Visual Studio 2012 for C# - my "desktop" language of choice - and since I got the Professional Edition from Dreamspark, the Web Development Tools are available, including ASP.NET MVC 4. I won't touch Web Forms, but the MVC Framework got my attention because the MVC pattern is something I can really relate to, since it provides the control I want but... not quite. Learning PHP was easy - and right form the start I could just create a "hello_world.php" file and just do something like this for immediate results: <!-- file: hello_world.php --> <?php> echo "Hello World!"; <?> But I couldn't find a single ASP.NET (MVC) tutorial out there (I'll be sure to buy one of the upcoming MVC 4 books, only a month away or so) that would start like that. They all start with a sample project, building up knowledge from the basics and heavily using conventions as they go along. Which is fine, I suppose, but it's now the best way for me to learn things. Even the "Empty" project template for a new ASP.NET MVC 4 Application in VS2012 is not empty at all: several files and folders are created for you - much like a new C# desktop application project, but with C# I can in fact start from scratch, creating the project structure myself. It is not the case with PHP: I can choose from a plethora of different MVC frameworks I can just create my own framework I can just skip frameworks altogether, and toss random PHP along with my HTML on a single file and make it work I understand the framework needs to establish some rules, but what if I just want to create a single page website with some C# logic behind it? Do I really need to create a whole bloat of files and folders for the sake of convention? Also, please understand that I haven't gotten far on any of those tutorials mainly because of this reason, but, if that's the only way to do it, I'll go for it using one of the books I've mentioned before. This is my first contact with ASP.NET but from the few comparisons I've read, I believe I should stay the hell away from Web Forms. Thank you. (Please forgive the broken English - it is not my primary language.)

    Read the article

  • Removing hard-coded values and defensive design vs YAGNI

    - by Ben Scott
    First a bit of background. I'm coding a lookup from Age - Rate. There are 7 age brackets so the lookup table is 3 columns (From|To|Rate) with 7 rows. The values rarely change - they are legislated rates (first and third columns) that have stayed the same for 3 years. I figured that the easiest way to store this table without hard-coding it is in the database in a global configuration table, as a single text value containing a CSV (so "65,69,0.05,70,74,0.06" is how the 65-69 and 70-74 tiers would be stored). Relatively easy to parse then use. Then I realised that to implement this I would have to create a new table, a repository to wrap around it, data layer tests for the repo, unit tests around the code that unflattens the CSV into the table, and tests around the lookup itself. The only benefit of all this work is avoiding hard-coding the lookup table. When talking to the users (who currently use the lookup table directly - by looking at a hard copy) the opinion is pretty much that "the rates never change." Obviously that isn't actually correct - the rates were only created three years ago and in the past things that "never change" have had a habit of changing - so for me to defensively program this I definitely shouldn't store the lookup table in the application. Except when I think YAGNI. The feature I am implementing doesn't specify that the rates will change. If the rates do change, they will still change so rarely that maintenance isn't even a consideration, and the feature isn't actually critical enough that anything would be affected if there was a delay between the rate change and the updated application. I've pretty much decided that nothing of value will be lost if I hard-code the lookup, and I'm not too concerned about my approach to this particular feature. My question is, as a professional have I properly justified that decision? Hard-coding values is bad design, but going to the trouble of removing the values from the application seems to violate the YAGNI principle. EDIT To clarify the question, I'm not concerned about the actual implementation. I'm concerned that I can either do a quick, bad thing, and justify it by saying YAGNI, or I can take a more defensive, high-effort approach, that even in the best case ultimately has low benefits. As a professional programmer does my decision to implement a design that I know is flawed simply come down to a cost/benefit analysis?

    Read the article

  • Monitor won't enter power save mode

    - by Adam Monsen
    My LCD monitor won't enter power save mode. I've gone into System ? Preferences ? Screensaver, clicked Power Management, then set Put display to sleep when inactive for: to 10 minutes (for both On AC Power and On Battery Power), but the monitor still doesn't enter power save mode, even after an hour. Anyone have ideas on what to try? I'm using Ubuntu 10.04.1 LTS 64-bit desktop on a Dell Latitude E6400 laptop.

    Read the article

  • How is precedence determined in C pointers?

    - by ankur.trapasiya
    I've come across two pointer declarations that I'm having trouble understanding. My understanding of precedence rules goes something like this: Operator Precedence Associativity (), [ ] 1 Left to Right *, identifier 2 Right to Left Data type 3 But even given this, I can't seem to figure out how to evaluate the following examples correctly: First example float * (* (*ptr)(int))(double **,char c) My evaluation: *(ptr) (int) *(*ptr)(int) *(*(*ptr)(int)) Then, double ** char c Second example unsigned **( * (*ptr) [5] ) (char const *,int *) *(ptr) [5] *(*ptr)[5] *(*(*ptr)[5]) **(*(*ptr)[5]) How should I read them?

    Read the article

  • Handy SQL Server Function Series: Part 1

    - by Most Valuable Yak (Rob Volk)
    I've been preparing to give a presentation on SQL Server for a while now, and a topic that was recommended was SQL Server functions.  More specifically, the lesser-known functions (like @@OPTIONS), and maybe some interesting ways to use well-known functions (like using PARSENAME to split IP addresses)  I think this is a veritable goldmine of useful information, and researching for the presentation has confirmed that beyond my initial expectations.I even found a few undocumented/underdocumented functions, so for the first official article in this series I thought I'd start with 2 of each, COLLATIONPROPERTY() and COLLATIONPROPERTYFROMID().COLLATIONPROPERTY() provides information about (wait for it) collations, SQL Server's method for handling foreign character sets, sort orders, and case- or accent-sensitivity when sorting character data.  The Books Online entry for  COLLATIONPROPERTY() lists 4 options for code page, locale ID, comparison style and version.  Used in conjunction with fn_helpcollations():SELECT *, COLLATIONPROPERTY(name,'LCID') LCID, COLLATIONPROPERTY(name,'CodePage') CodePage, COLLATIONPROPERTY(name,'ComparisonStyle') ComparisonStyle, COLLATIONPROPERTY(name,'Version') Version FROM fn_helpcollations()You can get some excellent information. (c'mon, be honest, did you even know about fn_helpcollations?)Collations in SQL Server have a unique name and ID, and you'll see one or both in various system tables or views like syscolumns, sys.columns, and INFORMATION_SCHEMA.COLUMNS.  Unfortunately they only link the ID and name for collations of existing columns, so if you wanted to know the collation ID of Albanian_CI_AI_WS, you'd have to declare a column with that collation and query the system table.While poking around the OBJECT_DEFINITION() of sys.columns I found a reference to COLLATIONPROPERTYFROMID(), and the unknown property "Name".  Not surprisingly, this is how sys.columns finds the name of the collation, based on the ID stored in the system tables.  (Check yourself if you don't believe me)Somewhat surprisingly, the "Name" property also works for COLLATIONPROPERTY(), although you'd already know the name at that point.  Some wild guesses and tests revealed that "CollationID" is also a valid property for both functions, so now:SELECT *, COLLATIONPROPERTY(name,'LCID') LCID, COLLATIONPROPERTY(name,'CodePage') CodePage, COLLATIONPROPERTY(name,'ComparisonStyle') ComparisonStyle, COLLATIONPROPERTY(name,'Version') Version, COLLATIONPROPERTY(name,'CollationID') CollationID FROM fn_helpcollations() Will get you the collation ID-name link you…probably didn't know or care about, but if you ever get on Jeopardy! and this question comes up, feel free to send some of your winnings my way. :)And last but not least, COLLATIONPROPERTYFROMID() uses the same properties as COLLATIONPROPERTY(), so you can use either one depending on which value you have available.Keep an eye out for Part 2!

    Read the article

  • New hidden parameters in Oracle 11.2

    - by Mike Dietrich
    We really welcome every external review of our slides. And also recommendations from customers visiting our workshops. So it happened to me more than a week ago that Marco Patzwahl, the owner of MuniqSoft GmbH, had a very lengthy train ride in Germany (as the engine drivers go on strike this week it could have become even worse) and nothing better to do then reviewing our slide set. And he had plenty of recommendations. Besides that he pointed us to something at least I was not aware of and added it to the slides: In patch set 11.2.0.2 a new behaviour for datafile write errors has been implemented. With this release ANY write error to a datafile will cause the instance to abort. Before 11.2.0.2 those errors usually led to an offline datafile if the database operates in archivelog mode (your production database do, don’t they?!) and the datafile does not belong to the SYSTEM tablespace. Internal discussion found this behaviour not up-to-date and alligned with RAC systems and modern storages. Therefore it has been changed and a new underscore parameter got introduced. _DATAFILE_WRITE_ERRORS_CRASH_INSTANCE=TRUE This is the default setting´and the new behaviour beginning with Oracle 11.2.0.2 If you would like to revert to the pre-11.2.0.2 behaviour you’ll have to set in your init.ora/spfile this parameter to false. But keep in mind that there’s a reason why this has been changed. You’ll find more info in MOS Note: 7691270.8 and this topic in the current version of the slides on slide 255. Thanks to Marco for the review!!   And then I received an email from Kurt Van Meerbeeck today. Kurt is pretty well known in the Oracle community. And he’s the owner of jDUL/DUDE, a database unloading tool which bypasses the Oracle database engine and access data direclty from the blocks. Kurt visited the upgrade workshop two weeks ago in Belgium and did highlight to me that since Oracle 11.2.0.1 even though you haven’t set neither SGA_TARGET nor MEMORY_TARGET the database might still do resize operations. Reason why this behaviour has been changed: Prevention of ORA-4031 errors. But on databases with extremly high loads this can cause trouble. Further information can be found in MOS Note:1269139.1 . And the parameter set to TRUE by default is called _MEMORY_IMM_MODE_WITHOUT_AUTOSGA=TRUE This can be found now in the slide set as well on slide number 240. And thanks to Kurt for this information!!

    Read the article

  • How To Easily Back Up Your Gmail and Perform Scheduled Backups With GMVault

    - by Chris Hoffman
    We all know backups are important, but we rarely think about backing up our email. GMVault can automatically back up your Gmail to your computer and even restore the emails to another Gmail account – convenient when switching Gmail addresses. We’ve also covered using Thunderbird to back up your web-based email account, but GMVault has a few advantages, including its integrated restore function and easy integration with the Windows Task Scheduler. 8 Deadly Commands You Should Never Run on Linux 14 Special Google Searches That Show Instant Answers How To Create a Customized Windows 7 Installation Disc With Integrated Updates

    Read the article

  • How to change color AND width of non overlay scrollbars in Ubuntu 12.04

    - by Chuqui
    I know many people have complained about the almost invisible and not usable scrollbars in recent versions of Ubuntu, even after removing or disabling the default overlay scrollbars. I wonder how can I easily change their color AND width. I have a 13.3 inches monitor with a 1600*900 resolution and I can barely see them, as you can see in these images: I already changed Firefox, LibreOffice and some other software's scrollbars using GNOME Color Chooser: By the way, I'm using Unity. Thanks!

    Read the article

  • BPM ADF Task forms. Checking whether the current user is in a BPM Swimlane

    - by Christopher Karl Chan
    @page { margin: 0.79in } P { margin-bottom: 0.08in } --Focus So this blog entry will focus on BPM Swimlane roles and users from a ADF context. So we have an ADF Task Details Form and we are in the process of making it richer and dynamic in functionality. A common requirement could be to dynamically show different areas based on the user logged into the workspace. Perhaps even we want to know even what swim-lane role the user belongs to. It is is a little bit harder to achieve then one thinks unless you know the trick. The Challenge The tricky part here is that the ADF Task Details Form is in fact part of a separate J2EE application to the main workspace. So if you try to use Java or Expression Language to get the logged in user you will only find anonymous and none of the BPM Roles you will be expecting. So what to do? The Magic First add the BC4J Security library to your view project. Then Restart JDeveloper. Now find the web.xml file in the view project of your ADF Task Details Application and look for the JpsFilter section. Then add in the following section. <init-param> <param-name>application.name</param-name> <param-value>OracleBPMProcessRolesApp</param-value></init-param> This will link your application to that of the BPM workspace. Then in your dynamic part of your ADF form you can now check whether the user logged into the BPM Workspace belongs in a BPM swim-lane in any BPM process. The best way to do this is by using expression language in the JSF page itself. Here I am simply changing the rendered flag to either true or false and thereby hiding or showing a section. Perhaps you are re-using the same form for a task in an approver swim-lane and ordinary user swimlane. So we only want the approver to see this field. So call the built in function to check if the user is a member of the BPM swim-lane role. The name of the role must be of the syntax BPMProject.RoleName <af:outputText value="This will only be rendered when the user is part of the BPM Swimlane Role rendered="#{securityContext.userInRole['BPMProjectName.Rolename']}"/> Now you must redeploy your ADF Task Form project Now (in the image above) the text will ONLY get rendered in the Task Details Form only if the user logged into the workspace is a member of the swimlane Unsecure of the BPM project SimpleTask

    Read the article

  • Using PHP version 5.2 or 5.3 for commercial products?

    - by Ash
    I'm doing research on what version of PHP to use when creating commercial scripts that will be sold to the public. Although the available stats aren't great, PHP 5.3 shows a 18.5% adoption rate. I'd like to use Symfony to create these scripts and it requires 5.3.2 which shows an even lower adoption rate (roughly 13% of that 18.5% use less than 5.3.2). Would I be risking much by jumping straight to PHP 5.3.2+ or should I ignore the stats and plough ahead?

    Read the article

  • To Serve Man?

    - by Dave Convery
    Since the announcement of Windows 8 and its 'Metro' interface, the .NET community has wondered if the skills they've spent so long developing might be swept aside,in favour of HTML5 and JavaScript. Mercifully, that only seems to be true of SilverLight (as Simon Cooper points out), but it did leave me thinking how easy it is to impose a technology upon people without directly serving their needs. Case in point: QR codes. Once, probably, benign in purpose, they seem to have become a marketer's tool for determining when someone has engaged with an advert in the real world, with the same certainty as is possible online. Nobody really wants to use QR codes - it's far too much hassle. But advertisers want that data - they want to know that someone actually read their billboard / poster / cereal box, and so this flawed technology is suddenly everywhere, providing little to no value to the people who are actually meant to use it. What about 3D cinema? Profits from the film industry have been steadily increasing throughout the period that digital piracy and mass sharing has been possible, yet the industry cinema chains have forced 3D films upon a broadly uninterested audience, as a way of providing more purpose to going to a cinema, rather than watching it at home. Despite advances in digital projection, 3D cinema is scarcely more immersive to us than were William Castle's hoary old tricks of skeletons on wires and buzzing chairs were to our grandparents. iTunes - originally just a piece of software that catalogued and ripped music for you, but which is now multi-purpose bloatware; a massive, system-hogging behemoth. If it was being built for the people that used it, it would have been split into three or more separate pieces of software long ago. But as bloatware, it serves Apple primarily rather than us, stuffed with Music, Video, Various stores and phone / iPad management all bolted into one. Why? It's because, that way, you're more likely to bump into something you want to buy. You can't even buy a new laptop without finding that a significant chunk of your hard drive has been sold to 'select partners' - advertisers, suppliers of virus-busting software, and endless bloatware-flogging pop-ups that make using a new laptop without reformatting the hard drive like stepping back in time. The product you want is not the one you paid for. This is without even looking at services like Facebook and Klout, who provide a notional service with the intention of slurping up as much data about you as possible (in Klout's case, whether you create an account with them or not). What technologies do you find annoying or intrusive, and who benefits from keeping them around?

    Read the article

  • fully encrypt website using SSL

    - by eddywebs
    I had been trying to use SSL for the following site http://bit.ly/e8Lj32 , although the SSL certificate is signed properly by networksolutions , each time the pages are loaded it still displays an SSl warning in browser warning "Some parts of the site are not using SSL" , in I.E, its even worst if you hit "no I dont want view unsecured part of the page" site does not display properly (as it blocks some of the widgets) screenshots upped at http://i.imgur.com/fm5GO.png

    Read the article

  • 10 Tips For Getting Your Business Domain Right

    In today?s connected world, having a website for your business can be more important than having a business card. Your website can even be critical enough to be the difference between business succes... [Author: Tanya Smith - Computers and Internet - March 31, 2010]

    Read the article

  • Slow Start For Passbook

    - by David Dorf
    Like many others, I pre-ordered my iPhone 5 then downloaded iOS 6 to my antiquated iPhone 4.  I decided the downgrade in mapping capabilities was worth access to Passbook, Apple's wallet of sorts that holds loyalty cards, tickets, and coupons.  To my disappointment, Passbook didn't work.  When it goes to the iTunes Store, it can't connect.  After a little research, I read that you can change the date on the iPhone to the future (I did March 2013), and then it will connect.  A list of apps that support Passbook are shown, some of which were already on my iPhone and others that required downloading.  Even when I put the date back on "automatic," things continued to work.  Not sure why. Anyway, even once I got into iTunes and made sure I had some of the apps downloaded, it wasn't clear what the next step was (gimme a break, its Friday afternoon).  Every time I opened Passbook, it sent me to the "Apps for Passbook" page on iTunes.  I tried downloading one of the suggested apps that I didn't already have (Walgreens).  The app's icon has a "new" stripe across the icon.  I launched it and it said it had Passbook integration. So I needed to login or signup with the loyalty program.  After figuring out what my username and password already was, it then offered to add the loyalty card to Passbook, which I accepted.  Now when I flip over to Passbook, I can see the loyalty card there.  I guess I need to go into each app to "push" cards into Passbook. People seem to be using it.  Twenty-four hours after iOS 6 was released, Sephora had 20,000 users of Passbook. Starbucks says they'll be integrated to Passbook by the end of the month, and Target is already offering coupons via Passbook.  After a few more retailers get on board, Apple may not need to consider NFC.

    Read the article

  • 9/18 Live Webcast: Three Compelling Reasons to Upgrade to Oracle Database 11g - Still time to register

    - by jgelhaus
    If you or your organization is still working with Oracle Database 10g or an even older version, now is the time to upgrade. Oracle Database 11g offers a wide variety of advantages to enhance your operation. Join us 10 am PT / 1pm ET September 18th for this live Webcast and learn about what you’re missing: the business, operational, and technical benefits. With Oracle Database 11g, you can: Upgrade with zero downtime Improve application performance and database security Reduce the amount of storage required Save time and money Register today 

    Read the article

  • HTG Explains: What Are the Sys Rq, Scroll Lock, and Pause/Break Keys on My Keyboard?

    - by Chris Hoffman
    Glance at your keyboard and chances are you’ll see a few keys you never use near the top-right corner – Sys Rq, Scroll Lock, and Pause / Break. Have you ever wondered what those keys are for? While these keys have been removed from some computer keyboards today, they’re still a common sight — even on new keyboards. Image Credit: ajmexico on Flickr 8 Deadly Commands You Should Never Run on Linux 14 Special Google Searches That Show Instant Answers How To Create a Customized Windows 7 Installation Disc With Integrated Updates

    Read the article

  • How important is knowing functionality before coding?

    - by minusSeven
    I work for a software development company where the development work have been off shored to us. The on shore team handle the support and talk directly to the clients. We never talk to the clients directly we just talk people from the on shore team who talk directly to the clients. When requirements come, on shore team talk to the clients and make requirement documents and informs us. We make design documents after studying the requirements (we follow traditional waterfall model ). But there is one problem in the whole process: nobody in the either off-shore or on-shore understand the functionality of the application completely. We just know its a big complex web app handling complex order processing, catalog management, campaign management and other activities. We struggle with the design document as the requirements would not be clear. It then goes into a series of questions/answers back and forth between the on shore team,off shore team and clients. We would often be told to understand functionality from the code. But that's usually not feasible as the code base is huge and even understanding a simple menu item take days if not weeks. We tried telling the clients to give us knowledge transfer about the application but to no avail. Our manager would often tell us to start coding even if the design document is not complete or requirements not clear. We would start by coding part of the requirement that seems clear and wait for the rest. This usually would delay the deployment by a month. In extreme cases we would have very low errors in the development and production but the clients would say that's not what they asked. That would start a blame game and a series of change requests and we would end up developing something very different. My question is how would you do development work if you don't know the functionality of the app fully? UPDATE About development methodology it isn't really my choice and I am not my team's lead It is the way it began. I tried to tell people about the advantages of agile but to no avail. Besides I don't think my team has the necessary mindset to work in AGILE environment.

    Read the article

  • Ideal programming language learning sequence?

    - by Gulshan
    What do you think? What is the ideal programming language learning sequence which will cover most of the heavily used languages and paradigms today as well as help to grasp common programming basics, ideas and practices? You can even suggest learning sequence for paradigms rather than languages. N.B. : This is port of the question I asked in stackoverflow and was closed for being subjective and argumentative.

    Read the article

  • The Fast Guide to Application Profiling

    In this sample chapter from his recently released book (co-Authored with Paul Glavich) Chris Farrell gives us a fast overview of performance profiling, memory profiling, profiling tools, and in fact everything we need to know when it comes to profiling our applications. This is a great first step, and The Complete Guide to .NET Performance Testing and Optimization is crammed with even more indispensable knowledge.

    Read the article

  • Is there a language or design pattern that allows the *removal* of object behavior or properties in a class hierarchy?

    - by Sebastien Diot
    A well-know shortcoming of traditional class hierarchies is that they are bad when it comes to model the real world. As an example, trying to represent animals species with classes. There are actually several problems when doing that, but one that I never saw a solution to is when a sub-class "looses" a behavior or properties that was defined in a super-class, like a penguin not being able to fly (there are probably better examples, but that's the first one that comes to my mind, having seen "Madagascar 2" recently). On the one hand, you don't want to define for every property and behavior some flag that specifies if it is at all present, and check it every time before accessing that behavior or property. You would just like to say that birds can fly, simply and clearly, in the Bird class. But then it would be nice if one could define "exceptions" afterward, without having to use some horrible hacks everywhere. This often happens when a system has been productive for a while. You suddenly find an "exception" that doesn't fit in the original design at all, and you don't want to change a large portion of your code to accommodate it. So, is there some language or design patterns that can cleanly handle this problem, without requiring major changes to the "super-class", and all the code that uses it? Even if a solution only handle a specific case, several solutions might together form a complete strategy. [EDIT] Forgot about the Liskov Substitution Principle. That is why you can't do it. Assuming you define "traits/interfaces" for all major "feature groups", you can freely implement traits in different branches of the hierarchy, like the Flying trait could be implemented by Birds, and some special kind of squirrels and fish. So my question could amount to "How could I un-implement a trait?" If your super-class is a Java Serializable, you have to be one too, even if there is no way for you to serialize your state, for example if you contained a "Socket". So one way to do it is to always define all your traits in pair from the start: Flying and NotFlying (which would throw UnsupportedOperationExceiption, if not checked against). The Not-trait would not define any new interface, and could be simply checked for. Sounds like a "cheap" solution, in particular if used from the start.

    Read the article

< Previous Page | 146 147 148 149 150 151 152 153 154 155 156 157  | Next Page >