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• What modern design pattern / software engineering books for Java SE 6 do you recommend ?

  - by Scott Davies

  Hi, I am very familiar with Java 6 SE language features and am now looking for modern books that cover design patterns in Java for beginners as well as software engineering books that discuss architectures, algorithms and best practices in Java coding (sort of like the Effective C# books). I am aware of the classic GoF design patterns book, however, I'd like a more modern reference that takes advantage of the features of Java 6 SE. What books would you recommend ? Thanks, Scott

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• The Evolution Of C#

  - by Paulo Morgado

  The first release of C# (C# 1.0) was all about building a new language for managed code that appealed, mostly, to C++ and Java programmers. The second release (C# 2.0) was mostly about adding what wasn’t time to built into the 1.0 release. The main feature for this release was Generics. The third release (C# 3.0) was all about reducing the impedance mismatch between general purpose programming languages and databases. To achieve this goal, several functional programming features were added to the language and LINQ was born. Going forward, new trends are showing up in the industry and modern programming languages need to be more: Declarative With imperative languages, although having the eye on the what, programs need to focus on the how. This leads to over specification of the solution to the problem in hand, making next to impossible to the execution engine to be smart about the execution of the program and optimize it to run it more efficiently (given the hardware available, for example). Declarative languages, on the other hand, focus only on the what and leave the how to the execution engine. LINQ made C# more declarative by using higher level constructs like orderby and group by that give the execution engine a much better chance of optimizing the execution (by parallelizing it, for example). Concurrent Concurrency is hard and needs to be thought about and it’s very hard to shoehorn it into a programming language. Parallel.For (from the parallel extensions) looks like a parallel for because enough expressiveness has been built into C# 3.0 to allow this without having to commit to specific language syntax. Dynamic There was been lots of debate on which ones are the better programming languages: static or dynamic. The fact is that both have good qualities and users of both types of languages want to have it all. All these trends require a paradigm switch. C# is, in many ways, already a multi-paradigm language. It’s still very object oriented (class oriented as some might say) but it can be argued that C# 3.0 has become a functional programming language because it has all the cornerstones of what a functional programming language needs. Moving forward, will have even more. Besides the influence of these trends, there was a decision of co-evolution of the C# and Visual Basic programming languages. Since its inception, there was been some effort to position C# and Visual Basic against each other and to try to explain what should be done with each language or what kind of programmers use one or the other. Each language should be chosen based on the past experience and familiarity of the developer/team/project/company and not by particular features. In the past, every time a feature was added to one language, the users of the other wanted that feature too. Going forward, when a feature is added to one language, the other will work hard to add the same feature. This doesn’t mean that XML literals will be added to C# (because almost the same can be achieved with LINQ To XML), but Visual Basic will have auto-implemented properties. Most of these features require or are built on top of features of the .NET Framework and, the focus for C# 4.0 was on dynamic programming. Not just dynamic types but being able to talk with anything that isn’t a .NET class. Also introduced in C# 4.0 is co-variance and contra-variance for generic interfaces and delegates. Stay tuned for more on the new C# 4.0 features.

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• Software Architecture verses Software Design

  Recently, I was asked what the differences between software architecture and software design are. At a very superficial level both architecture and design seem to mean relatively the same thing. However, if we examine both of these terms further we will find that they are in fact very different due to the level of details they encompass. Software Architecture can be defined as the essence of an application because it deals with high level concepts that do not include any details as to how they will be implemented. To me this gives stakeholders a view of a system or application as if someone was viewing the earth from outer space. At this distance only very basic elements of the earth can be detected like land, weather and water. As the viewer comes closer to earth the details in this view start to become more defined. Details about the earth’s surface will start to actually take form as well as mane made structures will be detected. The process of transitioning a view from outer space to inside our earth’s atmosphere is similar to how an architectural concept is transformed to an architectural design. From this vantage point stakeholders can start to see buildings and other structures as if they were looking out of a small plane window. This distance is still high enough to see a large area of the earth’s surface while still being able to see some details about the surface. This viewing point is very similar to the actual design process of an application in that it takes the very high level architectural concept or concepts and applies concrete design details to form a software design that encompasses the actual implementation details in the form of responsibilities and functions. Examples of these details include: interfaces, components, data, and connections. In review, software architecture deals with high level concepts without regard to any implementation details. Software design on the other hand takes high level concepts and applies concrete details so that software can be implemented. As part of the transition between software architecture to the creation of software design an evaluation on the architecture is recommended. There are several benefits to including this step as part of the transition process. It allows for projects to ensure that they are on the correct path as to meeting the stakeholder’s requirement goals, identifies possible cost savings and can be used to find missing or nonspecific requirements that cause ambiguity in a design. In the book “Evaluating Software Architectures: Methods and Case Studies”, they define key benefits to adding an architectural review process to ensure that an architecture is ready to move on to the design phase. Benefits to evaluating software architecture: Gathers all stakeholders to communicate about the project Goals are clearly defined in regards to the creation or validation of specific requirements Goals are prioritized so that when conflicts occur decisions will be made based on goal priority Defines a clear expectation of the architecture so that all stakeholders have a keen understanding of the project Ensures high quality documentation of the architecture Enables discoveries of architectural reuse  Increases the quality of architecture practices. I can remember a few projects that I worked on that could have really used an architectural review prior to being passed on to developers. This project was to create some new advertising space on the company’s website in order to sell space based on the location and some other criteria. I was one of the developer selected to lead this project and I was given a high level design concept and a long list of ever changing requirements due to the fact that sales department had no clear direction as to what exactly the project was going to do or how they were going to bill the clients once they actually agreed to purchase the Ad space. In my personal opinion IT should have pushed back to have the requirements further articulated instead of forcing programmers to code blindly attempting to build such an ambiguous project.  Unfortunately, we had to suffer with this project for about 4 months when it should have only taken 1.5 to complete due to the constantly changing and unclear requirements. References  Clements, P., Kazman, R., & Klein, M. (2002). Evaluating Software Architectures. Westford, Massachusetts: Courier Westford. 

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• The Evolution of Television and Home Entertainment

  - by Bill Evjen

  This is a group that is focused on entertainment in the aviation industry. I am attending their conference for the first time as it relates to my job at Swank Motion Pictures and what we do for our various markets. I will post my notes here. The Evolution of Television and Home Entertainment by Patrick Cosson, Veebeam TV has been the center of living rooms for sometime. Conversations and culture evolve around the TV. The way we consume this content has dramatically been changing. After TV, we had the MTV revolution of TV. It has created shorter attention spans, it made us more materialistic, narcissistic, and not easily impressed. Then we came to the Internet. The amount of content has expanded. It contains a ton of user-generated content, provides filtering, organization, distribution. We now have a problem. We are in the age of digital excess. We can access whatever we want. In conjunction with this – we are moving. The challenge we have now is curation. The trends  we see: rapid shift from scheduled to on demand consumption. A move to Internet protocols from cable Rapid fragmentation of media a transition from the TV set to a variety of screens Social connections bring mediators and amplifiers. TiVo – the shift to on demand It is because of a time-crunch Provides personal experiences Once old consumption habits are changed, there is no way back! Experiences are that people are loading up content and then bringing it with them on planes, to hotels, etc. Rapid fragmentation of media sources Many new professional content sources and channels, the rise of digital distribution, and the rise of user-generated content contribute to the wealth of content sources and abundant choice. Netflix, BBC iPlayer, hulu, Pandora, iTunes, Amazon Video, Vudu, Voddler, Spotify (these companies didn’t exist 5 years ago). People now expect this kind of consumption. People are now thinking how to deliver all these tools. Transition from the TV set to multi-screens The TV screen has traditionally been the dominant consumption screen for TV and video. Now the PC, game consoles, and various mobile devices are rapidly becoming common video devices. Multi-screens are now the norm. Social connections becoming key mediators What increasingly funnels traffic on the web, social networking enablers, will become an integral part of the discovery, consumption and sharing model for Television. The revolution will be broadcasted on Facebook and Twitter. There is business disruption There are a lot of new entrants Rapid internationalization Increasing competition from existing media players A fragmenting audience base Web browser Freedom to access any site The fight over the walled garden Most devices are not powerful enough to support a full browser PC will always be present in the living room Wireless link between PC and TV Output 1080p, plays anything, secure Key players and their challenges Services Internet media is increasingly interconnected to social media and publicly shared UGC Content delivery moving to IPTV Rights management issues are creating silos and hindering a great user experience and growth Devices Devices are becoming people’s windows into all kinds of media from all kinds of sources There won’t be a consolidation of the device landscape, rather the opposite Finding the right niche makes the most sense. We are moving to an on demand world of streaming world. People want full access to anything.

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• What design pattern shall I use in this question?

  - by iyad al aqel

  To be frank, this is a homework question, so I'll tell you my opinion. Can you let me know my mistakes rather than giving me the solution? This is the question : Assume a restaurant that only offers the following two types of meals: (a) a full meal and (b)an economic meal. The full meal consists of the following food items and is served in the following order: 1. Appetizer 2. Drink 3. Main dish 4. Dessert Meanwhile the economic meal consists of the following food items and is served in the following order: 1. Drink 2. Main dish Identify the most appropriate design pattern that can be used to allow a customer to only order using one of the two types of meals provided and that the meal components must be served in the given order. I'm confused between the Factory and the Iterator and using them both together. Using the factory Pattern we can create the two meals full and economic and provide the user with with a base object class that will decide upon. But how can we enforce the ordering of the elements, I thought of using the iterator along that will iterate through the the composite of the two created factories sort of speak. What do you think?

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• Big Data – Evolution of Big Data – Day 3 of 21

  - by Pinal Dave

  In yesterday’s blog post we answered what is the Big Data. Today we will understand why and how the evolution of Big Data has happened. Though the answer is very simple, I would like to tell it in the form of a history lesson. Data in Flat File In earlier days data was stored in the flat file and there was no structure in the flat file.  If any data has to be retrieved from the flat file it was a project by itself. There was no possibility of retrieving the data efficiently and data integrity has been just a term discussed without any modeling or structure around. Database residing in the flat file had more issues than we would like to discuss in today’s world. It was more like a nightmare when there was any data processing involved in the application. Though, applications developed at that time were also not that advanced the need of the data was always there and there was always need of proper data management. Edgar F Codd and 12 Rules Edgar Frank Codd was a British computer scientist who, while working for IBM, invented the relational model for database management, the theoretical basis for relational databases. He presented 12 rules for the Relational Database and suddenly the chaotic world of the database seems to see discipline in the rules. Relational Database was a promising land for all the unstructured database users. Relational Database brought into the relationship between data as well improved the performance of the data retrieval. Database world had immediately seen a major transformation and every single vendors and database users suddenly started to adopt the relational database models. Relational Database Management Systems Since Edgar F Codd proposed 12 rules for the RBDMS there were many different vendors who started them to build applications and tools to support the relationship between database. This was indeed a learning curve for many of the developer who had never worked before with the modeling of the database. However, as time passed by pretty much everybody accepted the relationship of the database and started to evolve product which performs its best with the boundaries of the RDBMS concepts. This was the best era for the databases and it gave the world extreme experts as well as some of the best products. The Entity Relationship model was also evolved at the same time. In software engineering, an Entity–relationship model (ER model) is a data model for describing a database in an abstract way. Enormous Data Growth Well, everything was going fine with the RDBMS in the database world. As there were no major challenges the adoption of the RDBMS applications and tools was pretty much universal. There was a race at times to make the developer’s life much easier with the RDBMS management tools. Due to the extreme popularity and easy to use system pretty much every data was stored in the RDBMS system. New age applications were built and social media took the world by the storm. Every organizations was feeling pressure to provide the best experience for their users based the data they had with them. While this was all going on at the same time data was growing pretty much every organization and application. Data Warehousing The enormous data growth now presented a big challenge for the organizations who wanted to build intelligent systems based on the data and provide near real time superior user experience to their customers. Various organizations immediately start building data warehousing solutions where the data was stored and processed. The trend of the business intelligence becomes the need of everyday. Data was received from the transaction system and overnight was processed to build intelligent reports from it. Though this is a great solution it has its own set of challenges. The relational database model and data warehousing concepts are all built with keeping traditional relational database modeling in the mind and it still has many challenges when unstructured data was present. Interesting Challenge Every organization had expertise to manage structured data but the world had already changed to unstructured data. There was intelligence in the videos, photos, SMS, text, social media messages and various other data sources. All of these needed to now bring to a single platform and build a uniform system which does what businesses need. The way we do business has also been changed. There was a time when user only got the features what technology supported, however, now users ask for the feature and technology is built to support the same. The need of the real time intelligence from the fast paced data flow is now becoming a necessity. Large amount (Volume) of difference (Variety) of high speed data (Velocity) is the properties of the data. The traditional database system has limits to resolve the challenges this new kind of the data presents. Hence the need of the Big Data Science. We need innovation in how we handle and manage data. We need creative ways to capture data and present to users. Big Data is Reality! Tomorrow In tomorrow’s blog post we will try to answer discuss Basics of Big Data Architecture. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• Adobe InDesign templates and design templates' cross-compatibility

  - by hinghoo

  Do Adobe InDesign templates only work in InDesign? What are the options for design template formats, and what programs do they work in?

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• Evolution of mainstream programming languages: simplicity versus complexity.

  - by Giorgio

  I had posted this question on http://stackoverflow.com but I was suggested that it may be more appropriate to post it on this forum. I did a quick search on this site and it seems to me that this question has not been asked yet. Please give me a hint if the topic has been raised already by someone else. Update I have rephrased this question, removed personal opinions and made it shorter. I hope in this way it is better suited for this forum. By looking at the recent development of Java (Java 7) and C++ (C++0x) I see that new features are added to these languages. For sure this makes it easier to use certain programming idioms, adding to the productivity of developers. On the other hand, there might be the following risks A language becomes too big, complex, and difficult to understand. It lacks coherence in the design, e.g. if it mixes different paradigms like object-orientation and functional programming, which might not fit well together. Questions: what is more important to you as a developer: to have a rich language that captures a large collection of programming idioms or to have a small language that aims at coherence and simplicity (of course, with a good deal of libraries and tools accompanying it)? Or is it possible to have both? With respect to these issues: How do you judge the current evolutions of main-stream programming languages like Java or C++? Are they becoming too complex, less intuitive? Do they have enough features? Do they need more? Are they still easy enough to understand and use?

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• The Evolution of Computer Keyboards

  - by Jason Fitzpatrick

  While the basic shape of keyboards has remained largely unchanged over the last thirty years, the guts have undergone several transformations. Read on to explore the history of the computer keyboard. ComputerWorld delves into the history of the modern keyboard, including the heavy influence IBM’s extensive keyboard research on early keyboards: As far as direct influences on the modern computer keyboard, IBM’s Selectric typewriter was one of the biggest. IBM released the first model of its iconic electromechanical typewriter in 1961, a time when being able to type fast and accurately was a highly sought-after skill. Dag Spicer, senior curator at the Computer History Museum, notes that as the Selectric models rose to prominence, admins grew to love the feel of the keyboard because of IBM’s dogged focus on making the ergonomics comfortable. “IBM’s probably done more than anyone to find [keyboard] ergonomics that work for everyone,” Spicer says. So when the PC hit the scene a decade or two later, the Selectric was largely viewed as the baseline to design keyboards for those newfangled computers you could put in your office or home. Hit up the link below to continue reading about how the Selectric influenced keyboards throughout the 1980s and what replaced the crisp clacking of early IBM-styled models. 6 Ways Windows 8 Is More Secure Than Windows 7 HTG Explains: Why It’s Good That Your Computer’s RAM Is Full 10 Awesome Improvements For Desktop Users in Windows 8

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• Rapid Evolution of Society & Technology

  - by Michael Snow

  We caught up with Brian Solis on the phone the other day and Christie Flanagan had a chance to chat with him and learn a bit more about him and some of the concepts he'll be addressing in our Social Business Thought Leaders Webcast on Thursday 12/13/12. «--- Interview with Brian Solis  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-family:"Calibri","sans-serif"; mso-ascii- mso-ascii-theme-font:minor-latin; mso-fareast- mso-fareast-theme-font:minor-latin; mso-hansi- mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Be sure and register for this week's webcast ---» ------------------- Guest post by Brian Solis. Reposted (Borrowed) from his posting of May 24, 2012 Dear [insert business name], what’s your promise? - Brian Solis You say you want to get closer to customers, but your actions are different than your words. You say you want to “surprise and delight” customers, but your product development teams are too busy building against a roadmap without consideration of the 5th P of marketing…people. Your employees are your number one asset, however the infrastructure of the organization has turned once optimistic and ambitious intrapreneurs into complacent cogs or worse, your greatest detractors. You question the adoption of disruptive technology by your internal champions yet you’ve not tried to find the value for yourself. You’re a change agent and you truly wish to bring about change, but you’ve not invested time or resources to answer “why” in your endeavors to become a connected or social business. If we are to truly change, we must find purpose. We must uncover the essence of our business and the value it delivers to traditional and connected consumers. We must rethink the spirit of today’s embrace and clearly articulate how transformation is going to improve customer and employee experiences and relationships now and over time. Without doing so, any attempts at evolution will be thwarted by reality. In an era of Digital Darwinism, no business is too big to fail or too small to succeed. These are undisciplined times which require alternative approaches to recognize and pursue new opportunities. But everything begins with acknowledging the 360 view of the world that you see today is actually a filtered view of managed and efficient convenience. Today, many organizations that were once inspired by innovation and engagement have fallen into a process of marketing, operationalizing, managing, and optimizing. That might have worked for the better part of the last century, but for the next 10 years and beyond, new vision, leadership and supporting business models will be written to move businesses from rigid frameworks to adaptive and agile entities. I believe that today’s executives will undergo a great test; a test of character, vision, intention, and universal leadership. It starts with a simple, but essential question…what is your promise? Notice, I didn’t ask about your brand promise. Nor did I ask for you to cite your mission and vision statements. This is much more than value propositions or manufactured marketing language designed to hook audiences and stakeholders. I asked for your promise to me as your consumer, stakeholder, and partner. This isn’t about B2B or B2C, but instead, people to people, person to person. It is this promise that will breathe new life into an organization that on the outside, could be misdiagnosed as catatonic by those who are disrupting your markets. A promise, for example, is meant to inspire. It creates alignment. It serves as the foundation for your vision, mission, and all business strategies and it must come from the top to mean anything. For without it, we cannot genuinely voice what it is we stand for or stand behind. Think for a moment about the definition of community. It’s easy to confuse a workplace or a market where everyone simply shares common characteristics. However, a community in this day and age is much more than belonging to something, it’s about doing something together that makes belonging matter The next few years will force a divide where companies are separated by intention as measured by actions and words. But, becoming a social business is not enough. Becoming more authentic and transparent doesn’t serve as a mantra for a renaissance. A promise is the ink that inscribes the spirit of the relationship between you and me. A promise serves as the words that influence change from within and change beyond the halls of our business. It is the foundation for a renewed embrace, one that must then find its way to every aspect of the organization. It’s the difference between a social business and an adaptive business. While an adaptive business can also be social, it is the culture of the organization that strives to not just use technology to extend current philosophies or processes into new domains, but instead give rise to a new culture where striving for relevance is among its goals. The tools and networks simply become enablers of a greater mission You are reading this because you believe in something more than what you’re doing today. While you fight for change within your organization, remember to aim for a higher purpose. Organizations that strive for innovation, imagination, and relevance will outperform those that do not. Part of your job is to lead a missionary push that unites the groundswell with a top down cascade. Change will only happen because you and other internal champions see what others can’t and will do what other won’t. It takes resolve. It takes the ability to translate new opportunities into business value. And, it takes courage. “This is a very noisy world, so we have to be very clear what we want them to know about us”-Steve Jobs ----------------------------------------------------------------- So -- where do you begin to evaluate the kind of experience you are delivering for your customers, partners, and employees?  Take a look at this White Paper: Creating a Successful and Meaningful Customer Experience on the Web and then have a cup of coffee while you listen to the sage advice of Guy Kawasaki in a short video below.   An interview with Guy Kawasaki on Maximizing Social Media Channels 

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• .NET Code Evolution

  - by Alois Kraus

  Originally posted on: http://geekswithblogs.net/akraus1/archive/2013/07/24/153504.aspxAt my day job I do look at a lot of code written by other people. Most of the code is quite good and some is even a masterpiece. And there is also code which makes you think WTF… oh it was written by me. Hm not so bad after all. There are many excuses reasons for bad code. Most often it is time pressure followed by not enough ambition (who cares) or insufficient training. Normally I do care about code quality quite a lot which makes me a (perceived) slow worker who does write many tests and refines the code quite a lot because of the design deficiencies. Most of the deficiencies I do find by putting my design under stress while checking for invariants. It does also help a lot to step into the code with a debugger (sometimes also Windbg). I do this much more often when my tests are red. That way I do get a much better understanding what my code really does and not what I think it should be doing. This time I do want to show you how code can evolve over the years with different .NET Framework versions. Once there was  time where .NET 1.1 was new and many C++ programmers did switch over to get rid of not initialized pointers and memory leaks. There were also nice new data structures available such as the Hashtable which is fast lookup table with O(1) time complexity. All was good and much code was written since then. At 2005 a new version of the .NET Framework did arrive which did bring many new things like generics and new data structures. The “old” fashioned way of Hashtable were coming to an end and everyone used the new Dictionary<xx,xx> type instead which was type safe and faster because the object to type conversion (aka boxing) was no longer necessary. I think 95% of all Hashtables and dictionaries use string as key. Often it is convenient to ignore casing to make it easy to look up values which the user did enter. An often followed route is to convert the string to upper case before putting it into the Hashtable. Hashtable Table = new Hashtable(); void Add(string key, string value) { Table.Add(key.ToUpper(), value); } This is valid and working code but it has problems. First we can pass to the Hashtable a custom IEqualityComparer to do the string matching case insensitive. Second we can switch over to the now also old Dictionary type to become a little faster and we can keep the the original keys (not upper cased) in the dictionary. Dictionary<string, string> DictTable = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase); void AddDict(string key, string value) { DictTable.Add(key, value); } Many people do not user the other ctors of Dictionary because they do shy away from the overhead of writing their own comparer. They do not know that .NET has for strings already predefined comparers at hand which you can directly use. Today in the many core area we do use threads all over the place. Sometimes things break in subtle ways but most of the time it is sufficient to place a lock around the offender. Threading has become so mainstream that it may sound weird that in the year 2000 some guy got a huge incentive for the idea to reduce the time to process calibration data from 12 hours to 6 hours by using two threads on a dual core machine. Threading does make it easy to become faster at the expense of correctness. Correct and scalable multithreading can be arbitrarily hard to achieve depending on the problem you are trying to solve. Lets suppose we want to process millions of items with two threads and count the processed items processed by all threads. A typical beginners code might look like this: int Counter; void IJustLearnedToUseThreads() { var t1 = new Thread(ThreadWorkMethod); t1.Start(); var t2 = new Thread(ThreadWorkMethod); t2.Start(); t1.Join(); t2.Join(); if (Counter != 2 * Increments) throw new Exception("Hmm " + Counter + " != " + 2 * Increments); } const int Increments = 10 * 1000 * 1000; void ThreadWorkMethod() { for (int i = 0; i < Increments; i++) { Counter++; } } It does throw an exception with the message e.g. “Hmm 10.222.287 != 20.000.000” and does never finish. The code does fail because the assumption that Counter++ is an atomic operation is wrong. The ++ operator is just a shortcut for Counter = Counter + 1 This does involve reading the counter from a memory location into the CPU, incrementing value on the CPU and writing the new value back to the memory location. When we do look at the generated assembly code we will see only inc dword ptr [ecx+10h] which is only one instruction. Yes it is one instruction but it is not atomic. All modern CPUs have several layers of caches (L1,L2,L3) which try to hide the fact how slow actual main memory accesses are. Since cache is just another word for redundant copy it can happen that one CPU does read a value from main memory into the cache, modifies it and write it back to the main memory. The problem is that at least the L1 cache is not shared between CPUs so it can happen that one CPU does make changes to values which did change in meantime in the main memory. From the exception you can see we did increment the value 20 million times but half of the changes were lost because we did overwrite the already changed value from the other thread. This is a very common case and people do learn to protect their  data with proper locking.   void Intermediate() { var time = Stopwatch.StartNew(); Action acc = ThreadWorkMethod_Intermediate; var ar1 = acc.BeginInvoke(null, null); var ar2 = acc.BeginInvoke(null, null); ar1.AsyncWaitHandle.WaitOne(); ar2.AsyncWaitHandle.WaitOne(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Intermediate did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Intermediate() { for (int i = 0; i < Increments; i++) { lock (this) { Counter++; } } } This is better and does use the .NET Threadpool to get rid of manual thread management. It does give the expected result but it can result in deadlocks because you do lock on this. This is in general a bad idea since it can lead to deadlocks when other threads use your class instance as lock object. It is therefore recommended to create a private object as lock object to ensure that nobody else can lock your lock object. When you read more about threading you will read about lock free algorithms. They are nice and can improve performance quite a lot but you need to pay close attention to the CLR memory model. It does make quite weak guarantees in general but it can still work because your CPU architecture does give you more invariants than the CLR memory model. For a simple counter there is an easy lock free alternative present with the Interlocked class in .NET. As a general rule you should not try to write lock free algos since most likely you will fail to get it right on all CPU architectures. void Experienced() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); t1.Wait(); t2.Wait(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Experienced did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Experienced() { for (int i = 0; i < Increments; i++) { Interlocked.Increment(ref Counter); } } Since time does move forward we do not use threads explicitly anymore but the much nicer Task abstraction which was introduced with .NET 4 at 2010. It is educational to look at the generated assembly code. The Interlocked.Increment method must be called which does wondrous things right? Lets see: lock inc dword ptr [eax] The first thing to note that there is no method call at all. Why? Because the JIT compiler does know very well about CPU intrinsic functions. Atomic operations which do lock the memory bus to prevent other processors to read stale values are such things. Second: This is the same increment call prefixed with a lock instruction. The only reason for the existence of the Interlocked class is that the JIT compiler can compile it to the matching CPU intrinsic functions which can not only increment by one but can also do an add, exchange and a combined compare and exchange operation. But be warned that the correct usage of its methods can be tricky. If you try to be clever and look a the generated IL code and try to reason about its efficiency you will fail. Only the generated machine code counts. Is this the best code we can write? Perhaps. It is nice and clean. But can we make it any faster? Lets see how good we are doing currently. Level Time in s IJustLearnedToUseThreads Flawed Code Intermediate 1,5 (lock) Experienced 0,3 (Interlocked.Increment) Master 0,1 (1,0 for int[2]) That lock free thing is really a nice thing. But if you read more about CPU cache, cache coherency, false sharing you can do even better. int[] Counters = new int[12]; // Cache line size is 64 bytes on my machine with an 8 way associative cache try for yourself e.g. 64 on more modern CPUs void Master() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Master, 0); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Master, Counters.Length - 1); t1.Wait(); t2.Wait(); Counter = Counters[0] + Counters[Counters.Length - 1]; if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Master did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Master(object number) { int index = (int) number; for (int i = 0; i < Increments; i++) { Counters[index]++; } } The key insight here is to use for each core its own value. But if you simply use simply an integer array of two items, one for each core and add the items at the end you will be much slower than the lock free version (factor 3). Each CPU core has its own cache line size which is something in the range of 16-256 bytes. When you do access a value from one location the CPU does not only fetch one value from main memory but a complete cache line (e.g. 16 bytes). This means that you do not pay for the next 15 bytes when you access them. This can lead to dramatic performance improvements and non obvious code which is faster although it does have many more memory reads than another algorithm. So what have we done here? We have started with correct code but it was lacking knowledge how to use the .NET Base Class Libraries optimally. Then we did try to get fancy and used threads for the first time and failed. Our next try was better but it still had non obvious issues (lock object exposed to the outside). Knowledge has increased further and we have found a lock free version of our counter which is a nice and clean way which is a perfectly valid solution. The last example is only here to show you how you can get most out of threading by paying close attention to your used data structures and CPU cache coherency. Although we are working in a virtual execution environment in a high level language with automatic memory management it does pay off to know the details down to the assembly level. Only if you continue to learn and to dig deeper you can come up with solutions no one else was even considering. I have studied particle physics which does help at the digging deeper part. Have you ever tried to solve Quantum Chromodynamics equations? Compared to that the rest must be easy ;-). Although I am no longer working in the Science field I take pride in discovering non obvious things. This can be a very hard to find bug or a new way to restructure data to make something 10 times faster. Now I need to get some sleep ….

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• Quick and Good: ( Requirement -> Validation -> Design ) for self use?

  - by Yugal Jindle

  How to casually do the required Software Engineering and designing? I am an inexperienced developer and face the following problem: My company is a start up and has no fix Software engineering systems. I am assigned tasks with not very clear and conflicting requirements. I don't have to follow any designs or verify requirements officially. Problem: I code all day and finally get stuck where requirement conflicts and I have to start over again. I can-not spend a lot of time doing proper SRS or SDD. How should I: List out Requirements for myself. (Not an official document) How to verify and validate the requirements? How to visualize them? How to design them with minimum effort? (As its going to be with me only) I don't want to waste my time coding something that's gonna collapse according to requirement conflict or something! I don't want to compromise with quality but don't want to re-write everything on some change that I didn't expected. I imagine making a diagram for my thought process that will show me conflict in the diagram itself, then finally correcting the diagram - I decide my design and structure my code in terms of interfaces or something. And then finally start implementing my design. I am able to sense the lack of systematic approach, but don't know how to proceed! Update: Please suggest me some tools that can ask me the questions and help me aggregate important details. How can I have diagram that I talked about for requirement verification?

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• Windows Phone 7 Design using Expression Blend - Resources

  - by Nikita Polyakov

  I’ve been doing a series of talks across Florida regarding Windows Phone 7 Design using Microsoft Expression Blend 4. I discuss the WP7 phone and application experience; show how to use Expression Blend toolset to effectively design such apps. Next presentation is on 5/4/2010 at 6:30PM EST will be a webcast format over LiveMeeting at Ft. Lauderdale Online group. Registration and the LiveMeeting link are both here: http://www.fladotnet.com/Reg.aspx?EventID=459 [I will post a link if it’s recorded]   Here are the resources from my presentations: The Biggest source is the Windows Phone UI and Design Language video from MIX10 Windows Phone 7 Design Guide as it’s found on the WP7 Dev Home Page Study The Silverlight Mobile Tutorials on official Silverlight website I will be blogging a separate entry for a new demo app that will showcase the elements I presented. I suggest you actually watch all of the MIX videos about SL and Design as great primer to get you thinking the WP7 way.   A lot happening with WP7Dev and it’s just the beginning! So watch these Twitter accounts and blogs: @Ckindel - Charlie Kindel - WP7 Dev Head http://blogs.msdn.com/ckindel @WP7Dev - Official Dev Twitter @WP7 - Official WP7 Twitter Peter Torr - http://blogs.msdn.com/ptorr Mike Harsh - http://blogs.msdn.com/mharsh Shawn Oster - http://www.shawnoster.com   Other worthwhile mention my local friends speaking and blogging about Windows Phone 7: Bill Reiss is doing great presentations on Building games with XNA for Windows Phone 7. Be on the lookout for those around Florida. Bill is a Silverlight MVP and has a legacy of XNA and Silverlight games, see his site. Kevin Wolf aka ByteMaster he is a Device Application Developer MVP with tremendous experience building mobile applications. He has developed WinMo-GF a multi-platform gaming framework. Get these tools and get creating! You will need the following components installed in this order: Expression Blend 4 Beta Windows Phone Developer Tools Microsoft Expression Blend Add-in Preview for Windows Phone Microsoft Expression Blend SDK Preview for Windows Phone Want more training? Don’t forget that Channel 9 has complete walkthroughs of their WP7 Training Kit posted online. PS: To continue with all this design talk check out Microsoft .toolbox “Learn to create Silverlight applications using Expression Studio and to apply fundamental design principles.” A great website with a lot of design tutorials set up as a wonderful full course on design all for free, including a great forum community and neat little avatars you can build yourself.

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• Design a T-shirt for .NET Reflector Pro

  - by Laila

  Win a .NET Reflector Pro license, a box of Red Gate goodies, and a t-shirt printed with your design! Red Gate likes t-shirts. Each of our teams has one. In fact, each individual person has one, numbered according to when they joined the company: Red Gate's 1st, 2nd, and so on right up to Red Gate's 170th, with the slogan "More than just a number". Those t-shirts are important, chiefly because they remind the people wearing them that they are important. But that isn't enough. What really makes us great are the people who choose to use our tools. So we'd like to extend our tradition of t-shirts to include you and put the design of our next shirt entirely in your hands. We'd like you to come up with a witty slogan or create an inventive or simply beautiful t-shirt design for .NET Reflector Pro, our add-in for Visual Studio, which allows you to step into decompiled assemblies whilst debugging in Visual Studio. When you're done, post your masterpiece to Twitter with the hash tag #reflectortees, and @redgate will take a look! We'll pick the best design, and the winner will get a licensed copy of .NET Reflector Pro and a box of Red Gate goodies - not to mention a copy of their t-shirt. The winning design will go into production and be worn and given out at tradeshows, conferences, and user group events across the world, proudly bearing the name of their designer. We'll also pick three runners-up who will receive licenses for .NET Reflector Pro. Red Gate goodie box Interested? If you're up for the challenge, then we've got some resources to get you started. Inside the .zip file you'll find high-quality versions of the following: T-shirt templates: don't forget to design the front and the back! Different versions of the .NET Reflector Pro logo and Red Gate logo. Colour sheets to give you an easy reference to the Red Gate colours, including hex and RGB values. You can create and send us as many designs as you like, and each of them will be considered for the prize. To submit your designs, simply tweet including the competition hash tag, #reflectortees, and a link to somewhere we can see your design: either an image hosting site such as Twitpic, Flickr or Picasa, or a personal blog. You will need to create a Twitter account (which is free), if you don't already have one. You only have three limits: The background colour of the t-shirt should be one of our brand colours (red, light/dark grey or black), though you're welcome to use other colours in the rest of the design. You need to make use of either the .NET Reflector Pro logo OR the Red Gate logo (please keep them as they are) If you include any text or slogan, stick with just one or two colors for it. Apart from that, go wild. Go and do whatever it is you do when you get creative: whether you walk barefoot on the grass with a pencil and paper, sit cross-legged on a pile of cushions with a laptop, or simply close your eyes and float through a mist of ideas, now is your chance. Make sure you enjoy it. We're looking forward to seeing your creations. Terms and conditions 1. The closing date for entries is June 11th, 2010 (4 p.m. UK time). Red Gate Software Ltd reserves the right to extend the competition deadline at its discretion. If there is a revision, the revised date will be published on this blog and the date for announcing the results will be postponed accordingly. 2. The winning designer will be notified on June 14th, 2010 through Twitter. The winner must claim his/her prize by sending us a high-resolution image of their design via email (i.e. Illustrator EPS files or appropriate format, ideally at 300dpi). If the winner does not come forward within 3 days of the announcement, they will forfeit their prize and another winner will be selected from the runners-up. The names of the winner and runners-up will be posted on this blog by June 18th.  3. Entry is completed on the designer posting a link to their entry in a tweet with the correct hash tag, #reflectortees. 4. Red Gate Software needs to hold the rights to using the winning design in order to put the t-shirt into production. We will make sure that this is fine with the winner before we do so, but if you do not want us holding the rights to your design, please do not submit your designs. We reserve the right to slightly alter or adjust any artwork we decide to use (mainly to make it easier to print), but we will make sure we contact the winner for approval first. The winner will also need to allow us the use of his/her name for purposes of promoting your design. 5. Entries must be entirely your own original work and must not breach any copyright or third party rights. Red Gate Software Ltd will not be made partially or fully liable for any non-original work submitted by you. 6. This competition is free: you do not need to buy anything or be an existing customer to enter. 7. This competition is not open to employees of Red Gate Software Ltd, their families, or any other company directly connected with the administration of this promotion.

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• Windows Azure Evolution - Web Sites (aka Antares) Part 1

  - by Shaun

  This is the 3rd post of my Windows Azure Evolution series, focus on the new features and enhancement which was alone with the Windows Azure Platform Upgrade June 2012, announced at the MEET Windows Azure event on 7th June. In the first post I introduced the new preview developer portal and how to works for the existing features such as cloud services, storages and SQL databases. In the second one I talked about the Windows Azure .NET SDK 1.7 on the latest Visual Studio 2012 RC on Windows 8. From this one I will begin to introduce some new features. Now let’s have a look on the first one of them, Windows Azure Web Sites.   Overview Windows Azure Web Sites (WAWS), as known as Antares, was a new feature still in preview stage in this upgrade. It allows people to quickly and easily deploy websites to a highly scalable cloud environment, uses the languages and open source apps of the choice then deploy such as FTP, Git and TFS. It also can be integrated with Windows Azure services like SQL Database, Caching, CDN and Storage easily. After read its introduction we may have a question: since we can deploy a website from both cloud service web role and web site, what’s the different between them? So, let’s have a quick compare.   CLOUD SERVICE WEB SITE OS Windows Server Windows Server Virtualization Windows Azure Virtual Machine Windows Azure Virtual Machine Host IIS IIS Platform ASP.NET WebForm, ASP.NET MVC, WCF ASP.NET WebForm, ASP.NET MVC, PHP Language C#, VB.NET C#, VB.NET, PHP Database SQL Database SQL Database, MySQL Architecture Multi layered, background worker, message queuing, etc.. Simple website with backend database. VS Project Windows Azure Cloud Service ASP.NET Web Form, ASP.NET MVC, etc.. Out-of-box Gallery (none) Drupal, DotNetNuke, WordPress, etc.. Deployment Package upload, Visual Studio publish FTP, Git, TFS, WebMatrix Compute Mode Dedicate VM Shared Across VMs, Dedicate VM Scale Scale up, scale out Scale up, scale out As you can see, there are many difference between the cloud service and web site, but the main point is that, the cloud service focus on those complex architecture web application. For example, if you want to build a website with frontend layer, middle business layer and data access layer, with some background worker process connected through the message queue, then you should better use cloud service, since it provides full control of your code and application. But if you just want to build a personal blog or a  business portal, then you can use the web site. Since the web site have many galleries, you can create them even without any coding and configuration. David Pallmann have an awesome figure explains the benefits between the could service, web site and virtual machine.   Create a Personal Blog in Web Site from Gallery As I mentioned above, one of the big feature in WAWS is to build a website from an existing gallery, which means we don’t need to coding and configure. What we need to do is open the windows azure developer portal and click the NEW button, select WEB SITE and FROM GALLERY. In the popping up windows there are many websites we can choose to use. For example, for personal blog there are Orchard CMS, WordPress; for CMS there are DotNetNuke, Drupal 7, mojoPortal. Let’s select WordPress and click the next button. The next step is to configure the web site. We will need to specify the DNS name and select the subscription and region. Since the WordPress uses MySQL as its backend database, we also need to create a MySQL database as well. Windows Azure Web Sites utilize ClearDB to host the MySQL databases. You cannot create a MySQL database directly from SQL Databases section. Finally, since we selected to create a new MySQL database we need to specify the database name and region in the last step. Also we need to accept the ClearDB’s terms as well. Then windows azure platform will download the WordPress codes and deploy the MySQL database and website. Then it will be ready to use. Select the website and click the BROWSE button, the WordPress administration page will be shown. After configured the WordPress here is my personal web blog on the cloud. It took me no more than 10 minutes to establish without any coding.   Monitor, Configure, Scale and Linked Resources Let’s click into the website I had just created in the portal and have a look on what we can do. In the website details page where are five sections. - Dashboard The overall information about this website, such as the basic usage status, public URL, compute mode, FTP address, subscription and links that we can specify the deployment credentials, TFS and Git publish setting, etc.. - Monitor Some status information such as the CPU usage, memory usage etc., errors, etc.. We can add more metrics by clicking the ADD METRICS button and the bottom as well. - Configure Here we can set the configurations of our website such as the .NET and PHP runtime version, diagnostics settings, application settings and the IIS default documents. - Scale This is something interesting. In WAWS there are two compute mode or called web site mode. One is “shared”, which means our website will be shared with other web sites in a group of windows azure virtual machines. Each web site have its own process (w3wp.exe) with some sandbox technology to isolate from others. When we need to scaling-out our web site in shared mode, we actually increased the working process count. Hence in shared mode we cannot specify the virtual machine size since they are shared across all web sites. This is a little bit different than the scaling mode of the cloud service (hosted service web role and worker role). The other mode called “dedicate”, which means our web site will use the whole windows azure virtual machine. This is the same hosting behavior as cloud service web role. In web role it will be deployed on the virtual machines we specified and all of them are only used by us. In web sites dedicate mode, it’s the same. In this mode when we scaling-out our web site we will use more virtual machines, and each of them will only host our own website. And we can specify the virtual machine size in this mode. In the developer portal we can select which mode we are using from the scale section. In shared mode we can only specify the instance count, but in dedicate mode we can specify the instance size as well as the instance count. - Linked Resource The MySQL database created alone with the creation of our WordPress web site is a linked resource. We can add more linked resources in this section.   Pricing For the web site itself, since this feature is in preview period if you are using shared mode, then you will get free up to 10 web sites. But if you are using dedicate mode, the price would be the virtual machines you are using. For example, if you are using dedicate and configured two middle size virtual machines then you will pay $230.40 per month. If there is SQL Database linked to your web site then they will be charged separately based on the Pay-As-You-Go price. For example a 1GB web edition database costs $9.99 per month. And the bandwidth will be charged as well. For example 10GB outbound data transfer costs $1.20 per month. For more information about the pricing please have a look at the windows azure pricing page.   Summary Windows Azure Web Sites gives us easier and quicker way to create, develop and deploy website to window azure platform. Comparing with the cloud service web role, the WAWS have many out-of-box gallery we can use directly. So if you just want to build a blog, CMS or business portal you don’t need to learn ASP.NET, you don’t need to learn how to configure DotNetNuke, you don’t need to learn how to prepare PHP and MySQL. By using WAWS gallery you can establish a website within 10 minutes without any lines of code. But in some cases we do need to code by ourselves. We may need to tweak the layout of our pages, or we may have a traditional ASP.NET or PHP web application which needed to migrated to the cloud. Besides the gallery WAWS also provides many features to download, upload code. It also provides the feature to integrate with some version control services such as TFS and Git. And it also provides the deploy approaches through FTP and Web Deploy. In the next post I will demonstrate how to use WebMatrix to download and modify the website, and how to use TFS and Git to deploy automatically one our code changes committed.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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• Is MVC a Design Pattern or Architectural pattern

  - by JCasso

  According to Sun and Msdn it is a design pattern. According to Wikipedia it is an architectural pattern In comparison to design patterns, architectural patterns are larger in scale. (Wikipedia - Architectural pattern) Or it is an architectural pattern that also has a design pattern ? Which one is true ?

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• Are ORM's counterproductive to OO design?

  - by Jeremiah

  In OOD, design of an object is said to be characterized by its identity and behavior. Having used OR/M's in the past, the primary purpose, in my opinion, revolves around the ability to store/retrieve data. That is to say, OR/M objects are not design by behavior, but rather data (i.e. database tables). Case and point: Many OR/M tools come with a point-to-a-database-table-and-click-object-generator. If objects are no longer characterized by behavior this will, in my opinion, muddy the identity and responsibility of the objects. Subsequently, if objects are not defined by a responsibility this could lend a hand to having tightly coupled classes and overall poor design. Furthermore, I would think that in an application setting, you would be heading towards scalability issues. So, my question is, do you think that ORM's are counterproductive to OO design? Perhaps the underlying question would be whether or not they are counterproductive to application development.

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• What design patterns are used here?

  - by TheMachineCharmer

  Diagram.net is good diagramming tool. I need to understand what design patterns are used by this tool so that I can understand how it works. What design patterns are used in this tool? What design patterns are generally used for diagramming tools?

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• database design suggestion needed

  - by JMSA

  I need to design a table for daily sales of pharmaceutical products. There are hundreds of types of products available {Name, code}. Thousands of sales-persons are employed to sell those products{name, code}. They collect products from different depots{name, code}. They work in different Areas - Zones - Markets - Outlets, etc. {All have names and codes} Each product has various types of prices {Production Price, Trade Price, Business Price, Discount Price, etc.}. And, sales-persons are free to choose from those combination to estimate the sales price. The problem is, daily sales requires huge amount of data-entry. Within couple of years there may be gigabytes of data (if not terabytes). If I need to show daily, weekly, monthly, quarterly and yearly sales reports there will be various types of sql queries I shall need. This is my initial design: Product {ID, Code, Name, IsActive} ProductXYZPriceHistory {ID, ProductID, Date, EffectDate, Price, IsCurrent} SalesPerson {ID, Code, Name, JoinDate, and so on..., IsActive} SalesPersonSalesAraeaHistory {ID, SalesPersonID, SalesAreaID, IsCurrent} Depot {ID, Code, Name, IsActive} Outlet {ID, Code, Name, AreaID, IsActive} AreaHierarchy {ID, Code, Name, PrentID, AreaLevel, IsActive} DailySales {ID, ProductID, SalesPersonID, OutletID, Date, PriceID, SalesPrice, Discount, etc...} Now, apart from indexing, how can I normalize my DailySales table to have a fine grained design that I shall not need to change for years to come? Please show me a sample design of only the DailySales data-entry table (from which all types of reports would be queried) on the basis of above information. I don't need a detailed design advice. I just need an advice regarding only the DailySales table. Is there any way to break this particular table to achieve granularity?

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• Design Help! How can design Extended properties for Entity with simple and complex data in extended

  - by mmtemporary

  I have design question. I have entity such as "Person". Person has properties such as: FirstName, LastName, Gender, BirthDate, .... End user when create a person in application may be need to define another property that is not defined in database table schema (or class person). for example: end user nead to define "property1" that its a string property. or nead define "proerty2" that its a image, or need define "property3" that its complex type. please separate your design solution in tow level: 1-database table design 2-class design thank u.

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• Is MFC is based on any design pattern,if so which design pattern??

  - by Vikram

  Is MFC is based on any design pattern,if so which design pattern??

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• Design pattern for adding / removing elements

  - by de3

  Wikipedia's definition for Iterator pattern design: the Iterator pattern is a design pattern in which iterators are used to access the elements of an aggregate object sequentially without exposing its underlying implementation. Iterator interface in java provides the following methods hasNext() next() remove() Is there a pattern design, or a java interface for inserting / deleting elements, and getting length of the aggregate object, in addition to iterating them? I know remove() is an optional method that can be used once per call to next(), but I am implementing a circular FIFO array and need a method delete() independent of iterator's next().

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• Design Pattern for "Context Sensitive" Right Click Menu

  - by MadSeb

  Hi, What is a design pattern I can use for generating "context-sensitive" right click menus ? I have in mind a "Windows Explorer"-like application where a user can right click on a folder and get a list of menu items but right click on a drive and get a totally different list. What design pattern should I use ? Would the factory design pattern be appropiate for handling such a menu ? Regards, Seb

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• What is the difference between design and architecture?

  - by MainID

  What is the difference between design and architecture?

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• DB Design to store custom fields for a table

  - by Fazal

  Hi All, this question came up based on the responses I got for the question http://stackoverflow.com/questions/2785033/getting-wierd-issue-with-to-number-function-in-oracle As everyone suggested that storing Numeric values in VARCHAR2 columns is not a good practice (which I totally agree with), I am wondering about a basic Design choice our team has made and whether there are better way to design. Problem Statement : We Have many tables where we want to give certain number of custom fields. The number of required custom fields is known, but what kind of attribute is mapped to the column is available to the user E.g. I am putting down a hypothetical scenario below Say you have a laptop which stores 50 attribute values for every laptop record. Each laptop attributes are created by the some admin who creates the laptop. A user created a laptop product lets say lap1 with attributes String, String, numeric, numeric, String Second user created laptop lap2 with attributes String,numeric,String,String,numeric Currently there data in our design gets persisted as following Laptop Table Id Name field1 field2 field3 field4 field5 1 lap1 lappy lappy 12 13 lappy 2 lap2 lappy2 13 lappy2 lapp2 12 This example kind of simulates our requirement and our design Now here if somebody is lookinup records for lap2 table doing a comparison on field2, We need to apply TO_NUMBER. select * from laptop where name='lap2' and TO_NUMBER(field2) < 15 TO_NUMBER fails in some cases when query plan decides to first apply to_number instead of the other filter. QUESTION Is this a valid design? What are the other alternative ways to solve this problem One of our team mates suggested creating tables on the fly for such cases. Is that a good idea How do popular ORM tools give custom fields or flex fields handling? I hope I was able to make sense in the question. Sorry for such a long text.. This causes us to use TO_NUMBER when queryio

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