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• Best of OTN - Week of Oct 21st

  - by CassandraClark-OTN

  This week's Best of OTN, for you, the best devs, dba's, sysadmins and architects out there!  In these weekly posts the OTN team will highlight the top content from each community; Architect, Database, Systems and Java.  Since we'll be publishing this on Fridays, we'll also mix in a little fun! Architect Community Top Content- The Road Ahead for WebLogic 12c | Edwin BiemondOracle ACE Edwin Biemond shares his thoughts on announced new features in Oracle WebLogic 12.1.3 & 12.1.4 and compares those upcoming releases to Oracle WebLogic 12.1.2. A Roadmap for SOA Development and Delivery | Mark NelsonDo you know the way to S-O-A? Mark Nelson does. His latest blog post, part of an ongoing series, will help to keep you from getting lost along the way. Updated ODI Statement of Direction | Robert SchweighardtHeads up Oracle Data Integrator fans! A new statement of product direction document is available, offering an overview of the strategic product plans for Oracle’s data integration products for bulk data movement and transformation, specifically Oracle Data Integrator (ODI) and Oracle Warehouse Builder (OWB). Bob Rhubart, Architect Community Manager Friday Funny - "Some people approach every problem with an open mouth." — Adlai E. Stevenson (October 23, 1835 – June 14, 1914) 23rd Vice President of the United States Database Community Top Content - Pre-Built Developer VMs (for Oracle VM VirtualBox)Heard all the chatter about Oracle VirtualBox? Over 1 million downloads per week and look: pre-built virtual appliances designed specifically for developers. Video: Big Data, or BIG DATA?Oracle Ace Director Ben Prusinski explains the differences.?? Webcast Series - Developing Applications in Oracle's Public CloudTime to get started on developing and deploying cloud applications by moving to the cloud. Good friend Gene Eun from Oracle's Cloud team posted this two-part Webcast series that has an overview and demonstration of the Oracle Database Cloud Service. Check out the demos on how to migrate your data to the cloud, extend your application with interactive reporting, and create and access RESTful Web services. Registration required, but so worth it! Laura Ramsey, Database Community Manager Friday Funny - Systems Community Top Content - Video: What Kind of Scalability is Better, Horizontal or Vertical?Rick Ramsey asks the question "Is Oracle's approach to large vertically scaled servers at odds with today's trend of combining lots and lots of small, low-cost servers systems with networking to build a cloud, or is it a better approach?" Michael Palmeter, Director of Solaris Product Management, and Renato Ribeiro, Director Product Management for SPARC Servers, discuss.Video: An Engineer Takes a Minute to Explain CloudBart Smaalders, long-time Oracle Solaris core engineer, takes a minute to explain cloud from a sysadmin point of view. ?Hands-On Lab: How to Deploy and Manage a Private IaaS Cloud Soup to nuts. This lab shows you how to set up and manage a private cloud with Oracle Enterprise Manager Cloud Control 12c in an Infrastructure as a service (IaaS) model. You will first configure the IaaS cloud as the cloud administrator and then deploy guest virtual machines (VMs) as a self-service user. Rick Ramsey, Systems Community Manager Friday Funny - Video: Drunk Airline Pilot - Dean Martin - Foster Brooks Java Community Top Content - Video: NightHacking Interview with James GoslingJames Gosling, the Father of Java, discusses robotics, Java and how to keep his autonomous WaveGliders in the ocean for weeks at a time. Live from Hawaii.  Video: Raspberry Pi Developer Challenge: Remote Controller A developer who knew nothing about Java Embedded or Raspberry Pi shows how he can now control a robot with his phone. The project was built during the Java Embedded Challenge for Raspberry Pi at JavaOne 2013.Java EE 7 Certification Survey - Participants NeededHelp us define how to server your training and certification needs for Java EE 7. Tori Wieldt, Java Community Manager Friday Funny - Programmers have a strong sensitivity to Yak's pheromone. Causes irresistible desire to shave said Yak. Thanks, @rickasaurus! To follow and take part in the conversation follow/like etc. at one or all of the resources below -  OTN TechBlog The Java Source Blog The OTN Garage Blog The OTN ArchBeat Blog @oracletechnet @java @OTN_Garage @OTNArchBeat @OracleDBDev OTN I Love Java OTN Garage OTN ArchBeat Oracle DB Dev OTN Java

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• Guest blog: A Closer Look at Oracle Price Analytics by Will Hutchinson

  - by Takin Babaei

  Overview:  Price Analytics helps companies understand how much of each sale goes into discounts, special terms, and allowances. This visibility lets sales management see the panoply of discounts and start seeing whether each discount drives desired behavior. In Price Analytics monitors parts of the quote-to-order process, tracking quotes, including the whole price waterfall and seeing which result in orders. The “price waterfall” shows all discounts between list price and “pocket price”. Pocket price is the final price the vendor puts in its pocket after all discounts are taken. The value proposition: Based on benchmarks from leading consultancies and companies I have talked to, where they have studied the effects of discounting and started enforcing what many of them call “discount discipline”, they find they can increase the pocket price by 0.8-3%. Yes, in today’s zero or negative inflation environment, one can, through better monitoring of discounts, collect what amounts to a price rise of a few percent. We are not talking about selling more product, merely about collecting a higher pocket price without decreasing quantities sold. Higher prices fall straight to the bottom line. The best reference I have ever found for understanding this phenomenon comes from an article from the September-October 1992 issue of Harvard Business Review called “Managing Price, Gaining Profit” by Michael Marn and Robert Rosiello of McKinsey & Co. They describe the outsized impact price management has on bottom line performance compared to selling more product or cutting variable or fixed costs. Price Analytics manages what Marn and Rosiello call “transaction pricing”, namely the prices of a given transaction, as opposed to what is on the price list or pricing according to the value received. They make the point that if the vendor does not manage the price waterfall, customers will, to the vendor’s detriment. It also discusses its findings that in companies it studied, there was no correlation between discount levels and any indication of customer value. I urge you to read this article. What Price Analytics does: Price analytics looks at quotes the company issues and tracks them until either the quote is accepted or rejected or it expires. There are prebuilt adapters for EBS and Siebel as well as a universal adapter. The target audience includes pricing analysts, product managers, sales managers, and VP’s of sales, marketing, finance, and sales operations. It tracks how effective discounts have been, the win rate on quotes, how well pricing policies have been followed, customer and product profitability, and customer performance against commitments. It has the concept of price waterfall, the deal lifecycle, and price segmentation built into the product. These help product and sales managers understand their pricing and its effectiveness on driving revenue and profit. They also help understand how terms are adhered to during negotiations. They also help people understand what segments exist and how well they are adhered to. To help your company increase its profits and revenues, I urge you to look at this product. If you have questions, please contact me. Will HutchinsonMaster Principal Sales Consultant – Analytics, Oracle Corp. Will Hutchinson has worked in the business intelligence and data warehousing for over 25 years. He started building data warehouses in 1986 at Metaphor, advancing to running Metaphor UK’s sales consulting area. He also worked in A.T. Kearney’s business intelligence practice for over four years, running projects and providing training to new consultants in the IT practice. He also worked at Informatica and then Siebel, before coming to Oracle with the Siebel acquisition. He became Master Principal Sales Consultant in 2009. He has worked on developing ROI and TCO models for business intelligence for over ten years. Mr. Hutchinson has a BS degree in Chemical Engineering from Princeton University and an MBA in Finance from the University of Chicago.

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• New R Interface to Oracle Data Mining Available for Download

  - by charlie.berger

    The R Interface to Oracle Data Mining ( R-ODM) allows R users to access the power of Oracle Data Mining's in-database functions using the familiar R syntax. R-ODM provides a powerful environment for prototyping data analysis and data mining methodologies. R-ODM is especially useful for: Quick prototyping of vertical or domain-based applications where the Oracle Database supports the application Scripting of "production" data mining methodologies Customizing graphics of ODM data mining results (examples: classification, regression, anomaly detection) The R-ODM interface allows R users to mine data using Oracle Data Mining from the R programming environment. It consists of a set of function wrappers written in source R language that pass data and parameters from the R environment to the Oracle RDBMS enterprise edition as standard user PL/SQL queries via an ODBC interface. The R-ODM interface code is a thin layer of logic and SQL that calls through an ODBC interface. R-ODM does not use or expose any Oracle product code as it is completely an external interface and not part of any Oracle product. R-ODM is similar to the example scripts (e.g., the PL/SQL demo code) that illustrates the use of Oracle Data Mining, for example, how to create Data Mining models, pass arguments, retrieve results etc. R-ODM is packaged as a standard R source package and is distributed freely as part of the R environment's Comprehensive R Archive Network (CRAN). For information about the R environment, R packages and CRAN, see www.r-project.org. R-ODM is particularly intended for data analysts and statisticians familiar with R but not necessarily familiar with the Oracle database environment or PL/SQL. It is a convenient environment to rapidly experiment and prototype Data Mining models and applications. Data Mining models prototyped in the R environment can easily be deployed in their final form in the database environment, just like any other standard Oracle Data Mining model. What is R? R is a system for statistical computation and graphics. It consists of a language plus a run-time environment with graphics, a debugger, access to certain system functions, and the ability to run programs stored in script files. The design of R has been heavily influenced by two existing languages: Becker, Chambers & Wilks' S and Sussman's Scheme. Whereas the resulting language is very similar in appearance to S, the underlying implementation and semantics are derived from Scheme. R was initially written by Ross Ihaka and Robert Gentleman at the Department of Statistics of the University of Auckland in Auckland, New Zealand. Since mid-1997 there has been a core group (the "R Core Team") who can modify the R source code archive. Besides this core group many R users have contributed application code as represented in the near 1,500 publicly-available packages in the CRAN archive (which has shown exponential growth since 2001; R News Volume 8/2, October 2008). Today the R community is a vibrant and growing group of dozens of thousands of users worldwide. It is free software distributed under a GNU-style copyleft, and an official part of the GNU project ("GNU S"). Resources: R website / CRAN R-ODM

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• ArchBeat Link-o-Rama Top 10 for December 9-15, 2012

  - by Bob Rhubart

  You click, we listen. The following list reflects the Top 10 most popular items posted on the OTN ArchBeat Facefbook page for the week of December 9-15, 2012. DevOps Basics II: What is Listening on Open Ports and Files – WebLogic Essentials | Dr. Frank Munz "Can you easily find out which WebLogic servers are listening to which port numbers and addresses?" asks Dr. Frank Munz. The good doctor has an answer—and a tech tip. Using OBIEE against Transactional Schemas Part 4: Complex Dimensions | Stewart Bryson "Another important entity for reporting in the Customer Tracking application is the Contact entity," says Stewart Bryson. "At first glance, it might seem that we should simply build another dimension called Dim – Contact, and use analyses to combine our Customer and Contact dimensions along with our Activity fact table to analyze Customer and Contact behavior." SOA 11g Technology Adapters – ECID Propagation | Greg Mally "Many SOA Suite 11g deployments include the use of the technology adapters for various activities including integration with FTP, database, and files to name a few," says Oracle Fusion Middleware A-Team member Greg Mally. "Although the integrations with these adapters are easy and feature rich, there can be some challenges from the operations perspective." Greg's post focuses on technical tips for dealing with one of these challenges. Podcast: DevOps and Continuous Integration In Part 1 of a 3-part program, panelists Tim Hall (Senior Director of product management for Oracle Enterprise Repository and Oracle’s Application Integration Architecture), Robert Wunderlich (Principal Product Manager for Oracle’s Application Integration Architecture Foundation Pack) and Peter Belknap (Director of product management for Oracle SOA Integration) discuss why DevOps matters and how it changes development methodologies and organizational structure. Good To Know - Conflicting View Objects and Shared Entity | Andrejus Baranovskis Oracle ACE Director Andrejus Baranovskis shares his thoughts -- and a sample application -- dealing with an "interesting ADF behavior" encountered over the weekend. Cloud Deployment Models | B. R. Clouse Looking out for the cloud newbies... "As the cloud paradigm grows in depth and breadth, more readers are approaching the topic for the first time, or from a new perspective," says B. R. Clouse. "This blog is a basic review of cloud deployment models, to help orient newcomers and neophytes." Service governance morphs into cloud API management | David Linthicum "When building and using clouds, the ability to manage APIs or services is the single most important item you can provide to ensure the success of the project," says David Linthicum. "But most organizations driving a cloud project for the first time have no experience handling a service-based architecture and don't see the need for API management until after deployment. By then, it's too late." Oracle Fusion Middleware Security: Password Policy in OAM 11g R2 | Rob Otto Rob Otto continues the Oracle Fusion Middleware A-Team "Oracle Access Manager Academy" series with a detailed look at OAM's ability to support "a subset of password management processes without the need to use Oracle Identity Manager and LDAP Sync." Understanding the JSF Lifecycle and ADF Optimized Lifecycle | Steven Davelaar Could you call that a surprise ending? Oracle WebCenter & ADF Architecture Team (A-Team) member learned a lot more than he expected while creating a UKOUG presentation entitled "What you need to know about JSF to be succesful with ADF." Expanding on requestaudit - Tracing who is doing what...and for how long | Kyle Hatlestad "One of the most helpful tracing sections in WebCenter Content (and one that is on by default) is the requestaudit tracing," says Oracle Fusion Middleware A-Team architect Kyle Hatlestad. Get up close and technical in his post. Thought for the Day "There is no code so big, twisted, or complex that maintenance can't make it worse." — Gerald Weinberg Source: SoftwareQuotes.com

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• At the Java DEMOgrounds - Oracle Java ME Embedded Enables the “Internet of Things”

  - by Janice J. Heiss

  I caught up with Oracle’s Robert Barnes, Senior Director, Java Product Management, who was demonstrating a new product from Oracle’s Java Platform, Micro Edition (Java ME) product portfolio, Oracle Java ME Embedded 3.2, a complete client Java runtime optimized for microcontrollers and other resource-constrained devices. Oracle’s Java ME Embedded 3.2 is a Java ME runtime based on CLDC 1.1 (JSR-139) and IMP-NG (JSR-228).“What we are showing here is the Java ME Embedded 3.2 that we announced last week,” explained Barnes. “It’s the start of the 'Internet of Things,’ in which you have very very small devices that are on the edge of the network where the sensors sit. You often have a middle area called a gateway or a concentrator which is fairly middle to higher performance. On the back end you have a very high performance server. What this is showing is Java spanning all the way from the server side right down towards the type of chip that you will get at the sensor side as the network.” Barnes explained that he had two different demos running.The first, called the Solar Panel System Demo, measures the brightness of the light.  “This,” said Barnes, “is a light source demo with a Cortex M3 controlling the motor, on the end of which is a sensor which is measuring the brightness of the lamp. This is recording the data of the brightness of the lamp and as we move the lamp out of the way, we should be able using the server to turn the sensor towards the lamp so the brightness reading will go higher. This sends the message back to the server and we can look at the web server sitting on the PC underneath the desk. We can actually see the data being passed back effectively through a back office type of function within a utility environment.” The second demo, the Smart Grid Response Demo, Barnes explained, “has the same board and processor and is still using Java ME embedded with a different app on top. This is a demand response demo. What we are seeing within the managing environment is that people want to track the pricing signals of the electricity. If it’s particularly expensive at any point in time, they may turn something off. This demo sets the price of the electricity as though this is coming from the back of the server sending pricing signals to my home.” The demo had a lamp and a fan and it was tracking the price of electricity. “If I set the price of the electricity to go over 5 cents, then the device will turn off,” explained Barnes. “I can go into my settings and, in this case, change the price to 50 cents and we can wait a minus and the lamp will go off. When I change the pricing signal so that it is lower, the lamp will come back on. The key point is that the Java software we have running is the same across all the different devices; it’s a way to build applications across multiple devices using the same software. This is important because it fixes peak loading on the network and can stops blackouts.” This demo brought me back to a prior decade when Sun Microsystems first promoted  Jini technology, a version of Java that would put everything on the network and give us the smart home. Your home would be automated to tell you when you were out of milk, when to change your light bulbs, etc. You would have access to the web and the network throughout your home.It’s interesting to see how technology moves over time – from the smart home to the Internet of Things.

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• More Stuff less Fluff

  - by brendonpage

  Originally posted on: http://geekswithblogs.net/brendonpage/archive/2013/11/08/more-stuff-less-fluff.aspxYAGNI – "You Aren't Going To Need It". This is an acronym commonly used in software development to remind developers to only write what they need. This acronym exists because software developers have gotten into the habit of writing everything they need to solve a problem and then everything they think they're going to possibly need in the future. Since we can't predict the future this results in a large portion of the code that we write never being used. That extra code causes unnecessary complexity, which makes it harder to understand and harder to modify when we inevitably have to write something that we didn't think of. I've known about YAGNI for some time now but I never really got it. The words made sense and the idea was clear but the concept never sank in. I was one of those devs who'd happily write a ton of code in the anticipation of future needs. In my mind this was an essential part of writing high quality code. I didn't realise that in doing so I was actually writing low quality code. If you are anything like me you are probably thinking "Lies and propaganda! High quality code needs to be future proof." I agree! But what makes code future proof? If we could see into the future the answer would be simple, code that allows for or meets all future requirements. Since we can't see the future the best we can do is write code that can easily adapt to future requirements, this means writing flexible code. Flexible code is: Fast to understand. Fast to add to. Fast to modify. To be flexible code has to be simple, this means only making it as complex as it needs to be to meet those 3 criteria. That is high quality code. YAGNI! The art is in deciding where to place the seams (abstractions) that will give you flexibility without making decisions about future functionality. Robert C Martin explains it very nicely, he says a good architecture allows you to defer decisions because if you can defer a decision then you have the flexibility to change it. I've recently had a YAGNI experience which brought this all into perspective. I was working on a new project which had multiple clients that connect to a server hosted in the cloud. I was tasked with adding a feature to the desktop client that would allow users to capture items that would then be saved to the cloud. My immediate thought was "Hey we have multiple clients so I should build a web service for these items, that way we can access them from other clients", so I went to work and this is what I created.  I stood back and gazed upon what I'd created with a warm fuzzy feeling. It was beautiful! Then the time came for the team to use the design I'd created for another feature with a new entity. Let's just say that they didn't get the same warm fuzzy feeling that I did when they looked at the design. After much discussion they eventually got it through to me that I'd bloated the design based on an assumption of future functionality. After much more discussion we cut the design down to the following. This design gives us future flexibility with no extra work, it is as complex as it needs to be. It has been a couple of months since this incident and we still haven't needed to access either of the entities from other clients. Using the simpler design allowed us to do more stuff with less stuff!

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• Process Power to the People that Create Engagement

  - by Michael Snow

  Organizations often speak about their engagement problems as if the problem is the people they are trying to engage - employees,  partners, customers and citizens.  The reality of most engagement problems is that the processes put in place to engage are impersonal, inflexible, unintuitive, and often completely ignorant of the population they are trying to serve. Life, Liberty and the Pursuit of Delight? How appropriate during this short week of the US Independence Day Holiday that we're focusing on People, Process and Engagement. As we celebrate this holiday in the US and the historic independence we gained (sorry Brits!) - it's interesting to think back to 1776 to the creation of that pivotal document, the Declaration of Independence. What tremendous pressure to create an engaging document and founding experience they must have felt. "On June 11, 1776, in anticipation of the impending vote for independence from Great Britain, the Continental Congress appointed five men — Thomas Jefferson, John Adams, Benjamin Franklin, Roger Sherman, and Robert Livingston — to write a declaration that would make clear to people everywhere why this break from Great Britain was both necessary and inevitable. The committee then appointed Jefferson to draft a statement. Jefferson produced a "fair copy" of his draft declaration, which became the basic text of his "original Rough draught." The text was first submitted to Adams, then Franklin, and finally to the other two members of the committee. Before the committee submitted the declaration to Congress on June 28, they made forty-seven emendations to the document. During the ensuing congressional debates of July 1-4, 1776, Congress adopted thirty-nine further revisions to the committee draft. (http://www.constitution.org) If anything was an attempt for engaging the hearts and minds of the 13 Colonies at the time, this document certainly succeeded in its mission. ...Their tools at the time were pen and ink and parchment. Although the final document would later be typeset with lead type for a printing press to distribute to the colonies, all of the original drafts were hand written. And today's enterprise complains about using "Review and Track Changes" at times.  Can you imagine the manual revision control process? or lack thereof?  Collaborative process? Time delays? Would  implementing a better process have helped our founding fathers collaborate better? Declaration of Independence rough draft below. One of many during the creation process. Great comparison across multiple versions of the document here. (from http://www.ushistory.org/): While you may not be creating a new independent nation, getting your employees to engage is crucial to your success as a company in today's world. Oracle WebCenter provides the tools that power engagement. Employees that have better tools for communication, collaboration and getting their job done are more engaged employees. Better engaged employees create more engaged customers and partners. 12.00 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-size:10.0pt; font-family:"Times New Roman","serif"; mso-fareast-font-family:"Times New Roman";}

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• Hidden Features of C#?

  - by Serhat Özgel

  This came to my mind after I learned the following from this question: where T : struct We, C# developers, all know the basics of C#. I mean declarations, conditionals, loops, operators, etc. Some of us even mastered the stuff like Generics, anonymous types, lambdas, linq, ... But what are the most hidden features or tricks of C# that even C# fans, addicts, experts barely know? Here are the revealed features so far: Keywords yield by Michael Stum var by Michael Stum using() statement by kokos readonly by kokos as by Mike Stone as / is by Ed Swangren as / is (improved) by Rocketpants default by deathofrats global:: by pzycoman using() blocks by AlexCuse volatile by Jakub Šturc extern alias by Jakub Šturc Attributes DefaultValueAttribute by Michael Stum ObsoleteAttribute by DannySmurf DebuggerDisplayAttribute by Stu DebuggerBrowsable and DebuggerStepThrough by bdukes ThreadStaticAttribute by marxidad FlagsAttribute by Martin Clarke ConditionalAttribute by AndrewBurns Syntax ?? operator by kokos number flaggings by Nick Berardi where T:new by Lars Mæhlum implicit generics by Keith one-parameter lambdas by Keith auto properties by Keith namespace aliases by Keith verbatim string literals with @ by Patrick enum values by lfoust @variablenames by marxidad event operators by marxidad format string brackets by Portman property accessor accessibility modifiers by xanadont ternary operator (?:) by JasonS checked and unchecked operators by Binoj Antony implicit and explicit operators by Flory Language Features Nullable types by Brad Barker Currying by Brian Leahy anonymous types by Keith __makeref __reftype __refvalue by Judah Himango object initializers by lomaxx format strings by David in Dakota Extension Methods by marxidad partial methods by Jon Erickson preprocessor directives by John Asbeck DEBUG pre-processor directive by Robert Durgin operator overloading by SefBkn type inferrence by chakrit boolean operators taken to next level by Rob Gough pass value-type variable as interface without boxing by Roman Boiko programmatically determine declared variable type by Roman Boiko Static Constructors by Chris Easier-on-the-eyes / condensed ORM-mapping using LINQ by roosteronacid Visual Studio Features select block of text in editor by Himadri snippets by DannySmurf Framework TransactionScope by KiwiBastard DependantTransaction by KiwiBastard Nullable<T> by IainMH Mutex by Diago System.IO.Path by ageektrapped WeakReference by Juan Manuel Methods and Properties String.IsNullOrEmpty() method by KiwiBastard List.ForEach() method by KiwiBastard BeginInvoke(), EndInvoke() methods by Will Dean Nullable<T>.HasValue and Nullable<T>.Value properties by Rismo GetValueOrDefault method by John Sheehan Tips & Tricks nice method for event handlers by Andreas H.R. Nilsson uppercase comparisons by John access anonymous types without reflection by dp a quick way to lazily instantiate collection properties by Will JavaScript-like anonymous inline-functions by roosteronacid Other netmodules by kokos LINQBridge by Duncan Smart Parallel Extensions by Joel Coehoorn

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• Merge method in MergeSort Algorithm .

  - by Tony

  I've seen many mergeSort implementations .Here is the version in Data Structures and Algorithms in Java (2nd Edition) by Robert Lafore : private void recMergeSort(long[] workSpace, int lowerBound,int upperBound) { if(lowerBound == upperBound) // if range is 1, return; // no use sorting else { // find midpoint int mid = (lowerBound+upperBound) / 2; // sort low half recMergeSort(workSpace, lowerBound, mid); // sort high half recMergeSort(workSpace, mid+1, upperBound); // merge them merge(workSpace, lowerBound, mid+1, upperBound); } // end else } // end recMergeSort() private void merge(long[] workSpace, int lowPtr, int highPtr, int upperBound) { int j = 0; // workspace index int lowerBound = lowPtr; int mid = highPtr-1; int n = upperBound-lowerBound+1; // # of items while(lowPtr <= mid && highPtr <= upperBound) if( theArray[lowPtr] < theArray[highPtr] ) workSpace[j++] = theArray[lowPtr++]; else workSpace[j++] = theArray[highPtr++]; while(lowPtr <= mid) workSpace[j++] = theArray[lowPtr++]; while(highPtr <= upperBound) workSpace[j++] = theArray[highPtr++]; for(j=0; j<n; j++) theArray[lowerBound+j] = workSpace[j]; } // end merge() One interesting thing about merge method is that , almost all the implementations didn't pass the lowerBound parameter to merge method . lowerBound is calculated in the merge . This is strange , since lowerPtr = mid + 1 ; lowerBound = lowerPtr -1 ; that means lowerBound = mid ; Why the author didn't pass mid to merge like merge(workSpace, lowerBound,mid, mid+1, upperBound); ? I think there must be a reason , otherwise I can't understand why an algorithm older than half a center ,and have all coincident in the such little detail.

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• Best ways to teach a beginner to program?

  - by Justin Standard

  Original Question I am currently engaged in teaching my brother to program. He is a total beginner, but very smart. (And he actually wants to learn). I've noticed that some of our sessions have gotten bogged down in minor details, and I don't feel I've been very organized. (But the answers to this post have helped a lot.) What can I do better to teach him effectively? Is there a logical order that I can use to run through concept by concept? Are there complexities I should avoid till later? The language we are working with is Python, but advice in any language is welcome. How to Help If you have good ones please add the following in your answer: Beginner Exercises and Project Ideas Resources for teaching beginners Screencasts / blog posts / free e-books Print books that are good for beginners Please describe the resource with a link to it so I can take a look. I want everyone to know that I have definitely been using some of these ideas. Your submissions will be aggregated in this post. Online Resources for teaching beginners: A Gentle Introduction to Programming Using Python How to Think Like a Computer Scientist Alice: a 3d program for beginners Scratch (A system to develop programming skills) How To Design Programs Structure and Interpretation of Computer Programs Learn To Program Robert Read's How To Be a Programmer Microsoft XNA Spawning the Next Generation of Hackers COMP1917 Higher Computing lectures by Richard Buckland (requires iTunes) Dive into Python Python Wikibook Project Euler - sample problems (mostly mathematical) pygame - an easy python library for creating games Create Your Own Games With Python ebook Foundations of Programming for a next step beyond basics. Squeak by Example Recommended Print Books for teaching beginners Accelerated C++ Python Programming for the Absolute Beginner Code by Charles Petzold

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• code review: Is it subjective or objective(quantifiable) ?

  - by Ram

  I am putting together some guidelines for code reviews. We do not have one formal process yet, and trying to formalize it. And our team is geographically distributed We are using TFS for source control (used it for tasks/bug tracking/project management as well, but migrated that to JIRA) with VS2008 for development. What are the things you look for when doing a code review ? These are the things I came up with Enforce FXCop rules (we are a Microsoft shop) Check for performance (any tools ?) and security (thinking about using OWASP- code crawler) and thread safety Adhere to naming conventions The code should cover edge cases and boundaries conditions Should handle exceptions correctly (do not swallow exceptions) Check if the functionality is duplicated elsewhere method body should be small(20-30 lines) , and methods should do one thing and one thing only (no side effects/ avoid temporal coupling -) Do not pass/return nulls in methods Avoid dead code Document public and protected methods/properties/variables What other things do you generally look for ? I am trying to see if we can quantify the review process (it would produce identical output when reviewed by different persons) Example: Saying "the method body should be no longer than 20-30 lines of code" as opposed to saying "the method body should be small" Or is code review very subjective ( and would differ from one reviewer to another ) ? The objective is to have a marking system (say -1 point for each FXCop rule violation,-2 points for not following naming conventions,2 point for refactoring etc) so that developers would be more careful when they check in their code.This way, we can identify developers who are consistently writing good/bad code.The goal is to have the reviewer spend about 30 minutes max, to do a review (I know this is subjective, considering the fact that the changeset/revision might include multiple files/huge changes to the existing architecture etc , but you get the general idea, the reviewer should not spend days reviewing someone's code) What other objective/quantifiable system do you follow to identify good/bad code written by developers? Book reference: Clean Code: A handbook of agile software craftmanship by Robert Martin

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• Contact-to-hire from the perspective of the headhunter agency?

  - by jamieb

  I operate a small IT consulting firm. One of my clients has expressed an interest in having an ASP.Net programmer on-site at their location for a six-month contract, with an option to hire. I've never really operated my company as a body shop (renting out talent for the long term) and an unfamiliar with how to price my quote. Assume I were to bring on a new developer as a 1099'ed contractor and then contract that person out to my client for the duration of the project. If I'm billing my client $X per hour for this developer's time, what should I be compensating this developer? $X/2 per hour? What's the typical ratio? If the client decides to hire this person at the end of the contract, what should I be compensated? Is it a flat finders fee, or maybe a function of the developer's annual salary? Would there be any advantage to actually hiring the person as a 1040'd employee rather than a 1099 contractor even if I can't offer him benefits? I know other body shops (like Robert Half) do this and never understood why.

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• OOP 101 - quick question.

  - by R Bennett

  I've used procedural for sometime now and trying to get a better understanding of OOP in Php. Starting at square 1 and I have a quick question ot get this to gel. Many of the basic examples show static values ( $bob-name = "Robert";) when assigning a value, but I want to pass values... say from a form ( $name = $_POST['name']; ) class Person { // define properties public $name; public $weight; public $age; public function title() { echo $this->name . " has submitted a request "; } } $bob = new Person; // want to plug the value in here $bob->name = $name; $bob->title(); I guess I'm getting a little hung up in some areas as far as accessing variables from within the class, encapsulation & "rules", etc., can $name = $_POST['name']; reside anywhere outside of the class or am I missing an important point? Thanks

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• return an ArrayList method

  - by Bopeng Liu

  This is a drive method for two other classes. which i posted here http://codereview.stackexchange.com/questions/33148/book-program-with-arraylist I need some help for the private static ArrayList getAuthors(String authors) method. I am kind a beginner. so please help me finish this drive method. or give me some directions. Instruction some of the elements of the allAuthors array contain asterisks “*” between two authors names. The getAuthors method uses this asterisk as a delimiter between names to store them separately in the returned ArrayList of Strings. import java.util.ArrayList; public class LibraryDrive { public static void main(String[] args) { String[] titles = { "The Hobbit", "Acer Dumpling", "A Christmas Carol", "Marley and Me", "Building Java Programs", "Java, How to Program" }; String[] allAuthors = { "Tolkien, J.R.", "Doofus, Robert", "Dickens, Charles", "Remember, SomeoneIdont", "Reges, Stuart*Stepp, Marty", "Deitel, Paul*Deitel, Harvery" }; ArrayList<String> authors = new ArrayList<String>(); ArrayList<Book> books = new ArrayList<Book>(); for (int i = 0; i < titles.length; i++) { authors = getAuthors(allAuthors[i]); Book b = new Book(titles[i], authors); books.add(b); authors.remove(0); } Library lib = new Library(books); System.out.println(lib); lib.sort(); System.out.println(lib); } private static ArrayList<String> getAuthors(String authors) { ArrayList books = new ArrayList<String>(); // need help here. return books; } }

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• Delphi TRttiType.GetMethods return zero TRttiMethod instances

  - by conciliator

  I've recently been able to fetch a TRttiType for an interface using TRttiContext.FindType using Robert Loves "GetType"-workaround ("registering" the interface by an explicit call to ctx.GetType, e.g. RType := ctx.GetType(TypeInfo(IMyPrettyLittleInterface));). One logical next step would be to iterate the methods of said interface. Consider program rtti_sb_1; {$APPTYPE CONSOLE} uses SysUtils, Rtti, mynamespace in 'mynamespace.pas'; var ctx: TRttiContext; RType: TRttiType; Method: TRttiMethod; begin ctx := TRttiContext.Create; RType := ctx.GetType(TypeInfo(IMyPrettyLittleInterface)); if RType <> nil then begin for Method in RType.GetMethods do WriteLn(Method.Name); end; ReadLn; end. This time, my mynamespace.pas looks like this: IMyPrettyLittleInterface = interface ['{6F89487E-5BB7-42FC-A760-38DA2329E0C5}'] procedure SomeProcedure; end; Unfortunately, RType.GetMethods returns a zero-length TArray-instance. Are there anyone able to reproduce my troubles? (Note that in my example I've explicitly fetched the TRttiType using TRttiContext.GetType, not the workaround; the introduction is included to warn readers that there might be some unresolved issues regarding rtti and interfaces.) Thanks!

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• Script says Undefined

  - by user1058887

  I have this script that would let the user input a text and it would get translated into something else. It works only when the word has only 1 letter. When there is more than 1 letter it says Undefined. Here is the script : function copyit(theField) { var tempval=eval("document."+theField) tempval.focus() tempval.select() therange=tempval.createTextRange() therange.execCommand("Copy") } function results() { var behavior="form"; var text=document.csrAlpha.csrresult2.value; var ff22=text.toLowerCase(); var Words=new Array ; Words["b"]="Dadada"; Words["bob"]="Robert"; Words["flower"]="Banana"; Words["brad"]="Chair"; var trans=""; var regExp=/[\!@#$%^&*(),=";:\/]/; var stringCheck=regExp.exec(ff22); if(!stringCheck) { if(ff22.length > 0) { for(var i=0;i < ff22.length;i++) { var thisChar=ff22.charAt(i); trans += Words[thisChar] + " "; } } else { trans +="Please write something."; } } else { trans +="You entered invalid characters. Remove them and try again."; } document.csrAlpha.csrresult.value=trans; } Please insert your text below:

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• binary quicksort

  - by davit-datuashvili

  hi i want implement Binary quicksort algorithm from robert sedgewick book it looks like this public class quickb{ public static final int bitsword=32; public static void quicksortB(int a[],int l,int r,int d){ int i=l; int j=r-1; if (r<=l || d>bitsword) return ; while (j!=i) { while (digit(a[i],d)==0 && (i<j)) i++; while (digit(a[j],d)==1 && (j>i)) j++; int t=a[i]; a[i]=a[j]; a[j]=t; } if (digit(a[r-1],d)== 0) j++; quicksortB(a,l,j-1,d+1); quicksortB(a,j,r,d+1); } public static void main(String[]args){ int a[]=new int[]{4,7,3,9,8,2}; quicksortB(a,0,a.length-1,0); for (int i=0;i<a.length;i++){ System.out.println(a[i]); } } public static int digit(int m,int d){ return (m>>d)&1; } } but it show me error: java.lang.ArrayIndexOutOfBoundsException: 6 at quickb.quicksortB(quickb.java:13) at quickb.main(quickb.java:32) what is wrong?

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• Last week I was presented with a Microsoft MVP award in Virtual Machines – time to thank all who hel

  - by Liam Westley

  MVP in Virtual Machines Last week, on 1st April, I received an e-mail from Microsoft letting me know that I had been presented with a 2010 Microsoft® MVP Award for outstanding contributions in Virtual Machine technical communities during the past year.   It was an honour to be nominated, and is a great reflection on the vibrancy of the UK user group community which made this possible. Virtualisation for developers, not just IT Pros I consider it a special honour as my expertise in virtualisation is as a software developer utilising virtual machines to aid my software development, rather than an IT Pro who manages data centre and network infrastructure.  I’ve been on a minor mission over the past few years to enthuse developers in a topic usually seen as only for network admins, but which can make their life a whole lot easier once understood properly. Continuous learning is fun In 1676, the scientist Isaac Newton, in a letter to Robert Hooke used the phrase (http://www.phrases.org.uk/meanings/268025.html) ‘If I have seen a little further it is by standing on the shoulders of Giants’ I’m a nuclear physicist by education, so I am more than comfortable that any knowledge I have is based on the work of others.  Although far from a science, software development and IT is equally built upon the work of others. It’s one of the reasons I despise software patents. So in that sense this MVP award is a result of all the great minds that have provided virtualisation solutions for me to talk about.  I hope that I have always acknowledged those whose work I have used when blogging or giving presentations, and that I have executed my responsibility to share any knowledge gained as widely as possible. Thanks to all those who helped – a big thanks to the UK user group community I reckon this journey started in 2003 when I started attending a user group called the London .Net Users Group (http://www.dnug.org.uk) started by a nice chap called Ian Cooper. The great thing about Ian was that he always encouraged non professional speakers to take the stage at the user group, and my first ever presentation was on 30th September 2003; SQL Server CE 2.0 and the.NET Compact Framework. In 2005 Ian Cooper was on the committee for the first DeveloperDeveloperDeveloper! day, the free community conference held at Microsoft’s UK HQ in Thames Valley park in Reading.  He encouraged me to take part and so on 14th May 2005 I presented a talk previously given to the London .Net User Group on Simplifying access to multiple DB providers in .NET.  From that point on I definitely had the bug; presenting at DDD2, DDD3, groking at DDD4 and SQLBits I and after a break, DDD7, DDD Scotland and DDD8.  What definitely made me keen was the encouragement and infectious enthusiasm of some of the other DDD organisers; Craig Murphy, Barry Dorrans, Phil Winstanley and Colin Mackay. During the first few DDD events I met the Dave McMahon and Richard Costall from NxtGenUG who made it easy to start presenting at their user groups.  Along the way I’ve met a load of great user group organisers; Guy Smith-Ferrier of the .Net Developer Network, Jimmy Skowronski of GL.Net and the double act of Ray Booysen and Gavin Osborn behind what was Vista Squad and is now Edge UG. Final thanks to those who suggested virtualisation as a topic ... Final thanks have to go the people who inspired me to create my Virtualisation for Developers talk.  Toby Henderson (@holytshirt) ensured I took notice of Sun’s VirtualBox, Peter Ibbotson for being a fine sounding board at the Kew Railway over quite a few Adnam’s Broadside and to Guy Smith-Ferrier for allowing his user group to be the guinea pigs for the talk before it was seen at DDD7.  Thanks to all of you I now know much more about virtualisation than I would have thought possible and it continues to be great fun. Conclusion If this was an academy award acceptance speech I would have been cut off after the first few paragraphs, so well done if you made it this far.  I’ll be doing my best to do justice to the MVP award and the UK community.  I’m fortunate in having a new employer who considers presenting at user groups as a good thing, so don’t expect me to stop any time soon. If you’ve never seen me in action, then you can view the original DDD7 Virtualisation for Developers presentation (filmed by the Microsoft Channel 9 team) as part of the full DDD7 video list here, http://www.craigmurphy.com/blog/?p=1591.  Also thanks to Craig Murphy’s fine video work you can also view my latest DDD8 presentation on Commercial Software Development, here, http://vimeo.com/9216563 P.S. If I’ve missed anyone out, do feel free to lambast me in comments, it’s your duty.

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• SQL SERVER – PAGELATCH_DT, PAGELATCH_EX, PAGELATCH_KP, PAGELATCH_SH, PAGELATCH_UP – Wait Type – Day 12 of 28

  - by pinaldave

  This is another common wait type. However, I still frequently see people getting confused with PAGEIOLATCH_X and PAGELATCH_X wait types. Actually, there is a big difference between the two. PAGEIOLATCH is related to IO issues, while PAGELATCH is not related to IO issues but is oftentimes linked to a buffer issue. Before we delve deeper in this interesting topic, first let us understand what Latch is. Latches are internal SQL Server locks which can be described as very lightweight and short-term synchronization objects. Latches are not primarily to protect pages being read from disk into memory. It’s a synchronization object for any in-memory access to any portion of a log or data file.[Updated based on comment of Paul Randal] The difference between locks and latches is that locks seal all the involved resources throughout the duration of the transactions (and other processes will have no access to the object), whereas latches locks the resources during the time when the data is changed. This way, a latch is able to maintain the integrity of the data between storage engine and data cache. A latch is a short-living lock that is put on resources on buffer cache and in the physical disk when data is moved in either directions. As soon as the data is moved, the latch is released. Now, let us understand the wait stat type  related to latches. From Book On-Line: PAGELATCH_DT Occurs when a task is waiting on a latch for a buffer that is not in an I/O request. The latch request is in Destroy mode. PAGELATCH_EX Occurs when a task is waiting on a latch for a buffer that is not in an I/O request. The latch request is in Exclusive mode. PAGELATCH_KP Occurs when a task is waiting on a latch for a buffer that is not in an I/O request. The latch request is in Keep mode. PAGELATCH_SH Occurs when a task is waiting on a latch for a buffer that is not in an I/O request. The latch request is in Shared mode. PAGELATCH_UP Occurs when a task is waiting on a latch for a buffer that is not in an I/O request. The latch request is in Update mode. PAGELATCH_X Explanation: When there is a contention of access of the in-memory pages, this wait type shows up. It is quite possible that some of the pages in the memory are of very high demand. For the SQL Server to access them and put a latch on the pages, it will have to wait. This wait type is usually created at the same time. Additionally, it is commonly visible when the TempDB has higher contention as well. If there are indexes that are heavily used, contention can be created as well, leading to this wait type. Reducing PAGELATCH_X wait: The following counters are useful to understand the status of the PAGELATCH: Average Latch Wait Time (ms): The wait time for latch requests that have to wait. Latch Waits/sec: This is the number of latch requests that could not be granted immediately. Total Latch Wait Time (ms): This is the total latch wait time for latch requests in the last second. If there is TempDB contention, I suggest that you read the blog post of Robert Davis right away. He has written an excellent blog post regarding how to find out TempDB contention. The same blog post explains the terms in the allocation of GAM, SGAM and PFS. If there was a TempDB contention, Paul Randal explains the optimal settings for the TempDB in his misconceptions series. Trace Flag 1118 can be useful but use it very carefully. I totally understand that this blog post is not as clear as my other blog posts. I suggest if this wait stats is on one of your higher wait type. Do leave a comment or send me an email and I will get back to you with my solution for your situation. May the looking at all other wait stats and types together become effective as this wait type can help suggest proper bottleneck in your system. Read all the post in the Wait Types and Queue series. Note: The information presented here is from my experience and there is no way that I claim it to be accurate. I suggest reading Book OnLine for further clarification. All the discussions of Wait Stats in this blog are generic and vary from system to system. It is recommended that you test this on a development server before implementing it to a production server. Reference: Pinal Dave (http://blog.SQLAuthority.com)   Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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• F# for the C# Programmer

  - by mbcrump

  Are you a C# Programmer and can’t make it past a day without seeing or hearing someone mention F#?  Today, I’m going to walk you through your first F# application and give you a brief introduction to the language. Sit back this will only take about 20 minutes. Introduction Microsoft's F# programming language is a functional language for the .NET framework that was originally developed at Microsoft Research Cambridge by Don Syme. In October 2007, the senior vice president of the developer division at Microsoft announced that F# was being officially productized to become a fully supported .NET language and professional developers were hired to create a team of around ten people to build the product version. In September 2008, Microsoft released the first Community Technology Preview (CTP), an official beta release, of the F# distribution . In December 2008, Microsoft announced that the success of this CTP had encouraged them to escalate F# and it is now will now be shipped as one of the core languages in Visual Studio 2010 , alongside C++, C# 4.0 and VB. The F# programming language incorporates many state-of-the-art features from programming language research and ossifies them in an industrial strength implementation that promises to revolutionize interactive, parallel and concurrent programming. Advantages of F# F# is the world's first language to combine all of the following features: Type inference: types are inferred by the compiler and generic definitions are created automatically. Algebraic data types: a succinct way to represent trees. Pattern matching: a comprehensible and efficient way to dissect data structures. Active patterns: pattern matching over foreign data structures. Interactive sessions: as easy to use as Python and Mathematica. High performance JIT compilation to native code: as fast as C#. Rich data structures: lists and arrays built into the language with syntactic support. Functional programming: first-class functions and tail calls. Expressive static type system: finds bugs during compilation and provides machine-verified documentation. Sequence expressions: interrogate huge data sets efficiently. Asynchronous workflows: syntactic support for monadic style concurrent programming with cancellations. Industrial-strength IDE support: multithreaded debugging, and graphical throwback of inferred types and documentation. Commerce friendly design and a viable commercial market. Lets try a short program in C# then F# to understand the differences. Using C#: Create a variable and output the value to the console window: Sample Program. using System;   namespace ConsoleApplication9 {     class Program     {         static void Main(string[] args)         {             var a = 2;             Console.WriteLine(a);             Console.ReadLine();         }     } } A breeze right? 14 Lines of code. We could have condensed it a bit by removing the “using” statment and tossing the namespace. But this is the typical C# program. Using F#: Create a variable and output the value to the console window: To start, open Visual Studio 2010 or Visual Studio 2008. Note: If using VS2008, then please download the SDK first before getting started. If you are using VS2010 then you are already setup and ready to go. So, click File-> New Project –> Other Languages –> Visual F# –> Windows –> F# Application. You will get the screen below. Go ahead and enter a name and click OK. Now, you will notice that the Solution Explorer contains the following: Double click the Program.fs and enter the following information. Hit F5 and it should run successfully. Sample Program. open System let a = 2        Console.WriteLine a As Shown below: Hmm, what? F# did the same thing in 3 lines of code. Show me the interactive evaluation that I keep hearing about. The F# development environment for Visual Studio 2010 provides two different modes of execution for F# code: Batch compilation to a .NET executable or DLL. (This was accomplished above). Interactive evaluation. (Demo is below) The interactive session provides a > prompt, requires a double semicolon ;; identifier at the end of a code snippet to force evaluation, and returns the names (if any) and types of resulting definitions and values. To access the F# prompt, in VS2010 Goto View –> Other Window then F# Interactive. Once you have the interactive window type in the following expression: 2+3;; as shown in the screenshot below: I hope this guide helps you get started with the language, please check out the following books for further information. F# Books for further reading   Foundations of F# Author: Robert Pickering An introduction to functional programming with F#. Including many samples, this book walks through the features of the F# language and libraries, and covers many of the .NET Framework features which can be leveraged with F#.       Functional Programming for the Real World: With Examples in F# and C# Authors: Tomas Petricek and Jon Skeet An introduction to functional programming for existing C# developers written by Tomas Petricek and Jon Skeet. This book explains the core principles using both C# and F#, shows how to use functional ideas when designing .NET applications and presents practical examples such as design of domain specific language, development of multi-core applications and programming of reactive applications.

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• Liskov Substitution Principle and the Oft Forgot Third Wheel

  - by Stacy Vicknair

  Liskov Substitution Principle (LSP) is a principle of object oriented programming that many might be familiar with from the SOLID principles mnemonic from Uncle Bob Martin. The principle highlights the relationship between a type and its subtypes, and, according to Wikipedia, is defined by Barbara Liskov and Jeanette Wing as the following principle:   Let be a property provable about objects of type . Then should be provable for objects of type where is a subtype of .   Rectangles gonna rectangulate The iconic example of this principle is illustrated with the relationship between a rectangle and a square. Let’s say we have a class named Rectangle that had a property to set width and a property to set its height. 1: Public Class Rectangle 2: Overridable Property Width As Integer 3: Overridable Property Height As Integer 4: End Class   We all at some point here that inheritance mocks an “IS A” relationship, and by gosh we all know square IS A rectangle. So let’s make a square class that inherits from rectangle. However, squares do maintain the same length on every side, so let’s override and add that behavior. 1: Public Class Square 2: Inherits Rectangle 3:  4: Private _sideLength As Integer 5:  6: Public Overrides Property Width As Integer 7: Get 8: Return _sideLength 9: End Get 10: Set(value As Integer) 11: _sideLength = value 12: End Set 13: End Property 14:  15: Public Overrides Property Height As Integer 16: Get 17: Return _sideLength 18: End Get 19: Set(value As Integer) 20: _sideLength = value 21: End Set 22: End Property 23: End Class   Now, say we had the following test: 1: Public Sub SetHeight_DoesNotAffectWidth(rectangle As Rectangle) 2: 'arrange 3: Dim expectedWidth = 4 4: rectangle.Width = 4 5:  6: 'act 7: rectangle.Height = 7 8:  9: 'assert 10: Assert.AreEqual(expectedWidth, rectangle.Width) 11: End Sub   If we pass in a rectangle, this test passes just fine. What if we pass in a square?   This is where we see the violation of Liskov’s Principle! A square might "IS A” to a rectangle, but we have differing expectations on how a rectangle should function than how a square should! Great expectations Here’s where we pat ourselves on the back and take a victory lap around the office and tell everyone about how we understand LSP like a boss. And all is good… until we start trying to apply it to our work. If I can’t even change functionality on a simple setter without breaking the expectations on a parent class, what can I do with subtyping? Did Liskov just tell me to never touch subtyping again? The short answer: NO, SHE DIDN’T. When I first learned LSP, and from those I’ve talked with as well, I overlooked a very important but not appropriately stressed quality of the principle: our expectations. Our inclination is to want a logical catch-all, where we can easily apply this principle and wipe our hands, drop the mic and exit stage left. That’s not the case because in every different programming scenario, our expectations of the parent class or type will be different. We have to set reasonable expectations on the behaviors that we expect out of the parent, then make sure that those expectations are met by the child. Any expectations not explicitly expected of the parent aren’t expected of the child either, and don’t register as a violation of LSP that prevents implementation. You can see the flexibility mentioned in the Wikipedia article itself: A typical example that violates LSP is a Square class that derives from a Rectangle class, assuming getter and setter methods exist for both width and height. The Square class always assumes that the width is equal with the height. If a Square object is used in a context where a Rectangle is expected, unexpected behavior may occur because the dimensions of a Square cannot (or rather should not) be modified independently. This problem cannot be easily fixed: if we can modify the setter methods in the Square class so that they preserve the Square invariant (i.e., keep the dimensions equal), then these methods will weaken (violate) the postconditions for the Rectangle setters, which state that dimensions can be modified independently. Violations of LSP, like this one, may or may not be a problem in practice, depending on the postconditions or invariants that are actually expected by the code that uses classes violating LSP. Mutability is a key issue here. If Square and Rectangle had only getter methods (i.e., they were immutable objects), then no violation of LSP could occur. What this means is that the above situation with a rectangle and a square can be acceptable if we do not have the expectation for width to leave height unaffected, or vice-versa, in our application. Conclusion – the oft forgot third wheel Liskov Substitution Principle is meant to act as a guidance and warn us against unexpected behaviors. Objects can be stateful and as a result we can end up with unexpected situations if we don’t code carefully. Specifically when subclassing, make sure that the subclass meets the expectations held to its parent. Don’t let LSP think you cannot deviate from the behaviors of the parent, but understand that LSP is meant to highlight the importance of not only the parent and the child class, but also of the expectations WE set for the parent class and the necessity of meeting those expectations in order to help prevent sticky situations.   Code examples, in both VB and C# Technorati Tags: LSV,Liskov Substitution Principle,Uncle Bob,Robert Martin,Barbara Liskov,Liskov

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• XNA Notes 002

  - by George Clingerman

  This past week (much like every week in the XNA community) was filled with things happening and people doing cool things (and getting noticed for doing cool things!). You can definitely tell there are some Xbox LIVE Indie game developers starting to make some names for themselves. Can’t wait to name drop them at bars. Me- “Oh you played Game X? Yeah, I know the guy that made that. Pretty cool guy.” Yeah, I’ll be THAT guy.   Time Critical XNA News 30 days left to submit XBLIGs made in XNA Game Studio 3.1 http://blogs.msdn.com/b/xna/archive/2011/01/08/30-days-left-to-submit-xna-gs-3-1-games-to-app-hub.aspx Jeromy Walsh wants you to know his XNA 4.0 Winter Workshop starting soon, go get signed up! And the forum is now LIVE on GameDev.net http://gamedevelopedia.com/ http://tinyurl.com/4gg2cfv The XNA Team Per Nick Gravelyn, Aaron Stebner’s blog post is a must read for icons on Windows Phone http://forums.create.msdn.com/forums/p/72022/439597.aspx#439597 http://blogs.msdn.com/b/astebner/archive/2010/10/01/10070507.aspx Shawn Hargreaves writes about Sprite Billboards in a 3D world http://blogs.msdn.com/b/shawnhar/archive/2011/01/12/spritebatch-billboards-in-a-3d-world.aspx XNA MVPs Andy “The ZMan” Dunn wants YOU to come to the MVP Summit and run a 5K http://www.indiegameguy.com/blogs/zman/archive/2010/12/26/come-to-the-mvp-summit-and-run-a-5k-yes-you.aspx Jim Perry updates his forum signature just to make it clear that he’s not speaking for Microsoft or giving official information (LOL, thanks Jim, now if only people will take the time to read that...) XNA MVP | Please use the Forum Search and read the Forum FAQs | My posts are not official info http://forums.create.msdn.com/forums/p/70849/439613.aspx#439613 XNA Developers Robert Boyd (@werezombie) working hard at converting his RPG engine used to make Breath of Death VII and Chtulu Saves the World to XNA 4.0. If you haven’t done the upgrade yet yourself, might be useful to read back through his tweets and recent forum posts to see the problems/solutions he’s encountered. http://forums.create.msdn.com/forums/p/71834/438099.aspx#438099 http://www.twitter.com/werezompire SpynDoctorGames is in the final phase before the release of Your Doodles are Bugged for the PC! Going to be interesting to watch as more XNA game developers explore the PC game market for their games. http://twitter.com/SpynDoctorGames/statuses/24503173217521664 http://www.spyn-doctor.de @DrMistry shares some details of his next title YoYoYo http://www.mstargames.co.uk/mistryblogmain/35-genblog/177-a-new-year-a-new-game-and-maybe-a-new-approach.html Travis Woodward (@RabidLionGames) has a blog post coming this weekend on Farseer and Mario-like platformer movement. http://twitter.com/RabidLionGames/statuses/24992762021548032 http://www.rabidlion.com/ S4G Interview with Radiangames http://n4g.com/news/679492/s4g-interview-with-radiangames XBLAratings.com interviews Steve Flores (@DragonDivide) developer of Alpha Squad http://www.xblaratings.com/developer-qaa/3621-alpha-squad-developer-interview XBox LIVE Indie Games If you haven’t been reading the roundups on IndieGames by NaviFairy on GayGamer, you’ve been missing out! http://gaygamer.net/2011/01/xbox_indie_review_roundup_1112.html Armless Octopus posts the Top 20 Games of 2010 Part 1 http://www.armlessoctopus.com/2011/01/10/top-20-xbox-live-indie-games-of-2010-part-1/ Armless Octopus posts the Top 20 Games of 2010 Part 2 http://www.armlessoctopus.com/2011/01/12/top-20-xbox-live-indie-games-of-2010-%E2%80%93-part-2/ Xbox LIVE Indie Game Reviews http://www.gamemarx.com/ Don’t forget to be following @XboxHornet . That’s a great way to snag free copies of Xbox LIVE Indie Games http://twitter.com/XboxHornet/statuses/24471103808208896 http://www.xboxhornet.com/wordpress/ Xbox LIVE Indie Game Review posts the top 20 Xbox 360 LIVE Indie Games of 2010 http://www.xbox-360-community-games-reviews.com/top-20-best-xbox-360-live-indie-games-of-2010/ VVGtv to Stream #XBLIG Again! Help out if you can. http://vvgtv.com/2011/01/07/vvgtv-to-stream-xblig-again/ Indie Gamer Magazine Issue 14 has a look at the Xbox LIVE Winter Indie Game Uprisiing http://www.indiegamemag.com/issue14/ XNA Game Development Andrew Russell announced and asked for help in his development of ExEn: XNA for iPhone, Android and Silverlight http://rockethub.com/projects/752-exen-xna-for-iphone-android-and-silverlight App Hub forums letting you down? Don’t forget about StackOverflow and the game development specific version gamedev.stackexchange http://stackoverflow.com/questions/tagged/xna http://gamedev.stackexchange.com/questions/tagged/xna Transmute gets an update from Aaron Foley (@slyprid) and you can now add and visually edit parallax layers to your 2D tile game. http://twitpic.com/3nudj0 http://twitter.com/slyprid/statuses/23418379574448128 http://forgottenstarstudios.com/Transmute/default.html Webcomics Weekly #75 touches on some feelings I’ve seen people try to express (myself included) when talking about game development and what types of games should be released for XBLIG http://www.pvponline.com/2011/01/05/webcomics-weekly-75-sour-oats/ Setting up a new PC for XNA development? Here’s a site that helps you quickly build a installer for all the most common applications developers use. http://ninite.com/ Fun wew thread on the XNA forums asking XBLIG/XNA developers just what their Top 10 favorite video games of all time are. http://forums.create.msdn.com/forums/107.aspx Christopher Hill (@Xalterax) stumbled across an entire community that does nothing but create box art. This is a great potential resource for Xbox LIVE Indie Game developers to get some awesome box art for their games. http://forums.create.msdn.com/forums/p/46582/441451.aspx#441451 http://www.vgboxart.com/browse/plat/360/ Don’t forget about the XNA Wiki, fantastic community resource (and roll up those sleeves and contribute already!) http://xnawiki.com/index.php?title=Main_Page

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• Scripting out Contained Database Users

  - by Argenis

    Today’s blog post comes from a Twitter thread on which @SQLSoldier, @sqlstudent144 and @SQLTaiob were discussing the internals of contained database users. Unless you have been living under a rock, you’ve heard about the concept of contained users within a SQL Server database (hit the link if you have not). In this article I’d like to show you that you can, indeed, script out contained database users and recreate them on another database, as either contained users or as good old fashioned logins/server principals as well. Why would this be useful? Well, because you would not need to know the password for the user in order to recreate it on another instance. I know there is a limited number of scenarios where this would be necessary, but nonetheless I figured I’d throw this blog post to show how it can be done. A more obscure use case: with the password hash (which I’m about to show you how to obtain) you could also crack the password using a utility like hashcat, as highlighted on this SQLServerCentral article. The Investigation SQL Server uses System Base Tables to save the password hashes of logins and contained database users. For logins it uses sys.sysxlgns, whereas for contained database users it leverages sys.sysowners. I’ll show you what I do to figure this stuff out: I create a login/contained user, and then I immediately browse the transaction log with, for example, fn_dblog. It’s pretty obvious that only two base tables touched by the operation are sys.sysxlgns, and also sys.sysprivs – the latter is used to track permissions. If I connect to the DAC on my instance, I can query for the password hash of this login I’ve just created. A few interesting things about this hash. This was taken on my laptop, and I happen to be running SQL Server 2014 RTM CU2, which is the latest public build of SQL Server 2014 as of time of writing. In 2008 R2 and prior versions (back to 2000), the password hashes would start with 0x0100. The reason why this changed is because starting with SQL Server 2012 password hashes are kept using a SHA512 algorithm, as opposed to SHA-1 (used since 2000) or Snefru (used in 6.5 and 7.0). SHA-1 is nowadays deemed unsafe and is very easy to crack. For regular SQL logins, this information is exposed through the sys.sql_logins catalog view, so there is really no need to connect to the DAC to grab an SID/password hash pair. For contained database users, there is (currently) no method of obtaining SID or password hashes without connecting to the DAC. If we create a contained database user, this is what we get from the transaction log: Note that the System Base Table used in this case is sys.sysowners. sys.sysprivs is used as well, and again this is to track permissions. To query sys.sysowners, you would have to connect to the DAC, as I mentioned previously. And this is what you would get: There are other ways to figure out what SQL Server uses under the hood to store contained database user password hashes, like looking at the execution plan for a query to sys.dm_db_uncontained_entities (Thanks, Robert Davis!) SIDs, Logins, Contained Users, and Why You Care…Or Not. One of the reasons behind the existence of Contained Users was the concept of portability of databases: it is really painful to maintain Server Principals (Logins) synced across most shared-nothing SQL Server HA/DR technologies (Mirroring, Availability Groups, and Log Shipping). Often times you would need the Security Identifier (SID) of these logins to match across instances, and that meant that you had to fetch whatever SID was assigned to the login on the principal instance so you could recreate it on a secondary. With contained users you normally wouldn’t care about SIDs, as the users are always available (and synced, as long as synchronization takes place) across instances. Now you might be presented some particular requirement that might specify that SIDs synced between logins on certain instances and contained database users on other databases. How would you go about creating a contained database user with a specific SID? The answer is that you can’t do it directly, but there’s a little trick that would allow you to do it. Create a login with a specified SID and password hash, create a user for that server principal on a partially contained database, then migrate that user to contained using the system stored procedure sp_user_migrate_to_contained, then drop the login. CREATE LOGIN <login_name> WITH PASSWORD = <password_hash> HASHED, SID = <sid> ; GO USE <partially_contained_db>; GO CREATE USER <user_name> FROM LOGIN <login_name>; GO EXEC sp_migrate_user_to_contained @username = <user_name>, @rename = N’keep_name’, @disablelogin = N‘disable_login’; GO DROP LOGIN <login_name>; GO Here’s how this skeleton would look like in action: And now I have a contained user with a specified SID and password hash. In my example above, I renamed the user after migrated it to contained so that it is, hopefully, easier to understand. Enjoy!

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• Oracle Social Network Developer Challenge Winners

  - by kellsey.ruppel

  Originally posted by Jake Kuramoto on The Apps Lab blog. Now that OpenWorld 2012 has wrapped, I have time to tell you all about what happened. Maybe you recall that Noel (@noelportugal) and I were running a modified hackathon during the show, the Oracle Social Network Developer Challenge. Without further ado, congratulations to Dimitri Gielis (@dgielis) and Martin Giffy D’Souza (@martindsouza) on their winning entry, an integration between Oracle APEX and Oracle Social Network that integrates feedback and bug submission with Oracle Social Network Conversations, allowing developers, end-users and project leaders to view and discuss the feedback on their APEX applications from within Oracle Social Network. Update: Bob Rhubart of OTN (@brhubart) interviewed Dimitri and Martin right after their big win. Money quote from Dimitri when asked what he’d buy with the $500 in Amazon gift cards, “Oracle Social Network.” Nice one. In their own words: In the developers perspective it’s important to get feedback soon, so after a first iteration and end-users start to test, they can give feedback of the application. Previously it stopped there, and it was up to the developer to communicate further with email, phone etc. With OSN every feedback and communication gets logged and other people can see the discussion immediately as well. For the end users perspective he can now communicate in a more efficient way to not only the developers, but also between themselves. Maybe many end-users (in different locations) would like to change some behaviour, by using OSN they can see the entry somebody put in with a screenshot and they can just start to chat about it. Some key technical end users can have lighten the tasks of the development team by looking at the feedback first and start to communicate with their peers. For the project manager he has now the ability to really see what communication has taken place in certain areas and can make decisions on that. Later, if things come up again, he can always go back in OSN and see what was said at that moment in time. Integrating OSN in the APEX applications enhances the user experience, makes the lives of the developers easier and gives a better overview to project managers. Incidentally, you may already know Dimitri and Martin, since both are Oracle Ace Directors. I ran into Martin at the Ace Director briefings Friday before the conference started, and at that point, he wasn’t sure he’d have time to enter the Challenge. After some coaxing, he and Dimitri agreed to give it a go and banged out their entry on Tuesday night, or more accurately, very early Wednesday morning, the day of the Challenge judging. I think they said it took them about four hours of hardcore coding to get it done, very much like a traditional hackathon, which is essentially a code sprint from idea to finished product. Here are some screenshots of the workflow they built. #gallery-1 { margin: auto; } #gallery-1 .gallery-item { float: left; margin-top: 10px; text-align: center; width: 33%; } #gallery-1 img { border: 2px solid #cfcfcf; } #gallery-1 .gallery-caption { margin-left: 0; } I love this idea, i.e. closing the loop between web developers and users, a very common pain point, and so did our judges. Speaking of, special thanks to our panel of three judges: Reggie Bradford (@reggiebradford), serial entrepreneur, founder of Vitrue and SVP of Cloud Product Development at Oracle Robert Hipps (@roberthipps), VP of Development for Oracle Social Network and my former boss Roland Smart (@rsmartx), VP of Social Marketing and the brains behind the Oracle Social Developer Community Finally, thanks to everyone who made this possible, including: The three other teams from HarQen (@harqen), TEAM Informatics (@teaminformatics) and Fishbowl Solutions (@fishbowle20) featuring Friend of the ‘Lab John Sim (@jrsim_uix), who finished and presented entries. I’ll be posting the details of their work this week. The one guy who finished an entry, but couldn’t make the judging, Bex Huff (@bex). Bex rallied from a hospitalization due to an allergic reaction during the show; he’s fine, don’t worry. I’ll post details of his work next week, too. The 40-plus people who registered to compete in the Challenge. Noel for all his hard work, sample code, and flying monkey target, more on that to come. The Oracle Social Network development team for supporting this event. Everyone in legal and the beta program office for their help. And finally, the Oracle Technology Network (@oracletechnet) for hosting the event and providing countless hours of operational and moral support. Sorry if I’ve missed some people, since this was a huge team effort. This event was a big success, and we plan to do similar events in the future. Stay tuned to this channel for more. 

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• How to Use Steam In-Home Streaming

  - by Chris Hoffman

  Steam’s In-Home Streaming is now available to everyone, allowing you to stream PC games from one PC to another PC on the same local network. Use your gaming PC to power your laptops and home theater system. This feature doesn’t allow you to stream games over the Internet, only the same local network. Even if you tricked Steam, you probably wouldn’t get good streaming performance over the Internet. Why Stream? When you use Steam In-Home streaming, one PC sends its video and audio to another PC. The other PC views the video and audio like it’s watching a movie, sending back mouse, keyboard, and controller input to the other PC. This allows you to have a fast gaming PC power your gaming experience on slower PCs. For example, you could play graphically demanding games on a laptop in another room of your house, even if that laptop has slower integrated graphics. You could connect a slower PC to your television and use your gaming PC without hauling it into a different room in your house. Streaming also enables cross-platform compatibility. You could have a Windows gaming PC and stream games to a Mac or Linux system. This will be Valve’s official solution for compatibility with old Windows-only games on the Linux (Steam OS) Steam Machines arriving later this year. NVIDIA offers their own game streaming solution, but it requires certain NVIDIA graphics hardware and can only stream to an NVIDIA Shield device. How to Get Started In-Home Streaming is simple to use and doesn’t require any complex configuration — or any configuration, really. First, log into the Steam program on a Windows PC. This should ideally be a powerful gaming PC with a powerful CPU and fast graphics hardware. Install the games you want to stream if you haven’t already — you’ll be streaming from your PC, not from Valve’s servers. (Valve will eventually allow you to stream games from Mac OS X, Linux, and Steam OS systems, but that feature isn’t yet available. You can still stream games to these other operating systems.) Next, log into Steam on another computer on the same network with the same Steam username. Both computers have to be on the same subnet of the same local network. You’ll see the games installed on your other PC in the Steam client’s library. Click the Stream button to start streaming a game from your other PC. The game will launch on your host PC, and it will send its audio and video to the PC in front of you. Your input on the client will be sent back to the server. Be sure to update Steam on both computers if you don’t see this feature. Use the Steam > Check for Updates option within Steam and install the latest update. Updating to the latest graphics drivers for your computer’s hardware is always a good idea, too. Improving Performance Here’s what Valve recommends for good streaming performance: Host PC: A quad-core CPU for the computer running the game, minimum. The computer needs enough processor power to run the game, compress the video and audio, and send it over the network with low latency. Streaming Client: A GPU that supports hardware-accelerated H.264 decoding on the client PC. This hardware is included on all recent laptops and PCs. Ifyou have an older PC or netbook, it may not be able to decode the video stream quickly enough. Network Hardware: A wired network connection is ideal. You may have success with wireless N or AC networks with good signals, but this isn’t guaranteed. Game Settings: While streaming a game, visit the game’s setting screen and lower the resolution or turn off VSync to speed things up. In-Home Steaming Settings: On the host PC, click Steam > Settings and select In-Home Streaming to view the In-Home Streaming settings. You can modify your streaming settings to improve performance and reduce latency. Feel free to experiment with the options here and see how they affect performance — they should be self-explanatory. Check Valve’s In-Home Streaming documentation for troubleshooting information. You can also try streaming non-Steam games. Click Games > Add a Non-Steam Game to My Library on your host PC and add a PC game you have installed elsewhere on your system. You can then try streaming it from your client PC. Valve says this “may work but is not officially supported.” Image Credit: Robert Couse-Baker on Flickr, Milestoned on Flickr

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