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• Oracle's Global Single Schema

  - by david.butler(at)oracle.com

  Maximizing business process efficiencies in a heterogeneous environment is very difficult. The difficulty stems from the fact that the various applications across the Information Technology (IT) landscape employ different integration standards, different message passing strategies, and different workflow engines. Vendors such as Oracle and others are delivering tools to help IT organizations manage the complexities introduced by these differences. But the one remaining intractable problem impacting efficient operations is the fact that these applications have different definitions for the same business data. Business data is your business information codified for computer programs to use. A good data model will represent the way your organization does business. The computer applications your organization deploys to improve operational efficiency are built to operate on the business data organized into this schema.  If the schema does not represent how you do business, the applications on that schema cannot provide the features you need to achieve the desired efficiencies. Business processes span these applications. Data problems break these processes rendering them far less efficient than they need to be to achieve organization goals. Thus, the expected return on the investment in these applications is never realized. The success of all business processes depends on the availability of accurate master data.  Clearly, the solution to this problem is to consolidate all the master data an organization uses to run its business. Then clean it up, augment it, govern it, and connect it back to the applications that need it. Until now, this obvious solution has been difficult to achieve because no one had defined a data model sufficiently broad, deep and flexible enough to support transaction processing on all key business entities and serve as a master superset to all other operational data models deployed in heterogeneous IT environments. Today, the situation has changed. Oracle has created an operational data model (aka schema) that can support accurate and consistent master data across heterogeneous IT systems. This is foundational for providing a way to consolidate and integrate master data without having to replace investments in existing applications. This Global Single Schema (GSS) represents a revolutionary breakthrough that allows for true master data consolidation. Oracle has deep knowledge of applications dating back to the early 1990s.  It developed applications in the areas of Supply Chain Management (SCM), Product Lifecycle Management (PLM), Enterprise Resource Planning (ERP), Customer Relationship Management (CRM), Human Capital Management (HCM), Financials and Manufacturing. In addition, Oracle applications were delivered for key industries such as Communications, Financial Services, Retail, Public Sector, High Tech Manufacturing (HTM) and more. Expertise in all these areas drove requirements for GSS. The following figure illustrates Oracle's unique position that enabled the creation of the Global Single Schema. GSS Requirements Gathering GSS defines all the key business entities and attributes including Customers, Contacts, Suppliers, Accounts, Products, Services, Materials, Employees, Installed Base, Sites, Assets, and Inventory to name just a few. In addition, Oracle delivers GSS pre-integrated with a wide variety of operational applications.  Business Process Automation EBusiness is about maximizing operational efficiency. At the highest level, these 'operations' span all that you do as an organization.  The following figure illustrates some of these high-level business processes. Enterprise Business Processes Supplies are procured. Assets are maintained. Materials are stored. Inventory is accumulated. Products and Services are engineered, produced and sold. Customers are serviced. And across this entire spectrum, Employees do the procuring, supporting, engineering, producing, selling and servicing. Not shown, but not to be overlooked, are the accounting and the financial processes associated with all this procuring, manufacturing, and selling activity. Supporting all these applications is the master data. When this data is fragmented and inconsistent, the business processes fail and inefficiencies multiply. But imagine having all the data under these operational business processes in one place. ·            The same accurate and timely customer data will be provided to all your operational applications from the call center to the point of sale. ·            The same accurate and timely supplier data will be provided to all your operational applications from supply chain planning to procurement. ·            The same accurate and timely product information will be available to all your operational applications from demand chain planning to marketing. You would have a single version of the truth about your assets, financial information, customers, suppliers, employees, products and services to support your business automation processes as they flow across your business applications. All company and partner personnel will access the same exact data entity across all your channels and across all your lines of business. Oracle's Global Single Schema enables this vision of a single version of the truth across the heterogeneous operational applications supporting the entire enterprise. Global Single Schema Oracle's Global Single Schema organizes hundreds of thousands of attributes into 165 major schema objects supporting over 180 business application modules. It is designed for international operations, and extensibility.  The schema is delivered with a full set of public Application Programming Interfaces (APIs) and an Integration Repository with modern Service Oriented Architecture interfaces to make data available as a services (DaaS) to business processes and enable operations in heterogeneous IT environments. ·         Key tables can be extended with unlimited numbers of additional attributes and attribute groups for maximum flexibility.  o    This enables model extensions that reflect business entities unique to your organization's operations. ·         The schema is multi-organization enabled so data manipulation can be controlled along organizational boundaries. ·         It uses variable byte Unicode to support over 31 languages. ·         The schema encodes flexible date and flexible address formats for easy localizations. No matter how complex your business is, Oracle's Global Single Schema can hold your business objects and support your global operations. Oracle's Global Single Schema identifies and defines the business objects an enterprise needs within the context of its business operations. The interrelationships between the business objects are also contained within the GSS data model. Their presence expresses fundamental business rules for the interaction between business entities. The following figure illustrates some of these connections.   Interconnected Business Entities Interconnecte business processes require interconnected business data. No other MDM vendor has this capability. Everyone else has either one entity they can master or separate disconnected models for various business entities. Higher level integrations are made available, but that is a weak architectural alternative to data level integration in this critically important aspect of Master Data Management.    

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• SQL SERVER – Using expressor Composite Types to Enforce Business Rules

  - by pinaldave

  One of the features that distinguish the expressor Data Integration Platform from other products in the data integration space is its concept of composite types, which provide an effective and easily reusable way to clearly define the structure and characteristics of data within your application.  An important feature of the composite type approach is that it allows you to easily adjust the content of a record to its ultimate purpose.  For example, a record used to update a row in a database table is easily defined to include only the minimum set of columns, that is, a value for the key column and values for only those columns that need to be updated. Much like a class in higher level programming languages, you can also use the composite type as a way to enforce business rules onto your data by encapsulating a datum’s name, data type, and constraints (for example, maximum, minimum, or acceptable values) as a single entity, which ensures that your data can not assume an invalid value.  To what extent you use this functionality is a decision you make when designing your application; the expressor design paradigm does not force this approach on you. Let’s take a look at how these features are used.  Suppose you want to create a group of applications that maintain the employee table in your human resources database. Your table might have a structure similar to the HumanResources.Employee table in the AdventureWorks database.  This table includes two columns, EmployeID and rowguid, that are maintained by the relational database management system; you cannot provide values for these columns when inserting new rows into the table. Additionally, there are columns such as VacationHours and SickLeaveHours that you might choose to update for all employees on a monthly basis, which justifies creation of a dedicated application. By creating distinct composite types for the read, insert and update operations against this table, you can more easily manage this table’s content. When developing this application within expressor Studio, your first task is to create a schema artifact for the database table.  This process is completely driven by a wizard, only requiring that you select the desired database schema and table.  The resulting schema artifact defines the mapping of result set records to a record within the expressor data integration application.  The structure of the record within the expressor application is a composite type that is given the default name CompositeType1.  As you can see in the following figure, all columns from the table are included in the result set and mapped to an identically named attribute in the default composite type. If you are developing an application that needs to read this table, perhaps to prepare a year-end report of employees by department, you would probably not be interested in the data in the rowguid and ModifiedDate columns.  A typical approach would be to drop this unwanted data in a downstream operator.  But using an alternative composite type provides a better approach in which the unwanted data never enters your application. While working in expressor  Studio’s schema editor, simply create a second composite type within the same schema artifact, which you could name ReadTable, and remove the attributes corresponding to the unwanted columns. The value of an alternative composite type is even more apparent when you want to insert into or update the table.  In the composite type used to insert rows, remove the attributes corresponding to the EmployeeID primary key and rowguid uniqueidentifier columns since these values are provided by the relational database management system. And to update just the VacationHours and SickLeaveHours columns, use a composite type that includes only the attributes corresponding to the EmployeeID, VacationHours, SickLeaveHours and ModifiedDate columns. By specifying this schema artifact and composite type in a Write Table operator, your upstream application need only deal with the four required attributes and there is no risk of unintentionally overwriting a value in a column that does not need to be updated. Now, what about the option to use the composite type to enforce business rules?  If you review the composition of the default composite type CompositeType1, you will note that the constraints defined for many of the attributes mirror the table column specifications.  For example, the maximum number of characters in the NationaIDNumber, LoginID and Title attributes is equivalent to the maximum width of the target column, and the size of the MaritalStatus and Gender attributes is limited to a single character as required by the table column definition.  If your application code leads to a violation of these constraints, an error will be raised.  The expressor design paradigm then allows you to handle the error in a way suitable for your application.  For example, a string value could be truncated or a numeric value could be rounded. Moreover, you have the option of specifying additional constraints that support business rules unrelated to the table definition. Let’s assume that the only acceptable values for marital status are S, M, and D.  Within the schema editor, double-click on the MaritalStatus attribute to open the Edit Attribute window.  Then click the Allowed Values checkbox and enter the acceptable values into the Constraint Value text box. The schema editor is updated accordingly. There is one more option that the expressor semantic type paradigm supports.  Since the MaritalStatus attribute now clearly specifies how this type of information should be represented (a single character limited to S, M or D), you can convert this attribute definition into a shared type, which will allow you to quickly incorporate this definition into another composite type or into the description of an output record from a transform operator. Again, double-click on the MaritalStatus attribute and in the Edit Attribute window, click Convert, which opens the Share Local Semantic Type window that you use to name this shared type.  There’s no requirement that you give the shared type the same name as the attribute from which it was derived.  You should supply a name that makes it obvious what the shared type represents. In this posting, I’ve overviewed the expressor semantic type paradigm and shown how it can be used to make your application development process more productive.  The beauty of this feature is that you choose when and to what extent you utilize the functionality, but I’m certain that if you opt to follow this approach your efforts will become more efficient and your work will progress more quickly.  As always, I encourage you to download and evaluate expressor Studio for your current and future data integration needs. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: CodeProject, Pinal Dave, PostADay, SQL, SQL Authority, SQL Documentation, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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• Becoming A Great Developer

  - by Lee Brandt

  Image via Wikipedia I’ve been doing the whole programming thing for awhile and reading and watching some of the best in the business. I have come to notice that the really great developers do a few things that (I think) makes them great. Now don’t get me wrong, I am not saying that I am one of these few. I still struggle with doing some of the things that makes one great at development. Coincidently, many of these things also make you a better person period. Believe That Guidance Is Better Than Answers This is one I have no problem with. I prefer guidance any time I am learning from another developer. Answers may get you going, but guidance will leave you stranded. At some point, you will come across a problem that can only be solved by thinking for yourself and this is where that guidance will really come in handy. You can use that guidance and extrapolate whatever technology to salve that problem (if it’s the right tool for solving that problem). The problem is, lots of developers simply want someone to tell them, “Do this, then this, then set that, and write this.” Favor thinking and learn the guidance of doing X and don’t ask someone to show you how to do X, if that makes sense. Read, Read and Read If you don’t like reading, you’re probably NOT going to make it into the Great Developer group. Great developers read books, they read magazines and they read code. Open source playgrounds like SourceForge, CodePlex and GitHub, have made it extremely easy to download code from developers you admire and see how they do stuff. Chances are, if you read their blog too, they’ll even explain WHY they did what they did (see “Guidance” above). MSDN and Code Magazine have not only code samples, but explanations of how to use certain technologies and sometimes even when NOT to use that same technology. Books are also out on just about every topic. I still favor the less technology centric books. For instance, I generally don’t buy books like, “Getting Started with Jiminy Jappets”. I look for titles like, “How To Write More Effective Code” (again, see guidance). The Addison-Wesley Signature Series is a great example of these types of books. They teach technology-agnostic concepts. Head First Design Patterns is another great guidance book. It teaches the "Gang Of Four" Design Patterns in a very easy-to-understand, picture-heavy way (I LIKE pictures). Hang Your Balls Out There Even though the advice came from a 3rd-shift Kinko’s attendant, doesn’t mean it’s not sound advice. Write some code and put it out for others to read, criticize and castigate you for. Understand that there are some real jerks out there who are absolute geniuses. Don’t be afraid to get some great advice wrapped in some really nasty language. Try to take what’s good about it and leave what’s not. I have a tough time with this myself. I don’t really have any code out there that is available for review (other than my demo code). It takes some guts to do, but in the end, there is no substitute for getting a community of developers to critique your code and give you ways to improve. Get Involved Speaking of community, the local and online user groups and discussion forums are a great place to hear about technologies and techniques you might never come across otherwise. Mostly because you might not know to look. But, once you sit down with a bunch of other developers and start discussing what you’re interested in, you may open up a whole new perspective on it. Don’t just go to the UG meetings and watch the presentations either, get out there and talk, socialize. I realize geeks weren’t meant to necessarily be social creatures, but if you’re amongst other geeks, it’s much easier. I’ve learned more in the last 3-4 years that I have been involved in the community that I did in my previous 8 years of coding without it. Socializing works, even if socialism doesn’t. Continuous Improvement Lean proponents might call this “Kaizen”, but I call it progress. We all know, especially in the technology realm, if you’re not moving ahead, you’re falling behind. It may seem like drinking from a fire hose, but step back and pick out the technologies that speak to you. The ones that may you’re little heart go pitter-patter. Concentrate on those. If you’re still overloaded, pick the best of the best. Just know that if you’re not looking at the code you wrote last week or at least last year with some embarrassment, you’re probably stagnating. That’s about all I can say about that, cause I am all out of clichés to throw at it. :0) Write Code Great painters paint, great writers write, and great developers write code. The most sure-fire way to improve your coding ability is to continue writing code. Don’t just write code that your work throws on you, pick that technology you love or are curious to know more about and walk through some blog demo examples. Take the language you use everyday and try to get it to do something crazy. Who knows, you might create the next Google search algorithm! All in all, being a great developer is about finding yourself in all this code. If it is just a job to you, you will probably never be one of the “Great Developers”, but you’re probably okay with that. If, on the other hand, you do aspire to greatness, get out there and GET it. No one’s going hand it to you.

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• Using a Predicate as a key to a Dictionary

  - by Tom Hines

  I really love Linq and Lambda Expressions in C#.  I also love certain community forums and programming websites like DaniWeb. A user on DaniWeb posted a question about comparing the results of a game that is like poker (5-card stud), but is played with dice. The question stemmed around determining what was the winning hand.  I looked at the question and issued some comments and suggestions toward a potential answer, but I thought it was a neat homework exercise. [A little explanation] I eventually realized not only could I compare the results of the hands (by name) with a certain construct – I could also compare the values of the individual dice with the same construct. That piece of code eventually became a Dictionary with the KEY as a Predicate<int> and the Value a Func<T> that returns a string from the another structure that contains the mapping of an ENUM to a string.  In one instance, that string is the name of the hand and in another instance, it is a string (CSV) representation of of the digits in the hand. An added benefit is that the digits re returned in the order they would be for a proper poker hand.  For instance the hand 1,2,5,3,1 would be returned as ONE_PAIR (1,1,5,3,2). [Getting to the point] 1: using System; 2: using System.Collections.Generic; 3:   4: namespace DicePoker 5: { 6: using KVP_E2S = KeyValuePair<CDicePoker.E_DICE_POKER_HAND_VAL, string>; 7: public partial class CDicePoker 8: { 9: /// <summary> 10: /// Magical construction to determine the winner of given hand Key/Value. 11: /// </summary> 12: private static Dictionary<Predicate<int>, Func<List<KVP_E2S>, string>> 13: map_prd2fn = new Dictionary<Predicate<int>, Func<List<KVP_E2S>, string>> 14: { 15: {new Predicate<int>(i => i.Equals(0)), PlayerTie},//first tie 16:   17: {new Predicate<int>(i => i > 0), 18: (m => string.Format("Player One wins\n1={0}({1})\n2={2}({3})", 19: m[0].Key, m[0].Value, m[1].Key, m[1].Value))}, 20:   21: {new Predicate<int>(i => i < 0), 22: (m => string.Format("Player Two wins\n2={2}({3})\n1={0}({1})", 23: m[0].Key, m[0].Value, m[1].Key, m[1].Value))}, 24:   25: {new Predicate<int>(i => i.Equals(0)), 26: (m => string.Format("Tie({0}) \n1={1}\n2={2}", 27: m[0].Key, m[0].Value, m[1].Value))} 28: }; 29: } 30: } When this is called, the code calls the Invoke method of the predicate to return a bool.  The first on matching true will have its value invoked. 1: private static Func<DICE_HAND, E_DICE_POKER_HAND_VAL> GetHandEval = dh => 2: map_dph2fn[map_dph2fn.Keys.Where(enm2fn => enm2fn(dh)).First()]; After coming up with this process, I realized (with a little modification) it could be called to evaluate the individual values in the dice hand in the event of a tie. 1: private static Func<List<KVP_E2S>, string> PlayerTie = lst_kvp => 2: map_prd2fn.Skip(1) 3: .Where(x => x.Key.Invoke(RenderDigits(dhPlayerOne).CompareTo(RenderDigits(dhPlayerTwo)))) 4: .Select(s => s.Value) 5: .First().Invoke(lst_kvp); After that, I realized I could now create a program completely without “if” statements or “for” loops! 1: static void Main(string[] args) 2: { 3: Dictionary<Predicate<int>, Action<Action<string>>> main = new Dictionary<Predicate<int>, Action<Action<string>>> 4: { 5: {(i => i.Equals(0)), PlayGame}, 6: {(i => true), Usage} 7: }; 8:   9: main[main.Keys.Where(m => m.Invoke(args.Length)).First()].Invoke(Display); 10: } …and there you have it. :) ZIPPED Project

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• Blog Buzz - Devoxx 2011

  - by Janice J. Heiss

  Some day I will make it to Devoxx – for now, I’m content to vicariously follow the blogs of attendees and pick up on what’s happening.  I’ve been doing more blog "fishing," looking for the best commentary on 2011 Devoxx. There’s plenty of food for thought – and the ideas are not half-baked.The bloggers are out in full, offering useful summaries and commentary on Devoxx goings-on.Constantin Partac, a Java developer and a member of Transylvania JUG, a community from Cluj-Napoca/Romania, offers an excellent summary of the Devoxx keynotes. Here’s a sample:“Oracle Opening Keynote and JDK 7, 8, and 9 Presentation•    Oracle is committed to Java and wants to provide support for it on any device.•    JSE 7 for Mac will be released next week.•    Oracle would like Java developers to be involved in JCP, to adopt a JSR and to attend local JUG meetings.•    JEE 7 will be released next year.•    JEE 7 is focused on cloud integration, some of the features are already implemented in glassfish 4 development branch.•    JSE 8 will be release in summer of 2013 due to “enterprise community request” as they can not keep the pace with an 18    month release cycle.•    The main features included in JSE8 are lambda support, project Jigsaw, new Date/Time API, project Coin++ and adding   support for sensors. JSE 9 probably will focus on some of these features:1.    self tuning JVM2.    improved native language integration3.    processing enhancement for big data4.    reification (adding runtime class type info for generic types)5.    unification of primitive and corresponding object classes6.    meta-object protocol in order to use type and methods define in other JVM languages7.    multi-tenancy8.    JVM resource management” Thanks Constantin! Ivan St. Ivanov, of SAP Labs Bulgaria, also commented on the keynotes with a different focus.  He summarizes Henrik Stahl’s look ahead to Java SE 8 and JavaFX 3.0; Cameron Purdy on Java EE and the cloud; celebrated Java Champion Josh Bloch on what’s good and bad about Java; Mark Reinhold’s quick look ahead to Java SE 9; and Brian Goetz on lambdas and default methods in Java SE 8. Here’s St. Ivanov’s account of Josh Bloch’s comments on the pluses of Java:“He started with the virtues of the platform. To name a few:    Tightly specified language primitives and evaluation order – int is always 32 bits and operations are executed always from left  to right, without compilers messing around    Dynamic linking – when you change a class, you need to recompile and rebuild just the jar that has it and not the whole application    Syntax  similarity with C/C++ – most existing developers at that time felt like at home    Object orientations – it was cool at that time as well as functional programming is today    It was statically typed language – helps in faster runtime, better IDE support, etc.    No operator overloading – well, I’m not sure why it is good. Scala has it for example and that’s why it is far better for defining DSLs. But I will not argue with Josh.”It’s worth checking out St. Ivanov’s summary of Bloch’s views on what’s not so great about Java as well. What's Coming in JAX-RS 2.0Marek Potociar, Principal Software Engineer at Oracle and currently specification lead of Java EE RESTful web services API (JAX-RS), blogged on his talk about what's coming in JAX-RS 2.0, scheduled for final release in mid-2012.  Here’s a taste:“Perhaps the most wanted addition to the JAX-RS is the Client API, that would complete the JAX-RS story, that is currently server-side only. In JAX-RS 2.0 we are adding a completely interface-based and fluent client API that blends nicely in with the existing fluent response builder pattern on the server-side. When we started with the client API, the first proposal contained around 30 classes. Thanks to the feedback from our Expert Group we managed to reduce the number of API classes to 14 (2 of them being exceptions)! The resulting is compact while at the same time we still managed to create an API that reflects the method invocation context flow (e.g. once you decide on the target URI and start setting headers on the request, your IDE will not try to offer you a URI setter in the code completion). This is a subtle but very important usability aspect of an API…” Obviously, Devoxx is a great Java conference, one that is hitting this year at a time when much is brewing in the platform and beginning to be anticipated.

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• Azure Mobile Services: available modules

  - by svdoever

  Azure Mobile Services has documented a set of objects available in your Azure Mobile Services server side scripts at their documentation page Mobile Services server script reference. Although the documented list is a nice list of objects for the common things you want to do, it will be sooner than later that you will look for more functionality to be included in your script, especially with the new provided feature that you can now create your custom API’s. If you use GIT it is now possible to add any NPM module (node package manager module, say the NuGet of the node world), but why include a module if it is already available out of the box. And you can only use GIT with Azure Mobile Services if you are an administrator on your Azure Mobile Service, not if you are a co-administrator (will be solved in the future). Until now I did some trial and error experimentation to test if a certain module was available. This is easiest to do as follows:   Create a custom API, for example named experiment. In this API use the following code: exports.get = function (request, response) { var module = "nonexistingmodule"; var m = require(module); response.send(200, "Module '%s' found.", module); }; You can now test your service with the following request in your browser: https://yourservice.azure-mobile.net/api/experiment If you get the result: {"code":500,"error":"Error: Internal Server Error"} you know that the module does not exist. In your logs you will find the following error: Error in script '/api/experiment.json'. Error: Cannot find module 'nonexistingmodule' [external code] atC:\DWASFiles\Sites\yourservice\VirtualDirectory0\site\wwwroot\App_Data\config\scripts\api\experiment.js:3:13[external code] If you require an existing (undocumented) module like the OAuth module in the following code, you will get success as a result: exports.get = function (request, response) { var module = "oauth"; var m = require(module); response.send(200, "Module '" + module + "' found."); }; If we look at the standard node.js documentation we see an extensive list of modules that can be used from your code. If we look at the list of files available in the Azure Mobile Services platform as documented in the blog post Azure Mobile Services: what files does it consist of? we see a folder node_modules with many more modules are used to build the Azure Mobile Services functionality on, but that can also be utilized from your server side node script code: apn - An interface to the Apple Push Notification service for Node.js. dpush - Send push notifications to Android devices using GCM. mpns - A Node.js interface to the Microsoft Push Notification Service (MPNS) for Windows Phone. wns - Send push notifications to Windows 8 devices using WNS. pusher - Node library for the Pusher server API (see also: http://pusher.com/) azure - Windows Azure Client Library for node. express - Sinatra inspired web development framework. oauth - Library for interacting with OAuth 1.0, 1.0A, 2 and Echo. Provides simplified client access and allows for construction of more complex apis and OAuth providers. request - Simplified HTTP request client. sax - An evented streaming XML parser in JavaScript sendgrid - A NodeJS implementation of the SendGrid Api. sqlserver – In node repository known as msnodesql - Microsoft Driver for Node.js for SQL Server. tripwire - Break out from scripts blocking node.js event loop. underscore - JavaScript's functional programming helper library. underscore.string - String manipulation extensions for Underscore.js javascript library. xml2js - Simple XML to JavaScript object converter. xmlbuilder - An XML builder for node.js. As stated before, many of these modules are used to provide the functionality of Azure Mobile Services platform, and in general should not be used directly. On the other hand, I needed OAuth badly to authenticate to the new v1.1 services of Twitter, and was very happy that a require('oauth') and a few lines of code did the job. Based on the above modules and a lot of code in the other javascript files in the Azure Mobile Services platform a set of global objects is provided that can be used from your server side node.js script code. In future blog posts I will go into more details with respect to how this code is built-up, all starting at the node.js express entry point app.js.

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• C# async and actors

  - by Alex.Davies

  If you read my last post about async, you might be wondering what drove me to write such odd code in the first place. The short answer is that .NET Demon is written using NAct Actors. Actors are an old idea, which I believe deserve a renaissance under C# 5. The idea is to isolate each stateful object so that only one thread has access to its state at any point in time. That much should be familiar, it's equivalent to traditional lock-based synchronization. The different part is that actors pass "messages" to each other rather than calling a method and waiting for it to return. By doing that, each thread can only ever be holding one lock. This completely eliminates deadlocks, my least favourite concurrency problem. Most people who use actors take this quite literally, and there are plenty of frameworks which help you to create message classes and loops which can receive the messages, inspect what type of message they are, and process them accordingly. But I write C# for a reason. Do I really have to choose between using actors and everything I love about object orientation in C#? Type safety Interfaces Inheritance Generics As it turns out, no. You don't need to choose between messages and method calls. A method call makes a perfectly good message, as long as you don't wait for it to return. This is where asynchonous methods come in. I have used NAct for a while to wrap my objects in a proxy layer. As long as I followed the rule that methods must always return void, NAct queued up the call for later, and immediately released my thread. When I needed to get information out of other actors, I could use EventHandlers and callbacks (continuation passing style, for any CS geeks reading), and NAct would call me back in my isolated thread without blocking the actor that raised the event. Using callbacks looks horrible though. To remind you: m_BuildControl.FilterEnabledForBuilding(    projects,    enabledProjects = m_OutOfDateProjectFinder.FilterNeedsBuilding(        enabledProjects,             newDirtyProjects =             {                 ....... Which is why I'm really happy that NAct now supports async methods. Now, methods are allowed to return Task rather than just void. I can await those methods, and C# 5 will turn the rest of my method into a continuation for me. NAct will run the other method in the other actor's context, but will make sure that when my method resumes, we're back in my context. Neither actor was ever blocked waiting for the other one. Apart from when they were actually busy doing something, they were responsive to concurrent messages from other sources. To be fair, you could use async methods with lock statements to achieve exactly the same thing, but it's ugly. Here's a realistic example of an object that has a queue of data that gets passed to another object to be processed: class QueueProcessor {    private readonly ItemProcessor m_ItemProcessor = ...     private readonly object m_Sync = new object();    private Queue<object> m_DataQueue = ...    private List<object> m_Results = ...     public async Task ProcessOne() {         object data = null;         lock (m_Sync)         {             data = m_DataQueue.Dequeue();         }         var processedData = await m_ItemProcessor.ProcessData(data); lock (m_Sync)         {             m_Results.Add(processedData);         }     } } We needed to write two lock blocks, one to get the data to process, one to store the result. The worrying part is how easily we could have forgotten one of the locks. Compare that to the version using NAct: class QueueProcessorActor : IActor { private readonly ItemProcessor m_ItemProcessor = ... private Queue<object> m_DataQueue = ... private List<object> m_Results = ... public async Task ProcessOne()     {         // We are an actor, it's always thread-safe to access our private fields         var data = m_DataQueue.Dequeue();         var processedData = await m_ItemProcessor.ProcessData(data);         m_Results.Add(processedData);     } } You don't have to explicitly lock anywhere, NAct ensures that your code will only ever run on one thread, because it's an actor. Either way, async is definitely better than traditional synchronous code. Here's a diagram of what a typical synchronous implementation might do: The left side shows what is running on the thread that has the lock required to access the QueueProcessor's data. The red section is where that lock is held, but doesn't need to be. Contrast that with the async version we wrote above: Here, the lock is released in the middle. The QueueProcessor is free to do something else. Most importantly, even if the ItemProcessor sometimes calls the QueueProcessor, they can never deadlock waiting for each other. So I thoroughly recommend you use async for all code that has to wait a while for things. And if you find yourself writing lots of lock statements, think about using actors as well. Using actors and async together really takes the misery out of concurrent programming.

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• Tracing Silex from PHP to the OS with DTrace

  - by cj

  In this blog post I show the full stack tracing of Brendan Gregg's php_syscolors.d script in the DTrace Toolkit. The Toolkit contains a dozen very useful PHP DTrace scripts and many more scripts for other languages and the OS. For this example, I'll trace the PHP micro framework Silex, which was the topic of the second of two talks by Dustin Whittle at a recent SF PHP Meetup. His slides are at Silex: From Micro to Full Stack. Installing DTrace and PHP The php_syscolors.d script uses some static PHP probes and some kernel probes. For Oracle Linux I discussed installing DTrace and PHP in DTrace PHP Using Oracle Linux 'playground' Pre-Built Packages. On other platforms with DTrace support, follow your standard procedures to enable DTrace and load the correct providers. The sdt and systrace providers are required in addition to fasttrap. On Oracle Linux, I loaded the DTrace modules like: # modprobe fasttrap # modprobe sdt # modprobe systrace # chmod 666 /dev/dtrace/helper Installing the DTrace Toolkit I download DTraceToolkit-0.99.tar.gz and extracted it: $ tar -zxf DTraceToolkit-0.99.tar.gz The PHP scripts are in the Php directory and examples in the Examples directory. Installing Silex I downloaded the "fat" Silex .tgz file from the download page and extracted it: $ tar -zxf silex_fat.tgz I changed the demonstration silex/web/index.php so I could use the PHP development web server: <?php // web/index.php $filename = __DIR__.preg_replace('#(\?.*)$#', '', $_SERVER['REQUEST_URI']); if (php_sapi_name() === 'cli-server' && is_file($filename)) { return false; } require_once __DIR__.'/../vendor/autoload.php'; $app = new Silex\Application(); //$app['debug'] = true; $app->get('/hello', function() { return 'Hello!'; }); $app->run(); ?> Running DTrace The php_syscolors.d script uses the -Z option to dtrace, so it can be started before PHP, i.e. when there are zero of the requested probes available to be traced. I ran DTrace like: # cd DTraceToolkit-0.99/Php # ./php_syscolors.d Next, I started the PHP developer web server in a second terminal: $ cd silex $ php -S localhost:8080 -t web web/index.php At this point, the web server is idle, waiting for requests. DTrace is idle, waiting for the probes in php_syscolors.d to be fired, at which time the action associated with each probe will run. I then loaded the demonstration page in a browser: http://localhost:8080/hello When the request was fulfilled and the simple output of "Hello" was displayed, I ^C'd php and dtrace in their terminals to stop them. DTrace output over a thousand lines long had been generated. Here is one snippet from when run() was invoked: C PID/TID DELTA(us) FILE:LINE TYPE -- NAME ... 1 4765/4765 21 Application.php:487 func -> run 1 4765/4765 29 ClassLoader.php:182 func -> loadClass 1 4765/4765 17 ClassLoader.php:198 func -> findFile 1 4765/4765 31 ":- syscall -> access 1 4765/4765 26 ":- syscall <- access 1 4765/4765 16 ClassLoader.php:198 func <- findFile 1 4765/4765 25 ":- syscall -> newlstat 1 4765/4765 15 ":- syscall <- newlstat 1 4765/4765 13 ":- syscall -> newlstat 1 4765/4765 13 ":- syscall <- newlstat 1 4765/4765 22 ":- syscall -> newlstat 1 4765/4765 14 ":- syscall <- newlstat 1 4765/4765 15 ":- syscall -> newlstat 1 4765/4765 60 ":- syscall <- newlstat 1 4765/4765 13 ":- syscall -> newlstat 1 4765/4765 13 ":- syscall <- newlstat 1 4765/4765 20 ":- syscall -> open 1 4765/4765 16 ":- syscall <- open 1 4765/4765 26 ":- syscall -> newfstat 1 4765/4765 12 ":- syscall <- newfstat 1 4765/4765 17 ":- syscall -> newfstat 1 4765/4765 12 ":- syscall <- newfstat 1 4765/4765 12 ":- syscall -> newfstat 1 4765/4765 12 ":- syscall <- newfstat 1 4765/4765 20 ":- syscall -> mmap 1 4765/4765 14 ":- syscall <- mmap 1 4765/4765 3201 ":- syscall -> mmap 1 4765/4765 27 ":- syscall <- mmap 1 4765/4765 1233 ":- syscall -> munmap 1 4765/4765 53 ":- syscall <- munmap 1 4765/4765 15 ":- syscall -> close 1 4765/4765 13 ":- syscall <- close 1 4765/4765 34 Request.php:32 func -> main 1 4765/4765 22 Request.php:32 func <- main 1 4765/4765 31 ClassLoader.php:182 func <- loadClass 1 4765/4765 33 Request.php:249 func -> createFromGlobals 1 4765/4765 29 Request.php:198 func -> __construct 1 4765/4765 24 Request.php:218 func -> initialize 1 4765/4765 26 ClassLoader.php:182 func -> loadClass 1 4765/4765 89 ClassLoader.php:198 func -> findFile 1 4765/4765 43 ":- syscall -> access ... The output shows PHP functions being called and returning (and where they are located) and which system calls the PHP functions in turn invoked. The time each line took from the previous one is displayed in the third column. The first column is the CPU number. In this example, the process was always on CPU 1 so the output is naturally ordered without requiring post-processing, or the D script requiring to be modified to display a time stamp. On a terminal, the output of php_syscolors.d is color-coded according to whether each function is a PHP or system one, hence the file name. Summary With one tool, I was able to trace the interaction of a user application with the operating system. I was able to do this to an application running "live" in a web context. The DTrace Toolkit provides a very handy repository of DTrace information. Even though the PHP scripts were created in the time frame of the original PHP DTrace PECL extension, which only had PHP function entry and return probes, the scripts provide core examples for custom investigation and resolution scripts. You can easily adapt the ideas and and create scripts using the other PHP static probes, which are listed in the PHP Manual. Because DTrace is "always on", you can take advantage of it to resolve development questions or fix production situations.

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• Interview with Geoff Bones, developer on SQL Storage Compress

  - by red(at)work

  How did you come to be working at Red Gate? I've been working at Red Gate for nine months; before that I had been at a multinational engineering company. A number of my colleagues had left to work at Red Gate and spoke very highly of it, but I was happy in my role and thought, 'It can't be that great there, surely? They'll be back!' Then one day I visited to catch up them over lunch in the Red Gate canteen. I was so impressed with what I found there, that, three days later, I'd applied for a role as a developer. And how did you get into software development? My first job out of university was working as a systems programmer on IBM mainframes. This was quite a while ago: there was a lot of assembler and loading programs from tape drives and that kind of stuff. I learned a lot about how computers work, and this stood me in good stead when I moved over the development in the 90s. What's the best thing about working as a developer at Red Gate? Where should I start? One of the great things as a developer at Red Gate is the useful feedback and close contact we have with the people who use our products, either directly at trade shows and other events or through information coming through the product managers. The company's whole ethos is built around assisting the user, and this is in big contrast to my previous development roles. We aim to produce tools that people really want to use, that they enjoy using, and, as a developer, this is a great thing to aim for and a great feeling when we get it right. At Red Gate we also try to cut out the things that distract and stop us doing our jobs. As a developer, this means that I can focus on the code and the product I'm working on, knowing that others are doing a first-class job of making sure that the builds are running smoothly and that I'm getting great feedback from the testers. We keep our process light and effective, as we want to produce great software more than we want to produce great audit trails. Tell us a bit about the products you are currently working on. You mean HyperBac? First let me explain a bit about what HyperBac is. At heart it's a compression and encryption technology, but with a few added features that open up a wealth of really exciting possibilities. Right now we have the HyperBac technology in just three products: SQL HyperBac, SQL Virtual Restore and SQL Storage Compress, but we're only starting to develop what it can do. My personal favourite is SQL Virtual Restore; for example, I love the way you can use it to run independent test databases that are all backed by a single compressed backup. I don't think the market yet realises the kind of things you do once you are using these products. On the other hand, the benefits of SQL Storage Compress are straightforward: run your databases but use only 20% of the disk space. Databases are getting larger and larger, and, as they do, so does your ROI. What's a typical day for you? My days are pretty varied. We have our daily team stand-up meeting and then sometimes I will work alone on a current issue, or I'll be pair programming with one of my colleagues. From time to time we give half a day up to future planning with the team, when we look at the long and short term aims for the product and working out the development priorities. I also get to go to conferences and events, which is unusual for a development role and gives me the chance to meet and talk to our customers directly. Have you noticed anything different about developing tools for DBAs rather than other IT kinds of user? It seems to me that DBAs are quite independent minded; they know exactly what the problem they are facing is, and often have a solution in mind before they begin to look for what's on the market. This means that they're likely to cherry-pick tools from a range of vendors, picking the ones that are the best fit for them and that disrupt their environments the least. When I've met with DBAs, I've often been very impressed at their ability to summarise their set up, the issues, the obstacles they face when implementing a tool and their plans for their environment. It's easier to develop products for this audience as they give such a detailed overview of their needs, and I feel I understand their problems.

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• Productivity vs Security [closed]

  - by nerijus

  Really do not know is this right place to ask such a questions. But it is about programming in a different light. So, currently contracting with company witch pretends to be big corporation. Everyone is so important that all small issues like developers are ignored. Give you a sample: company VPN is configured so that if you have VPN then HTTP traffic is banned. Bearing this in mind can you imagine my workflow: Morning. Ok time to get latest source. Ups, no VPN. Let’s connect. Click-click. 3 sec. wait time. Ok getting source. Do I have emails? Ups. VPN is on, can’t check my emails. Need to wait for source to come up. Finally here it is! Ok Click-click VPN is gone. What is in my email. Someone reported a bug. Good, let’s track it down. It is in TFS already. Oh, dam, I need VPN. Click-click. Ok, there is description. Yea, I have seen this issue in stachoverflow.com. Let’s go there. Ups, no internet. Click-click. No internet. What? IPconfig… DHCP server kicked me out. Dam. Renew ip. 1..2..3. Ok internet is back. Google: site: stachoverflow.com 3 min. I have solution. Great I love stackoverflow.com. Don’t want to remember days where there was no stackoveflow.com. Ok. Copy paste this like to studio. Dam, studio is stalled, can’t reach files on TFS. Click-click. VPN is back. Get source out, paste my code. Grand. Let’s see what other comments about an issue in stackoverflow.com tells. Hmm.. There is a link. Click. Dammit! No internet. Click-click. No internet. DHCP kicked me out. Dammit. Now it is even worse: this happens 3-4 times a day. After certain amount of VPN connections open\closed my internet goes down solid. Only way to get internet back is reboot. All my browser tabs/SQL windows/studio will be gone. This happened just now when I am typing this. Back to issue I am solving right now: I am getting frustrated - I do not care about better solution for this issue. Let’s do it somehow and forget. This Click-click barrier between internet and TFS kills me… Sounds familiar? You could say there are VPN settings to change. No! This is company laptop, not allowed to do changes. I am very very lucky to have admin privileges on my machine. Most of developers don’t. So just learned to live with this frustration. It takes away 40-60 minutes daily. Tried to email company support, admins. They are too important ant too busy with something that just ignored my little man’s problem. Politely ignored. Question is: Is this normal in corporate world? (Have been in States, Canada, Germany. Never seen this.)

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• Adopt-a-JSR for Java EE 7 - Getting Started

  - by arungupta

  Adopt-a-JSR is an initiative started by JUG leaders to encourage JUG members to get involved in a JSR, in order to increase grass roots participation. This allows JUG members to provide early feedback to specifications before they are finalized in the JCP. The standards in turn become more complete and developer-friendly after getting feedback from a wide variety of audience. adoptajsr.org provide more details about the logistics and benefits for you and your JUG. A similar activity was conducted for OpenJDK as well. Markus Eisele also provide a great introduction to the program (in German). Java EE 7 (JSR 342) is scheduled to go final in Q2 2013. There are several new JSRs that are getting included in the platform (e.g. WebSocket, JSON, and Batch), a few existing ones are getting an overhaul (e.g. JAX-RS 2 and JMS 2), and several other getting minor updates (e.g. JPA 2.1 and Servlets 3.1). Each Java EE 7 JSR can leverage your expertise and would love your JUG to adopt a JSR. What does it mean to adopt a JSR ? Your JUG is going to identify a particular JSR, or multiple JSRs, that is of interest to the JUG members. This is mostly done by polling/discussing on your local JUG members list. Your JUG will download and review the specification(s) and javadocs for clarity and completeness. The complete set of Java EE 7 specifications, their download links, and EG archives are listed here. glassfish.org/adoptajsr provide specific areas where different specification leads are looking for feedback. Your JUG can then think of a sample application that can be built using the chosen specification(s). An existing use case (from work or a personal hobby project) may be chosen to be implemented instead. This is where your creativity and uniqueness comes into play. Most of the implementations are already integrated in GlassFish 4 and others will be integrated soon. You can also explore integration of multiple technologies and provide feedback on the simplicity and ease-of-use of the programming model. Especially look for integration with existing Java EE technologies and see if you find any discrepancies. Report any missing features that may be included in future release of the specification. The most important part is to provide feedback by filing bugs on the corresponding spec or RI project. Any thing that is not clear either in the spec or implementation should be filed as a bug. This is what will ensure that specification and implementation leads are getting the required feedback and improving the quality of the final deliverable of the JSR. How do I get started ? A simple way to get started can be achieved by following S.M.A.R.T. as explained below. Specific Identify who all will be involved ? What would you like to accomplish ? For example, even though building a sample app will provide real-world validity of the API but because of time constraints you may identify that reviewing the specification and javadocs only can be accomplished. Establish a time frame by which the activities need to be complete. Measurable Define a success for metrics. For example, this could be the number of bugs filed. Remember, quality of bugs is more important that quantity of bugs. Define your end goal, for example, reviewing 4 chapters of the specification or completing the sample application. Create a dashboard that will highlight your JUG's contribution to this effort. Attainable Make sure JUG members understand the time commitment required for providing feedback. This can vary based upon the level of involvement (any is good!) and the number of specifications picked. adoptajsr.org defines different categories of involvement. Once again, any level of involvement is good. Just reviewing a chapter, a section, or javadocs for your usecase is helpful. Relevant Pick JSRs that JUG members are willing and able to work. If the JUG members are not interested then they might loose motivation half-way through. The "able" part is tricky as you can always stretch yourself and learn a new skill ;-) Time-bound Define a time table of activities with clearly defined tasks. A tentative time table may look like: Dec 25: Discuss and agree upon the specifications with JUG Jan 1: Start Adopt-a-JSR for Java EE 7 Jan 15: Initial spec reading complete. Keep thinking through the application that will be implemented. Jan 22: Early design of the sample application is ready Jan 29: JUG members agree upon the application Next 4 weeks: Implement the application Of course, you'll need to alter this based upon your commitment. Maintaining an activity dashboard will help you monitor and track the progress. Make sure to keep filing bugs through out the process! 12 JUGs from around the world (SouJava, Campinas JUG, Chennai JUG, London Java Community, BeJUG, Morocco JUG, Peru JUG, Indonesia JUG, Congo JUG, Silicon Valley JUG, Madrid JUG, and Houston JUG) have already adopted one of the Java EE 7 JSRs. I'm already helping some JUGs bootstrap and would love to help your JUG too. What are you waiting for ?

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• Community Outreach - Where Should I Go

  - by Roger Brinkley

  A few days ago I was talking to person new to community development and they asked me what guidelines I used to determine the worthiness of a particular event. After our conversation was over I thought about it a little bit more and figured out there are three ways to determine if any event (be it conference, blog, podcast or other social medias) is worth doing: Transferability, Multiplication, and Impact. Transferability - Is what I have to say useful to the people that are going to hear it. For instance, consider a company that has product offering that can connect up using a number of languages like Scala, Grovey or Java. Sending a Scala expert to talk about Scala and the product is not transferable to a Java User Group, but a Java expert doing the same talk with a Java slant is. Similarly, talking about JavaFX to any Java User Group meeting in Brazil was pretty much a wasted effort until it was open sourced. Once it was open sourced it was well received. You can also look at transferability in relation to the subject matter that you're dealing with. How transferable is a presentation that I create. Can I, or a technical writer on the staff, turn it into some technical document. Could it be converted into some type of screen cast. If we have a regular podcast can we make a reference to the document, catch the high points or turn it into a interview. Is there a way of using this in the sales group. In other words is the document purely one dimensional or can it be re-purposed in other forms. Multiplication - On every trip I'm looking for 2 to 5 solid connections that I can make with developers. These are long term connections, because I know that once that relationship is established it will lead to another 2 - 5 from that connection and within a couple of years were talking about some 100 connections from just one developer. For instance, when I was working on JavaHelp in 2000 I hired a science teacher with a programming background. We've developed a very tight relationship over the year though we rarely see each other more than once a year. But at this JavaOne, one of his employees came up to me and said, "Richard (Rick Hard in Czech) told me to tell you that he couldn't make it to JavaOne this year but if I saw you to tell you hi". Another example is from my Mobile & Embedded days in Brasil. On our very first FISL trip about 5 years ago there were two university students that had created a project called "Marge". Marge was a Bluetooth framework that made connecting bluetooth devices easier. I invited them to a "Sun" dinner that evening. Originally they were planning on leaving that afternoon, but they changed their plans recognizing the opportunity. Their eyes were as big a saucers when they realized the level of engineers at the meeting. They went home started a JUG in Florianoplis that we've visited more than a couple of times. One of them went to work for Brazilian government lab like Berkley Labs, MIT Lab, John Hopkins Applied Physicas Labs or Lincoln Labs in the US. That presented us with an opportunity to show Embedded Java as a possibility for some of the work they were doing there. Impact - The final criteria is how life changing is what I'm going to say be to the individuals I'm reaching. A t-shirt is just a token, but when I reach down and tug at their developer hearts then I know I've succeeded. I'll never forget one time we flew all night to reach Joan Pasoa in Northern Brazil. We arrived at 2am went immediately to our hotel only to be woken up at 6 am to travel 2 hours by car to the presentation hall. When we arrived we were totally exhausted. Outside the facility there were 500 people lined up to hear 6 speakers for the day. That itself was uplifting.  I delivered one of my favorite talks on "I have passion". It was a talk on golf and embedded java development, "Find your passion". When we finished a couple of first year students came up to me and said how much my talk had inspired them. FISL is another great example. I had been about 4 years in a row. FISL is a very young group of developers so capturing their attention is important. Several of the students will come back 2 or 3 years later and ask me questions about research or jobs. And then there's Louis. Louis is one my favorite Brazilians. I can only describe him as a big Brazilian teddy bear. I see him every year at FISL. He works primarily in Java EE but he's attended every single one of my talks over the last 4 years. I can't tell you why, but he always greets me and gives me a hug. For some reason I've had a real impact. And of course when it comes to impact you don't just measure a presentation but every single interaction you have at an event. It's the hall way conversations, the booth conversations, but more importantly it's the conversations at dinner tables or in the cars when you're getting transported to an event. There's a good story that illustrates this. Last year in the spring I was traveling to Goiânia in Brazil. I've been there many times and leaders there no me well. One young man has picked me up at the airport on more than one occasion. We were going out to dinner one evening and he brought his girl friend along. One thing let to another and I eventually asked him, in front of her, "Why haven't you asked her to marry you?" There were all kinds of excuses and she just looked at him and smiled. When I came back in December for JavaOne he came and sought me. "I just want to tell you that I thought a lot about what you said, and I asked her to marry me. We're getting married next Spring." Sometimes just one presentation is all it takes to make an impact. Other times it takes years. Some impacts are directly related to the company and some are more personal in nature. It doesn't matter which it is because it's having the impact that matters.

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• C#/.NET Little Wonders: Static Char Methods

  - by James Michael Hare

  Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Often times in our code we deal with the bigger classes and types in the BCL, and occasionally forgot that there are some nice methods on the primitive types as well.  Today we will discuss some of the handy static methods that exist on the char (the C# alias of System.Char) type. The Background I was examining a piece of code this week where I saw the following: 1: // need to get the 5th (offset 4) character in upper case 2: var type = symbol.Substring(4, 1).ToUpper(); 3:  4: // test to see if the type is P 5: if (type == "P") 6: { 7: // ... do something with P type... 8: } Is there really any error in this code?  No, but it still struck me wrong because it is allocating two very short-lived throw-away strings, just to store and manipulate a single char: The call to Substring() generates a new string of length 1 The call to ToUpper() generates a new upper-case version of the string from Step 1. In my mind this is similar to using ToUpper() to do a case-insensitive compare: it isn’t wrong, it’s just much heavier than it needs to be (for more info on case-insensitive compares, see #2 in 5 More Little Wonders). One of my favorite books is the C++ Coding Standards: 101 Rules, Guidelines, and Best Practices by Sutter and Alexandrescu.  True, it’s about C++ standards, but there’s also some great general programming advice in there, including two rules I love:         8. Don’t Optimize Prematurely         9. Don’t Pessimize Prematurely We all know what #8 means: don’t optimize when there is no immediate need, especially at the expense of readability and maintainability.  I firmly believe this and in the axiom: it’s easier to make correct code fast than to make fast code correct.  Optimizing code to the point that it becomes difficult to maintain often gains little and often gives you little bang for the buck. But what about #9?  Well, for that they state: “All other things being equal, notably code complexity and readability, certain efficient design patterns and coding idioms should just flow naturally from your fingertips and are no harder to write then the pessimized alternatives. This is not premature optimization; it is avoiding gratuitous pessimization.” Or, if I may paraphrase: “where it doesn’t increase the code complexity and readability, prefer the more efficient option”. The example code above was one of those times I feel where we are violating a tacit C# coding idiom: avoid creating unnecessary temporary strings.  The code creates temporary strings to hold one char, which is just unnecessary.  I think the original coder thought he had to do this because ToUpper() is an instance method on string but not on char.  What he didn’t know, however, is that ToUpper() does exist on char, it’s just a static method instead (though you could write an extension method to make it look instance-ish). This leads me (in a long-winded way) to my Little Wonders for the day… Static Methods of System.Char So let’s look at some of these handy, and often overlooked, static methods on the char type: IsDigit(), IsLetter(), IsLetterOrDigit(), IsPunctuation(), IsWhiteSpace() Methods to tell you whether a char (or position in a string) belongs to a category of characters. IsLower(), IsUpper() Methods that check if a char (or position in a string) is lower or upper case ToLower(), ToUpper() Methods that convert a single char to the lower or upper equivalent. For example, if you wanted to see if a string contained any lower case characters, you could do the following: 1: if (symbol.Any(c => char.IsLower(c))) 2: { 3: // ... 4: } Which, incidentally, we could use a method group to shorten the expression to: 1: if (symbol.Any(char.IsLower)) 2: { 3: // ... 4: } Or, if you wanted to verify that all of the characters in a string are digits: 1: if (symbol.All(char.IsDigit)) 2: { 3: // ... 4: } Also, for the IsXxx() methods, there are overloads that take either a char, or a string and an index, this means that these two calls are logically identical: 1: // check given a character 2: if (char.IsUpper(symbol[0])) { ... } 3:  4: // check given a string and index 5: if (char.IsUpper(symbol, 0)) { ... } Obviously, if you just have a char, then you’d just use the first form.  But if you have a string you can use either form equally well. As a side note, care should be taken when examining all the available static methods on the System.Char type, as some seem to be redundant but actually have very different purposes.  For example, there are IsDigit() and IsNumeric() methods, which sound the same on the surface, but give you different results. IsDigit() returns true if it is a base-10 digit character (‘0’, ‘1’, … ‘9’) where IsNumeric() returns true if it’s any numeric character including the characters for ½, ¼, etc. Summary To come full circle back to our opening example, I would have preferred the code be written like this: 1: // grab 5th char and take upper case version of it 2: var type = char.ToUpper(symbol[4]); 3:  4: if (type == 'P') 5: { 6: // ... do something with P type... 7: } Not only is it just as readable (if not more so), but it performs over 3x faster on my machine:    1,000,000 iterations of char method took: 30 ms, 0.000050 ms/item.    1,000,000 iterations of string method took: 101 ms, 0.000101 ms/item. It’s not only immediately faster because we don’t allocate temporary strings, but as an added bonus there less garbage to collect later as well.  To me this qualifies as a case where we are using a common C# performance idiom (don’t create unnecessary temporary strings) to make our code better. Technorati Tags: C#,CSharp,.NET,Little Wonders,char,string

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• The Sensemaking Spectrum for Business Analytics: Translating from Data to Business Through Analysis

  - by Joe Lamantia

  One of the most compelling outcomes of our strategic research efforts over the past several years is a growing vocabulary that articulates our cumulative understanding of the deep structure of the domains of discovery and business analytics. Modes are one example of the deep structure we’ve found.  After looking at discovery activities across a very wide range of industries, question types, business needs, and problem solving approaches, we've identified distinct and recurring kinds of sensemaking activity, independent of context.  We label these activities Modes: Explore, compare, and comprehend are three of the nine recognizable modes.  Modes describe *how* people go about realizing insights.  (Read more about the programmatic research and formal academic grounding and discussion of the modes here: https://www.researchgate.net/publication/235971352_A_Taxonomy_of_Enterprise_Search_and_Discovery) By analogy to languages, modes are the 'verbs' of discovery activity.  When applied to the practical questions of product strategy and development, the modes of discovery allow one to identify what kinds of analytical activity a product, platform, or solution needs to support across a spread of usage scenarios, and then make concrete and well-informed decisions about every aspect of the solution, from high-level capabilities, to which specific types of information visualizations better enable these scenarios for the types of data users will analyze. The modes are a powerful generative tool for product making, but if you've spent time with young children, or had a really bad hangover (or both at the same time...), you understand the difficult of communicating using only verbs.  So I'm happy to share that we've found traction on another facet of the deep structure of discovery and business analytics.  Continuing the language analogy, we've identified some of the ‘nouns’ in the language of discovery: specifically, the consistently recurring aspects of a business that people are looking for insight into.  We call these discovery Subjects, since they identify *what* people focus on during discovery efforts, rather than *how* they go about discovery as with the Modes. Defining the collection of Subjects people repeatedly focus on allows us to understand and articulate sense making needs and activity in more specific, consistent, and complete fashion.  In combination with the Modes, we can use Subjects to concretely identify and define scenarios that describe people’s analytical needs and goals.  For example, a scenario such as ‘Explore [a Mode] the attrition rates [a Measure, one type of Subject] of our largest customers [Entities, another type of Subject] clearly captures the nature of the activity — exploration of trends vs. deep analysis of underlying factors — and the central focus — attrition rates for customers above a certain set of size criteria — from which follow many of the specifics needed to address this scenario in terms of data, analytical tools, and methods. We can also use Subjects to translate effectively between the different perspectives that shape discovery efforts, reducing ambiguity and increasing impact on both sides the perspective divide.  For example, from the language of business, which often motivates analytical work by asking questions in business terms, to the perspective of analysis.  The question posed to a Data Scientist or analyst may be something like “Why are sales of our new kinds of potato chips to our largest customers fluctuating unexpectedly this year?” or “Where can innovate, by expanding our product portfolio to meet unmet needs?”.  Analysts translate questions and beliefs like these into one or more empirical discovery efforts that more formally and granularly indicate the plan, methods, tools, and desired outcomes of analysis.  From the perspective of analysis this second question might become, “Which customer needs of type ‘A', identified and measured in terms of ‘B’, that are not directly or indirectly addressed by any of our current products, offer 'X' potential for ‘Y' positive return on the investment ‘Z' required to launch a new offering, in time frame ‘W’?  And how do these compare to each other?”.  Translation also happens from the perspective of analysis to the perspective of data; in terms of availability, quality, completeness, format, volume, etc. By implication, we are proposing that most working organizations — small and large, for profit and non-profit, domestic and international, and in the majority of industries — can be described for analytical purposes using this collection of Subjects.  This is a bold claim, but simplified articulation of complexity is one of the primary goals of sensemaking frameworks such as this one.  (And, yes, this is in fact a framework for making sense of sensemaking as a category of activity - but we’re not considering the recursive aspects of this exercise at the moment.) Compellingly, we can place the collection of subjects on a single continuum — we call it the Sensemaking Spectrum — that simply and coherently illustrates some of the most important relationships between the different types of Subjects, and also illuminates several of the fundamental dynamics shaping business analytics as a domain.  As a corollary, the Sensemaking Spectrum also suggests innovation opportunities for products and services related to business analytics. The first illustration below shows Subjects arrayed along the Sensemaking Spectrum; the second illustration presents examples of each kind of Subject.  Subjects appear in colors ranging from blue to reddish-orange, reflecting their place along the Spectrum, which indicates whether a Subject addresses more the viewpoint of systems and data (Data centric and blue), or people (User centric and orange).  This axis is shown explicitly above the Spectrum.  Annotations suggest how Subjects align with the three significant perspectives of Data, Analysis, and Business that shape business analytics activity.  This rendering makes explicit the translation and bridging function of Analysts as a role, and analysis as an activity. Subjects are best understood as fuzzy categories [http://georgelakoff.files.wordpress.com/2011/01/hedges-a-study-in-meaning-criteria-and-the-logic-of-fuzzy-concepts-journal-of-philosophical-logic-2-lakoff-19731.pdf], rather than tightly defined buckets.  For each Subject, we suggest some of the most common examples: Entities may be physical things such as named products, or locations (a building, or a city); they could be Concepts, such as satisfaction; or they could be Relationships between entities, such as the variety of possible connections that define linkage in social networks.  Likewise, Events may indicate a time and place in the dictionary sense; or they may be Transactions involving named entities; or take the form of Signals, such as ‘some Measure had some value at some time’ - what many enterprises understand as alerts.   The central story of the Spectrum is that though consumers of analytical insights (represented here by the Business perspective) need to work in terms of Subjects that are directly meaningful to their perspective — such as Themes, Plans, and Goals — the working realities of data (condition, structure, availability, completeness, cost) and the changing nature of most discovery efforts make direct engagement with source data in this fashion impossible.  Accordingly, business analytics as a domain is structured around the fundamental assumption that sense making depends on analytical transformation of data.  Analytical activity incrementally synthesizes more complex and larger scope Subjects from data in its starting condition, accumulating insight (and value) by moving through a progression of stages in which increasingly meaningful Subjects are iteratively synthesized from the data, and recombined with other Subjects.  The end goal of  ‘laddering’ successive transformations is to enable sense making from the business perspective, rather than the analytical perspective.Synthesis through laddering is typically accomplished by specialized Analysts using dedicated tools and methods. Beginning with some motivating question such as seeking opportunities to increase the efficiency (a Theme) of fulfillment processes to reach some level of profitability by the end of the year (Plan), Analysts will iteratively wrangle and transform source data Records, Values and Attributes into recognizable Entities, such as Products, that can be combined with Measures or other data into the Events (shipment of orders) that indicate the workings of the business.  More complex Subjects (to the right of the Spectrum) are composed of or make reference to less complex Subjects: a business Process such as Fulfillment will include Activities such as confirming, packing, and then shipping orders.  These Activities occur within or are conducted by organizational units such as teams of staff or partner firms (Networks), composed of Entities which are structured via Relationships, such as supplier and buyer.  The fulfillment process will involve other types of Entities, such as the products or services the business provides.  The success of the fulfillment process overall may be judged according to a sophisticated operating efficiency Model, which includes tiered Measures of business activity and health for the transactions and activities included.  All of this may be interpreted through an understanding of the operational domain of the businesses supply chain (a Domain).   We'll discuss the Spectrum in more depth in succeeding posts.

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• MySQL Connector/Net 6.6.3 Beta 2 has been released

  - by fernando

  MySQL Connector/Net 6.6.3, a new version of the all-managed .NET driver for MySQL has been released.  This is the second of two beta releases intended to introduce users to the new features in the release. This release is feature complete it should be stable enough for users to understand the new features and how we expect them to work.  As is the case with all non-GA releases, it should not be used in any production environment.  It is appropriate for use with MySQL server versions 5.0-5.6. It is now available in source and binary form from http://dev.mysql.com/downloads/connector/net/#downloads and mirror sites (note that not all mirror sites may be up to date at this point-if you can't find this version on some mirror, please try again later or choose another download site.) The 6.6 version of MySQL Connector/Net brings the following new features:   * Stored routine debugging   * Entity Framework 4.3 Code First support   * Pluggable authentication (now third parties can plug new authentications mechanisms into the driver).   * Full Visual Studio 2012 support: everything from Server Explorer to Intellisense&   the Stored Routine debugger. Stored Procedure Debugging ------------------------------------------- We are very excited to introduce stored procedure debugging into our Visual Studio integration.  It works in a very intuitive manner by simply clicking 'Debug Routine' from Server Explorer. You can debug stored routines, functions&   triggers. These release contains fixes specific of the debugger as well as other fixes specific of other areas of Connector/NET:   * Added feature to define initial values for InOut stored procedure arguments.   * Debugger: Fixed Visual Studio locked connection after debugging a routine.   * Fix for bug Cannot Create an Entity with a Key of Type String (MySQL bug #65289, Oracle bug #14540202).   * Fix for bug "CacheServerProperties can cause 'Packet too large' error". MySQL Bug #66578 Orabug #14593547.   * Fix for handling unnamed parameter in MySQLCommand. This fix allows the mysqlcommand to handle parameters without requiring naming (e.g. INSERT INTO Test (id,name) VALUES (?, ?) ) (MySQL Bug #66060, Oracle bug #14499549).   * Fixed end of line issue when debugging a routine.   * Added validation to avoid overwriting a routine backup file when it hasn't changed.   * Fixed inheritance on Entity Framework Code First scenarios. (MySql bug #63920 and Oracle bug #13582335).   * Fixed "Trying to customize column precision in Code First does not work" (MySql bug #65001, Oracle bug #14469048).   * Fixed bug ASP.NET Membership database fails on MySql database UTF32 (MySQL bug #65144, Oracle bug #14495292).   * Fix for MySqlCommand.LastInsertedId holding only 32 bit values (MySql bug #65452, Oracle bug #14171960).   * Fixed "Decimal type should have digits at right of decimal point", now default is 2, and user's changes in     EDM designer are recognized (MySql bug #65127, Oracle bug #14474342).   * Fix for NullReferenceException when saving an uninitialized row in Entity Framework (MySql bug #66066, Oracle bug #14479715).   * Fix for error when calling RoleProvider.RemoveUserFromRole(): causes an exception due to a wrong table being used (MySql bug #65805, Oracle bug #14405338).   * Fix for "Memory Leak on MySql.Data.MySqlClient.MySqlCommand", too many MemoryStream's instances created (MySql bug #65696, Oracle bug #14468204).   * Added ANTLR attribution notice (Oracle bug #14379162).   * Fix for debugger failing when having a routine with an if-elseif-else.   * Also the programming interface for authentication plugins has been redefined. Some limitations remains, due to the current debugger architecture:   * Some MySQL functions cannot be debugged currently (get_lock, release_lock, begin, commit, rollback, set transaction level)..   * Only one debug session may be active on a given server. The Debugger is feature complete at this point. We look forward to your feedback. Documentation ------------------------------------- You can view current Connector/Net documentation at http://dev.mysql.com/doc/refman/5.5/en/connector-net.html You can find our team blog at http://blogs.oracle.com/MySQLOnWindows. You can also post questions on our forums at http://forums.mysql.com/. Enjoy and thanks for the support!

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• Functional Adaptation

  - by Charles Courchaine

  In real life and OO programming we’re often faced with using adapters, DVI to VGA, 1/4” to 1/8” audio connections, 110V to 220V, wrapping an incompatible interface with a new one, and so on.  Where the adapter pattern is generally considered for interfaces and classes a similar technique can be applied to method signatures.  To be fair, this adaptation is generally used to reduce the number of parameters but I’m sure there are other clever possibilities to be had.  As Jan questioned in the last post, how can we use a common method to execute an action if the action has a differing number of parameters, going back to the greeting example it was suggested having an AddName method that takes a first and last name as parameters.  This is exactly what we’ll address in this post. Let’s set the stage with some review and some code changes.  First, our method that handles the setup/tear-down infrastructure for our WCF service: 1: private static TResult ExecuteGreetingFunc<TResult>(Func<IGreeting, TResult> theGreetingFunc) 2: { 3: IGreeting aGreetingService = null; 4: try 5: { 6: aGreetingService = GetGreetingChannel(); 7: return theGreetingFunc(aGreetingService); 8: } 9: finally 10: { 11: CloseWCFChannel((IChannel)aGreetingService); 12: } 13: } Our original AddName method: 1: private static string AddName(string theName) 2: { 3: return ExecuteGreetingFunc<string>(theGreetingService => theGreetingService.AddName(theName)); 4: } Our new AddName method: 1: private static int AddName(string firstName, string lastName) 2: { 3: return ExecuteGreetingFunc<int>(theGreetingService => theGreetingService.AddName(firstName, lastName)); 4: } Let’s change the AddName method, just a little bit more for this example and have it take the greeting service as a parameter. 1: private static int AddName(IGreeting greetingService, string firstName, string lastName) 2: { 3: return greetingService.AddName(firstName, lastName); 4: } The new signature of AddName using the Func delegate is now Func<IGreeting, string, string, int>, which can’t be used with ExecuteGreetingFunc as is because it expects Func<IGreeting, TResult>.  Somehow we have to eliminate the two string parameters before we can use this with our existing method.  This is where we need to adapt AddName to match what ExecuteGreetingFunc expects, and we’ll do so in the following progression. 1: Func<IGreeting, string, string, int> -> Func<IGreeting, string, int> 2: Func<IGreeting, string, int> -> Func<IGreeting, int>   For the first step, we’ll create a method using the lambda syntax that will “eliminate” the last name parameter: 1: string lastNameToAdd = "Smith"; 2: //Func<IGreeting, string, string, int> -> Func<IGreeting, string, int> 3: Func<IGreeting, string, int> addName = (greetingService, firstName) => AddName(greetingService, firstName, lastNameToAdd); The new addName method gets us one step close to the signature we need.  Let’s say we’re going to call this in a loop to add several names, we’ll take the final step from Func<IGreeting, string, int> -> Func<IGreeting, int> in line as a lambda passed to ExecuteGreetingFunc like so: 1: List<string> firstNames = new List<string>() { "Bob", "John" }; 2: int aID; 3: foreach (string firstName in firstNames) 4: { 5: //Func<IGreeting, string, int> -> Func<IGreeting, int> 6: aID = ExecuteGreetingFunc<int>(greetingService => addName(greetingService, firstName)); 7: Console.WriteLine(GetGreeting(aID)); 8: } If for some reason you needed to break out the lambda on line 6 you could replace it with 1: aID = ExecuteGreetingFunc<int>(ApplyAddName(addName, firstName)); and use this method: 1: private static Func<IGreeting, int> ApplyAddName(Func<IGreeting, string, int> addName, string lastName) 2: { 3: return greetingService => addName(greetingService, lastName); 4: } Splitting out a lambda into its own method is useful both in this style of coding as well as LINQ queries to improve the debugging experience.  It is not strictly necessary to break apart the steps & functions as was shown above; the lambda in line 6 (of the foreach example) could include both the last name and first name instead of being composed of two functions.  The process demonstrated above is one of partially applying functions, this could have also been done with Currying (also see Dustin Campbell’s excellent post on Currying for the canonical curried add example).  Matthew Podwysocki also has some good posts explaining both Currying and partial application and a follow up post that further clarifies the difference between Currying and partial application.  In either technique the ultimate goal is to reduce the number of parameters passed to a function.  Currying makes it a single parameter passed at each step, where partial application allows one to use multiple parameters at a time as we’ve done here.  This technique isn’t for everyone or every problem, but can be extremely handy when you need to adapt a call to something you don’t control.

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• RIF PRD: Presentation syntax issues

  - by Charles Young

  Over Christmas I got to play a bit with the W3C RIF PRD and came across a few issues which I thought I would record for posterity. Specifically, I was working on a grammar for the presentation syntax using a GLR grammar parser tool (I was using the current CTP of ‘M’ (MGrammer) and Intellipad – I do so hope the MS guys don’t kill off M and Intellipad now they have dropped the other parts of SQL Server Modelling). I realise that the presentation syntax is non-normative and that any issues with it do not therefore compromise the standard. However, presentation syntax is useful in its own right, and it would be great to iron out any issues in a future revision of the standard. The main issues are actually not to do with the grammar at all, but rather with the ‘running example’ in the RIF PRD recommendation. I started with the code provided in Example 9.1. There are several discrepancies when compared with the EBNF rules documented in the standard. Broadly the problems can be categorised as follows: ·      Parenthesis mismatch – the wrong number of parentheses are used in various places. For example, in GoldRule, the RHS of the rule (the ‘Then’) is nested in the LHS (‘the If’). In NewCustomerAndWidgetRule, the RHS is orphaned from the LHS. Together with additional incorrect parenthesis, this leads to orphanage of UnknownStatusRule from the entire Document. ·      Invalid use of parenthesis in ‘Forall’ constructs. Parenthesis should not be used to enclose formulae. Removal of the invalid parenthesis gave me a feeling of inconsistency when comparing formulae in Forall to formulae in If. The use of parenthesis is not actually inconsistent in these two context, but in an If construct it ‘feels’ as if you are enclosing formulae in parenthesis in a LISP-like fashion. In reality, the parenthesis is simply being used to group subordinate syntax elements. The fact that an If construct can contain only a single formula as an immediate child adds to this feeling of inconsistency. ·      Invalid representation of compact URIs (CURIEs) in the context of Frame productions. In several places the URIs are not qualified with a namespace prefix (‘ex1:’). This conflicts with the definition of CURIEs in the RIF Datatypes and Built-Ins 1.0 document. Here are the productions: CURIE          ::= PNAME_LN                  | PNAME_NS PNAME_LN       ::= PNAME_NS PN_LOCAL PNAME_NS       ::= PN_PREFIX? ':' PN_LOCAL       ::= ( PN_CHARS_U | [0-9] ) ((PN_CHARS|'.')* PN_CHARS)? PN_CHARS       ::= PN_CHARS_U                  | '-' | [0-9] | #x00B7                  | [#x0300-#x036F] | [#x203F-#x2040] PN_CHARS_U     ::= PN_CHARS_BASE                  | '_' PN_CHARS_BASE ::= [A-Z] | [a-z] | [#x00C0-#x00D6] | [#x00D8-#x00F6]                  | [#x00F8-#x02FF] | [#x0370-#x037D] | [#x037F-#x1FFF]                  | [#x200C-#x200D] | [#x2070-#x218F] | [#x2C00-#x2FEF]                  | [#x3001-#xD7FF] | [#xF900-#xFDCF] | [#xFDF0-#xFFFD]                  | [#x10000-#xEFFFF] PN_PREFIX      ::= PN_CHARS_BASE ((PN_CHARS|'.')* PN_CHARS)? The more I look at CURIEs, the more my head hurts! The RIF specification allows prefixes and colons without local names, which surprised me. However, the CURIE Syntax 1.0 working group note specifically states that this form is supported…and then promptly provides a syntactic definition that seems to preclude it! However, on (much) deeper inspection, it appears that ‘ex1:’ (for example) is allowed, but would really represent a ‘fragment’ of the ‘reference’, rather than a prefix! Ouch! This is so completely ambiguous that it surely calls into question the whole CURIE specification.   In any case, RIF does not allow local names without a prefix. ·      Missing ‘External’ specifiers for built-in functions and predicates.  The EBNF specification enforces this for terms within frames, but does not appear to enforce (what I believe is) the correct use of External on built-in predicates. In any case, the running example only specifies ‘External’ once on the predicate in UnknownStatusRule. External() is required in several other places. ·      The List used on the LHS of UnknownStatusRule is comma-delimited. This is not supported by the EBNF definition. Similarly, the argument list of pred:list-contains is illegally comma-delimited. ·      Unnecessary use of conjunction around a single formula in DiscountRule. This is strictly legal in the EBNF, but redundant.   All the above issues concern the presentation syntax used in the running example. There are a few minor issues with the grammar itself. Note that Michael Kiefer stated in his paper “Rule Interchange Format: The Framework” that: “The presentation syntax of RIF … is an abstract syntax and, as such, it omits certain details that might be important for unambiguous parsing.” ·      The grammar cannot differentiate unambiguously between strategies and priorities on groups. A processor is forced to resolve this by detecting the use of IRIs and integers. This could easily be fixed in the grammar.   ·      The grammar cannot unambiguously parse the ‘->’ operator in frames. Specifically, ‘-’ characters are allowed in PN_LOCAL names and hence a parser cannot determine if ‘status->’ is (‘status’ ‘->’) or (‘status-’ ‘>’).   One way to fix this is to amend the PN_LOCAL production as follows: PN_LOCAL ::= ( PN_CHARS_U | [0-9] ) ((PN_CHARS|'.')* ((PN_CHARS)-('-')))? However, unilaterally changing the definition of this production, which is defined in the SPARQL Query Language for RDF specification, makes me uncomfortable. ·      I assume that the presentation syntax is case-sensitive. I couldn’t find this stated anywhere in the documentation, but function/predicate names do appear to be documented as being case-sensitive. ·      The EBNF does not specify whitespace handling. A couple of productions (RULE and ACTION_BLOCK) are crafted to enforce the use of whitespace. This is not necessary. It seems inconsistent with the rest of the specification and can cause parsing issues. In addition, the Const production exhibits whitespaces issues. The intention may have been to disallow the use of whitespace around ‘^^’, but any direct implementation of the EBNF will probably allow whitespace between ‘^^’ and the SYMSPACE. Of course, I am being a little nit-picking about all this. On the whole, the EBNF translated very smoothly and directly to ‘M’ (MGrammar) and proved to be fairly complete. I have encountered far worse issues when translating other EBNF specifications into usable grammars.   I can’t imagine there would be any difficulty in implementing the same grammar in Antlr, COCO/R, gppg, XText, Bison, etc. A general observation, which repeats a point made above, is that the use of parenthesis in the presentation syntax can feel inconsistent and un-intuitive.   It isn’t actually inconsistent, but I think the presentation syntax could be improved by adopting braces, rather than parenthesis, to delimit subordinate syntax elements in a similar way to so many programming languages. The familiarity of braces would communicate the structure of the syntax more clearly to people like me.  If braces were adopted, parentheses could be retained around ‘var (frame | ‘new()’) constructs in action blocks. This use of parenthesis feels very LISP-like, and I think that this is my issue. It’s as if the presentation syntax represents the deformed love-child of LISP and C. In some places (specifically, action blocks), parenthesis is used in a LISP-like fashion. In other places it is used like braces in C. I find this quite confusing. Here is a corrected version of the running example (Example 9.1) in compliant presentation syntax: Document(    Prefix( ex1 <http://example.com/2009/prd2> )    (* ex1:CheckoutRuleset *)  Group rif:forwardChaining (     (* ex1:GoldRule *)    Group 10 (      Forall ?customer such that And(?customer # ex1:Customer                                     ?customer[ex1:status->"Silver"])        (Forall ?shoppingCart such that ?customer[ex1:shoppingCart->?shoppingCart]           (If Exists ?value (And(?shoppingCart[ex1:value->?value]                                  External(pred:numeric-greater-than-or-equal(?value 2000))))            Then Do(Modify(?customer[ex1:status->"Gold"])))))      (* ex1:DiscountRule *)    Group (      Forall ?customer such that ?customer # ex1:Customer        (If Or( ?customer[ex1:status->"Silver"]                ?customer[ex1:status->"Gold"])         Then Do ((?s ?customer[ex1:shoppingCart-> ?s])                  (?v ?s[ex1:value->?v])                  Modify(?s [ex1:value->External(func:numeric-multiply (?v 0.95))]))))      (* ex1:NewCustomerAndWidgetRule *)    Group (      Forall ?customer such that And(?customer # ex1:Customer                                     ?customer[ex1:status->"New"] )        (If Exists ?shoppingCart ?item                   (And(?customer[ex1:shoppingCart->?shoppingCart]                        ?shoppingCart[ex1:containsItem->?item]                        ?item # ex1:Widget ) )         Then Do( (?s ?customer[ex1:shoppingCart->?s])                  (?val ?s[ex1:value->?val])                  (?voucher ?customer[ex1:voucher->?voucher])                  Retract(?customer[ex1:voucher->?voucher])                  Retract(?voucher)                  Modify(?s[ex1:value->External(func:numeric-multiply(?val 0.90))]))))      (* ex1:UnknownStatusRule *)    Group (      Forall ?customer such that ?customer # ex1:Customer        (If Not(Exists ?status                       (And(?customer[ex1:status->?status]                            External(pred:list-contains(List("New" "Bronze" "Silver" "Gold") ?status)) )))         Then Do( Execute(act:print(External(func:concat("New customer: " ?customer))))                  Assert(?customer[ex1:status->"New"]))))  ) )   I hope that helps someone out there :-)

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• How many developers before continuous integration becomes effective for us?

  - by Carnotaurus

  There is an overhead associated with continuous integration, e.g., set up, re-training, awareness activities, stoppage to fix "bugs" that turn out to be data issues, enforced separation of concerns programming styles, etc. At what point does continuous integration pay for itself? EDIT: These were my findings The set-up was CruiseControl.Net with Nant, reading from VSS or TFS. Here are a few reasons for failure, which have nothing to do with the setup: Cost of investigation: The time spent investigating whether a red light is due a genuine logical inconsistency in the code, data quality, or another source such as an infrastructure problem (e.g., a network issue, a timeout reading from source control, third party server is down, etc., etc.) Political costs over infrastructure: I considered performing an "infrastructure" check for each method in the test run. I had no solution to the timeout except to replace the build server. Red tape got in the way and there was no server replacement. Cost of fixing unit tests: A red light due to a data quality issue could be an indicator of a badly written unit test. So, data dependent unit tests were re-written to reduce the likelihood of a red light due to bad data. In many cases, necessary data was inserted into the test environment to be able to accurately run its unit tests. It makes sense to say that by making the data more robust then the test becomes more robust if it is dependent on this data. Of course, this worked well! Cost of coverage, i.e., writing unit tests for already existing code: There was the problem of unit test coverage. There were thousands of methods that had no unit tests. So, a sizeable amount of man days would be needed to create those. As this would be too difficult to provide a business case, it was decided that unit tests would be used for any new public method going forward. Those that did not have a unit test were termed 'potentially infra red'. An intestesting point here is that static methods were a moot point in how it would be possible to uniquely determine how a specific static method had failed. Cost of bespoke releases: Nant scripts only go so far. They are not that useful for, say, CMS dependent builds for EPiServer, CMS, or any UI oriented database deployment. These are the types of issues that occured on the build server for hourly test runs and overnight QA builds. I entertain that these to be unnecessary as a build master can perform these tasks manually at the time of release, esp., with a one man band and a small build. So, single step builds have not justified use of CI in my experience. What about the more complex, multistep builds? These can be a pain to build, especially without a Nant script. So, even having created one, these were no more successful. The costs of fixing the red light issues outweighed the benefits. Eventually, developers lost interest and questioned the validity of the red light. Having given it a fair try, I believe that CI is expensive and there is a lot of working around the edges instead of just getting the job done. It's more cost effective to employ experienced developers who do not make a mess of large projects than introduce and maintain an alarm system. This is the case even if those developers leave. It doesn't matter if a good developer leaves because processes that he follows would ensure that he writes requirement specs, design specs, sticks to the coding guidelines, and comments his code so that it is readable. All this is reviewed. If this is not happening then his team leader is not doing his job, which should be picked up by his manager and so on. For CI to work, it is not enough to just write unit tests, attempt to maintain full coverage, and ensure a working infrastructure for sizable systems. The bottom line: One might question whether fixing as many bugs before release is even desirable from a business prespective. CI involves a lot of work to capture a handful of bugs that the customer could identify in UAT or the company could get paid for fixing as part of a client service agreement when the warranty period expires anyway.

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• Refactoring Part 1 : Intuitive Investments

  - by Wes McClure

  Fear, it’s what turns maintaining applications into a nightmare.  Technology moves on, teams move on, someone is left to operate the application, what was green is now perceived brown.  Eventually the business will evolve and changes will need to be made.  The approach to those changes often dictates the long term viability of the application.  Fear of change, lack of passion and a lack of interest in understanding the domain often leads to a paranoia to do anything that doesn’t involve duct tape and bailing twine.  Don’t get me wrong, those have a place in the short term viability of a project but they don’t have a place in the long term.  Add to it “us versus them” in regards to the original team and those that maintain it, internal politics and other factors and you have a recipe for disaster.  This results in code that quickly becomes unmanageable.  Even the most clever of designs will eventually become sub optimal and debt will amount that exponentially makes changes difficult.  This is where refactoring comes in, and it’s something I’m very passionate about.  Refactoring is about improving the process whereby we make change, it’s an exponential investment in the process of change. Without it we will incur exponential complexity that halts productivity. Investments, especially in the long term, require intuition and reflection.  How can we tackle new development effectively via evolving the original design and paying off debt that has been incurred? The longer we wait to ask and answer this question, the more it will cost us.  Small requests don’t warrant big changes, but realizing when changes now will pay off in the long term, and especially in the short term, is valuable. I have done my fair share of maintaining applications and continuously refactoring as needed, but recently I’ve begun work on a project that hasn’t had much debt, if any, paid down in years.  This is the first in a series of blog posts to try to capture the process which is largely driven by intuition of smaller refactorings from other projects. Signs that refactoring could help: Testability How can decreasing test time not pay dividends? One of the first things I found was that a very important piece often takes 30+ minutes to test.  I can only imagine how much time this has cost historically, but more importantly the time it might cost in the coming weeks: I estimate at least 10-20 hours per person!  This is simply unacceptable for almost any situation.  As it turns out, about 6 hours of working with this part of the application and I was able to cut the time down to under 30 seconds!  In less than the lost time of one week, I was able to fix the problem for all future weeks! If we can’t test fast then we can’t change fast, nor with confidence. Code is used by end users and it’s also used by developers, consider your own needs in terms of the code base.  Adding logic to enable/disable features during testing can help decouple parts of an application and lead to massive improvements.  What exactly is so wrong about test code in real code?  Often, these become features for operators and sometimes end users.  If you cannot run an integration test within a test runner in your IDE, it’s time to refactor. Readability Are variables named meaningfully via a ubiquitous language? Is the code segmented functionally or behaviorally so as to minimize the complexity of any one area? Are aspects properly segmented to avoid confusion (security, logging, transactions, translations, dependency management etc) Is the code declarative (what) or imperative (how)?  What matters, not how.  LINQ is a great abstraction of the what, not how, of collection manipulation.  The Reactive framework is a great example of the what, not how, of managing streams of data. Are constants abstracted and named, or are they just inline? Do people constantly bitch about the code/design? If the code is hard to understand, it will be hard to change with confidence.  It’s a large undertaking if the original designers didn’t pay much attention to readability and as such will never be done to “completion.”  Make sure not to go over board, instead use this as you change an application, not in lieu of changes (like with testability). Complexity Simplicity will never be achieved, it’s highly subjective.  That said, a lot of code can be significantly simplified, tidy it up as you go.  Refactoring will often converge upon a simplification step after enough time, keep an eye out for this. Understandability In the process of changing code, one often gains a better understanding of it.  Refactoring code is a good way to learn how it works.  However, it’s usually best in combination with other reasons, in effect killing two birds with one stone.  Often this is done when readability is poor, in which case understandability is usually poor as well.  In the large undertaking we are making with this legacy application, we will be replacing it.  Therefore, understanding all of its features is important and this refactoring technique will come in very handy. Unused code How can deleting things not help? This is a freebie in refactoring, it’s very easy to detect with modern tools, especially in statically typed languages.  We have VCS for a reason, if in doubt, delete it out (ok that was cheesy)! If you don’t know where to start when refactoring, this is an excellent starting point! Duplication Do not pray and sacrifice to the anti-duplication gods, there are excellent examples where consolidated code is a horrible idea, usually with divergent domains.  That said, mediocre developers live by copy/paste.  Other times features converge and aren’t combined.  Tools for finding similar code are great in the example of copy/paste problems.  Knowledge of the domain helps identify convergent concepts that often lead to convergent solutions and will give intuition for where to look for conceptual repetition. 80/20 and the Boy Scouts It’s often said that 80% of the time 20% of the application is used most.  These tend to be the parts that are changed.  There are also parts of the code where 80% of the time is spent changing 20% (probably for all the refactoring smells above).  I focus on these areas any time I make a change and follow the philosophy of the Boy Scout in cleaning up more than I messed up.  If I spend 2 hours changing an application, in the 20%, I’ll always spend at least 15 minutes cleaning it or nearby areas. This gives a huge productivity edge on developers that don’t. Ironically after a short period of time the 20% shrinks enough that we don’t have to spend 80% of our time there and can move on to other areas.   Refactoring is highly subjective, never attempt to refactor to completion!  Learn to be comfortable with leaving one part of the application in a better state than others.  It’s an evolution, not a revolution.  These are some simple areas to look into when making changes and can help get one started in the process.  I’ve often found that refactoring is a convergent process towards simplicity that sometimes spans a few hours but often can lead to massive simplifications over the timespan of weeks and months of regular development.

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• Cloud to On-Premise Connectivity Patterns

  - by Rajesh Raheja

  Do you have a requirement to convert an Opportunity in Salesforce.com to an Order/Quote in Oracle E-Business Suite? Or maybe you want the creation of an Oracle RightNow Incident to trigger an on-premise Oracle E-Business Suite Service Request creation for RMA and Field Scheduling? If so, read on. In a previous blog post, I discussed integrating TO cloud applications, however the use cases above are the reverse i.e. receiving data FROM cloud applications (SaaS) TO on-premise applications/databases that sit behind a firewall. Oracle SOA Suite is assumed to be on-premise with with Oracle Service Bus as the mediation and virtualization layer. The main considerations for the patterns are are security i.e. shielding enterprise resources; and scalability i.e. minimizing firewall latency. Let me use an analogy to help visualize the patterns: the on-premise system is your home - with your most valuable possessions - and the SaaS app is your favorite on-line store which regularly ships (inbound calls) various types of parcels/items (message types/service operations). You need the items at home (on-premise) but want to safe guard against misguided elements of society (internet threats) who may masquerade as postal workers and vandalize property (denial of service?). Let's look at the patterns. Pattern: Pull from Cloud The on-premise system polls from the SaaS apps and picks up the message instead of having it delivered. This may be done using Oracle RightNow Object Query Language or SOAP APIs. This is particularly suited for certain integration approaches wherein messages are trickling in, can be centralized and batched e.g. retrieving event notifications on an hourly schedule from the Oracle Messaging Service. To compare this pattern with the home analogy, you are avoiding any deliveries to your home and instead go to the post office/UPS/Fedex store to pick up your parcel. Every time. Pros: On-premise assets not exposed to the Internet, firewall issues avoided by only initiating outbound connections Cons: Polling mechanisms may affect performance, may not satisfy near real-time requirements Pattern: Open Firewall Ports The on-premise system exposes the web services that needs to be invoked by the cloud application. This requires opening up firewall ports, routing calls to the appropriate internal services behind the firewall. Fusion Applications uses this pattern, and auto-provisions the services on the various virtual hosts to secure the topology. This works well for service integration, but may not suffice for large volume data integration. Using the home analogy, you have now decided to receive parcels instead of going to the post office every time. A door mail slot cut out allows the postman can drop small parcels, but there is still concern about cutting new holes for larger packages. Pros: optimal pattern for near real-time needs, simpler administration once the service is provisioned Cons: Needs firewall ports to be opened up for new services, may not suffice for batch integration requiring direct database access Pattern: Virtual Private Networking The on-premise network is "extended" to the cloud (or an intermediary on-demand / managed service offering) using Virtual Private Networking (VPN) so that messages are delivered to the on-premise system in a trusted channel. Using the home analogy, you entrust a set of keys with a neighbor or property manager who receives the packages, and then drops it inside your home. Pros: Individual firewall ports don't need to be opened, more suited for high scalability needs, can support large volume data integration, easier management of one connection vs a multitude of open ports Cons: VPN setup, specific hardware support, requires cloud provider to support virtual private computing Pattern: Reverse Proxy / API Gateway The on-premise system uses a reverse proxy "API gateway" software on the DMZ to receive messages. The reverse proxy can be implemented using various mechanisms e.g. Oracle API Gateway provides firewall and proxy services along with comprehensive security, auditing, throttling benefits. If a firewall already exists, then Oracle Service Bus or Oracle HTTP Server virtual hosts can provide reverse proxy implementations on the DMZ. Custom built implementations are also possible if specific functionality (such as message store-n-forward) is needed. In the home analogy, this pattern sits in between cutting mail slots and handing over keys. Instead, you install (and maintain) a mailbox in your home premises outside your door. The post office delivers the parcels in your mailbox, from where you can securely retrieve it. Pros: Very secure, very flexible Cons: Introduces a new software component, needs DMZ deployment and management Pattern: On-Premise Agent (Tunneling) A light weight "agent" software sits behind the firewall and initiates the communication with the cloud, thereby avoiding firewall issues. It then maintains a bi-directional connection either with pull or push based approaches using (or abusing, depending on your viewpoint) the HTTP protocol. Programming protocols such as Comet, WebSockets, HTTP CONNECT, HTTP SSH Tunneling etc. are possible implementation options. In the home analogy, a resident receives the parcel from the postal worker by opening the door, however you still take precautions with chain locks and package inspections. Pros: Light weight software, IT doesn't need to setup anything Cons: May bypass critical firewall checks e.g. virus scans, separate software download, proliferation of non-IT managed software Conclusion The patterns above are some of the most commonly encountered ones for cloud to on-premise integration. Selecting the right pattern for your project involves looking at your scalability needs, security restrictions, sync vs asynchronous implementation, near real-time vs batch expectations, cloud provider capabilities, budget, and more. In some cases, the basic "Pull from Cloud" may be acceptable, whereas in others, an extensive VPN topology may be well justified. For more details on the Oracle cloud integration strategy, download this white paper.

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• Cloud to On-Premise Connectivity Patterns

  - by Rajesh Raheja

  Do you have a requirement to convert an Opportunity in Salesforce.com to an Order/Quote in Oracle E-Business Suite? Or maybe you want the creation of an Oracle RightNow Incident to trigger an on-premise Oracle E-Business Suite Service Request creation for RMA and Field Scheduling? If so, read on. In a previous blog post, I discussed integrating TO cloud applications, however the use cases above are the reverse i.e. receiving data FROM cloud applications (SaaS) TO on-premise applications/databases that sit behind a firewall. Oracle SOA Suite is assumed to be on-premise with with Oracle Service Bus as the mediation and virtualization layer. The main considerations for the patterns are are security i.e. shielding enterprise resources; and scalability i.e. minimizing firewall latency. Let me use an analogy to help visualize the patterns: the on-premise system is your home - with your most valuable possessions - and the SaaS app is your favorite on-line store which regularly ships (inbound calls) various types of parcels/items (message types/service operations). You need the items at home (on-premise) but want to safe guard against misguided elements of society (internet threats) who may masquerade as postal workers and vandalize property (denial of service?). Let's look at the patterns. Pattern: Pull from Cloud The on-premise system polls from the SaaS apps and picks up the message instead of having it delivered. This may be done using Oracle RightNow Object Query Language or SOAP APIs. This is particularly suited for certain integration approaches wherein messages are trickling in, can be centralized and batched e.g. retrieving event notifications on an hourly schedule from the Oracle Messaging Service. To compare this pattern with the home analogy, you are avoiding any deliveries to your home and instead go to the post office/UPS/Fedex store to pick up your parcel. Every time. Pros: On-premise assets not exposed to the Internet, firewall issues avoided by only initiating outbound connections Cons: Polling mechanisms may affect performance, may not satisfy near real-time requirements Pattern: Open Firewall Ports The on-premise system exposes the web services that needs to be invoked by the cloud application. This requires opening up firewall ports, routing calls to the appropriate internal services behind the firewall. Fusion Applications uses this pattern, and auto-provisions the services on the various virtual hosts to secure the topology. This works well for service integration, but may not suffice for large volume data integration. Using the home analogy, you have now decided to receive parcels instead of going to the post office every time. A door mail slot cut out allows the postman can drop small parcels, but there is still concern about cutting new holes for larger packages. Pros: optimal pattern for near real-time needs, simpler administration once the service is provisioned Cons: Needs firewall ports to be opened up for new services, may not suffice for batch integration requiring direct database access Pattern: Virtual Private Networking The on-premise network is "extended" to the cloud (or an intermediary on-demand / managed service offering) using Virtual Private Networking (VPN) so that messages are delivered to the on-premise system in a trusted channel. Using the home analogy, you entrust a set of keys with a neighbor or property manager who receives the packages, and then drops it inside your home. Pros: Individual firewall ports don't need to be opened, more suited for high scalability needs, can support large volume data integration, easier management of one connection vs a multitude of open ports Cons: VPN setup, specific hardware support, requires cloud provider to support virtual private computing Pattern: Reverse Proxy / API Gateway The on-premise system uses a reverse proxy "API gateway" software on the DMZ to receive messages. The reverse proxy can be implemented using various mechanisms e.g. Oracle API Gateway provides firewall and proxy services along with comprehensive security, auditing, throttling benefits. If a firewall already exists, then Oracle Service Bus or Oracle HTTP Server virtual hosts can provide reverse proxy implementations on the DMZ. Custom built implementations are also possible if specific functionality (such as message store-n-forward) is needed. In the home analogy, this pattern sits in between cutting mail slots and handing over keys. Instead, you install (and maintain) a mailbox in your home premises outside your door. The post office delivers the parcels in your mailbox, from where you can securely retrieve it. Pros: Very secure, very flexible Cons: Introduces a new software component, needs DMZ deployment and management Pattern: On-Premise Agent (Tunneling) A light weight "agent" software sits behind the firewall and initiates the communication with the cloud, thereby avoiding firewall issues. It then maintains a bi-directional connection either with pull or push based approaches using (or abusing, depending on your viewpoint) the HTTP protocol. Programming protocols such as Comet, WebSockets, HTTP CONNECT, HTTP SSH Tunneling etc. are possible implementation options. In the home analogy, a resident receives the parcel from the postal worker by opening the door, however you still take precautions with chain locks and package inspections. Pros: Light weight software, IT doesn't need to setup anything Cons: May bypass critical firewall checks e.g. virus scans, separate software download, proliferation of non-IT managed software Conclusion The patterns above are some of the most commonly encountered ones for cloud to on-premise integration. Selecting the right pattern for your project involves looking at your scalability needs, security restrictions, sync vs asynchronous implementation, near real-time vs batch expectations, cloud provider capabilities, budget, and more. In some cases, the basic "Pull from Cloud" may be acceptable, whereas in others, an extensive VPN topology may be well justified. For more details on the Oracle cloud integration strategy, download this white paper.

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• Telerik Releases a new Visual Entity Designer

  Love LINQ to SQL but are concerned that it is a second class citizen? Need to connect to more databases other than SQL Server? Think that the Entity Framework is too complex? Want a domain model designer for data access that is easy, yet powerful? Then the Telerik Visual Entity Designer is for you. Built on top of Telerik OpenAccess ORM, a very mature and robust product, Teleriks Visual Entity Designer is a new way to build your domain model that is very powerful and also real easy to use. How easy? Ill show you here. First Look: Using the Telerik Visual Entity Designer To get started, you need to install the Telerik OpenAccess ORM Q1 release for Visual Studio 2008 or 2010. You dont need to use any of the Telerik OpenAccess wizards, designers, or using statements. Just right click on your project and select Add|New Item from the context menu. Choose Telerik OpenAccess Domain Model from the Visual Studio project templates. (Note to existing OpenAccess users, dont run the Enable ORM wizard or any other OpenAccess menu unless you are building OpenAccess Entities.) You will then have to specify the database backend (SQL Server, SQL Azure, Oracle, MySQL, etc) and connection. After you establish your connection, select the database objects you want to add to your domain model. You can also name your model, by default it will be NameofyourdatabaseEntityDiagrams. You can click finish here if you are comfortable, or tweak some advanced settings. Many users of domain models like to add prefixes and suffixes to classes, fields, and properties as well as handle pluralization. I personally accept the defaults, however, I hate how DBAs force underscores on me, so I click on the option to remove them. You can also tweak your namespace, mapping options, and define your own code generation template to gain further control over the outputted code. This is a very powerful feature, but for now, I will just accept the defaults.   When we click finish, you can see your domain model as a file with the .rlinq extension in the Solution Explorer. You can also bring up the visual designer to view or further tweak your model by double clicking on the model in the Solution Explorer.  Time to use the model! Writing a LINQ Query Programming against the domain model is very simple using LINQ. Just set a reference to the model (line 12 of the code below) and write a standard LINQ statement (lines 14-16).  (OpenAccess users: notice the you dont need any using statements for OpenAccess or an IObjectScope, just raw LINQ against your model.) 1: using System; 2: using System.Linq; 3: //no need for anOpenAccess using statement 4:   5: namespace ConsoleApplication3 6: { 7: class Program 8: { 9: static void Main(string[] args) 10: { 11: //a reference tothe data context 12: NorthwindEntityDiagrams dat = new NorthwindEntityDiagrams(); 13: //LINQ Statement 14: var result = from c in dat.Customers 15: where c.Country == "Germany" 16: select c; 17:   18: //Print out the company name 19: foreach (var cust in result) 20: { 21: Console.WriteLine("CompanyName: " + cust.CompanyName); 22: } 23: //keep the consolewindow open 24: Console.Read(); 25: } 26: } 27: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Lines 19-24 loop through the result of our LINQ query and displays the results. Thats it! All of the super powerful features of OpenAccess are available to you to further enhance your experience, however, in most cases this is all you need. In future posts I will show how to use the Visual Designer with some other scenarios. Stay tuned. Enjoy! Technorati Tags: Telerik,OpenAccess,LINQ Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Scripting Part 1

  - by rbishop

  Dynamic Scripting is a large topic, so let me get a couple of things out of the way first. If you aren't familiar with JavaScript, I can suggest CodeAcademy's JavaScript series. There are also many other websites and books that cover JavaScript from every possible angle.The second thing we need to deal with is JavaScript as a programming language versus a JavaScript environment running in a web browser. Many books, tutorials, and websites completely blur these two together but they are in fact completely separate. What does this really mean in relation to DRM? Since DRM isn't a web browser, there are no document, window, history, screen, or location objects. There are no events like mousedown or click. Trying to call alert('hello!') in DRM will just cause an error. Those concepts are all related to an HTML document (web page) and are part of the Browser Object Model or Document Object Model. DRM has its own object model that exposes DRM-related objects. In practice, feel free to use those sorts of tutorials or practice within your browser; Many of the concepts are directly translatable to writing scripts in DRM. Just don't try to call document.getElementById in your property definition!I think learning by example tends to work the best, so let's try getting a list of all the unique property values for a given node and its children. var uniqueValues = {}; var childEnumerator = node.GetChildEnumerator(); while(childEnumerator.MoveNext()) { var propValue = childEnumerator.GetCurrent().PropValue("Custom.testpropstr1"); print(propValue); if(propValue != null && propValue != '' && !uniqueValues[propValue]) uniqueValues[propValue] = true; } var result = ''; for(var value in uniqueValues){ result += "Found value " + value + ","; } return result;  Now lets break this down piece by piece. var uniqueValues = {}; This declares a variable and initializes it as a new empty Object. You could also have written var uniqueValues = new Object(); Why use an object here? JavaScript objects can also function as a list of keys and we'll use that later to store each property value as a key on the object. var childEnumerator = node.GetChildEnumerator(); while(childEnumerator.MoveNext()) { This gets an enumerator for the node's children. The enumerator allows us to loop through the children one by one. If we wanted to get a filtered list of children, we would instead use ChildrenWith(). When we reach the end of the child list, the enumerator will return false for MoveNext() and that will stop the loop. var propValue = childEnumerator.GetCurrent().PropValue("Custom.testpropstr1"); print(propValue); if(propValue != null && propValue != '' && !uniqueValues[propValue]) uniqueValues[propValue] = true; } This gets the node the enumerator is currently pointing at, then calls PropValue() on it to get the value of a property. We then make sure the prop value isn't null or the empty string, then we make sure the value doesn't already exist as a key. Assuming it doesn't we add it as a key with a value (true in this case because it makes checking for an existing value faster when the value exists). A quick word on the print() function. When viewing the prop grid, running an export, or performing normal DRM operations it does nothing. If you have a lot of print() calls with complicated arguments it can slow your script down slightly, but otherwise has no effect. But when using the script editor, all the output of print() will be shown in the Warnings area. This gives you an extremely useful debugging tool to see what exactly a script is doing. var result = ''; for(var value in uniqueValues){ result += "Found value " + value + ","; } return result; Now we build a string by looping through all the keys in uniqueValues and adding that value to our string. The last step is to simply return the result. Hopefully this small example demonstrates some of the core Dynamic Scripting concepts. Next time, we can try checking for node references in other hierarchies to see if they are using duplicate property values.

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• Trying to detect collision between two polygons using Separating Axis Theorem

  - by Holly

  The only collision experience i've had was with simple rectangles, i wanted to find something that would allow me to define polygonal areas for collision and have been trying to make sense of SAT using these two links Though i'm a bit iffy with the math for the most part i feel like i understand the theory! Except my implementation somewhere down the line must be off as: (excuse the hideous font) As mentioned above i have defined a CollisionPolygon class where most of my theory is implemented and then have a helper class called Vect which was meant to be for Vectors but has also been used to contain a vertex given that both just have two float values. I've tried stepping through the function and inspecting the values to solve things but given so many axes and vectors and new math to work out as i go i'm struggling to find the erroneous calculation(s) and would really appreciate any help. Apologies if this is not suitable as a question! CollisionPolygon.java: package biz.hireholly.gameplay; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import biz.hireholly.gameplay.Types.Vect; public class CollisionPolygon { Paint paint; private Vect[] vertices; private Vect[] separationAxes; CollisionPolygon(Vect[] vertices){ this.vertices = vertices; //compute edges and separations axes separationAxes = new Vect[vertices.length]; for (int i = 0; i < vertices.length; i++) { // get the current vertex Vect p1 = vertices[i]; // get the next vertex Vect p2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; // subtract the two to get the edge vector Vect edge = p1.subtract(p2); // get either perpendicular vector Vect normal = edge.perp(); // the perp method is just (x, y) => (-y, x) or (y, -x) separationAxes[i] = normal; } paint = new Paint(); paint.setColor(Color.RED); } public void draw(Canvas c, int xPos, int yPos){ for (int i = 0; i < vertices.length; i++) { Vect v1 = vertices[i]; Vect v2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; c.drawLine( xPos + v1.x, yPos + v1.y, xPos + v2.x, yPos + v2.y, paint); } } /* consider changing to a static function */ public boolean intersects(CollisionPolygon p){ // loop over this polygons separation exes for (Vect axis : separationAxes) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // loop over the other polygons separation axes Vect[] sepAxesOther = p.getSeparationAxes(); for (Vect axis : sepAxesOther) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // if we get here then we know that every axis had overlap on it // so we can guarantee an intersection return true; } /* Note projections wont actually be acurate if the axes aren't normalised * but that's not necessary since we just need a boolean return from our * intersects not a Minimum Translation Vector. */ private Vect minMaxProjection(Vect axis) { float min = axis.dot(vertices[0]); float max = min; for (int i = 1; i < vertices.length; i++) { float p = axis.dot(vertices[i]); if (p < min) { min = p; } else if (p > max) { max = p; } } Vect minMaxProj = new Vect(min, max); return minMaxProj; } public Vect[] getSeparationAxes() { return separationAxes; } public Vect[] getVertices() { return vertices; } } Vect.java: package biz.hireholly.gameplay.Types; /* NOTE: Can also be used to hold vertices! Projections, coordinates ect */ public class Vect{ public float x; public float y; public Vect(float x, float y){ this.x = x; this.y = y; } public Vect perp() { return new Vect(-y, x); } public Vect subtract(Vect other) { return new Vect(x - other.x, y - other.y); } public boolean overlap(Vect other) { if( other.x <= y || other.y >= x){ return true; } return false; } /* used specifically for my SAT implementation which i'm figuring out as i go, * references for later.. * http://www.gamedev.net/page/resources/_/technical/game-programming/2d-rotated-rectangle-collision-r2604 * http://www.codezealot.org/archives/55 */ public float scalarDotProjection(Vect other) { //multiplier = dot product / length^2 float multiplier = dot(other) / (x*x + y*y); //to get the x/y of the projection vector multiply by x/y of axis float projX = multiplier * x; float projY = multiplier * y; //we want to return the dot product of the projection, it's meaningless but useful in our SAT case return dot(new Vect(projX,projY)); } public float dot(Vect other){ return (other.x*x + other.y*y); } }

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• A*, Tile costs and heuristic; How to approach

  - by Kevin Toet

  I'm doing exercises in tile games and AI to improve my programming. I've written a highly unoptimised pathfinder that does the trick and a simple tile class. The first problem i ran into was that the heuristic was rounded to int's which resulted in very straight paths. Resorting a Euclidian Heuristic seemed to fixed it as opposed to use the Manhattan approach. The 2nd problem I ran into was when i tried added tile costs. I was hoping to use the value's of the flags that i set on the tiles but the value's were too small to make the pathfinder consider them a huge obstacle so i increased their value's but that breaks the flags a certain way and no paths were found anymore. So my questions, before posting the code, are: What am I doing wrong that the Manhatten heuristic isnt working? What ways can I store the tile costs? I was hoping to (ab)use the enum flags for this The path finder isnt considering the chance that no path is available, how do i check this? Any code optimisations are welcome as I'd love to improve my coding. public static List<Tile> FindPath( Tile startTile, Tile endTile, Tile[,] map ) { return FindPath( startTile, endTile, map, TileFlags.WALKABLE ); } public static List<Tile> FindPath( Tile startTile, Tile endTile, Tile[,] map, TileFlags acceptedFlags ) { List<Tile> open = new List<Tile>(); List<Tile> closed = new List<Tile>(); open.Add( startTile ); Tile tileToCheck; do { tileToCheck = open[0]; closed.Add( tileToCheck ); open.Remove( tileToCheck ); for( int i = 0; i < tileToCheck.neighbors.Count; i++ ) { Tile tile = tileToCheck.neighbors[ i ]; //has the node been processed if( !closed.Contains( tile ) && ( tile.flags & acceptedFlags ) != 0 ) { //Not in the open list? if( !open.Contains( tile ) ) { //Set G int G = 10; G += tileToCheck.G; //Set Parent tile.parentX = tileToCheck.x; tile.parentY = tileToCheck.y; tile.G = G; //tile.H = Math.Abs(endTile.x - tile.x ) + Math.Abs( endTile.y - tile.y ) * 10; //TODO omg wtf and other incredible stories tile.H = Vector2.Distance( new Vector2( tile.x, tile.y ), new Vector2(endTile.x, endTile.y) ); tile.Cost = tile.G + tile.H + (int)tile.flags; //Calculate H; Manhattan style open.Add( tile ); } //Update the cost if it is else { int G = 10;//cost of going to non-diagonal tiles G += map[ tile.parentX, tile.parentY ].G; //If this path is shorter (G cost is lower) then change //the parent cell, G cost and F cost. if ( G < tile.G ) //if G cost is less, { tile.parentX = tileToCheck.x; //change the square's parent tile.parentY = tileToCheck.y; tile.G = G;//change the G cost tile.Cost = tile.G + tile.H + (int)tile.flags; // add terrain cost } } } } //Sort costs open = open.OrderBy( o => o.Cost).ToList(); } while( tileToCheck != endTile ); closed.Reverse(); List<Tile> validRoute = new List<Tile>(); Tile currentTile = closed[ 0 ]; validRoute.Add( currentTile ); do { //Look up the parent of the current cell. currentTile = map[ currentTile.parentX, currentTile.parentY ]; currentTile.renderer.material.color = Color.green; //Add tile to list validRoute.Add( currentTile ); } while ( currentTile != startTile ); validRoute.Reverse(); return validRoute; } And my Tile class: [Flags] public enum TileFlags: int { NONE = 0, DIRT = 1, STONE = 2, WATER = 4, BUILDING = 8, //handy WALKABLE = DIRT | STONE | NONE, endofenum } public class Tile : MonoBehaviour { //Tile Properties public int x, y; public TileFlags flags = TileFlags.DIRT; public Transform cachedTransform; //A* properties public int parentX, parentY; public int G; public float Cost; public float H; public List<Tile> neighbors = new List<Tile>(); void Awake() { cachedTransform = transform; } }

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