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• Attunity Oracle CDC Solution for SSIS - Beta

  We in no way work for Attunity but we were asked to test drive a beta version of their Oracle CDC solution for SSIS.  Everybody should know that moving more data than you need to takes too much time and uses resources that may better be employed doing something else.  Change data Capture is a technology that is designed to help you identify only the data that has had something done to it and you can therefore move only what is needed.  Microsoft have implemented this exact functionality into SQL server 2008 and I really like it there.  Attunity though are doing it on Oracle. DISCLAIMER: This is a BETA release and some of the parts are a bit ugly/difficult to work with.  The idea though is definitely right and the product once working does exactly what it says on the tin.  They have always been helpful to me when I have had a problem with the product and if that continues then beta testing pain should be eased somewhat. In due course I am going to be doing some videos around me using the product.  If you use Oracle and SSIS then give it a go. Here is their product description.   Attunity is a Microsoft SQL Server technology partner and the creator of the Microsoft Connectors for Oracle and Teradata, currently available in SQL Server 2008 Enterprise Edition. Attunity released a beta version of the Attunity Oracle-CDC for SSIS, a product that integrates continually changing Oracle data into SSIS, efficiently and in real-time. Attunity designed the product and integrated it into SSIS to create the simple creation of change data capture (CDC) solutions, accelerate implementation time, and reduce resources and costs. They also utilize log-based CDC so the solution has minimal impact on the Oracle source system. You can use the product to implement enterprise-class data replication, synchronization, and real-time business intelligence (BI) and data warehousing projects, quickly and efficiently, leveraging their existing SQL Server investments and resource skills. Attunity architected the product specifically for the Microsoft SSIS developer community and the product is available for both SQL Server 2005 and SQL Server 2008. It offers the following key capabilities: · Log-based, non-intrusive Oracle CDC · Full integration into SSIS and the Business Intelligence Developer Studio · Automatic generation of SSIS packages for CDC as well as full-loads of Oracle data · Filtering of Oracle tables and columns at the source · Monitoring and control of CDC processing Click to learn more and download the beta.

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• It's called College.

  - by jeffreyabecker

  Today I saw yet another 'GUID vs int as your primary key' article. Like most of the ones I've read this was filled with technical misrepresentations and out-right fallices. Chef's famous line that "There's a time and a place for everything children" applies here. GUIDs have distinct advantages and disadvantages which should be considered when choosing a data type for the primary key. Fallacy 1: "Its easier" An integer data type(tinyint, smallint, int, bigint) is a better artifical key than a GUID because its easier to remember. I'm a firm believer that your artifical primary keys should be opaque gibberish. PK's are an implementation detail which should never be exposed to the user or relied on for business logic. If you want things to come back in an order, add and ORDER BY clause and SortOrder fields. If you want a human-usable look-up add a business key with a unique constraint. If you want to know what order things were inserted into a table add a timestamp. Fallacy 2: "Size Matters" For many applications, the size of the artifical primary key is going to be irrelevant. The particular article which kicked this post off stated repeatedly that joining against an int has better performance than joining against a GUID. In computer science the performance of your algorithm is always a function of the number of data points. This still holds true for databases. Unless your table is very large, the performance difference between an int and a guid probably isnt going to be mesurable let alone noticeable. My personal experience is that the performance becomes an issue when you start having billions of rows in the table. At this point, you should probably start looking to move from int to bigint so the effective space/performance gain isnt as much as you'd think. GUID Advantages: Insert-ability / Mergeability: You can reliably insert guids into tables without key collisions. Database Independence: Saving entities to the database often requires knowing ids. With identity based ids the id must be selected back after every insert. GUIDs can be generated application-side allowing much faster inserts. GUID Disadvantages: Generatability: You can calculate the next id for an integer pk pretty easily in your head but will need a program to generate GUIDs. Solution: "Select top 100 newid() from sysobjects" Fragmentation: most GUID generation algorithms generate pseudo random GUIDs. This can cause inserts into the middle of your clustered index. Solutions: add a default of newsequentialid() or use GuidComb in NHibernate.

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• Basic web architecture : Perl -> PHP

  - by Sunny Jim

  This is an architecture question. If there is a better forum, please redirect me. Apologies in advance. Essentially every website is built around a relational database, right? When a user uploads form data, that data is stored in a table. The problem is that the table structure(s) need to be modified whenever the website form is modified. Although I understand that modern web frameworks work around this problem by automatically building forms based on the table structure. For the last 20 years, I have been building websites using Perl. When I first encountered this problem, the easiest solution was to save serialized Perl objects as data BLOBS. After XML's introduction, this solution worked even better because XML is so effective for representing arbitrary data. This approach is consistent with the original Perl principles of Hubris, Laziness, and Impatience and I'm pretty committed to it. Obviously, the biggest drawback is that this solution locks me into the Perl interpreter. So instead, I've just completed a prototype of a universal RDB table. The prototype is written in Perl but porting it to PHP will be a good chance to develop those skills. The principal is based on the XML::Dumper module, which converts arbitrary Perl data structures into uniform XML. With my approach, each XML node is stored as a table record. I underestimated this undertaking and rolled something up myself. But the effort allows me to discuss the basic design instead of implementation details. As mentioned, I'm pretty committed to this approach of using flexible data structures. It's been successfully deployed on many websites, large, and complex. But are there any drawbacks I've overlooked? I rolled my own. Are other people taking a similar approach to their data? What kinds of solutions are available? I have not abandoned my dream of eventually contributing something useful to the worldwide community. In order to proceed, the next step would be peer review. How does one pursue that effort? Thanks! -Jim

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• Stagnating in programming

  - by Coder

  Time after time this question came up in my mind, but up until today I wasn't thinking about it much. I have been programming for maybe around 8 years now, and for the last two years it seems I'm not as keen to pick up new technologies anymore. Maybe that's a burnout or something, but I'd say it's experience and what I like, that's stopping me from running after the latest and greatest. I'm C++ developer, by this I mean, I love close to metal programming. I have no problems tracing problems through assembly, using tools like WinDbg or HexView. When I use constructs, I think about how they are realized underneath, how the bits are set and unset under the hood. I love battling with complex threading problems and doing everything hardcore way, even by hand if the regular solutions seem half baked. But I also love the C++0x stuff, and use it a lot. And all C++ code as long as it's not cumbersome compared to C counterparts, sometimes I also fall back to sort of "Super C" if the C++ way is ugly. And then there are all other developers who seem to be way more forward looking, .Net 4.0 MVC, WPF, all those Microsoft X#s, LINQ languages, XML and XSLT, mobile devices and so on. I have done a considerable amount of .NET, SQL, ASPX programming, but the further I go, the less I want to try those technologies. Is that bad? Almost every day I hear people saying that managed code is the only way forward, WPF is the way to go. I hear that C++ is godawful, and you can't code anything in it that's somewhat stable. But I don't buy it. With the experience I have, and the knowledge of how native code is compiled and executes, I can say I find it extremely rare that C++ code is unstable, or leaks, or causes crashes that takes more than 30 seconds to identify and fix. And to tell the truth, I've seen enough problems with other "cool" languages that I'd say C++ is even more stable and production proof than the safe languages, at least for me. The only thing that scares me in C++ is new frameworks, I don't trust them, and I use them extra sparingly. STL - yes, ATL - very sparingly, everything else... Well, not very keen on it. Most huge problems I've ran into, all were related to frameworks, not the language itself. Some overrided operator here, bad hierarchy there, poor class design here, mystical castings there. Other than that, C/C++ (yes, I use them together) still seems a very controlled and stable way to develop applications. Am I stagnating? Should I switch a profession, or force myself in all that marketing hype? Are there more developers who feel the same way?

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• Should CSS be listed on your resume under Languages?

  - by Sandeepan Nath

  I have some doubts like Whether CSS should be put under Languages or not? Although Wikipedia says Cascading Style Sheets (CSS) is a style sheet language ... But do they write CSS under the languages section of the resume, along with PHP, etc? Similarly what about HTML? I have some doubt and I don't want to sound like someone who is not aware of the trends. Just to give an example, currently I have the following languages,frameworks, technologies, etc. listed under the "Technical Expertise" section of my resume - Technical Expertise * Languages - Proficient - PHP 5, Javascript, HTML ?*,CSS ?*,Sass ?*. Beginner - Linux Bash. * Databases - MySQL 5. * Technologies - AJAX. * Frameworks/Libraries - Symfony, jQuery. * CMSes - Wordpress. Although my domain is Web-development/design, I welcome domain-agnostic answers which can provide some generic ideas/reasoning. I have seen, a lot of people messing up these sections (even more serious than my doubts :) ), putting things under wrong sub-headings and thus putting a big question mark on their understanding of those things. I don't know much about XML, Comet Technology etc. Considering those are included too, What things should be put under Languages? E.g. Should CSS be put under Languages? Please give some reasoning to support your views. Where should the others (XML, Comet, cURL etc. ) be put? I welcome some examples of how you put it. Or do you have an additional Keywords section where you write all the unsortables ? Considering a set of standards like W3C standards, etc. do you have a standards sub-heading? I guess I have put the contents of other sections Okay. But do let me know about your ideas and reasoning. After all, I understand there may not be a single answer to this, but let's see what is the trend. Thanks Updates Further, do you mention design patters you have used? Web Services etc.? Where do you mention SOAP, XML etc...

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• Is it a bug or a task when something doesn't work, yet, in development process

  - by Patkos Csaba

  We usually have this dilemma in our team. Sometimes, in order to implement a task or a story we find out that the system must be in a specific state. For example, a specific system configuration has to be made beforehand. The task / story can be completed and it is working as specified on it with the proper configuration in place. Note that the configuration is not directly related with the task. Next, we have to create a new ... ??? ... something for the process of generating that configuration file. This is where the problems appear. Some say that it is a bug others say it is a task or an extra feature. So, where is the limit between bugs and tasks in the development phase? Should we even consider something a bug if all the tasks are working as stated in their definitions? Can a thing be considered a bug because one compares it to the current (unstable) state of the system? Short example: A feature requires configuring a communication service for a specific operation. In the process of the implementation the team discovers that the service requires the hostnames of the pears to be resolvable to an IP address. The team adds the hostnames to the DNS server (or hosts files) and continues implementing the required feature. After the initial feature is working, a question is risen. Should the sysadmin configure the DNS or hosts file or should our application do it automatically? An automatic solution is possible. So a decision is made to implement it. ... here start the discussions ... is this a bug or an extra feature / task? PS: I know that I mixed feature / task / story in the question. It is intentional. I am interested in separating bugs from the rest. Doesn't matter what the rest means in a particular case.

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• What are the software design essentials? [closed]

  - by Craig Schwarze

  I've decided to create a 1 page "cheat sheet" of essential software design principles for my programmers. It doesn't explain the principles in any great depth, but is simply there as a reference and a reminder. Here's what I've come up with - I would welcome your comments. What have I left out? What have I explained poorly? What is there that shouldn't be? Basic Design Principles The Principle of Least Surprise – your solution should be obvious, predictable and consistent. Keep It Simple Stupid (KISS) - the simplest solution is usually the best one. You Ain’t Gonna Need It (YAGNI) - create a solution for the current problem rather than what might happen in the future. Don’t Repeat Yourself (DRY) - rigorously remove duplication from your design and code. Advanced Design Principles Program to an interface, not an implementation – Don’t declare variables to be of a particular concrete class. Rather, declare them to an interface, and instantiate them using a creational pattern. Favour composition over inheritance – Don’t overuse inheritance. In most cases, rich behaviour is best added by instantiating objects, rather than inheriting from classes. Strive for loosely coupled designs – Minimise the interdependencies between objects. They should be able to interact with minimal knowledge of each other via small, tightly defined interfaces. Principle of Least Knowledge – Also called the “Law of Demeter”, and is colloquially summarised as “Only talk to your friends”. Specifically, a method in an object should only invoke methods on the object itself, objects passed as a parameter to the method, any object the method creates, any components of the object. SOLID Design Principles Single Responsibility Principle – Each class should have one well defined purpose, and only one reason to change. This reduces the fragility of your code, and makes it much more maintainable. Open/Close Principle – A class should be open to extension, but closed to modification. In practice, this means extracting the code that is most likely to change to another class, and then injecting it as required via an appropriate pattern. Liskov Substitution Principle – Subtypes must be substitutable for their base types. Essentially, get your inheritance right. In the classic example, type square should not inherit from type rectangle, as they have different properties (you can independently set the sides of a rectangle). Instead, both should inherit from type shape. Interface Segregation Principle – Clients should not be forced to depend upon methods they do not use. Don’t have fat interfaces, rather split them up into smaller, behaviour centric interfaces. Dependency Inversion Principle – There are two parts to this principle: High-level modules should not depend on low-level modules. Both should depend on abstractions. Abstractions should not depend on details. Details should depend on abstractions. In modern development, this is often handled by an IoC (Inversion of Control) container.

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• consume a .net webservice using jQuery

  - by Babunareshnarra

  Implementation shows the way to consume web service using jQuery. The client side AJAX with HTTP POST request is significant when it comes to loading speed and responsiveness.Following is the service created that return's string in JSON.[WebMethod][ScriptMethod(ResponseFormat = ResponseFormat.Json)]public string getData(string marks){    DataTable dt = retrieveDataTable("table", @"              SELECT * FROM TABLE WHERE MARKS='"+ marks.ToString() +"' ");    List<object> RowList = new List<object>();    foreach (DataRow dr in dt.Rows)    {        Dictionary<object, object> ColList = new Dictionary<object, object>();        foreach (DataColumn dc in dt.Columns)        {            ColList.Add(dc.ColumnName,            (string.Empty == dr[dc].ToString()) ? null : dr[dc]);        }        RowList.Add(ColList);    }    JavaScriptSerializer js = new JavaScriptSerializer();    string JSON = js.Serialize(RowList);    return JSON;}Consuming the webservice $.ajax({    type: "POST",    data: '{ "marks": "' + val + '"}', // This is required if we are using parameters    contentType: "application/json",    dataType: "json",    url: "/dataservice.asmx/getData",    success: function(response) {               RES = JSON.parse(response.d);        var obj = JSON.stringify(RES);     }     error: function (msg) {                    alert('failure');     }});Remember to reference jQuery library on the page.

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• The Dispose Pattern (and FxCop warnings)

  - by Scott Dorman

  [This is actually a response to Bill’s blog post, but since it isn’t possible to leave this as a comment on his blog it’s a post here.] There are many different ways to implement the Dispose pattern correctly. Some are (in my opinion) better than others. In Bill’s blog post he presents a particular pattern, which is an excerpt from his book (Effective C#). The issue centers around the fact that a reader took the code sample presented in the book and ran FxCop (Code Analysis) on it, which generated a warning: “Ensure that base.Dispose() is always called.” The “lesson learned” that Bill presents is that “tools are there to help us, not control us.” While I completely agree with the belief that tools are there to help us, I think it’s important to understand why FxCop is raising this particular warning. The code presented in Bill’s book looks like: // Have its own disposed flag.private bool disposed = false;protected override void Dispose(bool isDisposing){ // Don't dispose more than once. if (disposed) return; if (isDisposing) { // TODO: free managed resources here. } // TODO: free unmanaged resources here. // Let the base class free its resources. // Base class is responsible for calling // GC.SuppressFinalize( ) base.Dispose(isDisposing); // Set derived class disposed flag: disposed = true;} This code does follow all of the guidelines for implementing the Dispose pattern. In this case, it’s presumably part of a larger example showing how to implement the pattern as part of a base class. The reason FxCop is warning you about this code is the first if statement in the Dispose method, which will cause the method to exit if disposed is true. The problem here is that there is the possibility that if the disposed flag is true, the call to base.Dispose() will never be executed. As Bill points out, it is possible for some other code elsewhere in the class to set this flag. He states that this is an “unlikely occurrence.” While that is probably true, it can be a potentially dangerous assumption to make and is one that can be easily corrected. By changing the code slightly you can remove this assumption and correct the FxCop violation. private bool disposed = false;protected override void Dispose(bool disposing){ if (!disposed) { if (disposing) { // Dispose managed resources. } // Dispose unmanaged resources. disposed = true; } base.Dispose(disposing);} Using this implementation allows the call to base.Dispose() to always occur, which ensures that the the disposal chain is always properly followed. Technorati Tags: .NET,C#,Dispose Pattern

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• No sound after clean install 11.10

  - by Jorge

  First of all, sorry to ask this, I'm sure that this was asked so many times before. Second, sorry for the English, it's not my native language. And Third, thank you in advance. So, I hope the follow info will help, here's a log. http://www.alsa-project.org/db/?f=07089caf530494bc4bc23e1d1cd56b3a5fae03c6 I already check 'System - Preferences - Sound'. Here's a screenshot http://i.imgur.com/Ghwnj.png > jorge@jorge-desktop:~$ sudo lshw -class multimedia > *-multimedia > description: Multimedia audio controller > product: VT8233/A/8235/8237 AC97 Audio Controller > vendor: VIA Technologies, Inc. > physical id: 11.5 > bus info: pci@0000:00:11.5 > version: 60 > width: 32 bits > clock: 33MHz > capabilities: pm cap_list > configuration: driver=VIA 82xx Audio latency=0 > resources: irq:22 ioport:e400(size=256) Tried with no results: > sudo apt-get remove --purge alsa-base > sudo apt-get remove --purge pulseaudio > sudo apt-get clean && sudo apt-get autoremove > sudo apt-get install alsa-base > sudo apt-get install pulseaudio > sudo apt-get install ubuntu-desktop Also > sudo gedit /etc/default/grub > > from: > > GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" > > to: > > GRUB_CMDLINE_LINUX_DEFAULT="quiet splash radeon.audio=1" > > sudo update-grub > > And Reboot... without any result. EDIT: I made sure that everything it's fine with aplay -l and lspci -v and lsmod; and checked alsamixer, it's not in mute. Well I'm running out of ideas. Thanks.

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• Simple method for reliably detecting code in text?

  - by Jeff Atwood

  GMail has this feature where it will warn you if you try to send an email that it thinks might have an attachment. Because GMail detected the string see the attached in the email, but no actual attachment, it warns me with an OK / Cancel dialog when I click the Send button. We have a related problem on Stack Overflow. That is, when a user enters a post like this one: my problem is I need to change the database but I don't won't to create a new connection. example: DataSet dsMasterInfo = new DataSet(); Database db = DatabaseFactory.CreateDatabase("ConnectionString"); DbCommand dbCommand = db.GetStoredProcCommand("uspGetMasterName"); This user did not format their code as code! That is, they didn't indent by 4 spaces per Markdown, or use the code button (or the keyboard shortcut ctrl+k) which does that for them. Thus, our system is accreting a lot of edits where people have to go in and manually format code for people that are somehow unable to figure this out. This leads to a lot of bellyaching. We've improved the editor help several times, but short of driving over to the user's house and pressing the correct buttons on their keyboard for them, we're at a loss to see what to do next. That's why we are considering a Google GMail style warning: Did you mean to post code? You wrote stuff that we think looks like code, but you didn't format it as code by indenting 4 spaces, using the toolbar code button or the ctrl+k code formatting command. However, presenting this warning requires us to detect the presence of what we think is unformatted code in a question. What is a simple, semi-reliable way of doing this? Per Markdown, code is always indented by 4 spaces or within backticks, so anything correctly formatted can be discarded from the check immediately. This is only a warning and it will only apply to low-reputation users asking their first questions (or providing their first answers), so some false positives are OK, so long as they are about 5% or less. Questions on Stack Overflow can be in any language, though we can realistically limit our check to, say, the "big ten" languages. Per the tags page that would be C#, Java, PHP, JavaScript, Objective-C, C, C++, Python, Ruby. Use the Stack Overflow creative commons data dump to audit your potential solution (or just pick a few questions in the top 10 tags on Stack Overflow) and see how it does. Pseudocode is fine, but we use c# if you want to be extra friendly. The simpler the better (so long as it works). KISS! If your solution requires us to attempt to compile posts in 10 different compilers, or an army of people to manually train a bayesian inference engine, that's ... not exactly what we had in mind.

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• Move Data into the grid for scalable, predictable response times

  - by JuergenKress

  CloudTran is pleased to introduce the availability of the CloudTran Transaction and Persistence Manager for creating scalable, reliable data services on the Oracle Coherence In-Memory Data Grid (IMDG). Use of IMDG architectures has been key to handling today’s web-scale loads because it eliminates database latency by storing important and frequently access data in memory instead of on disk. The CloudTran product lets developers easily use an IMDG for full ACID-compliant transactions without having to be concerned about the location or spread of data. The system has its own implementation of fast, scalable distributed transactions that does NOT depend on XA protocols but still guarantees all ACID properties. Plus, CloudTran asynchronously replicates data going into the IMDG to back-end datastores and back-up data centers, again ensuring ACID properties. CloudTran can be accessed through Java Persistence API (JPA via TopLink Grid) and now, through a new Low-Level API, or LLAPI. This is ideal for use in SOA applications that need data reliability, high availability, performance, and scalability. It is still in its limited beta release, the LLAPI gives developers the ability to use standard put/remove logic available in Coherence and then wrap logic with simple Spring annotations or XML+AspectJ to start transactions. An important feature of LLAPI is the ability to join transactions. This is a common outcome for SOA applications that need to reduce network traffic by aggregating data into single cache entries and then doing SOA service processing in the node holding the data. This results in the need to orchestrate transaction processing across multiple service calls. CloudTran has the capability to handle these “multi-client” transactions at speed with no loss in ACID properties. Developing software around an IMDG like Oracle Coherence is an important choice for today’s web-scale applications and services. But this introduces new architectural considerations to maintain scalability in light of increased network loads and data movement. Without using CloudTran, developers are faced with an incredibly difficult task to ensure data reliability, availability, performance, and scalability when working with an IMDG. Working with highly distributed data that is entirely volatile while stored in memory presents numerous edge cases where failures can result in data loss. The CloudTran product takes care of all of this, leaving developers with the confidence and peace of mind that all data is processed correctly. For those interested in evaluating the CloudTran product and IMDGs, take a look at this link for more information: http://www.CloudTran.com/downloadAPI.ph , or send your questions to [email protected]. SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit  www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Mix Forum Technorati Tags: CloudTran,data grid,M,SOA Community,Oracle SOA,Oracle BPM,BPM,Community,OPN,Jürgen Kress

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• Should library classes be wrapped before using them in unit testing?

  - by Songo

  I'm doing unit testing and in one of my classes I need to send a mail from one of the methods, so using constructor injection I inject an instance of Zend_Mail class which is in Zend framework. Example: class Logger{ private $mailer; function __construct(Zend_Mail $mail){ $this->mail=$mail; } function toBeTestedFunction(){ //Some code $this->mail->setTo('some value'); $this->mail->setSubject('some value'); $this->mail->setBody('some value'); $this->mail->send(); //Some } } However, Unit testing demands that I test one component at a time, so I need to mock the Zend_Mail class. In addition I'm violating the Dependency Inversion principle as my Logger class now depends on concretion not abstraction. Does that mean that I can never use a library class directly and must always wrap it in a class of my own? Example: interface Mailer{ public function setTo($to); public function setSubject($subject); public function setBody($body); public function send(); } class MyMailer implements Mailer{ private $mailer; function __construct(){ $this->mail=new Zend_Mail; //The class isn't injected this time } function setTo($to){ $this->mailer->setTo($to); } //implement the rest of the interface functions similarly } And now my Logger class can be happy :D class Logger{ private $mailer; function __construct(Mailer $mail){ $this->mail=$mail; } //rest of the code unchanged } Questions: Although I solved the mocking problem by introducing an interface, I have created a totally new class Mailer that now needs to be unit tested although it only wraps Zend_Mail which is already unit tested by the Zend team. Is there a better approach to all this? Zend_Mail's send() function could actually have a Zend_Transport object when called (i.e. public function send($transport = null)). Does this make the idea of a wrapper class more appealing? The code is in PHP, but answers doesn't have to be. This is more of a design issue than a language specific feature

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• What's the best way to create a static utility class in python? Is using metaclasses code smell?

  - by rsimp

  Ok so I need to create a bunch of utility classes in python. Normally I would just use a simple module for this but I need to be able to inherit in order to share common code between them. The common code needs to reference the state of the module using it so simple imports wouldn't work well. I don't like singletons, and classes that use the classmethod decorator do not have proper support for python properties. One pattern I see used a lot is creating an internal python class prefixed with an underscore and creating a single instance which is then explicitly imported or set as the module itself. This is also used by fabric to create a common environment object (fabric.api.env). I've realized another way to accomplish this would be with metaclasses. For example: #util.py class MetaFooBase(type): @property def file_path(cls): raise NotImplementedError def inherited_method(cls): print cls.file_path #foo.py from util import * import env class MetaFoo(MetaFooBase): @property def file_path(cls): return env.base_path + "relative/path" def another_class_method(cls): pass class Foo(object): __metaclass__ = MetaFoo #client.py from foo import Foo file_path = Foo.file_path I like this approach better than the first pattern for a few reasons: First, instantiating Foo would be meaningless as it has no attributes or methods, which insures this class acts like a true single interface utility, unlike the first pattern which relies on the underscore convention to dissuade client code from creating more instances of the internal class. Second, sub-classing MetaFoo in a different module wouldn't be as awkward because I wouldn't be importing a class with an underscore which is inherently going against its private naming convention. Third, this seems to be the closest approximation to a static class that exists in python, as all the meta code applies only to the class and not to its instances. This is shown by the common convention of using cls instead of self in the class methods. As well, the base class inherits from type instead of object which would prevent users from trying to use it as a base for other non-static classes. It's implementation as a static class is also apparent when using it by the naming convention Foo, as opposed to foo, which denotes a static class method is being used. As much as I think this is a good fit, I feel that others might feel its not pythonic because its not a sanctioned use for metaclasses which should be avoided 99% of the time. I also find most python devs tend to shy away from metaclasses which might affect code reuse/maintainability. Is this code considered code smell in the python community? I ask because I'm creating a pypi package, and would like to do everything I can to increase adoption.

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• Enterprise Service Bus (ESB): Important architectural piece to a SOA or is it just vendor hype?

  Is an Enterprise Service Bus (ESB) an important architectural piece to a Service-Oriented Architecture (SOA), or is it just vendor hype in order to sell a particular product such as SOA-in-a-box? According to IBM.com, an ESB is a flexible connectivity infrastructure for integrating applications and services; it offers a flexible and manageable approach to service-oriented architecture implementation. With this being said, it is my personal belief that ESBs are an important architectural piece to any SOA. Additionally, generic design patterns have been created around the integration of web services in to ESB regardless of any vendor. ESB design patterns, according to Philip Hartman, can be classified in to the following categories: Interaction Patterns: Enable service interaction points to send and/or receive messages from the bus Mediation Patterns: Enable the altering of message exchanges Deployment Patterns: Support solution deployment into a federated infrastructure Examples of Interaction Patterns: One-Way Message Synchronous Interaction Asynchronous Interaction Asynchronous Interaction with Timeout Asynchronous Interaction with a Notification Timer One Request, Multiple Responses One Request, One of Two Possible Responses One Request, a Mandatory Response, and an Optional Response Partial Processing Multiple Application Interactions Benefits of the Mediation Pattern: Mediator promotes loose coupling by keeping objects from referring to each other explicitly, and it lets you vary their interaction independently Design an intermediary to decouple many peers Promote the many-to-many relationships between interacting peers to “full object status” Examples of Interaction Patterns: Global ESB: Services share a single namespace and all service providers are visible to every service requester across an entire network Directly Connected ESB: Global service registry that enables independent ESB installations to be visible Brokered ESB: Bridges services that are reluctant to expose requesters or providers to ESBs in other domains Federated ESB: Service consumers and providers connect to the master or to a dependent ESB to access services throughout the network References: Mediator Design Pattern. (2011). Retrieved 2011, from SourceMaking.com: http://sourcemaking.com/design_patterns/mediator Hartman, P. (2006, 24 1). ESB Patterns that "Click". Retrieved 2011, from The Art and Science of Being an IT Architect: http://artsciita.blogspot.com/2006/01/esb-patterns-that-click.html IBM. (2011). WebSphere DataPower XC10 Appliance Version 2.0. Retrieved 2011, from IBM.com: http://publib.boulder.ibm.com/infocenter/wdpxc/v2r0/index.jsp?topic=%2Fcom.ibm.websphere.help.glossary.doc%2Ftopics%2Fglossary.html Oracle. (2005). 12 Interaction Patterns. Retrieved 2011, from Oracle® BPEL Process Manager Developer's Guide: http://docs.oracle.com/cd/B31017_01/integrate.1013/b28981/interact.htm#BABHHEHD

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• Web.NET: A Brief Retrospective

  - by Chris Massey

  It’s been several weeks since I had the pleasure of visiting Milan, and joining 150 enthusiastic web developers for a day of server-side frameworks and JavaScript. Lucky for me, I keep good notes. Overall the day went smoothly, with some solid logistics and very attentiveorganizerss, and an impressively diverse audience drawn by the fact that the event was ambitiously run in English. This was great in that it drew a truly pan-European audience (11 countries were represented on the day, and at least 1 visa had to be procured to get someone there!) It was trouble because, in some cases, it pushed speakers outside their comfort zone. Thankfully, despite a slightly rocky start, every session I attended was very well presented, and the consensus on the day was that the speakers were excellent. While I felt that a lot of the speakers had more that they wanted to cover, the topics were well-chosen, every room constantly had a stack of people in it, and all the sessions were pleasingly focused on code & demos. For all that the language barriers occasionally made networking a little challenging,organizerss Simone & Ugo nailed the logistics. Registration was slick, lunch was plentiful, and session management was great. The very generous Rui was kind enough to showcase a short video about Glimpse in his session, which seemed to go down well (Although the audio in the rooms was a little under-powered). Because I think you might need a mid-week chuckle, here are some out-takes.: And lets not forget the Hackathon. The idea was what having just learned about a stack of interesting technologies, attendees could spend an evening (fuelled by pizza and some good Github beer) hacking something together using them. Unfortunately, after a (great)10-hour day, and in many cases facing international travel in the morning, many of the attendees headed straight for their hotel rooms. This idea could work so beautifully, and I’m excited to see how it pans out in 2013. On top of the slick sessions, getting to finally meet Ugo and Simone in the flesh as a pleasure, as was the serendipitous introduction to the most excellent Rui. They’re all fantastic guys who are passionate about the web, and I’m looking forward to finding opportunities to work with them. Simone & Ugo put on a great event, and I’m excited to see what they do next year.

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• How to use Object Type Converter

  - by arun.x.sridharan(at)oracle.com

  UseCase Description A person form where in user will enter String which has to be converted to Number while persisting. From the User Interface we might be getting a String value which has to be persisted in the database as a number in that scenario we can use converters to map the java object which is of type String to its database value which is a Number. For example , there is a 'Person' table in database which is used to store the user details passed from the User Interface. It has a 'Status' column which is of the value  Number. But from the User Interface String values (Active/InActive) are passed . For persisting the user details we can use Object type converter and provide the mappings for status column corresponding to the String values. Object type converter can be used if you wanted to have a mapping for a field for example when departmentName on the entity was of String value and mapped to dept_name field on the database table which is of the value NUMBER.   Implementation steps Sample EJB API for setting the value of status on Person Entity as a String     public void createPerson(String status,String firstName,String lastName) {                Person person = new Person();                // status will be set as a String value received from the User Interface         person.setStatus(status);                person.setFirstname(firstName);        person.setLastname(lastName);                persistPerson(person);         } In the sample code shown above status is passed as a String, this has to be converted to Number. The String value obtained will be set on Person object and persistPerson API will be called for creating a new person from the values passed from the User Interface.  Steps to configure Object type converter: 1. Navigate to Person Entity from persistence.xml and navigate to status field2. Click on Conversion tab and select Converted check box3. Select Object Type Converter radio button and set the Data Type Class to      java.math.BigDecimal and Object Type Class to java.lang.String4. Specify the conversion values for all the values that can be passed from the user interface  as shown below5. Set the Default Object value

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• Card deck and sparse matrix interview questions

  - by MrDatabase

  I just had a technical phone screen w/ a start-up. Here's the technical questions I was asked ... and my answers. What do think of these answers? Feel free to post better answers :-) Question 1: how would you represent a standard 52 card deck in (basically any language)? How would you shuffle the deck? Answer: use an array containing a "Card" struct or class. Each instance of card has some unique identifier... either it's position in the array or a unique integer member variable in the range [0, 51]. Shuffle the cards by traversing the array once from index zero to index 51. Randomly swap ith card with "another card" (I didn't remember how this shuffle algorithm works exactly). Watch out for using the same probability for each card... that's a gotcha in this algorithm. I mentioned the algorithm is from Programming Pearls. Question 2: how to represent a large sparse matrix? the matrix can be very large... like 1000x1000... but only a relatively small number (~20) of the entries are non-zero. Answer: condense the array into a list of the non-zero entries. for a given entry (i,j) in the array... "map" (i,j) to a single integer k... then use k as a key into a dictionary or hashtable. For the 1000x1000 sparse array map (i,j) to k using something like f(i, j) = i + j * 1001. 1001 is just one plus the maximum of all i and j. I didn't recall exactly how this mapping worked... but the interviewer got the idea (I think). Are these good answers? I'm wondering because after I finished the second question the interviewer said the dreaded "well that's all the questions I have for now." Cheers!

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• Silverlight Cream for December 08, 2010 -- #1005

  - by Dave Campbell

  In this Issue: Peter Kuhn, David Anson, Jesse Liberty, Mike Taulty(-2-, -3-), Kunal Chowdhury, Jeremy Likness, Martin Krüger, Beth Massi(-2-, -3-)/ Above the Fold: Silverlight: "Rebuilding the PDC 2010 Silverlight Application (Part 1)" Mike Taulty WP7: "WP7: Glossy text block custom control" Martin Krüger Lightswitch: "How to Create a Screen with Multiple Search Parameters in LightSwitch" Beth Massi From SilverlightCream.com: Requirements of and pitfalls in Windows Phone 7 serialization Peter Kuhn discusses Data Contract Serializer issuses on WP7 and how to work around them. Managed implementation of CRC32 and MD5 algorithms updated; new release of ComputeFileHashes for Silverlight, WPF, and the command-line! David Anson ties up some loose ends from a prior post on hash functions, and updates his CRC32 and MD5 algorithms. Windows Phone From Scratch #9 – Visual State Jesse Liberty's latest Windows Phone from Scratch tutorial up... and is on the Visual State... he extends a Button and codes up the State Transitions. Rebuilding the PDC 2010 Silverlight Application (Part 1) Mike Taulty has taken the time to rebuild the PDC2010 Silverlight App that folks wanted the source for... and he's taking multiple posts to explain the heck out of it. This first one is mostly infrastructure. Rebuilding the PDC 2010 Silverlight Application (Part 2) In the 2nd post of the series, Mike Taulty is handling the In/Out of Browser business because he eventually is going to be going OOB. Rebuilding the PDC 2010 Silverlight Application (Part 3) Part 3 finds Mike Taulty delving into WCF Data Services and getting some data on the screen. Paginating Records in Silverlight DataGrid using PagedCollectionView Kunal Chowdhury continues with his investigation of the PagedCollectionView with this post on Pagination of your data. Old School Silverlight Effects If you haven't seen Jeremy Likness' 'Old School' Effects page yet, go just for the entertainment... you'll find yourself hanging around for the code :) WP7: Glossy text block custom control Martin Krüger's latest post is a very cool custom control for WP7 that displays Glossy text... it ain't Metro, but it looks pretty nice... some of it almost like etched text. How to Create a Screen with Multiple Search Parameters in LightSwitch Looks like Beth Massi got a few Lightswitch posts in while I wasn't looking. First up is this one on a multiple-parameter search screen. Adding Static Images and Logos to LightSwitch Applications In the 2nd post, Beth Massi shows how to add your own static images and logos to Lightswitch apps... in response to reader questions. Getting the Most out of LightSwitch Summary Properties In her latest post, Beth Massi explains what Summary Properties are in Lightswitch and how to use them to get the best results for your users. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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• Big Data – Buzz Words: What is NewSQL – Day 10 of 21

  - by Pinal Dave

  In yesterday’s blog post we learned the importance of the relational database. In this article we will take a quick look at the what is NewSQL. What is NewSQL? NewSQL stands for new scalable and high performance SQL Database vendors. The products sold by NewSQL vendors are horizontally scalable. NewSQL is not kind of databases but it is about vendors who supports emerging data products with relational database properties (like ACID, Transaction etc.) along with high performance. Products from NewSQL vendors usually follow in memory data for speedy access as well are available immediate scalability. NewSQL term was coined by 451 groups analyst Matthew Aslett in this particular blog post. On the definition of NewSQL, Aslett writes: “NewSQL” is our shorthand for the various new scalable/high performance SQL database vendors. We have previously referred to these products as ‘ScalableSQL‘ to differentiate them from the incumbent relational database products. Since this implies horizontal scalability, which is not necessarily a feature of all the products, we adopted the term ‘NewSQL’ in the new report. And to clarify, like NoSQL, NewSQL is not to be taken too literally: the new thing about the NewSQL vendors is the vendor, not the SQL. In other words - NewSQL incorporates the concepts and principles of Structured Query Language (SQL) and NoSQL languages. It combines reliability of SQL with the speed and performance of NoSQL. Categories of NewSQL There are three major categories of the NewSQL New Architecture – In this framework each node owns a subset of the data and queries are split into smaller query to sent to nodes to process the data. E.g. NuoDB, Clustrix, VoltDB MySQL Engines – Highly Optimized storage engine for SQL with the interface of MySQ Lare the example of such category. E.g. InnoDB, Akiban Transparent Sharding – This system automatically split database across multiple nodes. E.g. Scalearc  Summary In simple words – NewSQL is kind of database following relational database principals and provides scalability like NoSQL. Tomorrow In tomorrow’s blog post we will discuss about the Role of Cloud Computing in Big Data. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• Bay Area Coherence Special Interest Group Next Meeting July 21, 2011

  - by csoto

  Date: Thursday, July 21, 2011 Time: 4:30pm - 8:15pm ET (note that Parking at 475 Sansome Closes at 8:30pm) Where: Oracle Office, 475 Sansome Street, San Francisco, CA Google Map We will be providing snacks and beverages. Register! - Registration is required for building security. Presentation Line Up:? 5:10pm - Batch Processing Using Coherence in Oracle Group Policy Administration - Paul Cleary, Oracle Oracle Insurance Policy Administration (OIPA) is a flexible, rules-based policy administration solution that provides full record keeping for all policy lifecycle transactions. One component of OIPA is Cycle processing, which is the batch processing of pending insurance transactions. This presentation introduces OIPA and Cycle processing, describing the unique challenges of processing a high volume of transactions within strict time windows. It then reviews how OIPA uses Oracle Coherence and the Processing Pattern to meet these challenges, describing implementation specifics that highlight the simplicity and robustness of the Processing Pattern. 6:10pm - Secure, Optimize, and Load Balance Coherence with F5 - Chris Akker, F5 F5 Networks, Inc., the global leader in Application Delivery Networking, helps the world’s largest enterprises and service providers realize the full value of virtualization, cloud computing, and on-demand IT. Recently, F5 and Oracle partnered to deliver a novel solution that integrates Oracle Coherence 3.7 with F5 BIG-IP Local Traffic Manager (LTM). This session will introduce F5 and how you can leverage BIG-IP LTM to secure, optimize, and load balance application traffic generated from Coherence*Extend clients across any number of servers in a cluster and to hardware-accelerate CPU-intensive SSL encryption. 7:10pm - Using Oracle Coherence to Enable Database Partitioning and DC Level Fault Tolerance - Alexei Ragozin, Independent Consultant and Brian Oliver, Oracle Partitioning is a very powerful technique for scaling database centric applications. One tricky part of partitioned architecture is routing of requests to the right database. The routing layer (routing table) should know the right database instance for each attribute which may be used for routing (e.g. account id, login, email, etc): it should be fast, it should fault tolerant and it should scale. All the above makes Oracle Coherence a natural choice for implementing such routing tables in partitioned architectures. This presentation will cover synchronization of the grid with multiple databases, conflict resolution, cross cluster replication and other aspects related to implementing robust partitioned architecture. Additional Info:?? - Download Past Presentations: The presentations from the previous meetings of the BACSIG are available for download here. Click on the presentation titles to download the PDF files. - Join the Coherence online community on our Oracle Coherence Users Group on LinkedIn. - Contact BACSIG with any comments, questions, presentation proposals and content suggestions.

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• How can I solve this SAT edge case?

  - by ssb

  I have an SAT implementation that basically works, and the fact that it works is what's giving me a few headaches. Basically there are some situations where using the SAT doesn't quite give me my intended result. One of these involves movement across multiple collision objects. Or to put it another way, if I have several collision boxes lined up next to each other such as to create something like a wall or a floor, movement along that surface while constantly applying force into that surface sometimes causes hangups, i.e. the player stops moving. This illustration shows what I mean: The 2 boxes on the bottom represent a floor, and the box on top/in the middle represents what my player is doing. There are several squares lined up as world obstacles to create some kind of wall, and if I move to the left across this surface while holding the down key then the issue arises. It only happens at the exact dividing point between two blocks. It only happens when moving to the left. At any rate I think I know why it happens, but I don't know how to solve it. Basically when I update my player movement I consider which directions are pressed, naturally, so if down is pressed I will add the speed to the Y component, and so on. But due to the way my SAT is implemented, when the penetration into the shape is the same from both sides it just goes with the smallest axis that it finds first, and it checks collisions against objects in the order that they were created because it goes through a foreach loop on the list of collidable objects. So this all adds up to the effect of if I'm moving to the left over a series of boxes while holding down, it will resolve me back to the right out of the first box and then up out of the box to the right of it, and this continues as long as the penetration is the same. The odd part is that this doesn't happen every time, which I am going to attribute to some oddity regarding multiplying velocity by the game time and causing some minor discrepancies between the lengths. Ultimately what this boils down to is that it will keep resolving me to the right and up, but this is technically expected behavior. All the solutions I can think of only address the symptoms of this problem and not the actual cause, such as not using many blocks to create walls or shapes, which is an option I'd like to keep open. I could also change which axis my algorithm defaults to, but that would just cause problems when going up/down along the walls. What can I do to fix this?

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• CRM vs VRM

  - by David Dorf

  In a previous post, I discussed the potential power of combining social, interest, and location graphs in order to personalize marketing and shopping experiences for consumers.  Marketing companies have been trying to collect detailed information for that very purpose, a large majority of which comes from tracking people on the internet.  But their approaches stem from the one-way nature of traditional advertising.  With TV, radio, and magazines there is no opportunity to truly connect to customers, which has trained marketing companies to [covertly] collect data and segment customers into easily identifiable groups.  To a large extent, we think of this as CRM. But what if we turned this viewpoint upside-down to accommodate for the two-way nature of social media?  The notion of marketing as conversations was the basis for the Cluetrain, an early attempt at drawing attention to the fact that customers are actually unique humans.  A more practical implementation is Project VRM, which is a reverse CRM of sorts.  Instead of vendors managing their relationships with customers, customers manage their relationships with vendors. Your shopping experience is not really controlled by you; rather, its controlled by the retailer and advertisers.  And unfortunately, they typically don't give you a say in the matter.  Yes, they might tailor the content for "female age 25-35 interested in shoes" but that's not really the essence of you, is it?  A better approach is to the let consumers volunteer information about themselves.  And why wouldn't they if it means a better, more relevant shopping experience?  I'd gladly list out my likes and dislikes in exchange for getting rid of all those annoying cookies on my harddrive. I really like this diagram from Beyond SocialCRM as it captures the differences between CRM and VRM. The closest thing to VRM I can find is Buyosphere, a start-up that allows consumers to track their shopping history across many vendors, then share it appropriately.  Also, Amazon does a pretty good job allowing its customers to edit their profile, which includes everything you've ever purchased from Amazon.  You can mark items as gifts, or explicitly exclude them from their recommendation engine.  This is a win-win for both the consumer and retailer. So here is my plea to retailers: Instead of trying to infer my interests from snapshots of my day, please just ask me.  We'll both have a better experience in the long-run.

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• TomEE Integration in NetBeans Next

  - by Geertjan

  At JavaOne 2013, there was a lot of buzz around the TomEE server, e.g., many Tweets, nice party, and a new TomEE consulting company. For those tracking TomEE developments, it is interesting to note that recently the NetBeans IDE development builds have had added to them... TomEE support. Note: The TomEE support described here is not in NetBeans IDE 7.4, but in development builds for the next release of NetBeans IDE.For example, with NetBeans IDE development builds you're able to: register TomEE as a server in the Services window (TomEE has several distributions, e.g., one can use the "with JAX-RS" one, for example) create a Java EE 6 web project (e.g., Maven based) against this server create JPA entities from database create JAX-RS classes from JPA entities create JSF pages from JPA entities the IDE lets you create a new data source for TomEE and deploy it to the server the IDE figures out the components that are already packaged in TomEE, and the fact that (unlike with regular Tomcat), it does not need to package any components such as JSF implementation, persistence provider, or JAX-RS runtime, so that the resulting WAR file is very small the IDE can also do "deploy on save" with TomEE, so that your development cycle is very fast Adam Bien blogged about how he set up TomEE sometime ago, here. The official support in NetBeans IDE will be much more tightly integrated, simplifying the steps Adam describes. For example, the IDE does step 2 from Adam's blog for you, i.e., it sets up TomEE deployment roles. Moreover, it knows about all the technologies included in TomEE so that it can optimize the packaging; it knows about TomEE's persistence setup; it can work with TomEE data sources, etc. Below you see a Maven-based Java EE 6 PrimeFaces application (all entities and JSF pages generated from a database) deployed to TomEE in NetBeans IDE: And here's the management console for configuring and finetuning TomEE in NetBeans IDE: When I tried out the NetBeans IDE development build and TomEE, to see how everything fits together, I was surprised at how fast TomEE started up. Not sure what they did to it, but seems like a server on steroids. And setting it up in NetBeans IDE was trivial. Add the simple set up of TomEE in NetBeans IDE to the many benefits that the widely praised out of the box NetBeans Maven tools make possible, together with the fact that not one single plugin had to be installed to get everything you see described here up and running... and you have a really powerful combination of dev tools, all for free.

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• Composite-like pattern and SRP violation

  - by jimmy_keen

  Recently I've noticed myself implementing pattern similar to the one described below. Starting with interface: public interface IUserProvider { User GetUser(UserData data); } GetUser method's pure job is to somehow return user (that would be an operation speaking in composite terms). There might be many implementations of IUserProvider, which all do the same thing - return user basing on input data. It doesn't really matter, as they are only leaves in composite terms and that's fairly simple. Now, my leaves are used by one own them all composite class, which at the moment follows this implementation: public interface IUserProviderComposite : IUserProvider { void RegisterProvider(Predicate<UserData> predicate, IUserProvider provider); } public class UserProviderComposite : IUserProviderComposite { public User GetUser(SomeUserData data) ... public void RegisterProvider(Predicate<UserData> predicate, IUserProvider provider) ... } Idea behind UserProviderComposite is simple. You register providers, and this class acts as a reusable entry-point. When calling GetUser, it will use whatever registered provider matches predicate for requested user data (if that helps, it stores key-value map of predicates and providers internally). Now, what confuses me is whether RegisterProvider method (brings to mind composite's add operation) should be a part of that class. It kind of expands its responsibilities from providing user to also managing providers collection. As far as my understanding goes, this violates Single Responsibility Principle... or am I wrong here? I thought about extracting register part into separate entity and inject it to the composite. As long as it looks decent on paper (in terms of SRP), it feels bit awkward because: I would be essentially injecting Dictionary (or other key-value map) ...or silly wrapper around it, doing nothing more than adding entires This won't be following composite anymore (as add won't be part of composite) What exactly is the presented pattern called? Composite felt natural to compare it with, but I realize it's not exactly the one however nothing else rings any bells. Which approach would you take - stick with SRP or stick with "composite"/pattern? Or is the design here flawed and given the problem this can be done in a better way?

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