Search Results

Search found 69357 results on 2775 pages for 'data oriented design'.

Page 2/2775 | < Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >

• How should I design a correct OO design in case of a Business-logic wide operation

  - by Mithir

  EDIT: Maybe I should ask the question in a different way. in light of ammoQ's comment, I realize that I've done something like suggested which is kind of a fix and it is fine by me. But I still want to learn for the future, so that if I develop new code for operations similar to this, I can design it correctly from the start. So, if I got the following characteristics: The relevant input is composed from data which is connected to several different business objects All the input data is validated and cross-checked Attempts are made in order to insert the data to the DB All this is just a single operation from Business side prospective, meaning all of the cross checking and validations are just side effects. I can't think of any other way but some sort of Operator/Coordinator kind of Object which activates the entire procedure, but then I fall into a Functional-Decomposition kind of code. so is there a better way in doing this? Original Question In our system we have many complex operations which involve many validations and DB activities. One of the main Business functionality could have been designed better. In short, there were no separation of layers, and the code would only work from the scenario in which it was first designed at, and now there were more scenarios (like requests from an API or from other devices) So I had to redesign. I found myself moving all the DB code to objects which acts like Business to DB objects, and I've put all the business logic in an Operator kind of a class, which I've implemented like this: First, I created an object which will hold all the information needed for the operation let's call it InformationObject. Then I created an OperatorObject which will take the InformationObject as a parameter and act on it. The OperatorObject should activate different objects and validate or check for existence or any scenario in which the business logic is compromised and then make the operation according to the information on the InformationObject. So my question is - Is this kind of implementation correct? PS, this Operator only works on a single Business-wise Operation.

  Read the article

• Objected oriented approach to structure inside structure

  - by RishiD

  This is for C++ but should apply to any OO language. Trying to figure out the correct object oriented apporach to do the following (this is what I do in C). struct Container { enum type; union { TypeA a; TypeB b; }; } The type field determines if it TypeA or TypeB object. I am using this to handle responses coming back from a connection, they get parsed and get put into this structure and then based on the message type the appropriate fields get filled in. e.g. struct Container parseResponse(bufferIn, bufferLength); Is there an OO approach for doing this?

  Read the article

• DDD: service contains two repository

  - by tikhop

  Does it correct way to have two repository inside one service and will it be an application or domain service? Suppose I have a Passenger object that should contains Passport (government id) object. I am getting Passenger from PassengerRepository. PassengerRepository create request to server and obtain data (json) than parse received data and store inside repository. I have confused because I want to store Passport as Entity and put it to PassportRepository but all information about password contains inside json than i received above. I guess that I should create a PassengerService that will be include PassengerRepository and PassportRepository with several methods like removePassport, addPassport, getAllPassenger and etc. UPDATE: So I guess that the better way is represent Passport as VO and store all passports inside Passenger aggregate. However there is another question: Where I should put the methods (methods calls server api) for management passenger's passport. I think the better place is so within Passenger aggregate.

  Read the article

• Is Design Pattern only for Object-Oriented design?

  - by Tim

  I was wondering if all design Patterns are only used in Object-Oriented design? Are there any design patterns used in non Object-Oriented design? Thanks and regards!

  Read the article

• Any enlightenment for understanding Object Oriented Programming? [closed]

  - by ????

  I studied computer science near the end of 1980s, and wasn't taught OOP that formally. With Pascal or C, when I understand the top-down design of functions, and the idea of black box, then everything just seem to make sense, as if there is a "oh I get it!" -- some kind of totally getting it and enlightenment feeling. But with OOP, all I know was the mechanics: the class, instance, method, inheritance, polymorphism, encapsulation. It was like, I knew all the "this is how it is", but never had the feeling of "I totally get it", the enlightened feeling. Would somebody be able to describe it, or point to a chapter in some book or paper which talks about OOP so that the reader can feel: "I totally get it!" on OOP?

  Read the article

• Tips about how to spread Object Oriented practices

  - by Augusto

  I work for a medium company that has around 250 developers. Unfortunately, lots of them are stuck in a procedural way of thinking and some teams constantly deliver big Transactional Script applications, when in fact the application contains rich logic. They also fail to manage the design dependencies, and end up with services which depend on another large number of services (a clean example of Big Ball of Mud). My question is: Can you suggest how to spread this type of knowledge? I know that the surface of the problem is that these applications have a poor architecture and design. Another issue is that there are some developers who are against writing any kind of test. A few things I'm doing to change this (but I'm either failing or the change is too small are) Running presentations about design principles (SOLID, clean code, etc). Workshops about TDD and BDD. Coaching teams (this includes using sonar, findbugs, jdepend and other tools). IDE & Refactoring talks. A few things I'm thinking to do in the future (but I'm concern that they might not be good) Form a team of OO evangelists, who disseminate an OO way of thinking in differet teams (these people would need to change teams every few months). Running design review sessions, to criticise the design and suggest improvements (even if the improvements are not done because of time constraints, I think this might be useful) . Something I found with the teams I coach, is that as soon as I leave them, they revert back to the old practices. I know I don't spend a lot of time with them, usually just one month. So whatever I'm doing, it doesn't stick. I'm sorry this question is spattered with frustration, but the alterative to write this was to hit my head on the wall until I pass out.

  Read the article

• What is a good design model for my new class?

  - by user66662

  I am a beginning programmer who, after trying to manage over 2000 lines of procedural php code, now has discovered the value of OOP. I have read a few books to get me up to speed on the beginning theory, but would like some advice on practical application. So,for example, let's say there are two types of content objects - an ad and a calendar event. what my application does is scan different websites (a predefined list), and, when it finds an ad or an event, it extracts the data and saves it to a database. All of my objects will share a $title and $description. However, the Ad object will have a $price and the Event object will have $startDate. Should I have two separate classes, one for each object? Should I have a 'superclass' with the $title and $description with two other Ad and Event classes with their own properties? The latter is at least the direction I am on now. My second question about this design is how to handle the logic that extracts the data for $title, $description, $price, and $date. For each website in my predefined list, there is a specific regex that returns the desired value for each property. Currently, I have an extremely large switch statement in my constructor which determines what website I am own, sets the regex variables accordingly, and continues on. Not only that, but now I have to repeat the logic to determine what site I am on in the constructor of each class. This doesn't feel right. Should I create another class Algorithms and store the logic there for each site? Should the functions of to handle that logic be in this class? or specific to the classes whos properties they set? I want to take into account in my design two things: 1) I will add different content objects in the future that share $title and $description, but will have their own properties, so, I want to be able to easily grow these as needed. 2) I will add more websites constantly (each with their own algorithms for data extraction) so I would like to plan efficienty managing and working with these now. I thought about extending the Ad or Event class with 'websiteX' class and store its functions there. But, this didn't feel right either as now I have to manage 100s of little website specific class files. Note, I didn't know if this was the correct site or stackoverflow was the better choice. If so, let me know and I'll post there.

  Read the article

• How to present a stable data model in a public API that allows internal data structures to be changed without breaking the public view of the data?

  - by Max Palmer

  I am in the process of developing an application that allows users to write C# scripts. These scripts allow users to call selected methods and to access and manipulate data in a document. This works well, however, in the development version, scripts access the document's (internal) data structures directly. This means that if we were to change the internal data model/structure, there is a good chance that someone's script will no longer compile. We obviously want to prevent this breaking change from happening, but still want to allow the user to write sensible C# code (whilst not restricting how we develop our internal data model as a result). We therefore need to decouple our scripting API and its data structures from our internal methods and data structures. We've a few ideas as to how we might allow the user to access a what is effectively a stable public version of the document's internal data*, but I wanted to throw the question out there to someone who might have some real experience of this problem. NB our internal document's data structure is quite complex and it could be quite difficult to wrap. We know we want to expose as little as possible in our public API, especially as once it's out there, it's out there for good. Can anyone help? How do scripting languages / APIs decouple their public API and data structures from their internal data structures? Is there no real alternative to having to write a complex interaction layer? If we need to do this, what's a good approach or pattern for wrapping complex data structures that include nested objects, including collections? I've looked at the API facade pattern, which looks like it's trying to address these kinds of issues, but are there alternatives? *One idea is to build a data facade that is kept stable across versions of our application. The facade exposes a set of facade data objects that are used in the script code. These maintain backwards compatibility and wrap access to our internal document's data model.

  Read the article

• When modeling a virtual circuit board, what is the best design pattern to check for cycles?

  - by Wallace Brown

  To make it simple assume you have only AND and OR gates. Each has two inputs and one output. The output of two inputs can be used as an input for the next gate For example: A AND B - E C AND D - F E OR F - G Assuming an arbitrary number of gates, we want to check if the circuit ever connects back into itself at an earlier state? For example: E AND F - A This should be illegal since it creates an endless cycle. What design pattern would best be able to check for these cycles?

  Read the article

• would a composite design pattern be useful for group membership?

  - by changokun

  I'm trying to think about the best way to handle group memberships on a website. People sign up and select checkboxes in a list of interests. Every week we send out interest-themed emails to those members that indicated that interest. however i store the information in the database, while i am working with the lists and generating lists of email addresses or manipulating group memberships, the composite design pattern looked interesting. it would be easy to populate the group, then do some aggregating functions that say... generate the list of email addresses based on the interests. but i'm not sure i'm seeing any other advantages. i do need something scalable, and flexible. thoughts?

  Read the article

• Big Data – Learning Basics of Big Data in 21 Days – Bookmark

  - by Pinal Dave

  Earlier this month I had a great time to write Bascis of Big Data series. This series received great response and lots of good comments I have received, I am going to follow up this basics series with further in-depth series in near future. Here is the consolidated blog post where you can find all the 21 days blog posts together. Bookmark this page for future reference. Big Data – Beginning Big Data – Day 1 of 21 Big Data – What is Big Data – 3 Vs of Big Data – Volume, Velocity and Variety – Day 2 of 21 Big Data – Evolution of Big Data – Day 3 of 21 Big Data – Basics of Big Data Architecture – Day 4 of 21 Big Data – Buzz Words: What is NoSQL – Day 5 of 21 Big Data – Buzz Words: What is Hadoop – Day 6 of 21 Big Data – Buzz Words: What is MapReduce – Day 7 of 21 Big Data – Buzz Words: What is HDFS – Day 8 of 21 Big Data – Buzz Words: Importance of Relational Database in Big Data World – Day 9 of 21 Big Data – Buzz Words: What is NewSQL – Day 10 of 21 Big Data – Role of Cloud Computing in Big Data – Day 11 of 21 Big Data – Operational Databases Supporting Big Data – RDBMS and NoSQL – Day 12 of 21 Big Data – Operational Databases Supporting Big Data – Key-Value Pair Databases and Document Databases – Day 13 of 21 Big Data – Operational Databases Supporting Big Data – Columnar, Graph and Spatial Database – Day 14 of 21 Big Data – Data Mining with Hive – What is Hive? – What is HiveQL (HQL)? – Day 15 of 21 Big Data – Interacting with Hadoop – What is PIG? – What is PIG Latin? – Day 16 of 21 Big Data – Interacting with Hadoop – What is Sqoop? – What is Zookeeper? – Day 17 of 21 Big Data – Basics of Big Data Analytics – Day 18 of 21 Big Data – How to become a Data Scientist and Learn Data Science? – Day 19 of 21 Big Data – Various Learning Resources – How to Start with Big Data? – Day 20 of 21 Big Data – Final Wrap and What Next – Day 21 of 21 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

  Read the article

• implementing dynamic query handler on historical data

  - by user2390183

  EDIT : Refined question to focus on the core issue Context: I have historical data about property (house) sales collected from various sources in a centralized/cloud data source (assume info collection is handled by a third party) Planning to develop an application to query and retrieve data from this centralized data source Example Queries: Simple : for given XYZ post code, what is average house price for 3 bed room house? Complex: What is estimated price for an house at "DD,Some Street,XYZ Post Code" (worked out from average values of historic data filtered by various characteristics of the house: house post code, no of bed rooms, total area, and other deeper insights like house building type, year of built, features)? In addition to average price, the application should support other property info ** maximum, or minimum price..etc and trend (graph) on a selected property attribute over a period of time**. Hence, the queries should not enforce the search based on a primary key or few fixed fields In other words, queries can be What is the change in 3 Bed Room house price (irrespective of location) over last 30 days? What kind of properties we can get for X price (irrespective of location or house type) The challenge I have is identifying the domain (BI/ Data Analytical or DB Design or DB Query Interface or DW related or something else) this problem (dynamic query on historic data) belong to, so that I can do further exploration My findings so far I could be wrong on the following, so please correct me if you think so I briefly read about BI/Data Analytics - I think it is heavy weight solution for my problem and has scalability issues. DB Design - As I understand RDBMS works well if you know Data model at design time. I am expecting attributes about property or other entity (user) that am going to bring in, would evolve quickly. hence maintenance would be an issue. As I am going to have multiple users executing query at same time, performance would be a bottleneck Other options like Graph DB (http://www.tinkerpop.com/) seems to be bit complex (they are good. but using those tools meant for generic purpose, make me think like assembly programming to solve my problem ) BigData related solution are to analyse data from multiple unrelated domains So, Any suggestion on the space this problem fit in ? (Especially if you have design/implementation experience of back-end for property listing or similar portals)

  Read the article

• how should I design Objects around this business requirement?

  - by brainydexter

  This is the business requirement: " A Holiday Package (e.g. New York NY Holiday Package) can be offered in different ways based on the Origin city: From New Delhi to NY From Bombay to NY NY itself ( Land package ) (Bold implies default selection) a. and b. User can fly from either New Delhi or Bombay to NY. c. NY is a Land package, where a user can reach NY by himself and is a standalone holidayPackage. " Let's say I have a class that represents HolidayPackage, Destination (aka City). public class HolidayPackage{ Destination holidayCity; ArrayList<BaseHolidayPackageVariant> variants; BaseHolidayPackageVariant defaultVariant; } public abstract class BaseHolidayPackageVariant { private Integer variantId; private HolidayPackage holidayPackage; private String holidayPackageType; } public class LandHolidayPackageVariant extends BaseHolidayPackageVariant{ } public class FlightHolidayPackageVariant extends BaseHolidayPackageVariant{ private Destination originCity; } What data structure/objects should I design to support: options a default within those options Sidenote: A HolidayPackage can also be offered in different ways based on Hotel selections. I'd like to follow a design which I can leverage to support that use case in the future. This is the backend design I have in mind.

  Read the article

• Design patterns and multiple programming language

  - by Eduard Florinescu

  I am referring here to the design patterns found in the GOF book. First how I see it, there are a few peculiarities to design pattern and knowing multiple language knowledge, for example in Java you really need a singleton but in Python you can do without it you write a module, I saw somewhere a wiki trying to write all GOF patterns for JavaScript and the entries where empty, I guess because it might be a daunting task. If there is someone who is using design patterns and is programming in multiple programming languages supporting the OOP paradigm and can give me a hint on how should I approach design patterns that might help me in all languages I use(Java, JavaScript, Python, Ruby): Can I write good application without knowing exactly the GOF design patterns or I might need some of them which might be crucial and if yes which one, are they alternatives to GOF for specific languages, and should a programmer or a team make its own design patterns set?

  Read the article

• Design patterns and multiple programming languages

  - by Eduard Florinescu

  I am referring here to the design patterns found in the GOF book. First, how I see it, there are a few peculiarities to design pattern and knowing multiple languages, for example in Java you really need a singleton but in Python you can do without it you write a module, I saw somewhere a wiki trying to write all GOF patterns for JavaScript and all the entries were empty, I guess because it might be a daunting task to do that adaptation. If there is someone who is using design patterns and is programming multiple languages supporting the OOP paradigm and can give me a hint on how should I approach design patterns. An approach that might help me in all languages I use(Java, JavaScript, Python, Ruby): Can I write good application without knowing exactly the GOF design patterns or I might need just some of them which might be crucial and if yes which one, are there alternatives to GOF for specific languages, and should a programmer or a team make their own design patterns set?

  Read the article

• Recommended reading for (Object Oriented) application design architecture?

  - by e4rthdog

  In life it doesnt matter if you do one thing for 15 years. You will end up waking one day and asking stuff that are equal to "how do i walk?" :) My specific question is that as a new entrant to C# and OOP i am stepping into many little "details" that need to be addressed. Written a lot of code in VB.NET / cobol / simple php e.t.c surely does not help much into the OOP world... So , even after reading entry level books for C# and watching some videos i recently found out about the "factory model design" for applications. I would appreciate if any of you guys recomment some reading on application design architecture for further reading...

  Read the article

• Design: How to model / where to store relational data between classes

  - by Walker

  I'm trying to figure out the best design here, and I can see multiple approaches, but none that seems "right." There are three relevant classes here: Base, TradingPost, and Resource. Each Base has a TradingPost which can offer various Resources depending on the Base's tech level. Where is the right place to store the minimum tech level a base must possess to offer any given resource? A database seems like overkill. Putting it in each subclass of Resource seems wrong--that's not an intrinsic property of the Resource. Do I have a mediating class, and if so, how does it work? It's important that I not be duplicating code; that I have one place where I set the required tech level for a given item. Essentially, where does this data belong? P.S. Feel free to change the title; I struggled to come up with one that fits.

  Read the article

• Is aspect oriented programming a misnomer?

  - by glenviewjeff

  From everything I have learned about "Aspect Oriented Programming" or "Aspect Oriented Software Development," labeling it as a programming paradigm or methodology appears to be inaccurate. From what I can tell it is not a fundamental technique for programming. To nail down what is meant by "paradigm" and "methodology," please refer to the following definitions from the American Heritage Dictionary. Compare how well or poorly "Object-Oriented Programming" applies to each vs. how well AOP fits. Paradigm: A set of assumptions, concepts, values, and practices that constitutes a way of viewing reality for the community that shares them, especially in an intellectual discipline. Methodology: A body of practices, procedures, and rules used by those who work in a discipline or engage in an inquiry; a set of working methods. "Evidence-based medicine" satisfies the definition of paradigm, but "hysterectomy-based medicine" would be a misnomer because the problem space is too narrow. I am getting the impression that AOP may be misnamed because based on the "oriented-programming" suffix, AOP is alleging to be both a paradigm and a methodology in the same way "Object-Oriented Programming" is. Both of these terms (paradigm and methodology) indicate a fundamental technique, where what I understand about aspects is a technology for solving a narrow problem scope, maybe comparable in magnitude to the static variable feature of Java. If it's true that aspects solve a narrow set of problems, and AOP isn't a misnomer, then why shouldn't all programming techniques be given the "oriented-programming" suffix, such as "inheritance-oriented programming," "dependency-oriented programming," or "scope-oriented programming?"

  Read the article

• How to conciliate OOAD and Database Design?

  - by user1620696

  Recently I've studied about object oriented analysis and design and I liked a lot about it. In every place I've read people say that the idea is to start with the minimum set of requirements and go improving along the way, revisiting this each iteration and making it better as we contiuously develop and contact the customer interested in the software. In particular, one course from Lynda.com said a lot of that: we don't want to spend a lot of time planing everything upfront, we just want to have the minimum to get started and then improve this each iteration. Now, I've also seem a course from the same guy about database design, and there he says differently. He says that although when working with object orientation he likes the agile iterative approach, for database design we should really spend a lot of time planing things upfront instead of just going along the way with the minimum. But this confuses me a little. Indeed, the database will persist important data from our domain model and perhaps configurations of the software and so on. Now, if I'm going to continuously revist the analysis and design of the model, it seems the database design should change also. In the same way, if we plan all the database upfront it seems we are also planing all the model upfront, so the two ideas seems to be incompatible. I really like agile iterative approach, but I'm also looking at getting better design for the database also, so when working with agile iterative approach, how should we deal with the database design?

  Read the article

• I don't get object-oriented programming

  - by Joel J. Adamson

  Note: this question is an edited excerpt from a blog posting I wrote a few months ago. After placing a link to the blog in a comment on Programmers.SE someone requested that I post a question here so that they could answer it. This posting is my most popular, as people seem to type "I don't get object-oriented programming" into Google a lot. Feel free to answer here, or in a comment at Wordpress. What is object-oriented programming? No one has given me a satisfactory answer. I feel like you will not get a good definition from someone who goes around saying “object” and “object-oriented” with his nose in the air. Nor will you get a good definition from someone who has done nothing but object-oriented programming. No one who understands both procedural and object-oriented programming has ever given me a consistent idea of what an object-oriented program actually does. Can someone please give me their ideas of the advantages of object-oriented programming?

  Read the article

• I don't get object-oriented programming

  - by Joel J. Adamson

  Note: this question is an edited excerpt from a blog posting I wrote a few months ago. After placing a link to the blog in a comment on Programmers.SE someone requested that I post a question here so that they could answer it. This posting is my most popular, as people seem to type "I don't get object-oriented programming" into Google a lot. Feel free to answer here, or in a comment at Wordpress. What is object-oriented programming? No one has given me a satisfactory answer. I feel like you will not get a good definition from someone who goes around saying “object” and “object-oriented” with his nose in the air. Nor will you get a good definition from someone who has done nothing but object-oriented programming. No one who understands both procedural and object-oriented programming has ever given me a consistent idea of what an object-oriented program actually does. Can someone please give me their ideas of the advantages of object-oriented programming?

  Read the article

• Web workflow solution - how should I approach the design?

  - by Tom Pickles

  We've been tasked with creating a web based workflow tool to track change management. It has a single workflow with multiple synchronous tasks for the most part, but branch out at a point to tasks running in parallel which meet up later on. There will be all sorts of people using the application, and all of them will need to see their outstanding tasks for each change, but only theirs, not others. There will also be a high level group of people who oversee all changes, so need to see everything. They will need to see tasks which have not been done in the specified time, who's responsible etc. The data will be persisted to a SQL database. It'll all be put together using .Net. I've been trying to learn and implement OOP into my designs of late, but I'm wondering if this is moot in this instance as it may be better to have the business logic for this in stored procedures in the DB. I could use POCO's, a front end layer and a data access layer for the web application and just use it as a mechanism for CRUD actions on the DB, then use SP's fired in the DB to apply the business rules. On the other hand, I could use an object oriented design within the web app, but as the data in the app is state-less, is this a bad idea? I could try and model out the whole application into a class structure, implementing interfaces, base classes and all that good stuff. So I would create a change class, which contained a list of task classes/types, which defined each task, and implement an ITask interface etc. Put end-user types into the tasks to identify who should be doing what task. Then apply all the business logic in the respective class methods etc. What approach do you guys think I should be using for this solution?

  Read the article

• software architecture (OO design) refresher course

  - by PeterT

  I am lead developer and team lead in a small RAD team. Deadlines are tight and we have to release often, which we do, and this is what keep the business happy. While we (the development team) are trying to maintain the quality of the code (clean and short methods), I can't help but notice that the overall quality of the OO design&architecture is getting worse over the time - the library we are working on is gradually reducing itself to a "bag of functions". Well, we try to use the design patterns, but since we don't really have much time for a design as such we are mostly using the creational ones. I have read Code Complete / Design Patterns (GOF & enterprise) / Progmatic Programmer / and many books from Effective XXX series. Should I re-read them again as I have read them a long time ago and forgotten quite a lot, or there are other / better OO design / software architeture books been published since then which I should definitely read? Any ideas, recommendations on how can I get the situation under control and start improving the architecture. The way I see it - I will start improving the architectural / design quality of software components I am working on and then will start helping other team members once I find what is working for me.

  Read the article

• Is the design notion of layers contrived?

  - by Bruce

  Hi all I'm reading through Eric Evans' awesome work, Domain-Driven Design. However, I can't help feeling that the 'layers' model is contrived. To expand on that statement, it seems as if it tries to shoe-horn various concepts into a specific, neat model, that of layers talking to each other. It seems to me that the layers model is too simplified to actually capture the way that (good) software works. To expand further: Evans says: "Partition a complex program into layers. Develop a design within each layer that is cohesive and that depends only on the layers below. Follow standard architectural patterns to provide loose coupling to the layers above." Maybe I'm misunderstanding what 'depends' means, but as far as I can see, it can either mean a) Class X (in the UI for example) has a reference to a concrete class Y (in the main application) or b) Class X has a reference to a class Y-ish object providing class Y-ish services (ie a reference held as an interface). If it means (a), then this is clearly a bad thing, since it defeats re-using the UI as a front-end to some other application that provides Y-ish functionality. But if it means (b), then how is the UI any more dependent on the application, than the application is dependent on the UI? Both are decoupled from each other as much as they can be while still talking to each other. Evans' layer model of dependencies going one way seems too neat. First, isn't it more accurate to say that each area of the design provides a module that is pretty much an island to itself, and that ideally all communication is through interfaces, in a contract-driven/responsibility-driven paradigm? (ie, the 'dependency only on lower layers' is contrived). Likewise with the domain layer talking to the database - the domain layer is as decoupled (through DAO etc) from the database as the database is from the domain layer. Neither is dependent on the other, both can be swapped out. Second, the idea of a conceptual straight line (as in from one layer to the next) is artificial - isn't there more a network of intercommunicating but separate modules, including external services, utility services and so on, branching off at different angles? Thanks all - hoping that your responses can clarify my understanding on this..

  Read the article

• Parallel Class/Interface Hierarchy with the Facade Design Pattern?

  - by Mike G

  About a third of my code is wrapped inside a Facade class. Note that this isn't a "God" class, but actually represents a single thing (called a Line). Naturally, it delegates responsibilities to the subsystem behind it. What ends up happening is that two of the subsystem classes (Output and Timeline) have all of their methods duplicated in the Line class, which effectively makes Line both an Output and a Timeline. It seems to make sense to make Output and Timeline interfaces, so that the Line class can implement them both. At the same time, I'm worried about creating parallel class and interface structures. You see, there are different types of lines AudioLine, VideoLine, which all use the same type of Timeline, but different types of Output (AudioOutput and VideoOutput, respectively). So that would mean that I'd have to create an AudioOutputInterface and VideoOutputInterface as well. So not only would I have to have parallel class hierarchy, but there would be a parallel interface hierarchy as well. Is there any solution to this design flaw? Here's an image of the basic structure (minus the Timeline class, though know that each Line has-a Timeline): NOTE: I just realized that the word 'line' in Timeline might make is sound like is does a similar function as the Line class. They don't, just to clarify.

  Read the article

< Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >