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  • Java: design problem with private-final-int-value and empty constructor

    - by HH
    $ javac InitInt.java InitInt.java:7: variable right might not have been initialized InitInt(){} ^ 1 error $ cat InitInt.java import java.util.*; import java.io.*; public class InitInt { private final int right; //DUE to new Klowledge: Design Problem //I think having an empty constructor like this // is an design problem, shall I remove it? What do you think? // When to use an empty constructor? InitInt(){} public static void main(String[] args) { InitInt test = new InitInt(); System.out.println(test.getRight()); } public int getRight(){return right;} } Initialization problem with Constructor InitInt{ // Still the error, "may not be initialized" // How to initialise it? if(snippetBuilder.length()>(charwisePos+25)){ right=charwisePos+25; }else{ right=snippetBuilder.length()-1; } }

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  • Looking for some Feedback on a DB Design

    - by zSysop
    I'm currently working on a ticketing system which allows our users to submit tickets based on their own needs. i.e. if Department "A" is submitting a ticket they can have certain types of problem categories (such as "Supplies" or "Printer") along with details pertaining to the chosen category. I have laid out a partial db design and i was looking for some feedback on it. I've never built a system from the ground up by myself so i'm a little bit nervous. here's my a draft version of my db design Issues Table Id | CreatedBy | CreateDate | Status | Owner | AssignedTo | AssignmentDate | ----------------------------------------------------------------------------- EquipmentIssueDetails Table Id | IssueId | Serial # | Make | Model | .... --------------------------------------------- SupplyIssueDetails Table Id | IssueId | SupplyId | ItemId | QTY | UnitOfMeasurement ------------------------------------------------------------- NetworkIssueDetails Table Id | IssueId | Supervisor | Details | ------------------------------------------------------------- Notes Table Id | IssueId | Note | CreatedBy | CreateDate ------------------------------------------------------------- Thanks in advance

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  • User control attributes at design-time

    - by ciscoheat
    I'm testing a simple User Control in Visual Studio 2008: A Panel named Wrapper with some controls inside. Can Visual Studio handle this at design time? public partial class TestControl : System.Web.UI.UserControl { [Description("Css class of the div around the control.")] [CssClassProperty] public string CssClass { get { return Wrapper.CssClass; } set { Wrapper.CssClass = value; } } } When setting the CssClass property, it doesn't update the css of the Panel at design time. Am I hoping for too much?

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  • Must all AI states be able to react to any event?

    - by Prog
    FSMs implemented with the State design pattern are a common way to design AI agents. I am familiar with the State design pattern and know how to implement it. How is this used in games to design AI agents? Consider a simplified class Monster, representing an AI agent: class Monster { State state; // other fields omitted public void update(){ // called every game-loop cycle state.execute(this); } public void setState(State state){ this.state = state; } // irrelevant stuff omitted } There are several State subclasses implementing execute() differently. So far, classic State pattern. AI agents are subject to environmental effects and other objects communicating with them. For example, an AI agent might tell another AI agent to attack (i.e. agent.attack()). Or a fireball might tell an AI agent to fall down. This means that the agent must have methods such as attack() and fallDown(), or commonly some message receiving mechanism to understand such messages. With an FSM, the current State of the agent should be the one taking care of such method calls - i.e. the agent delegates to the current state upon every event. Is this correct? If correct, how is this done? Are all states obligated by their superclass to implement methods such as attack(), fallDown() etc., so the agent can always delegate to them on almost every event? Or is it done in some other way?

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  • Should I think about switching to another platform as a .Net developer? [closed]

    - by A. Karimi
    I’ve been a developer for about 10 years and I’ve almost worked on Microsoft stack. At the last several years I’ve been introduced to some good practices such as IoC and other primary design patterns. Now I feel so much comfortable using these patterns and concepts and I’m very angry why we didn’t do that earlier! They exist and used by many developers since more than 5 years ago but why I and many of my colleagues began using them a little later. As you may know Java developers are more ahead in these fields (concepts, patterns and …) than .Net developers. Am I right? Now the question is, “Why we (as .NET developers) weren’t ahead so much? Isn’t it because we are using Microsoft stack?”. I know ALT.NET but why we are trying make a closed ecosystem open and finding alternatives for Microsoft Echo Chamber, while there are natively open ecosystems like Java!? I've always liked most of the Microsoft works very much but I’m worried about this issue. I am even ask myself should I move to another platform?

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  • Database design efficiency with 1 to many relationships limited 1 to 3

    - by Joe
    This is in mysql, but its a database design issue. If you have a one to many relationship, like a bank customer to bank-accounts, typically you would have the table that records the bank-account information have a foreign key that keeps track of the relationship between account and customer. Now this follows the 3rd normal form thing and is a widely accepted way of doing it. Now lets say that you are going to limit a user to only having 3 accounts. The current database implementation will support this and nothing would need to change. But another way to do this would have 3 coloms in the account table that have the id of the 3 respective accounts in them. By the way this violates 1st normal form of db design. The question is what would be the advantage and disadvantages of having the user account relationship recored in this way over the traditional?

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  • What is the best design to this class?

    - by HPT
    assume this class: public class Logger { static TextWriter fs = null; public Logger(string path) { fs = File.CreateText(path); } public static void Log(Exception ex) { ///do logging } public static void Log(string text) { ///do logging } } and I have to use this like: Logger log = new Logger(path); and then use Logger.Log() to log what I want. the question is: is this a good design? to instantiate a class and then always call it's static method? any suggestion yield in better design is appreciated.

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  • Resources for dashboard app backend design

    - by Nix
    I am looking for examples of code/data/infrastructure design for a dashboard-style webapp. I am designing an interface for staff and faculty at a university to access departmental resources and be alerted of cyclical processes, events, deadlines, etc. Technologies I am working with: apache tomcat 6 and a mySQL database, JSP (including JSTL), bootstrap 3, and javascript/jquery. I have basic experience most of these technologies building smaller web apps but was hoping someone could direct me towards a book or other resource that discusses how to design the db architecture (and maybe how to template) for a dashboard, esp. for something like a notification systems. Any suggestions?

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  • Design Documents for Python/Django?

    - by british_trader
    After working on a Django project for a while, I now have to do some design documents for it (UML type stuff). However the code doesn't have classes, but instead uses views.py with modules in it... What would be the best way to show the design of my application from the initial __init__.py, to the urls.py where the HTML requests are then filtered to the specific urls.py in each of the packages and then handled by the views.py? i.e. django-app urls.py views.py settings.py manager.py __init__.py django-package urls.py views.py

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  • Inventory Management OOP design

    - by rgamber
    This was an OOP design and implementation interview question, which I came across on glassdoor.com. Design and implement a inventory management system to minimize the number of missed delivery dates while keeping costs to the company low. Of course there is no right answer to this, but I am not sure I understand the question correctly and am wondering what would be a good answer. Is this as simple as creating an undirected graph with nodes as the delivery points, and edges having weights as the cost of the delivery, and then use a single-source-shortest-path algorithm (like Dijkstras, or Bellman-Ford) on the graph? Not sure if this type of question should be asked here,so let me know and I will delete it.

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  • What do I need to know to design a language and write a interpreter for it?

    - by alFReD NSH
    I know this question has been asked and even there are thousands of books and articles about it. But the problem is that there are too many, and I don't know are they good enough, I have to design a language and write a interpreter for it. The base language is javascript (using nodejs) but it's ok if the compiler was written in another language that I can use from node. I had done a research about compiler compilers in JS, there is jison (Bison implementaion in JS), waxeye, peg.js. I decided to give jison a try, due to the popularity and its being used by coffee script, so it should be able to cover my language too. The grammar definition syntax is similar to bison. But when I tried read the bison manual it seemed very hard to understand for me. And I think it's because I don't know a lot of things about what I'm doing. Like I don't what is formal language theory. I am experienced in Javascript (I'm more talented in JS than most average programmers). And also know basic C and C++ (not much experience but can write a working code for basic things). I haven't had any formal education, so I may not be familiar with some software engineering and computer science principles. Though everyday I try to grasp a lot of articles and improve. So I'm asking if you know any good book or article that can help me. Please also write why the resource you're suggesting is good. --update-- The language I'm trying to create, is not really complicated. All it has is expressions (with or without units), comparisons and logical operators. There are no functions, loops, ... The goal is to create a language that non-programmers can easily learn. And to write customized validations and calculations.

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  • Do cross reference database tables have a place in domain driven design?

    - by Mike Cellini
    First some background. Let's say we have a system where a customer is placing an order in a web interface. The items that customer is ordering can priced in various ways. Sometimes including the cost of delivery and sometimes not at all. That pricing effectively depends on a variety of factors including the vendor's own pricing model, that vendor's individual contracts with customers as well as that vendor's contracts with its own suppliers. Let's assume that once a customer places an order for a particular item and chooses a contract if any, the method of delivery can be determined by variables on those contracts. Those delivery methods also live in their own table in the database and have various properties consumed downstream. It makes sense that a cross reference or lookup table would store that information. That table would be loaded into the domain and could then be used to apply the appropriate delivery method while processing the order. Does this make sense in the context of domain driven design? Or is my thinking too relational? Is this logic that should be built into it's own class/method (I mean beyond apply the cross reference table data)?

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  • What are some good tips for a developer trying to design a scalable MySQL database?

    - by CFL_Jeff
    As the question states, I am a developer, not a DBA. I have experience with designing good ER schemas and am fairly knowledgeable about normalization and good schema design. I have also worked with data warehouses that use dimensional modeling with fact tables and dim tables. However, all of the database-driven applications I've developed at previous jobs have been internal applications on the company's intranet, never receiving "real-world traffic". Furthermore, at previous jobs, I have always had a DBA or someone who knew much more than me about these things. At this new job I just started, I've been asked to develop a public-facing application with a MySQL backend and the data stored by this application is expected to grow very rapidly. Oh, and we don't have a DBA. Well, I guess I am the DBA. ;) As far as designing a database to be scalable, I don't even know where to start. Does anyone have any good tips or know of any good educational materials for a developer who has been sort of shoved into a DBA/database designer role and has been tasked with designing a scalable database to support an application like this? Have any other developers been through this sort of thing? What did you do to quickly become good at this role? I've found some good slides on the subject here but it's hard to glean details from slides. Wish I could've attended that guy's talk. I also found a good blog entry called 5 Ways to Boost MySQL Scalability which had some good information, though some of it was over my head. tl;dr I just want to make sure the database doesn't have to be completely redesigned when it scales up, and I'm looking for tips to get it right the first time. The answer I'm looking for is a "list of things every developer should know about making a scalable MySQL database so your application doesn't perform like crap when the data gets huge".

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  • Rendering design. How can I effectively deal with forward, deferred and transparent rendering?

    - by user1423893
    I have many objects in my game world that all derive from one base class. Each object will have different materials and will therefore be required to be drawn using various rendering techniques. I currently use the following order for rendering my objects. Deferred Forward Transparent (order independent) Each object has a rendering flag that denotes which one of the above methods should be used. The list of base objects in the scene are then iterated through and added to separate lists of deferred, forward or transparent objects based on their rendering flag value. The individual lists are then iterated through and drawn using the order above. Each list is cleared at the end of the frame. This methods works fairly well but it requires different draw methods for each material type. For example each object will require the following methods in order to be compatible with the possible flag settings. object.DrawDeferred() object.DrawForward() object.DrawTransparent() It is also hard to see where methods outside of materials, such as rendering shadow maps, would fit using this "flag & method" design. object.DrawShadow() I was hoping that someone may have some suggestions for improving this rendering process, possibly making it more generic and less verbose?

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  • What Makes a Good Design Critic? CHI 2010 Panel Review

    - by jatin.thaker
    Author: Daniel Schwartz, Senior Interaction Designer, Oracle Applications User Experience Oracle Applications UX Chief Evangelist Patanjali Venkatacharya organized and moderated an innovative and stimulating panel discussion titled "What Makes a Good Design Critic? Food Design vs. Product Design Criticism" at CHI 2010, the annual ACM Conference on Human Factors in Computing Systems. The panelists included Janice Rohn, VP of User Experience at Experian; Tami Hardeman, a food stylist; Ed Seiber, a restaurant architect and designer; John Kessler, a food critic and writer at the Atlanta Journal-Constitution; and Larry Powers, Chef de Cuisine at Shaun's restaurant in Atlanta, Georgia. Building off the momentum of his highly acclaimed panel at CHI 2009 on what interaction design can learn from food design (for which I was on the other side as a panelist), Venkatacharya brought together new people with different roles in the restaurant and software interaction design fields. The session was also quite delicious -- but more on that later. Criticism, as it applies to food and product or interaction design, was the tasty topic for this forum and showed that strong parallels exist between food and interaction design criticism. Figure 1. The panelists in discussion: (left to right) Janice Rohn, Ed Seiber, Tami Hardeman, and John Kessler. The panelists had great insights to share from their respective fields, and they enthusiastically discussed as if they were at a casual collegial dinner. John Kessler stated that he prefers to have one professional critic's opinion in general than a large sampling of customers, however, "Web sites like Yelp get users excited by the collective approach. People are attracted to things desired by so many." Janice Rohn added that this collective desire was especially true for users of consumer products. Ed Seiber remarked that while people looked to the popular view for their target tastes and product choices, "professional critics like John [Kessler] still hold a big weight on public opinion." Chef Powers indicated that chefs take in feedback from all sources, adding, "word of mouth is very powerful. We also look heavily at the sales of the dishes to see what's moving; what's selling and thus successful." Hearing this discussion validates our design work at Oracle in that we listen to our users (our diners) and industry feedback (our critics) to ensure an optimal user experience of our products. Rohn considers that restaurateur Danny Meyer's book, Setting the Table: The Transforming Power of Hospitality in Business, which is about creating successful restaurant experiences, has many applicable parallels to user experience design. Meyer actually argues that the customer is not always right, but that "they must always feel heard." Seiber agreed, but noted "customers are not designers," and while designers need to listen to customer feedback, it is the designer's job to synthesize it. Seiber feels it's the critic's job to point out when something is missing or not well-prioritized. In interaction design, our challenges are quite similar, if not parallel. Software tasks are like puzzles that are in search of a solution on how to be best completed. As a food stylist, Tami Hardeman has the demanding and challenging task of presenting food to be as delectable as can be. To present food in its best light requires a lot of creativity and insight into consumer tastes. It's no doubt then that this former fashion stylist came up with the ultimate catch phrase to capture the emotion that clients want to draw from their users: "craveability." The phrase was a hit with the audience and panelists alike. Sometime later in the discussion, Seiber remarked, "designers strive to apply craveability to products, and I do so for restaurants in my case." Craveabilty is also very applicable to interaction design. Creating straightforward and smooth workflows for users of Oracle Applications is a primary goal for my colleagues. We want our users to really enjoy working with our products where it makes them more efficient and better at their jobs. That's our "craveability." Patanjali Venkatacharya asked the panel, "if a design's "craveability" appeals to some cultures but not to others, then what is the impact to the food or product design process?" Rohn stated that "taste is part nature and part nurture" and that the design must take the full context of a product's usage into consideration. Kessler added, "good design is about understanding the context" that the experience necessitates. Seiber remarked how important seat comfort is for diners and how the quality of seating will add so much to the complete dining experience. Sometimes if these non-food factors are not well executed, they can also take away from an otherwise pleasant dining experience. Kessler recounted a time when he was dining at a restaurant that actually had very good food, but the photographs hanging on all the walls did not fit in with the overall décor and created a negative overall dining experience. While the tastiness of the food is critical to a restaurant's success, it is a captivating complete user experience, as in interaction design, which will keep customers coming back and ultimately making the restaurant a hit. Figure 2. Patanjali Venkatacharya enjoyed the Sardinian flatbread salad. As a surprise Chef Powers brought out a signature dish from Shaun's restaurant for all the panelists to sample and critique. The Sardinian flatbread dish showcased Atlanta's taste for fresh and local produce and cheese at its finest as a salad served on a crispy flavorful flat bread. Hardeman said it could be photographed from any angle, a high compliment coming from a food stylist. Seiber really enjoyed the colors that the dish brought together and thought it would be served very well in a casual restaurant on a summer's day. The panel really appreciated the taste and quality of the different components and how the rosemary brought all the flavors together. Seiber remarked that "a lot of effort goes into the appearance of simplicity." Rohn indicated that the same notion holds true with software user interface design. A tremendous amount of work goes into crafting straightforward interfaces, including user research, prototyping, design iterations, and usability studies. Design criticism for food and software interfaces clearly share many similarities. Both areas value expert opinions and user feedback. Both areas understand the importance of great design needing to work well in its context. Last but not least, both food and interaction design criticism value "craveability" and how having users excited about experiencing and enjoying the designs is an important goal. Now if we can just improve the taste of software user interfaces, people may choose to dine on their enterprise applications over a fresh organic salad.

    Read the article

  • What Makes a Good Design Critic? CHI 2010 Panel Review

    - by Applications User Experience
    Author: Daniel Schwartz, Senior Interaction Designer, Oracle Applications User Experience Oracle Applications UX Chief Evangelist Patanjali Venkatacharya organized and moderated an innovative and stimulating panel discussion titled "What Makes a Good Design Critic? Food Design vs. Product Design Criticism" at CHI 2010, the annual ACM Conference on Human Factors in Computing Systems. The panelists included Janice Rohn, VP of User Experience at Experian; Tami Hardeman, a food stylist; Ed Seiber, a restaurant architect and designer; Jonathan Kessler, a food critic and writer at the Atlanta Journal-Constitution; and Larry Powers, Chef de Cuisine at Shaun's restaurant in Atlanta, Georgia. Building off the momentum of his highly acclaimed panel at CHI 2009 on what interaction design can learn from food design (for which I was on the other side as a panelist), Venkatacharya brought together new people with different roles in the restaurant and software interaction design fields. The session was also quite delicious -- but more on that later. Criticism, as it applies to food and product or interaction design, was the tasty topic for this forum and showed that strong parallels exist between food and interaction design criticism. Figure 1. The panelists in discussion: (left to right) Janice Rohn, Ed Seiber, Tami Hardeman, and Jonathan Kessler. The panelists had great insights to share from their respective fields, and they enthusiastically discussed as if they were at a casual collegial dinner. Jonathan Kessler stated that he prefers to have one professional critic's opinion in general than a large sampling of customers, however, "Web sites like Yelp get users excited by the collective approach. People are attracted to things desired by so many." Janice Rohn added that this collective desire was especially true for users of consumer products. Ed Seiber remarked that while people looked to the popular view for their target tastes and product choices, "professional critics like John [Kessler] still hold a big weight on public opinion." Chef Powers indicated that chefs take in feedback from all sources, adding, "word of mouth is very powerful. We also look heavily at the sales of the dishes to see what's moving; what's selling and thus successful." Hearing this discussion validates our design work at Oracle in that we listen to our users (our diners) and industry feedback (our critics) to ensure an optimal user experience of our products. Rohn considers that restaurateur Danny Meyer's book, Setting the Table: The Transforming Power of Hospitality in Business, which is about creating successful restaurant experiences, has many applicable parallels to user experience design. Meyer actually argues that the customer is not always right, but that "they must always feel heard." Seiber agreed, but noted "customers are not designers," and while designers need to listen to customer feedback, it is the designer's job to synthesize it. Seiber feels it's the critic's job to point out when something is missing or not well-prioritized. In interaction design, our challenges are quite similar, if not parallel. Software tasks are like puzzles that are in search of a solution on how to be best completed. As a food stylist, Tami Hardeman has the demanding and challenging task of presenting food to be as delectable as can be. To present food in its best light requires a lot of creativity and insight into consumer tastes. It's no doubt then that this former fashion stylist came up with the ultimate catch phrase to capture the emotion that clients want to draw from their users: "craveability." The phrase was a hit with the audience and panelists alike. Sometime later in the discussion, Seiber remarked, "designers strive to apply craveability to products, and I do so for restaurants in my case." Craveabilty is also very applicable to interaction design. Creating straightforward and smooth workflows for users of Oracle Applications is a primary goal for my colleagues. We want our users to really enjoy working with our products where it makes them more efficient and better at their jobs. That's our "craveability." Patanjali Venkatacharya asked the panel, "if a design's "craveability" appeals to some cultures but not to others, then what is the impact to the food or product design process?" Rohn stated that "taste is part nature and part nurture" and that the design must take the full context of a product's usage into consideration. Kessler added, "good design is about understanding the context" that the experience necessitates. Seiber remarked how important seat comfort is for diners and how the quality of seating will add so much to the complete dining experience. Sometimes if these non-food factors are not well executed, they can also take away from an otherwise pleasant dining experience. Kessler recounted a time when he was dining at a restaurant that actually had very good food, but the photographs hanging on all the walls did not fit in with the overall décor and created a negative overall dining experience. While the tastiness of the food is critical to a restaurant's success, it is a captivating complete user experience, as in interaction design, which will keep customers coming back and ultimately making the restaurant a hit. Figure 2. Patnajali Venkatacharya enjoyed the Sardian flatbread salad. As a surprise Chef Powers brought out a signature dish from Shaun's restaurant for all the panelists to sample and critique. The Sardinian flatbread dish showcased Atlanta's taste for fresh and local produce and cheese at its finest as a salad served on a crispy flavorful flat bread. Hardeman said it could be photographed from any angle, a high compliment coming from a food stylist. Seiber really enjoyed the colors that the dish brought together and thought it would be served very well in a casual restaurant on a summer's day. The panel really appreciated the taste and quality of the different components and how the rosemary brought all the flavors together. Seiber remarked that "a lot of effort goes into the appearance of simplicity." Rohn indicated that the same notion holds true with software user interface design. A tremendous amount of work goes into crafting straightforward interfaces, including user research, prototyping, design iterations, and usability studies. Design criticism for food and software interfaces clearly share many similarities. Both areas value expert opinions and user feedback. Both areas understand the importance of great design needing to work well in its context. Last but not least, both food and interaction design criticism value "craveability" and how having users excited about experiencing and enjoying the designs is an important goal. Now if we can just improve the taste of software user interfaces, people may choose to dine on their enterprise applications over a fresh organic salad.

    Read the article

  • How to do fixed price quote for design sessions?

    - by Shaul
    Normally when I do a system for a customer, I do design sessions on an hourly rate and then come out with a fixed price quotation for the full system development. Now this customer has thrown me a curveball: he doesn't want an hourly rate for design, either - he wants me to quote a fixed price to do all the design, too! Not that he's trying to cheap out, but he doesn't want to be in a situation where the longer design stretches out, the more he has to pay - and I can understand that. For the business layer it was actually not too difficult to work with this, because from his original functional spec I got a good idea of what the core business objects were, and in our design agreement I defined several objects which would be covered by a fixed design price; if any new non-trivial objects were discovered, they would be considered variances, and those would be billed on an hourly rate. So far so good. But when it comes to the UI, things start getting a lot more woolly. How many screens will there be? Don't know yet. What's going to be on each screen? Don't know yet. All we know is that it's a "dashboard" type of system, and there will be a lot of visual reporting involved e.g. gauges, graphs, etc. So maybe make it fixed price per screen design? Not a great definition; he might say that everything is going to be on one screen. Maybe a price per "visual report" design, including ability to slice & dice? Again not so easy - it might be that the entire system is just one report, and all the intelligence is going to go into how to present that segmentation. Anyone have any ideas how to do a fixed price quotation for a UI design like this?

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  • I'm creating my own scalable, rapid prototyping web server. How should I design it?

    - by Mike Willliams
    I'm going to create my own web server that focuses on scalability, rapid prototyping and the use of JavaScript as the server's scripting language, much like node.js. It will use a Model-View-Controller design pattern so a web application can support more concurrent users just by adding hardware -- and not having to redesign the software. Basically, I'm aiming to produce a framework that allows for fast and easy development of cloud applications without the need to write lots of boiler plate code. I've got some questions about this... How hard will it be to put MySQL in the cloud? How could I go about implementing this and make the resulting product free? Will I have to write my own engine or modify an existing one, if I do what should I watch out for? To make this scalable I need to adjust from one server to hundreds of servers this creates the requirement for the servers to be load balancing, how should I do this? If I balance based on the work load per server I would need gateway to handle all the incoming requests. Is it the right idea to have all the servers check into the gateway and update there status. By having the servers run through a gateway if the gateway dies all the incoming requests are ignored. I'm thinking that having all the servers maintain a list of each other, or at least a few I could rebuild the list of servers and establish a new gateway. Is it worth it? Or should I have a backup gateway that could switch out? Should I let the user choose? How should I pick which server handles the database and which handles the page serving? Should I spread the database so that queries are preformed on multiple servers? Which would theoretically improve performance. The servers would need to mirror the database at least once so that if a server goes down the database isn't corrupted. So this brings up writing another question, should I broadcast SQL queries so that all the servers can take a bit of the work load? If I do it that way wouldn't a query clog up the network so that other queries couldn't be preformed? What are my alternatives? Finally, is there a free solution already out there that might need a little modification that suits my needs?

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  • Class Design -- Multiple Calls from One Method or One Call from Multiple Methods?

    - by Andrew
    I've been working on some code recently that interfaces with a CMS we use and it's presented me with a question on class design that I think is applicable in a number of situations. Essentially, what I am doing is extracting information from the CMS and transforming this information into objects that I can use programatically for other purposes. This consists of two steps: Retrieve the data from the CMS (we have a DAL that I use, so this is essentially just specifying what data from the CMS I want--no connection logic or anything like that) Map the parsed data to my own [C#] objects There are basically two ways I can approach this: One call from multiple methods public void MainMethodWhereIDoStuff() { IEnumerable<MyObject> myObjects = GetMyObjects(); // Do other stuff with myObjects } private static IEnumerable<MyObject> GetMyObjects() { IEnumerable<CmsDataItem> cmsDataItems = GetCmsDataItems(); List<MyObject> mappedObjects = new List<MyObject>(); // do stuff to map the CmsDataItems to MyObjects return mappedObjects; } private static IEnumerable<CmsDataItem> GetCmsDataItems() { List<CmsDataItem> cmsDataItems = new List<CmsDataItem>(); // do stuff to get the CmsDataItems I want return cmsDataItems; } Multiple calls from one method public void MainMethodWhereIDoStuff() { IEnumerable<CmsDataItem> cmsDataItems = GetCmsDataItems(); IEnumerable<MyObject> myObjects = GetMyObjects(cmsDataItems); // do stuff with myObjects } private static IEnumerable<MyObject> GetMyObjects(IEnumerable<CmsDataItem> itemsToMap) { // ... } private static IEnumerable<CmsDataItem> GetCmsDataItems() { // ... } I am tempted to say that the latter is better than the former, as GetMyObjects does not depend on GetCmsDataItems, and it is explicit in the calling method the steps that are executed to retrieve the objects (I'm concerned that the first approach is kind of an object-oriented version of spaghetti code). On the other hand, the two helper methods are never going to be used outside of the class, so I'm not sure if it really matters whether one depends on the other. Furthermore, I like the fact that in the first approach the objects can be retrieved from one line-- most likely anyone working with the main method doesn't care how the objects are retrieved, they just need to retrieve the objects, and the "daisy chained" helper methods hide the exact steps needed to retrieve them (in practice, I actually have a few more methods but am still able to retrieve the object collection I want in one line). Is one of these methods right and the other wrong? Or is it simply a matter of preference or context dependent?

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  • How to overcome shortcomings in reporting from EAV database?

    - by David Archer
    The major shortcomings with Entity-Attribute-Value database designs in SQL all seem to be related to being able to query and report on the data efficiently and quickly. Most of the information I read on the subject warn against implementing EAV due to these problems and the commonality of querying/reporting for almost all applications. I am currently designing a system where almost all the fields necessary for data storage are not known at design/compile time and are defined by the end-user of the system. EAV seems like a good fit for this requirement but due to the problems I've read about, I am hesitant in implementing it as there are also some pretty heavy reporting requirements for this system as well. I think I've come up with a way around this but would like to pose the question to the SO community. Given that typical normalized database (OLTP) still isn't always the best option for running reports, a good practice seems to be having a "reporting" database (OLAP) where the data from the normalized database is copied to, indexed extensively, and possibly denormalized for easier querying. Could the same idea be used to work around the shortcomings of an EAV design? The main downside I see are the increased complexity of transferring the data from the EAV database to reporting as you may end up having to alter the tables in the reporting database as new fields are defined in the EAV database. But that is hardly impossible and seems to be an acceptable tradeoff for the increased flexibility given by the EAV design. This downside also exists if I use a non-SQL data store (i.e. CouchDB or similar) for the main data storage since all the standard reporting tools are expecting a SQL backend to query against. Do the issues with EAV systems mostly go away if you have a seperate reporting database for querying? EDIT: Thanks for the comments so far. One of the important things about the system I'm working on it that I'm really only talking about using EAV for one of the entities, not everything in the system. The whole gist of the system is to be able to pull data from multiple disparate sources that are not known ahead of time and crunch the data to come up with some "best known" data about a particular entity. So every "field" I'm dealing with is multi-valued and I'm also required to track history for each. The normalized design for this ends up being 1 table per field which makes querying it kind of painful anyway. Here are the table schemas and sample data I'm looking at (obviously changed from what I'm working on but I think it illustrates the point well): EAV Tables Person ------------------- - Id - Name - ------------------- - 123 - Joe Smith - ------------------- Person_Value ------------------------------------------------------------------- - PersonId - Source - Field - Value - EffectiveDate - ------------------------------------------------------------------- - 123 - CIA - HomeAddress - 123 Cherry Ln - 2010-03-26 - - 123 - DMV - HomeAddress - 561 Stoney Rd - 2010-02-15 - - 123 - FBI - HomeAddress - 676 Lancas Dr - 2010-03-01 - ------------------------------------------------------------------- Reporting Table Person_Denormalized ---------------------------------------------------------------------------------------- - Id - Name - HomeAddress - HomeAddress_Confidence - HomeAddress_EffectiveDate - ---------------------------------------------------------------------------------------- - 123 - Joe Smith - 123 Cherry Ln - 0.713 - 2010-03-26 - ---------------------------------------------------------------------------------------- Normalized Design Person ------------------- - Id - Name - ------------------- - 123 - Joe Smith - ------------------- Person_HomeAddress ------------------------------------------------------ - PersonId - Source - Value - Effective Date - ------------------------------------------------------ - 123 - CIA - 123 Cherry Ln - 2010-03-26 - - 123 - DMV - 561 Stoney Rd - 2010-02-15 - - 123 - FBI - 676 Lancas Dr - 2010-03-01 - ------------------------------------------------------ The "Confidence" field here is generated using logic that cannot be expressed easily (if at all) using SQL so my most common operation besides inserting new values will be pulling ALL data about a person for all fields so I can generate the record for the reporting table. This is actually easier in the EAV model as I can do a single query. In the normalized design, I end up having to do 1 query per field to avoid a massive cartesian product from joining them all together.

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  • Good event calendaring / scheduling design guide?

    - by Neil McF
    Hello, In an application I'm designing, the user has to be able to specify rather complex event scheduling (continuous time-block vs. daily time-blocks, exception date/times, recurrence patterns etc.) Does anyone know of a good design page for such a thing online? For example, I was highly impressed with this page's description of how to do database audit trails, and would love something similar. Thanks.

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  • Help with 2-part question on ASP.NET MVC and Custom Security Design

    - by JustAProgrammer
    I'm using ASP.NET MVC and I am trying to separate a lot of my logic. Eventually, this application will be pretty big. It's basically a SaaS app that I need to allow for different kinds of clients to access. I have a two part question; the first deals with my general design and the second deals with how to utilize in ASP.NET MVC Primarily, there will initially be an ASP.NET MVC "client" front-end and there will be a set of web-services for third parties to interact with (perhaps mobile, etc). I realize I could have the ASP.NET MVC app interact just through the Web Service but I think that is unnecessary overhead. So, I am creating an API that will essentially be a DLL that the Web App and the Web Services will utilize. The API consists of the main set of business logic and Data Transfer Objects, etc. (So, this includes methods like CreateCustomer, EditProduct, etc for example) Also, my permissions requirements are a little complicated. I can't really use a straight Roles system as I need to have some fine-grained permissions (but all permissions are positive rights). So, I don't think I can really use the ASP.NET Roles/Membership system or if I can it seems like I'd be doing more work than rolling my own. I've used Membership before and for this one I think I'd rather roll my own. Both the Web App and Web Services will need to keep security as a concern. So, my design is kind of like this: Each method in the API will need to verify the security of the caller In the Web App, each "page" ("action" in MVC speak) will also check the user's permissions (So, don't present the user with the "Add Customer" button if the user does not have that right but also whenever the API receives AddCustomer(), check the security too) I think the Web Service really needs the checking in the DLL because it may not always be used in some kind of pre-authenticated context (like using Session/Cookies in a Web App); also having the security checks in the API means I don't really HAVE TO check it in other places if I'm on a mobile (say iPhone) and don't want to do all kinds of checking on the client However, in the Web App I think there will be some duplication of work since the Web App checks the user's security before presenting the user with options, which is ok, but I was thinking of a way to avoid this duplication by allowing the Web App to tell the API not check the security; while the Web Service would always want security to be verified Is this a good method? If not, what's better? If so, what's a good way of implementing this. I was thinking of doing this: In the API, I would have two functions for each action: // Here, "Credential" objects are just something I made up public void AddCustomer(string customerName, Credential credential , bool checkSecurity) { if(checkSecurity) { if(Has_Rights_To_Add_Customer(credential)) // made up for clarity { AddCustomer(customerName); } else // throw an exception or somehow present an error } else AddCustomer(customerName); } public void AddCustomer(string customerName) { // actual logic to add the customer into the DB or whatever // Would it be good for this method to verify that the caller is the Web App // through some method? } So, is this a good design or should I do something differently? My next question is that clearly it doesn't seem like I can really use [Authorize ...] for determining if a user has the permissions to do something. In fact, one action might depend on a variety of permissions and the View might hide or show certain options depending on the permission. What's the best way to do this? Should I have some kind of PermissionSet object that the user carries around throughout the Web App in Session or whatever and the MVC Action method would check if that user can use that Action and then the View will have some ViewData or whatever where it checks the various permissions to do Hide/Show?

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  • WinForm Design View Error

    - by Ramiz Uddin
    I'm getting the following error on form design: Hide Call Stack at EnvDTE80.CodeModel2.DotNetNameFromLanguageSpecific(String LanguageName) at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomParser.CodeTypeDeclarationFromCodeClass(CodeClass vsClass) at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomParser.OnNamespacePopulateTypes(Object sender, EventArgs e) at System.CodeDom.CodeNamespace.get_Types() at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomParser.Parse(TextReader codeStream) at Microsoft.VisualStudio.Design.Serialization.CodeDom.MergedCodeDomParser.System.CodeDom.Compiler.ICodeParser.Parse(TextReader stream) at System.CodeDom.Compiler.CodeDomProvider.Parse(TextReader codeStream) at Microsoft.VisualStudio.Shell.Design.Serialization.CodeDom.CodeDomDocDataAdapter.get_CompileUnit() at Microsoft.VisualStudio.Design.Serialization.CodeDom.VSCodeDomDesignerLoader.PerformLoad(IDesignerSerializationManager serializationManager) at System.ComponentModel.Design.Serialization.BasicDesignerLoader.BeginLoad(IDesignerLoaderHost host) Need help!

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