Search Results

Search found 26869 results on 1075 pages for 'library design'.

Page 18/1075 | < Previous Page | 14 15 16 17 18 19 20 21 22 23 24 25 | Next Page >

Design of input files reading when it comes to defaults/transformations

- by Stefano Borini

Suppose you have an application that reads an input file, on a language that does not support the concept of None. The input is read, parsed, and the contents are stored on a structure for later use. Now, in general you want to keep into account transformation of the data from the input, such as adding default values when not specified, or adding full path information to relative path specified in the input. There are two different strategies to achieve this. The first strategy is to perform these transformations at input file reading time. In practice, you put all the intelligence into the input parser, and your application has no logic to deal with unexpected circumstances, such as an unspecified value. You lose the information of what was specified and what wasn't, but you gain in black-boxing the details. Your "running code" needs that information in any case and in a proper form, and is not concerned if it's the default or a user-specified information. The second strategy is to have the file reader a real one-to-one mapper from the file to a memory-stored object, with no intelligent behavior. unspecified values are not filled (which may however be a problem in languages not supporting None) and data is stored verbatim from the file. The intelligence for recovery must now go into the "running code", which must check what was specified in the file, eventually fall back to a default, or modify the input properly before using it. I would like to know your opinion on these two approaches, and in particular which one you found the most frequently implemented.

Read the article
Difference between Factory Method and Abstract Factory design patterns using C#.Net

- by nijhawan.saurabh

First of all I'll just put both these patterns in context and describe their intent as in the GOF book: Factory Method: Define an interface for creating an object, but let subclasses decide which class to instantiate. Factory Method lets a class defer instantiation to subclasses. Abstract Factory: Provide an interface for creating families of related or dependent objects without specifying their concrete classes. Points to note: Abstract factory pattern adds a layer of abstraction to the factory method pattern. The type of factory is not known to the client at compile time, this information is passed to the client at runtime (How it is passed is again dependent on the system, you may store this information in configuration files and the client can read it on execution). While implementing Abstract factory pattern, the factory classes can have multiple factory methods. In Abstract factory, a factory is capable of creating more than one type of product (Simpilar products are grouped together in a factory) Sample implementation of factory method pattern Let's see the class diagram first: ProductFactory.cs // ----------------------------------------------------------------------- // <copyright file="ProductFactory.cs" company=""> // TODO: Update copyright text. // </copyright> // ----------------------------------------------------------------------- namespace FactoryMethod { using System; using System.Collections.Generic; using System.Linq; using System.Text; /// <summary> /// TODO: Update summary. /// </summary> public abstract class ProductFactory { /// <summary> /// </summary> /// <returns> /// </returns> public abstract Product CreateProductInstance(); } } ProductAFactory.cs // ----------------------------------------------------------------------- // <copyright file="ProductAFactory.cs" company=""> // TODO: Update copyright text. // </copyright> // ----------------------------------------------------------------------- namespace FactoryMethod { using System; using System.Collections.Generic; using System.Linq; using System.Text; /// <summary> /// TODO: Update summary. /// </summary> public class ProductAFactory:ProductFactory { public override Product CreateProductInstance() { return new ProductA(); } } } // ----------------------------------------------------------------------- // <copyright file="ProductBFactory.cs" company=""> // TODO: Update copyright text. // </copyright> // ----------------------------------------------------------------------- namespace FactoryMethod { using System; using System.Collections.Generic; using System.Linq; using System.Text; /// <summary> /// TODO: Update summary. /// </summary> public class ProductBFactory:ProductFactory { public override Product CreateProductInstance() { return new ProductB(); } } } // ----------------------------------------------------------------------- // <copyright file="Product.cs" company=""> // TODO: Update copyright text. // </copyright> // ----------------------------------------------------------------------- namespace FactoryMethod { using System; using System.Collections.Generic; using System.Linq; using System.Text; /// <summary> /// TODO: Update summary. /// </summary> public abstract class Product { public abstract string Name { get; set; } } } // ----------------------------------------------------------------------- // <copyright file="ProductA.cs" company=""> // TODO: Update copyright text. // </copyright> // ----------------------------------------------------------------------- namespace FactoryMethod { using System; using System.Collections.Generic; using System.Linq; using System.Text; /// <summary> /// TODO: Update summary. /// </summary> public class ProductA:Product { public ProductA() { Name = "ProductA"; } public override string Name { get; set; } } } // ----------------------------------------------------------------------- // <copyright file="ProductB.cs" company=""> // TODO: Update copyright text. // </copyright> // ----------------------------------------------------------------------- namespace FactoryMethod { using System; using System.Collections.Generic; using System.Linq; using System.Text; /// <summary> /// TODO: Update summary. /// </summary> public class ProductB:Product { public ProductB() { Name = "ProductA"; } public override string Name { get; set; } } } Program.cs using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace FactoryMethod { class Program { static void Main(string[] args) { ProductFactory pf = new ProductAFactory(); Product product = pf.CreateProductInstance(); Console.WriteLine(product.Name); } } } Normal 0 false false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

Read the article
API Design Techniques

- by Dehumanizer

Is it right or more beautiful to name the functions with an prefix, like in Qt? Or using "many" namespaces, but 'normal' names for functions? For example, slOpenFile(); //"sl" means "some lib" vs some_lib::file_functions::openFile(); UPD: I've read somewhere that the first variant(using some prefix) is better, because the API users can perform 'fast' search among the documentation and in the Internet. E.g. by typing the magic prefix search engine starts to advice the exact functions. Is it enough to use the first variant?

Read the article
MMORPG design for time-limited players

- by Philipp

I believe that there is a significant market of players who would enjoy the exploration and interaction aspects of MMORPGs, but simply don't have the time for the endless grinding marathons which are part of the average MMORPG. MMORPGs are all about interaction between players. But when different players have different amounts of time to invest into a game, those with less time to spend will soon lack behind their power-leveling friends and won't be able to interact with them anymore. One way to solve this would be to limit the progress a player can achieve per day, so that it simply doesn't make sense to play more than one or two hours a day. But even the busiest casual players sometimes like to spend a whole sunday afternoon playing a video game. Just stopping them after two hours would be really frustrating. It also creates a pressure to use the daily progress limit every day, because otherwise the player would feel like wasting something. This pressure would be detrimental for casual gamers. What else could be done to level the playing field between those players who play 40+ hours a week and those who can't play more than 10?

Read the article
Design: classes with same implementation but different method names

- by Dror Helper

I have multiple classes that have similar implementation for different named methods: class MyClassX { public int MyClassXIntMethod(){} public string MyClassXStringMethod(){} } class MyClassY { public int MyClassYIntMethod(){} public string MyClassYStringMethod(){} } the methods inside the classes have similar implementation but because the method's names are different (due to 3rd party constraints) i cannot use inheritance. I'm looking for an elegant solution that would be better than implementing the same functionality over and over again.

Read the article
Software design for non object oriented paradigm

- by Dean

I'm currently working on a project where I'm writing the firmware for an electronic system in C, and have been asked to produce documentation on the development/evolution of the software for the embedded devices. Having developed software in the object oriented paradigm I know to use UML to document the software such as class diagrams with objects, however this does not work for documenting the development of my embedded system. So what should I produce to document the development of my firmware?

Read the article
Asynchronous update design/interaction patterns

- by Andy Waite

These days many apps support asynchronous updates. For example, if you're looking at a list of widgets and you delete one of them then rather than wait for the roundtrip to the server, the app can hide the one you deleted, giving immediate feedback. The actual deletion on the server will happen in the background. This can be seen in web apps, desktop apps, iOS apps, etc. But what about when the background operation fails. How should you feed back to the user? Should you restore the UI to the pre-deletion state? What about when multiple background operations fail together? Does this behaviour/pattern have a name? Perhaps something based on the Command pattern?

Read the article
Where to put business logic in MVC design?

- by BriskLabs Pakistan

I have created a simple MVC java application that adds records through data forms to a database. my app collects data, it also validates it and stores it. This is because the data is being sourced online from different users. the data is mostly numeric in nature. now on the numeric data being stored into database (SQL server) , i wish that my app should be able to perform computations... and display it. the user is not interested in how computations are done so they must be encapsulated. the user must only be able to view the simple computed data which for example A column data - B Column data / C column data etc... and just display it to the user... i know how to write stored procedures for same but i want a 3 tier app I want the data, that I put into the database as a record, worked upon by performing calculations on it. However, the original data should remain unaffected, while the new data, post-calculations, must be stored as a new entity record into the database. Where should I write the code for this background calculation? As it is the rules and business logic... in a new java beans files ?

Read the article
How to deal with Character body parts from Design to Cocos2d

- by Edwin Soho

I'm trying to figure out the pattern the game developers use together with game designers: See the picture below with the independent parts: Questions: 1) Should I create different image parts from different body parts or keep frame by frame animaton? (I know both can be used, but I'm trying to figure what is commonly used in the industry) 2) If I'm going to generate different image parts from different body parts (which is I thing is more logical) how would I export that to Cocos2d (Vector or Bitmap)?

Read the article
Facebook Game database design

- by facebook-100000781341887

Hi, I'm currently develop a facebook mafia like PHP game(of course, a light weight version), here is a simplify database(MySQL) of the game id-a <int3> <for index> uid <chr15> <facebook uid> HP <int3> <health point> exp <int3> <experience> money <int3> <money> list_inventory <chr5> <the inventory user hold...some special here, talk next> ... and 20 other fields just like reputation, num of combat... *the number next to the type is the size(byte) of the type For the list_inventory, there have 40 inventorys in my game, (actually, I have 5 these kind of list in my database), and each user can only contain 1 qty of each inventory, therefore, I assign 5 char for this field and each bit of char as 1 item(5 char * 8 bit = 40 slot), and I will do some manipulation by PHP to extract the data from this 5 byte. OK, I was thinking on this, if this game contains 100,000 user, and only 10% are active, therefore, if use my method, for the space use, 5 byte * 100,000 = 500 KB if I use another method, create a table user_hold_inventory, if the user have the inventory, then insert a record into this table, so, for 10,000 active user, I assume they got all item, but for other, I assume they got no item, here is the fields of the new table id-b <int3> <for index> id-a <int3> <id of the user table> inv_no <int1> <inventory that user hold> for the space use, ([id] (3+3) byte + [inv_no] 1 byte ) * [active user] 10,000 * [all inventory] * 40 = 2.8 MB seems method 2 have use more space, but it consume less CPU power. Please comment these 2 method or please correct me if there have another better method rather than what I think. Another question is, my database contain 26 fields, but I counted 5 of them are not change frquently, should I need to separate it on the other table or not? So many words, thanks for reading :)

Read the article
Design patterns for effects between actors and technology

- by changelog

I'm working on my first game, and taking the opportunity to brush up my C++ (I want to make as much of it as portable as I can.) Whilst working on the technology tree and how it affects actors (spaceships, planets, crew, buildings, etc) I can't find a pattern that decouples these entities enough to feel like a clean approach. Just as an idea, here's the type of effects these actors can have on one another (and techs too) An engineer inside a spaceship boosts its shield A hero in a spaceship in a fleet increases morale A technology improves spaceships' travel distance A building in a planet improves its production The best I can come up with is the Observer pattern, and basically manage it more or less manually (when a crew member enters a spaceship, fire the event; when a new building is built in a planet, fire the event, etc etc.) but it seems to be too tightly coupled to me. I would love to get some ideas about how to approach this better.

Read the article
Optimal Database design regarding functionality of letting user share posts by other users

- by codecool

I want to implement functionality which let user share posts by other users similar to what Facebook and Google+ share button and twitter retweet. There are 2 choices: 1) I create duplicate copy of the post and have a column which keeps track of the original post id and makes clear this is a shared post. 2) I have a separate table shared post where I save the post id which is a foreign key to post id in post table. Talking in terms of programming basically I keep pointer to the original post in a separate table and when need to get post posted by user and also shared ones I do a left join on post and shared post table Post(post_id(PK), post_content, posted_by) SharedPost(post_id(FK to Post.post_id), sharing_user, sharedfrom(in case someone shares from non owners profile)) I am in favour of second choice but wanted to know the advice of experts out there? One thing more posts on my webapp will be more on the lines of facebook size not tweet size.

Read the article
Should we consider code language upon design?

- by Codex73

Summary This question aims to conclude if an applications usage will be a consideration when deciding upon development language. What factors if any could be considered upon language writing could be taken into context. Application Type: Web Question Of the following popular languages, when should we use one or the other? What factors if any could be considered upon language writing could be taken into context. Languages PHP Ruby Python My initial thought is that language shouldn't be considered as much as framework. Things to consider on framework are scalability, usage, load, portability, modularity and many more. Things to consider on Code Writing maybe cost, framework stability, community, etc.

Read the article
Android From Local DB (DAO) to Server sync (JSON) - Design issue

- by Taiko

I sync data between my local DB and a Server. I'm looking for the cleanest way to modelise all of this. I have a com.something.db package That contains a Data Helper and couple of DAO classes that represents objects stored in the db (I didn't write that part) com.something.db --public DataHelper --public Employee @DatabaseField e.g. "name" will be an actual column name in the DB -name @DatabaseField -salary etc... (all in all 50 fields) I have a com.something.sync package That contains all the implementation detail on how to send data to the server. It boils down to a ConnectionManager that is fed by different classes that implements a 'Request' interface com.something.sync --public interface ConnectionManager --package ConnectionManagerImpl --public interface Request --package LoginRequest --package GetEmployeesRequest My issue is, at some point in the sync process, I have to JSONise and de-JSONise my data (E.g. the Employee class). But I really don't feel like having the same Employee class be responsible for both his JSONisation and his actual representation inside the local database. It really doesn't feel right, because I carefully decoupled the rest, I am only stuck on this JSON thing. What should I do ? Should I write 3 Employee classes ? EmployeeDB @DatabaseField e.g. "name" will be an actual column name in the DB -name @DatabaseField -salary -etc... 50 fields EmployeeInterface -getName -getSalary -etc... 50 fields EmployeeJSON -JSON_KEY_NAME = "name" The JSON key happens to be the same as the table name, but it isn't requirement -name -JSON_KEY_SALARY = "salary" -salary -etc... 50 fields It feels like a lot of duplicates. Is there a common pattern I can use there ?

Read the article
PyQt design issues

- by Falmarri

I've been working on a my first real project using PyQt lately. I've done just a little bit of work in Qt for C++ but nothing more than just messing around. I've found that the Qt python bindings are essentially just a straight port of C++ classes into python, which makes sense. The issue is that this creates a lot of messy, unpythonic code. For example if you look at QAbstractItemModel, there's a lot of hoops you have to go through that forces you to hide the actual python. I was just wondering if there's any intention of writing a python implementation of Qt that isn't necessarily just a wrapper? Either by Nokia or anyone else? I really like Qt but I would love to be able to write more pythonic code. I hope this is OK to ask here. I'm not trying to start a GUI war or anything.

Read the article
Inventory management system design problem

- by Steve F

What are the conventions for item batch identifiers in inventory management systems? For example: A retail supermarket can order 'Item X' from either 'Supplier A' or 'Supplier B'. When it completes an order for the item from either supplier, it needs to store the record of the receipt. Inventory quantity for the item is increased upon receipt of the order. However it is also required to store some record of the supplier. Thus some sort of batch identifier is required. This batch identifier will uniquely identify the item received and the supplier from whom it is received. A new batch is created each time items are received in stock (for example, after an order). Hence, for purposes of accounting / auditing, information available to identify an item after it was sold comprises of ITEM_CODE, ITEM_NAME, BATCH_CODE. The BATCH_CODE is unique and is associated with DATE_RECEIVED, SUPPLIER_CODE, QTY_RECEIVED. Is this a complete system specification for the above scenario or has anything significant been left out?

Read the article
How Would You Design This Table?

- by sooprise

I have to create a table where each row needs to store 50 number values. Each row will always need to store 50 number values. If this was a smaller number of values, I would just make fields for each of the values, but because there are 50, this approach seems a bit cumbersome (but since it will always be 50 values, maybe this is the correct approach?). Is there a way to store an array of values in a field? This seems like a nice solution, but the concept is almost identical to creating a relational database.

Read the article
How to design brain games [on hold]

- by samesky

I will wonder if anybody has some information about designing games for brain improvement. Recently lumosity is into a gear. I guess they research a lot or have experts. But is there any other research paper that is publicly available for designing the brain games ? Any equation or data that can help? Or what characteristics a brain game should have ? I am getting interested on this and search internet a lot, but unfortunately I could not find the core structure of it. It will really a helpful for me if somebody can give some information. Thank you.

Read the article
design an extendible and pluggable business logic flow handler in php

- by Broncha

I am working on a project where I need to allow a pluggable way to inject business processes in the normal data flow. eg There is an ordering system. The standard flow of the application is A consumer orders an item. Pays for it and card is authorized. Admin captures the payment. Order is marked as complete and item is shipped. But this process may vary (extra steps in between) for different clients. Say a client would need to validate the location of the consumer before he is presented with a credit card form, OR his policies might require some other processes in between. I am thinking of using State Pattern for processing orders, saving the current state of the order in database, and initializing the state of order from the saved state. I would also need some mechanism, where a small plugin would be able to inject business specific states in the state machine. Am I thinking the right way? Are there already implemented patterns for this kind of situation? I am working with Codeigniter and basically this would mean for me, to redirect to proper controller according to the current state of the order. Like, if the state of the order is unconfirmed then redirect the user to details page and then change the state to pending. If some client would need to do some validation, then register an intermediate state between unconfirmed and pending Please suggest.

Read the article
Client-server application design issue

- by user2547823

I have a collection of clients on server's side. And there are some objects that need to work with that collection - adding and removing clients, sending message to them, updating connection settings and so on. They should perform these actions simultaneously, so mutex or another synchronization primitive is required. I want to share one instance of collection between these objects, but all of them require access to private fields of collection. I hope that code sample makes it more clear[C++]: class Collection { std::vector< Client* > clients; Mutex mLock; ... } class ClientNotifier { void sendMessage() { mLock.lock(); // loop over clients and send message to each of them } } class ConnectionSettingsUpdater { void changeSettings( const std::string& name ) { mLock.lock(); // if client with this name is inside collection, change its settings } } As you can see, all these classes require direct access to Collection's private fields. Can you give me an advice about how to implement such behaviour correctly, i.e. keeping Collection's interface simple without it knowing about its users?

Read the article
Proper library for enums

- by Bobson

I'm trying to refactor some code such that the display is separate from the implementation, and I'm not sure where to put the existing enums. My project is currently structured as follows: Utilities RemoteData (Depends on: Utilities) LocalData (Depends on: RemoteData, Utilities) RemoteWeb (Depends on: RemoteData, Utilities) LocalWeb (Depends on: RemoteData, LocalData, Utilities) I'm now trying to add "ViewLibrary (Depends on: Utilities)" to this list, and then adding it as a new dependency to both RemoteWeb and LocalWeb. It will contain a set of interfaces which the other two projects will implement, use to populate the view, and then consume the result. There's an enum which is currently used in all the projects except Utilities. It thus lives in the RemoteData project, because everything else depends on it. But this new ViewLibrary won't depend on either data project. So how will it know about this enum? Some options I see: Create a new project just for shared enum values. Add it to Utilities, even though it is related to data. Define it a second time in ViewLibrary, and require both RemoteWeb and LocalWeb to convert the one type into the other when they access the shared views. Add a dependency on RemoteData to the ViewLibrary, even though it's supposed to be independent of data-source. Are there any better options? Is this structure flawed to begin with?

Read the article
Layering Design Pattern in Java clean code style

- by zeraDev

As a Java developer, I am developing trying to use the clean code rules. But in my team we are facing a concrete problem: We have a business layer offering a service called "createObject", this service makes a lot of operation which can result to problem. E.g: parentObjectDontExist, objectAlreadyExist, dontHaveAuthorizationToCreate, operationFailed... and we want the UI using this service to display different information messages depending which error occurred. In old java dev, we should have create all signed exception type and throw it in createObject. As Clean code says, it is forbidden to use Exception for business logic AND signed exceptions are evil... Why not...But i don't know how to solved this problem and i don't want to use return code. How do you do? Thanks for youre experience return.

Read the article
Android design advice - services & broadcast receivers

- by basudz

I'm in the process of learning the Android SDK and creating some projects to get a grasp on the system. The current project I'm working with works just fine but I'd like to get some advice about other ways I can go about designing it. Here's what it needs to do. When a text message is received from a specific number, it should fire off a toast message that repeats at a certain interval for a specific duration. To make this work, I created an SMS BroadcastReceiver and checked the incoming messages for the number I'm looking for. If found, an IntentService would be started that would pull out the interval and duration from saved shared prefs. The IntentService would then fire off a broadcast. The BroadcastReceiver for this would catch it and use the AlarmManager to handle the toast message repetitions. This all works just fine, but I'm wondering if there's a cleaner or more efficient way of going about doing this? Any suggestions or advice?

Read the article
What OO Design to use ( is there a Design Pattern )?

- by Blundell

I have two objects that represent a 'Bar/Club' ( a place where you drink/socialise). In one scenario I need the bar name, address, distance, slogon In another scenario I need the bar name, address, website url, logo So I've got two objects representing the same thing but with different fields. I like to use immutable objects, so all the fields are set from the constructor. One option is to have two constructors and null the other fields i.e: class Bar { private final String name; private final Distance distance; private final Url url; public Bar(String name, Distance distance){ this.name = name; this.distance = distance; this.url = null; } public Bar(String name, Url url){ this.name = name; this.distance = null; this.url = url; } // getters } I don't like this as you would have to null check when you use the getters In my real example the first scenario has 3 fields and the second scenario has about 10, so it would be a real pain having two constructors, the amount of fields I would have to declare null and then when the object are in use you wouldn't know which Bar you where using and so what fields would be null and what wouldn't. What other options do I have? Two classes called BarPreview and Bar? Some type of inheritance / interface? Something else that is awesome?

Read the article
Advice needed on Process - Service Design

- by user99314

Need some advice from experts on designing a flow. Create a service that will read a csv file which may contain anywhere over 6000+ rows of individual ids as shown in the sample below. Need to read that file and go to oracle database and fetch a vname,vnumber,vid of each id in the csv and then go to document repository i.e. Oracle UCM and download all documents matching vname,vnumber,vid there can be =0 documents for each vname,vnumber,vid and save them on a file system. UCM exposes a webservice to dowload the documents. Finally create a new csv appending the filenames that are downloaded for each id. Need to keep track of any errors but need to make sure to go over the whole ids in the csv to download the documents and skip in case of errors. Need some advice on how to go about designing this as there may be over 6000+ rows in a csv file and looping it and hitting the database for each individual id and then hitting a UCM may be a bit expensive so open for any idea. How to go by designing this solution. Wondering if messaging can be helpful here or offloading process of getting the vname,vnumber,vid to pl/sql packages, creating staging tables etc. Initial csv that contains ids: **ID** 12345a 12s345 3456fr we9795 we9797 Final csv output: **ID Files Downloaded from UCM** 12345a a.pdf,b.doc,d.txt 12s345 a1.pdf,s2.pdf,f4.gif 3456fr b.xls we9795 we9797 x.doc Thanks

Read the article

< Previous Page | 14 15 16 17 18 19 20 21 22 23 24 25 | Next Page >