Architecture Multiple Inheritance, Polymorphism and newer ways of programming

Once and for all I want to clearify this somewhat subjective and argumentative area of programming. Multiple inheritnace In my current working enviornment I have C++ developers and C# developers which come from totaly different worlds and thus have different opinions on programming layout. Now being a C# and Java developer myself I've never come to the state where I actually needed to use Multiple inheritance, but C++ developers around me tend to through out comments like "That would be a per

Architecture Bulk insert efficiency in NoSQL databases

I am developing a service that needs to perform bulk insert of tens of thousands of rows/items/objects at a time, about 20 times per second. (The NoSQL storage can be sharded, so inserts can work in parallel. The sharding strategy, and sharding in general, do not matter for this discussion.) The question is: which NoSQL products in your opinion exhibit the best performance under such circumstances? The answer should include all costs, including serialization and overhead of chatty/laconic pro

Architecture Design of a Decentralized Twitter

Twitter is a popular social networking service where users can write short messages in a one-to-many fashion (you can read more about it at Wikipedia). I've been reading an interesting article by Alex Payne (former API Lead at Twitter), The Very Last Thing I’ll Write About Twitter, where he argues for a decentralized one-to-many communications mechanism... From a programming perspective, how would this service be designed? I imagine it could be similar to email, where anyone can set up a mail s

WCF architecture: using callbacks, events, 2x service-client?

I have my main application installed (ServerApp) on a LAN server (which is behind a firewall, so the server can access the internet but it cannot be accessed from internet directly (No static IP)), and a monitoring application (MonitorApp) on my PC which is outside the LAN and directly connects to internet. ServerApp should send some notification events (basically some statistics) to MonitorApp in a timely manner (every 1-2 seconds). Performance is a critical factor in this app, so I have

Architecture Using Memcache for Centralization of Distributed Cache Against DB

I am new to memcache and wondering if the following thought works or existed with successful cases or just rubbish going into the bin? Spare me and any guidance is highly appreciated. Here goes... Currently there is 1 MySQL DB already using memcache by using it's spare memory to feed the hungry webserver that serves the frontend. Now we are going to introduce a new DB and webserver again and being not to starve a son to feed another, we are looking at alternative ways to do memcache so that in

Architecture Is Zookeeper a fit for this scenario?

Here's my requirement. I have got a bunch of machines in a cluster ( say about 4 - A,B,C,D). A's job is to poll a database for updates (so, A could be looking for new orders in order table). Once, A receives an update, it verifies which one of B,C,D is relatively free (load balances is the right word I guess). It then orders one of B,C,D to start processing the order. A keep tracks of which order is being processed on B/C/D. B,C,D are like slaves - they only receive updates from A and not

Architecture Building a fault-tolerant soft real-time web application with Erlang/OTP

I would like to build a fault-tolerant soft real-time web application for a pizza delivery shop. It should help the pizza shop to accept phone calls from customers, put them as orders into the system (via a CRM web client) and help the dispatchers to assign delivery drivers to the orders. These goals are nothing unusual, but I would like to make the service available 24/7, i.e. to make it fault-tolerant. Moreover, I would like to make it work very fast and to be very responsive. Below is a v

Architecture Where is it better to validate owner of some document?

We have a WCF-service with a method that, for example, cancels an order by given id. This method can be called from the web by any user of our site. Somewhere inside this method we have to check that order with given id belongs to the user that is currently logged in (we read authorization cookies). Where is it better to perform this check? In WCF method we start business process and somewhere inside it we ask a repository to load an order by id. We can have a number of such opened-to-web op

Architecture ARM v5 shared library (ftd2xx) on ARM v7 platform - hard vs soft float issue

I need to run a program that uses ftd2xx on my BeagleBoard xM rev C running Ubuntu 12.04. I am trying to use the ARM library libftd2xx.so provided here. libFTDI is not an option. The difference that I noticed comes from running readelf -hA on libftd2xx.so vs other libraries on the BeagleBoard that work. The arch-specific section gives OS name as "ARM926EF-S" for ftd2xx instead of "7-A" for other libraries and CPU_arch as "v5TEJ" instead of "v7". I'm assuming this means that the library is mean

Any advantages of von Neumann architecture?

I searched the difference between von Neumann and Harvard architecture and came to conclusion, that comparing to Harward architecture von Neumann has no positive sides, only negative such as "bottleneck" and vulnerability. So why most computers use von Neumann architecture today?

Architecture How do you go about making an e-commerce system support multilingual

We have an e-commerce system that is supporting dynamic content coming from multiple sources. The system is written in Java and uses postgreSQL as the DB. I am looking at how we should go about making the system support multiple languages. I know technically how this can be done, but what would the steps be. Which areas would you start making multilinugual? will it be first the content and the supporting user inputs? Does anyone know of any good white papers regarding this subject? Any h

Architecture Implementing per-user storage usage quota in SaaS products

In a SaaS solution, that allows users to maintain their data on the server, if I have to implement various pricing schemes, where each scheme offers different storage quota, say, Basic subscription gets you 2GB storage, whereas Premium gets you 10GB storage - what kind of architecture one has to use? Do I need to maintain against user profile the quota being used? Will this work only if data is maintained in file system? What happens if data is stored in relational or NoSQL database - how one

tips on software architecture for a CMS

I want to know some tips of good approach to write a CMS application/software for a gaming website such as gameloft. This question is not related to coding etc but please give tips for software architecture?

Architecture Creating URLs in Business Layer

Our Web Project has 3 usual layers: Presentation Layer ( PL ) Business Layer ( BLL ) Data access Layer ( DAL ) We should produce some URLs in BLL but URL helpers and URL generation functionalities are located in PL. In our case we want to produce URLs and send them to telegram Bot. but I believe in some other cases also it will be required. How we can generate URLs in BLL in a correct way when URL generation functionality lies in PL?

Architecture When a Service delegates data retrieval to a Data Mapper, which one should return a Model?

I have set up a basic architecture, in which a Service delegates the retrieval of data to a Data Mapper (pseudocode below). ProductService->fetchById(123); class ProductService { public function fetchById(id) { product = ProductMapper->fetch('id', id); // or product = new Product(ProductMapper->fetch('id', id)) ? return product; } } class ProductMapper { public function fetch(bySomething, value) { // fetch stuff from DB. //

Architecture Advantages & Disadvantages of Brokered vs non-brokered Messaging Systems

I'm trying to design a real-time monitoring & control system that's modular, so it can distributed, and expanded/reconfigured for different hardware & networks. I've quickly come to the conclusion I'll need some kind of distributed enterprise messaging system. But there are many options out there, each with advantages and disadvantages, and some of them dictate different architectures. I'm trying to work out whether I need a broker or brokerless system, whether I need the message reliab

Architecture Recovering from failure in orchestrated deployments

In monolithic systems without orchestration, whenever there’s a temporary problem accessing a resource (ex. Connecting to a database), the typical approach is to keep retrying until recovery is achieved. In systems with a microservices architecture, where typically the boot process is light, removing the retry logic from the application and abort the process, letting the orchestrator restart the process, can reduce the application's complexity. If the orchestrator can deal with service dependen

Architecture Issuing Commands to create N of the same type of event

In my event sourcing model, I have an aggregate modeled after a warehouse. For this I have issued such commands like CreateBox and ChangeBoxLocation. With the CreateBox command, I have implemented it such that it has a 1:n relationship with events. That is, a valid CreateBox command will dispatch two events: BoxCreated and BoxLocationChanged, because an added box should be moved to a location. I noticed that the user's of the system actually add boxes to the system in bulk. For example, 300 b

Architecture Multiple applications on web server is consider Microservice or SOA

I'm preparing for an interview which will contain architectural questions. While I was studying, I was thinking about my past experiences. In my previous job, we put most of our applications (about 8~10) on a single tomcat instances, since we didn't have to worry about scaling. All applications were independent from one another, each one had a different schema on the database, so I believe our apps could be consider microservices. But they were on the same web server, so if it goes down, all

Architecture Should we use 'package by feature' structure with DDD?

After doing some research, I got confirmation that folder-by-feature structure is superior to folder-by-layer structure in the majority of cases. To get some arguments we can read, among others, the following articles or even this answer. Package by features, not layers Feature folders vs Tech folders Package by feature, not layer Package by Layer for Spring Projects Is Obsolete However, all the DDD project examples that I found are made with package-by-layer, most of the time following a

Architecture Synchronize writes to DB from dynamically scaled microservices

Background with example: We are building a stream processing application that receives a stream of data, runs algorithms on the data and stores the results in a database. As an example for this question let's use a stream of purchases. Each purchase has the geo-location of the purchase (store location or IP based location). The stream of purchases is coming from a Kafka topic. We now want to process that stream of data and output some statistics. For example, we want to see the average purcha

What is Frontend Architecture?

I know that there are many takes on the subject, some more code-related and some more conceptual. What is the ideal definition? And why?

Architecture Best practices for integrating third-party modules into your app

We have a few projects that involve building an application that is composed of maybe 50% custom functionality, but then pulls in, say, a wiki, a forum, and other components that are "wheels" that have already been invented that we do not wish to re-write from scratch. These third-party applications usually have their own databases, themes, and authentication systems. Getting things to work like a single-sign-on, or a common theme, or tagging/searching across entities in multiple sub-apps are p

Architecture When should you build a web application vs. a thick client?

I would like to hear other people's advice on when one should build a web application versus building a thick client. Over the last few years, I have participated in several discussions about whether an application should be built (or an old application upgraded) with a web browser interface. Usually these were internal systems used within an organization, not mass-market shrink-wrap products, and they were not actually on the public Internet. I do not want to limit the discussion to these ty

Architecture Tools and standards for technical design document

I would like to know what tools and standards are my colleagues using for technical design documents nowadays. In the past when in my company we were only delivering client-server win-apps we had word templates for our design docs. Our templates always started with the Database diagram, then the UI mockups, field mappings, functionality description, etc... With Word and Visio we had enough. But lately we are combining Wikis, UML diagrams, prototyping tools, etc... With no really strong policy f

Architecture Lighter & Faster workflow for robotlegs: might be better or it has too many downsides?

Currently I'm building quite a large app with flex4+robotlegs+as3signals+google app engine based on python. 1) Well the problem is that I'm finding myself redipsatching the same signals from the view to mediator and from mediator to context. 2) The other problem is that I'm executing commands for signals from mediators that just run 1 method on the model. Remember that working with flex 4, the skin might be separed from the business logic. So I have a skin, a component (SkinnableComponent) fo

Architecture How to distribute a file to multiple clients efficiently?

I am building an application which, hopefully, will be installed on many clients (desktop and mobile). Client A may generate a file and publish that he has it. Clients B-Z may decide they want this file. Some assumptions: files are ~2MB. When one client generates a file chances are most other clients will want that file. I guess this is not the case with most P2P apps. I cannot afford an expensive server farm. I am thinking to use the bittorrent protocol. Is it a good approach assuming I

Architecture Resources to build software engineering skills

Apologies if this question is too open-ended for the site, but it just seemed the best place to ask it. I am a self-taught programmer with little maths in his educational background and who has, through the course of a ten-year career moved slowly from front-end web scripting and web development to middle and data-tier software engineering. As a result there are areas of my knowledge and experience that are somewhat lacking. After a recent review with my manager, it was indicated to me that ov

Architecture Updating DataSet - in which layer?

I try to construct 3-tier application. In DAL I get data from database (No-SQL) to DataSets. In BLL I process this data if it is necessary. In PL I show appropriate data. The question is: If data in database are still updating, and I need to have at once newest 'rows', should I update DataSet in BLL with some timer or somewhere else?

Architecture branch if not equal to PC address

Hey got a question regarding Branch instructions. I have a branch if not equal to instruction located at 0x00002000 (PC) and the following: RS(Register 4) = 0 RT(Register 3) = 7 Therefore branch does not equal and should then follow the following equation: if (rs!=rt) goto (PC+offset) The PC is 0x00002000 and the offset is 0000000000001000 What I have done is converted the offset to 32 bits which will just have an extra 16 0's to the left but I have no idea how to add the two and the lectu

Architecture KendoUI vs Telerik Architectural Difference

I am developing an ASP.Net web api application and using kendoUI for client side. I found out this blog post which describes the differences of KendoUI and Telerik, but it does not reflect any architectural difference between these two. Is there are big difference in these two UI frameworks in terms of there architecture which could result to performance differences? I am curious to know the in depth difference and why Telerik team decided to come up with a new solution as KendoUI.

Architecture Communication between main program and sub modules

I am planning to uses the MEF framework in order to be extensible. My program 3 sub modules/dlls as given below Messenger module - to send/receive messages across the network, includes a thread. A shell extension module . A database module. The main module decides how and when to delegates task to the sub modules. Right now i am planning to use and events and callback to communicate back to main module from a sub module. I need to know what is the best, resource efficent way to communicate

Architecture Writing first angular app. How should I architect this?

I'm writing my first angular app after messing around with some basic todo type apps and am curious at what would be the proper way to architect the controllers from a high level. The app will allow the users to dynamically add/remove homes from a plot and each home can have rooms in it and each room within that home can have products in it. Homes, rooms and products can all be added/removed on the fly and rooms from one home can be moved into other homes. My first pass at it has me thinking I

Architecture TFS organization in large companies (TFS 2012)

everyone I want sugestions about that scenario: 50 persons working in a large e-commerce portal. About 35 devs, 10 QAs, 5 managers, or anything like this. Those devs are divided in teams with specific roles, like front-end team, back-end team, and so on... We have daily publishes in the production environment, and these code published include bug-fixes and new features. Each Developer is working in new features or in bug-fixes and this can involve different silos or impact them. Today in TFS

Difference between In-oder and Out-of-order execution in ARM architecture

As per my understanding in ARM processors, following are the features of In-order execution (1) Executes instructions in sequential order (2) Until current instruction is completed, it will not execute next instruction. (3) Have slower execution speed. Out-of order execution is just opposite behaviour of In-order. (1) Executes instructions in non-sequential order (2) Even if current instruction is NOT completed, it will execute next instruction. (This is done only if the next instruction do

Architecture a definition for system-wide logging mechanism?

While going through some software architecture documents, I came a cross the following: Stakeholder: Operations/Testers The Operations Staff and Testers are concerned with two aspects. Firstly, how the system will be deployed. Secondly, both stakeholders are interested in a system-wide logging mechanism, that is configurable to a degree where they may specify different logging levels and even turning logging on and off for a specific part of the system. I found this hard to understand, so m

General query regarding web application architecture, especially front end

Our application (initially accessible via web, later via mobile app and/or desktop apps) has an application server, which serves and internal API that'll be driven by all end points (React for web, iOS/Android for mobile in the future. etc). This application server will be accessible to those endpoints at app.<mydomain>.com - Currently this is implemented via a Django-REST-framework powered backend hosted on heroku. We also have a landing page which will be served by www.<mydomain>.

Architecture How to handle aggregates relationship in Event Sourcing properly?

When having a somehow "complex" domain model, it's unavoidable to have related entities (that's the sense of aggregate root). But how should I reconstitute relationships from events? Searching by other aggregate id in serialized events is obviously not an option. I have an idea to use such DB structure (for example). It has aggregates tables with just id and foreign keys, to simplify retrieving all necessary events from different entities. Doesn't this break the ES principles?

Architecture Updating all Child object associated with parent record in Salesforce

I have a requirement where I need to update all the Child Object associated with parent object. There are multiple option but I am trying to figure out the best option as more than 30 child objects needs to be updated. Trigger(Most probably Will fail with CPU time limit exceed if not now but some where in future.) Batch class and future method is one option apart from process builder. If anyone has worked on similar requirement, your suggestion will surely help.

Architecture How to orginize dependencies implementing CQRS and DDD

I try to implement DDD service with using of CQRS approach. I'm not using event sourcing. So I have 3 layers: Application, Infrastructure, and Domain. Many peoples said that you can bypass domain for queries, and it is okay. For example, imagine it is necessary for me because of performance issues. Following persistence ignorance, I have repository implementation in Infrastructure. As I see in all implementations of DDD and books, Infrastructure should not be dependent on the Application layer.

Architecture Reuse sub-components in UML component diagram

IN SHORT: Currently I perform a lot of white-box modelling in Sparx Enterprise Architect. However, I wonder that EA does not allow me to add a sub-component twice. Is it a UML modelling issue or a tool problem? ILLUSTRATION: In order to explain my topic, let us assume that we are going to model an apartment. The apartment consists of rooms, namely bath and living room. Both kind of rooms comprise a door. The doors are basically equal - same manufacturer, same product. GOAL: The room's doors are

Architecture Blazor WebAssembly Client project dependencies

This one pertains to Blazor WebAssembly (asp.net core hosted). I have an enum type that represents use cases an application supports. It lives inside Domain project since it is domain specific. I want to use the enum from Blazor Client, but that requires referencing the Domain project (which is not recommended I guess?). The only solution I see is to create a similar enum type inside Shared project and map it to the Domain one on Server side. This sounds inconvenient as I may end up with lots of

Architecture How to event source entire datastore with axon?

I'm trying to design architecture based on CQRS principles. One of the requirements is the ability to introduce over time new projections for query subsystem based on existed event log. To do this I need the ability to iterate over all event records stored in data storage. Is it possible with axon?

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