Software is everywhere. Software drives everything in the modern world, including smart automobiles and smartphones, e-commerce and e-learning, social media, and social effects. However, how is software structured and designed? How can programmers guarantee the effectiveness, scalability, dependability, and maintainability of their systems? How do they handle the variety and complexity of software issues and fixes? Software architectural patterns hold the solution.
Software architectural patterns are reusable frameworks for system design and organization. They give software architects and developers a consistent language and a set of best practices. They also aid in addressing the difficulties and trade-offs that come with software engineering.
In this blog, we will examine ten popular software architectural patterns, along with some instances of their uses, pros, and cons. These patterns can be mixed or altered to meet various needs and scenarios; they are not mutually exclusive. You will be able to make better decisions for your software projects and obtain a deeper grasp of software architecture and design by mastering these patterns.
1. Layered Pattern
It splits a software system into four levels and is one of the most popular software architectural patterns. Presentation, application, domain, and infrastructure are its four layers. Every layer speaks solely to its neighboring layers and has a defined role.
- The presentation layer is responsible for displaying the user interface and handling user input. It can use various technologies, such as HTML, CSS, JavaScript, or native frameworks.
- The application layer is responsible for implementing the business logic and workflows of the system. It can use various technologies such as Java, C#, Python, or Ruby.
- The domain layer is responsible for defining the core concepts and the rules of the system. It can use various technologies, such as object-oriented, functional, or declarative paradigms.
- The infrastructure layer is responsible for providing low-level services and data access to the system. It can use various technologies, such as databases, file systems, web services, or cloud platforms.
The layered approach makes it easier to develop and test individual layers, separate concerns, and reuse components. It does, however, come with certain disadvantages, including tight coupling, performance overhead, and a lack of flexibility.
In a Stack Overflow study, 43.4% of developers said they use the layered pattern, making it the most popular software design. Operating systems, networking protocols, and web applications are a few software systems that make use of the layered architecture.
2. Master-Slave Pattern
One popular software architectural pattern for parallel processing is the master-slave pattern. It is made up of a master component that assigns jobs to several slave components and gathers their output. In addition to managing exceptions, the master component is in charge of organizing the entire execution. The slave components are in charge of doing the duties given to them and sending the outcomes back.
- The master component can use various technologies, such as message queues, load balancers, or schedulers.
- Threads, processes, and machines are some of the technologies that slave components can employ.
The system's scalability, performance, and dependability are made possible via the master-slave pattern. It works well with issues that break down into more manageable subissues that can be resolved on their own. But it also brings with it certain drawbacks, like synchronization problems, communication overhead, and single points of failure. The master-slave design is frequently employed in distributed systems, including big data, cloud computing, and the internet of things, according to a Gartner analysis. Software systems that employ the master-slave pattern include genetic algorithms, map-reduce, and database replication.
3. Client-Server Pattern
One essential software architectural pattern for networked systems is the client-server pattern. It involves a server component that uses a network to give services to several client components. The server component is in charge of managing the system's business logic and data storage. The client components are in charge of managing the system's display and user interface.
- The server component may employ a variety of technologies, including web servers, application servers, or database servers.
- The client components can use various technologies, such as web browsers, desktop applications, or mobile applications.
The client-server pattern allows the clients and the server to evolve independently, as long as the interface contract is maintained. It also enables the modularity, interoperability, and accessibility of the system. However, it also introduces some risks, such as security threats, network dependency, server bottlenecks, and compatibility issues.
4. Broker Pattern
The broker pattern is a sophisticated software design paradigm for distributed systems. It introduces a broker component that facilitates communication between components that do not know each other. The broker component serves as a mediator, locating, registering, and invoking the components. They can be found on different devices or platforms, and the components have the ability to provide or request resources or services.
The broker pattern separates the components, allowing them to be spread over multiple workstations or platforms. It also makes the system more transparent, flexible, heterogeneous, and reusable. However, it does have several drawbacks, including performance overhead, reliability concerns, and complexity.
According to an IDC analysis, the broker pattern is rapidly being employed in modern software systems, including microservices, cloud-native, and serverless architectures. The broker pattern is used in software systems such as enterprise application integration, web services, and distributed object systems.
5. Event-Bus Pattern
The event-bus pattern is a popular software architectural pattern for event-driven systems. It consists of an event bus component that broadcasts events to multiple elements that subscribe to them. The event bus component acts as a channel that connects the components without requiring direct coupling. It is possible for the components to act asynchronously in response to events, either as producers or consumers of those events.
The event-bus pattern enables the loose coupling, scalability, extensibility, and responsiveness of the system. It also facilitates asynchronous and event-driven communication between components. However, it also introduces some difficulties, such as debugging, event ordering, event flooding, and event consistency.
According to an InfoQ survey, the event-bus pattern is frequently used in software systems, particularly in sectors such as IoT, gaming, and social media. The event-bus pattern is used in software systems such as graphical user interfaces, publish-subscribe systems, and reactive systems.
6. Model-View-Controller (MVC) Pattern
The MVC pattern is a classic software architectural pattern for user interface design. It separates a software system into three components: a model, a view, and a controller. The view displays the data for the user. The controller handles the user input and updates the model and the view accordingly.
- The model can make use of a variety of technologies, including files, databases, and objects.
- Different technologies, like HTML, XML, or JSON, can be used by the view.
- The controller is capable of utilizing a number of technologies, including PHP, Ruby, and Java.
The MVC pattern facilitates the modularization and the testability of each component, as well as the user interaction and the data visualization. However, it also introduces some drawbacks, such as complexity, code duplication, and synchronization issues.
7. Pipe-Filter Pattern
The pipe-filter pattern is a simple software architectural pattern for data processing. It organizes a software system into a sequence of filters that process data streams. Each filter performs a specific transformation on the data and passes it to the next filter through a pipe. The pipes act as buffers and connectors between the filters.
- Functions, classes, and modules are examples of the technologies that the filters can use.
- The pipes can use various technologies, such as streams, queues, or sockets.
The pipe-filter pattern allows the parallel execution and reuse of filters, as well as the flexibility to change the order or the number of filters. However, it also introduces some challenges, such as performance overhead, data format compatibility, and error handling.
This pattern is widely used in software systems that deal with large and complex data sets, such as image processing, natural language processing, and machine learning. Speech recognition, text analysis, and data processing are a few software applications that make use of the pipe-filter pattern.
8. Blackboard Pattern
The blackboard pattern is a sophisticated software architectural pattern for artificial intelligence. It consists of a blackboard component that stores the problem data and a set of knowledge sources that operate on the data. The knowledge sources are independent and specialized modules that communicate only with the blackboard. By deciding which knowledge sources to activate, the blackboard helps to coordinate the process of solving problems.
The blackboard pattern enables the modularity, extensibility, adaptability, and concurrency of the system. It is useful for complex and ill-defined problems that require multiple sources of knowledge and expertise. However, it also introduces some difficulties, such as complexity, inefficiency, unpredictability, and lack of control.
It is increasingly used in software systems that involve human-like intelligence, such as computer vision, speech recognition, and natural language understanding. The blackboard pattern is used in software systems such as face detection, voice recognition, and machine translation.
9. Peer-to-Peer Pattern
The peer-to-peer pattern is a novel software architectural pattern for distributed systems. It involves a network of peers that act as both clients and servers. Each peer can request and provide services or resources to other peers without relying on a central authority or coordinator. The peers are autonomous and self-organizing, and they can join or leave the network at any time.
- The peers have access to a variety of technologies, including hashes, protocols, and algorithms.
- The services or resources may be various types of data, such as files, videos, or bitcoins.
The peer-to-peer pattern enables the scalability, performance, fault tolerance, and autonomy of the system. It also enables the distribution and sharing of data and computation, as well as the resilience and scalability of the system. However, it also introduces some risks, such as security threats, network congestion, data inconsistency, and quality of service.
The peer-to-peer pattern is rapidly growing in software systems, especially in domains such as file sharing, blockchain, and distributed computing. Bitcoin, for one, is using the peer-to-peer pattern.
10. Interpreter Pattern
The interpreter pattern is a unique software architecture paradigm for language design. It defines how to express and execute a language's syntax and semantics. An abstract syntax tree represents the language's phrases, and an interpreter explores the tree and performs the relevant actions. An evaluator or a compiler can be the interpreter.
- The abstract syntax tree can use various technologies, such as nodes, tokens, or symbols.
- The interpreter relies on parsers, visitors, or code generators.
Domain-specific languages can be created and interpreted, and they can also be extended and modified, thanks to the interpreter pattern. However, it also introduces some challenges, such as performance overhead, complexity, error handling, and debugging difficulties.
The pattern is widely used in software systems that involve scripting, querying, or markup languages, such as Python, SQL, or HTML.
Final Thoughts
In this blog, we looked at ten typical software architectural patterns, their benefits and drawbacks, and some examples of their use. These are not the only patterns, nor are they mutually exclusive. They can be mixed or adjusted to meet various scenarios and needs. Learning these patterns will help you gain a better grasp of software architecture and design.
However, just learning these patterns isn't enough. You must also put them into action, which requires the assistance of a reliable software partner. This is where Flat Rock Technology comes in.
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