• Architecture

Software development is a pursuit characterized by complexity. This can take many forms, such as accommodating complex requirements, technology, or team dynamics. Elevating the level of abstraction helps you manage this complexity and make measurable progress, despite the inherent difficulty of the task.

Suggestions for several strategies that help abstract away complexity follow.

Leverage patterns

Patterns help you take advantage of proven techniques for solving common problems. You can benefit from the experience of seasoned practitioners and avoid "re-inventing the wheel," as the saying goes. The use of patterns is a crucial aspect of an architecture-centric approach to development, because it helps reduce the novelty and diversity of a solution, thus improves quality.

See Patterns for more information.

Design the architecture with components and services

This strategy helps manage software complexity through partitioning a system into a set of loosely coupled and highly cohesive subsystems. The benefits of this approach include the ability to organize the team around a set of smaller, more manageable objectives, and the ability to substitute parts of the system without disturbing the overall cohesion of the system. Exposing services encourages re-use by making the functionality of the system easier to comprehend. Focusing on services makes it possible to understand what the system does from a technical perspective without necessarily having to understand the details of how the system works.

See Component for more information.

Actively promote reuse

Incorporating existing software into an overall architecture helps reduce cost and improve quality by reusing proven working software, rather than developing from scratch. It also helps reduce the burden of maintenance by eliminating duplication in the software. Although often difficult to manage, a project or enterprise can reap significant benefits from a well-executed re-use strategy.

Model key perspectives

Modeling helps raise the level of abstraction because you simplify complex ideas and represent them visually, as illustrations. Good models can convey information that helps the team visualize, specify, construct, and document software. The Unified Modeling Language (UML) provides an industry-standard approach to software modeling.

When applying this strategy, you can use various techniques:.

• Identify the key perspectives: Focus on modeling the things that count. Few (if any) projects benefit from modeling the entire design to a great level of detail. Make sure that you understand why you are modeling something and who will benefit.
• Sketch the design: Not all models need to be detailed completely and presented in a software modeling tool. It is often perfectly acceptable (if not desirable) to produce hand-drawn sketches on paper or on a whiteboard when you are exploring and communicating the architecture and design with your team. You can use a digital camera or an electronic whiteboard to capture these diagrams and share them. For many small projects, this is often all you need. See www.agilemodeling.com for more information.
• Agree on a standard notation: In a team environment, it is important that others can understand your diagrams without much explanation. Choosing a standard notation enables others to quickly comprehend your diagrams without ambiguity. The Unified Modeling Language is an example of a widely understood notation.
• Visualize the code: Many software development tools allow you to view the code as models, making it easier to comprehend static and dynamic aspects of a complex code base.
• Document key architectural perspectives: Even if you choose to model very little of your design, it is often advantageous to produce diagrams that communicate the key architectural aspects of the system. Conveying the "big picture" to the rest of the team helps them understand the overall approach and develop cohesive software.
• Use model-driven development: This approach takes formal and complete models and applies a series of defined transformations, which results in the generation of working software. This technique offers a number of benefits, with many success stories reported. (See www.omg.org/mda for more information.)