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In the ever-evolving landscape of software development, agile methodologies have gained significant popularity due to their flexible and collaborative nature. One such approach is Extreme Programming: Despite the funny name it is worth a second look, even more so than the omnipresent Scrum. Just as Scrum, XP is about simplicity, communication, feedback, respect, and courage. But in addition, you will see that XP fills some of Scrum’s gaps when it comes to the practical details of how to write code in an agile project. In this article, we will explore the key principles and practices of XP and how they contribute to the success of software projects.
Core Values of Extreme Programming
In this section we’ll first take a look at the (high-level) values. After that, I’ve summarized my most important learnings about the process so far. If you want to learn more about XP, check out this well written guided tour on XP.
1. Simplicity
XP advocates for doing only what is necessary and requested, avoiding unnecessary complexities. The focus is on creating software that the development team can be proud of and maintain effectively in the long term, without incurring unneccessary costs (which typically increase exponentially with system size).
2. Communication
Effective communication is essential in XP. The development team collaborates closely on all aspects of the project, from requirements engineering to code implementation. By fostering constant communication, XP enables the team to align their efforts and ensure a shared understanding of the project goals.
3. Feedback
XP places great emphasis on receiving and acting upon feedback. Regularly demonstrating the software to stakeholders and actively listening to their input allows the team to make necessary changes promptly. By adapting the development process based on feedback, XP ensures that the project aligns with the evolving needs and expectations of the stakeholders.
4. Respect
XP promotes a culture of respect among team members. Each individual is valued and given the respect they deserve as a crucial part of the team. Management acknowledges and supports the team’s right to accept responsibility and have authority over their own work, fostering an environment of trust and empowerment.
5. Courage
XP encourages a fearless approach to software development. Instead of dwelling on potential failures (or documenting them), the team focuses on planning for success. The collaborative nature of XP ensures that no team member ever works alone, fostering a sense of collective responsibility and providing the courage to take risks.
6. Harmony with Values
XP emphasizes that true harmony with values is achieved when team members are genuinely satisfied with their work. Admittedly, I know that for most this is a rare transition state - but XP aims to stay in this spot as long as possible. Just try to remember aligning from time to time the team’s actions and decisions with these core values.
Managing Goals Instead of Activities
We are now slowly descending from our initial 10000 feet view into the practical details of the development process.
In traditional software development processes, activities such as analysis, design, coding, testing, and production are typically completed in a sequence (but each simultaneously for all requirements). XP takes a different approach by prioritizing the completion of features based on their importance - which means going through all stages (analysis, design, etc.) for just one feature at a time. This flexibility allows the team to adapt to changing requirements and deliver incremental value throughout the project.
While this approach may require ongoing efforts to maintain code and design quality, it offers several cost and effort efficiencies. By focusing on delivering valuable features early, XP enables faster feedback cycles and helps identify and address potential issues sooner.
The Planning and Feedback Loop
To ensure effective project management, XP follows a loop of activities that span various time frames. These include:
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Release Plan (Months): The team creates a high-level plan that outlines the features and functionalities to be delivered in the next release. This plan provides a roadmap for the project’s progression over months.
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Iteration Plan (Weeks): XP divides the development process into short iterations, typically lasting a few weeks. During each iteration, the team selects a set of features from the release plan and plans the specific tasks required to implement them.
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Acceptance Test (Days): The team agrees on and designs acceptance tests to ensure that it meets the stakeholders’ requirements.
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Stand-Up Meeting and Pair Negotiation (Hours): Depending on the time criticality, regular or “on-demand” stand-up meetings are held to keep the team synchronized and address any obstacles or challenges. In these meetings, pairs and tasks are negotiated to facilitate effective collaboration and decision-making between team members.
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Pair Programming (Minutes): Developers work in pairs, fostering knowledge sharing, code review, and constant feedback. Pair programming not only enhances code quality but also improves the overall productivity and learning within the team. It starty by writing unit tests for individual code components before writing any other code (aka test driven development). Only after that, pairs work on implementing the actual feature.
By following this planning and feedback loop, XP ensures that all stakeholders are involved and receive the necessary feedback at various stages of the project. Developers receive feedback through pair programming and regular interactions, managers gain insights into progress and obstacles through daily meetings, and customers provide feedback through acceptance tests and during demonstrations.
Class, Responsibility, and Collaboration (CRC) Cards
To facilitate the design of complex solutions, you can use Class, Responsibility, and Collaboration (CRC) cards in a workshop-like session with all dev-team members. These cards capture essential information about the classes in the system, their responsibilities, and the collaborating classes. The CRC card structure typically includes:
- Class Name: The name of the object or class being represented.
- Responsibilities: The tasks and functions that the class is responsible for.
- Collaborating Classes: Other classes that interact and collaborate with the represented class.
CRC cards help visualize the relationships between different classes and aid in designing cohesive and maintainable software systems. Initially, a full set of CRC cards is created to establish the initial design. As the project progresses, the focus shifts to using cards with class names only, reducing the need for detailed cards during the ongoing development process.
The Customer’s Crucial Role
In XP, the customer plays a pivotal role throughout the software development process. The customer actively participates by writing user stories, prioritizing them, and negotiating which stories will be included in the next release. This collaborative approach reduces the reliance on detailed specifications and fosters a shared understanding of the project requirements. If there is no prioritization happening, or no time for taking part in joint sessions, something is wrong.
Additionally, the customer continuously tests the software and provides valuable feedback, ensuring that the end product aligns with their expectations. By actively involving the customer, XP maximizes efficiency and minimizes the risk of delivering a system that fails to meet the customer’s needs. If there is no time for continuous testing, something is wrong.
The customer’s involvement requires a significant investment of time but results in substantial time savings by eliminating the need for extensive documentation and reducing the chances of building an uncooperative system.
Final words
In conclusion, Extreme Programming (XP) offers a highly collaborative and iterative approach to software project management. By embracing simplicity, effective communication, feedback-driven development, respect, courage, and continuous customer involvement, XP empowers development teams to deliver high-quality software that meets stakeholder expectations. With its emphasis on adaptability and responsiveness, XP remains a valuable methodology in today’s dynamic and evolving tech landscape.
And remember, as an XP practitioner, true harmony with your values is achieved when you find happiness in your work.