Develop or use software so you can test a hypothesis, learn information needed to make a design decision, prove a quality attribute, or gain experience. Sometimes the only way to learn what you need to know is to do it yourself. This adage is especially true of technology and frameworks.

We prototype to learn when we need to figure out how to do something or how something works. We prototype to decide when we need to gather information that will help us choose between multiple options.

Building a prototype to decide is like running an experiment. The technology or pattern under investigation is hypothesized to solve a specific design problem. The purpose of the prototype is to test the hypothesis.

Benefits

• Gather information through firsthand experience.
• Generate data to use in decision making.
• Allow stakeholders to experience a part of the system.
• Learn how something works quickly and inexpensively.

Description

The difference between a useless prototype and overdoing it is a razor-thin line. To increase your chances of success when prototyping, you need a plan. Let’s look at what is involved in creating a prototyping plan.

1. Define the learning objectives and scope for the prototype. What questions will this prototype help you answer?

2. Decide on the prototype’s budget and establish a delivery time line. When will you pull the plug on the prototype? How much are you willing to spend to meet the learning objectives? Limit costs and time as much as possible.

3. Decide how the outcomes will be delivered. Who is the audience for the prototype and how will you share it? For example, will you share a demo, whitepaper, presentation, or something else?

The goal is always to implement the prototype as quickly and cheaply as possible. As the prototype comes together, review the implementation relative to the plan. Once you’ve achieved the objectives, the prototype is complete and it’s time to share the outcomes.

After the prototype is complete, perform the minimum clean-up necessary so it can be used again if required. Archive code and instructions for future reference.

Guidelines and Hints

• Look for ways to meet your learning objectives without writing software.

• Decide up front whether the prototype is evolutionary or throw-away.

• Keep tabs on the prototype implementers. Prototyping often requires that you trade quality for speed of delivery and completeness. This is a challenge for many developers who are proud of their craft.

• Time-box the prototype aggressively, but allow sufficient time to complete the work.

• Sketch out a high-level design for the prototype with the implementers before starting development.

Example

Here’s an example of prototyping to learn. The team needed to understand the performance limitations of specific Apache Solr APIs. To learn this, a single developer over the course of one week developed a simple test driver using Apache JMeter,^[47] ran several load tests, collected data, and wrote a two-page report summarizing the findings. Using Apache JMeter let the team quickly gather data with minimal effort.

Here’s an example of prototyping to choose. The team needed to select a server-side web framework. To help them decide, the team implemented a simple blog application using the top two frameworks. The activity was time-boxed to two days. At the end of the second day, the team discussed pros and cons of each framework based on their experiences and chose a framework.