| <?xml version="1.0" encoding="UTF-8"?> |
| <org.eclipse.epf.uma:ContentDescription xmi:version="2.0" |
| xmlns:xmi="http://www.omg.org/XMI" xmlns:org.eclipse.epf.uma="http://www.eclipse.org/epf/uma/1.0.5/uma.ecore" |
| xmlns:epf="http://www.eclipse.org/epf" epf:version="1.5.0" xmi:id="-pQrBSyxJHLLodLbS4R_Zdw" |
| name="new_guideline,_qq0GMAXkEduj_7BEUj1JfQ" guid="-pQrBSyxJHLLodLbS4R_Zdw" changeDate="2007-05-31T09:39:37.540-0700" |
| version="7.1.0"> |
| <mainDescription><h3>
 |
| Use Case Formats
 |
| </h3>
 |
| <p>
 |
| The level of detail required in use cases differs from project to project, and even between use cases and scenarios
 |
| within the same project.&nbsp; A use case format that works in one situation may be totally unsuited for
 |
| another.&nbsp;The key to maximizing efficiency and effectiveness is to capture the right amount of detail for each
 |
| particular use case and scenario.&nbsp;(See <a class="elementLinkWithUserText" href="./../../../openup/guidances/supportingmaterials/references_6CCF393.html#ADO04" guid="_9ToeIB83Edqsvps02rpOOg">[ADO04]</a> for more information on use case formats.)
 |
| </p>
 |
| <p>
 |
| Some use cases need a high degree of detail. If the writers used a template, then they filled out all or almost all of
 |
| its fields for each use case. High-detail use cases are best suited complex, novel, or safety-critical functionality,
 |
| such as that found in flight control systems, telephone switches, and so forth where the risk of misinterpretation is
 |
| high.
 |
| </p>
 |
| <p>
 |
| Other use cases need less detail. If the writers used a template, then they may have left many of the fields blank.
 |
| Low-detail use cases are best suited for well understood, low complexity or less safety-critical functionality where
 |
| most of the stakeholders have a strong background in the problem domain and the risk of misinterpretation is low. In
 |
| these cases, simple brief descriptions or step-by-step outlines suffice.
 |
| </p>
 |
| <p>
 |
| Furthermore, not all scenarios are created equally.&nbsp; Within the same use case, some scenarios are very well
 |
| understood and a brief description is sufficient to ensure un-ambiguous interpretation.&nbsp;&nbsp; Other scenarios may
 |
| require more detail to capture the essential behavior un-ambiguously.
 |
| </p>
 |
| <p>
 |
| Finally, as explained in <a class="elementLinkWithType" href="./../../../openup/guidances/guidelines/detail_ucs_and_scenarios_6BC56BB7.html" guid="_4BJ_YCxSEdqjsdw1QLH_6Q">Guideline: Detail Use Cases and Scenarios</a>, it makes sense to write use cases
 |
| iteratively. Starting with the basic details, you can then identify the various alternative and error paths that the
 |
| use case might follow so that you can evaluate, rearrange, or eliminate them, and then elaborate or fill in the details
 |
| of the&nbsp;remaining scenarios.
 |
| </p>
 |
| <p>
 |
| Write use cases and scenarios in one or more of the following formats, progressively, until you reach the level of
 |
| detail required:
 |
| </p>
 |
| <ul>
 |
| <li>
 |
| <strong>Use-case model overview:</strong> A format for understanding the “big-picture”
 |
| </li>
 |
| <li>
 |
| <strong>Use-case brief descriptions:</strong> A format for writing summary use cases
 |
| </li>
 |
| <li>
 |
| <strong>Step-by-step outlines:</strong> A format for writing less formal, low-ceremony use cases
 |
| </li>
 |
| <li>
 |
| <strong>Fully detailed:</strong> A format for writing more formal, high-ceremony use cases
 |
| </li>
 |
| </ul>
 |
| <h4>
 |
| Use-Case Model Overview
 |
| </h4>
 |
| <p>
 |
| Create a use-case model overview, which captures actors and associated use cases.
 |
| </p>
 |
| <ul>
 |
| <li>
 |
| Start by identifying the list of actors who will use the system, and then identify at least one goal for each.
 |
| Actors without goals indicate that you haven’t adequately defined the system. The actor is beyond the system’s
 |
| scope, doesn’t belong in the system, or is part of another actor.
 |
| </li>
 |
| <li>
 |
| Likewise, leftover goals can indicate that the system is too complex and you're trying to accomplish too much, or
 |
| that you haven’t adequately defined all of the necessary actors. Carefully evaluate the leftovers to see if you are
 |
| just overlooking some detail, or whether they don’t belong in the system.
 |
| </li>
 |
| <li>
 |
| Remove unassociated actors and goals from the model.
 |
| </li>
 |
| </ul>
 |
| <p>
 |
| Sometimes, this overview may provide enough information to serve as the use-case model for very small,
 |
| high-communicating, low-ceremony project teams. Usually, the use-case model overview is the first step of identifying
 |
| use cases and system boundaries.
 |
| </p>
 |
| <h4>
 |
| Use-Case brief descriptions
 |
| </h4>
 |
| <p>
 |
| Write two to four sentences per use case, capturing key activities and key-extension handling.
 |
| </p>
 |
| <ul>
 |
| <li>
 |
| Expand the high priority use-cases by writing a two- to four-sentence use cases for each entry in the list.
 |
| </li>
 |
| <li>
 |
| Briefly describe each use case’s main&nbsp;scenario and most important extensions.
 |
| </li>
 |
| <li>
 |
| Include enough information to eliminate ambiguity for at least the main&nbsp;scenario.
 |
| </li>
 |
| </ul>
 |
| <h4>
 |
| Step-by-step outlines&nbsp;
 |
| </h4>
 |
| <p>
 |
| Write the step-by-step outline which describes the interaction between the actor(s) and the system.
 |
| </p>
 |
| <ul>
 |
| <li>
 |
| Key scenarios are detailed to describe the interaction
 |
| </li>
 |
| <li>
 |
| Triggering events are specified
 |
| </li>
 |
| <li>
 |
| Information exchanged&nbsp;is described
 |
| </li>
 |
| </ul>
 |
| <h4>
 |
| Fully Detailed
 |
| </h4>
 |
| <p>
 |
| Complete all sections of the <a class="elementLink" href="./../../../openup/guidances/templates/uc_specification_E97E98B0.html" guid="_0cpNwMlgEdmt3adZL5Dmdw">Use-Case Specification</a>&nbsp;template.
 |
| </p>
 |
| <ul>
 |
| <li>
 |
| The main scenario is detailed
 |
| </li>
 |
| <li>
 |
| All alternative flows are identified and detailed
 |
| </li>
 |
| <li>
 |
| Special requirements are complete and un-ambiguous
 |
| </li>
 |
| <li>
 |
| Pre- and Post-conditions are specified.
 |
| </li>
 |
| </ul></mainDescription> |
| </org.eclipse.epf.uma:ContentDescription> |
