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| <td class="back"><a id="top"></a><a href="s2.5.a.html" rel="prev"><< §2.5.(a) Using abstract classes for creation</a></td> |
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| <div class="breadcrumb"><a class="nav" href="s2.html" rel="section">§2 Role Binding</a> > <a class="nav" href="s2.5.html" rel="section">§2.5 Abstract Roles</a></div> |
| <div class="subsect depth3" id="s2.5.b"> |
| <h4 class="subsect">§2.5.(b) <span class="title">Relevant roles</span><a class="img" href="s2.5.b.html" title="PermaLink to (b) Relevant roles"><img style="vertical-align:text-top;margin-left:5px;" src="../images/permalink.png" |
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| <p>A team must be marked <code>abstract</code> if one of its <strong>relevant roles</strong> is abstract. |
| <br /> |
| A role is relevant in this sense if |
| |
| </p> |
| <ul> |
| <li>the role class is public <em>or if</em></li> |
| <li>an explicit <code>new</code> expression |
| would require to create instances of the role class, <em>or if</em></li> |
| <li>any of the lifting methods of the enclosing team |
| would require to create instances of the role class.<br /> |
| A role is irrelevant with respect to lifting |
| if either of the following holds: |
| |
| <ul> |
| <li>It is not bound to a base class, neither directly nor |
| by an inherited <code>playedBy</code> clause. |
| </li> |
| <li>It has a sub-role without a <code>playedBy</code> clause. |
| </li> |
| <li>It is bound to an abstract base class, and for all concrete |
| sub-classes of the base class, a binding to a more specific role class exists. |
| </li> |
| </ul> |
| </li> |
| </ul> |
| <p>If neither property, relevance nor irrelevance, can be shown for an abstract role, |
| a warning is given in case the enclosing team is not abstract. |
| |
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| <div class="breadcrumb"><a class="nav" href="s2.html" rel="section">§2 Role Binding</a> > <a class="nav" href="s2.5.html" rel="section">§2.5 Abstract Roles</a></div> |
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| width="88" /></a><address>© Stephan Herrmann, Christine Hundt, Marco Mosconi</address> |
| OT/J version 1.3 — last modified: 2010-06-08 |
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