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| <td class="back"><a id="top"></a><a href="s2.1.2.c.html" rel="prev"><< §2.1.2.(c) Base class decapsulation</a></td> |
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| <td class="next"><a href="s2.1.2.e.html" rel="next">§2.1.2.(e) No free type parameters >></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="s2.1.html" rel="section">§2.1 playedBy relation</a> > <a class="nav" href="s2.1.2.html" rel="section">§2.1.2 Legal base classes</a></div> |
| <div class="subsect depth4" id="s2.1.2.d"> |
| <h4 class="subsect">§2.1.2.(d) <span class="title">Base imports</span><a class="img" href="s2.1.2.d.html" title="PermaLink to (d) Base imports"><img style="vertical-align:text-top;margin-left:5px;" src="../images/permalink.png" |
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| <p>If the main type in a file denotes a team, the modifier <code>base</code> can be applied to an import in order to specify that this type |
| should be imported for application as a base type only. Example: |
| |
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| <td class="ln">1</td> |
| <td><pre><em><b>import</b> base</em> some.pack.MyBase;</pre></td> |
| </tr> |
| <tr class="line even"> |
| <td class="ln">2</td> |
| <td><pre><b>public</b> <b>team</b> <b>class</b> MyTeam {</pre></td> |
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| <td class="ln">3</td> |
| <td><pre> <span class="comment">// simple name resolves to imported class:</span></pre></td> |
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| <td class="ln">4</td> |
| <td><pre> <b>protected</b> <b>class</b> MyRole <em><b>playedBy</b> MyBase</em> { } </pre></td> |
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| <td class="ln">5</td> |
| <td><pre> <span class="error"><em>MyBase</em> illegalDeclaration;</span> <span class="comment">// base import does not apply for this position</span></pre></td> |
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| <td class="ln">6</td> |
| <td><pre>}</pre></td> |
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| <p>Types imported by a base import can only be used in the same positions where also base class decapsulation (<a href="s2.1.2.c.html" title="§2.1.2.(c) Base class decapsulation" |
| class="sect">§2.1.2.(c)</a>) |
| is applicable.<br /> |
| It is recommended that a type mentioned after the keyword <code>playedBy</code> is always imported with the <code>base</code> modifier, otherwise the compiler |
| will give a warning.<br /> |
| Base imports create a scope that is disjoint from the normal scope. Thus, names that are imported as base will never clash |
| with normally visible names |
| (in contrast to <a href="s1.4.html" title="§1.4 Name clashes" class="sect">§1.4</a>). More specifically, it is not a problem to use a base class's name also for its role if a base import is used. |
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| <div class="breadcrumb"><a class="nav" href="s2.html" rel="section">§2 Role Binding</a> > <a class="nav" href="s2.1.html" rel="section">§2.1 playedBy relation</a> > <a class="nav" href="s2.1.2.html" rel="section">§2.1.2 Legal base classes</a></div> |
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| width="88" /></a><address>© Stephan Herrmann, Christine Hundt, Marco Mosconi</address> |
| OT/J version 1.3 — last modified: 2011-05-15 |
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