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<td class="back"><a id="top"></a><a href="s3.4.c.html" rel="prev">&lt;&lt;&nbsp;&sect;3.4.(c)&nbsp;Warning levels</a></td>
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<div class="breadcrumb"><a class="nav" href="s3.html" rel="section">&sect;3&nbsp;Callout Binding</a>&nbsp;&gt;&nbsp;<a class="nav" href="s3.4.html" rel="section">&sect;3.4&nbsp;Overriding access restrictions</a></div>
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<h4 class="subsect">&sect;3.4.(d)&nbsp;<span class="title">Private methods from super classes</span><a class="img" href="s3.4.d.html"
title="PermaLink to (d)&nbsp;Private methods from super classes"><img style="vertical-align:text-top;margin-left:5px;" src="../images/permalink.png"
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<p>If a callout binding shall bind to a private base method, that method
must be defined in the exact base class to which the current role
class is bound using <code>playedBy</code>. I.e., for private methods
<a href="s3.1.d.html"
title="&sect;3.1.(d)&nbsp;Inheritance of role method declarations"
class="sect">&sect;3.1.(d)</a> does not hold.
<br />
The same holds for private base fields (see below).
<br />
If a private base feature must indeed be callout-bound, a role class
must be defined that is played by the exact base class defining the
private feature. Another role bound to a sub-base-class can then
be defined as a sub class of the first role. It will inherit the
callout binding and through this it can access the desired feature.
</p>
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<tr class="line odd">
<td class="ln">1</td>
<td><pre><b>public</b> <b>class</b> SuperBase {</pre></td>
</tr>
<tr class="line even">
<td class="ln">2</td>
<td><pre> <em><b>private</b> <b>int</b> secret;</em></pre></td>
</tr>
<tr class="line odd">
<td class="ln">3</td>
<td><pre>}</pre></td>
</tr>
<tr class="line even">
<td class="ln">4</td>
<td><pre><b>public</b> <b>class</b> SubBase <b>extends</b> SuperBase { <span class="comment">/* details omitted */</span> }</pre></td>
</tr>
<tr class="line odd">
<td class="ln">5</td>
<td><pre><b>public</b> <b>team</b> <b>class</b> MyTeam {</pre></td>
</tr>
<tr class="line even">
<td class="ln">6</td>
<td><pre> <b>protected</b> <b>class</b> SuperRole <b>playedBy</b> SuperBase {</pre></td>
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<tr class="line odd">
<td class="ln">7</td>
<td><pre> <b>int</b> steal() <b>-&gt;</b> <b>get</b> <b>int</b> <em>secret</em>; <span class="comment">// <span class="green"><strong>OK</strong></span></span></pre></td>
</tr>
<tr class="line even">
<td class="ln">8</td>
<td><pre> }</pre></td>
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<tr class="line odd">
<td class="ln">9</td>
<td><pre> <b>protected</b> <b>class</b> SubRole <b>extends</b> SuperRole <b>playedBy</b> SubBase {</pre></td>
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<tr class="line even">
<td class="ln">10</td>
<td><pre> <b>int</b> steal() <b>-&gt;</b> <b>get</b> <b>int</b> <em>secret</em>; <span class="comment">// <span class="error"><strong>illegal!</strong></span></span></pre></td>
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<tr class="line odd">
<td class="ln">11</td>
<td><pre> }</pre></td>
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<td class="ln">12</td>
<td><pre>}</pre></td>
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<div class="breadcrumb"><a class="nav" href="s3.html" rel="section">&sect;3&nbsp;Callout Binding</a>&nbsp;&gt;&nbsp;<a class="nav" href="s3.4.html" rel="section">&sect;3.4&nbsp;Overriding access restrictions</a></div>
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OT/J version 1.3 &mdash; last modified: 2010-06-08
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