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<title>OT/J Language Definition v1.3.1</title>
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<td class="back"><a id="top"></a><a href="s1.2.3.html" rel="prev">&lt;&lt;&nbsp;&sect;1.2.3&nbsp;Protected roles</a></td>
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<div class="breadcrumb"><a class="nav" href="s1.html" rel="section">&sect;1&nbsp;Teams and Roles</a>&nbsp;&gt;&nbsp;<a class="nav" href="s1.2.html" rel="section">&sect;1.2&nbsp;Role classes and objects</a></div>
<div class="sect depth3" id="s1.2.4">
<h3 class="sect">&sect;1.2.4&nbsp;Type tests and casts<a class="img" href="s1.2.4.html"
title="PermaLink to &sect;1.2.4&nbsp;Type tests and casts"><img style="vertical-align:text-top;margin-left:5px;" src="../images/permalink.png"
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<p>In accordance with <a href="s1.2.2.e.html" title="&sect;1.2.2.(e)&nbsp;Conformance" class="sect">&sect;1.2.2.(e)</a>, in OT/J
the <code>instanceof</code> operator and type casts have extended semantics for roles.
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<h4 class="subsect">(a)&nbsp;<span class="title">instanceof</span><a class="img" href="s1.2.4.a.html" title="PermaLink to (a)&nbsp;instanceof"><img style="vertical-align:text-top;margin-left:5px;" src="../images/permalink.png"
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<p>For role types the <code>instanceof</code> operator yields true only if
both components of the type match: the dynamic role type must be compatible
to the given static type, and also type anchors must be the same instance.
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<div class="subsect depth4" id="s1.2.4.b">
<h4 class="subsect">(b)&nbsp;<span class="title">Casting</span><a class="img" href="s1.2.4.b.html" title="PermaLink to (b)&nbsp;Casting"><img style="vertical-align:text-top;margin-left:5px;" src="../images/permalink.png"
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<p>Casts may also fail if the casted expression is anchored to a different
team instance than the cast type. Such failure is signaled by a
<code>org.objectteams.RoleCastException</code>.
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<div class="subsect depth4" id="s1.2.4.c">
<h4 class="subsect">(c)&nbsp;<span class="title">Class literal</span><a class="img" href="s1.2.4.c.html" title="PermaLink to (c)&nbsp;Class literal"><img style="vertical-align:text-top;margin-left:5px;" src="../images/permalink.png"
alt="" /></a></h4>
<p>A class literal of form <code>R.class</code> is dynamically bound to the class <code>R</code>
visible in the current instance context. Using a class literal for a role outside its
enclosing team instance (see <a href="s1.2.2.html" title="&sect;1.2.2&nbsp;Externalized roles" class="sect">&sect;1.2.2</a>) requires the following syntax:
</p>
<div class="listing plain"><pre>RoleClass<em>&lt;@teamAnchor&gt;</em><strong>.class</strong></pre></div>
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<div class="breadcrumb"><a class="nav" href="s1.html" rel="section">&sect;1&nbsp;Teams and Roles</a>&nbsp;&gt;&nbsp;<a class="nav" href="s1.2.html" rel="section">&sect;1.2&nbsp;Role classes and objects</a></div>
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OT/J version 1.3.1 &mdash; last modified: 2013-05-28
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