blob: dd2506ab141020353507f7b33d56082a0e8017fc [file] [log] [blame]
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "../xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<link rel="stylesheet" type="text/css" href="../css/ot.css" />
<link rel="stylesheet" type="text/css" href="../css/otjld.css" />
<title>OT/J Language Definition v1.3</title>
</head>
<body class="otdt">
<div id="content">
<table class="nav">
<tr>
<td class="back"><a id="top"></a><a href="s4.2.c.html" rel="prev">&lt;&lt;&nbsp;&sect;4.2.(c)&nbsp;Replacing composition</a></td>
<td class="top"><a href="index.html" rel="contents">&uarr;&nbsp;Table of Contents&nbsp;&uarr;</a></td>
<td class="next"></td>
</tr>
</table>
<div class="breadcrumb"><a class="nav" href="s4.html" rel="section">&sect;4&nbsp;Callin Binding</a>&nbsp;&gt;&nbsp;<a class="nav" href="s4.2.html" rel="section">&sect;4.2&nbsp;Callin modifiers (before, after, replace)</a></div>
<div class="subsect depth3" id="s4.2.d">
<h4 class="subsect">&sect;4.2.(d)&nbsp;<span class="title">Callin methods</span><a class="img" href="s4.2.d.html" title="PermaLink to (d)&nbsp;Callin methods"><img style="vertical-align:text-top;margin-left:5px;" src="../images/permalink.png"
alt="" /></a></h4>
<p>Role methods to be bound by a callin replacement binding must have
the modifier <code>callin</code>. This modifier is only allowed for methods
of a role class.<br />
A method with the <code>callin</code> modifier can only be called
</p>
<ul>
<li>via a callin replace binding</li>
<li>by a <code>super</code> or <code>tsuper</code> call from an overriding callin method.
</li>
</ul>
<p>It is illegal for a <code>callin</code> method
</p>
<ul>
<li>to be called directly,</li>
<li>to be bound using a callout binding, and</li>
<li>to be bound to a base method using a <code>before</code> or <code>after</code> callin binding.
</li>
</ul>
<p>Despite these rules a second level role &mdash; which is played by the current role &mdash;
can intercept the execution of a callin method using any form of callin binding.</p>
<p>A callin method cannot override a regular method and vice versa, however,
overriding one callin method with another callin method is legal and
dynamic binding applies to callin method just like regular methods.
<br />
A callin method must not declare its visibility using any of the modifiers <code>public</code>,
<code>protected</code> or <code>private</code>. Since callin methods can only be invoked via callin bindings
such visibility control would not be useful.
</p>
</div>
<table class="nav">
<tr>
<td class="back"><a href="s4.2.c.html" rel="prev">&lt;&lt;&nbsp;&sect;4.2.(c)&nbsp;Replacing composition</a></td>
<td class="top"><a href="index.html" rel="contents">&uarr;&nbsp;Table of Contents&nbsp;&uarr;</a></td>
<td class="next"></td>
</tr>
</table>
<div class="breadcrumb"><a class="nav" href="s4.html" rel="section">&sect;4&nbsp;Callin Binding</a>&nbsp;&gt;&nbsp;<a class="nav" href="s4.2.html" rel="section">&sect;4.2&nbsp;Callin modifiers (before, after, replace)</a></div>
</div>
<div id="footer">
<hr /><a class="w3c img" href="http://jigsaw.w3.org/css-validator/check/referer"
shape="rect"><img src="../images/valid-css2-blue.png" alt="Valid CSS!" height="31" width="88" /></a><a class="w3c img" href="http://validator.w3.org/check?uri=referer" shape="rect"><img src="../images/valid-xhtml10-blue.png" alt="Valid XHTML 1.0 Strict" height="31"
width="88" /></a><address>&copy; Stephan Herrmann, Christine Hundt, Marco Mosconi</address>
OT/J version 1.3 &mdash; last modified: 2011-05-12
</div>
</body>
</html>