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| <div class="breadcrumb"><a class="nav" href="s5.html" rel="section">§5 Team Activation</a> > <a class="nav" href="s5.4.html" rel="section">§5.4 Guard predicates</a> > <a class="nav" href="s5.4.1.html" rel="section">§5.4.1 Regular guards</a></div> |
| <div class="subsect depth4" id="s5.4.1.a"> |
| <h4 class="subsect">§5.4.1.(a) <span class="title">Method binding guards</span><a class="img" href="s5.4.1.a.html" |
| title="PermaLink to (a) Method binding guards"><img style="vertical-align:text-top;margin-left:5px;" src="../images/permalink.png" |
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| <p>A guard may be attached to a callin method binding as in: |
| |
| </p> |
| <div class="listing plain"><pre><b>void</b> roleMethod(<b>int</b> ir) <b><-</b> <b>after</b> <b>void</b> baseMethod(<b>int</b> ib) |
| <b>when</b> (ir > MyTeam.this.threshold);</pre></div> |
| <p>Such a guard only affects the callin binding to which it is attached, |
| i.e., this specific callin binding is only effective, |
| if the predicate evaluates to <code>true</code>. |
| <br /> |
| The following values are within the scope of the predicate expression, |
| and thus can be used to express the condition: |
| |
| </p> |
| <ul> |
| <li>The role instance denoted by <code>this</code>.<br /> |
| Features of the role instance can also be accessed relative to |
| <code>this</code> with or without explicit qualifying <code>this</code>. |
| |
| </li> |
| <li>The team instance denoted by a qualified this reference as in |
| <code>MyTeam.this</code>. |
| |
| </li> |
| <li>If the callin binding includes signatures (as in the example above): |
| Parameters of the role method.<br /> |
| If parameter mappings are involved, they will be evaluated before evaluating the guard. |
| |
| </li> |
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| <div class="breadcrumb"><a class="nav" href="s5.html" rel="section">§5 Team Activation</a> > <a class="nav" href="s5.4.html" rel="section">§5.4 Guard predicates</a> > <a class="nav" href="s5.4.1.html" rel="section">§5.4.1 Regular guards</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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