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| <h1 xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0"> | |
| OclVoid | |
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| <div class="section" title="OclVoid"> | |
| <div class="titlepage"> | |
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| <div> | |
| <h2 class="title" style="clear: both"> | |
| <a name="OclVoid"></a> | |
| <span class="bold"><strong> | |
| <code class="code">OclVoid</code> | |
| </strong></span> | |
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| <p>The type OclVoid is a type that conforms to all other types except OclInvalid. | |
| It has one single instance, identified as | |
| <code class="code">null</code>, that corresponds with the UML LiteralNull value specification. | |
| Any property call applied on | |
| <code class="code">null</code> results in | |
| <code class="code">invalid</code>, except for the | |
| oclIsUndefined(), oclIsInvalid(), =(OclAny) and <>(OclAny) operations. | |
| However, by virtue of the implicit conversion to a collection literal, | |
| an expression evaluating to | |
| <code class="code">null</code> can be used as source of collection operations (such as ‘isEmpty’). | |
| If the source is the | |
| <code class="code">null</code> literal, it is implicitly converted to Bag{}. | |
| </p> | |
| <p>OclVoid is itself an instance of the metatype VoidType.</p> | |
| <p>conformsTo | |
| <a class="link" href="OclAny.html" title="OclAny"> | |
| <code class="code">OclAny</code> | |
| </a> | |
| </p> | |
| <p> | |
| <span class="bold"><strong>Operations</strong></span> | |
| </p> | |
| <p> | |
| <code class="code">=(object2 : OclSelf[?]) : Boolean[1]</code> | |
| precedence: | |
| <code class="code">EQUALITY</code> | |
| </p> | |
| <p>Redefines the OclAny operation, returning | |
| <code class="code">true</code> if object is | |
| <code class="code">null</code>, | |
| <code class="code">invalid</code> | |
| if object is | |
| <code class="code">invalid</code>, | |
| <code class="code">false</code> otherwise. | |
| </p> | |
| <p> | |
| <code class="code"><>(object2 : OclSelf[?]) : Boolean[1]</code> | |
| precedence: | |
| <code class="code">EQUALITY</code> | |
| </p> | |
| <p> | |
| <code class="code">allInstances() : Set(OclSelf[*|?])</code> | |
| </p> | |
| <p>Returns | |
| <code class="code">Set{null}</code>. | |
| </p> | |
| <p> | |
| <code class="code">and(b : Boolean[?]) : Boolean[?]</code> | |
| precedence: | |
| <code class="code">AND</code> | |
| </p> | |
| <p> | |
| <code class="code">implies(b : Boolean[?]) : Boolean[?]</code> | |
| precedence: | |
| <code class="code">IMPLIES</code> | |
| </p> | |
| <p> | |
| <code class="code">oclAsSet() : Set(OclSelf)</code> | |
| </p> | |
| <p> | |
| <code class="code">oclIsInvalid() : Boolean[1] validating</code> | |
| </p> | |
| <p> | |
| <code class="code">oclIsUndefined() : Boolean[1] validating</code> | |
| </p> | |
| <p> | |
| <code class="code">or(b : Boolean[?]) : Boolean[?]</code> | |
| precedence: | |
| <code class="code">OR</code> | |
| </p> | |
| <p> | |
| <code class="code">toString() : String[1]</code> | |
| </p> | |
| <p>Returns | |
| <code class="code">null</code>. | |
| </p> | |
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