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php-manual-en-5.5.7-1.mga4.noarch.rpm

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  <title>Final Keyword</title>

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</div><hr /><div id="language.oop5.final" class="sect1">
  <h2 class="title">Final Keyword</h2>
  <p class="para">
   PHP 5 introduces the final keyword, which prevents child classes from
   overriding a method by prefixing the definition with <em class="emphasis">final</em>. If the class
   itself is being defined final then it cannot be extended.
  </p>
  <p class="para">
   <div class="example" id="example-223">
    <p><strong>Example #1 Final methods example</strong></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">class&nbsp;</span><span style="color: #0000BB">BaseClass&nbsp;</span><span style="color: #007700">{<br />&nbsp;&nbsp;&nbsp;public&nbsp;function&nbsp;</span><span style="color: #0000BB">test</span><span style="color: #007700">()&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"BaseClass::test()&nbsp;called\n"</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;}<br />&nbsp;&nbsp;&nbsp;<br />&nbsp;&nbsp;&nbsp;final&nbsp;public&nbsp;function&nbsp;</span><span style="color: #0000BB">moreTesting</span><span style="color: #007700">()&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"BaseClass::moreTesting()&nbsp;called\n"</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;}<br />}<br /><br />class&nbsp;</span><span style="color: #0000BB">ChildClass&nbsp;</span><span style="color: #007700">extends&nbsp;</span><span style="color: #0000BB">BaseClass&nbsp;</span><span style="color: #007700">{<br />&nbsp;&nbsp;&nbsp;public&nbsp;function&nbsp;</span><span style="color: #0000BB">moreTesting</span><span style="color: #007700">()&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"ChildClass::moreTesting()&nbsp;called\n"</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;}<br />}<br /></span><span style="color: #FF8000">//&nbsp;Results&nbsp;in&nbsp;Fatal&nbsp;error:&nbsp;Cannot&nbsp;override&nbsp;final&nbsp;method&nbsp;BaseClass::moreTesting()<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
   </div>

  </div>
  </p>
  <p class="para">
   <div class="example" id="example-224">
    <p><strong>Example #2 Final class example</strong></p>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">final&nbsp;class&nbsp;</span><span style="color: #0000BB">BaseClass&nbsp;</span><span style="color: #007700">{<br />&nbsp;&nbsp;&nbsp;public&nbsp;function&nbsp;</span><span style="color: #0000BB">test</span><span style="color: #007700">()&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"BaseClass::test()&nbsp;called\n"</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;}<br /><br />&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;Here&nbsp;it&nbsp;doesn't&nbsp;matter&nbsp;if&nbsp;you&nbsp;specify&nbsp;the&nbsp;function&nbsp;as&nbsp;final&nbsp;or&nbsp;not<br />&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">final&nbsp;public&nbsp;function&nbsp;</span><span style="color: #0000BB">moreTesting</span><span style="color: #007700">()&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"BaseClass::moreTesting()&nbsp;called\n"</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;}<br />}<br /><br />class&nbsp;</span><span style="color: #0000BB">ChildClass&nbsp;</span><span style="color: #007700">extends&nbsp;</span><span style="color: #0000BB">BaseClass&nbsp;</span><span style="color: #007700">{<br />}<br /></span><span style="color: #FF8000">//&nbsp;Results&nbsp;in&nbsp;Fatal&nbsp;error:&nbsp;Class&nbsp;ChildClass&nbsp;may&nbsp;not&nbsp;inherit&nbsp;from&nbsp;final&nbsp;class&nbsp;(BaseClass)<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

   </div>
  </p>
  <blockquote class="note"><p><strong class="note">Note</strong>: 
   <span class="simpara">
    Properties cannot be declared final, only classes and methods 
    may be declared as final.
   </span>
  </p></blockquote>
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