language.oop5.overloading.html

php的帮助文档,涉及到PHP的案例和基本语法,以及实际应用内容

   <p class="para">
    <i>__isset()</i> is triggered by calling
    <a href="function.isset.html" class="function">isset()</a> or <a href="function.empty.html" class="function">empty()</a>
    on inaccessible members.
   </p>

   <p class="para">
    <i>__unset()</i> is invoked when
    <a href="function.unset.html" class="function">unset()</a> is used on inaccessible members.
   </p>

   <p class="para">
    The <var class="varname">$name</var> argument is the name of the
    member being interacted with. The <i>__set()</i>
    method&#039;s <var class="varname">$value</var> argument specifies the
    value the <var class="varname">$name</var>&#039;ed member should be set
    to.
   </p>

   <p class="para">
    Member overloading only works in object context. These magic
    methods will not be triggered in static context. Therefore
    these methods can not be declared
    <a href="language.oop5.static.html" class="link">static</a>.
   </p>

   <div class="example">
    <p><b>Example #1 overloading with __get, __set, __isset and __unset example</b></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">MemberTest&nbsp;</span><span style="color: #007700">{<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">/**&nbsp;&nbsp;Location&nbsp;for&nbsp;overloaded&nbsp;data.&nbsp;&nbsp;*/<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">private&nbsp;</span><span style="color: #0000BB">$data&nbsp;</span><span style="color: #007700">=&nbsp;array();<br /><br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">/**&nbsp;&nbsp;Overloading&nbsp;not&nbsp;used&nbsp;on&nbsp;declared&nbsp;members.&nbsp;&nbsp;*/<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">public&nbsp;</span><span style="color: #0000BB">$declared&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">1</span><span style="color: #007700">;<br /><br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">/**&nbsp;&nbsp;Overloading&nbsp;only&nbsp;used&nbsp;on&nbsp;this&nbsp;when&nbsp;accessed&nbsp;outside&nbsp;the&nbsp;class.&nbsp;&nbsp;*/<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">private&nbsp;</span><span style="color: #0000BB">$hidden&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">2</span><span style="color: #007700">;<br /><br />&nbsp;&nbsp;&nbsp;&nbsp;public&nbsp;function&nbsp;</span><span style="color: #0000BB">__set</span><span style="color: #007700">(</span><span style="color: #0000BB">$name</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$value</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"Setting&nbsp;'$name'&nbsp;to&nbsp;'$value'\n"</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$this</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">data</span><span style="color: #007700">[</span><span style="color: #0000BB">$name</span><span style="color: #007700">]&nbsp;=&nbsp;</span><span style="color: #0000BB">$value</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br /><br />&nbsp;&nbsp;&nbsp;&nbsp;public&nbsp;function&nbsp;</span><span style="color: #0000BB">__get</span><span style="color: #007700">(</span><span style="color: #0000BB">$name</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"Getting&nbsp;'$name'\n"</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if&nbsp;(</span><span style="color: #0000BB">array_key_exists</span><span style="color: #007700">(</span><span style="color: #0000BB">$name</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$this</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">data</span><span style="color: #007700">))&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;</span><span style="color: #0000BB">$this</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">data</span><span style="color: #007700">[</span><span style="color: #0000BB">$name</span><span style="color: #007700">];<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<br /><br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">$trace&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">debug_backtrace</span><span style="color: #007700">();<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">trigger_error</span><span style="color: #007700">(<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #DD0000">'Undefined&nbsp;property&nbsp;via&nbsp;__get():&nbsp;'&nbsp;</span><span style="color: #007700">.&nbsp;</span><span style="color: #0000BB">$name&nbsp;</span><span style="color: #007700">.<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #DD0000">'&nbsp;in&nbsp;'&nbsp;</span><span style="color: #007700">.&nbsp;</span><span style="color: #0000BB">$trace</span><span style="color: #007700">[</span><span style="color: #0000BB">0</span><span style="color: #007700">][</span><span style="color: #DD0000">'file'</span><span style="color: #007700">]&nbsp;.<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #DD0000">'&nbsp;on&nbsp;line&nbsp;'&nbsp;</span><span style="color: #007700">.&nbsp;</span><span style="color: #0000BB">$trace</span><span style="color: #007700">[</span><span style="color: #0000BB">0</span><span style="color: #007700">][</span><span style="color: #DD0000">'line'</span><span style="color: #007700">],<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">E_USER_NOTICE</span><span style="color: #007700">);<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;</span><span style="color: #0000BB">null</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br /><br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">/**&nbsp;&nbsp;As&nbsp;of&nbsp;PHP&nbsp;5.1.0&nbsp;&nbsp;*/<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">public&nbsp;function&nbsp;</span><span style="color: #0000BB">__isset</span><span style="color: #007700">(</span><span style="color: #0000BB">$name</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"Is&nbsp;'$name'&nbsp;set?\n"</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;isset(</span><span style="color: #0000BB">$this</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">data</span><span style="color: #007700">[</span><span style="color: #0000BB">$name</span><span style="color: #007700">]);<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br /><br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">/**&nbsp;&nbsp;As&nbsp;of&nbsp;PHP&nbsp;5.1.0&nbsp;&nbsp;*/<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">public&nbsp;function&nbsp;</span><span style="color: #0000BB">__unset</span><span style="color: #007700">(</span><span style="color: #0000BB">$name</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;</span><span style="color: #DD0000">"Unsetting&nbsp;'$name'\n"</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;unset(</span><span style="color: #0000BB">$this</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">data</span><span style="color: #007700">[</span><span style="color: #0000BB">$name</span><span style="color: #007700">]);<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br /><br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">/**&nbsp;&nbsp;Not&nbsp;a&nbsp;magic&nbsp;method,&nbsp;just&nbsp;here&nbsp;for&nbsp;example.&nbsp;&nbsp;*/<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">public&nbsp;function&nbsp;</span><span style="color: #0000BB">getHidden</span><span style="color: #007700">()&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;</span><span style="color: #0000BB">$this</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">hidden</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br />}<br /><br /><br />echo&nbsp;</span><span style="color: #DD0000">"&lt;pre&gt;\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$obj&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">MemberTest</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$obj</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">a&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">1</span><span style="color: #007700">;<br />echo&nbsp;</span><span style="color: #0000BB">$obj</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">a&nbsp;</span><span style="color: #007700">.&nbsp;</span><span style="color: #DD0000">"\n\n"</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(isset(</span><span style="color: #0000BB">$obj</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">a</span><span style="color: #007700">));<br />unset(</span><span style="color: #0000BB">$obj</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">a</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(isset(</span><span style="color: #0000BB">$obj</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">a</span><span style="color: #007700">));<br />echo&nbsp;</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /><br />echo&nbsp;</span><span style="color: #0000BB">$obj</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">declared&nbsp;</span><span style="color: #007700">.&nbsp;</span><span style="color: #DD0000">"\n\n"</span><span style="color: #007700">;<br /><br />echo&nbsp;</span><span style="color: #DD0000">"Let's&nbsp;experiment&nbsp;with&nbsp;the&nbsp;private&nbsp;property&nbsp;named&nbsp;'hidden':\n"</span><span style="color: #007700">;<br />echo&nbsp;</span><span style="color: #DD0000">"Privates&nbsp;are&nbsp;visible&nbsp;inside&nbsp;the&nbsp;class,&nbsp;so&nbsp;__get()&nbsp;not&nbsp;used...\n"</span><span style="color: #007700">;<br />echo&nbsp;</span><span style="color: #0000BB">$obj</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">getHidden</span><span style="color: #007700">()&nbsp;.&nbsp;</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />echo&nbsp;</span><span style="color: #DD0000">"Privates&nbsp;not&nbsp;visible&nbsp;outside&nbsp;of&nbsp;class,&nbsp;so&nbsp;__get()&nbsp;is&nbsp;used...\n"</span><span style="color: #007700">;<br />echo&nbsp;</span><span style="color: #0000BB">$obj</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">hidden&nbsp;</span><span style="color: #007700">.&nbsp;</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>The above example will output:</p></div>
    <div class="example-contents"><pre>
<div class="cdata"><pre>
Setting &#039;a&#039; to &#039;1&#039;
Getting &#039;a&#039;
1

Is &#039;a&#039; set?
bool(true)
Unsetting &#039;a&#039;
Is &#039;a&#039; set?
bool(false)

1

Let&#039;s experiment with the private property named &#039;hidden&#039;:
Privates are visible inside the class, so __get() not used...
2
Privates not visible outside of class, so __get() is used...
Getting &#039;hidden&#039;


Notice:  Undefined property via __get(): hidden in &lt;file&gt; on line 70 in &lt;file&gt; on line 29
</pre></div>
    </pre></div>

   </div>
  </div>

  <div id="language.oop5.overloading.methods" class="sect2">
   <h3 class="title">Method overloading</h3>

   <div class="methodsynopsis dc-description">
    <span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <span class="methodname"><b><b>__call</b></b></span>
     ( <span class="methodparam"><span class="type">string</span> <tt class="parameter">$name</tt></span>
    , <span class="methodparam"><span class="type">array</span> <tt class="parameter">$arguments</tt></span>
    )</div>

   <div class="methodsynopsis dc-description">
    <span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <span class="methodname"><b><b>__callStatic</b></b></span>
     ( <span class="methodparam"><span class="type">string</span> <tt class="parameter">$name</tt></span>
    , <span class="methodparam"><span class="type">array</span> <tt class="parameter">$arguments</tt></span>
    )</div>


   <p class="para">
    <i>__call()</i> is triggered when invoking
    inaccessible methods in an object context.
   </p>

   <p class="para">
    <i>__callStatic()</i> is triggered when invoking
    inaccessible methods in a static context.
   </p>

   <p class="para">
    The <var class="varname">$name</var> argument is the name of the
    method being called. The <var class="varname">$arguments</var>
    argument is an enumerated array containing the parameters
    passed to the <var class="varname">$name</var>&#039;ed method.
   </p>

   <div class="example">
    <p><b>Example #2 overloading instantiated methods with __call and ___callStatic</b></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">MethodTest&nbsp;</span><span style="color: #007700">{<br />&nbsp;&nbsp;&nbsp;&nbsp;public&nbsp;function&nbsp;</span><span style="color: #0000BB">__call</span><span style="color: #007700">(</span><span style="color: #0000BB">$name</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$arguments</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;Note:&nbsp;value&nbsp;of&nbsp;$name&nbsp;is&nbsp;case&nbsp;sensitive.<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">echo&nbsp;</span><span style="color: #DD0000">"Calling&nbsp;object&nbsp;method&nbsp;'$name'&nbsp;"<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">.&nbsp;</span><span style="color: #0000BB">implode</span><span style="color: #007700">(</span><span style="color: #DD0000">',&nbsp;'</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$arguments</span><span style="color: #007700">).&nbsp;</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br /><br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">/**&nbsp;&nbsp;As&nbsp;of&nbsp;PHP&nbsp;5.3.0&nbsp;&nbsp;*/<br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">public&nbsp;static&nbsp;function&nbsp;</span><span style="color: #0000BB">__callStatic</span><span style="color: #007700">(</span><span style="color: #0000BB">$name</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$arguments</span><span style="color: #007700">)&nbsp;{<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;Note:&nbsp;value&nbsp;of&nbsp;$name&nbsp;is&nbsp;case&nbsp;sensitive.<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">echo&nbsp;</span><span style="color: #DD0000">"Calling&nbsp;static&nbsp;method&nbsp;'$name'&nbsp;"<br />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">.&nbsp;</span><span style="color: #0000BB">implode</span><span style="color: #007700">(</span><span style="color: #DD0000">',&nbsp;'</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$arguments</span><span style="color: #007700">).&nbsp;</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;<br />&nbsp;&nbsp;&nbsp;&nbsp;}<br />}<br /><br /></span><span style="color: #0000BB">$obj&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">MethodTest</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$obj</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">runTest</span><span style="color: #007700">(</span><span style="color: #DD0000">'in&nbsp;object&nbsp;context'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">MethodTest</span><span style="color: #007700">::</span><span style="color: #0000BB">runTest</span><span style="color: #007700">(</span><span style="color: #DD0000">'in&nbsp;static&nbsp;context'</span><span style="color: #007700">);&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;As&nbsp;of&nbsp;PHP&nbsp;5.3.0<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

    <div class="example-contents"><p>The above example will output:</p></div>
    <div class="example-contents"><pre>
<div class="cdata"><pre>
Calling object method &#039;runTest&#039; in object context
Calling static method &#039;runTest&#039; in static context
</pre></div>
    </pre></div>
   </div>

  </div>

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