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12.5.2 pre_randomize()与post_randomize()</div>
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每一个类都包含了内建的<span style="color: #0000FF">pre_randomize</span><span style="color: #800080">()</span>和<span style="color: #0000FF">post_randomize</span><span style="color: #800080">()</span>函数，它们在计算新的随机值之前和之后被 <span style="color: #0000FF">randomize</span><span style="color: #800080">()</span>自动调用。 </p>
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<span style="color: #0000FF">pre_randomize</span><span style="color: #800080">()</span>的内建定义如下： </p><div class="Element170">
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<div class="Element13"><div class="Element12" id="code00440"><pre class="Element12"><span style="color: #0000FF">function void</span> pre_randomize<span style="color: #800080">;</span>
<span style="color: #0000FF">if</span> <span style="color: #800080">(</span><span style="color: #0000FF">super</span><span style="color: #800080">)</span> <span style="color: #0000FF">super</span><span style="color: #800080">.</span>pre_randomize<span style="color: #800080">();</span> <span style="color: #008000">// 检测super以便确定对象句柄是否存在</span>
<span style="color: #008000"> // 可选的在随机化之前的编程从这里开始</span>
<span style="color: #0000FF">endfunction</span></pre></div></div>
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<span style="color: #0000FF">post_randomize</span><span style="color: #800080">()</span>的内建定义如下： </p><div class="Element170">
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<div class="Element13"><div class="Element12" id="code00441"><pre class="Element12"><span style="color: #0000FF">function void</span> post_randomize<span style="color: #800080">;</span>
<span style="color: #0000FF">if</span> <span style="color: #800080">(</span><span style="color: #0000FF">super</span><span style="color: #800080">)</span> <span style="color: #0000FF">super</span><span style="color: #800080">.</span>post_randomize<span style="color: #800080">();</span> <span style="color: #008000">// 检测super以便确定对象句柄是否存在</span>
<span style="color: #008000">//可选的在随机化之后的编程从这里开始</span>
<span style="color: #0000FF">endfunction</span></pre></div></div>
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当调用<i>obj<span style="color: #800080"></i>.</span><span style="color: #0000FF">randomize</span><span style="color: #800080">()</span>的时候，它首先调用<i>obj</i>的<span style="color: #0000FF">pre_randomize</span><span style="color: #800080">()</span>方法以及它的所有被使能的随机对象成员。接下来<span style="color: #0000FF">pre_randomize</span><span style="color: #800080">()</span>会调用<span style="color: #0000FF">super</span><span style="color: #800080">.</span><span style="color: #0000FF">pre_randomize</span><span style="color: #800080">()</span>。在新的随机值被计算并赋值后，<span style="color: #0000FF">randomize</span><span style="color: #800080">()</span>会调用<i>obj</i>的<span style="color: #0000FF">post_randomize</span><span style="color: #800080">()</span>方法以及它的所有被使能的随机对象成员。接下来<span style="color: #0000FF">post_randomize</span><span style="color: #800080">()</span>会调用<span style="color: #0000FF">super</span><span style="color: #800080">.</span><span style="color: #0000FF">post_randomize</span><span style="color: #800080">()</span>。 </p>
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用户可以在任何类中过载<span style="color: #0000FF">pre_randomize</span><span style="color: #800080">()</span>方法以便执行对象被随机化之前的初始化和预处理。 </p>
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用户可以在任何类中过载<span style="color: #0000FF">post_randomize</span><span style="color: #800080">()</span>方法以便执行对象被随机化之后的清除、打印诊断、以及后处理。 </p>
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如果这些方法被过载，那么它们必须调用对应的父类方法，否则它们在随机化之前和之后的处理步骤会被忽略。 </p>
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<span style="color: #0000FF">pre_randomize</span><span style="color: #800080">()</span>和<span style="color: #0000FF">post_randomize</span><span style="color: #800080">()</span>方法不是虚拟的。然而，因为它们会被虚拟的<span style="color: #0000FF">randomize</span><span style="color: #800080">()</span>方法自动调用，所以它们看上去像是虚拟的。 </p></div>
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