laravel連接多個不同數據庫的單例類

<code class="sourceCode php"><span class="kw">class</span> singletonInstance 
{

    <span class="kw">protected</span> <span class="kw">static</span> <span class="kw">$instances</span> = <span class="ot">[];</span>
    <span class="kw">protected</span> <span class="kw">static</span> <span class="kw">$table</span> = <span class="kw">null</span><span class="ot">;</span>
    <span class="kw">protected</span> <span class="kw">static</span> <span class="kw">$connection</span> = <span class="kw">null</span><span class="ot">;</span>

    <span class="kw">public</span> <span class="kw">function</span> <span class="fu">__construct</span><span class="ot">()</span>
    {
        <span class="kw">if</span><span class="ot">(</span>!<span class="fu">isset</span><span class="ot">(</span><span class="kw">static</span>::<span class="kw">$instances</span><span class="ot">[</span><span class="kw">static</span>::<span class="kw">class</span><span class="ot">]))</span>{
            <span class="kw">if</span><span class="ot">(</span><span class="fu">is_null</span><span class="ot">(</span><span class="kw">self</span>::<span class="kw">$table</span><span class="ot">)</span> || <span class="fu">is_null</span><span class="ot">(</span><span class="kw">self</span>::<span class="kw">$connection</span><span class="ot">))</span>
            {
                <span class="kw">throw</span> <span class="kw">new</span> \<span class="kw">Exception</span><span class="ot">(</span><span class="st">'not defined property'</span><span class="ot">);</span>
            }
            <span class="kw">static</span>::<span class="kw">$instances</span><span class="ot">[</span><span class="kw">static</span>::<span class="kw">class</span><span class="ot">]</span> = <span class="kw">DB</span>::connection<span class="ot">(</span><span class="kw">self</span>::connection<span class="ot">)</span>->table<span class="ot">(</span><span class="kw">self</span>::<span class="kw">$table</span><span class="ot">);</span>
        }
    }

    <span class="kw">public</span> <span class="kw">static</span> <span class="kw">function</span> getDB<span class="ot">()</span>
    {
        <span class="kw">return</span> <span class="kw">static</span>::<span class="kw">$instances</span><span class="ot">[</span><span class="kw">static</span>::<span class="kw">class</span><span class="ot">];</span>
    }

}</code>