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<h3>Parent</h3>
<p class="link"><a href="Delegator.html">Delegator</a>
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<h3>Methods</h3>
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<li ><a href="#method-i-__getobj__">#__getobj__</a>
<li ><a href="#method-i-__setobj__">#__setobj__</a>
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<h1 id="class-SimpleDelegator" class="class">
class SimpleDelegator
</h1>
<section class="description">
<p>A concrete implementation of <a href="Delegator.html"><code>Delegator</code></a>, this class provides the means to delegate all supported method calls to the object passed into the constructor and even to change the object being delegated to at a later time with #__setobj__.</p>
<pre class="ruby"><span class="ruby-keyword">class</span> <span class="ruby-constant">User</span>
<span class="ruby-keyword">def</span> <span class="ruby-identifier ruby-title">born_on</span>
<span class="ruby-constant">Date</span>.<span class="ruby-identifier">new</span>(<span class="ruby-value">1989</span>, <span class="ruby-value">9</span>, <span class="ruby-value">10</span>)
<span class="ruby-keyword">end</span>
<span class="ruby-keyword">end</span>
<span class="ruby-keyword">class</span> <span class="ruby-constant">UserDecorator</span> <span class="ruby-operator"><</span> <span class="ruby-constant">SimpleDelegator</span>
<span class="ruby-keyword">def</span> <span class="ruby-identifier ruby-title">birth_year</span>
<span class="ruby-identifier">born_on</span>.<span class="ruby-identifier">year</span>
<span class="ruby-keyword">end</span>
<span class="ruby-keyword">end</span>
<span class="ruby-identifier">decorated_user</span> = <span class="ruby-constant">UserDecorator</span>.<span class="ruby-identifier">new</span>(<span class="ruby-constant">User</span>.<span class="ruby-identifier">new</span>)
<span class="ruby-identifier">decorated_user</span>.<span class="ruby-identifier">birth_year</span> <span class="ruby-comment">#=> 1989</span>
<span class="ruby-identifier">decorated_user</span>.<span class="ruby-identifier">__getobj__</span> <span class="ruby-comment">#=> #<User: ...></span>
</pre>
<p>A <a href="SimpleDelegator.html"><code>SimpleDelegator</code></a> instance can take advantage of the fact that <a href="SimpleDelegator.html"><code>SimpleDelegator</code></a> is a subclass of <code>Delegator</code> to call <code>super</code> to have methods called on the object being delegated to.</p>
<pre class="ruby"><span class="ruby-keyword">class</span> <span class="ruby-constant">SuperArray</span> <span class="ruby-operator"><</span> <span class="ruby-constant">SimpleDelegator</span>
<span class="ruby-keyword">def</span> <span class="ruby-identifier ruby-title">[]</span>(<span class="ruby-operator">*</span><span class="ruby-identifier">args</span>)
<span class="ruby-keyword">super</span> <span class="ruby-operator">+</span> <span class="ruby-value">1</span>
<span class="ruby-keyword">end</span>
<span class="ruby-keyword">end</span>
<span class="ruby-constant">SuperArray</span>.<span class="ruby-identifier">new</span>([<span class="ruby-value">1</span>])[<span class="ruby-value">0</span>] <span class="ruby-comment">#=> 2</span>
</pre>
<p>Here's a simple example that takes advantage of the fact that SimpleDelegator's delegation object can be changed at any time.</p>
<pre class="ruby"><span class="ruby-keyword">class</span> <span class="ruby-constant">Stats</span>
<span class="ruby-keyword">def</span> <span class="ruby-identifier ruby-title">initialize</span>
<span class="ruby-ivar">@source</span> = <span class="ruby-constant">SimpleDelegator</span>.<span class="ruby-identifier">new</span>([])
<span class="ruby-keyword">end</span>
<span class="ruby-keyword">def</span> <span class="ruby-identifier ruby-title">stats</span>(<span class="ruby-identifier">records</span>)
<span class="ruby-ivar">@source</span>.<span class="ruby-identifier">__setobj__</span>(<span class="ruby-identifier">records</span>)
<span class="ruby-node">"Elements: #{@source.size}\n"</span> <span class="ruby-operator">+</span>
<span class="ruby-node">" Non-Nil: #{@source.compact.size}\n"</span> <span class="ruby-operator">+</span>
<span class="ruby-node">" Unique: #{@source.uniq.size}\n"</span>
<span class="ruby-keyword">end</span>
<span class="ruby-keyword">end</span>
<span class="ruby-identifier">s</span> = <span class="ruby-constant">Stats</span>.<span class="ruby-identifier">new</span>
<span class="ruby-identifier">puts</span> <span class="ruby-identifier">s</span>.<span class="ruby-identifier">stats</span>(<span class="ruby-node">%w{James Edward Gray II}</span>)
<span class="ruby-identifier">puts</span>
<span class="ruby-identifier">puts</span> <span class="ruby-identifier">s</span>.<span class="ruby-identifier">stats</span>([<span class="ruby-value">1</span>, <span class="ruby-value">2</span>, <span class="ruby-value">3</span>, <span class="ruby-keyword">nil</span>, <span class="ruby-value">4</span>, <span class="ruby-value">5</span>, <span class="ruby-value">1</span>, <span class="ruby-value">2</span>])
</pre>
<p>Prints:</p>
<pre>Elements: 4
Non-Nil: 4
Unique: 4
Elements: 8
Non-Nil: 7
Unique: 6</pre>
</section>
<section id="5Buntitled-5D" class="documentation-section">
<section id="public-instance-5Buntitled-5D-method-details" class="method-section">
<header>
<h3>Public Instance Methods</h3>
</header>
<div id="method-i-__getobj__" class="method-detail ">
<div class="method-heading">
<span class="method-name">__getobj__</span><span
class="method-args">() { || ... }</span>
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<div class="method-description">
<p>Returns the current object method calls are being delegated to.</p>
<div class="method-source-code" id="__getobj__-source">
<pre><span class="ruby-comment"># File lib/delegate.rb, line 312</span>
<span class="ruby-keyword">def</span> <span class="ruby-identifier ruby-title">__getobj__</span>
<span class="ruby-keyword">unless</span> <span class="ruby-keyword">defined?</span>(<span class="ruby-ivar">@delegate_sd_obj</span>)
<span class="ruby-keyword">return</span> <span class="ruby-keyword">yield</span> <span class="ruby-keyword">if</span> <span class="ruby-identifier">block_given?</span>
<span class="ruby-identifier">__raise__</span> <span class="ruby-operator">::</span><span class="ruby-constant">ArgumentError</span>, <span class="ruby-string">"not delegated"</span>
<span class="ruby-keyword">end</span>
<span class="ruby-ivar">@delegate_sd_obj</span>
<span class="ruby-keyword">end</span></pre>
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<div id="method-i-__setobj__" class="method-detail ">
<div class="method-heading">
<span class="method-name">__setobj__</span><span
class="method-args">(obj)</span>
<span class="method-click-advice">click to toggle source</span>
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<div class="method-description">
<p>Changes the delegate object to <em>obj</em>.</p>
<p>It's important to note that this does <strong>not</strong> cause SimpleDelegator's methods to change. Because of this, you probably only want to change delegation to objects of the same type as the original delegate.</p>
<p>Here's an example of changing the delegation object.</p>
<pre class="ruby"><span class="ruby-identifier">names</span> = <span class="ruby-constant">SimpleDelegator</span>.<span class="ruby-identifier">new</span>(<span class="ruby-node">%w{James Edward Gray II}</span>)
<span class="ruby-identifier">puts</span> <span class="ruby-identifier">names</span>[<span class="ruby-value">1</span>] <span class="ruby-comment"># => Edward</span>
<span class="ruby-identifier">names</span>.<span class="ruby-identifier">__setobj__</span>(<span class="ruby-node">%w{Gavin Sinclair}</span>)
<span class="ruby-identifier">puts</span> <span class="ruby-identifier">names</span>[<span class="ruby-value">1</span>] <span class="ruby-comment"># => Sinclair</span>
</pre>
<div class="method-source-code" id="__setobj__-source">
<pre><span class="ruby-comment"># File lib/delegate.rb, line 334</span>
<span class="ruby-keyword">def</span> <span class="ruby-identifier ruby-title">__setobj__</span>(<span class="ruby-identifier">obj</span>)
<span class="ruby-identifier">__raise__</span> <span class="ruby-operator">::</span><span class="ruby-constant">ArgumentError</span>, <span class="ruby-string">"cannot delegate to self"</span> <span class="ruby-keyword">if</span> <span class="ruby-keyword">self</span>.<span class="ruby-identifier">equal?</span>(<span class="ruby-identifier">obj</span>)
<span class="ruby-ivar">@delegate_sd_obj</span> = <span class="ruby-identifier">obj</span>
<span class="ruby-keyword">end</span></pre>
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