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POElegant way of specifying either objects or enums as a parameter
 

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    <p>I've made the following code to turn an <code>ArrayList</code> (say values <code>"Cat", "Dog", "Fish"</code>) into a human-readable string (say <code>"Cat,Dog,Fish"</code>), which is a simple task but I want to extend it elegantly. What I've got so far is:</p> <pre><code>public static String makeStringList(Iterable&lt;String&gt; items) { StringBuilder sb = new StringBuilder(); for (String item : items) { sb.append(item); sb.append(","); } if (sb.length() &gt; 0) { sb.deleteCharAt(sb.length() - 1); } return sb.toString(); } </code></pre> <p>But I have another object which is an <code>ArrayList</code> of <code>Enum</code> values, say:</p> <pre><code>enum Animal { cat("Cat"), dog("Dog"), fish("Fish"); String value; Animal(String num) { value = num; } } </code></pre> <p>And an <code>ArrayList&lt;Animal&gt;</code> containing <code>(Animal.cat, Animal.dog, Animal.fish)</code>.</p> <p>What's the best way to extend my <code>makeStringList</code> function so that it accepts <code>ArrayList</code>s of either <code>Enum</code>s or <code>String</code>s? I've tried changing the parameter to <code>Iterable&lt;Object&gt; items</code> and using <code>toString()</code> but apparently my enums don't extend <code>Object</code> so there's no <code>toString()</code>. I've also tried creating an interface <code>hasStringRepresentation</code> with a function <code>getStringRepresentation</code>, which works great but won't work for strings.</p> <p>Is there an elegant way I can extend the makeStringList function to accept either Objects or Enums? The obvious answer is overloading makeStringList but I'd like to limit the question to answers which don't involve overloading.</p>
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    1. USMatt Lyons
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