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POEfficient Java Annotations
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copied!<p>I'm a huge fan of Java's annotations, but find it a pain in the neck to have to include Google's <a href="https://code.google.com/p/reflections/" rel="nofollow">Reflections</a> or <a href="http://scannotation.sourceforge.net/" rel="nofollow">Scannotations</a> every time I want to make my own.</p> <p>I haven't been able to find any documentation about Java being able to automatically scan for annotations & use them appropriately, without the help of a container or alike.</p> <p><strong>Question:</strong> Have I missed something fundamental about Java, or were annotations always designed such that manual scanning & checking is required? Is there some built-in way of handling annotations?</p> <p><em>To clarify further</em></p> <p>I'd like to be able to approach annotations in Java a little more programatically. For instance, say you wanted to build a <code>List</code> of <code>Car</code>s. To do this, you annotate the list with a class that can populate the list for you. For instance:</p> <pre><code>@CarMaker List<Car> cars = new List<Car>(); </code></pre> <p>In this example, the <code>CarMaker</code> annotation is approached by Java, who strikes a deal and asks them how many cars they want to provide. It's up to the <code>CarMaker</code> annotation/class to then provide them with a list of which cars to include. This could be all classes with <code>@CarType</code> annotations, and a <code>Car</code> interface.</p> <p><em>Another way of looking at it</em>, is that if you know you want to build something like this: <code>List<Car> cars</code>, you could annotate it with <code>@ListMaker<Car></code>. The <code>ListMaker</code> is something built into Java. It looks for all classes annotated with <code>@CarType</code>, and populates the list accordingly.</p>

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