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<h3>Using the Annotations reader class</h3>

<p>You can retrieve the backport175 annotations as well as regular Java 5 annotations (when running Java 5) at runtime using the API in the <code>Annotations</code> class.</p>

<p>You retreive the annotations by specifying the:</p>

<ul>
	<li>name of the annotations - this must be the fully qualified name of the annotation interface.</li>
	<li>class or member that is annotated - this is the <code>java.lang.Class</code> (for class level annotations) or one of the member class in the <code>java.lang.reflect.*</code> package for member level annotations (methods, fields and constructors)</li>
</ul>

<p>Here is a sample part of the API:</p>

<table class="wysiwyg-macro" data-macro-name="code" data-macro-default-parameter="java" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e2NvZGU6amF2YX0&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>
// class annotations
public static boolean isAnnotationPresent(Class annotation, Class klass)
public static Annotation getAnnotation(Class annotation, Class klass)
public static Annotation[] getAnnotations(Class klass)

// method annotations
public static boolean isAnnotationPresent(Class annotation, Method method)
public static Annotation getAnnotation(Class annotation, Method method)
public static Annotation[] getAnnotations(Method method)

...
</pre></td></tr></table>

<h3>The Annotation interface</h3>

<p>All these methods in the <code>Annotations</code> reader class return an instance of the type <code>org.codehaus.backport175.reader.Annotation</code>. </p>

<p>This class has some useful methods like:</p>

<table class="wysiwyg-macro" data-macro-name="code" data-macro-default-parameter="java" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e2NvZGU6amF2YX0&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>
/**
 * Returns the annotation type, e.g. the annotation interface type.
 *
 * @return the type
 */
Class annotationType();

/**
 * Returns a string representation that is identical to the annotation 
 * that was parsed by the compiler.
 *
 * @return the string representation
 */
String toString();
</pre></td></tr></table>

<p>But most likely you want to cast the instance to the correct annotation type (interface). </p>

<h3>Example</h3>

<p>Here is an example on how to read in the EJB 3 transaction annotation:</p>

<table class="wysiwyg-macro" data-macro-name="code" data-macro-default-parameter="java" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e2NvZGU6amF2YX0&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>
if (Annotations.isAnnotationPresent(javax.ejb.TransactionAttribute.class, method)) {

Annotation annotation = Annotations.getAnnotation(javax.ejb.TransactionAttribute.class, method);

javax.ejb.TransactionAttribute txAttribute = (javax.ejb.TransactionAttribute)annotation;
}
</pre></td></tr></table>

<h3>Notes</h3>

<p>If an annotation has an element with a default value, the reflective API will off course gives you access to it if the<br />
annotated class/member was not specifying it.</p>