Get Annotation Parameter
// $Id: ReflectionHelper.java 16271 2009-04-07 20:20:12Z hardy.ferentschik $
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* Licensed under the Apache License, Version 2.0 (the "License");
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import java.beans.Introspector;
import java.lang.annotation.Annotation;
import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.lang.reflect.WildcardType;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
/**
* Some reflection utility methods.
*
* @author Hardy Ferentschik
*/
public class ReflectionHelper {
@SuppressWarnings("unchecked")
public static <T> T getAnnotationParameter(Annotation annotation, String parameterName, Class<T> type) {
try {
Method m = annotation.getClass().getMethod( parameterName );
Object o = m.invoke( annotation );
if ( o.getClass().getName().equals( type.getName() ) ) {
return ( T ) o;
}
else {
String msg = "Wrong parameter type. Expected: " + type.getName() + " Actual: " + o.getClass().getName();
throw new RuntimeException( msg );
}
}
catch ( NoSuchMethodException e ) {
String msg = "The specified annotation defines no parameter '" + parameterName + "'.";
throw new RuntimeException( msg, e );
}
catch ( IllegalAccessException e ) {
String msg = "Unable to get '" + parameterName + "' from " + annotation.getClass().getName();
throw new RuntimeException( msg, e );
}
catch ( InvocationTargetException e ) {
String msg = "Unable to get '" + parameterName + "' from " + annotation.getClass().getName();
throw new RuntimeException( msg, e );
}
}
}