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* Copyright 2000 - 2008, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.cache.util.reflect;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jboss.cache.CacheException;
import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
/**
* Basic reflection utilities to enhance what the JDK provides.
*
* @author Manik Surtani (<a href="mailto:manik AT jboss DOT org">manik AT jboss DOT org</a>)
* @since 2.1.0
*/
public class ReflectionUtil
{
private static final Log log = LogFactory.getLog(ReflectionUtil.class);
/**
* Returns a set of Methods that contain the given method annotation. This includes all public, protected, package and private
* methods, as well as those of superclasses. Note that this does *not* include overridden methods.
*
* @param c class to inspect
* @param annotationType the type of annotation to look for
* @return List of Method objects that require injection.
*/
public static List<Method> getAllMethods(Class c, Class<? extends Annotation> annotationType)
{
List<Method> annotated = new LinkedList<Method>();
inspectRecursively(c, annotated, annotationType);
return annotated;
}
/**
* Inspects a class and its superclasses (all the way to {@link Object} for method instances that contain a given annotation.
* This even identifies private, package and protected methods, not just public ones.
*
* @param c
* @param s
* @param annotationType
*/
private static void inspectRecursively(Class c, List<Method> s, Class<? extends Annotation> annotationType)
{
// Superclass first
if (!c.equals(Object.class)) inspectRecursively(c.getSuperclass(), s, annotationType);
for (Method m : c.getDeclaredMethods())
{
// don't bother if this method has already been overridden by a subclass
if (!alreadyFound(m, s) && m.isAnnotationPresent(annotationType))
{
s.add(m);
}
}
}
/**
* Tests whether a method has already been found, i.e., overridden.
*
* @param m method to inspect
* @param s collection of methods found
* @return true a method with the same signature already exists.
*/
private static boolean alreadyFound(Method m, Collection<Method> s)
{
for (Method found : s)
{
if (m.getName().equals(found.getName()) &&
Arrays.equals(m.getParameterTypes(), found.getParameterTypes()))
return true;
}
return false;
}
public static void setValue(Object instance, String fieldName, Object value)
{
try
{
Field f = findFieldRecursively(instance.getClass(), fieldName);
if (f == null)
throw new NoSuchMethodException("Cannot find field " + fieldName + " on " + instance.getClass() + " or superclasses");
f.setAccessible(true);
f.set(instance, value);
}
catch (Exception e)
{
log.error("Unable to set value!", e);
}
}
private static Field findFieldRecursively(Class c, String fieldName)
{
Field f = null;
try
{
f = c.getDeclaredField(fieldName);
}
catch (NoSuchFieldException e)
{
if (!c.equals(Object.class)) f = findFieldRecursively(c.getSuperclass(), fieldName);
}
return f;
}
/**
* Invokes a method using reflection, in an accessible manner (by using {@link Method#setAccessible(boolean)}
*
* @param instance instance on which to execute the method
* @param method method to execute
* @param parameters parameters
*/
public static void invokeAccessibly(Object instance, Method method, Object[] parameters)
{
try
{
method.setAccessible(true);
method.invoke(instance, parameters);
}
catch (Exception e)
{
throw new CacheException("Unable to invoke method " + method + " on object " + //instance +
(parameters != null ? " with parameters " + Arrays.asList(parameters) : ""), e);
}
}
}