org.arquillian.cube.impl.util.ReflectionUtil Maven / Gradle / Ivy
package org.arquillian.cube.impl.util;
import java.lang.annotation.Annotation;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.ArrayList;
import java.util.List;
/**
* SecurityActions
*
* A set of privileged actions that are not to leak out of this package
*
* @author ALR
* @version $Revision: $
*/
public final class ReflectionUtil {
// -------------------------------------------------------------------------------||
// Constructor
// ------------------------------------------------------------------||
// -------------------------------------------------------------------------------||
/**
* No instantiation
*/
private ReflectionUtil() {
throw new UnsupportedOperationException("No instantiation");
}
// -------------------------------------------------------------------------------||
// Utility Methods
// --------------------------------------------------------------||
// -------------------------------------------------------------------------------||
/**
* Obtains the Thread Context ClassLoader
*/
public static ClassLoader getThreadContextClassLoader() {
return AccessController.doPrivileged(GetTcclAction.INSTANCE);
}
/**
* Obtains the Constructor specified from the given Class and argument types
*
* @param clazz
* @param argumentTypes
* @return
* @throws NoSuchMethodException
*/
public static Constructor getConstructor(final Class clazz,
final Class... argumentTypes) throws NoSuchMethodException {
try {
return AccessController
.doPrivileged(new PrivilegedExceptionAction>() {
public Constructor run()
throws NoSuchMethodException {
return clazz.getConstructor(argumentTypes);
}
});
}
// Unwrap
catch (final PrivilegedActionException pae) {
final Throwable t = pae.getCause();
// Rethrow
if (t instanceof NoSuchMethodException) {
throw (NoSuchMethodException) t;
} else {
// No other checked Exception thrown by Class.getConstructor
try {
throw (RuntimeException) t;
}
// Just in case we've really messed up
catch (final ClassCastException cce) {
throw new RuntimeException(
"Obtained unchecked Exception; this code should never be reached",
t);
}
}
}
}
/**
* Create a new instance by finding a constructor that matches the
* argumentTypes signature using the arguments for instantiation.
*
* @param className
* Full classname of class to create
* @param argumentTypes
* The constructor argument types
* @param arguments
* The constructor arguments
* @return a new instance
* @throws IllegalArgumentException
* if className, argumentTypes, or arguments are null
* @throws RuntimeException
* if any exceptions during creation
* @author Aslak Knutsen
* @author ALR
*/
public static T newInstance(final String className,
final Class[] argumentTypes, final Object[] arguments,
final Class expectedType) {
if (className == null) {
throw new IllegalArgumentException("ClassName must be specified");
}
if (argumentTypes == null) {
throw new IllegalArgumentException(
"ArgumentTypes must be specified. Use empty array if no arguments");
}
if (arguments == null) {
throw new IllegalArgumentException(
"Arguments must be specified. Use empty array if no arguments");
}
final Object obj;
try {
final ClassLoader tccl = getThreadContextClassLoader();
final Class implClass = Class.forName(className, false, tccl);
Constructor constructor = getConstructor(implClass,
argumentTypes);
obj = constructor.newInstance(arguments);
} catch (Exception e) {
throw new RuntimeException("Could not create new instance of "
+ className + ", missing package from classpath?", e);
}
// Cast
try {
return expectedType.cast(obj);
} catch (final ClassCastException cce) {
// Reconstruct so we get some useful information
throw new ClassCastException("Incorrect expected type, "
+ expectedType.getName() + ", defined for "
+ obj.getClass().getName());
}
}
public static boolean isClassPresent(String name) {
try {
ClassLoader classLoader = getThreadContextClassLoader();
classLoader.loadClass(name);
return true;
} catch (ClassNotFoundException e) {
return false;
}
}
public static List getFieldsWithAnnotation(final Class source,
final Class annotationClass) {
List declaredAccessableFields = AccessController
.doPrivileged(new PrivilegedAction>() {
public List run() {
List foundFields = new ArrayList();
Class nextSource = source;
while (nextSource != Object.class) {
for (Field field : nextSource.getDeclaredFields()) {
if (field.isAnnotationPresent(annotationClass)) {
if (!field.isAccessible()) {
field.setAccessible(true);
}
foundFields.add(field);
}
}
nextSource = nextSource.getSuperclass();
}
return foundFields;
}
});
return declaredAccessableFields;
}
public static List getMethodsWithAnnotation(final Class source,
final Class annotationClass) {
List declaredAccessableMethods = AccessController
.doPrivileged(new PrivilegedAction>() {
public List run() {
List foundMethods = new ArrayList();
for (Method method : source.getDeclaredMethods()) {
if (method.isAnnotationPresent(annotationClass)) {
if (!method.isAccessible()) {
method.setAccessible(true);
}
foundMethods.add(method);
}
}
return foundMethods;
}
});
return declaredAccessableMethods;
}
// -------------------------------------------------------------------------------||
// Inner Classes
// ----------------------------------------------------------------||
// -------------------------------------------------------------------------------||
/**
* Single instance to get the TCCL
*/
private enum GetTcclAction implements PrivilegedAction {
INSTANCE;
public ClassLoader run() {
return Thread.currentThread().getContextClassLoader();
}
}
}
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