org.springframework.webflow.util.ReflectionUtils Maven / Gradle / Ivy
/*
* Copyright 2004-2007 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.webflow.util;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
/**
* Simple utility class for working with the java reflection API. Only intended for internal use. Will likely disappear
* in a future release of Spring Web Flow and simply rely on {@link org.springframework.util.ReflectionUtils} if
* necessary.
*
* @author Keith Donald
*/
public class ReflectionUtils {
/**
* Invoke the specified {@link Method} against the supplied target object with no arguments. The target object can
* be null when invoking a static {@link Method}. All exceptions are treated as fatal and will be
* converted to unchecked exceptions.
* @see #invokeMethod(java.lang.reflect.Method, Object, Object[])
* @throws RuntimeException when something goes wrong invoking the method or when the method itself throws an
* exception
*/
public static Object invokeMethod(Method method, Object target) throws RuntimeException {
return invokeMethod(method, target, null);
}
/**
* Invoke the specified {@link Method} against the supplied target object with the supplied arguments. The target
* object can be null when invoking a static {@link Method}. All exceptions are treated as fatal and will be
* converted to unchecked exceptions.
* @see #invokeMethod(java.lang.reflect.Method, Object, Object[])
* @throws RuntimeException when something goes wrong invoking the method or when the method itself throws an
* exception
*/
public static Object invokeMethod(Method method, Object target, Object[] args) throws RuntimeException {
try {
return method.invoke(target, args);
} catch (IllegalAccessException ex) {
handleReflectionException(ex);
throw new IllegalStateException("Unexpected reflection exception - " + ex.getClass().getName() + ": "
+ ex.getMessage());
} catch (InvocationTargetException ex) {
handleReflectionException(ex);
throw new IllegalStateException("Unexpected reflection exception - " + ex.getClass().getName() + ": "
+ ex.getMessage());
}
}
/**
* Handle the given reflection exception. Should only be called if no checked exception is expected to be thrown by
* the target method.
*
* Throws the underlying RuntimeException or Error in case of an InvocationTargetException with such a root cause.
* Throws an IllegalStateException with an appropriate message else.
* @param ex the reflection exception to handle
*/
private static void handleReflectionException(Exception ex) {
if (ex instanceof NoSuchMethodException) {
throw new IllegalStateException("Method not found: " + ex.getMessage());
}
if (ex instanceof IllegalAccessException) {
throw new IllegalStateException("Could not access method: " + ex.getMessage());
}
if (ex instanceof InvocationTargetException) {
handleInvocationTargetException((InvocationTargetException) ex);
}
throw new IllegalStateException("Unexpected reflection exception - " + ex.getClass().getName() + ": "
+ ex.getMessage());
}
/**
* Handle the given invocation target exception. Should only be called if no checked exception is expected to be
* thrown by the target method.
*
* Throws the underlying RuntimeException or Error in case of such a root cause. Throws an IllegalStateException
* else.
* @param ex the invocation target exception to handle
*/
private static void handleInvocationTargetException(InvocationTargetException ex) {
if (ex.getTargetException() instanceof RuntimeException) {
throw (RuntimeException) ex.getTargetException();
}
if (ex.getTargetException() instanceof Error) {
throw (Error) ex.getTargetException();
}
throw new IllegalStateException("Unexpected exception thrown by method - "
+ ex.getTargetException().getClass().getName() + ": " + ex.getTargetException().getMessage());
}
}