org.springframework.aop.framework.adapter.ThrowsAdviceInterceptor Maven / Gradle / Ivy
/*
* Copyright 2002-2020 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
*
* https://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.aop.framework.adapter;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.aop.AfterAdvice;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
/**
* Interceptor to wrap an after-throwing advice.
*
* The signatures on handler methods on the {@code ThrowsAdvice}
* implementation method argument must be of the form:
*
* {@code void afterThrowing([Method, args, target], ThrowableSubclass);}
*
*
Only the last argument is required.
*
*
Some examples of valid methods would be:
*
*
public void afterThrowing(Exception ex)
* public void afterThrowing(RemoteException)
* public void afterThrowing(Method method, Object[] args, Object target, Exception ex)
* public void afterThrowing(Method method, Object[] args, Object target, ServletException ex)
*
* This is a framework class that need not be used directly by Spring users.
*
* @author Rod Johnson
* @author Juergen Hoeller
* @see MethodBeforeAdviceInterceptor
* @see AfterReturningAdviceInterceptor
*/
public class ThrowsAdviceInterceptor implements MethodInterceptor, AfterAdvice {
private static final String AFTER_THROWING = "afterThrowing";
private static final Log logger = LogFactory.getLog(ThrowsAdviceInterceptor.class);
private final Object throwsAdvice;
/** Methods on throws advice, keyed by exception class. */
private final Map, Method> exceptionHandlerMap = new HashMap<>();
/**
* Create a new ThrowsAdviceInterceptor for the given ThrowsAdvice.
* @param throwsAdvice the advice object that defines the exception handler methods
* (usually a {@link org.springframework.aop.ThrowsAdvice} implementation)
*/
public ThrowsAdviceInterceptor(Object throwsAdvice) {
Assert.notNull(throwsAdvice, "Advice must not be null");
this.throwsAdvice = throwsAdvice;
Method[] methods = throwsAdvice.getClass().getMethods();
for (Method method : methods) {
if (method.getName().equals(AFTER_THROWING) &&
(method.getParameterCount() == 1 || method.getParameterCount() == 4)) {
Class throwableParam = method.getParameterTypes()[method.getParameterCount() - 1];
if (Throwable.class.isAssignableFrom(throwableParam)) {
// An exception handler to register...
this.exceptionHandlerMap.put(throwableParam, method);
if (logger.isDebugEnabled()) {
logger.debug("Found exception handler method on throws advice: " + method);
}
}
}
}
if (this.exceptionHandlerMap.isEmpty()) {
throw new IllegalArgumentException(
"At least one handler method must be found in class [" + throwsAdvice.getClass() + "]");
}
}
/**
* Return the number of handler methods in this advice.
*/
public int getHandlerMethodCount() {
return this.exceptionHandlerMap.size();
}
@Override
@Nullable
public Object invoke(MethodInvocation mi) throws Throwable {
try {
return mi.proceed();
}
catch (Throwable ex) {
Method handlerMethod = getExceptionHandler(ex);
if (handlerMethod != null) {
invokeHandlerMethod(mi, ex, handlerMethod);
}
throw ex;
}
}
/**
* Determine the exception handle method for the given exception.
* @param exception the exception thrown
* @return a handler for the given exception type, or {@code null} if none found
*/
@Nullable
private Method getExceptionHandler(Throwable exception) {
Class exceptionClass = exception.getClass();
if (logger.isTraceEnabled()) {
logger.trace("Trying to find handler for exception of type [" + exceptionClass.getName() + "]");
}
Method handler = this.exceptionHandlerMap.get(exceptionClass);
while (handler == null && exceptionClass != Throwable.class) {
exceptionClass = exceptionClass.getSuperclass();
handler = this.exceptionHandlerMap.get(exceptionClass);
}
if (handler != null && logger.isTraceEnabled()) {
logger.trace("Found handler for exception of type [" + exceptionClass.getName() + "]: " + handler);
}
return handler;
}
private void invokeHandlerMethod(MethodInvocation mi, Throwable ex, Method method) throws Throwable {
Object[] handlerArgs;
if (method.getParameterCount() == 1) {
handlerArgs = new Object[] {ex};
}
else {
handlerArgs = new Object[] {mi.getMethod(), mi.getArguments(), mi.getThis(), ex};
}
try {
method.invoke(this.throwsAdvice, handlerArgs);
}
catch (InvocationTargetException targetEx) {
throw targetEx.getTargetException();
}
}
}