org.springframework.aop.aspectj.annotation.AbstractAspectJAdvisorFactory Maven / Gradle / Ivy
/*
* Copyright 2002-2018 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.aspectj.annotation;
import java.lang.annotation.Annotation;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.HashMap;
import java.util.Map;
import java.util.StringTokenizer;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.AfterThrowing;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.aspectj.lang.reflect.AjType;
import org.aspectj.lang.reflect.AjTypeSystem;
import org.aspectj.lang.reflect.PerClauseKind;
import org.springframework.aop.framework.AopConfigException;
import org.springframework.core.ParameterNameDiscoverer;
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.lang.Nullable;
/**
* Abstract base class for factories that can create Spring AOP Advisors
* given AspectJ classes from classes honoring the AspectJ 5 annotation syntax.
*
* This class handles annotation parsing and validation functionality.
* It does not actually generate Spring AOP Advisors, which is deferred to subclasses.
*
* @author Rod Johnson
* @author Adrian Colyer
* @author Juergen Hoeller
* @since 2.0
*/
public abstract class AbstractAspectJAdvisorFactory implements AspectJAdvisorFactory {
private static final String AJC_MAGIC = "ajc$";
private static final Class[] ASPECTJ_ANNOTATION_CLASSES = new Class[] {
Pointcut.class, Around.class, Before.class, After.class, AfterReturning.class, AfterThrowing.class};
/** Logger available to subclasses. */
protected final Log logger = LogFactory.getLog(getClass());
protected final ParameterNameDiscoverer parameterNameDiscoverer = new AspectJAnnotationParameterNameDiscoverer();
/**
* We consider something to be an AspectJ aspect suitable for use by the Spring AOP system
* if it has the @Aspect annotation, and was not compiled by ajc. The reason for this latter test
* is that aspects written in the code-style (AspectJ language) also have the annotation present
* when compiled by ajc with the -1.5 flag, yet they cannot be consumed by Spring AOP.
*/
@Override
public boolean isAspect(Class clazz) {
return (hasAspectAnnotation(clazz) && !compiledByAjc(clazz));
}
private boolean hasAspectAnnotation(Class clazz) {
return (AnnotationUtils.findAnnotation(clazz, Aspect.class) != null);
}
/**
* We need to detect this as "code-style" AspectJ aspects should not be
* interpreted by Spring AOP.
*/
private boolean compiledByAjc(Class clazz) {
// The AJTypeSystem goes to great lengths to provide a uniform appearance between code-style and
// annotation-style aspects. Therefore there is no 'clean' way to tell them apart. Here we rely on
// an implementation detail of the AspectJ compiler.
for (Field field : clazz.getDeclaredFields()) {
if (field.getName().startsWith(AJC_MAGIC)) {
return true;
}
}
return false;
}
@Override
public void validate(Class aspectClass) throws AopConfigException {
// If the parent has the annotation and isn't abstract it's an error
if (aspectClass.getSuperclass().getAnnotation(Aspect.class) != null &&
!Modifier.isAbstract(aspectClass.getSuperclass().getModifiers())) {
throw new AopConfigException("[" + aspectClass.getName() + "] cannot extend concrete aspect [" +
aspectClass.getSuperclass().getName() + "]");
}
AjType ajType = AjTypeSystem.getAjType(aspectClass);
if (!ajType.isAspect()) {
throw new NotAnAtAspectException(aspectClass);
}
if (ajType.getPerClause().getKind() == PerClauseKind.PERCFLOW) {
throw new AopConfigException(aspectClass.getName() + " uses percflow instantiation model: " +
"This is not supported in Spring AOP.");
}
if (ajType.getPerClause().getKind() == PerClauseKind.PERCFLOWBELOW) {
throw new AopConfigException(aspectClass.getName() + " uses percflowbelow instantiation model: " +
"This is not supported in Spring AOP.");
}
}
/**
* Find and return the first AspectJ annotation on the given method
* (there should only be one anyway...).
*/
@SuppressWarnings("unchecked")
@Nullable
protected static AspectJAnnotation findAspectJAnnotationOnMethod(Method method) {
for (Class clazz : ASPECTJ_ANNOTATION_CLASSES) {
AspectJAnnotation foundAnnotation = findAnnotation(method, (Class) clazz);
if (foundAnnotation != null) {
return foundAnnotation;
}
}
return null;
}
@Nullable
private static AspectJAnnotation findAnnotation(Method method, Class toLookFor) {
A result = AnnotationUtils.findAnnotation(method, toLookFor);
if (result != null) {
return new AspectJAnnotation<>(result);
}
else {
return null;
}
}
/**
* Enum for AspectJ annotation types.
* @see AspectJAnnotation#getAnnotationType()
*/
protected enum AspectJAnnotationType {
AtPointcut, AtAround, AtBefore, AtAfter, AtAfterReturning, AtAfterThrowing
}
/**
* Class modelling an AspectJ annotation, exposing its type enumeration and
* pointcut String.
* @param the annotation type
*/
protected static class AspectJAnnotation {
private static final String[] EXPRESSION_ATTRIBUTES = new String[] {"pointcut", "value"};
private static Map, AspectJAnnotationType> annotationTypeMap = new HashMap<>(8);
static {
annotationTypeMap.put(Pointcut.class, AspectJAnnotationType.AtPointcut);
annotationTypeMap.put(Around.class, AspectJAnnotationType.AtAround);
annotationTypeMap.put(Before.class, AspectJAnnotationType.AtBefore);
annotationTypeMap.put(After.class, AspectJAnnotationType.AtAfter);
annotationTypeMap.put(AfterReturning.class, AspectJAnnotationType.AtAfterReturning);
annotationTypeMap.put(AfterThrowing.class, AspectJAnnotationType.AtAfterThrowing);
}
private final A annotation;
private final AspectJAnnotationType annotationType;
private final String pointcutExpression;
private final String argumentNames;
public AspectJAnnotation(A annotation) {
this.annotation = annotation;
this.annotationType = determineAnnotationType(annotation);
try {
this.pointcutExpression = resolveExpression(annotation);
Object argNames = AnnotationUtils.getValue(annotation, "argNames");
this.argumentNames = (argNames instanceof String ? (String) argNames : "");
}
catch (Exception ex) {
throw new IllegalArgumentException(annotation + " is not a valid AspectJ annotation", ex);
}
}
private AspectJAnnotationType determineAnnotationType(A annotation) {
AspectJAnnotationType type = annotationTypeMap.get(annotation.annotationType());
if (type != null) {
return type;
}
throw new IllegalStateException("Unknown annotation type: " + annotation);
}
private String resolveExpression(A annotation) {
for (String attributeName : EXPRESSION_ATTRIBUTES) {
Object val = AnnotationUtils.getValue(annotation, attributeName);
if (val instanceof String) {
String str = (String) val;
if (!str.isEmpty()) {
return str;
}
}
}
throw new IllegalStateException("Failed to resolve expression: " + annotation);
}
public AspectJAnnotationType getAnnotationType() {
return this.annotationType;
}
public A getAnnotation() {
return this.annotation;
}
public String getPointcutExpression() {
return this.pointcutExpression;
}
public String getArgumentNames() {
return this.argumentNames;
}
@Override
public String toString() {
return this.annotation.toString();
}
}
/**
* ParameterNameDiscoverer implementation that analyzes the arg names
* specified at the AspectJ annotation level.
*/
private static class AspectJAnnotationParameterNameDiscoverer implements ParameterNameDiscoverer {
@Override
@Nullable
public String[] getParameterNames(Method method) {
if (method.getParameterCount() == 0) {
return new String[0];
}
AspectJAnnotation annotation = findAspectJAnnotationOnMethod(method);
if (annotation == null) {
return null;
}
StringTokenizer nameTokens = new StringTokenizer(annotation.getArgumentNames(), ",");
if (nameTokens.countTokens() > 0) {
String[] names = new String[nameTokens.countTokens()];
for (int i = 0; i < names.length; i++) {
names[i] = nameTokens.nextToken();
}
return names;
}
else {
return null;
}
}
@Override
@Nullable
public String[] getParameterNames(Constructor ctor) {
throw new UnsupportedOperationException("Spring AOP cannot handle constructor advice");
}
}
}