/**************************************************************************************
* Copyright (c) Jonas Bon�r, Alexandre Vasseur. All rights reserved. *
* http://aspectwerkz.codehaus.org *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the QPL license *
* a copy of which has been included with this distribution in the license.txt file. *
**************************************************************************************/
package org.codehaus.aspectwerkz.attribdef.definition.attribute;
import java.lang.reflect.Method;
import java.lang.reflect.Field;
import java.util.Map;
import java.util.HashMap;
import java.util.ArrayList;
import java.util.Arrays;
import org.codehaus.aspectwerkz.attribdef.definition.attribute.bcel.BcelAttributeExtractor;
import org.codehaus.aspectwerkz.exception.WrappedRuntimeException;
/**
* Retrieves attributes on class, method and field level
*
* Based on code from the Attrib4j project by Mark Pollack and Ted Neward (http://attrib4j.sourceforge.net/).
*
* @author <a href="mailto:jboner@codehaus.org">Jonas Bon�r</a>
*/
public class Attributes {
/**
* Hold a cache of AttributeExtractors so we don't have to load the
* class loaded repeatedly when accessing custom attributes.
*/
private static Map m_extractorCache = new HashMap();
/**
* Return the list (possibly empty) of custom attributes associated
* with the class "klass".
*
* @param klass The java.lang.Class object to find the attributes on.
* @return The possibly 0-length array of attributes
*/
public static Object[] getAttributes(final Class klass) {
return getAttrExtractor(klass).getClassAttributes();
}
/**
* Return all the attributes associated with the given method.
*
* @param method The java.lang.reflect.Method describing the method.
* @return Attribute[] all attributes associated with the method.
* Returns a 0 length array in case no attributes were found.
*/
public static Object[] getAttributes(final Method method) {
Class klass = method.getDeclaringClass();
ArrayList attribList = new ArrayList();
// search for superclass
while (true) {
Object[] returnAttribs = searchForMethodAttribs(klass, method);
if (returnAttribs.length > 0) {
// already in the list and the attribute is allowed to be specified mulitple times.
attribList.addAll(Arrays.asList(returnAttribs));
}
Class superClass = klass.getSuperclass();
if (superClass == null) {
break;
}
else if (superClass.getName().startsWith("java.")) {
break;
}
else {
klass = superClass;
}
}
// search for interfaces.
while (true) {
Class[] interfaceClasses = klass.getInterfaces();
for (int i = 0; i < interfaceClasses.length; i++) {
Object[] intAttribs = searchForMethodAttribs(interfaceClasses[i], method);
if (intAttribs.length > 0) {
attribList.addAll(Arrays.asList(intAttribs));
}
}
Class superClass = klass.getSuperclass();
if (superClass == null) {
break;
}
else if (superClass.getName().startsWith("java.")) {
break;
}
else {
klass = superClass;
}
}
return attribList.toArray(new Object[attribList.size()]);
}
/**
* Return the list (possibly empty) of custom attributes associated with the field.
*
* @param field The java.lang.reflect.Field object to find the attributes on.
* @return The possibly 0-length array of attributes
*/
public static Object[] getAttributes(final Field field) {
return getAttrExtractor(field.getDeclaringClass()).getFieldAttributes(field.getName());
}
/**
* Searches for method attributes
*
* @param klass
* @param method
* @return Attribute[]
*/
private static Object[] searchForMethodAttribs(final Class klass, final Method method) {
AttributeExtractor extractor = getAttrExtractor(klass);
if (extractor != null) {
String[] paramTypes = new String[method.getParameterTypes().length];
for (int i = 0; i < paramTypes.length; i++) {
String paramType = method.getParameterTypes()[i].getName();
// TODO: is this fix generic? are there other cases not handled?
// handle array types
if (paramType.startsWith("[L")) {
paramType = paramType.substring(2, paramType.length() - 1) + "[]";
}
paramTypes[i] = paramType;
}
return extractor.getMethodAttributes(method.getName(), paramTypes);
}
else {
return new Object[0];
}
}
/**
* Return the list (possibly empty) of custom attributes associated with the class.
*
* @param klass The Class object to find the attributes on.
* @return The possibly 0-length array of attributes
*/
private static synchronized AttributeExtractor getAttrExtractor(final Class klass) {
AttributeExtractor extractor = null;
if ((extractor = (AttributeExtractor)m_extractorCache.get(klass)) == null) {
String className = klass.getName();
try {
ClassLoader loader = klass.getClassLoader();
if (loader != null) {
// TODO: use factory
extractor = new BcelAttributeExtractor();
extractor.initialize(className, klass.getClassLoader());
m_extractorCache.put(klass, extractor);
}
}
catch (Exception e) {
throw new WrappedRuntimeException(e);
}
}
return extractor;
}
}