/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.openejb.util;
import org.apache.xbean.asm.ClassReader;
import org.apache.xbean.asm.Label;
import org.apache.xbean.asm.MethodVisitor;
import org.apache.xbean.asm.Type;
import org.apache.xbean.asm.commons.EmptyVisitor;
import org.apache.xbean.recipe.ParameterNameLoader;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.WeakHashMap;
import java.security.AccessController;
import java.security.PrivilegedAction;
/**
* Implementation of ParameterNameLoader that uses ASM to read the parameter names from the local variable table in the
* class byte code.
* <p/>
* This wonderful piece of code was taken from org.springframework.core.LocalVariableTableParameterNameDiscover
*/
public class AsmParameterNameLoader implements ParameterNameLoader {
public static void install(){
AccessController.doPrivileged(new PrivilegedAction() {
public Object run() {
try {
Field field = org.apache.xbean.recipe.ReflectionUtil.class.getDeclaredField("parameterNamesLoader");
field.setAccessible(true);
field.set(null, new AsmParameterNameLoader());
// if (field.get(null) == null){
// }
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
});
}
/**
* Weak map from Constructor to List<String>.
*/
private final WeakHashMap<Constructor, List<String>> constructorCache = new WeakHashMap<Constructor, List<String>>();
/**
* Weak map from Method to List<String>.
*/
private final WeakHashMap<Method, List<String>> methodCache = new WeakHashMap<Method, List<String>>();
/**
* Gets the parameter names of the specified method or null if the class was compiled without debug symbols on.
*
* @param method the method for which the parameter names should be retrieved
* @return the parameter names or null if the class was compilesd without debug symbols on
*/
public List<String> get(Method method) {
// check the cache
if (methodCache.containsKey(method)) {
return methodCache.get(method);
}
Map<Method, List<String>> allMethodParameters = getAllMethodParameters(method.getDeclaringClass(), method.getName());
return allMethodParameters.get(method);
}
/**
* Gets the parameter names of the specified constructor or null if the class was compiled without debug symbols on.
*
* @param constructor the constructor for which the parameters should be retrieved
* @return the parameter names or null if the class was compiled without debug symbols on
*/
public List<String> get(Constructor constructor) {
// check the cache
if (constructorCache.containsKey(constructor)) {
return constructorCache.get(constructor);
}
Map<Constructor, List<String>> allConstructorParameters = getAllConstructorParameters(constructor.getDeclaringClass());
return allConstructorParameters.get(constructor);
}
/**
* Gets the parameter names of all constructoror null if the class was compiled without debug symbols on.
*
* @param clazz the class for which the constructor parameter names should be retrieved
* @return a map from Constructor object to the parameter names or null if the class was compiled without debug symbols on
*/
public Map<Constructor, List<String>> getAllConstructorParameters(Class clazz) {
// Determine the constructors?
List<Constructor> constructors = new ArrayList<Constructor>(Arrays.asList(clazz.getConstructors()));
constructors.addAll(Arrays.asList(clazz.getDeclaredConstructors()));
if (constructors.isEmpty()) {
return Collections.emptyMap();
}
// Check the cache
if (constructorCache.containsKey(constructors.get(0))) {
Map<Constructor, List<String>> constructorParameters = new HashMap<Constructor, List<String>>();
for (Constructor constructor : constructors) {
constructorParameters.put(constructor, constructorCache.get(constructor));
}
return constructorParameters;
}
// Load the parameter names using ASM
Map<Constructor, List<String>> constructorParameters = new HashMap<Constructor, List<String>>();
try {
ClassReader reader = AsmParameterNameLoader.createClassReader(clazz);
AsmParameterNameLoader.AllParameterNamesDiscoveringVisitor visitor = new AsmParameterNameLoader.AllParameterNamesDiscoveringVisitor(clazz);
reader.accept(visitor, 0);
Map exceptions = visitor.getExceptions();
if (exceptions.size() == 1) {
throw new RuntimeException((Exception) exceptions.values().iterator().next());
}
if (!exceptions.isEmpty()) {
throw new RuntimeException(exceptions.toString());
}
constructorParameters = visitor.getConstructorParameters();
} catch (IOException ex) {
}
// Cache the names
for (Constructor constructor : constructors) {
constructorCache.put(constructor, constructorParameters.get(constructor));
}
return constructorParameters;
}
/**
* Gets the parameter names of all methods with the specified name or null if the class was compiled without debug symbols on.
*
* @param clazz the class for which the method parameter names should be retrieved
* @param methodName the of the method for which the parameters should be retrieved
* @return a map from Method object to the parameter names or null if the class was compiled without debug symbols on
*/
public Map<Method, List<String>> getAllMethodParameters(Class clazz, String methodName) {
// Determine the constructors?
Method[] methods = getMethods(clazz, methodName);
if (methods.length == 0) {
return Collections.emptyMap();
}
// Check the cache
if (methodCache.containsKey(methods[0])) {
Map<Method, List<String>> methodParameters = new HashMap<Method, List<String>>();
for (Method method : methods) {
methodParameters.put(method, methodCache.get(method));
}
return methodParameters;
}
// Load the parameter names using ASM
Map<Method, List<String>> methodParameters = new HashMap<Method, List<String>>();
try {
ClassReader reader = AsmParameterNameLoader.createClassReader(clazz);
AsmParameterNameLoader.AllParameterNamesDiscoveringVisitor visitor = new AsmParameterNameLoader.AllParameterNamesDiscoveringVisitor(clazz, methodName);
reader.accept(visitor, 0);
Map exceptions = visitor.getExceptions();
if (exceptions.size() == 1) {
throw new RuntimeException((Exception) exceptions.values().iterator().next());
}
if (!exceptions.isEmpty()) {
throw new RuntimeException(exceptions.toString());
}
methodParameters = visitor.getMethodParameters();
} catch (IOException ex) {
}
// Cache the names
for (Method method : methods) {
methodCache.put(method, methodParameters.get(method));
}
return methodParameters;
}
private Method[] getMethods(Class clazz, String methodName) {
List<Method> methods = new ArrayList<Method>(Arrays.asList(clazz.getMethods()));
methods.addAll(Arrays.asList(clazz.getDeclaredMethods()));
List<Method> matchingMethod = new ArrayList<Method>(methods.size());
for (Method method : methods) {
if (method.getName().equals(methodName)) {
matchingMethod.add(method);
}
}
return matchingMethod.toArray(new Method[matchingMethod.size()]);
}
private static ClassReader createClassReader(Class declaringClass) throws IOException {
InputStream in = null;
try {
ClassLoader classLoader = declaringClass.getClassLoader();
in = classLoader.getResourceAsStream(declaringClass.getName().replace('.', '/') + ".class");
ClassReader reader = new ClassReader(in);
return reader;
} finally {
if (in != null) {
try {
in.close();
} catch (IOException ignored) {
}
}
}
}
private static class AllParameterNamesDiscoveringVisitor extends EmptyVisitor {
private final Map<Constructor, List<String>> constructorParameters = new HashMap<Constructor, List<String>>();
private final Map<Method, List<String>> methodParameters = new HashMap<Method, List<String>>();
private final Map<String, Exception> exceptions = new HashMap<String, Exception>();
private final String methodName;
private final Map<String, Method> methodMap = new HashMap<String, Method>();
private final Map<String, Constructor> constructorMap = new HashMap<String, Constructor>();
public AllParameterNamesDiscoveringVisitor(Class type, String methodName) {
this.methodName = methodName;
List<Method> methods = new ArrayList<Method>(Arrays.asList(type.getMethods()));
methods.addAll(Arrays.asList(type.getDeclaredMethods()));
for (Method method : methods) {
if (method.getName().equals(methodName)) {
methodMap.put(Type.getMethodDescriptor(method), method);
}
}
}
public AllParameterNamesDiscoveringVisitor(Class type) {
this.methodName = "<init>";
List<Constructor> constructors = new ArrayList<Constructor>(Arrays.asList(type.getConstructors()));
constructors.addAll(Arrays.asList(type.getDeclaredConstructors()));
for (Constructor constructor : constructors) {
Type[] types = new Type[constructor.getParameterTypes().length];
for (int j = 0; j < types.length; j++) {
types[j] = Type.getType(constructor.getParameterTypes()[j]);
}
constructorMap.put(Type.getMethodDescriptor(Type.VOID_TYPE, types), constructor);
}
}
public Map<Constructor, List<String>> getConstructorParameters() {
return constructorParameters;
}
public Map<Method, List<String>> getMethodParameters() {
return methodParameters;
}
public Map<String, Exception> getExceptions() {
return exceptions;
}
public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
if (!name.equals(this.methodName)) {
return null;
}
try {
final List<String> parameterNames;
final boolean isStaticMethod;
if (methodName.equals("<init>")) {
Constructor constructor = constructorMap.get(desc);
if (constructor == null) {
return null;
}
parameterNames = new ArrayList<String>(constructor.getParameterTypes().length);
parameterNames.addAll(Collections.<String>nCopies(constructor.getParameterTypes().length, null));
constructorParameters.put(constructor, parameterNames);
isStaticMethod = false;
} else {
Method method = methodMap.get(desc);
if (method == null) {
return null;
}
parameterNames = new ArrayList<String>(method.getParameterTypes().length);
parameterNames.addAll(Collections.<String>nCopies(method.getParameterTypes().length, null));
methodParameters.put(method, parameterNames);
isStaticMethod = Modifier.isStatic(method.getModifiers());
}
return new EmptyVisitor() {
// assume static method until we get a first parameter name
public void visitLocalVariable(String name, String description, String signature, Label start, Label end, int index) {
if (isStaticMethod) {
if (index < parameterNames.size()) {
parameterNames.set(index, name);
}
} else if (index > 0) {
// for non-static the 0th arg is "this" so we need to offset by -1
index--;
if (index < parameterNames.size()) {
parameterNames.set(index, name);
}
}
}
};
} catch (Exception e) {
this.exceptions.put(signature, e);
}
return null;
}
}
}