/*
* Copyright 2011 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.powermock.core;
import javassist.ClassPool;
import javassist.CtClass;
import javassist.CtConstructor;
import javassist.CtMethod;
import javassist.CtNewMethod;
import javassist.Modifier;
import javassist.NotFoundException;
import org.powermock.reflect.internal.TypeUtils;
import java.util.concurrent.atomic.AtomicInteger;
/**
* This class takes care of creating a concrete sub-class implementing all
* abstract methods in the parent.
*/
public class ConcreteClassGenerator {
// Used to make each new subclass of a specific type unique.
private static AtomicInteger counter = new AtomicInteger(0);
public Class<?> createConcreteSubClass(Class<?> clazz) {
if (clazz == null) {
throw new IllegalArgumentException("clazz cannot be null");
}
if (!java.lang.reflect.Modifier.isAbstract(clazz.getModifiers())) {
throw new IllegalArgumentException("clazz must be abstract");
}
ClassPool classpool = ClassPool.getDefault();
final String originalClassName = clazz.getName();
final CtClass originalClassAsCtClass;
final CtClass newClass = classpool.makeClass(generateClassName(clazz));
try {
newClass.setSuperclass(classpool.get(clazz.getName()));
} catch (Exception e1) {
throw new RuntimeException(e1);
}
try {
originalClassAsCtClass = classpool.get(originalClassName);
CtMethod[] declaredMethods = originalClassAsCtClass.getDeclaredMethods();
for (CtMethod ctMethod : declaredMethods) {
if (Modifier.isAbstract(ctMethod.getModifiers())) {
final String code = getReturnCode(ctMethod.getReturnType());
CtNewMethod.make(ctMethod.getReturnType(), ctMethod.getName(), ctMethod.getParameterTypes(),
ctMethod.getExceptionTypes(), code, newClass);
}
}
if (!hasInheritableConstructor(originalClassAsCtClass)) {
return null;
}
return newClass.toClass(this.getClass().getClassLoader(), this.getClass().getProtectionDomain());
} catch (Exception e) {
throw new RuntimeException(e);
}
}
private boolean hasInheritableConstructor(CtClass cls) throws NotFoundException {
CtConstructor[] constructors = cls.getDeclaredConstructors();
if (constructors.length == 0) {
return true;
}
for (CtConstructor ctConstructor : constructors) {
int modifiers = ctConstructor.getModifiers();
if (!Modifier.isPackage(modifiers) && !Modifier.isPrivate(modifiers)) {
return true;
}
}
return false;
}
private String getReturnCode(CtClass returnType) {
if (returnType.equals(CtClass.voidType)) {
return "{}";
}
return "{return " + TypeUtils.getDefaultValueAsString(returnType.getName()) + ";}";
}
private <T> String generateClassName(final Class<T> clazz) {
return "subclass." + clazz.getName() + "$$PowerMock" + counter.getAndIncrement();
}
}