package org.jmock.lib.legacy;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.List;
import net.sf.cglib.core.CodeGenerationException;
import net.sf.cglib.core.DefaultNamingPolicy;
import net.sf.cglib.core.NamingPolicy;
import net.sf.cglib.core.Predicate;
import net.sf.cglib.proxy.Callback;
import net.sf.cglib.proxy.CallbackFilter;
import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.Factory;
import net.sf.cglib.proxy.InvocationHandler;
import net.sf.cglib.proxy.NoOp;
import org.jmock.api.Imposteriser;
import org.jmock.api.Invocation;
import org.jmock.api.Invokable;
import org.jmock.internal.SearchingClassLoader;
import org.objenesis.Objenesis;
import org.objenesis.ObjenesisStd;
/**
* This class lets you imposterise abstract and concrete classes
* <em>without</em> calling the constructors of the mocked class.
*
* @author npryce
*/
public class ClassImposteriser implements Imposteriser {
public static final Imposteriser INSTANCE = new ClassImposteriser();
private ClassImposteriser() {}
private static final NamingPolicy NAMING_POLICY_THAT_ALLOWS_IMPOSTERISATION_OF_CLASSES_IN_SIGNED_PACKAGES = new DefaultNamingPolicy() {
@Override
public String getClassName(String prefix, String source, Object key, Predicate names) {
return "org.jmock.codegen." + super.getClassName(prefix, source, key, names);
}
};
private static final CallbackFilter IGNORE_BRIDGE_METHODS = new CallbackFilter() {
public int accept(Method method) {
return method.isBridge() ? 1 : 0;
}
};
private final Objenesis objenesis = new ObjenesisStd();
public boolean canImposterise(Class<?> type) {
return !type.isPrimitive() &&
!Modifier.isFinal(type.getModifiers()) &&
(type.isInterface() || !toStringMethodIsFinal(type));
}
public <T> T imposterise(final Invokable mockObject, Class<T> mockedType, Class<?>... ancilliaryTypes) {
if (!mockedType.isInterface() && toStringMethodIsFinal(mockedType)) {
throw new IllegalArgumentException(mockedType.getName() + " has a final toString method");
}
try {
setConstructorsAccessible(mockedType, true);
Class<?> proxyClass = createProxyClass(mockedType, ancilliaryTypes);
return mockedType.cast(createProxy(proxyClass, mockObject));
}
finally {
setConstructorsAccessible(mockedType, false);
}
}
private boolean toStringMethodIsFinal(Class<?> type) {
try {
Method toString = type.getMethod("toString");
return Modifier.isFinal(toString.getModifiers());
}
catch (SecurityException e) {
throw new IllegalStateException("not allowed to reflect on toString method", e);
}
catch (NoSuchMethodException e) {
throw new Error("no public toString method found", e);
}
}
private void setConstructorsAccessible(Class<?> mockedType, boolean accessible) {
for (Constructor<?> constructor : mockedType.getDeclaredConstructors()) {
constructor.setAccessible(accessible);
}
}
private <T> Class<?> createProxyClass(Class<?> mockedType, Class<?>... ancilliaryTypes) {
if (mockedType == Object.class) {
mockedType = ClassWithSuperclassToWorkAroundCglibBug.class;
}
Enhancer enhancer = new Enhancer() {
@Override
@SuppressWarnings("unchecked")
protected void filterConstructors(Class sc, List constructors) {
// Don't filter
}
};
enhancer.setClassLoader(SearchingClassLoader.combineLoadersOf(mockedType, ancilliaryTypes));
enhancer.setUseFactory(true);
if (mockedType.isInterface()) {
enhancer.setSuperclass(Object.class);
enhancer.setInterfaces(prepend(mockedType, ancilliaryTypes));
}
else {
enhancer.setSuperclass(mockedType);
enhancer.setInterfaces(ancilliaryTypes);
}
enhancer.setCallbackTypes(new Class[]{InvocationHandler.class, NoOp.class});
enhancer.setCallbackFilter(IGNORE_BRIDGE_METHODS);
if (mockedType.getSigners() != null) {
enhancer.setNamingPolicy(NAMING_POLICY_THAT_ALLOWS_IMPOSTERISATION_OF_CLASSES_IN_SIGNED_PACKAGES);
}
try {
return enhancer.createClass();
}
catch (CodeGenerationException e) {
// Note: I've only been able to manually test this. It exists to help people writing
// Eclipse plug-ins or using other environments that have sophisticated class loader
// structures.
throw new IllegalArgumentException("could not imposterise " + mockedType, e);
}
}
private Object createProxy(Class<?> proxyClass, final Invokable mockObject) {
Factory proxy = (Factory)objenesis.newInstance(proxyClass);
proxy.setCallbacks(new Callback[] {
new InvocationHandler() {
public Object invoke(Object receiver, Method method, Object[] args) throws Throwable {
return mockObject.invoke(new Invocation(receiver, method, args));
}
},
NoOp.INSTANCE
});
return proxy;
}
private Class<?>[] prepend(Class<?> first, Class<?>... rest) {
Class<?>[] all = new Class<?>[rest.length+1];
all[0] = first;
System.arraycopy(rest, 0, all, 1, rest.length);
return all;
}
public static class ClassWithSuperclassToWorkAroundCglibBug {}
}