/*
* Copyright 2012 Red Hat, Inc. and/or its affiliates.
*
* Licensed under the Eclipse Public License version 1.0, available at
* http://www.eclipse.org/legal/epl-v10.html
*/
package org.jboss.forge.furnace.proxy;
import java.lang.ref.WeakReference;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import javassist.util.proxy.MethodFilter;
import javassist.util.proxy.Proxy;
import javassist.util.proxy.ProxyFactory;
import javassist.util.proxy.ProxyObject;
/**
* @author <a href="mailto:lincolnbaxter@gmail.com">Lincoln Baxter, III</a>
*/
public class Proxies
{
private static Map<Integer, WeakReference<Class<?>>> cache = new ConcurrentHashMap<Integer, WeakReference<Class<?>>>();
private static MethodFilter filter = new MethodFilter()
{
@Override
public boolean isHandled(Method method)
{
String name = method.getName();
Class<?>[] parameterTypes = method.getParameterTypes();
if (!method.getDeclaringClass().getName().contains("java.lang")
|| ("clone".equals(name) && parameterTypes.length == 0)
|| ("equals".equals(name) && parameterTypes.length == 1)
|| ("hashCode".equals(name) && parameterTypes.length == 0)
|| ("toString".equals(name) && parameterTypes.length == 0))
return true;
return false;
}
};
/**
* Create a proxy for the given {@link Class} type.
*/
@SuppressWarnings("unchecked")
public static <T> T enhance(final ClassLoader loader, Object instance, ForgeProxy handler)
{
Class<?> type = Proxies.unwrapProxyTypes(instance.getClass(), loader);
Object result = null;
Class<?> proxyType = null;
WeakReference<Class<?>> ref = cache.get(type.hashCode());
if (ref != null)
{
proxyType = ref.get();
}
if (proxyType == null)
{
Class<?>[] hierarchy = null;
Class<?> superclass = null;
hierarchy = ProxyTypeInspector.getCompatibleClassHierarchy(loader, type);
if (hierarchy == null || hierarchy.length == 0)
throw new IllegalArgumentException("Must specify at least one non-final type to enhance for Object: "
+ instance + " of type " + instance.getClass());
Class<?> first = hierarchy[0];
if (!first.isInterface() && !isProxyType(first))
{
superclass = Proxies.unwrapProxyTypes(first, loader);
hierarchy = Arrays.shiftLeft(hierarchy, new Class<?>[hierarchy.length - 1]);
}
else if (isProxyType(first))
hierarchy = Arrays.shiftLeft(hierarchy, new Class<?>[hierarchy.length - 1]);
int index = Arrays.indexOf(hierarchy, ProxyObject.class);
if (index >= 0)
{
hierarchy = Arrays.removeElementAtIndex(hierarchy, index);
}
if (!Proxies.isProxyType(first) && !Arrays.contains(hierarchy, ForgeProxy.class))
hierarchy = Arrays.append(hierarchy, ForgeProxy.class);
ProxyFactory f = new ProxyFactory()
{
@Override
protected ClassLoader getClassLoader()
{
return loader;
}
};
f.setInterfaces(hierarchy);
f.setSuperclass(superclass);
f.setFilter(filter);
proxyType = f.createClass();
cache.put(type.hashCode(), new WeakReference<Class<?>>(proxyType));
}
try
{
result = proxyType.newInstance();
}
catch (InstantiationException e)
{
throw new IllegalStateException(
"Could not instantiate proxy for object [" + instance + "] of type [" + type
+ "]. For optimal proxy compatibility, ensure " +
"that this type is an interface, or a class with a default constructor.", e);
}
catch (IllegalAccessException e)
{
throw new IllegalStateException(e);
}
if (result instanceof Proxy)
((Proxy) result).setHandler(handler);
else if (result instanceof ProxyObject)
((ProxyObject) result).setHandler(handler);
else
throw new IllegalStateException("Could not set proxy handler [" + handler + "] for proxy object ["
+ result + "] for instance object [" + instance + "] of type [" + instance.getClass() + "]");
return (T) result;
}
/**
* Create a proxy for the given {@link Class} type.
*/
@SuppressWarnings("unchecked")
public static <T> T enhance(Class<T> type, ForgeProxy handler)
{
Object result = null;
Class<?> proxyType = null;
WeakReference<Class<?>> ref = cache.get(type.hashCode());
if (ref != null)
{
proxyType = ref.get();
}
if (proxyType == null)
{
Class<?>[] hierarchy = null;
Class<?> superclass = null;
if (type.isInterface() && !ForgeProxy.class.isAssignableFrom(type))
hierarchy = new Class<?>[] { type, ForgeProxy.class };
else if (type.isInterface())
hierarchy = new Class<?>[] { type };
else
{
if (Proxies.isProxyType(type))
superclass = unwrapProxyTypes(type);
else
{
superclass = type;
hierarchy = new Class<?>[] { ForgeProxy.class };
}
}
ProxyFactory f = new ProxyFactory();
f.setFilter(filter);
f.setInterfaces(hierarchy);
f.setSuperclass(superclass);
proxyType = f.createClass();
cache.put(type.hashCode(), new WeakReference<Class<?>>(proxyType));
}
try
{
result = proxyType.newInstance();
}
catch (InstantiationException e)
{
throw new IllegalStateException(
"Could not instantiate proxy for type [" + type
+ "]. For optimal proxy compatibility, ensure " +
"that this type is an interface, or a class with a default constructor.", e);
}
catch (IllegalAccessException e)
{
throw new IllegalStateException(e);
}
if (result instanceof Proxy)
((Proxy) result).setHandler(handler);
else if (result instanceof ProxyObject)
((ProxyObject) result).setHandler(handler);
else
throw new IllegalStateException("Could not set proxy handler [" + handler + "] for proxy object ["
+ result + "] for proxy of type [" + type + "]");
return (T) result;
}
public static boolean isProxyType(Class<?> type)
{
if (type.getName().contains("$$EnhancerByCGLIB$$")
|| type.getName().contains("_javassist_")
|| type.getName().contains("$Proxy$_$$_WeldClientProxy")
|| Proxy.class.isAssignableFrom(type)
|| ProxyObject.class.isAssignableFrom(type))
{
return true;
}
return false;
}
/**
* Returns the delegate object, if the given object was created via {@link Proxies}, otherwise it returns the given
* object, unchanged.
*/
@SuppressWarnings("unchecked")
public static <T> T unwrap(Object object)
{
T result = (T) object;
if (object != null)
{
while (isForgeProxy(result))
{
try
{
Method method = result.getClass().getMethod("getDelegate");
method.setAccessible(true);
result = (T) method.invoke(result);
}
catch (Exception e)
{
break;
}
}
if (result == null)
result = (T) object;
}
return result;
}
@SuppressWarnings("unchecked")
public static <T> T unwrapOnce(Object object)
{
T result = (T) object;
if (object != null)
{
if (isForgeProxy(result))
{
try
{
Method method = result.getClass().getMethod("getDelegate");
method.setAccessible(true);
result = (T) method.invoke(result);
}
catch (Exception e)
{
}
}
if (result == null)
result = (T) object;
}
return result;
}
/**
* Returns true if the given object was created via {@link Proxies}.
*/
public static boolean isForgeProxy(Object object)
{
if (object != null)
{
Class<?>[] interfaces = object.getClass().getInterfaces();
if (interfaces != null)
{
for (Class<?> iface : interfaces)
{
if (iface.getName().equals(ForgeProxy.class.getName()))
{
return true;
}
}
}
}
return false;
}
public static Class<?> unwrapProxyTypes(Class<?> type, ClassLoader... loaders)
{
Class<?> result = type;
if (isProxyType(result))
{
Class<?> superclass = result.getSuperclass();
while (superclass != null && !superclass.getName().equals(Object.class.getName()) && isProxyType(superclass))
{
superclass = superclass.getSuperclass();
}
if (superclass != null && !superclass.getName().equals(Object.class.getName()))
result = superclass;
String typeName = unwrapProxyClassName(result);
for (ClassLoader loader : loaders)
{
try
{
result = loader.loadClass(typeName);
break;
}
catch (ClassNotFoundException e)
{
}
}
}
return result;
}
/**
* Unwraps the proxy type if javassist or CGLib is used
*
* @param type the class type
* @return the unproxied class name
*/
public static String unwrapProxyClassName(Class<?> type)
{
String typeName;
if (type.getName().contains("$$EnhancerByCGLIB$$"))
{
typeName = type.getName().replaceAll("^(.*)\\$\\$EnhancerByCGLIB\\$\\$.*", "$1");
}
else if (type.getName().contains("_javassist_"))
{
typeName = type.getName().replaceAll("^(.*)_\\$\\$_javassist_.*", "$1");
}
else
{
typeName = type.getName();
}
return typeName;
}
/**
* This method tests if two proxied objects are equivalent.
*
* It does so by comparing the class names and the hashCode, since they may be loaded from different classloaders.
*
*/
public static boolean areEquivalent(Object proxiedObj, Object anotherProxiedObj)
{
if (proxiedObj == null && anotherProxiedObj == null)
{
return true;
}
else if (proxiedObj == null || anotherProxiedObj == null)
{
return false;
}
else
{
Object unproxiedObj = unwrap(proxiedObj);
Object anotherUnproxiedObj = unwrap(anotherProxiedObj);
boolean sameClassName = unwrapProxyClassName(unproxiedObj.getClass()).equals(
unwrapProxyClassName(anotherUnproxiedObj.getClass()));
if (sameClassName)
{
if (unproxiedObj.getClass().isEnum())
{
// Enum hashCode is different if loaded from different classloaders and cannot be overriden.
Enum<?> enumLeft = Enum.class.cast(unproxiedObj);
Enum<?> enumRight = Enum.class.cast(anotherUnproxiedObj);
return (enumLeft.name().equals(enumRight.name())) && (enumLeft.ordinal() == enumRight.ordinal());
}
else
{
return (unproxiedObj.hashCode() == anotherUnproxiedObj.hashCode());
}
}
else
{
return false;
}
}
}
/**
* Checks if a proxied object is an instance of the specified {@link Class}
*/
public static boolean isInstance(Class<?> type, Object proxiedObject)
{
return type.isInstance(unwrap(proxiedObject));
}
/**
* Determine whether or not a given {@link Class} type is instantiable.
*/
public static boolean isInstantiable(Class<?> type)
{
if (type != null)
{
try
{
if (type.isInterface())
return true;
type.getConstructor();
return true;
}
catch (SecurityException e)
{
return false;
}
catch (NoSuchMethodException e)
{
return false;
}
}
return false;
}
/**
* Determine if the given {@link Class} type does not require {@link ClassLoader} proxying.
*/
public static boolean isPassthroughType(Class<?> type)
{
boolean result = type.isArray()
|| type.getName().matches("^(java\\.lang).*")
|| type.getName().matches("^(java\\.io).*")
|| type.getName().matches("^(java\\.net).*")
|| type.isPrimitive();
result = result && !(Iterable.class.getName().equals(type.getName()));
return result;
}
public static boolean isLanguageType(Class<?> type)
{
boolean result = type.isArray()
|| type.getName().matches("^(java\\.).*")
|| type.isPrimitive();
return result;
}
public static boolean isCollectionType(Object instance)
{
boolean result = instance instanceof Collection
|| instance instanceof Iterable
|| instance.getClass().isArray();
return result;
}
}