/* | |
* 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.aries.proxy.impl.interfaces; | |
import java.lang.ref.WeakReference; | |
import java.lang.reflect.Constructor; | |
import java.lang.reflect.Modifier; | |
import java.util.Arrays; | |
import java.util.Collection; | |
import java.util.Comparator; | |
import java.util.Map; | |
import java.util.SortedSet; | |
import java.util.TreeSet; | |
import java.util.WeakHashMap; | |
import java.util.concurrent.Callable; | |
import org.apache.aries.proxy.FinalModifierException; | |
import org.apache.aries.proxy.InvocationListener; | |
import org.apache.aries.proxy.UnableToProxyException; | |
import org.objectweb.asm.ClassVisitor; | |
import org.objectweb.asm.Opcodes; | |
import org.osgi.framework.Bundle; | |
import org.osgi.framework.wiring.BundleWiring; | |
/** | |
* This class is used to aggregate several interfaces into a real class which implements all of them | |
* It also allows you specify a superclass that the class should implement - this will add delegating | |
* method overrides for any abstract methods in the hierarchy, but not override any non-abstract methods. | |
* To be safely used as a supertype the superclass should be a WovenProxy. | |
*/ | |
public final class InterfaceProxyGenerator extends ClassVisitor implements Opcodes { | |
public InterfaceProxyGenerator() | |
{ | |
super(Opcodes.ASM5); | |
} | |
private static final Map<BundleWiring, WeakReference<ProxyClassLoader>> cache = | |
new WeakHashMap<BundleWiring, WeakReference<ProxyClassLoader>>(128); | |
/** | |
* Generate a new proxy instance implementing the supplied interfaces and using the supplied | |
* dispatcher and listener | |
* @param client the bundle that is trying to generate this proxy (can be null) | |
* @param superclass The superclass to use (or null for Object) | |
* @param ifaces The set of interfaces to implement (may be empty if superclass is non null) | |
* @param dispatcher | |
* @param listener | |
* @return | |
* @throws UnableToProxyException | |
*/ | |
public static Object getProxyInstance(Bundle client, Class<?> superclass, | |
Collection<Class<?>> ifaces, Callable<Object> dispatcher, InvocationListener listener) throws UnableToProxyException{ | |
if(superclass != null && (superclass.getModifiers() & Modifier.FINAL) != 0) | |
throw new FinalModifierException(superclass); | |
ProxyClassLoader pcl = null; | |
SortedSet<Class<?>> interfaces = createSet(ifaces); | |
synchronized (cache) { | |
BundleWiring wiring = client == null ? null : (BundleWiring)client.adapt(BundleWiring.class); | |
WeakReference<ProxyClassLoader> ref = cache.get(wiring); | |
if(ref != null) | |
pcl = ref.get(); | |
if (pcl != null && pcl.isInvalid(interfaces)) { | |
pcl = null; | |
cache.remove(wiring); | |
} | |
if(pcl == null) { | |
pcl = new ProxyClassLoader(client); | |
cache.put(wiring, new WeakReference<ProxyClassLoader>(pcl)); | |
} | |
} | |
Class<?> c = pcl.createProxyClass(superclass, interfaces); | |
try { | |
Constructor<?> con = c.getDeclaredConstructor(Callable.class, InvocationListener.class); | |
con.setAccessible(true); | |
return con.newInstance(dispatcher, listener); | |
} catch (Exception e) { | |
throw new UnableToProxyException(ifaces.iterator().next(), e); | |
} | |
} | |
/** | |
* Get the set of interfaces we need to process. This will return a HashSet | |
* that includes includes the supplied collection and any super-interfaces of | |
* those classes | |
* @param ifaces | |
* @return | |
*/ | |
private static SortedSet<Class<?>> createSet(Collection<Class<?>> ifaces) { | |
SortedSet<Class<?>> classes = new TreeSet<Class<?>>(new Comparator<Class<?>>() { | |
public int compare(Class<?> object1, Class<?> object2) { | |
if (object1.getName().equals(object2.getName())) { | |
return 0; | |
} else if (object1.isAssignableFrom(object2)) { | |
// first class is parent of second, it occurs earlier in type hierarchy | |
return -1; | |
} else if (object2.isAssignableFrom(object1)) { | |
// second class is subclass of first one, it occurs later in hierarchy | |
return 1; | |
} | |
// types have separate inheritance trees, so it doesn't mater which one is first or second, | |
// however we can't mark them as equal cause one of them will be removed | |
return 1; | |
} | |
}); | |
for(Class<?> c : ifaces) { | |
//If we already have a class contained then we have already covered its hierarchy | |
if(classes.add(c)) | |
classes.addAll(createSet(Arrays.asList(c.getInterfaces()))); | |
} | |
return classes; | |
} | |
} |