org.apache.catalina.tribes.io.ReplicationStream Maven / Gradle / Ivy
/*
* 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.catalina.tribes.io;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectStreamClass;
import java.lang.reflect.Modifier;
import java.lang.reflect.Proxy;
import org.apache.catalina.tribes.util.StringManager;
/**
* Custom subclass of ObjectInputStream that loads from the
* class loader for this web application. This allows classes defined only
* with the web application to be found correctly.
*
* @author Craig R. McClanahan
* @author Bip Thelin
*/
public final class ReplicationStream extends ObjectInputStream {
static final StringManager sm = StringManager.getManager(ReplicationStream.class);
/**
* The class loader we will use to resolve classes.
*/
private ClassLoader[] classLoaders = null;
/**
* Construct a new instance of CustomObjectInputStream
*
* @param stream The input stream we will read from
* @param classLoaders The class loader array used to instantiate objects
*
* @exception IOException if an input/output error occurs
*/
public ReplicationStream(InputStream stream,
ClassLoader[] classLoaders)
throws IOException {
super(stream);
this.classLoaders = classLoaders;
}
/**
* Load the local class equivalent of the specified stream class
* description, by using the class loader assigned to this Context.
*
* @param classDesc Class description from the input stream
*
* @exception ClassNotFoundException if this class cannot be found
* @exception IOException if an input/output error occurs
*/
@Override
public Class resolveClass(ObjectStreamClass classDesc)
throws ClassNotFoundException, IOException {
String name = classDesc.getName();
try {
return resolveClass(name);
} catch (ClassNotFoundException e) {
return super.resolveClass(classDesc);
}
}
public Class resolveClass(String name) throws ClassNotFoundException {
boolean tryRepFirst = name.startsWith("org.apache.catalina.tribes");
try {
if (tryRepFirst) {
return findReplicationClass(name);
} else {
return findExternalClass(name);
}
} catch (Exception x) {
if (tryRepFirst) {
return findExternalClass(name);
} else {
return findReplicationClass(name);
}
}
}
/**
* ObjectInputStream.resolveProxyClass has some funky way of using
* the incorrect class loader to resolve proxy classes, let's do it our way instead
*/
@Override
protected Class resolveProxyClass(String[] interfaces)
throws IOException, ClassNotFoundException {
ClassLoader latestLoader;
if (classLoaders.length > 0) {
latestLoader = classLoaders[0];
} else {
latestLoader = null;
}
ClassLoader nonPublicLoader = null;
boolean hasNonPublicInterface = false;
// define proxy in class loader of non-public interface(s), if any
Class[] classObjs = new Class[interfaces.length];
for (int i = 0; i < interfaces.length; i++) {
Class cl = this.resolveClass(interfaces[i]);
if (latestLoader==null) {
latestLoader = cl.getClassLoader();
}
if ((cl.getModifiers() & Modifier.PUBLIC) == 0) {
if (hasNonPublicInterface) {
if (nonPublicLoader != cl.getClassLoader()) {
throw new IllegalAccessError(
sm.getString("replicationStream.conflict"));
}
} else {
nonPublicLoader = cl.getClassLoader();
hasNonPublicInterface = true;
}
}
classObjs[i] = cl;
}
try {
return Proxy.getProxyClass(hasNonPublicInterface ? nonPublicLoader
: latestLoader, classObjs);
} catch (IllegalArgumentException e) {
throw new ClassNotFoundException(null, e);
}
}
public Class findReplicationClass(String name)
throws ClassNotFoundException {
Class clazz = Class.forName(name, false, getClass().getClassLoader());
return clazz;
}
public Class findExternalClass(String name) throws ClassNotFoundException {
ClassNotFoundException cnfe = null;
for (ClassLoader classLoader : classLoaders) {
try {
Class clazz = Class.forName(name, false, classLoader);
return clazz;
} catch (ClassNotFoundException x) {
cnfe = x;
}
}
if ( cnfe != null ) {
throw cnfe;
} else {
throw new ClassNotFoundException(name);
}
}
@Override
public void close() throws IOException {
this.classLoaders = null;
super.close();
}
}