juzu.impl.common.DevClassLoader Maven / Gradle / Ivy
/*
* Copyright 2013 eXo Platform SAS
*
* 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 juzu.impl.common;
import java.io.IOException;
import java.net.URL;
import java.util.Enumeration;
import java.util.NoSuchElementException;
/**
* The DevClassLoader blacklists any class from found in the /WEB-INF/classes folder
* and instead throws a {@link ClassNotFoundException} to the caller, forcing the caller to load the class by
* itself. At the moment it only supports unpacked war files.
*
* @author Julien Viet
*/
public class DevClassLoader extends ClassLoader {
public DevClassLoader(ClassLoader parent) {
super(parent);
}
@Override
protected Class loadClass(String name, boolean resolve) throws ClassNotFoundException {
Class found = super.loadClass(name, resolve);
//
if (found.getClassLoader() == super.getParent()) {
String classPath = name.replace('.', '/') + ".class";
URL url = getResource(classPath);
if (url == null) {
throw new ClassNotFoundException();
}
}
//
return found;
}
@Override
public URL getResource(String name) {
URL url = super.getResource(name);
//
if (url != null && shouldLoad(url, name)) {
return url;
}
else {
try {
Enumeration e = getResources(name);
if (e.hasMoreElements()) {
return e.nextElement();
}
}
catch (IOException ignore) {
//
}
return null;
}
}
@Override
public Enumeration getResources(final String name) throws IOException {
final Enumeration a = super.getResources(name);
return new Enumeration() {
URL next = null;
public boolean hasMoreElements() {
while (next == null && a.hasMoreElements()) {
URL url = a.nextElement();
if (shouldLoad(url, name)) {
next = url;
}
}
return next != null;
}
public URL nextElement() {
if (!hasMoreElements()) {
throw new NoSuchElementException("No more elements");
}
try {
return next;
}
finally {
next = null;
}
}
};
}
private boolean shouldLoad(URL url, String name) {
// Unwrap until we get the file location
String protocol = url.getProtocol();
if ("file".equals(protocol)) {
String path = url.getPath();
if (path.endsWith("/WEB-INF/classes/" + name)) {
return false;
}
else {
return true;
}
}
else if ("jar".equals(protocol)) {
String path = url.getPath();
int index = path.indexOf("!/");
String nested = path.substring(0, index);
if (nested.endsWith(".jar") || nested.endsWith(".zip")) {
return true;
}
else {
throw new UnsupportedOperationException("handle me gracefully " + url);
}
}
else {
throw new UnsupportedOperationException("handle me gracefully " + url);
}
}
}