org.apache.hadoop.hive.ql.exec.AddToClassPathAction Maven / Gradle / Ivy
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* 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.hadoop.hive.ql.exec;
import java.net.URL;
import java.security.PrivilegedAction;
import java.util.List;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
/**
* Helper class to create UDFClassLoader when running under a security manager. To create a class loader:
* > AddToClassPathAction addAction = new AddToClassPathAction(parentLoader, newPaths, true);
* > UDFClassLoader childClassLoader = AccessController.doPrivileged(addAction);
* To try to add to the class path of the existing class loader; call the above without forceNewClassLoader=true.
* Note that a class loader might be still created as fallback method.
*
* This is slightly inconvenient, but forces the caller code to make the doPriviliged call, rather than us making the
* call on the caller's behalf, in accordance with the security guidelines at:
* https://docs.oracle.com/javase/8/docs/technotes/guides/security/doprivileged.html
*/
public class AddToClassPathAction implements PrivilegedAction {
private final ClassLoader parentLoader;
private final Collection newPaths;
private final boolean forceNewClassLoader;
public AddToClassPathAction(ClassLoader parentLoader, Collection newPaths, boolean forceNewClassLoader) {
this.parentLoader = parentLoader;
this.newPaths = newPaths != null ? newPaths : Collections.EMPTY_LIST;
this.forceNewClassLoader = forceNewClassLoader;
if (parentLoader == null) {
throw new IllegalArgumentException("UDFClassLoader is not designed to be a bootstrap class loader!");
}
}
public AddToClassPathAction(ClassLoader parentLoader, Collection newPaths) {
this(parentLoader, newPaths, false);
}
@Override
public UDFClassLoader run() {
if (useExistingClassLoader()) {
final UDFClassLoader udfClassLoader = (UDFClassLoader) parentLoader;
for (String path : newPaths) {
udfClassLoader.addURL(Utilities.urlFromPathString(path));
}
return udfClassLoader;
} else {
return createUDFClassLoader();
}
}
private boolean useExistingClassLoader() {
if (!forceNewClassLoader && parentLoader instanceof UDFClassLoader) {
final UDFClassLoader udfClassLoader = (UDFClassLoader) parentLoader;
// The classloader may have been closed, Cannot add to the same instance
return !udfClassLoader.isClosed();
}
// Cannot use the same classloader if it is not an instance of {@code UDFClassLoader}, or new loader was explicily
// requested
return false;
}
private UDFClassLoader createUDFClassLoader() {
List urls = new ArrayList<>();
for (String path : newPaths) {
URL url = Utilities.urlFromPathString(path);
if (url != null) {
urls.add(url);
}
}
return new UDFClassLoader(urls.toArray(new URL[urls.size()]), parentLoader);
}
}