/*
* 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 com.facebook.presto.operator.aggregation;
import com.facebook.presto.byteCode.DynamicClassLoader;
import com.google.common.base.Throwables;
import com.google.common.collect.ImmutableMap;
import com.google.common.io.ByteStreams;
import java.io.IOException;
import java.io.InputStream;
import java.util.Map;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkState;
public final class IsolatedClass
{
private IsolatedClass() {}
public static <T> Class<? extends T> isolateClass(Class<T> publicBaseClass, Class<? extends T> implementationClass, Class<?>... additionalClasses)
{
return isolateClass(new DynamicClassLoader(publicBaseClass.getClassLoader()), publicBaseClass, implementationClass, additionalClasses);
}
public static <T> Class<? extends T> isolateClass(
DynamicClassLoader dynamicClassLoader,
Class<T> publicBaseClass,
Class<? extends T> implementationClass,
Class<?>... additionalClasses)
{
ImmutableMap.Builder<String, byte[]> builder = ImmutableMap.builder();
builder.put(implementationClass.getName(), getByteCode(implementationClass));
for (Class<?> additionalClass : additionalClasses) {
builder.put(additionalClass.getName(), getByteCode(additionalClass));
}
// load classes into a private class loader
Map<String, Class<?>> isolatedClasses = dynamicClassLoader.defineClasses(builder.build());
Class<?> isolatedClass = isolatedClasses.get(implementationClass.getName());
// verify the isolated class
checkArgument(isolatedClass != null, "Could load class %s", implementationClass.getName());
checkArgument(publicBaseClass.isAssignableFrom(isolatedClass),
"Error isolating class %s, newly loaded class is not a sub type of %s",
implementationClass.getName(),
publicBaseClass.getName());
checkState(isolatedClass != implementationClass, "Isolation failed");
return isolatedClass.asSubclass(publicBaseClass);
}
private static byte[] getByteCode(Class<?> clazz)
{
InputStream stream = clazz.getClassLoader().getResourceAsStream(clazz.getName().replace('.', '/') + ".class");
checkArgument(stream != null, "Could not obtain byte code for class %s", clazz.getName());
try {
return ByteStreams.toByteArray(stream);
}
catch (IOException e) {
throw Throwables.propagate(e);
}
}
}