/**
* 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.geronimo.transformer;
import java.lang.instrument.ClassDefinition;
import java.lang.instrument.Instrumentation;
import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.UnmodifiableClassException;
/**
* @version $Rev: 1213810 $ $Date: 2011-12-14 02:00:08 +0800 (Wed, 14 Dec 2011) $
*/
public class TransformerAgent {
private static final String REDEFINE_CLASSES_PROPERTY = "org.apache.geronimo.transformer.redefineClasses";
private static Instrumentation instrumentation;
private static final TransformerCollection transformerCollection = new TransformerCollection();
public static void premain(String args, Instrumentation inst) {
inst.addTransformer(transformerCollection);
String redefineClasses = System.getProperty(REDEFINE_CLASSES_PROPERTY, "true");
if ("true".equalsIgnoreCase(redefineClasses)) {
instrumentation = inst;
}
}
public static void addTransformer(ClassFileTransformer classFileTransformer) {
transformerCollection.addTransformer(classFileTransformer);
}
public static void removeTransformer(ClassFileTransformer classFileTransformer) {
transformerCollection.removeTransformer(classFileTransformer);
}
public static boolean isRedefineClassesSupported() {
return instrumentation != null && instrumentation.isRedefineClassesSupported();
}
public static void redefine(ClassDefinition... definitions) throws UnmodifiableClassException {
if (!isRedefineClassesSupported()) {
throw new UnmodifiableClassException("Class redefinition is not supported");
}
try {
instrumentation.redefineClasses(definitions);
} catch (ClassNotFoundException e) {
UnmodifiableClassException ex = new UnmodifiableClassException();
ex.initCause(e);
throw ex;
}
}
}