/*
* Copyright 2006-2009 the original author or authors.
*
* 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 org.springframework.instrument.classloading.oc4j;
import java.lang.instrument.ClassFileTransformer;
import java.lang.instrument.IllegalClassFormatException;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.security.ProtectionDomain;
/**
* Adapter that implements OC4J ClassPreProcessor interface, delegating to a
* standard JDK {@link ClassFileTransformer} underneath.
*
* <p>To avoid compile time checks again the vendor API, a dynamic proxy is
* being used.
*
* @author Costin Leau
*/
class OC4JClassPreprocessorAdapter implements InvocationHandler {
private final ClassFileTransformer transformer;
/**
* Creates a new {@link OC4JClassPreprocessorAdapter}.
* @param transformer the {@link ClassFileTransformer} to be adapted (must
* not be <code>null</code>)
*/
public OC4JClassPreprocessorAdapter(ClassFileTransformer transformer) {
this.transformer = transformer;
}
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
String name = method.getName();
if ("equals".equals(name)) {
return (Boolean.valueOf(proxy == args[0]));
} else if ("hashCode".equals(name)) {
return hashCode();
} else if ("toString".equals(name)) {
return toString();
} else if ("initialize".equals(name)) {
initialize(proxy, (ClassLoader) args[0]);
return null;
} else if ("processClass".equals(name)) {
return processClass((String) args[0], (byte[]) args[1], (Integer) args[2], (Integer) args[3],
(ProtectionDomain) args[4], (ClassLoader) args[5]);
} else {
throw new IllegalArgumentException("Unknown method: " + method);
}
}
// maps to oracle.classloader.util.ClassPreprocessor#initialize
// the proxy is passed since it implements the Oracle interface which
// is asked as a return type
public Object initialize(Object proxy, ClassLoader loader) {
return proxy;
}
public byte[] processClass(String className, byte origClassBytes[], int offset, int length, ProtectionDomain pd,
ClassLoader loader) {
try {
byte[] tempArray = new byte[length];
System.arraycopy(origClassBytes, offset, tempArray, 0, length);
// NB: OC4J passes className as "." without class while the
// transformer expects a VM, "/" format
byte[] result = this.transformer.transform(loader, className.replace('.', '/'), null, pd, tempArray);
return (result != null ? result : origClassBytes);
} catch (IllegalClassFormatException ex) {
throw new IllegalStateException("Cannot transform because of illegal class format", ex);
}
}
@Override
public String toString() {
StringBuilder builder = new StringBuilder(getClass().getName());
builder.append(" for transformer: ");
builder.append(this.transformer);
return builder.toString();
}
}
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