/*
* Copyright 2002-2008 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;
import java.lang.instrument.ClassFileTransformer;
/**
* Defines the contract for adding one or more
* {@link ClassFileTransformer ClassFileTransformers} to a {@link ClassLoader}.
*
* <p>Implementations may operate on the current context <code>ClassLoader</code>
* or expose their own instrumentable <code>ClassLoader</code>.
*
* @author Rod Johnson
* @author Costin Leau
* @since 2.0
* @see java.lang.instrument.ClassFileTransformer
*/
public interface LoadTimeWeaver {
/**
* Add a <code>ClassFileTransformer</code> to be applied by this
* <code>LoadTimeWeaver</code>.
* @param transformer the <code>ClassFileTransformer</code> to add
*/
void addTransformer(ClassFileTransformer transformer);
/**
* Return a <code>ClassLoader</code> that supports instrumentation
* through AspectJ-style load-time weaving based on user-defined
* {@link ClassFileTransformer ClassFileTransformers}.
* <p>May be the current <code>ClassLoader</code>, or a <code>ClassLoader</code>
* created by this {@link LoadTimeWeaver} instance.
* @return the <code>ClassLoader</code> which will expose
* instrumented classes according to the registered transformers
*/
ClassLoader getInstrumentableClassLoader();
/**
* Return a throwaway <code>ClassLoader</code>, enabling classes to be
* loaded and inspected without affecting the parent <code>ClassLoader</code>.
* <p>Should <i>not</i> return the same instance of the {@link ClassLoader}
* returned from an invocation of {@link #getInstrumentableClassLoader()}.
* @return a temporary throwaway <code>ClassLoader</code>; should return
* a new instance for each call, with no existing state
*/
ClassLoader getThrowawayClassLoader();
}
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