001/**
002 * Copyright (c) 2011, The University of Southampton and the individual contributors.
003 * All rights reserved.
004 *
005 * Redistribution and use in source and binary forms, with or without modification,
006 * are permitted provided that the following conditions are met:
007 *
008 *   *  Redistributions of source code must retain the above copyright notice,
009 *      this list of conditions and the following disclaimer.
010 *
011 *   *  Redistributions in binary form must reproduce the above copyright notice,
012 *      this list of conditions and the following disclaimer in the documentation
013 *      and/or other materials provided with the distribution.
014 *
015 *   *  Neither the name of the University of Southampton nor the names of its
016 *      contributors may be used to endorse or promote products derived from this
017 *      software without specific prior written permission.
018 *
019 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
020 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
021 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
022 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
023 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
024 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
025 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
026 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
027 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
028 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
029 */
030package org.openimaj.citation;
031
032import javassist.CtClass;
033import javassist.CtMethod;
034
035import org.apache.log4j.Logger;
036import org.openimaj.aop.ClassTransformer;
037import org.openimaj.citation.annotation.Reference;
038import org.openimaj.citation.annotation.References;
039
040/**
041 * {@link ClassTransformer} that dynamically augments classes and methods
042 * annotated with {@link Reference} or {@link References} annotations to
043 * register the annotations with a global listener if the class is constructed,
044 * or the method is invoked.
045 * <p>
046 * When used with the {@link CitationAgent}, this can be used to dynamically
047 * produce a list of references for code as it is run. Importantly, the list
048 * will only contain references for the bits of code that are actually used!
049 * 
050 * @author Jonathon Hare (jsh2@ecs.soton.ac.uk)
051 * 
052 */
053public class ReferencesClassTransformer implements ClassTransformer {
054        private static Logger logger = Logger.getLogger(ReferencesClassTransformer.class);
055
056        @Override
057        public void transform(String className, CtClass ctclz) throws Exception {
058                Object ann = ctclz.getAnnotation(Reference.class);
059                if (ann == null)
060                        ann = ctclz.getAnnotation(References.class);
061
062                if (ann != null) {
063                        logger.trace(String.format("class file transformer invoked for className: %s\n", className));
064
065                        ctclz.makeClassInitializer().insertBefore(
066                                        ReferenceListener.class.getName() + ".addReference(" + ctclz.getName() + ".class);");
067                }
068
069                final CtMethod[] methods = ctclz.getDeclaredMethods();
070                for (final CtMethod m : methods) {
071                        ann = m.getAnnotation(Reference.class);
072                        if (ann == null)
073                                ann = m.getAnnotation(References.class);
074
075                        if (ann != null) {
076                                logger.trace(String.format("class file transformer invoked for className: %s\n; method: ", className,
077                                                m.getLongName()));
078
079                                final String code = ReferenceListener.class.getName() + ".addReference(" + ctclz.getName()
080                                                + ".class,\"" + m.getName() + "\",\"" + m.getLongName() + "\");";
081
082                                m.insertBefore(code);
083                        }
084                }
085        }
086}