| Re: [aspectj-users] WeavingAdapter - how to use it? |
| Hello, I looked through AspectJ's Load Time Weaver and I combined it with your code suggestion. This is what I got out import java.lang.instrument.ClassFileTransformer; import java.lang.instrument.IllegalClassFormatException; import java.security.ProtectionDomain; import java.util.ArrayList; import java.util.Arrays; import java.util.List; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; import org.aspectj.weaver.loadtime.Aj; import org.aspectj.weaver.loadtime.DefaultWeavingContext; import org.aspectj.weaver.loadtime.definition.Definition; import org.aspectj.weaver.tools.WeavingAdaptor; public class AspectJLTW implements ClassFileTransformer { private class MonitorWeavingContext extends DefaultWeavingContext { public MonitorWeavingContext(ClassLoader loader) { super(loader); } @Override public List getDefinitions(ClassLoader loader, WeavingAdaptor adaptor) { List definitions = new ArrayList(); Definition d = new Definition(); d.getAspectClassNames().add(aspectName); d.appendWeaverOptions("-Xjoinpoints:synchronization"); definitions.add(d); return definitions; } } private final Map<ClassLoader, Aj> mapFromClassLoaderToAj; private final String aspectName; public AspectJLTW(String aspectName) { try { mapFromClassLoaderToAj = new ConcurrentHashMap<ClassLoader, Aj>(); this.aspectName = aspectName; } catch (Exception e) { throw new ExceptionInInitializerError( "could not initialize JSR163 preprocessor due to: " + e.toString()); } } /** * Weaving delegation * * @param loader * the defining class loader * @param className * the name of class beeing loaded * @param classBeingRedefined * when hotswap is called * @param protectionDomain * @param bytes * the bytecode before weaving * @return the weaved bytecode */ public byte[] transform(ClassLoader loader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] bytes) throws IllegalClassFormatException { if (className.replace("/", ".").equals(aspectName)) return null; Aj aj = getInstrumenter(loader); byte[] b = aj.preProcess(className, bytes, loader); if (Arrays.equals(bytes, b)) return null; return b; } private Aj getInstrumenter(ClassLoader loader) { if (mapFromClassLoaderToAj.containsKey(loader)) { return mapFromClassLoaderToAj.get(loader); } Aj aj = new Aj(new MonitorWeavingContext(loader)); mapFromClassLoaderToAj.put(loader, aj); return aj; } } If you add "-Xbootclasspath/p:<path_to_aspects.jar>" JVM option, then you can instrument inside the JDKs and also instrument already loaded classes. I tried it on Java 1.6.0_15 on Mac OSX. One little note: JVM complains about java.lang.UnsupportedOperationException: class redefinition failed: attempted to change the schema (add/remove fields). I suspect t has something to do with AspectJ adding extra fields. Is there a way to force inlining of the aspects? Best regards, Silviu On Nov 22, 2009, at 12:18 AM, Andy Clement wrote:
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