I would like to use Byte Buddy together with OSGi weaving hook.
For instance, it is possible to use Javassist together with OSGi weaving hook like this:
//... other imports
import org.osgi.framework.hooks.weaving.WeavingHook;
import org.osgi.framework.hooks.weaving.WovenClass;
@Component (immediate = true)
public class MyWeavingHook implements WeavingHook {
@Activate
public void activate(ComponentContext ctx) {
System.out.print("Activating demo weaving hook...");
}
@Override
public void weave(WovenClass wovenClass) {
System.out.println("Weaving hook called on " + wovenClass.getClassName());
if (wovenClass.getClassName().equals("DecoratedTestServiceImpl")) {
try (InputStream is = new ByteArrayInputStream(wovenClass.getBytes())) {
ClassPool pool = ClassPool.getDefault();
CtClass ctClass = pool.makeClass(is);
ctClass.getDeclaredMethod("ping").setBody("return \"WAIVED\";");
wovenClass.setBytes(ctClass.toBytecode());
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
How to process the wovenClass with Byte Buddy? I see that I can get the bytecode out like this:
byte[] classBytes = new ByteBuddy()
.subclass(AClass.class)
.name("MyClass")
.method(named("theMethod"))
.intercept(FixedValue.value("Hello World!"))
.make()
.getBytes();
wovenClass.setBytes(classBytes);
But I cannot see how to provide the wovenClass bytecode as an input to Byte Buddy. I would need something like:
new ByteBuddy().rebase(wovenClass.getBytes())...
The rebase
method is overloaded and accepts a ClassFileLocator
as a second argument. You can provide the class bytes directly by providing an explicit mapping:
ClassFileLocator.Simple.of(wovenClass.getClassName(), wovenClass.getBytes())