ClassFileTransformers. These transformers can instrument
(or weave) the byte code of classes loaded through this class loader
to alter their behavior. Currently only
org.apache.catalina.loader.WebappClassLoaderBase implements this
interface. This allows web application frameworks or JPA providers
bundled with a web application to instrument web application classes
as necessary.
You should always program against the methods of this interface
(whether using reflection or otherwise). The methods in
WebappClassLoaderBase are protected by the default security
manager if one is in use.
| Modifier and Type | Method and Description |
|---|---|
| public void | addTransformer(ClassFileTransformer
The transformer to add to the class loader transformer)Adds the specified class file transformer to this class loader. |
| public ClassLoader | Returns: the transformer-free copy of this class loader.Returns a copy of this class loader without any class file transformers. |
| public void | removeTransformer(ClassFileTransformer
The transformer to remove transformer)Removes the specified class file transformer from this class loader. |
| addTransformer | back to summary |
|---|---|
| public void addTransformer(ClassFileTransformer transformer) Adds the specified class file transformer to this class loader. The transformer will then be able to instrument the bytecode of any classes loaded by this class loader after the invocation of this method.
| |
| copyWithoutTransformers | back to summary |
|---|---|
| public ClassLoader copyWithoutTransformers() Returns a copy of this class loader without any class file
transformers. This is a tool often used by Java Persistence API
providers to inspect entity classes in the absence of any
instrumentation, something that can't be guaranteed within the
context of a The returned class loader's resource cache will have been cleared so that classes already instrumented will not be retained or returned.
| |
| removeTransformer | back to summary |
|---|---|
| public void removeTransformer(ClassFileTransformer transformer) Removes the specified class file transformer from this class loader. It will no longer be able to instrument the byte code of any classes loaded by the class loader after the invocation of this method. However, any classes already instrumented by this transformer before this method call will remain in their instrumented state.
| |