private <Type extends Message>RpcCallback<Type> wrapsCallback(MockCallback<?> callback){
  EasyMock.reportMatcher(new WrapsCallback(callback));
  return null;
}

private < Type extends Message > RpcCallback < Type > wrapsCallback ( MockCallback < ? > callback ) { EasyMock . reportMatcher ( new WrapsCallback ( callback ) ) ; return null ; }
wrapscallback ( ) is an easymock argument predicate . wrapscallback ( c ) matches a callback if calling that callback causes c to be called . in other words , c wraps the given callback .
