question: DGCAckHandler ( UID id ) { this . id = id ; if ( id != null ) { assert ! idTable . containsKey ( id ) ; idTable . put ( id , this ) ; } }
target:  Creates a new DGCAckHandler, associated with the specified UID if the argument is not null. References added to this DGCAckHandler will be held strongly until its "release" method is invoked or (after the "startTimer" method has been invoked) the timeout has expired. If the argument is not null, then invoking the static "received" method with the specified UID is equivalent to invoking this instance's "release" method.