DatagramSocket to be used both for sending and receiving multicast datagrams.
We propose to "move"
joinGroup(SocketAddress, NetworkInterface) and
leaveGroup(SocketAddress, NetworkInterface) up from
DatagramSocket has a
DatagramSocket.setDatagramSocketImplFactory method that allows to globally replace the default
MulticastSocket implementation provided by the JDK. This was provided as a way in early JDK releases to replace the system wide implementation. It has been mostly obsolete since Java 1.4. A
DatagramSocket can be created to use a custom implementation by extending
DatagramSocket and using the protected constructor that takes the impl as a parameter. However,
MulticastSocket doesn't provide such a constructor.
DatagramSocket can be subclassed to provide a custom implementation,
MulticastSocket, if subclassed, will still create its default implementation, even when all methods of
MulticastSocket are overridden in order not to use it. This will create a file descriptor / socket leak.
The only solution to avoid that is currently to replace the default
DatagramSocketImplFactory by calling the static
DatagramSocket.setDatagramSocketImplFactory. We need a better solution.
The solution proposed in this change is to allow DatagramSocket to both send and receive multicast datagrams. An application that need to completely replace the default multicast implementation, and that cannot be easily updated to use DatagramChannel, can do so by subclassing DatagramSocket instead.
leaveGroup(SocketAddress, NetworkInterface)up from
DatagramSocketwith an API note to describe how
DatgramSocketcan be used directly for multicasting.
- add an
@apiNoteto the various convenience getters/setters defined in
MulticastSocketto show how they map to standard socket options.
Overrides of the two methods hoisted to
DatagramSocket are kept in
MulticastSocket for the purpose of keeping
@since properly documented.
A zip of the specdiff will be attached before this CSR is finalized. In the meantime, and for convenience, the specdiff can be browsed online at:
- csr of
JDK-8237352 Update DatagramSocket to add support for joining multicast groups