> DatagramSocket has a DatagramSocket.setDatagramSocketImplFactory method that > allows to globally replace the default DatagramSocket/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. > > Though 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 RFE is to allow DatagramSocket to both send and > receive multicast datagrams. DatagramSocket has always had the ability to > send multicast packets. In Java 15, DatagramSocket has been improved to > support getting/setting multicast options. This change proposes to move > `joinGroup(SocketAddress, NetworkInterface)` and `leaveGroup(SocketAddress, > NetworkInterface)` up from MulticastSocket into DatagramSocket. > > An application that needs to completely replace the default multicast > implementation, and that cannot be easily updated to use DatagramChannel, can > do so by subclassing DatagramSocket instead. > > In addition, this change improves the documentation of DatagramSocket and > MulticastSocket to show how convenience getters/setters map to > StandardSocketOptions, and adds an `@apiNote` to show how DatagramSocket can > be used for multicasting. > > Specdiff can be seen here: > http://cr.openjdk.java.net/~dfuchs/ds-ms-8237352-specdiff.07/overview-summary.html > > CSR: > https://bugs.openjdk.java.net/browse/JDK-8260667
Daniel Fuchs has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains ten additional commits since the last revision: - Integrated review comments. - Merge branch 'master' into ds-ms-8237352 - Integrated review comments. - Fixup @bug in the tests - Fixup @see for leaveGroup - Restore @apiNote for leaveGroup - Overrides in MulticastSocket don't need the @apiNote - 8237352: Evaluate how to write a custom DatagramSocket/MulticastSocket without using DatagramSocketImplFactory - 8237352: Evaluate how to write a custom DatagramSocket/MulticastSocket without using DatagramSocketImplFactory ------------- Changes: - all: https://git.openjdk.java.net/jdk/pull/2312/files - new: https://git.openjdk.java.net/jdk/pull/2312/files/da9a5862..83dda0b3 Webrevs: - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2312&range=05 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2312&range=04-05 Stats: 2816 lines in 110 files changed: 1459 ins; 968 del; 389 mod Patch: https://git.openjdk.java.net/jdk/pull/2312.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/2312/head:pull/2312 PR: https://git.openjdk.java.net/jdk/pull/2312
