import sun.net.ExtendedOptionsImpl; //导入依赖的package包/类
private static Set<SocketOption<?>> defaultOptions() {
    HashSet<SocketOption<?>> set = new HashSet<SocketOption<?>>(8);
    set.add(StandardSocketOptions.SO_SNDBUF);
    set.add(StandardSocketOptions.SO_RCVBUF);
    set.add(StandardSocketOptions.SO_KEEPALIVE);
    set.add(StandardSocketOptions.SO_REUSEADDR);
    set.add(StandardSocketOptions.SO_LINGER);
    set.add(StandardSocketOptions.TCP_NODELAY);
    // additional options required by socket adaptor
    set.add(StandardSocketOptions.IP_TOS);
    set.add(ExtendedSocketOption.SO_OOBINLINE);
    if (ExtendedOptionsImpl.flowSupported()) {
        set.add(jdk.net.ExtendedSocketOptions.SO_FLOW_SLA);
    }
    return Collections.unmodifiableSet(set);
}
 

import sun.net.ExtendedOptionsImpl; //导入依赖的package包/类
private static Set<SocketOption<?>> defaultOptions() {
    HashSet<SocketOption<?>> set = new HashSet<SocketOption<?>>(8);
    set.add(StandardSocketOptions.SO_SNDBUF);
    set.add(StandardSocketOptions.SO_RCVBUF);
    set.add(StandardSocketOptions.SO_REUSEADDR);
    set.add(StandardSocketOptions.SO_BROADCAST);
    set.add(StandardSocketOptions.IP_TOS);
    set.add(StandardSocketOptions.IP_MULTICAST_IF);
    set.add(StandardSocketOptions.IP_MULTICAST_TTL);
    set.add(StandardSocketOptions.IP_MULTICAST_LOOP);
    if (ExtendedOptionsImpl.flowSupported()) {
        set.add(jdk.net.ExtendedSocketOptions.SO_FLOW_SLA);
    }
    return Collections.unmodifiableSet(set);
}
 

import sun.net.ExtendedOptionsImpl; //导入依赖的package包/类
static Object getSocketOption(FileDescriptor fd, ProtocolFamily family,
                              SocketOption<?> name)
    throws IOException
{
    Class<?> type = name.type();

    if (type == SocketFlow.class) {
        SecurityManager sm = System.getSecurityManager();
        if (sm != null) {
            sm.checkPermission(new NetworkPermission("getOption.SO_FLOW_SLA"));
        }
        SocketFlow flow = SocketFlow.create();
        ExtendedOptionsImpl.getFlowOption(fd, flow);
        return flow;
    }

    // only simple values supported by this method
    if (type != Integer.class && type != Boolean.class)
        throw new AssertionError("Should not reach here");

    // map option name to platform level/name
    OptionKey key = SocketOptionRegistry.findOption(name, family);
    if (key == null)
        throw new AssertionError("Option not found");

    boolean mayNeedConversion = (family == UNSPEC);
    int value = getIntOption0(fd, mayNeedConversion, key.level(), key.name());

    if (type == Integer.class) {
        return Integer.valueOf(value);
    } else {
        return (value == 0) ? Boolean.FALSE : Boolean.TRUE;
    }
}
 

import sun.net.ExtendedOptionsImpl; //导入依赖的package包/类
private static Set<SocketOption<?>> defaultOptions() {
    HashSet<SocketOption<?>> set = new HashSet<SocketOption<?>>(5);
    set.add(StandardSocketOptions.SO_SNDBUF);
    set.add(StandardSocketOptions.SO_RCVBUF);
    set.add(StandardSocketOptions.SO_KEEPALIVE);
    set.add(StandardSocketOptions.SO_REUSEADDR);
    set.add(StandardSocketOptions.TCP_NODELAY);
    if (ExtendedOptionsImpl.flowSupported()) {
        set.add(jdk.net.ExtendedSocketOptions.SO_FLOW_SLA);
    }
    return Collections.unmodifiableSet(set);
}
 

import sun.net.ExtendedOptionsImpl; //导入依赖的package包/类
private static void initOptionSets() {
    boolean flowsupported = ExtendedOptionsImpl.flowSupported();

    // Socket

    Set<SocketOption<?>> set = new HashSet<>();
    set.add(StandardSocketOptions.SO_KEEPALIVE);
    set.add(StandardSocketOptions.SO_SNDBUF);
    set.add(StandardSocketOptions.SO_RCVBUF);
    set.add(StandardSocketOptions.SO_REUSEADDR);
    set.add(StandardSocketOptions.SO_LINGER);
    set.add(StandardSocketOptions.IP_TOS);
    set.add(StandardSocketOptions.TCP_NODELAY);
    if (flowsupported) {
        set.add(ExtendedSocketOptions.SO_FLOW_SLA);
    }
    set = Collections.unmodifiableSet(set);
    options.put(Socket.class, set);

    // ServerSocket

    set = new HashSet<>();
    set.add(StandardSocketOptions.SO_RCVBUF);
    set.add(StandardSocketOptions.SO_REUSEADDR);
    set.add(StandardSocketOptions.IP_TOS);
    set = Collections.unmodifiableSet(set);
    options.put(ServerSocket.class, set);

    // DatagramSocket

    set = new HashSet<>();
    set.add(StandardSocketOptions.SO_SNDBUF);
    set.add(StandardSocketOptions.SO_RCVBUF);
    set.add(StandardSocketOptions.SO_REUSEADDR);
    set.add(StandardSocketOptions.IP_TOS);
    if (flowsupported) {
        set.add(ExtendedSocketOptions.SO_FLOW_SLA);
    }
    set = Collections.unmodifiableSet(set);
    options.put(DatagramSocket.class, set);

    // MulticastSocket

    set = new HashSet<>();
    set.add(StandardSocketOptions.SO_SNDBUF);
    set.add(StandardSocketOptions.SO_RCVBUF);
    set.add(StandardSocketOptions.SO_REUSEADDR);
    set.add(StandardSocketOptions.IP_TOS);
    set.add(StandardSocketOptions.IP_MULTICAST_IF);
    set.add(StandardSocketOptions.IP_MULTICAST_TTL);
    set.add(StandardSocketOptions.IP_MULTICAST_LOOP);
    if (flowsupported) {
        set.add(ExtendedSocketOptions.SO_FLOW_SLA);
    }
    set = Collections.unmodifiableSet(set);
    options.put(MulticastSocket.class, set);
}