DefaultChannelGroup Class — netty Architecture

Source Code

transport/src/main/java/io/netty/channel/group/DefaultChannelGroup.java lines 43–463

public class DefaultChannelGroup extends AbstractSet<Channel> implements ChannelGroup {

    private static final AtomicInteger nextId = new AtomicInteger();
    private final String name;
    private final EventExecutor executor;
    private final ConcurrentMap<ChannelId, Channel> serverChannels = new ConcurrentHashMap<>();
    private final ConcurrentMap<ChannelId, Channel> nonServerChannels = new ConcurrentHashMap<>();
    private final ChannelFutureListener remover = new ChannelFutureListener() {
        @Override
        public void operationComplete(ChannelFuture future) throws Exception {
            remove(future.channel());
        }
    };
    private final VoidChannelGroupFuture voidFuture = new VoidChannelGroupFuture(this);
    private final boolean stayClosed;
    private volatile boolean closed;

    /**
     * Creates a new group with a generated name and the provided {@link EventExecutor} to notify the
     * {@link ChannelGroupFuture}s.
     */
    public DefaultChannelGroup(EventExecutor executor) {
        this(executor, false);
    }

    /**
     * Creates a new group with the specified {@code name} and {@link EventExecutor} to notify the
     * {@link ChannelGroupFuture}s.  Please note that different groups can have the same name, which means no
     * duplicate check is done against group names.
     */
    public DefaultChannelGroup(String name, EventExecutor executor) {
        this(name, executor, false);
    }

    /**
     * Creates a new group with a generated name and the provided {@link EventExecutor} to notify the
     * {@link ChannelGroupFuture}s. {@code stayClosed} defines whether or not, this group can be closed
     * more than once. Adding channels to a closed group will immediately close them, too. This makes it
     * easy, to shutdown server and child channels at once.
     */
    public DefaultChannelGroup(EventExecutor executor, boolean stayClosed) {
        this("group-0x" + Integer.toHexString(nextId.incrementAndGet()), executor, stayClosed);
    }

    /**
     * Creates a new group with the specified {@code name} and {@link EventExecutor} to notify the
     * {@link ChannelGroupFuture}s. {@code stayClosed} defines whether or not, this group can be closed
     * more than once. Adding channels to a closed group will immediately close them, too. This makes it
     * easy, to shutdown server and child channels at once. Please note that different groups can have
     * the same name, which means no duplicate check is done against group names.
     */
    public DefaultChannelGroup(String name, EventExecutor executor, boolean stayClosed) {
        ObjectUtil.checkNotNull(name, "name");
        this.name = name;
        this.executor = executor;
        this.stayClosed = stayClosed;
    }

    @Override
    public String name() {
        return name;
    }

    @Override
    public Channel find(ChannelId id) {
        Channel c = nonServerChannels.get(id);
        if (c != null) {
            return c;
        } else {
            return serverChannels.get(id);
        }
    }

    @Override
    public boolean isEmpty() {
        return nonServerChannels.isEmpty() && serverChannels.isEmpty();
    }

    @Override
    public int size() {
        return nonServerChannels.size() + serverChannels.size();