DefaultMessageSizeEstimator Class — netty Architecture

Source Code

transport/src/main/java/io/netty/channel/DefaultMessageSizeEstimator.java lines 27–72

public final class DefaultMessageSizeEstimator implements MessageSizeEstimator {

    private static final class HandleImpl implements Handle {
        private final int unknownSize;

        private HandleImpl(int unknownSize) {
            this.unknownSize = unknownSize;
        }

        @Override
        public int size(Object msg) {
            if (msg instanceof ByteBuf) {
                return ((ByteBuf) msg).readableBytes();
            }
            if (msg instanceof ByteBufHolder) {
                return ((ByteBufHolder) msg).content().readableBytes();
            }
            if (msg instanceof FileRegion) {
                return 0;
            }
            return unknownSize;
        }
    }

    /**
     * Return the default implementation which returns {@code 8} for unknown messages.
     */
    public static final MessageSizeEstimator DEFAULT = new DefaultMessageSizeEstimator(8);

    private final Handle handle;

    /**
     * Create a new instance
     *
     * @param unknownSize       The size which is returned for unknown messages.
     */
    public DefaultMessageSizeEstimator(int unknownSize) {
        checkPositiveOrZero(unknownSize, "unknownSize");
        handle = new HandleImpl(unknownSize);
    }

    @Override
    public Handle newHandle() {
        return handle;
    }
}