MemcacheClientHandler Class — netty Architecture

Source Code

example/src/main/java/io/netty/example/memcache/binary/MemcacheClientHandler.java lines 30–80

public class MemcacheClientHandler extends ChannelDuplexHandler {

    /**
     * Transforms basic string requests to binary memcache requests
     */
    @Override
    public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) {
        String command = (String) msg;
        if (command.startsWith("get ")) {
            String keyString = command.substring("get ".length());
            ByteBuf key = Unpooled.wrappedBuffer(keyString.getBytes(CharsetUtil.UTF_8));

            BinaryMemcacheRequest req = new DefaultBinaryMemcacheRequest(key);
            req.setOpcode(BinaryMemcacheOpcodes.GET);

            ctx.write(req, promise);
        } else if (command.startsWith("set ")) {
            String[] parts = command.split(" ", 3);
            if (parts.length < 3) {
                throw new IllegalArgumentException("Malformed Command: " + command);
            }
            String keyString = parts[1];
            String value = parts[2];

            ByteBuf key = Unpooled.wrappedBuffer(keyString.getBytes(CharsetUtil.UTF_8));
            ByteBuf content = Unpooled.wrappedBuffer(value.getBytes(CharsetUtil.UTF_8));
            ByteBuf extras = ctx.alloc().buffer(8);
            extras.writeZero(8);

            BinaryMemcacheRequest req = new DefaultFullBinaryMemcacheRequest(key, extras, content);
            req.setOpcode(BinaryMemcacheOpcodes.SET);

            ctx.write(req, promise);
        } else {
            throw new IllegalStateException("Unknown Message: " + msg);
        }
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) {
        FullBinaryMemcacheResponse res = (FullBinaryMemcacheResponse) msg;
        System.out.println(res.content().toString(CharsetUtil.UTF_8));
        res.release();
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        cause.printStackTrace();
        ctx.close();
    }
}