Awesome

undertow-async

undertow-async for reactive

package io.undertow.async.pingpong;

import java.io.IOException;
import java.util.concurrent.CompletableFuture;

import io.undertow.async.handler.AsyncHttpHandler;
import io.undertow.async.io.PooledByteBufferInputStream;
import io.undertow.async.io.PooledByteBufferOutputStream;
import io.undertow.connector.ByteBufferPool;
import io.undertow.server.HttpServerExchange;
import io.undertow.util.StatusCodes;

public class PingPongAsyncHttpHandler extends AsyncHttpHandler {

    @Override
    protected void handleAsyncRequest(HttpServerExchange exchange, PooledByteBufferInputStream content)
            throws Exception {

        CompletableFuture//
                .completedFuture(content)// init
                .thenApplyAsync(this::readBytesAndClose)// read
                .thenApplyAsync(bytes -> {// write
                    ByteBufferPool byteBufferPool = exchange.getConnection().getByteBufferPool();
                    PooledByteBufferOutputStream output = new PooledByteBufferOutputStream(byteBufferPool);
                    write(output, bytes);
                    return output;
                })//
                .thenAcceptAsync(output -> send(exchange, StatusCodes.OK, output));
    }

    private byte[] readBytesAndClose(PooledByteBufferInputStream content) {
        try {
            byte[] bytes = new byte[content.available()];
            content.read(bytes);
            return bytes;
        } catch (IOException e) {
            throw new RuntimeException(e);
        } finally {
            try {// must close it
                content.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    private void write(PooledByteBufferOutputStream output, byte[] bytes) {
        try {
            output.write("asycn response: ");
            output.write(bytes);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

}