private void sendAsyncResponse()

in modules/transports/core/nhttp/src/main/java/org/apache/synapse/transport/nhttp/HttpCoreNIOSender.java [443:560]
100 lines of code
31 McCabe index (conditional complexity)

    private void sendAsyncResponse(MessageContext msgContext) throws AxisFault {

        int contentLength = extractContentLength(msgContext);

        // remove unwanted HTTP headers (if any from the current message)
        removeUnwantedHeaders(msgContext);

        ServerWorker worker = (ServerWorker) msgContext.getProperty(Constants.OUT_TRANSPORT_INFO);
        HttpResponse response = worker.getResponse();

        OMOutputFormat format = NhttpUtil.getOMOutputFormat(msgContext);
        MessageFormatter messageFormatter =
                MessageFormatterDecoratorFactory.createMessageFormatterDecorator(msgContext);
        Boolean noEntityBody = (Boolean) msgContext.getProperty(NhttpConstants.NO_ENTITY_BODY);
        if (noEntityBody == null || Boolean.FALSE == noEntityBody) {
            response.setHeader(
                HTTP.CONTENT_TYPE,
                messageFormatter.getContentType(msgContext, format, msgContext.getSoapAction()));
        } else if ( Boolean.TRUE == noEntityBody) {
            ((BasicHttpEntity)response.getEntity()).setChunked(false);
            ((BasicHttpEntity)response.getEntity()).setContentLength(0);
        }
        response.setStatusCode(determineHttpStatusCode(msgContext, response));

        // set any transport headers
        Map transportHeaders = (Map) msgContext.getProperty(MessageContext.TRANSPORT_HEADERS);
        if (transportHeaders != null && !transportHeaders.values().isEmpty()) {
            Iterator iter = transportHeaders.keySet().iterator();
            while (iter.hasNext()) {
                Object header = iter.next();
                Object value = transportHeaders.get(header);
                if (value != null && header instanceof String && value instanceof String) {
                    response.setHeader((String) header, (String) value);
                }
            }
        }

        boolean forceContentLength = msgContext.isPropertyTrue(
                NhttpConstants.FORCE_HTTP_CONTENT_LENGTH);
        boolean forceContentLengthCopy = msgContext.isPropertyTrue(
                NhttpConstants.COPY_CONTENT_LENGTH_FROM_INCOMING);

        BasicHttpEntity entity = (BasicHttpEntity) response.getEntity();

        MetricsCollector lstMetrics = worker.getServiceHandler().getMetrics();
        try {
            if (forceContentLength) {
                entity.setChunked(false);
                if (forceContentLengthCopy && contentLength > 0) {
                    entity.setContentLength(contentLength);
                } else {
                    setStreamAsTempData(entity, messageFormatter, msgContext, format);
                }
            }

            worker.getServiceHandler().commitResponse(worker.getConn(), response);
            if (lstMetrics != null) {
                lstMetrics.reportResponseCode(response.getStatusLine().getStatusCode());
            }
            OutputStream out = worker.getOutputStream();

            /*
             * if this is a dummy message to handle http 202 case with non-blocking IO
             * write an empty byte array as body
             */
            if (msgContext.isPropertyTrue(NhttpConstants.SC_ACCEPTED)
                || Boolean.TRUE == noEntityBody) {
                out.write(new byte[0]);
            } else {
                if (forceContentLength) {
                    if (forceContentLengthCopy && contentLength > 0) {
                        messageFormatter.writeTo(msgContext, format, out, false);
                    } else {
                        writeMessageFromTempData(out, msgContext);
                    }
                } else {
                    messageFormatter.writeTo(msgContext, format, out, false);
                }
            }
            out.close();
            if (lstMetrics != null) {
                lstMetrics.incrementMessagesSent();
            }

        } catch (ProtocolException e) {
            log.error(e + " (Synapse may be trying to send an exact response more than once )");
        } catch (HttpException e) {
            if (lstMetrics != null) {
                lstMetrics.incrementFaultsSending();
            }
            handleException("Unexpected HTTP protocol error sending response to : " +
                worker.getRemoteAddress(), e);
        } catch (ConnectionClosedException e) {
            if (lstMetrics != null) {
                lstMetrics.incrementFaultsSending();
            }
            log.warn("Connection closed by client : " + worker.getRemoteAddress());
        } catch (IOException e) {
            if (lstMetrics != null) {
                lstMetrics.incrementFaultsSending();
            }
            handleException("IO Error sending response message to : " +
                worker.getRemoteAddress(), e);
        } catch (Exception e) {
            if (lstMetrics != null) {
                lstMetrics.incrementFaultsSending();
            }
            handleException("General Error sending response message to : " +
                worker.getRemoteAddress(), e);
        }

        InputStream is = worker.getIs();
        if (is != null) {
            try {
                is.close();
            } catch (IOException ignore) {}
        }
    }