/**
* Sets the value of response headers after making sure that the response metadata is not already
* sent.
*
* @param headerName The name of the header.
* @param headerValue The intended value of the header.
* @throws IllegalArgumentException if any of {@code headerName} or {@code headerValue} is null.
* @throws IllegalStateException if response metadata has already been written to the channel.
*/
private void setResponseHeader(String headerName, Object headerValue) {
if (headerName != null && headerValue != null) {
long startTime = System.currentTimeMillis();
if (headerValue instanceof Date) {
HttpHeaders.setDateHeader(responseMetadata, headerName, (Date) headerValue);
} else {
HttpHeaders.setHeader(responseMetadata, headerName, headerValue);
}
if (responseMetadataWritten.get()) {
nettyMetrics.deadResponseAccessError.inc();
throw new IllegalStateException(
"Response metadata changed after it has already been written to the channel");
} else {
logger.trace(
"Header {} set to {} for channel {}",
headerName,
responseMetadata.headers().get(headerName),
ctx.channel());
nettyMetrics.headerSetTimeInMs.update(System.currentTimeMillis() - startTime);
}
} else {
throw new IllegalArgumentException(
"Header name [" + headerName + "] or header value [" + headerValue + "] null");
}
}
