4.2. Implementing WebSocket on Tomcat

You can change the write timeout in blocking mode by using the org.apache.tomcat.websocket.BLOCKING_SEND_TIMEOUT property. The property accepts values in milliseconds. The default value is 20000 milliseconds (20 seconds).

To configure incoming binary messages, MessageHandler.Partial must be defined. If MessageHandler.Partial is not defined then incoming binary messages must be buffered so that the entire message is delivered in a single call to MessageHandler.Whole.

To configure incoming text messages, MessageHandler.Partial must be defined. If MessageHandler.Partial is not defined then incoming text messages must be buffered so that the entire message is delivered in a single call to MessageHandler.Whole.

Java WebSocket specification 1.0 does not allow programmatic deployment after the first endpoint has started a WebSocket handshake. However, Tomcat by default allows additional programmatic deployment. Additional programmatic deployment can be done by using the servlet context initialization parameter org.apache.tomcat.websocket.noAddAfterHandshake.

Callbacks for asynchronous writes need to be performed on a different thread to the thread that initiated the write. The container thread pool is not exposed via the Servlet API. Hence the WebSocket implementation has to provide its own thread pool.

The timeout for IO operations while establishing the connections is controlled by userProperties of the provided javax.websocket.ClientEndpointConfig. You can change timeout by changing the org.apache.tomcat.websocket.IO_TIMEOUT_MS property. The property accepts the values in milliseconds. The default value is 5000 (5 seconds).