WriteListener (Servlet 4.0 API Documentation - Apache Tomcat 9.0.120)
Description: declaration: package: javax.servlet, interface: WriteListener

# Interface WriteListener

All Superinterfaces:
  `EventListener`

public interface WriteListener extends EventListener
Receives notification of write events when using non-blocking IO.

Since:
  Servlet 3.1

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `onError(Throwable throwable)`
  Invoked if an error occurs while writing the response.
  `void`
  `onWritePossible()`
  Invoked when it it possible to write data without blocking.

- ## Method Details

  - ### onWritePossible

    void onWritePossible() throws IOException
    Invoked when it it possible to write data without blocking. The container will invoke this method the first time for a request as soon as data can be written. Subsequent invocations will only occur if a call to `ServletOutputStream.isReady()` has returned false and it has since become possible to write data.
    Throws:
      `IOException` - if an I/O error occurs while processing this event

  - ### onError

    void onError(Throwable throwable)
    Invoked if an error occurs while writing the response.
    Parameters:
      `throwable` - The throwable that represents the error that occurred