WriteListener (Java Servlet 4.0)

All Superinterfaces:

EventListener
```
public interface WriteListener
extends EventListener
```
Callback notification mechanism that signals to the developer it's possible to write content without blocking.

Since:

Servlet 3.1

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`onError(Throwable t)`	Invoked when an error occurs writing data using the non-blocking APIs.
`void`	`onWritePossible()`	When an instance of the WriteListener is registered with a `ServletOutputStream`, this method will be invoked by the container the first time when it is possible to write data.

- Method Detail
  - onWritePossible
```
void onWritePossible()
              throws IOException
```
    When an instance of the WriteListener is registered with a ServletOutputStream, this method will be invoked by the container the first time when it is possible to write data. Subsequently the container will invoke this method if and only if the ServletOutputStream.isReady() method has been called and has returned a value of false and a write operation has subsequently become possible.
    
    Throws:
    
    IOException - if an I/O related error has occurred during processing
  - onError
```
void onError(Throwable t)
```
    Invoked when an error occurs writing data using the non-blocking APIs.
    
    Parameters:
    
    t - the throwable to indicate why the write operation failed