ReadListener (Java EE 8)

All Superinterfaces:

java.util.EventListener
```
public interface ReadListener
extends java.util.EventListener
```
This class represents a call-back mechanism that will notify implementations as HTTP request data becomes available to be read without blocking.

Since:

Servlet 3.1

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`onAllDataRead()`	Invoked when all data for the current request has been read.
`void`	`onDataAvailable()`	When an instance of the `ReadListener` is registered with a `ServletInputStream`, this method will be invoked by the container the first time when it is possible to read data.
`void`	`onError(java.lang.Throwable t)`	Invoked when an error occurs processing the request.

- Method Detail
  - onDataAvailable
```
void onDataAvailable()
              throws java.io.IOException
```
    When an instance of the ReadListener is registered with a ServletInputStream, this method will be invoked by the container the first time when it is possible to read data. Subsequently the container will invoke this method if and only if the ServletInputStream.isReady() method has been called and has returned a value of false and data has subsequently become available to read.
    
    Throws:
    
    java.io.IOException - if an I/O related error has occurred during processing
  - onAllDataRead
```
void onAllDataRead()
            throws java.io.IOException
```
    Invoked when all data for the current request has been read.
    
    Throws:
    
    java.io.IOException - if an I/O related error has occurred during processing
  - onError
```
void onError(java.lang.Throwable t)
```
    Invoked when an error occurs processing the request.
    
    Parameters:
    
    t - the throwable to indicate why the read operation failed