UpgradeServletOutputStream (Apache Tomcat 9.0.120 API Documentation)
Description: declaration: package: org.apache.coyote.http11.upgrade, class: UpgradeServletOutputStream

# Class UpgradeServletOutputStream

java.lang.Object
java.io.OutputStream
javax.servlet.ServletOutputStream
org.apache.coyote.http11.upgrade.UpgradeServletOutputStream

All Implemented Interfaces:
  `Closeable, Flushable, AutoCloseable`

public class UpgradeServletOutputStream extends ServletOutputStream
Output stream for an HTTP upgraded connection.

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `UpgradeServletOutputStream(UpgradeProcessorBase processor, SocketWrapperBase<?> socketWrapper, UpgradeInfo upgradeInfo)`
  Constructs a new UpgradeServletOutputStream.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `close()`
  `void`
  `flush()`
  `final boolean`
  `isReady()`
  Checks if a non-blocking write will succeed.
  `final void`
  `setWriteListener(WriteListener listener)`
  Sets the `WriteListener` for this `ServletOutputStream` and thereby switches to non-blocking IO.
  `void`
  `write(byte[] b, int off, int len)`
  `void`
  `write(int b)`

  ### Methods inherited from class ServletOutputStream

  `print, print, print, print, print, print, print, println, println, println, println, println, println, println, println`

  ### Methods inherited from class OutputStream

  `nullOutputStream, write`

  ### Methods inherited from class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Constructor Details

  - ### UpgradeServletOutputStream

    public UpgradeServletOutputStream(UpgradeProcessorBase processor, SocketWrapperBase<?> socketWrapper, UpgradeInfo upgradeInfo)
    Constructs a new UpgradeServletOutputStream.
    Parameters:
      `processor` - the processor
      `socketWrapper` - the socket wrapper
      `upgradeInfo` - the statistics object

- ## Method Details

  - ### isReady

    public final boolean isReady()
    Description copied from class: `javax.servlet.ServletOutputStream`
    Checks if a non-blocking write will succeed. If this returns `false`, it will cause a callback to `WriteListener.onWritePossible()` when the buffer has emptied. If this method returns `false` no further data must be written until the container calls `WriteListener.onWritePossible()`.
    Specified by:
      `isReady` in class `ServletOutputStream`
    Returns:
      `true` if data can be written, else `false`

  - ### setWriteListener

    public final void setWriteListener(WriteListener listener)
    Description copied from class: `javax.servlet.ServletOutputStream`
    Sets the `WriteListener` for this `ServletOutputStream` and thereby switches to non-blocking IO. It is only valid to switch to non-blocking IO within async processing or HTTP upgrade processing.
    Specified by:
      `setWriteListener` in class `ServletOutputStream`
    Parameters:
      `listener` - The non-blocking IO write listener

  - ### write

    public void write(int b) throws IOException
    Specified by:
      `write` in class `OutputStream`
    Throws:
      `IOException`

  - ### write

    public void write(byte[] b, int off, int len) throws IOException
    Overrides:
      `write` in class `OutputStream`
    Throws:
      `IOException`

  - ### flush

    public void flush() throws IOException
    Specified by:
      `flush` in interface `Flushable`
    Overrides:
      `flush` in class `OutputStream`
    Throws:
      `IOException`

  - ### close

    public void close() throws IOException
    Specified by:
      `close` in interface `AutoCloseable`
    Specified by:
      `close` in interface `Closeable`
    Overrides:
      `close` in class `OutputStream`
    Throws:
      `IOException`