Package org.eclipse.jetty.io

Class WriteFlusher

java.lang.Object

org.eclipse.jetty.io.WriteFlusher

public abstract class WriteFlusher
extends java.lang.Object

A Utility class to help implement EndPoint.write(Callback, ByteBuffer...) by calling EndPoint.flush(ByteBuffer...) until all content is written. The abstract method onIncompleteFlush() is called when not all content has been written after a call to flush and should organize for the completeWrite() method to be called when a subsequent call to flush should be able to make more progress.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	WriteFlusher.CompletingState	In CompletingState WriteFlusher is flushing buffers that have not been fully written in write().
private static class	WriteFlusher.FailedState	In FailedState no more operations are allowed.
private static class	WriteFlusher.IdleState	In IdleState WriteFlusher is idle and accepts new writes
static interface	WriteFlusher.Listener	A listener of WriteFlusher events.
private class	WriteFlusher.PendingState	In PendingState not all buffers could be written in one go.
private static class	WriteFlusher.State	State represents a State of WriteFlusher.
private static class	WriteFlusher.StateType
private static class	WriteFlusher.WritingState	In WritingState WriteFlusher is currently writing.

Field Summary

Fields

Modifier and Type	Field	Description
private static WriteFlusher.State	__COMPLETING
private static WriteFlusher.State	__IDLE
private static java.util.EnumMap<WriteFlusher.StateType,java.util.Set<WriteFlusher.StateType>>	__stateTransitions
private static WriteFlusher.State	__WRITING
private EndPoint	_endPoint
private java.util.concurrent.atomic.AtomicReference<WriteFlusher.State>	_state
private static boolean	DEBUG
private static java.nio.ByteBuffer[]	EMPTY_BUFFERS
private static Logger	LOG

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	WriteFlusher(EndPoint endPoint)

Method Summary

Modifier and Type	Method	Description
void	completeWrite()	Complete a write that has not completed and that called onIncompleteFlush() to request a call to this method when a call to EndPoint.flush(ByteBuffer...) is likely to be able to progress.
private void	fail(Callback callback, java.lang.Throwable... suppressed)
protected java.nio.ByteBuffer[]	flush(java.nio.ByteBuffer[] buffers)	Flushes the buffers iteratively until no progress is made.
Invocable.InvocationType	getCallbackInvocationType()
(package private) boolean	isFailed()
(package private) boolean	isIdle()
boolean	isPending()
private boolean	isState(WriteFlusher.StateType type)
private boolean	isTransitionAllowed(WriteFlusher.State currentState, WriteFlusher.State newState)
void	onClose()
boolean	onFail(java.lang.Throwable cause)	Notify the flusher of a failure
protected abstract void	onIncompleteFlush()	Abstract call to be implemented by specific WriteFlushers.
java.lang.String	toStateString()
java.lang.String	toString()
private boolean	updateState(WriteFlusher.State previous, WriteFlusher.State next)	Tries to update the current state to the given new state.
void	write(Callback callback, java.nio.ByteBuffer... buffers)	Tries to switch state to WRITING.

Methods inherited from class java.lang.Object

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

Field Detail

LOG

private static final Logger LOG

DEBUG

private static final boolean DEBUG

EMPTY_BUFFERS

private static final java.nio.ByteBuffer[] EMPTY_BUFFERS

__stateTransitions

private static final java.util.EnumMap<WriteFlusher.StateType,java.util.Set<WriteFlusher.StateType>> __stateTransitions

__IDLE

private static final WriteFlusher.State __IDLE

__WRITING

private static final WriteFlusher.State __WRITING

__COMPLETING

private static final WriteFlusher.State __COMPLETING

_endPoint

private final EndPoint _endPoint

_state

private final java.util.concurrent.atomic.AtomicReference<WriteFlusher.State> _state

Constructor Detail

WriteFlusher

protected WriteFlusher(EndPoint endPoint)

Method Detail

updateState

private boolean updateState(WriteFlusher.State previous,
                            WriteFlusher.State next)

Tries to update the current state to the given new state.

Parameters:

previous - the expected current state

next - the desired new state

Returns:

the previous state or null if the state transition failed

Throws:

java.nio.channels.WritePendingException - if currentState is WRITING and new state is WRITING (api usage error)

isTransitionAllowed

private boolean isTransitionAllowed(WriteFlusher.State currentState,
                                    WriteFlusher.State newState)

getCallbackInvocationType

public Invocable.InvocationType getCallbackInvocationType()

onIncompleteFlush

protected abstract void onIncompleteFlush()

Abstract call to be implemented by specific WriteFlushers. It should schedule a call to completeWrite() or onFail(Throwable) when appropriate.

write

public void write(Callback callback,
                  java.nio.ByteBuffer... buffers)
           throws java.nio.channels.WritePendingException

Tries to switch state to WRITING. If successful it writes the given buffers to the EndPoint. If state transition fails it will fail the callback and leave the WriteFlusher in a terminal FAILED state. If not all buffers can be written in one go it creates a new PendingState object to preserve the state and then calls onIncompleteFlush(). The remaining buffers will be written in completeWrite(). If all buffers have been written it calls callback.complete().

Parameters:

callback - the callback to call on either failed or complete

buffers - the buffers to flush to the endpoint

Throws:

java.nio.channels.WritePendingException - if unable to write due to prior pending write

fail

private void fail(Callback callback,
                  java.lang.Throwable... suppressed)

completeWrite

public void completeWrite()

Complete a write that has not completed and that called onIncompleteFlush() to request a call to this method when a call to EndPoint.flush(ByteBuffer...) is likely to be able to progress. It tries to switch from PENDING to COMPLETING. If state transition fails, then it does nothing as the callback should have been already failed. That's because the only way to switch from PENDING outside this method is onFail(Throwable) or onClose()

flush

protected java.nio.ByteBuffer[] flush(java.nio.ByteBuffer[] buffers)
                               throws java.io.IOException

Flushes the buffers iteratively until no progress is made.

Parameters:

buffers - The buffers to flush

Returns:

The unflushed buffers, or null if all flushed

Throws:

java.io.IOException - if unable to flush

onFail

public boolean onFail(java.lang.Throwable cause)

Notify the flusher of a failure

Parameters:

cause - The cause of the failure

Returns:

true if the flusher passed the failure to a Callback instance

onClose

public void onClose()

isFailed

boolean isFailed()

isIdle

boolean isIdle()

isPending

public boolean isPending()

isState

private boolean isState(WriteFlusher.StateType type)

toStateString

public java.lang.String toStateString()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object