org.mortbay.jetty.nio

Class SelectChannelConnector

java.lang.Object

org.mortbay.component.AbstractLifeCycle

org.mortbay.jetty.AbstractBuffers

org.mortbay.jetty.AbstractConnector

org.mortbay.jetty.nio.AbstractNIOConnector

org.mortbay.jetty.nio.SelectChannelConnector

All Implemented Interfaces:

org.mortbay.component.LifeCycle, Buffers, Connector, NIOConnector

Direct Known Subclasses:

InheritedChannelConnector

public class SelectChannelConnector
extends AbstractNIOConnector

Selecting NIO connector.

This connector uses efficient NIO buffers with a non blocking threading model. Direct NIO buffers are used and threads are only allocated to connections with requests. Synchronization is used to simulate blocking for the servlet API, and any unflushed content at the end of request handling is written asynchronously.

This connector is best used when there are a many connections that have idle periods.

When used with Continuation, threadless waits are supported. When a filter or servlet calls getEvent on a Continuation, a RetryRequest runtime exception is thrown to allow the thread to exit the current request handling. Jetty will catch this exception and will not send a response to the client. Instead the thread is released and the Continuation is placed on the timer queue. If the Continuation timeout expires, or it's resume method is called, then the request is again allocated a thread and the request is retried. The limitation of this approach is that request content is not available on the retried request, thus if possible it should be read after the continuation or saved as a request attribute or as the associated object of the Continuation instance.

Author:

gregw

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SelectChannelConnector.ConnectorEndPoint
static class	SelectChannelConnector.RetryContinuation

Nested classes/interfaces inherited from class org.mortbay.jetty.AbstractBuffers

AbstractBuffers.ThreadBuffers

Nested classes/interfaces inherited from interface org.mortbay.component.LifeCycle

org.mortbay.component.LifeCycle.Listener

Field Summary

Fields

Modifier and Type	Field and Description
protected java.nio.channels.ServerSocketChannel	_acceptChannel

Fields inherited from class org.mortbay.jetty.AbstractConnector

_lowResourceMaxIdleTime, _maxIdleTime, _soLingerTime

Fields inherited from class org.mortbay.component.AbstractLifeCycle

_listeners

Constructor Summary

Constructors

Constructor and Description
SelectChannelConnector() Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
void	accept(int acceptorID)
void	close()
void	customize(EndPoint endpoint, Request request) Customize a request for an endpoint.
protected void	doStart()
protected void	doStop()
java.lang.Object	getConnection()
boolean	getDelaySelectKeyUpdate() Get delay select key update If true, the select set is not updated when a endpoint is dispatched for reading.
int	getLocalPort()
long	getLowResourcesConnections()
long	getLowResourcesMaxIdleTime()
protected Connection	newConnection(java.nio.channels.SocketChannel channel, SelectChannelEndPoint endpoint)
org.mortbay.util.ajax.Continuation	newContinuation()
protected SelectChannelEndPoint	newEndPoint(java.nio.channels.SocketChannel channel, SelectorManager.SelectSet selectSet, java.nio.channels.SelectionKey key)
void	open() Opens the connector
void	persist(EndPoint endpoint) Persist an endpoint.
void	setDelaySelectKeyUpdate(boolean delay)
void	setLowResourceMaxIdleTime(int lowResourcesMaxIdleTime) Set the period in ms that a connection is allowed to be idle when this there are more than getLowResourcesConnections() connections.
void	setLowResourcesConnections(long lowResourcesConnections) Set the number of connections, which if exceeded places this manager in low resources state.
void	setLowResourcesMaxIdleTime(long lowResourcesMaxIdleTime) Deprecated. use setLowResourceMaxIdleTime(int)
void	setMaxIdleTime(int maxIdleTime) Set the maximum Idle time for a connection, which roughly translates to the Socket.setSoTimeout(int) call, although with NIO implementations other mechanisms may be used to implement the timeout.

Methods inherited from class org.mortbay.jetty.nio.AbstractNIOConnector

getUseDirectBuffers, newBuffer, setUseDirectBuffers

Methods inherited from class org.mortbay.jetty.AbstractConnector

checkForwardedHeaders, configure, connectionClosed, connectionOpened, getAcceptorPriorityOffset, getAcceptors, getAcceptQueueSize, getConfidentialPort, getConfidentialScheme, getConnections, getConnectionsDurationAve, getConnectionsDurationMax, getConnectionsDurationMin, getConnectionsDurationTotal, getConnectionsOpen, getConnectionsOpenMax, getConnectionsOpenMin, getConnectionsRequestsAve, getConnectionsRequestsMax, getConnectionsRequestsMin, getForwardedForHeader, getForwardedHostHeader, getForwardedServerHeader, getHost, getHostHeader, getIntegralPort, getIntegralScheme, getLeftMostValue, getLowResourceMaxIdleTime, getMaxIdleTime, getName, getPort, getRequests, getResolveNames, getReuseAddress, getServer, getSoLingerTime, getStatsOn, getStatsOnMs, getThreadPool, isConfidential, isForwarded, isIntegral, join, setAcceptorPriorityOffset, setAcceptors, setAcceptQueueSize, setConfidentialPort, setConfidentialScheme, setForwarded, setForwardedForHeader, setForwardedHostHeader, setForwardedServerHeader, setHost, setHostHeader, setIntegralPort, setIntegralScheme, setName, setPort, setResolveNames, setReuseAddress, setServer, setSoLingerTime, setStatsOn, setThreadPool, statsReset, stopAccept, toString

Methods inherited from class org.mortbay.jetty.AbstractBuffers

getBuffer, getHeaderBufferSize, getRequestBufferSize, getResponseBufferSize, returnBuffer, setHeaderBufferSize, setRequestBufferSize, setResponseBufferSize

Methods inherited from class org.mortbay.component.AbstractLifeCycle

addLifeCycleListener, isFailed, isRunning, isStarted, isStarting, isStopped, isStopping, removeLifeCycleListener, start, stop

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.mortbay.jetty.Connector

getHeaderBufferSize, getRequestBufferSize, getResponseBufferSize, setHeaderBufferSize, setRequestBufferSize, setResponseBufferSize

Methods inherited from interface org.mortbay.component.LifeCycle

addLifeCycleListener, isFailed, isRunning, isStarted, isStarting, isStopped, isStopping, removeLifeCycleListener, start, stop

Methods inherited from interface org.mortbay.io.Buffers

getBuffer, returnBuffer

Field Detail

_acceptChannel

protected transient java.nio.channels.ServerSocketChannel _acceptChannel

Constructor Detail

SelectChannelConnector

public SelectChannelConnector()

Constructor.

Method Detail

accept

public void accept(int acceptorID)
            throws java.io.IOException

Specified by:

accept in class AbstractConnector

Throws:

java.io.IOException

close

public void close()
           throws java.io.IOException

Throws:

java.io.IOException

customize

public void customize(EndPoint endpoint,
             Request request)
               throws java.io.IOException

Description copied from interface: Connector

Customize a request for an endpoint. Called on every request to allow customization of the request for the particular endpoint (eg security properties from a SSL connection).

Specified by:

customize in interface Connector

Overrides:

customize in class AbstractConnector

Throws:

java.io.IOException

persist

public void persist(EndPoint endpoint)
             throws java.io.IOException

Description copied from interface: Connector

Persist an endpoint. Called after every request if the connection is to remain open.

Specified by:

persist in interface Connector

Overrides:

persist in class AbstractConnector

Throws:

java.io.IOException

getConnection

public java.lang.Object getConnection()

Returns:

the underlying socket, channel, buffer etc. for the connector.

getDelaySelectKeyUpdate

public boolean getDelaySelectKeyUpdate()

Get delay select key update If true, the select set is not updated when a endpoint is dispatched for reading. The assumption is that the task will be short and thus will probably be complete before the select is tried again.

Returns:

Returns the assumeShortDispatch.

getLocalPort

public int getLocalPort()

Returns:

The actual port the connector is listening on or -1 if there is no port or the connector is not open.

newContinuation

public org.mortbay.util.ajax.Continuation newContinuation()

Specified by:

newContinuation in interface Connector

Overrides:

newContinuation in class AbstractConnector

open

public void open()
          throws java.io.IOException

Description copied from interface: Connector

Opens the connector

Throws:

java.io.IOException

setDelaySelectKeyUpdate

public void setDelaySelectKeyUpdate(boolean delay)

Parameters:

delay - If true, updating a SelectionKey is delayed until a redundant event is schedules. This is an optimization that assumes event handling can be completed before the next select completes.

setMaxIdleTime

public void setMaxIdleTime(int maxIdleTime)

Description copied from class: AbstractConnector

Set the maximum Idle time for a connection, which roughly translates to the Socket.setSoTimeout(int) call, although with NIO implementations other mechanisms may be used to implement the timeout. The max idle time is applied:

• When waiting for a new request to be received on a connection
• When reading the headers and content of a request
• When writing the headers and content of a response

Jetty interprets this value as the maximum time between some progress being made on the connection. So if a single byte is read or written, then the timeout (if implemented by jetty) is reset. However, in many instances, the reading/writing is delegated to the JVM, and the semantic is more strictly enforced as the maximum time a single read/write operation can take. Note, that as Jetty supports writes of memory mapped file buffers, then a write may take many 10s of seconds for large content written to a slow device.

Previously, Jetty supported separate idle timeouts and IO operation timeouts, however the expense of changing the value of soTimeout was significant, so these timeouts were merged. With the advent of NIO, it may be possible to again differentiate these values (if there is demand).

Specified by:

setMaxIdleTime in interface Connector

Overrides:

setMaxIdleTime in class AbstractConnector

Parameters:

maxIdleTime - The maxIdleTime to set.

getLowResourcesConnections

public long getLowResourcesConnections()

Returns:

the lowResourcesConnections

setLowResourcesConnections

public void setLowResourcesConnections(long lowResourcesConnections)

Set the number of connections, which if exceeded places this manager in low resources state. This is not an exact measure as the connection count is averaged over the select sets.

Parameters:

lowResourcesConnections - the number of connections

See Also:

#setLowResourcesMaxIdleTime(long)}

getLowResourcesMaxIdleTime

public long getLowResourcesMaxIdleTime()

Returns:

the lowResourcesMaxIdleTime

setLowResourcesMaxIdleTime

public void setLowResourcesMaxIdleTime(long lowResourcesMaxIdleTime)

Deprecated. use setLowResourceMaxIdleTime(int)

Set the period in ms that a connection is allowed to be idle when this there are more than getLowResourcesConnections() connections. This allows the server to rapidly close idle connections in order to gracefully handle high load situations.

Parameters:

lowResourcesMaxIdleTime - the period in ms that a connection is allowed to be idle when resources are low.

See Also:

#setMaxIdleTime(long)}

setLowResourceMaxIdleTime

public void setLowResourceMaxIdleTime(int lowResourcesMaxIdleTime)

Set the period in ms that a connection is allowed to be idle when this there are more than getLowResourcesConnections() connections. This allows the server to rapidly close idle connections in order to gracefully handle high load situations.

Specified by:

setLowResourceMaxIdleTime in interface Connector

Overrides:

setLowResourceMaxIdleTime in class AbstractConnector

Parameters:

lowResourcesMaxIdleTime - the period in ms that a connection is allowed to be idle when resources are low.

See Also:

#setMaxIdleTime(long)}

doStart

protected void doStart()
                throws java.lang.Exception

Overrides:

doStart in class AbstractConnector

Throws:

java.lang.Exception

doStop

protected void doStop()
               throws java.lang.Exception

Overrides:

doStop in class AbstractConnector

Throws:

java.lang.Exception

newEndPoint

protected SelectChannelEndPoint newEndPoint(java.nio.channels.SocketChannel channel,
                                SelectorManager.SelectSet selectSet,
                                java.nio.channels.SelectionKey key)
                                     throws java.io.IOException

Throws:

java.io.IOException

newConnection

protected Connection newConnection(java.nio.channels.SocketChannel channel,
                       SelectChannelEndPoint endpoint)