Class ChannelLocal<T>

java.lang.Object

org.jboss.netty.channel.ChannelLocal<T>

All Implemented Interfaces:

Iterable<Map.Entry<Channel,T>>

public class ChannelLocal<T>
extends Object
implements Iterable<Map.Entry<Channel,T>>

A global variable that is local to a Channel. Think of this as a variation of ThreadLocal whose key is a Channel rather than a Thread.currentThread(). One difference is that you always have to specify the Channel to access the variable.

Alternatively, you might want to use the ChannelHandlerContext.attachment property, which performs better.

Field Summary

Fields

Modifier and Type	Field	Description
private final ConcurrentMap<Channel,T>	map
private final boolean	removeOnClose
private final ChannelFutureListener	remover

Constructor Summary

Constructors

Constructor	Description
ChannelLocal()	Creates a Channel local variable by calling ChannelLocal(boolean) with false as parameter
ChannelLocal(boolean removeOnClose)	Creates a Channel local variable.

Method Summary

Modifier and Type	Method	Description
T	get(Channel channel)	Returns the value of this variable.
protected T	initialValue(Channel channel)	Returns the initial value of the variable.
Iterator<Map.Entry<Channel,T>>	iterator()	Returns a read-only Iterator that holds all Map.Entry's of this ChannelLocal
T	remove(Channel channel)	Removes the variable and returns the removed value.
T	set(Channel channel, T value)	Sets the value of this variable.
T	setIfAbsent(Channel channel, T value)	Sets the value of this variable only when no value was set.

Methods inherited from class Object

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

Methods inherited from interface Iterable

forEach, spliterator

Field Details

map

private final ConcurrentMap<Channel,T> map

remover

private final ChannelFutureListener remover

removeOnClose

private final boolean removeOnClose

Constructor Details

ChannelLocal

public ChannelLocal()

Creates a Channel local variable by calling ChannelLocal(boolean) with false as parameter

ChannelLocal

public ChannelLocal(boolean removeOnClose)

Creates a Channel local variable.

Parameters:

removeOnClose - if true the ChannelLocal will remove a Channel from it own once the Channel was closed.

Method Details

initialValue

protected T initialValue(Channel channel)

Returns the initial value of the variable. By default, it returns null. Override it to change the initial value.

Parameters:

channel - the channel where this local variable is accessed with

get

public T get(Channel channel)

Returns the value of this variable.

set

public T set(Channel channel,
 T value)

Sets the value of this variable.

Returns:

the old value. null if there was no old value.

setIfAbsent

public T setIfAbsent(Channel channel,
 T value)

Sets the value of this variable only when no value was set.

Returns:

null if the specified value was set. An existing value if failed to set.

remove

public T remove(Channel channel)

Removes the variable and returns the removed value. If no value was set, this method returns the return value of initialValue(Channel), which is null by default.

Returns:

the removed value. an initial value (by default null) if no value was set.

iterator

public Iterator<Map.Entry<Channel,T>> iterator()

Returns a read-only Iterator that holds all Map.Entry's of this ChannelLocal

Specified by:

iterator in interface Iterable<T>