org.jboss.netty.channel

Class ChannelLocal<T>

java.lang.Object

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

All Implemented Interfaces:

java.lang.Iterable<java.util.Map.Entry<Channel,T>>

public class ChannelLocal<T>
extends java.lang.Object
implements java.lang.Iterable<java.util.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 and Description
private java.util.concurrent.ConcurrentMap<Channel,T>	map
private boolean	removeOnClose
private ChannelFutureListener	remover

Constructor Summary

Constructors

Constructor and 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 and Description
T	get(Channel channel) Returns the value of this variable.
protected T	initialValue(Channel channel) Returns the initial value of the variable.
java.util.Iterator<java.util.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 java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

map

private final java.util.concurrent.ConcurrentMap<Channel,T> map

remover

private final ChannelFutureListener remover

removeOnClose

private final boolean removeOnClose

Constructor Detail

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 Detail

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

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

Specified by:

iterator in interface java.lang.Iterable<java.util.Map.Entry<Channel,T>>