Package org.jboss.netty.channel

Class 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.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      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.
      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

      • removeOnClose

        private final boolean removeOnClose

    • Constructor Detail

      • 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<T>