io.reactivex.netty.channel

Class AllocatingTransformer<T,TT>

java.lang.Object

io.reactivex.netty.channel.AllocatingTransformer<T,TT>

Type Parameters:

T - Source type.

TT - Target type.

@Beta
public abstract class AllocatingTransformer<T,TT>
extends java.lang.Object

A transformer to be used for modifying the type of objects written on a Connection.

Why is this required?

The type of an object can usually be transformed using Observable.map(), however, while writing on a Connection, typically one requires to allocate buffers. Although a Connection provides a way to retrieve the ByteBufAllocator via the Channel, allocating buffers from outside the eventloop will lead to buffer bloats as the allocators will typically use thread-local buffer pools.

This transformer is always invoked from within the eventloop and hence does not have buffer bloating issues, even when transformations happen outside the eventloop.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AllocatingTransformer()

Method Summary

Modifier and Type	Method and Description
protected boolean	acceptMessage(java.lang.Object msg) Asserts whether the passed message can be transformed using this transformer.
abstract java.util.List<TT>	transform(T toTransform, io.netty.buffer.ByteBufAllocator allocator) Transforms the passed message and adds the output to the returned list.

Methods inherited from class java.lang.Object

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

Constructor Detail

AllocatingTransformer

protected AllocatingTransformer()

Method Detail

acceptMessage

protected boolean acceptMessage(java.lang.Object msg)

Asserts whether the passed message can be transformed using this transformer.

Parameters:

msg - Message to transform.

Returns:

true if the message can be transformed.

transform

public abstract java.util.List<TT> transform(T toTransform,
                                             io.netty.buffer.ByteBufAllocator allocator)

Transforms the passed message and adds the output to the returned list.

Parameters:

toTransform - Message to transform.

allocator - Allocating for allocating buffers, if required.

Returns:

Output of the transformation.