org.hawkular.metrics.clients.ptrans

Class MetricBatcher

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

io.netty.handler.codec.MessageToMessageDecoder<SingleMetric>

org.hawkular.metrics.clients.ptrans.MetricBatcher

All Implemented Interfaces:

io.netty.channel.ChannelHandler, io.netty.channel.ChannelInboundHandler

public class MetricBatcher
extends io.netty.handler.codec.MessageToMessageDecoder<SingleMetric>

Batch several individual SingleMetric objects to reduce backend communication overhead.

When creating the channel pipeline, an instance of IdleStateHandler should be added just before an instance of this class. Metric batcher instances handle read IdleStateEvents.
When such an event is captured, the batch is forwarded even if the size limit is not reached. Consequently, no metric can stay in the cache several minutes before being sent to the server.

Author:

Heiko W. Rupp, Thomas Segismont

See Also:

IdleStateHandler

Nested Class Summary

Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler

io.netty.channel.ChannelHandler.Sharable

Constructor Summary

Constructors

Constructor and Description
MetricBatcher(String subKey, int minimumBatchSize) Create a batcher with the passed batch size

Method Summary

Modifier and Type	Method and Description
protected void	decode(io.netty.channel.ChannelHandlerContext ctx, SingleMetric msg, List<Object> out) Batch up incoming SingleMetric messages.
void	userEventTriggered(io.netty.channel.ChannelHandlerContext ctx, Object evt)

Methods inherited from class io.netty.handler.codec.MessageToMessageDecoder

acceptInboundMessage, channelRead

Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

channelActive, channelInactive, channelReadComplete, channelRegistered, channelUnregistered, channelWritabilityChanged, exceptionCaught

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

handlerAdded, handlerRemoved, isSharable

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.netty.channel.ChannelHandler

handlerAdded, handlerRemoved

Constructor Detail

MetricBatcher

public MetricBatcher(String subKey,
                     int minimumBatchSize)

Create a batcher with the passed batch size

Parameters:

subKey - Identification of the metrics of this batcher

minimumBatchSize - Size of batches. If the number is less than 1, then 1 is used.

Method Detail

decode

protected void decode(io.netty.channel.ChannelHandlerContext ctx,
                      SingleMetric msg,
                      List<Object> out)
               throws Exception

Batch up incoming SingleMetric messages. If the #minimumBatchSize is not yet reached, the messages are stored locally. Otherwise the list of messages will be forwarded to the next handler. This method will be called for each written message that can be handled by this encoder.

Specified by:

decode in class io.netty.handler.codec.MessageToMessageDecoder<SingleMetric>

Parameters:

ctx - the ChannelHandlerContext which this MessageToMessageDecoder belongs to

msg - the SingleMetric to be batched up

out - the List to which decoded messages should be added if the batch size is reached

Throws:

Exception - is thrown if an error occurs

userEventTriggered

public void userEventTriggered(io.netty.channel.ChannelHandlerContext ctx,
                               Object evt)
                        throws Exception

Specified by:

userEventTriggered in interface io.netty.channel.ChannelInboundHandler

Overrides:

userEventTriggered in class io.netty.channel.ChannelInboundHandlerAdapter

Throws:

Exception