anchor.diff:  Aggregate EIP will invoke the
   `AggregationStrategy` with `oldExchange` as null, for the first
   Exchange incoming to the aggregator. And then for
  -subsequent link:exchange.html[Exchange]s then `oldExchange` and
  +subsequent xref:exchange.adoc[Exchange]s then `oldExchange` and
   `newExchange` parameters are both not null.
   
   Example with Content Enricher EIP and no data
  
positive.code: exchanges are completed.
  * completionSize - Is a number indicating that after X aggregated
  exchanges it's complete.
  * completionPredicate - Runs a link:predicate.html[Predicate] when a new
  exchange is aggregated to determine if we are complete or not. Staring
  in *Camel 2.15*, the configured aggregationStrategy can implement the
  Predicate interface and will be used as the completionPredicate if no
  
negative.code: == Aggregate EIP
  
  The
  http://www.enterpriseintegrationpatterns.com/Aggregator.adoc[Aggregator]
  from the xref:enterprise-integration-patterns.adoc[EIP patterns] allows
  you to combine a number of messages together into a single message.
  
  image:http://www.enterpriseintegrationpatterns.com/img/Aggregator.gif[image]
  
  A correlation xref:expression.adoc[Expression] is used to determine the
  messages which should be aggregated together. If you want to aggregate
  all messages into a single message, just use a constant expression. An
  AggregationStrategy is used to combine all the message exchanges for a
  