From f331658e76e8315a2ff78eec20137a836e8848f0 Mon Sep 17 00:00:00 2001
From: Hendrik Muhs <hendrik.muhs@elastic.co>
Date: Wed, 17 Oct 2018 19:45:30 +0200
Subject: [PATCH] add some documentation/notes on inner design

---
 .../job/FeatureIndexBuilderIndexer.java                    | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/x-pack/plugin/ml-feature-index-builder/src/main/java/org/elasticsearch/xpack/ml/featureindexbuilder/job/FeatureIndexBuilderIndexer.java b/x-pack/plugin/ml-feature-index-builder/src/main/java/org/elasticsearch/xpack/ml/featureindexbuilder/job/FeatureIndexBuilderIndexer.java
index 1725ef3f711c9..1fc22c828042e 100644
--- a/x-pack/plugin/ml-feature-index-builder/src/main/java/org/elasticsearch/xpack/ml/featureindexbuilder/job/FeatureIndexBuilderIndexer.java
+++ b/x-pack/plugin/ml-feature-index-builder/src/main/java/org/elasticsearch/xpack/ml/featureindexbuilder/job/FeatureIndexBuilderIndexer.java
@@ -64,7 +64,12 @@ protected IterationResult<Map<String, Object>> doProcess(SearchResponse searchRe
     }
 
     /*
-     * Parses the result and creates indexable documents
+     * Parses the result and creates a stream of indexable documents
+     *
+     * Implementation decisions:
+     *
+     * Extraction uses generic maps as intermediate exchange format in order to hook in ingest pipelines/processors
+     * in later versions, see {@link IngestDocument).
      */
     private Stream<IndexRequest> processBucketsToIndexRequests(CompositeAggregation agg) {
         String indexName = job.getConfig().getDestinationIndex();