DATAES-766 - Replace CloseableIterator with SearchHitsIterator in stream operations.

Original PR: #412

fix documentation

Author: sothawo

Diff for: src/main/asciidoc/reference/elasticsearch-misc.adoc

@@ -27,10 +27,8 @@ Page<SampleEntity> sampleEntities = operations.searchForPage(searchQuery, Sample
 [[elasticsearch.scroll]]
 == Using Scroll For Big Result Set
 
-Elasticsearch has a scroll API for getting big result set in chunks. `ElasticsearchOperations` has startScroll and continueScroll methods that can be used as below.
+Elasticsearch has a scroll API for getting big result set in chunks. This is internally used by Spring Data Elasticsearch to provide the implementations of the `<T> SearchHitsIterator<T> SearchOperations.searchForStream(Query query, Class<T> clazz, IndexCoordinates index)` method.
 
-.Using startScroll and continueScroll
-====
 [source,java]
 ----
 IndexCoordinates index = IndexCoordinates.of("sample-index");
@@ -43,25 +41,23 @@ SearchQuery searchQuery = new NativeSearchQueryBuilder()
   .withPageable(PageRequest.of(0, 10))
   .build();
 
-ScrolledPage<SampleEntity> scroll = operations.startScroll(1000, searchQuery, SampleEntity.class, index);
+SearchHitsIterator<SampleEntity> stream = elasticsearchTemplate.searchForStream(searchQuery, SampleEntity.class, index);
 
-String scrollId = scroll.getScrollId();
 List<SampleEntity> sampleEntities = new ArrayList<>();
-while (scroll.hasContent()) {
-  sampleEntities.addAll(scroll.getContent());
-  scrollId = scroll.getScrollId();
-  scroll = operations.continueScroll(scrollId, 1000, SampleEntity.class);
+while (stream.hasNext()) {
+  sampleEntities.add(stream.next());
 }
-operations.clearScroll(scrollId);
+
+stream.close();
 ----
-====
 
-`ElasticsearchOperations` additionally has the stream method which wraps the scan and scroll operations into a CloseableIterator.
+There are no methods in the `SearchOperations` API to access the scroll id, if it should be necessary to access this, the following methods of the `ElasticsearchRestTemplate` can be used:
 
-.Using stream
-====
 [source,java]
 ----
+
+@Autowired ElasticsearchRestTemplate template;
+
 IndexCoordinates index = IndexCoordinates.of("sample-index");
 
 SearchQuery searchQuery = new NativeSearchQueryBuilder()
@@ -72,14 +68,17 @@ SearchQuery searchQuery = new NativeSearchQueryBuilder()
   .withPageable(PageRequest.of(0, 10))
   .build();
 
-CloseableIterator<SampleEntity> stream = elasticsearchTemplate.stream(searchQuery, SampleEntity.class, index);
+SearchScrollHits<SampleEntity> scroll = template.searchScrollStart(1000, searchQuery, SampleEntity.class, index);
 
+String scrollId = scroll.getScrollId();
 List<SampleEntity> sampleEntities = new ArrayList<>();
-while (stream.hasNext()) {
-  sampleEntities.add(stream.next());
+while (scroll.hasSearchHits()) {
+  sampleEntities.addAll(scroll.getSearchHits());
+  scrollId = scroll.getScrollId();
+  scroll = template.searchScrollContinue(scrollId, 1000, SampleEntity.class);
 }
+template.searchScrollClear(scrollId);
 ----
-====
 
 [[elasticsearch.misc.sorts]]
 == Sort options