added docs for wrapper query.

Closes #11591

Author: martijnvg

client/rest-high-level/src/test/java/org/elasticsearch/client/documentation/QueryDSLDocumentationTests.java

@@ -76,6 +76,7 @@
 import static org.elasticsearch.index.query.QueryBuilders.termsQuery;
 import static org.elasticsearch.index.query.QueryBuilders.typeQuery;
 import static org.elasticsearch.index.query.QueryBuilders.wildcardQuery;
+import static org.elasticsearch.index.query.QueryBuilders.wrapperQuery;
 import static org.elasticsearch.index.query.functionscore.ScoreFunctionBuilders.exponentialDecayFunction;
 import static org.elasticsearch.index.query.functionscore.ScoreFunctionBuilders.randomFunction;
 
@@ -449,4 +450,11 @@ public void testWildcard() {
                 "k?mch*");                                           // <2>
         // end::wildcard
     }
+
+    public void testWrapper() {
+        // tag::wrapper
+        String query = "{\"term\": {\"user\": \"kimchy\"}}"; // <1>
+        wrapperQuery(query);
+        // end::wrapper
+    }
 }

docs/java-api/query-dsl/special-queries.asciidoc

@@ -18,9 +18,14 @@ This query allows a script to act as a filter.  Also see the
 
 This query finds percolator queries based on documents.
 
+<<java-query-dsl-wrapper-query,`wrapper` query>>::
+
+A query that accepts other queries as json or yaml string.
+
 include::mlt-query.asciidoc[]
 
 include::script-query.asciidoc[]
 
 include::percolate-query.asciidoc[]
 
+include::wrapper-query.asciidoc[]

docs/java-api/query-dsl/wrapper-query.asciidoc

@@ -0,0 +1,11 @@
+[[java-query-dsl-wrapper-query]]
+==== Wrapper Query
+
+See {ref}/query-dsl-wrapper-query.html[Wrapper Query]
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{query-dsl-test}[wrapper]
+--------------------------------------------------
+
+<1> query defined as query builder

docs/java-rest/high-level/query-builders.asciidoc

@@ -82,6 +82,7 @@ This page lists all the available search queries with their corresponding `Query
 | {ref}/query-dsl-mlt-query.html[More Like This]                      | {query-ref}/MoreLikeThisQueryBuilder.html[MoreLikeThisQueryBuilder]                 | {query-ref}/QueryBuilders.html#moreLikeThisQuery-org.elasticsearch.index.query.MoreLikeThisQueryBuilder.Item:A-[QueryBuilders.moreLikeThisQuery()]
 | {ref}/query-dsl-script-query.html[Script]                           | {query-ref}/ScriptQueryBuilder.html[ScriptQueryBuilder]                             | {query-ref}/QueryBuilders.html#scriptQuery-org.elasticsearch.script.Script-[QueryBuilders.scriptQuery()]
 | {ref}/query-dsl-percolate-query.html[Percolate]                     | {percolate-ref}/PercolateQueryBuilder.html[PercolateQueryBuilder]                   |
+| {ref}/query-dsl-wrapper-query.html[Wrapper]                         | {query-ref}/WrapperQueryBuilder.html[WrapperQueryBuilder]                           | {query-ref}/QueryBuilders.html#wrapperQuery-java.lang.String-[QueryBuilders.wrapperQuery()]
 |======
 
 ==== Span queries

docs/reference/query-dsl/special-queries.asciidoc

@@ -19,9 +19,14 @@ This query allows a script to act as a filter.  Also see the
 This query finds queries that are stored as documents that match with
 the specified document.
 
+<<query-dsl-wrapper-query,`wrapper` query>>::
+
+A query that accepts other queries as json or yaml string.
+
 include::mlt-query.asciidoc[]
 
 include::script-query.asciidoc[]
 
 include::percolate-query.asciidoc[]
 
+include::wrapper-query.asciidoc[]

docs/reference/query-dsl/wrapper-query.asciidoc

@@ -0,0 +1,24 @@
+[[query-dsl-wrapper-query]]
+=== Wrapper Query
+
+A query that accepts any other query as base64 encoded string.
+
+[source,js]
+--------------------------------------------------
+GET /_search
+{
+    "query" : {
+        "wrapper": {
+            "query" : "eyJ0ZXJtIiA6IHsgInVzZXIiIDogIktpbWNoeSIgfX0=" <1>
+        }
+    }
+}
+--------------------------------------------------
+// CONSOLE
+
+<1> Base64 encoded string:  `{"term" : { "user" : "Kimchy" }}`
+
+This query is more useful in the context of the Java high-level REST client or
+transport client to also accept queries as json formatted string.
+In these cases queries can be specified as a json or yaml formatted string or
+as a query builder (which is a available in the Java high-level REST client).