OAK-10672: move internal index version in oak-search (apache#1327)

* OAK-10672: move internal index version in oak-search

* OAK-10672: (minor) fix typos in comments

* OAK-10672: improve how the mapping version is retried from oak-search

oak-search-elastic/src/main/java/org/apache/jackrabbit/oak/plugins/index/elastic/index/ElasticIndexHelper.java

@@ -30,6 +30,7 @@
 import org.apache.jackrabbit.oak.plugins.index.elastic.ElasticIndexDefinition;
 import org.apache.jackrabbit.oak.plugins.index.elastic.ElasticPropertyDefinition;
 import org.apache.jackrabbit.oak.plugins.index.search.FieldNames;
+import org.apache.jackrabbit.oak.plugins.index.search.FulltextIndexConstants;
 import org.apache.jackrabbit.oak.plugins.index.search.PropertyDefinition;
 import org.jetbrains.annotations.NotNull;
 
@@ -52,8 +53,17 @@ class ElasticIndexHelper {
      * Changes not breaking compatibility should increment the minor version (old queries still work, but they might not
      * use the new feature).
      * Changes that do not affect queries should increment the patch version (eg: bug fixes).
+     * <p>
+     * WARN: Since this information might be needed from external tools that don't have a direct dependency on this module, the
+     * actual version needs to be set in oak-search.
      */
-    protected static final String MAPPING_VERSION = "1.1.0";
+    protected static final String MAPPING_VERSION;
+    static {
+        MAPPING_VERSION = FulltextIndexConstants.INDEX_VERSION_BY_TYPE.get(ElasticIndexDefinition.TYPE_ELASTICSEARCH);
+        if (MAPPING_VERSION == null) {
+            throw new IllegalStateException("Mapping version is not set");
+        }
+    }
 
     // Unset the refresh interval and disable replicas at index creation to optimize for initial loads
     // https://www.elastic.co/guide/en/elasticsearch/reference/current/tune-for-indexing-speed.html

oak-search/src/main/java/org/apache/jackrabbit/oak/plugins/index/search/FulltextIndexConstants.java

@@ -17,6 +17,7 @@
 package org.apache.jackrabbit.oak.plugins.index.search;
 
 import java.util.Locale;
+import java.util.Map;
 
 /**
  * Internal constants used in index definition, and index implementations.
@@ -77,7 +78,7 @@ public static IndexingMode from(String indexingMode) {
     /**
      * Type of the property being indexed defined as part of property definition
      * under the given index definition. Refer to {@link javax.jcr.PropertyType}
-     * contants for the possible values
+     * constants for the possible values
      */
     String PROP_TYPE = "type";
 
@@ -196,7 +197,7 @@ public static IndexingMode from(String indexingMode) {
 
     /**
      * Limit for maximum number of reaggregates allowed. For example if there is an aggregate of nt:folder
-     * and it also includes nt:folder then aggregation would traverse down untill this limit is hit
+     * and it also includes nt:folder then aggregation would traverse down until this limit is hit
      */
     String AGG_RECURSIVE_LIMIT = "reaggregateLimit";
 
@@ -436,4 +437,12 @@ public static IndexingMode from(String indexingMode) {
      * Boolean property indicating if in-built analyzer should preserve original term
      */
     String INDEX_ORIGINAL_TERM = "indexOriginalTerm";
+
+    /**
+     * Internal version of the index definition for specific index type. Index version is an information that might be
+     * needed from an outside process that does not have visibility to the specific index module.
+     */
+    Map<String, String> INDEX_VERSION_BY_TYPE = Map.of(
+            "elasticsearch", "1.1.0"
+    );
 }