Address code review feedback.

* Don't explicitly mention that '\0' is not allowed in keys.
* Use String#indexOf in FieldTypeLookup#fieldDepth.
* Construct the whitespace analyzer once per field mapper.

Author: jtibshirani

docs/reference/mapping/types.asciidoc

@@ -44,8 +44,6 @@ string::         <<text,`text`>> and <<keyword,`keyword`>>
 
 <<alias>>::         Defines an alias to an existing field.
 
-<<embedded-json>>:: Allows an entire JSON object to be indexed as a single field.
-
 <<rank-feature>>::  Record numeric feature to boost hits at query time.
 
 <<rank-features>>:: Record numeric features to boost hits at query time.

docs/reference/mapping/types/embedded-json.asciidoc

@@ -113,9 +113,6 @@ keyword-style aggregations such as `terms`. As with queries, there is no
 special support for numerics -- all values in the JSON object are treated as
 keywords. When sorting, this implies that values are compared lexicographically.
 
-Finally, because of the way leaf values are stored in the index, the null
-character `\0` is not allowed to appear in the keys of the JSON object.
-
 [[stored-fields]]
 ==== Stored fields
 

server/src/main/java/org/elasticsearch/index/mapper/FieldTypeLookup.java

@@ -131,15 +131,17 @@ private static int getMaxJsonFieldDepth(CopyOnWriteHashMap<String, String> alias
      */
     private static int fieldDepth(String field) {
         int numDots = 0;
-        for (int i = 0; i < field.length(); ++i) {
-            if (field.charAt(i) == '.') {
-                numDots++;
+        int dotIndex = -1;
+        while (true) {
+            dotIndex = field.indexOf('.', dotIndex + 1);
+            if (dotIndex < 0) {
+                break;
             }
+            numDots++;
         }
         return numDots + 1;
     }
 
-
     /**
      * Returns the mapped field type for the given field name.
      */

server/src/main/java/org/elasticsearch/index/mapper/JsonFieldMapper.java

@@ -89,18 +89,14 @@
  *
  * the mapper will produce untokenized string fields called "json_field" with values "some value" and "true",
  * as well as string fields called "json_field._keyed" with values "key\0some value" and "key2.key3\0true".
- *
- * Note that \0 is a reserved separator character, and cannot be used in the keys of the JSON object
- * (see {@link JsonFieldParser#SEPARATOR}).
+ * Note that \0 is used as a reserved separator character (see {@link JsonFieldParser#SEPARATOR}).
  *
  * When 'store' is enabled, a single stored field is added containing the entire JSON object in
  * pretty-printed format.
  */
 public final class JsonFieldMapper extends FieldMapper {
 
     public static final String CONTENT_TYPE = "embedded_json";
-    public static final NamedAnalyzer WHITESPACE_ANALYZER = new NamedAnalyzer(
-        "whitespace", AnalyzerScope.INDEX, new WhitespaceAnalyzer());
     private static final String KEYED_FIELD_SUFFIX = "._keyed";
 
     private static class Defaults {
@@ -183,7 +179,8 @@ public Builder copyTo(CopyTo copyTo) {
         public JsonFieldMapper build(BuilderContext context) {
             setupFieldType(context);
             if (fieldType().splitQueriesOnWhitespace()) {
-                fieldType().setSearchAnalyzer(WHITESPACE_ANALYZER);
+                NamedAnalyzer whitespaceAnalyzer = new NamedAnalyzer("whitespace", AnalyzerScope.INDEX, new WhitespaceAnalyzer());
+                fieldType().setSearchAnalyzer(whitespaceAnalyzer);
             }
             return new JsonFieldMapper(name, fieldType, defaultFieldType,
                 ignoreAbove, depthLimit, context.indexSettings());

server/src/main/java/org/elasticsearch/index/mapper/JsonFieldParser.java

@@ -138,10 +138,8 @@ private void addField(ContentPath path,
         }
 
         String key = path.pathAsText(currentName);
-        if (key.contains(SEPARATOR)) {
-            throw new IllegalArgumentException("Keys in [embedded_json] fields cannot contain the reserved character \\0."
-                + " Offending key: [" + key + "].");
-        }
+        assert key.contains(SEPARATOR) == false: "Keys in JSON fields cannot contain the reserved character \\0.";
+
         String keyedValue = createKeyedValue(key, value);
 
         if (fieldType.indexOptions() != IndexOptions.NONE) {

server/src/test/java/org/elasticsearch/index/mapper/JsonFieldMapperTests.java

@@ -488,12 +488,12 @@ public void testSplitQueriesOnWhitespace() throws IOException {
         mapperService.merge("type", new CompressedXContent(mapping), MapperService.MergeReason.MAPPING_UPDATE);
 
         RootJsonFieldType rootFieldType = (RootJsonFieldType) mapperService.fullName("field");
-        assertThat(rootFieldType.searchAnalyzer(), equalTo(JsonFieldMapper.WHITESPACE_ANALYZER));
+        assertThat(rootFieldType.searchAnalyzer().name(), equalTo("whitespace"));
         assertTokenStreamContents(rootFieldType.searchAnalyzer().analyzer().tokenStream("", "Hello World"),
             new String[] {"Hello", "World"});
 
         KeyedJsonFieldType keyedFieldType = (KeyedJsonFieldType) mapperService.fullName("field.key");
-        assertThat(keyedFieldType.searchAnalyzer(), equalTo(JsonFieldMapper.WHITESPACE_ANALYZER));
+        assertThat(keyedFieldType.searchAnalyzer().name(), equalTo("whitespace"));
         assertTokenStreamContents(keyedFieldType.searchAnalyzer().analyzer().tokenStream("", "Hello World"),
             new String[] {"Hello", "World"});
     }