PrefixQueryParser takes a String as value like its Builder

Relates #12032
Closes #12204

Author: alexksikes

core/src/main/java/org/elasticsearch/index/mapper/MappedFieldType.java

@@ -460,7 +460,7 @@ public Query fuzzyQuery(Object value, Fuzziness fuzziness, int prefixLength, int
         return new FuzzyQuery(createTerm(value), fuzziness.asDistance(BytesRefs.toString(value)), prefixLength, maxExpansions, transpositions);
     }
 
-    public Query prefixQuery(Object value, @Nullable MultiTermQuery.RewriteMethod method, @Nullable QueryParseContext context) {
+    public Query prefixQuery(String value, @Nullable MultiTermQuery.RewriteMethod method, @Nullable QueryParseContext context) {
         PrefixQuery query = new PrefixQuery(createTerm(value));
         if (method != null) {
             query.setRewriteMethod(method);

core/src/main/java/org/elasticsearch/index/mapper/internal/IdFieldMapper.java

@@ -184,7 +184,7 @@ public Query termsQuery(List values, @Nullable QueryParseContext context) {
         }
 
         @Override
-        public Query prefixQuery(Object value, @Nullable MultiTermQuery.RewriteMethod method, @Nullable QueryParseContext context) {
+        public Query prefixQuery(String value, @Nullable MultiTermQuery.RewriteMethod method, @Nullable QueryParseContext context) {
             if (indexOptions() != IndexOptions.NONE || context == null) {
                 return super.prefixQuery(value, method, context);
             }

core/src/main/java/org/elasticsearch/index/query/PrefixQueryParser.java

@@ -55,7 +55,7 @@ public Query parse(QueryParseContext parseContext) throws IOException, QueryPars
         String rewriteMethod = null;
         String queryName = null;
 
-        Object value = null;
+        String value = null;
         float boost = 1.0f;
         String currentFieldName = null;
         XContentParser.Token token;
@@ -73,7 +73,7 @@ public Query parse(QueryParseContext parseContext) throws IOException, QueryPars
                         if ("_name".equals(currentFieldName)) {
                             queryName = parser.text();
                         } else if ("value".equals(currentFieldName) || "prefix".equals(currentFieldName)) {
-                            value = parser.objectBytes();
+                            value = parser.textOrNull();
                         } else if ("boost".equals(currentFieldName)) {
                             boost = parser.floatValue();
                         } else if ("rewrite".equals(currentFieldName)) {
@@ -88,7 +88,7 @@ public Query parse(QueryParseContext parseContext) throws IOException, QueryPars
                     queryName = parser.text();
                 } else {
                     fieldName = currentFieldName;
-                    value = parser.objectBytes();
+                    value = parser.textOrNull();
                 }
             }
         }