flat multiple nested fields

Signed-off-by: Mingshi Liu <[email protected]>

plugins/flat-object/src/main/java/org/opensearch/flatobject/xcontent/KeyValueJsonXContentParser.java

@@ -8,6 +8,7 @@
 
 package org.opensearch.flatobject.xcontent;
 
+import com.fasterxml.jackson.core.JsonParser;
 import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.xcontent.DeprecationHandler;
 import org.opensearch.common.xcontent.NamedXContentRegistry;
@@ -51,30 +52,52 @@ public KeyValueJsonXContentParser(
  }
 
  public XContentParser parseObject() throws IOException {
- String currentFieldName = null;
  builder.startObject();
- while (this.parser.nextToken() != Token.END_OBJECT) {
- currentFieldName = this.parser.currentName();
- logger.info("currentFieldName: " + currentFieldName + "\n");
- this.parser.nextToken();
- StringBuilder parsedFields = new StringBuilder();
- parseValue(currentFieldName, parsedFields);
- builder.field(currentFieldName + "_path", currentFieldName);
- builder.field(currentFieldName + "_value", parsedFields.toString());
- }
-
+ parseToken();
  builder.endObject();
  String jString = XContentHelper.convertToJson(BytesReference.bytes(builder), false, XContentType.JSON);
  logger.info("Before createParser, jString: " + jString + "\n");
 
  return JsonXContent.jsonXContent.createParser(this.xContentRegistry, this.deprecationHandler, String.valueOf(jString));
  }
 
+ private void parseToken() throws IOException {
+ String currentFieldName;
+ while (this.parser.nextToken() != Token.END_OBJECT) {
+
+ currentFieldName = this.parser.currentName();
+
+ logger.info("currentFieldName: " + currentFieldName + "\n");
+ StringBuilder parsedFields = new StringBuilder();
+ if (this.parser.nextToken() == Token.START_OBJECT){
+ /**
+ * for nested Json, make a copy of parser, then parse the entire Json as string.
+ * for example:
+ * {"grandpa": {
+ * "dad": {
+ * "son": "me"
+ * } }
+ * the flat field for "grandpa" would be {"grandpa_path": "grandpa", "grandpa_value"= "{"dad: {"son": "me"}"}"}
+ */
+ //To do. to convert the entire JsonObject without changing the tokenizer position.
+ parsedFields.append(this.parser.toString() );
+// parsedFields.append(this.parser.mapOrdered().toString() );
+ builder.field(currentFieldName + "_path", currentFieldName);
+ builder.field(currentFieldName + "_value", parsedFields.toString());
+ parseToken();
+ }
+ else{
+ parseValue(currentFieldName, parsedFields);
+ builder.field(currentFieldName + "_path", currentFieldName);
+ builder.field(currentFieldName + "_value", parsedFields.toString());
+ }
+
+ }
+ }
+
  private void parseValue(String currentFieldName, StringBuilder parsedFields) throws IOException {
+ logger.info("this.parser.currentToken(): " + this.parser.currentToken() + "\n");
  switch (this.parser.currentToken()) {
- case START_OBJECT:
- parseObject();
- break;
  case VALUE_STRING:
  /**
  * this is "value" only format for each subfield
@@ -84,6 +107,16 @@ private void parseValue(String currentFieldName, StringBuilder parsedFields) thr
  logger.info("currentFieldName and parsedFields :" + currentFieldName + " " + parsedFields.toString() + "\n");
  break;
  // Handle other token types as needed
+ // ToDo, what do we do, if encountered these fields?
+ // should never gets to START_OBJECT
+ case START_OBJECT:
+ throw new IOException("Unsupported token type");
+ case FIELD_NAME:
+ logger.info("token is FIELD_NAME: " + this.parser.currentName() + "\n");
+ break;
+ case VALUE_EMBEDDED_OBJECT:
+ logger.info("token is VALUE_EMBEDDED_OBJECT: " + this.parser.objectText()+ "\n");
+ break;
  default:
  throw new IOException("Unsupported token type [" + parser.currentToken() + "]");
  }