Elastic search script sort text as Number - sorting

Question

I have an Elastic search field ID which is a Number but set in the index as a "text". I cannot change the index because of the huge volume of data to reload.
I am writing a script to do this sorting but getting a "Bad_request" error.
Script script = new Script(ScriptType.INLINE, "painless", "ctx._source.ID.keyword", Collections.emptyMap());
ScriptSortBuilder.ScriptSortType sortType = ScriptSortBuilder.ScriptSortType.NUMBER;
builder.sort(SortBuilders.scriptSort(script, sortType).order(SortOrder.DESC));
searchRequest.source(builder);
response = restsearchClient.search(searchRequest, RequestOptions.DEFAULT);
I have tried the following idorcode values: doc['ID'], doc['ID.keyword'], ctx._source.ID, ctx._source.ID.keyword.
please advice!

Answer 1

If my understanding correct then you want to sort on number which is store as string and not as integer in Elasticsearch.
Below is sample Elasticsearch Query:
{
"query": {
"match_all": {}
},
"sort": {
"_script": {
"type": "Number",
"order": "desc",
"script": {
"lang": "painless",
"source": """
String s = doc['ID.keyword'].value;
int idvalue = Integer.parseInt(s);
return idvalue;
"""
}
}
}
}
Below is Java code:
Script script = new Script(ScriptType.INLINE, "painless", "String s = doc['ID.keyword'].value;int idvalue = Integer.parseInt(s);return idvalue;", Collections.emptyMap());
ScriptSortBuilder.ScriptSortType sortType = ScriptSortBuilder.ScriptSortType.NUMBER;
builder.sort(SortBuilders.scriptSort(script, sortType).order(SortOrder.DESC));