Pattern Tokenizer for extracting file name

Question

I want to tokenize "a.b.c" into a, a.b, a.b.c, b.c, b, c parts in ElasticSearch. I tried some regex but updating tokenizer is tedious and I'm very bad at regex so I'm asking for help.

I already tried this formulas but they didn't gave me what I want:

[(^\\.)]+
[(.+\\.)]+
[^\\p{L}\\d]+

Answer 1

Try this,

PUT my_sample
{
  "settings": {
    "analysis": {
      "analyzer": {
        "my_analyzer": {
          "tokenizer": "my_tokenizer"
        }
      },
      "tokenizer": {
        "my_tokenizer": {
          "type": "path_hierarchy",
          "delimiter": ".",
          "replacement": "."
        }
      }
    }
  }
}

then,

POST my_sample/_analyze
{
  "analyzer": "my_analyzer",
  "text": "a.b.c"
}

it will produces the following terms:

[ a.b.c., a.b., b.c., a., b., c. ]

then you simple handle it through your program