Custom plugin for search

[toloo]

Hello,

I'm new to Elasticsearch. I'm looking to write a plugin that at search time, it only looks at some specific sub-fields based on the search query. For example, with the following example I only want to get "Cat Fred" as the result by only looking at text.Cat subfield. I cloned the source code and implemented this behavior by changing the fromXContent method in MultiMatchQueryBuilder.java. Can someone help me how I can override this method somehow in a plugin?

Example:

PUT my_index
{
  "mappings": {
    "properties": {
      "text": { 
        "type": "text",
        "fields": {
          "Dog": {
            "type": "text",
            "analyzer": "english"
          },
          "Cat": {
            "type": "text",
            "analyzer": "english"
          }
        }
      }
    }
  }
}


PUT my_index/_doc/1
{
  "text" : "Cat Fred"
}

PUT my_index/_doc/2
{
  "text" : "Dog Fred"
}

GET my_index/_search
{
  "query": {
    "multi_match": {
      "query": "Fred",
    }
  }
}