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// Copyright 2012-present Oliver Eilhard. All rights reserved.
// Use of this source code is governed by a MIT-license.
// See http://olivere.mit-license.org/license.txt for details.
package elastic
// DisMaxQuery is a query that generates the union of documents produced by
// its subqueries, and that scores each document with the maximum score
// for that document as produced by any subquery, plus a tie breaking
// increment for any additional matching subqueries.
//
// For more details, see:
// https://www.elastic.co/guide/en/elasticsearch/reference/5.2/query-dsl-dis-max-query.html
type DisMaxQuery struct {
queries []Query
boost *float64
tieBreaker *float64
queryName string
}
// NewDisMaxQuery creates and initializes a new dis max query.
func NewDisMaxQuery() *DisMaxQuery {
return &DisMaxQuery{
queries: make([]Query, 0),
}
}
// Query adds one or more queries to the dis max query.
func (q *DisMaxQuery) Query(queries ...Query) *DisMaxQuery {
q.queries = append(q.queries, queries...)
return q
}
// Boost sets the boost for this query. Documents matching this query will
// (in addition to the normal weightings) have their score multiplied by
// the boost provided.
func (q *DisMaxQuery) Boost(boost float64) *DisMaxQuery {
q.boost = &boost
return q
}
// TieBreaker is the factor by which the score of each non-maximum disjunct
// for a document is multiplied with and added into the final score.
//
// If non-zero, the value should be small, on the order of 0.1, which says
// that 10 occurrences of word in a lower-scored field that is also in a
// higher scored field is just as good as a unique word in the lower scored
// field (i.e., one that is not in any higher scored field).
func (q *DisMaxQuery) TieBreaker(tieBreaker float64) *DisMaxQuery {
q.tieBreaker = &tieBreaker
return q
}
// QueryName sets the query name for the filter that can be used
// when searching for matched filters per hit.
func (q *DisMaxQuery) QueryName(queryName string) *DisMaxQuery {
q.queryName = queryName
return q
}
// Source returns the JSON serializable content for this query.
func (q *DisMaxQuery) Source() (interface{}, error) {
// {
// "dis_max" : {
// "tie_breaker" : 0.7,
// "boost" : 1.2,
// "queries" : {
// {
// "term" : { "age" : 34 }
// },
// {
// "term" : { "age" : 35 }
// }
// ]
// }
// }
query := make(map[string]interface{})
params := make(map[string]interface{})
query["dis_max"] = params
if q.tieBreaker != nil {
params["tie_breaker"] = *q.tieBreaker
}
if q.boost != nil {
params["boost"] = *q.boost
}
if q.queryName != "" {
params["_name"] = q.queryName
}
// queries
var clauses []interface{}
for _, subQuery := range q.queries {
src, err := subQuery.Source()
if err != nil {
return nil, err
}
clauses = append(clauses, src)
}
params["queries"] = clauses
return query, nil
}
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