commonMain.operations.CountOperations.kt Maven / Gradle / Ivy
/*
* Copyright (c) 2024, OpenSavvy and contributors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package opensavvy.ktmongo.sync.operations
import opensavvy.ktmongo.dsl.expr.FilterOperators
import opensavvy.ktmongo.dsl.options.CountOptions
/**
* Interface grouping MongoDB operations relating to counting documents.
*/
interface CountOperations : BaseOperations {
/**
* Counts how many documents exist in the collection.
*
* ### External resources
*
* - [Official documentation](https://www.mongodb.com/docs/manual/reference/method/db.collection.countDocuments/)
*
* @see countEstimated Faster alternative when the result doesn't need to be exact.
*/
fun count(): Long
/**
* Counts how many documents match [predicate] in the collection.
*
* ### Example
*
* ```kotlin
* class User(
* val name: String,
* val age: Int,
* )
*
* collection.count {
* User::name eq "foo"
* User::age eq 10
* }
* ```
*
* ### External resources
*
* - [Official documentation](https://www.mongodb.com/docs/manual/reference/method/db.collection.countDocuments/)
*/
fun count(
options: CountOptions.() -> Unit = {},
predicate: FilterOperators.() -> Unit
): Long
/**
* Counts all documents in the collection.
*
* This function reads collection metadata instead of actually counting through all documents.
* This makes it much more performant (almost no CPU nor RAM usage), but the count may be slightly out of date.
*
* In particular, it may become inaccurate when:
* - there are orphaned documents in a shared cluster,
* - an unclean shutdown happened.
*
* Views do not possess the required metadata.
* When this function is called on a view (either a MongoDB view or a [filter] logical view), a regular [count] is executed instead.
*
* ### External resources
*
* - [Official documentation](https://www.mongodb.com/docs/manual/reference/method/db.collection.estimatedDocumentCount/)
*
* @see count Perform the count for real.
*/
fun countEstimated(): Long
}