Package com.datastax.astra.client.collections.commands.cursor

Class CollectionDistinctIterable<T,F>

java.lang.Object

com.datastax.astra.client.core.paging.PageableIterable<T>

com.datastax.astra.client.collections.commands.cursor.CollectionDistinctIterable<T,F>

Type Parameters:

T - type of the document used in the associated collection.

F - type of the field we are looping on.

All Implemented Interfaces:

Closeable, AutoCloseable, Iterable<F>

public class CollectionDistinctIterable<T,F>
extends PageableIterable<T>
implements Iterable<F>

Iterator to get all distinct value for a particular field.

Field Summary

Fields

Modifier and Type	Field	Description
protected DistinctIterator<T,F>	currentPageIterator	Iterator on fields.

Fields inherited from class com.datastax.astra.client.core.paging.PageableIterable

active, collection, currentPage, currentPageAvailable, exhausted, filter, options, totalItemProcessed

Constructor Summary

Constructors

Constructor	Description
CollectionDistinctIterable(Collection<T> collection, String fieldName, Filter filter, Class<F> fieldClass)	Constructs an iterable that provides distinct elements from a specified collection, optionally filtered by a given criterion.

Method Summary

Modifier and Type	Method	Description
List<F>	all()	Will exhaust the list and put all value in memory.
@NonNull DistinctIterator<T,F>	iterator()

Methods inherited from class com.datastax.astra.client.core.paging.PageableIterable

close, fetchNextPage, getSortVector

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Details

currentPageIterator

protected DistinctIterator<T,F> currentPageIterator

Iterator on fields.

Constructor Details

CollectionDistinctIterable

public CollectionDistinctIterable(Collection<T> collection,
 String fieldName,
 Filter filter,
 Class<F> fieldClass)

Constructs an iterable that provides distinct elements from a specified collection, optionally filtered by a given criterion. This iterable allows for iterating over unique values of a specific field within the collection's documents, which can be particularly useful for data analysis, reporting, or implementing specific business logic that requires uniqueness in the dataset.

The distinct elements are determined based on the fieldName parameter, ensuring that each value provided during iteration is unique with respect to this field across all documents in the collection. The filter parameter allows for narrowing down the documents considered by this iterable, offering the capability to perform more targeted queries.

Parameters:

collection - The source collection client, used to fetch documents and, if necessary, subsequent pages of results. This collection should be capable of executing queries and returning filtered results.

fieldName - The name of the field for which unique values are to be iterated over. This field's values are used to determine the distinctness of elements provided by this iterable.

filter - The original filter used to limit the documents considered for finding distinct values. This filter allows for the specification of criteria that documents must meet to be included in the iteration.

fieldClass - The class of the field values being iterated over. This parameter is used to ensure type safety and proper casting of the field values extracted from the documents in the collection.

Method Details

iterator

@NonNull
public @NonNull DistinctIterator<T,F> iterator()

Specified by:

iterator in interface Iterable<T>

all

public List<F> all()

Will exhaust the list and put all value in memory.

Returns:

all values of the iterable