Struct qldb::DocumentCollection

pub struct DocumentCollection { /* fields omitted */ }

Represents a collection of documents. It implements so you can call in order to use it in for loops or with .

It implements too.

It adds some utilities methods in order to do common operations.

You can use the into_iter in order to execute aggregate values or to make other complex operation.

use qldb::{DocumentCollection, QldbExtractResult};

// Adds all the "points" attributes from each document.
// It stops early in case of error extracting the attribute.
fn count_points(matches: DocumentCollection) -> QldbExtractResult<u64> {

    // You can use other types as BigUInt, BigDecimal, etc
    // in order to avoid overflow

    let result: u64 = matches
        .into_iter()
        .map(|doc| doc.get_value::<u64>("points"))
        .collect::<Result<Vec<u64>, _>>()?
        .into_iter()
        .fold(0, |acc, val| acc + val);

    Ok(result)
}

Implementations

impl DocumentCollection

pub fn new(documents: Vec<Document>) -> DocumentCollection

pub fn into_inner(self) -> Vec<Document>

pub fn into_vec(self) -> Vec<Document>

pub fn len(&self) -> usize

pub fn is_empty(&self) -> bool

Trait Implementations

impl AsRef<Vec<Document, Global>> for DocumentCollection

fn as_ref(&self) -> &Vec<Document>

Performs the conversion.

impl Clone for DocumentCollection

fn clone(&self) -> DocumentCollection

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for DocumentCollection

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for DocumentCollection

fn default() -> Self

Returns the “default value” for a type.

impl Extend<Document> for DocumentCollection

fn extend<T: IntoIterator<Item = Document>>(&mut self, iter: T)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬 This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬 This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl Index<usize> for DocumentCollection

type Output = Document

The returned type after indexing.

fn index(&self, index: usize) -> &Self::Output

Performs the indexing (container[index]) operation.

impl IntoIterator for DocumentCollection

type Item = Document

The type of the elements being iterated over.

type IntoIter = IntoIter<Self::Item>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl PartialEq<DocumentCollection> for DocumentCollection

fn eq(&self, other: &DocumentCollection) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &DocumentCollection) -> bool

This method tests for !=.

impl TryFrom<Vec<IonValue, Global>> for DocumentCollection

type Error = QldbExtractError

The type returned in the event of a conversion error.

fn try_from(ion_values_vector: Vec<IonValue>) -> Result<Self, Self::Error>

Performs the conversion.

impl StructuralPartialEq for DocumentCollection