Struct MockStream

pub struct MockStream<I> { /* private fields */ }

A simple struct that helps create RowStreams from vectors.

Implementations

impl<I> MockStream<I>

where I: Iterator<Item = RowResult>,

pub fn new(iter: I, headers: Headers) -> MockStream<I>

Creates a new object implementing the RowStream trait from an iterator and some headers.

pub fn from_rows(iter: I) -> Result<MockStream<I>, BuildError>

Creates a new object implementing the RowStream trait from an iterator of RowResult objects, the first of which must be the header row.

Trait Implementations

impl<I: Debug> Debug for MockStream<I>

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

Formats the value using the given formatter.

impl<I> IntoIterator for MockStream<I>

where I: Iterator<Item = RowResult>,

type Item = Result<StringRecord, Error>

The type of the elements being iterated over.

type IntoIter = IntoIter<I>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<I> RowStream for MockStream<I>

where MockStream<I>: IntoIterator<Item = RowResult>,

fn headers(&self) -> &Headers

Must return headers as they are in this point of the chain. For example if implementor adds a column, its headers() function must return the new headers including the one just added.

fn add(self, column: ColSpec) -> Result<Add<Self>>

where Self: Sized,

Add a column to each row of the stream.

fn del(self, columns: Vec<&str>) -> Del<'_, Self>

where Self: Sized,

Deletes the specified columns from each row of the stream. If you have too many columns to delete perhaps instead use RowStream::select.

fn select(self, columns: Vec<&str>) -> Select<'_, Self>

where Self: Sized,

Outputs only the selected columns, ignoring the rest.

fn add_with<F>( self, colname: &str, f: F, ) -> Result<AddWith<Self, F>, BuildError>

where Self: Sized, F: FnMut(&Headers, &Row) -> Result<String>,

Adds a column to each row of the stream using a closure to compute its value.

fn reduce(self, columns: Vec<Box<dyn Aggregate>>) -> Result<Reduce<Self>>

where Self: Sized,

Reduce all the incoming stream into one row, computing some aggregates in the way. All the stream collapses into one row.

fn adjacent_group<F, R, G>(self, grouping: G, f: F) -> AdjacentGroup<Self, F, G>

where F: Fn(MockStream<IntoIter<RowResult>>) -> R, R: RowStream, G: GroupCriteria, Self: Sized,

Groups rows by the given criteria, but assuming a “group” is a set of adjacent rows.

fn group<F, R, G>(self, grouping: G, f: F) -> Group<Self, F, G>

where F: Fn(MockStream<IntoIter<RowResult>>) -> R, R: RowStream, G: GroupCriteria, Self: Sized,

Groups rows by the given criteria. You’ll be given a RowStream instance as the first argument of a closure that you can use to further process the grouped rows.

fn flush<T>(self, target: T) -> Result<Flush<Self, T>>

where Self: Sized,

When consumed, writes to destination specified by the column given in the first argument. Other than that this behaves like an id(x) function so you can specify more links in the chain and even more flushers.

fn review<F>(self, f: F) -> Inspect<Self, F>

where Self: Sized, F: FnMut(&Headers, &RowResult),

Mostly for debugging, calls a closure on each element. Behaves like the identity function on the stream returning each row untouched.

fn rename(self, old_name: &str, new_name: &str) -> Rename<Self>

where Self: Sized,

Renames some columns

fn map_row<F, H, R>(self, f: F, header_map: H) -> MapRow<Self, F>

where Self: Sized, F: Fn(&Headers, &Row) -> Result<R>, H: Fn(&Headers) -> Headers, R: Iterator<Item = RowResult>,

Apply a function to every row and use the return values to build the row stream.

fn map_col<F>(self, col: &str, f: F) -> MapCol<Self, F>

where Self: Sized, F: Fn(&str) -> Result<String>,

Apply a function to a single column of the stream, this function dones’t fail if the column dones’t exist.

fn filter_col<F>(self, col: &str, f: F) -> Result<FilterCol<Self, F>>

where Self: Sized, F: Fn(&str) -> bool,

filter entire rows out depending on one column’s value and a condition, leaving errored rows untouched.

fn filter_row<F>(self, f: F) -> FilterRow<Self, F>

where Self: Sized, F: Fn(&Headers, &Row) -> bool,

filter entire rows out depending on one column’s value and a condition, leaving errored rows untouched.