Struct dittolive_ditto::store::collections::pending_collections_operation::PendingCollectionsOperation
source · [−]pub struct PendingCollectionsOperation<'order_by> { /* private fields */ }
Expand description
These objects are returned when calling collections
crate::store::Store::collections on
Store
.
They allow chaining of further collections-related functions. You can either call exec
on the
object to get an array of Collection
s as an immediate return value, or you can establish
either a live query or a subscription, which both work over time.
A live query, established by calling observe_local
, will notify you every time there’s a
change in the collections that the device knows about.
A subscription, established by calling subscribe
, will act as a signal to other peers that
the device connects to that you would like to receive updates from them about the collections
that they know about.
Typically, an app would set up a subscribe
in some part of the application which is long-lived
to ensure the device receives updates from the mesh. These updates will be automatically
received and written into the local store. Elsewhere, where you need to use this data, an
observe_local
can be used to notify you of the data, and all subsequent changes to the data.
Implementations
sourceimpl<'order_by> PendingCollectionsOperation<'order_by>
impl<'order_by> PendingCollectionsOperation<'order_by>
sourcepub fn limit(&mut self, limit: i32) -> &mut Self
pub fn limit(&mut self, limit: i32) -> &mut Self
Limit the number of documents that get returned when querying a collection for matching documents.
sourcepub fn offset(&mut self, offset: u32) -> &mut Self
pub fn offset(&mut self, offset: u32) -> &mut Self
Offset the resulting set of matching documents. This is useful if you aren’t interested in the first N matching documents for one reason or another. For example, you might already have queried the collection and obtained the first 20 matching documents and so you might want to run the same query as you did previously but ignore the first 20 matching documents, and that is where you would use offset.
sourcepub fn sort(&mut self, sort_param: Vec<COrderByParam<'order_by>>) -> &mut Self
pub fn sort(&mut self, sort_param: Vec<COrderByParam<'order_by>>) -> &mut Self
Sort the documents that match the query provided in the preceding find-like function call.
sourcepub fn exec(&self) -> Result<Vec<Collection>, DittoError>
pub fn exec(&self) -> Result<Vec<Collection>, DittoError>
Execute the query generated by the preceding function chaining and return the list of matching documents. This occurs immediately.
sourcepub fn subscribe(&self) -> Subscription
pub fn subscribe(&self) -> Subscription
Enables you to subscribe to changes that occur on a collection. Having a subscription acts
as a signal to others that you are interested in receiving updates when local or remote
changes are made to documents that match the query generated by the chain of operations that
precedes the call to subscribe. The returned Subscription
object must be kept in scope for as long as you want to keep receiving updates.
sourcepub fn observe_local<Handler>(
&self,
handler: Handler
) -> Result<LiveQuery, DittoError>where
Handler: CollectionsEventHandler,
pub fn observe_local<Handler>(
&self,
handler: Handler
) -> Result<LiveQuery, DittoError>where
Handler: CollectionsEventHandler,
Enables you to listen for changes that occur on a collection. This won’t subscribe to
receive changes made remotely by others and so it will only fire updates when a local change
is made. If you want to receive remotely performed updates as well then also call subscribe
with the relevant query. The returned LiveQuery
object
must be kept in scope for as long as you want the provided Handler
to be called when an
update occurs.
Auto Trait Implementations
impl<'order_by> RefUnwindSafe for PendingCollectionsOperation<'order_by>
impl<'order_by> Send for PendingCollectionsOperation<'order_by>
impl<'order_by> Sync for PendingCollectionsOperation<'order_by>
impl<'order_by> Unpin for PendingCollectionsOperation<'order_by>
impl<'order_by> UnwindSafe for PendingCollectionsOperation<'order_by>
Blanket Implementations
sourceimpl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
impl<T> CompatExt for T
impl<T> CompatExt for T
fn compat_ref(&self) -> Compat<&T>
fn compat_ref(&self) -> Compat<&T>
Compat
] adapter by shared reference. Read morefn compat_mut(&mut self) -> Compat<&mut T>
fn compat_mut(&mut self) -> Compat<&mut T>
Compat
] adapter by mutable reference. Read more