Struct dittolive_ditto::store::collection::pending_cursor_operation::PendingCursorOperation
source · [−]pub struct PendingCursorOperation<'order_by> { /* private fields */ }
Expand description
These objects are returned when using find
-like functionality on Collection
s.
They allow chaining of further query-related functions to do things like add a limit to the
number of documents you want returned or specify how you want the documents to be sorted and
ordered. You can either call exec
on the object to get an array of Document
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 an
update to a document that matches the query you provided in the preceding find
-like call.
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 documents
that match the query you provided in the preceding find
-like call.
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
observeLocal
can be used to notify you of the data, and all subsequent changes to the data.
Update and remove functionality is also exposed through this object.
Implementations
sourceimpl<'order_by> PendingCursorOperation<'order_by>
impl<'order_by> PendingCursorOperation<'order_by>
pub fn new(
ditto: Weak<BoxedDitto>,
collection_name: Box,
query: &str,
query_args: Option<Vec<u8>>
) -> Self
sourcepub fn exec(&self) -> Result<Vec<BoxedDocument>, DittoError>
pub fn exec(&self) -> Result<Vec<BoxedDocument>, 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.
Panics
Panics if Ditto has been closed.
sourcepub fn update<Updater>(
&self,
updater: Updater
) -> Result<BTreeMap<DocumentId, Vec<UpdateResult>>, DittoError>where
Updater: Fn(&mut [BoxedDocument]),
pub fn update<Updater>(
&self,
updater: Updater
) -> Result<BTreeMap<DocumentId, Vec<UpdateResult>>, DittoError>where
Updater: Fn(&mut [BoxedDocument]),
Update the document with the matching document Id.
updater
: amFn
which will be called on all matching documents.
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 remove(&self) -> Result<Vec<DocumentId>, DittoError>
pub fn remove(&self) -> Result<Vec<DocumentId>, DittoError>
Remove all documents that match the query generated by the preceding function chaining. Returns the IDs of all documents removed
sourcepub fn evict(&self) -> Result<Vec<DocumentId>, DittoError>
pub fn evict(&self) -> Result<Vec<DocumentId>, DittoError>
Evict all documents that match the query generated by the preceding function chaining.
sourcepub fn observe_local<Handler>(
&self,
handler: Handler
) -> Result<LiveQuery, DittoError>where
Handler: EventHandler,
pub fn observe_local<Handler>(
&self,
handler: Handler
) -> Result<LiveQuery, DittoError>where
Handler: EventHandler,
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 you need to 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.
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.
Auto Trait Implementations
impl<'order_by> RefUnwindSafe for PendingCursorOperation<'order_by>
impl<'order_by> Send for PendingCursorOperation<'order_by>
impl<'order_by> Sync for PendingCursorOperation<'order_by>
impl<'order_by> Unpin for PendingCursorOperation<'order_by>
impl<'order_by> UnwindSafe for PendingCursorOperation<'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