From 0d855c3c10abf53aa38682324dd30e99b15b9d41 Mon Sep 17 00:00:00 2001
From: "daniel.eades" <daniel.eades@seebyte.com>
Date: Thu, 2 Jan 2025 15:00:33 +0000
Subject: [PATCH] update the 'View' trait

---
 src/persist/doc.rs             | 9 +++++----
 src/persist/generic_query.rs   | 8 ++++----
 src/persist/view_repository.rs | 2 +-
 src/query.rs                   | 6 ++++--
 4 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/src/persist/doc.rs b/src/persist/doc.rs
index a9764bc..bd610c3 100644
--- a/src/persist/doc.rs
+++ b/src/persist/doc.rs
@@ -1,10 +1,10 @@
-use crate::doc::MyAggregate;
+use crate::doc::{MyAggregate, MyEvents};
 use crate::persist::event_stream::ReplayStream;
 use crate::persist::{
     PersistedEventRepository, PersistenceError, SerializedEvent, SerializedSnapshot, ViewContext,
     ViewRepository,
 };
-use crate::{Aggregate, EventEnvelope, View};
+use crate::{Aggregate, View};
 use async_trait::async_trait;
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
@@ -12,8 +12,9 @@ use serde_json::Value;
 #[derive(Debug, Default, Serialize, Deserialize)]
 pub struct MyView;
 
-impl View<MyAggregate> for MyView {
-    fn update(&mut self, _event: &EventEnvelope<MyAggregate>) {
+impl View for MyView {
+    type Event = MyEvents;
+    fn apply(&mut self, _event: &Self::Event) {
         todo!()
     }
 }
diff --git a/src/persist/generic_query.rs b/src/persist/generic_query.rs
index bafefb9..4840c92 100644
--- a/src/persist/generic_query.rs
+++ b/src/persist/generic_query.rs
@@ -11,7 +11,7 @@ use crate::{Aggregate, EventEnvelope, Query, View};
 pub struct GenericQuery<R, V, A>
 where
     R: ViewRepository<V, A>,
-    V: View<A>,
+    V: View<Event = A::Event>,
     A: Aggregate,
 {
     view_repository: Arc<R>,
@@ -22,7 +22,7 @@ where
 impl<R, V, A> GenericQuery<R, V, A>
 where
     R: ViewRepository<V, A>,
-    V: View<A>,
+    V: View<Event = A::Event>,
     A: Aggregate,
 {
     /// Creates a new `GenericQuery` using the provided `ViewRepository`.
@@ -102,7 +102,7 @@ where
     ) -> Result<(), PersistenceError> {
         let (mut view, view_context) = self.load_mut(view_id.to_string()).await?;
         for event in events {
-            view.update(event);
+            view.apply(&event.payload);
         }
         self.view_repository.update_view(view, view_context).await?;
         Ok(())
@@ -119,7 +119,7 @@ where
 impl<R, V, A> Query<A> for GenericQuery<R, V, A>
 where
     R: ViewRepository<V, A>,
-    V: View<A>,
+    V: View<Event = A::Event>,
     A: Aggregate,
 {
     async fn dispatch(&self, view_id: &str, events: &[EventEnvelope<A>]) {
diff --git a/src/persist/view_repository.rs b/src/persist/view_repository.rs
index 56e151c..1ea35de 100644
--- a/src/persist/view_repository.rs
+++ b/src/persist/view_repository.rs
@@ -6,7 +6,7 @@ use async_trait::async_trait;
 #[async_trait]
 pub trait ViewRepository<V, A>: Send + Sync
 where
-    V: View<A>,
+    V: View<Event = A::Event>,
     A: Aggregate,
 {
     /// Returns the current view instance.
diff --git a/src/query.rs b/src/query.rs
index df9b77b..d689b24 100644
--- a/src/query.rs
+++ b/src/query.rs
@@ -23,8 +23,10 @@ pub trait Query<A: Aggregate>: Send + Sync {
 /// A `View` represents a materialized view, generally serialized for persistence, that is updated by a query.
 /// This a read element in a CQRS system.
 ///
-pub trait View<A: Aggregate>: Debug + Default + Serialize + DeserializeOwned + Send + Sync {
+pub trait View: Debug + Default + Serialize + DeserializeOwned + Send + Sync {
+    /// The event type that this view is constructed from
+    type Event;
     /// Each implemented view is responsible for updating its state based on events passed via
     /// this method.
-    fn update(&mut self, event: &EventEnvelope<A>);
+    fn apply(&mut self, event: &Self::Event);
 }