refactored collection into abstract and basic in preparation for adding relational

examples/app.ts

@@ -1,5 +1,5 @@
 import Debug from 'debug';
-import {Collection} from "../src/collection";
+import {BasicCollection} from '../src/collection-basic';
 import {Entity} from "../src/entity";
 import {RhizomeNode} from "../src/node";
 const debug = Debug('example-app');
@@ -23,7 +23,7 @@ type User = {
   // Enable API to read lossless view
   rhizomeNode.httpServer.httpApi.serveLossless();
 
-  const users = new Collection("user");
+  const users = new BasicCollection("user");
   users.rhizomeConnect(rhizomeNode);
 
   users.onUpdate((u: Entity) => {

src/collection-abstract.ts

@@ -1,38 +1,31 @@
-// A basic collection of entities
-// This may be extended to house a collection of objects that all follow a common schema.
-// It should enable operations like removing a property removes the value from the entities in the collection
-// It could then be further extended with e.g. table semantics like filter, sort, join
-
 import Debug from 'debug';
 import {randomUUID} from "node:crypto";
 import EventEmitter from "node:events";
 import {Delta} from "./delta";
 import {Entity, EntityProperties} from "./entity";
-import {LastWriteWins, ResolvedViewOne} from './last-write-wins';
+import {ResolvedViewOne} from './last-write-wins';
 import {RhizomeNode} from "./node";
 import {DomainEntityID} from "./types";
-const debug = Debug('rz:collection');
+const debug = Debug('rz:abstract-collection');
 
-export class Collection {
+export abstract class Collection<T> {
   rhizomeNode?: RhizomeNode;
   name: string;
   eventStream = new EventEmitter();
-  lossy?: LastWriteWins;
+  lossy?: T;
 
   constructor(name: string) {
     this.name = name;
   }
 
-  // Instead of trying to update our final view of the entity with every incoming delta,
-  // let's try this: 
-  // - keep a lossless view (of everything)
-  // - build a lossy view when needed
-  // This approach is simplistic, but can then be optimized and enhanced.
+  abstract initializeView(): void;
+
+  abstract resolve(id: string): ResolvedViewOne | undefined;
 
   rhizomeConnect(rhizomeNode: RhizomeNode) {
     this.rhizomeNode = rhizomeNode;
 
-    this.lossy = new LastWriteWins(this.rhizomeNode.lossless);
+    this.initializeView();
 
     // Listen for completed transactions, and emit updates to event stream
     this.rhizomeNode.lossless.eventStream.on("updated", (id) => {
@@ -43,13 +36,12 @@ export class Collection {
       this.eventStream.emit("update", res);
     });
 
-    rhizomeNode.httpServer.httpApi.serveCollection(this);
+    // TODO: Fix this
+    rhizomeNode.httpServer.httpApi.serveCollection<T>(this);
 
     debug(`[${this.rhizomeNode.config.peerId}]`, `Connected ${this.name} to rhizome`);
   }
 
-  // Applies the javascript rules for updating object values,
-  // e.g. set to `undefined` to delete a property.
   // This function is here instead of Entity so that it can:
   // - read the current state in order to build its delta
   // - include the collection name in the delta it produces
@@ -206,14 +198,4 @@ export class Collection {
     return res;
   }
 
-  resolve(
-    id: string
-  ): ResolvedViewOne | undefined {
-    if (!this.rhizomeNode) throw new Error('collection not connected to rhizome');
-    if (!this.lossy) throw new Error('lossy view not initialized');
-
-    const res = this.lossy.resolve([id]) || {};
-
-    return res[id];
-  }
 }

src/collection-basic.ts

@@ -0,0 +1,27 @@
+// A basic collection of entities
+// This may be extended to house a collection of objects that all follow a common schema.
+// It should enable operations like removing a property removes the value from the entities in the collection
+// It could then be further extended with e.g. table semantics like filter, sort, join
+
+import {Collection} from './collection-abstract';
+import {LastWriteWins, ResolvedViewOne} from './last-write-wins';
+
+export class BasicCollection extends Collection<LastWriteWins> {
+  lossy?: LastWriteWins;
+
+  initializeView() {
+    if (!this.rhizomeNode) throw new Error('not connected to rhizome');
+    this.lossy = new LastWriteWins(this.rhizomeNode.lossless);
+  }
+
+  resolve(
+    id: string
+  ): ResolvedViewOne | undefined {
+    if (!this.rhizomeNode) throw new Error('collection not connected to rhizome');
+    if (!this.lossy) throw new Error('lossy view not initialized');
+
+    const res = this.lossy.resolve([id]) || {};
+
+    return res[id];
+  }
+}

src/collection-relational.ts

@@ -0,0 +1,26 @@
+import {Collection} from "./collection-abstract";
+import {LastWriteWins, ResolvedViewOne} from "./last-write-wins";
+
+class RelationalView extends LastWriteWins {
+}
+
+export class RelationalCollection extends Collection<RelationalView> {
+  lossy?: RelationalView;
+
+  initializeView() {
+    if (!this.rhizomeNode) throw new Error('not connected to rhizome');
+    this.lossy = new RelationalView(this.rhizomeNode.lossless);
+  }
+
+  resolve(
+    id: string
+  ): ResolvedViewOne | undefined {
+    if (!this.rhizomeNode) throw new Error('collection not connected to rhizome');
+    if (!this.lossy) throw new Error('lossy view not initialized');
+
+    const res = this.lossy.resolve([id]) || {};
+
+    return res[id];
+  }
+
+}

src/entity.ts

@@ -7,7 +7,6 @@
 // - As typescript interfaces?
 // - As typescript classes?
 
-import {Collection} from "./collection";
 import {PropertyTypes} from "./types";
 
 export type EntityProperties = {
@@ -20,11 +19,5 @@ export class Entity {
 
   constructor(
     readonly id: string,
-    readonly collection?: Collection
   ) {}
-
-  async save() {
-    if (!this.collection) throw new Error('to save this entity you must specify the collection');
-    return this.collection.put(this.id, this.properties);
-  }
 }

src/http/api.ts

@@ -1,5 +1,5 @@
 import express, {Router} from "express";
-import {Collection} from "../collection";
+import {Collection} from "../collection-abstract";
 import {Delta} from "../delta";
 import {RhizomeNode} from "../node";
 
@@ -57,7 +57,8 @@ export class HttpApi {
     });
   }
 
-  serveCollection(collection: Collection) {
+  // serveCollection<T extends Collection>(collection: T) {
+  serveCollection<View>(collection: Collection<View>) {
     const {name} = collection;
 
     // Get the ID of all domain entities

src/relational.ts

@@ -1,9 +0,0 @@
-import {Collection} from "./collection";
-
-
-
-
-export class RelationalCollection extends Collection {
-  // lossy?: 
-
-}

util/app.ts

@@ -1,4 +1,4 @@
-import {Collection} from "../src/collection";
+import {BasicCollection} from "../src/collection-basic";
 import {RhizomeNode, RhizomeNodeConfig} from "../src/node";
 
 const start = 5000;
@@ -17,7 +17,7 @@ export class App extends RhizomeNode {
       ...config,
     });
 
-    const users = new Collection("user");
+    const users = new BasicCollection("user");
     users.rhizomeConnect(this);
 
     const {httpAddr, httpPort} = this.config;