Implement the copyProjectionToMongoDB decorator

Author: jakhog

Source/projections/Builders/Copies/CopyProjectionToMongoDBDecoratedType.ts

@@ -0,0 +1,21 @@
+// Copyright (c) Dolittle. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+import { Constructor } from '@dolittle/types';
+
+import { CollectionName } from '../../Copies/MongoDB/CollectionName';
+
+/**
+ * Represents a projection decorated with the a 'copyToMongoDB' decorator.
+ */
+export class CopyProjectionToMongoDBDecoratedType {
+    /**
+     * Initialises a new instance of the {@link CopyProjectionToMongoDBDecoratedType} class.
+     * @param {CollectionName} collection - The collection name to use.
+     * @param {Constructor<any>} type - The decorated type.
+     */
+    constructor(
+        readonly collection: CollectionName,
+        readonly type: Constructor<any>,
+    ) {}
+}

Source/projections/Builders/Copies/_exports.ts

@@ -1,6 +1,8 @@
 // Copyright (c) Dolittle. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
+export { CopyProjectionToMongoDBDecoratedType } from './CopyProjectionToMongoDBDecoratedType';
+export { copyProjectionToMongoDB, isDecoratedCopyProjectionToMongoDB, getDecoratedCopyProjectionToMongoDB } from './copyProjectionToMongoDBDecorator';
 export { CopyToMongoDBBuilder } from './CopyToMongoDBBuilder';
 export { CopyToMongoDBCallback } from './CopyToMongoDBCallback';
 export { ICopyToMongoDBBuilder } from './ICopyToMongoDBBuilder';

Source/projections/Builders/Copies/copyProjectionToMongoDBDecorator.ts

@@ -0,0 +1,41 @@
+// Copyright (c) Dolittle. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+import { Decorators } from '@dolittle/sdk.common';
+import { Constructor } from '@dolittle/types';
+import { CollectionName, CollectionNameLike } from '../../Copies/MongoDB/CollectionName';
+
+import { CopyProjectionToMongoDBDecoratedType } from './CopyProjectionToMongoDBDecoratedType';
+
+const [decorator, getMetadata] = Decorators.createMetadataDecorator<CopyProjectionToMongoDBDecoratedType>('copy-projection-to-mongodb', 'copyProjectionToMongoDB', Decorators.DecoratorTarget.Class);
+
+/**
+ * Decorator to mark a Projection class to copy the read models to a MongoDB collection.
+ * @param {CollectionNameLike} [collection] - An optional collection name to use, defaults to the name of the class.
+ * @returns {Decorators.Decorator} The decorator.
+ */
+export function copyProjectionToMongoDB(collection?: CollectionNameLike): Decorators.Decorator {
+    return decorator((target, type) => {
+        return new CopyProjectionToMongoDBDecoratedType(
+            CollectionName.from(collection ?? type.name),
+            type);
+    });
+}
+
+/**
+ * Checks whether the specified class is decorated with a copy to MongoDB decorator.
+ * @param {Constructor<any>} type - The class to get the decorated copy to MongoDB for.
+ * @returns {boolean} True if the decorator is applied, false if not.
+ */
+export function isDecoratedCopyProjectionToMongoDB(type: Constructor<any>): boolean {
+    return getMetadata(type, false, false) !== undefined;
+}
+
+/**
+ * Gets the {@link CopyProjectionToMongoDBDecoratedType} of the specified class.
+ * @param {Constructor<any>} type - The class to get the decorated copy to MongoDB for.
+ * @returns {CopyProjectionToMongoDBDecoratedType} The decorated projection type.
+ */
+export function getDecoratedCopyProjectionToMongoDB(type: Constructor<any>): CopyProjectionToMongoDBDecoratedType {
+    return getMetadata(type, true, 'Projection classes to be copied to MongoDB must be decorated');
+}

Source/projections/Builders/ProjectionClassBuilder.ts

@@ -17,6 +17,8 @@ import { OnDecoratedProjectionMethod } from './OnDecoratedProjectionMethod';
 import { getOnDecoratedMethods } from './onDecorator';
 import { ProjectionDecoratedType } from './ProjectionDecoratedType';
 import { ProjectionCopies } from '../Copies/ProjectionCopies';
+import { MongoDBCopies } from '../Copies/MongoDB/MongoDBCopies';
+import { getDecoratedCopyProjectionToMongoDB, isDecoratedCopyProjectionToMongoDB } from './Copies/copyProjectionToMongoDBDecorator';
 
 /**
  * Represents a builder for building a projection from a class.
@@ -55,8 +57,9 @@ export class ProjectionClassBuilder<T> implements IEquatable {
             results.addFailure(`Could not create projection ${this.type.type.name} because it contains invalid projection methods`, 'Maybe you have multiple @on methods handling the same event type?');
             return;
         }
-        const copies = ProjectionCopies.default;
-        //TODO: Create copies.
+
+        const copies = this.buildCopies(results);
+
         return new Projection<T>(this.type.projectionId, this.type.type, this.type.scopeId, events, copies);
     }
 
@@ -116,4 +119,22 @@ export class ProjectionClassBuilder<T> implements IEquatable {
             return instance;
         };
     }
+
+    private buildCopies(results: IClientBuildResults): ProjectionCopies {
+        return new ProjectionCopies(
+            this.buildMongoDBCopies(results),
+        );
+    }
+
+    private buildMongoDBCopies(results: IClientBuildResults): MongoDBCopies {
+        if (!isDecoratedCopyProjectionToMongoDB(this.type.type)) {
+            return MongoDBCopies.default;
+        }
+
+        const decoratedType = getDecoratedCopyProjectionToMongoDB(this.type.type);
+
+        // TODO: Conversions
+
+        return new MongoDBCopies(true, decoratedType.collection, new Map());
+    }
 }

Source/projections/Builders/_exports.ts

@@ -1,6 +1,8 @@
 // Copyright (c) Dolittle. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
+export * as Copies from './Copies/_exports';
+
 export { CouldNotCreateInstanceOfProjection } from './CouldNotCreateInstanceOfProjection';
 export { IProjectionBuilder } from './IProjectionBuilder';
 export { IProjectionBuilderForReadModel } from './IProjectionBuilderForReadModel';

Source/projections/index.ts

@@ -32,6 +32,10 @@ export {
 } from './Builders/_exports';
 
 export {
+    copyProjectionToMongoDB,
+    isDecoratedCopyProjectionToMongoDB,
+    getDecoratedCopyProjectionToMongoDB,
+    CopyProjectionToMongoDBDecoratedType,
     CopyToMongoDBBuilder,
     CopyToMongoDBCallback,
     ICopyToMongoDBBuilder,