Design Patterns MCP Server

{ "id": "active-object", "name": "Active Object", "category": "Concurrency", "description": "Decouples method execution from method invocation using asynchronous messaging", "when_to_use": "Asynchronous execution\nRequest queuing\nConcurrent services", "benefits": "Asynchronous execution\nDecoupling\nRequest queuing\nConcurrency", "drawbacks": "Complex implementation\nMemory overhead\nDebugging difficulty", "use_cases": "Concurrent services\nAsynchronous APIs\nMessage processing", "complexity": "High", "tags": [ "concurrency", "asynchronous", "messaging" ], "examples": { "typescript": { "language": "typescript", "code": "// Active Object: async method invocation with own thread\ntype MethodRequest = {\n execute: () => Promise<any>;\n future: Promise<any>;\n resolve: (value: any) => void;\n};\n\nclass ActiveObject {\n private queue: MethodRequest[] = [];\n private running = false;\n \n protected async invoke<T>(method: () => Promise<T>): Promise<T> {\n const request = this.createRequest(method);\n this.queue.push(request);\n \n if (!this.running) {\n this.scheduler();\n }\n \n return request.future;\n }\n \n private createRequest<T>(method: () => Promise<T>): MethodRequest {\n let resolve!: (value: T) => void;\n const future = new Promise<T>(r => resolve = r);\n \n return {\n execute: method,\n future,\n resolve\n };\n }\n \n private async scheduler() {\n this.running = true;\n \n while (this.queue.length > 0) {\n const request = this.queue.shift()!;\n const result = await request.execute();\n request.resolve(result);\n }\n \n this.running = false;\n }\n}\n\nclass AsyncLogger extends ActiveObject {\n async log(message: string): Promise<void> {\n return this.invoke(async () => {\n console.log('[' + new Date().toISOString() + ']', message);\n await new Promise(resolve => setTimeout(resolve, 100));\n });\n }\n}\n\nconst logger = new AsyncLogger();\nlogger.log('Message 1'); // Non-blocking\nlogger.log('Message 2'); // Queued\nlogger.log('Message 3'); // Queued" } } }