Refactor command handlers information

Author: rsaladocid

src/Contexts/Shared/domain/CommandNotRegisteredError.ts

@@ -0,0 +1,7 @@
+import { Command } from './Command';
+
+export class CommandNotRegisteredError extends Error {
+  constructor(command: Command) {
+    super(`The command <${command.constructor.name}> hasn't a command handler associated`);
+  }
+}

src/Contexts/Shared/infrastructure/CommandBus/CommandHandlersInformation.ts

@@ -1,5 +1,6 @@
 import { Command } from '../../domain/Command';
 import { CommandHandler } from '../../domain/CommandHandler';
+import { CommandNotRegisteredError } from '../../domain/CommandNotRegisteredError';
 
 export class CommandHandlersInformation {
   private commandHandlersMap: Map<Command, CommandHandler<Command>>;
@@ -18,7 +19,13 @@ export class CommandHandlersInformation {
     return handlersMap;
   }
 
-  public getCommandHandler(command: Command): CommandHandler<Command> | undefined {
-    return this.commandHandlersMap.get(command.constructor);
+  public search(command: Command): CommandHandler<Command> {
+    const commandHandler = this.commandHandlersMap.get(command.constructor);
+
+    if (!commandHandler) {
+      throw new CommandNotRegisteredError(command);
+    }
+
+    return commandHandler;
   }
 }

src/Contexts/Shared/infrastructure/CommandBus/InMemoryCommandBus.ts

@@ -1,17 +1,12 @@
 import { Command } from '../../domain/Command';
 import { CommandBus } from './../../domain/CommandBus';
 import { CommandHandlersInformation } from './CommandHandlersInformation';
-import { NoHandlerForMessageError } from './NoHandlerForMessageError';
 
 export class InMemoryCommandBus implements CommandBus {
   constructor(private commandHandlersInformation: CommandHandlersInformation) {}
 
   dispatch(command: Command): void {
-    const handler = this.commandHandlersInformation.getCommandHandler(command);
-
-    if (!handler) {
-      throw new NoHandlerForMessageError(command);
-    }
+    const handler = this.commandHandlersInformation.search(command);
 
     handler.handle(command);
   }

src/Contexts/Shared/infrastructure/CommandBus/NoHandlerForMessageError.ts

@@ -1,8 +1,8 @@
 import { Command } from '../../../../../src/Contexts/Shared/domain/Command';
 import { CommandHandler } from '../../../../../src/Contexts/Shared/domain/CommandHandler';
+import { CommandNotRegisteredError } from '../../../../../src/Contexts/Shared/domain/CommandNotRegisteredError';
 import { CommandHandlersInformation } from '../../../../../src/Contexts/Shared/infrastructure/CommandBus/CommandHandlersInformation';
 import { InMemoryCommandBus } from '../../../../../src/Contexts/Shared/infrastructure/CommandBus/InMemoryCommandBus';
-import { NoHandlerForMessageError } from '../../../../../src/Contexts/Shared/infrastructure/CommandBus/NoHandlerForMessageError';
 
 class UnhandledCommand extends Command {
   static COMMAND_NAME = 'unhandled.command';
@@ -29,8 +29,8 @@ describe('InMemoryCommandBus', () => {
     try {
       commandBus.dispatch(unhandledCommand);
     } catch (error) {
-      expect(error).toBeInstanceOf(NoHandlerForMessageError);
-      expect(error.message).toBe('There is not handler for command of type UnhandledCommand');
+      expect(error).toBeInstanceOf(CommandNotRegisteredError);
+      expect(error.message).toBe(`The command <UnhandledCommand> hasn't a command handler associated`);
       done();
     }
   });