ICommandInterceptor

An interface for stackable command interceptors, which can extend and modify the command call chain.

Description

The ICommandInterceptor interface is used for stackable command interceptors, which can extend and modify the command call chain.

Important points

  • This technique can be used for authentication, logging, and several other functions.

Instance methods

getName

Gets the name of the wrapped command.

The interceptor can use this method to override the command name. Otherwise, it shall just delegate the call to the wrapped command.

String getName(ICommand command)

  • command: ICommand - next command in the call chain.
  • returns: String - name of the wrapped command.

execute

Executes the wrapped command with specified arguments.

The interceptor can use this method to intercept and alter the command execution. Otherwise, it shall just delete the call to the wrapped command.

Future<dynamic> execute(String? correlationId, ICommand command, Parameters args)

  • correlationId: String? - (optional) transaction id to used trace execution through the call chain.
  • command: ICommand - next command in the call chain that is to be executed.
  • args: Parameters - parameters (arguments) to pass to the command for execution.
  • returns: Future<dynamic> - execution result.

validate

Validates the arguments of the wrapped command before its execution.

The interceptor can use this method to intercept and alter validation of the command arguments. Otherwise, it shall just delegate the call to the wrapped command.

List<ValidationResult> validate(ICommand command, Parameters args)

  • command: ICommand - next command in the call chain to be validated against.
  • args: Parameters - parameters (arguments) to validate.
  • returns: List<ValidationResult> - array of ValidationResults.

See also