define static method

StepBuilder define(String name)

Define a Step using a StepBuilder.

This method returns a builder which has two methods dep and build. Calling builder.dep(stepA) adds a dependency on stepA and returns a new builder. Calling builder.build(runStep) creates a Step<T> if runStep is a function that returns T and takes the result value from dependent steps.

As adding new dependenices with builder.dep changes the number of arguments for the runStep method required by the builder.build method, the type of the builder will be StepBuilder, StepBuilder1 through StepBuilder9 depending on the number of dependenices. The StepBuilder types have the same interface, except the StepBuilder and StepBuilder9 which offers a builder.deps(Iterable<Step<S>> steps) method that allows for an arbitrary number of dependencies. This useful if all the dependent steps have the same type, or if a step has more than 9 dependencies.

Example

// Define a step without dependencies
final Step<Router> routerStep = Step.define('router').build(() {
  return Router(/* setup request router */);
});

// Define a step without dependencies
final Step<Database> databaseStep = Step.define('database').build(() {
  return Database(/* setup database connection and schema */);
});

// Define a step with two dependencies
final Step<Server> server = Step.define('server')
    .dep(routerStep)
    .dep(databaseStep)
    .build((router, router) async {
  // Setup Server using router and database
});

Implementation

static StepBuilder define(String name) => StepBuilder._(name);