## Candidate Steps

JBehave uses method annotations in Java classes to associate an executable Java method to a StepCandidate. Each step candidate corresponds to one Java method and to one StepType. A step candidate holds the regex pattern contained in the annotation value, which is used to do the matching with the textual steps in the scenarios.

Let's look at a concrete example:

For each method annotated with one of the step annotations, a step candidate is created. Note that each method can supports aliases and a different step candidate is created for each alias.

So, given one or more steps class instances, each containing one or more annotated methods, JBehave collects a list of step candidates, which are then used to match the textual steps found in the scenarios being run. For each given StepType, the regex pattern must be unique.

Hence, the following two methods are allowed to have the same regex pattern, because they correspond to different step types:

By contrast, the following would result in a runtime failure when running the scenario:

Note that in the example above TraderSteps is a POJO, i.e. it does not need to extend any JBehave class. JBehave provides the InjectableStepsFactory as a factory to create from these POJO steps instances the CandidateSteps it needs to extract the step candidates. The InstanceStepsFactory takes each steps instance provided by the user and wraps it in a Steps instance, which is the default implementation of CandidateSteps:

It is strongly recommended to define your steps instances as POJOs and to not extend the Steps class directly. This allow you not to have any tie-ins with the Steps class implementation (which may be subject to change) and also to use dependency injection to compose your steps instances using your preferred container.