hsm.action_state.ActionState

class ActionState(action, spec=None, goal=None, name=None, server_wait_timeout=10.0)

Bases: Container

Simple action client state.

Use this class to represent an actionlib as a state in a state machine.

Constructor for ActionState action client wrapper.

@type action: actionlib.SimpleActionClient | string @param action: SimpleActionClient instance to use or name of ROS action to create a client for

@type spec: actionlib action msg @param spec: The type of action to which this client will connect.

@type goal: actionlib goal msg @param goal: If the goal for this action does not need to be generated at runtime, it can be passed to this state on construction.

@type server_wait_timeout: C{rospy.Duration} @param server_wait_timeout: This is the timeout used for aborting while waiting for an action server to become active.

The reported status (‘PENDING’,’ACTIVE’,’PREEMPTED’,’SUCCEEDED’,’ABORTED’,’REJECTED’,’LOST’) is dispatched as an HSM event. If the connection to the action server could not be established within the given timeout, a ‘TIMEOUT’ event is dispatched.

Methods

`add_handler`	Add a new event callback.
`add_state`	Add a state to a state the container.
`add_states`	Add multiple states to the Container.
`add_transition`	Add a transition from self to target_state
`feedback_cb`
`get_active_states`
`get_initial_states`
`is_active`
`is_substate`	Check whether the state is a substate of self.
`ros_subscribe`
`set_initial_state`	Set an initial state in a state machine.

Attributes

`ACTIVE`
`EXITING`
`INACTIVE`
`PENDING`
`WAITING_FOR_SERVER`
`history_state`	Get the history state of this `Container`.
`initial_state`	Get the initial state in a state machine.
`leaf_state`	Get the current leaf state.
`root`	Get the root state in a states hierarchy.

add_handler(events, func, prepend=False)

Add a new event callback.

Parameters:

trigger (str) – name of triggering event
func (callable) – callback function

add_state(state, initial=False)

Add a state to a state the container.

If states are added, one (and only one) of them has to be declared as initial.

Parameters:

state (State) – State to be added. It may be an another Container
initial (bool) – Declare a state as initial

add_states(*states)

Add multiple states to the Container.

Parameters:: states – A list of states to be added

add_transition(events, target_state, *args, **kwargs)

Add a transition from self to target_state

All callbacks take two arguments - state and event. See parameters description for details.

It is possible to create conditional if/elif/else-like logic for transitions. To do so, add many same transition rules with different condition callbacks. First met condition will trigger a transition, if no condition is met, no transition is performed.

Parameters:

target_state (State, None) – Target state. If None, then it’s an internal transition
events (Iterable of Hashable) – List of events that trigger the transition
condition (Callable) –
Condition callback - if returns True transition may be initiated.

condition callback takes two arguments:
- state: Leaf state before transition
- event: Event that triggered the transition
action (Callable) –
Action callback that is called during the transition after all states have been left but before the new one is entered.

action callback takes two arguments:
- state: Leaf state before transition
- event: Event that triggered the transition
before (Callable) –
Action callback that is called right before the transition.

before callback takes two arguments:
- state: Leaf state before transition
- event: Event that triggered the transition
after (Callable) –
Action callback that is called just after the transition

after callback takes two arguments:
- state: Leaf state after transition
- event: Event that triggered the transition

property history_state

Get the history state of this Container.

Returns:: Leaf state in a hierarchical state machine
Return type:: State

property initial_state

Get the initial state in a state machine.

Returns:: Initial state in a state machine
Return type:: State

is_substate(state)

Check whether the state is a substate of self.

Also self is considered a substate of self.

Parameters:: state (State) – State to verify
Returns:: True if state is a substate of self, False otherwise
Return type:: bool

property leaf_state

Get the current leaf state.

The state property gives the current, local state in a state machine. The leaf_state goes to the bottom in a hierarchy of states. In most cases, this is the property that should be used to get the current state in a state machine, even in a flat FSM, to keep the consistency in the code and to avoid confusion.

Returns:: Leaf state in a hierarchical state machine
Return type:: State

property root

Get the root state in a states hierarchy.

Returns:: Root state in the states hierarchy
Return type:: State

set_initial_state(state)

Set an initial state in a state machine.

Parameters:: state (State) – Set this state as initial in a state machine