wait_state.py

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#!/usr/bin/env python

import rospy
from flexbe_core import EventState
from rospy.exceptions import ROSInterruptException

'''
Created on 15.06.2013

@author: David Conner
'''

class WaitState(EventState):
        '''
        Implements a state that can be used to wait on timed process.

        -- wait_time    float   Amount of time to wait in seconds.

        <= done                                 Indicates that the wait time has elapsed.

        '''
        def __init__(self, wait_time):
                '''Constructor'''
                super(WaitState, self).__init__(outcomes=['done'])
                self._wait = wait_time

                
        def execute(self, userdata):
                '''Execute this state'''

                elapsed = rospy.get_rostime() - self._start_time;
                if (elapsed.to_sec() > self._wait):
                        return 'done'

        
        def on_enter(self, userdata):
                '''Upon entering the state, save the current time and start waiting.'''

                self._start_time = rospy.get_rostime()
                
                try:
                        self._rate.sleep()
                except ROSInterruptException:
                        rospy.logwarn('Skipped sleep.')