roslib/src/actionlib/Goal.js

The standard ROS Javascript Library

/**
 * @fileOverview
 * @author Russell Toris - rctoris@wpi.edu
 */

var Message = require('../core/Message');
var EventEmitter2 = require('eventemitter2').EventEmitter2;

/**
 * An actionlib goal goal is associated with an action server.
 *
 * Emits the following events:
 *  * 'timeout' - if a timeout occurred while sending a goal
 *
 *  @constructor
 *  @param object with following keys:
 *   * actionClient - the ROSLIB.ActionClient to use with this goal
 *   * goalMessage - The JSON object containing the goal for the action server
 */
function Goal(options) {
  var that = this;
  this.actionClient = options.actionClient;
  this.goalMessage = options.goalMessage;
  this.isFinished = false;

  // Used to create random IDs
  var date = new Date();

  // Create a random ID
  this.goalID = 'goal_' + Math.random() + '_' + date.getTime();
  // Fill in the goal message
  this.goalMessage = new Message({
    goal_id : {
      stamp : {
        secs : 0,
        nsecs : 0
      },
      id : this.goalID
    },
    goal : this.goalMessage
  });

  this.on('status', function(status) {
    that.status = status;
  });

  this.on('result', function(result) {
    that.isFinished = true;
    that.result = result;
  });

  this.on('feedback', function(feedback) {
    that.feedback = feedback;
  });

  // Add the goal
  this.actionClient.goals[this.goalID] = this;
}

Goal.prototype.__proto__ = EventEmitter2.prototype;

/**
 * Send the goal to the action server.
 *
 * @param timeout (optional) - a timeout length for the goal's result
 */
Goal.prototype.send = function(timeout) {
  var that = this;
  that.actionClient.goalTopic.publish(that.goalMessage);
  if (timeout) {
    setTimeout(function() {
      if (!that.isFinished) {
        that.emit('timeout');
      }
    }, timeout);
  }
};

/**
 * Cancel the current goal.
 */
Goal.prototype.cancel = function() {
  var cancelMessage = new Message({
    id : this.goalID
  });
  this.actionClient.cancelTopic.publish(cancelMessage);
};

module.exports = Goal;