1 // component.hxx - Base class for autopilot components
3 // Written by Torsten Dreyer
4 // Based heavily on work created by Curtis Olson, started January 2004.
6 // Copyright (C) 2004 Curtis L. Olson - http://www.flightgear.org/~curt
7 // Copyright (C) 2010 Torsten Dreyer - Torsten (at) t3r (dot) de
9 // This program is free software; you can redistribute it and/or
10 // modify it under the terms of the GNU General Public License as
11 // published by the Free Software Foundation; either version 2 of the
12 // License, or (at your option) any later version.
14 // This program is distributed in the hope that it will be useful, but
15 // WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 // General Public License for more details.
19 // You should have received a copy of the GNU General Public License
20 // along with this program; if not, write to the Free Software
21 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
23 #ifndef __COMPONENT_HXX
24 #define __COMPONENT_HXX 1
30 #include <simgear/structure/subsystem_mgr.hxx>
31 #include <simgear/props/propsfwd.hxx>
33 namespace FGXMLAutopilot {
36 * @brief Base class for other autopilot components
38 class Component : public SGSubsystem {
42 SGSharedPtr<const SGCondition> _condition;
43 SGPropertyNode_ptr _enable_prop;
44 std::string * _enable_value;
50 virtual bool configure( SGPropertyNode& cfg_node,
51 const std::string& cfg_name,
52 SGPropertyNode& prop_root );
55 * @brief the implementation of the update() method of the SGSubsystem
57 virtual void update( double dt );
60 * @brief pure virtual function to be implemented by the derived classes. Gets called from
61 * the update method if it's not disabled with the firstTime parameter set to true if this
62 * is the first call after being enabled
63 * @param firstTime set to true if this is the first update call since this component has
64 been enabled. Set to false for every subsequent call.
65 * @param dt the elapsed time since the last call
67 virtual void update( bool firstTime, double dt ) = 0;
70 * @brief overideable method being called from the update() method if this component
71 * is disabled. It's a noop by default.
73 virtual void disabled( double dt ) {}
76 * @brief debug flag, true if this component should generate some useful output
83 * @brief a (historic) flag signalling the derived class that it should compute it's internal
84 * state but shall not set the output properties if /autopilot/locks/passive-mode is true.
91 * @brief A constructor for an empty Component.
96 * virtual destructor to clean up resources
101 * @brief configure this component from a property node. Iterates through
102 * all nodes found as children under configNode and calls configure
103 * of the derived class for each child.
105 * @param prop_root Property root for all relative paths
106 * @param cfg Property node containing the configuration
108 virtual bool configure( SGPropertyNode& prop_root,
109 SGPropertyNode& cfg );
112 * @brief getter for the name property
113 * @return the name of the component
115 inline const std::string& get_name() const { return _name; }
118 * @brief setter for the name property
119 * @param name the name of the component
121 inline void set_name( const std::string & name ) { _name = name; }
124 * @brief check if this component is enabled as configured in the
125 * <enable> section
126 * @return true if the enable-condition is true.
128 * If a <condition> is defined, this condition is evaluated,
129 * <prop> and <value> tags are ignored.
131 * If a <prop> is defined and no <value> is defined, the property
132 * named in the <prop><prop> tags is evaluated as boolean.
134 * If a <prop> is defined and a <value> is defined, the property named
135 * in <prop></prop> is compared (as a string) to the value defined in
136 * <value></value>
138 * Returns true, if neither <condition> nor <prop> exists
140 bool isPropertyEnabled();
145 #endif // COMPONENT_HXX