/**
* Sets the goal for the rule-sets supplied.
* @param A goal with the name of a rule-set and parameters.
* @return true if the goal can be met by a rule-set.
*/
public bool setGoal(EmptyElement goal)
{
if (m_ruleSets == null || m_ruleSets.Count == 0)
{
m_log.writeEltTime("fail");
m_log.writeAttr("rule-set", "none");
m_log.endElt();
return(false);
}
if (m_goal == null && goal == null)
{
m_log.writeEltTime("fail");
m_log.writeAttr("goal", "none");
m_log.endElt();
return(false);
}
if (goal != null)
{
m_goal = goal; // overwrite m_goal
}
else
{
goal = m_goal;
}
m_log.writeEltTime("new-goal");
goal.log();
m_log.endElt();
string name = goal.getName();
foreach (RuleSet rs in m_ruleSets)
{
if (name.Equals(rs.getName()))
{
m_ruleSet = rs; break;
} // skip the rest of the rule-sets
}
if (m_ruleSet == null)
{
m_log.writeEltTime("fail");
m_log.writeAttr("goal", "no rule-set can solve");
m_log.endElt();
return(false);
}
m_substitutes = new ArrayList(2);
for (int p = 0; p < m_ruleSet.formals(); p++)
{ // goal attributes are named the same as rule-set parameters
string paramName = m_ruleSet.getParameterName(p);
string value = goal.getValue(paramName);
string formal = m_ruleSet.getParameterValue(p);
m_substitutes.Add(new Substitute(formal, value));
}
m_rules = m_ruleSet.getRules(); // use the active rule set
return(true);
}
/**
* Write this Rule to the Log.
* @param markTime if true, log with time stamp
* @param markActions if false, don't log actions.
* @param substitutes List of formal parameters and their new values.
*/
private void log(bool markTime, bool markActions, ArrayList substitutes)
{
Log log = Log.getOnly();
if (markTime)
{
log.writeEltTime("rule");
}
else
{
log.writeElt("rule");
}
log.writeAttr("id", m_id);
if (m_desc != null)
{
log.writeAttr("desc", m_desc);
}
log.writeElt("when");
foreach (EmptyElement w in m_when)
{
EmptyElement copyEl = w.SubstituteCopy(substitutes);
copyEl.log();
}
log.endElt(); // </when>
if (markActions)
{
foreach (EmptyElement a in m_actions)
{
a.log();
}
}
log.endElt(); // </rule>
}
/**
* Sets the goal for the rule-sets supplied.
* @param A goal with the name of a rule-set and parameters.
* @return true if the goal can be met by a rule-set.
*/
public bool setGoal(EmptyElement goal)
{
if (m_ruleSets == null || m_ruleSets.Count == 0)
{
m_log.writeEltTime("fail");
m_log.writeAttr("rule-set","none");
m_log.endElt();
return false;
}
if (m_goal == null && goal == null)
{
m_log.writeEltTime("fail");
m_log.writeAttr("goal","none");
m_log.endElt();
return false;
}
if (goal != null) m_goal = goal; // overwrite m_goal
else goal = m_goal;
m_log.writeEltTime("new-goal");
goal.log();
m_log.endElt();
string name = goal.getName();
foreach (RuleSet rs in m_ruleSets)
{ if (name.Equals(rs.getName()))
{ m_ruleSet = rs; break; } // skip the rest of the rule-sets
}
if (m_ruleSet == null)
{
m_log.writeEltTime("fail");
m_log.writeAttr("goal","no rule-set can solve");
m_log.endElt();
return false;
}
m_substitutes = new ArrayList(2);
for (int p = 0; p < m_ruleSet.formals(); p++)
{ // goal attributes are named the same as rule-set parameters
string paramName = m_ruleSet.getParameterName(p);
string value = goal.getValue(paramName);
string formal = m_ruleSet.getParameterValue(p);
m_substitutes.Add(new Substitute(formal,value));
}
m_rules = m_ruleSet.getRules(); // use the active rule set
return true;
}
/**
* Perform goal-driven actions based on sensor readings.
* Performance continues until a "done" action is encountered.
* Performance may be interrupted if a "fail" action,
* runtime error or timeout occurs.
* Rule order is important. Rules are evaluated in order.
* The most difficult to evaluate should be the first rule,
* the easiest to satisfy, the last.
* @return true if the "done" action is reached, otherwise false.
*/
public bool act()
{
bool alive = true;
bool result = false;
Rule lastFired = null;
while (alive)
{ // evaluate the rules in order.
// the same rule can not fire twice in a row
foreach (Rule rule in m_rules)
{
if (rule.evaluate(m_sensors, m_substitutes))
{ // fire: get the rule's actions
if (rule == lastFired && !rule.isFireAlways())
{
break;
} // skip the rest of the rules
lastFired = rule;
rule.logCondition(true, m_substitutes);
ArrayList actions = rule.getActions();
// foreach action:
foreach (EmptyElement act in actions)
{ // log the action.
EmptyElement action = act.SubstituteCopy(m_substitutes);
action.log(true);
// if it is a sensact action, consume it
string name = action.getName();
if (name.Equals("done"))
{
return(true);
}
if (name.Equals("fail"))
{
return(false);
}
// if (name.Equals("try")) {}
// if (name.Equals("lookup")) {}
// if (name.Equals("log")) {}
// does the action activate another rule-set?
RuleSet ActivateRs = null;
foreach (RuleSet rs in m_ruleSets)
{
if (name.Equals(rs.getName()))
{
ActivateRs = rs; break;
} // skip the rest of the rule-sets
}
if (ActivateRs != null)
{ // instantiate another Sensact to use the rule-set
// suspend this rule-set, activate rs.
result = doSubGoal(ActivateRs, action);
alive = result;
}
else
{ // otherwise, send it to the appliction to exectue
result = m_actions.doAction(action);
alive = result;
}
if (!alive)
{
break;
}
} // end of for each action
break; // skip the rest of the rules
} // end of if rule fired
} // end for each rule
}
return(result);
}
