package jadex.rules.rulesystem;
import jadex.rules.state.IOAVState;
/**
* Rule system is a container for state, rule base,
* and pattern matcher with agenda.
*/
public class RuleSystem
{
//-------- attributes --------
/** The working memory containing all facts. */
protected IOAVState state;
/** The rule base containing all the rules. */
protected IRulebase rulebase;
/** The pattern matcher functionality for evaluating rules. */
protected IPatternMatcherFunctionality matcherfunc;
/** The matcher state. */
protected IPatternMatcherState matcherstate;
/** Flag to check if the rule system was already initialized. */
protected boolean inited;
//-------- constructors --------
/**
* Create a new rule system.
*/
public RuleSystem(IOAVState state, IRulebase rulebase, IPatternMatcherFunctionality matcherfunc)
{
this(state, rulebase, matcherfunc, new FIFOAgenda());
}
/**
* Create a new rule system.
*/
public RuleSystem(IOAVState state, IRulebase rulebase, IPatternMatcherFunctionality matcherfunc, AbstractAgenda agenda)
{
this.state = state;
this.rulebase = rulebase;
this.matcherfunc = matcherfunc;
this.matcherstate = matcherfunc.createMatcherState(state, agenda);
}
//-------- methods --------
/**
* Initialize the rule system.
* The rule system needs to be initialized once, before
* rules can be fired.
* When trying to initialize the rule system twice, an exception is thrown.
* Exceptions are also thrown, when trying to fire rules of a not yet
* initialized rule system
*/
public void init()
{
if(inited)
throw new RuntimeException("Cannot initialize already initialized rule system.");
this.inited = true;
// Initialize matcher with existing objects.
matcherstate.init();
}
/**
* Get the memory.
* @return The memory.
*/
public IOAVState getState()
{
return state;
}
/**
* Get the rulebase.
* @return The rulebase.
*/
public IRulebase getRulebase()
{
return rulebase;
}
/**
* Get the agenda.
* The agenda can only be accessed, after the rule system
* has been initialized with {@link#init()}.
* @return The agenda.
*/
public IAgenda getAgenda()
{
// This is a convenience check for users, which forget to init().
if(!inited)
throw new RuntimeException("Cannot access agenda before rule system is inited.");
return matcherstate.getAgenda();
}
/**
* Fire all rules until quiescence.
*/
public void fireAllRules()
{
IAgenda agenda = getAgenda();
state.notifyEventListeners();
do
{
agenda.fireRule();
state.expungeStaleObjects();
state.notifyEventListeners();
}
while(!agenda.isEmpty());
}
//-------- internal methods --------
/**
* Get the matcher functionality.
* @return The matcher functionality.
*/
public IPatternMatcherFunctionality getMatcherFunctionality()
{
return matcherfunc;
}
/**
* Get the matcher state.
* @return The matcher state.
*/
public IPatternMatcherState getMatcherState()
{
return matcherstate;
}
}