/// <summary> Here is a description of the compilation algorithm.
/// 1. iterate over the conditional elements
/// i. generate the alpha nodes
/// a. literal constraints generate alpha node
/// b. predicate constaints that compare against a literal generate alpha node
/// ii. calculate the bindings
/// a. each binding has a rowId
/// b. NOT and EXIST CE do not increment the rowId
/// 2. iterate over the conditional elements
/// i. generate the beta nodes
/// ii. attach the Left Input adapater nodes
/// iii. attach the join nodes to the alpha nodes
/// 3. create the terminal node and attach to the last
/// join node.
///
/// This means the rule compiler takes a 2 pass approach to
/// compiling rules. At the start of the method, it sets 3
/// attributes to null: prevCE, prevJoinNode, joinNode.
/// Those attributes are used by the compile join methods,
/// so it's important to set it to null at the start. If
/// we don't the Current rule won't compile correctly.
/// </summary>
public virtual bool addRule(Rule.IRule rule)
{
rule.resolveTemplates(engine);
if (!validate || (validate && tval.analyze(rule) == Analysis_Fields.VALIDATION_PASSED))
{
// we have to set the attributes to null, before we start compiling a rule.
// we've set the attributes to null, so we can compile now!!
if (rule.Conditions != null && rule.Conditions.Length > 0)
{
// we check the name of the rule to see if it is for a specific
// module. if it is, we have to Add it to that module
Module = rule;
try
{
ICondition[] conds = rule.Conditions;
// first we create the constraints, before creating the Conditional
// elements which include joins
// we use a counter and only increment it to make sure the
// row index of the bindings are accurate. this makes it simpler
// for the rule compiler and compileJoins is cleaner and does
// less work.
int counter = 0;
for (int idx = 0; idx < conds.Length; idx++)
{
ICondition con = conds[idx];
// compile object conditions
//implement in the ObjectConditionCompiler.compile or ExistConditionCompiler.compile
con.getCompiler(this).compile(con, counter, rule, rule.RememberMatch);
if ((con is ObjectCondition) && (!((ObjectCondition) con).Negated))
{
counter++;
}
}
// now we compile the joins
compileJoins(rule);
BaseNode last = rule.LastNode;
TerminalNode tnode = createTerminalNode(rule);
attachTerminalNode(last, tnode);
// compile the actions
compileActions(rule, rule.Actions);
// now we pass the bindings to the rule, so that actiosn can
// resolve the bindings
// now we Add the rule to the module
currentMod.addRule(rule);
CompileMessageEventArgs ce = new CompileMessageEventArgs(rule, EventType.ADD_RULE_EVENT);
ce.Rule = rule;
notifyListener(ce);
return true;
}
catch (AssertException e)
{
CompileMessageEventArgs ce = new CompileMessageEventArgs(rule, EventType.INVALID_RULE);
ce.Message = Messages.getString("RuleCompiler.assert.error"); //$NON-NLS-1$
notifyListener(ce);
TraceLogger.Instance.Debug(e);
return false;
}
}
else if (rule.Conditions.Length == 0)
{
Module = rule;
// the rule has no LHS, this means it only has actions
BaseNode last = (BaseNode) inputnodes.Get(engine.initFact);
TerminalNode tnode = createTerminalNode(rule);
compileActions(rule, rule.Actions);
attachTerminalNode(last, tnode);
// now we Add the rule to the module
currentMod.addRule(rule);
CompileMessageEventArgs ce = new CompileMessageEventArgs(rule, EventType.ADD_RULE_EVENT);
ce.Rule = rule;
notifyListener(ce);
return true;
}
return false;
}
else
{
// we need to print out a message saying the rule was not valid
ISummary error = tval.Errors;
engine.writeMessage("Rule " + rule.Name + " was not added. ", Constants.DEFAULT_OUTPUT); //$NON-NLS-1$ //$NON-NLS-2$
engine.writeMessage(error.Message, Constants.DEFAULT_OUTPUT);
ISummary warn = tval.Warnings;
engine.writeMessage(warn.Message, Constants.DEFAULT_OUTPUT);
return false;
}
}
