package org.drools.rule.builder;
import org.drools.lang.descr.BaseDescr;
import org.drools.lang.descr.ConditionalBranchDescr;
import org.drools.lang.descr.EvalDescr;
import org.drools.lang.descr.NamedConsequenceDescr;
import org.drools.rule.ConditionalBranch;
import org.drools.rule.EvalCondition;
import org.drools.rule.GroupElement;
import org.drools.rule.NamedConsequence;
import org.drools.rule.Pattern;
import org.drools.rule.RuleConditionElement;
import java.util.List;
public class ConditionalBranchBuilder implements RuleConditionBuilder {
public ConditionalBranch build(RuleBuildContext context, BaseDescr descr) {
return build( context, descr, null );
}
public ConditionalBranch build(RuleBuildContext context, BaseDescr descr, Pattern prefixPattern) {
ConditionalBranchDescr conditionalBranch = (ConditionalBranchDescr) descr;
RuleConditionBuilder evalBuilder = (RuleConditionBuilder) context.getDialect().getBuilder( EvalDescr.class );
EvalCondition condition = (EvalCondition) evalBuilder.build(context, conditionalBranch.getCondition(), getLastPattern(context));
NamedConsequenceBuilder namedConsequenceBuilder = (NamedConsequenceBuilder) context.getDialect().getBuilder( NamedConsequenceDescr.class );
NamedConsequence consequence = namedConsequenceBuilder.build(context, conditionalBranch.getConsequence());
ConditionalBranchDescr elseBranchDescr = conditionalBranch.getElseBranch();
return new ConditionalBranch( condition, consequence, elseBranchDescr != null ? build(context, elseBranchDescr, prefixPattern) : null );
}
private Pattern getLastPattern(RuleBuildContext context) {
GroupElement ge = (GroupElement)context.getBuildStack().peek();
List<RuleConditionElement> siblings = ge.getChildren();
for (int i = siblings.size()-1; i >= 0; i--) {
RuleConditionElement element = siblings.get(i);
if (element instanceof Pattern) {
return (Pattern) element;
}
}
throw new RuntimeException("Cannot find a Pattern in the RuleBuildContext");
}
}