/*
* Copyright 2004-2023 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (https://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.bnf;
import java.util.HashMap;
/**
* Represents an optional BNF rule.
*/
public class RuleOptional implements Rule {
private final Rule rule;
private boolean mapSet;
public RuleOptional(Rule rule) {
this.rule = rule;
}
@Override
public void accept(BnfVisitor visitor) {
if (rule instanceof RuleList) {
RuleList ruleList = (RuleList) rule;
if (ruleList.or) {
visitor.visitRuleOptional(ruleList.list);
return;
}
}
visitor.visitRuleOptional(rule);
}
@Override
public void setLinks(HashMap<String, RuleHead> ruleMap) {
if (!mapSet) {
rule.setLinks(ruleMap);
mapSet = true;
}
}
@Override
public boolean autoComplete(Sentence sentence) {
sentence.stopIfRequired();
rule.autoComplete(sentence);
return true;
}
@Override
public String toString() {
return '[' + rule.toString() + ']';
}
}