java_cup.runtime.SyntaxTreeDFS Maven / Gradle / Ivy

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A fork of the Java Cup parser generator with some bug fixes and enhancements. (Forked at version 11b)

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package java_cup.runtime;

import java.util.HashMap;
import java.util.List;

public class SyntaxTreeDFS {
    public static interface ElementHandler {
        public void handle(XMLElement parent, List children);
    }

    public static abstract class AbstractVisitor implements Visitor {
        private HashMap preMap = new HashMap<>();
        private HashMap postMap = new HashMap<>();

        public abstract void defaultPre(XMLElement element, List children);

        public abstract void defaultPost(XMLElement element, List children);

        @Override
        public void preVisit(XMLElement element) {
            ElementHandler handler = preMap.get(element.tagname);
            if (handler == null) {
                defaultPre(element, element.getChildren());
            } else
                handler.handle(element, element.getChildren());
        }

        @Override
        public void postVisit(XMLElement element) {
            ElementHandler handler = postMap.get(element.tagname);
            if (handler == null) {
                defaultPost(element, element.getChildren());
            } else
                handler.handle(element, element.getChildren());
        }

        public void registerPreVisit(String s, ElementHandler h) {
            preMap.put(s, h);
        }

        public void registerPostVisit(String s, ElementHandler h) {
            postMap.put(s, h);
        }
    }

    public static interface Visitor {
        public void preVisit(XMLElement element);

        public void postVisit(XMLElement element);
    }

    public static void dfs(XMLElement element, Visitor visitor) {
        visitor.preVisit(element);
        for (XMLElement el : element.getChildren()) {
            dfs(el, visitor);
        }
        visitor.postVisit(element);
    }
}