Subversion Repositories mkgmap

/*
 * Copyright (C) 2012.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 3 or
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 */

package uk.me.parabola.mkgmap.osmstyle.function;

import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;
import java.util.HashSet;
import java.util.Locale;
import java.util.Map.Entry;
import java.util.Set;

import uk.me.parabola.mkgmap.reader.osm.Element;
import uk.me.parabola.mkgmap.reader.osm.Relation;
import uk.me.parabola.mkgmap.reader.osm.Way;
import uk.me.parabola.mkgmap.scan.SyntaxException;

/**
 * Calculates the length of a way or a relation in meter. The length of a
 * relation is defined as the sum of its member lengths.
 *
 * @author WanMil
 */
public class LengthFunction extends CachedFunction {
        private final DecimalFormat nf = new DecimalFormat("0.0#####################", DecimalFormatSymbols.getInstance(Locale.US));

        public LengthFunction() {
                super(null);
        }

        protected String calcImpl(Element el) {
                return nf.format(calcLength(el, new HashSet<>()));
        }
       
        private static double calcLength(Element el, Set<Element> visited) {
                if (el == null || visited.contains(el))
                        return 0; // don't add length again
                visited.add(el);
                if (el instanceof Way) {
                        return ((Way) el).calcLengthInMetres();
                } else if (el instanceof Relation) {
                        Relation rel = (Relation) el;
                        double length = 0;
                        for (Entry<String, Element> relElem : rel.getElements()) {
                                if (relElem.getValue() instanceof Way || relElem.getValue() instanceof Relation) {
                                        length += calcLength(relElem.getValue(), visited);
                                }
                        }
                        return length;
                } else {
                        throw new SyntaxException("length() cannot calculate elements of type "+el.getClass().getName());
                }
        }
       
        @Override
        public String getName() {
                return "length";
        }

        @Override
        public boolean supportsWay() {
                return true;
        }

        @Override
        public boolean supportsRelation() {
                return true;
        }
       
        @Override
        public int getComplexity() {
                return 2;
        }
}