source: josm/src/org/openstreetmap/josm/data/osm/visitor/AllNodesVisitor.java@ 159

package org.openstreetmap.josm.data.osm.visitor;

import java.util.Collection;
import java.util.HashSet;

import org.openstreetmap.josm.data.osm.Segment;
import org.openstreetmap.josm.data.osm.Node;
import org.openstreetmap.josm.data.osm.OsmPrimitive;
import org.openstreetmap.josm.data.osm.Way;

/**
 * Collect all nodes a specific osm primitive has.
 * 
 * @author imi
 */
public class AllNodesVisitor implements Visitor {

        /**
         * The resulting nodes collected so far.
         */
        public Collection<Node> nodes = new HashSet<Node>();

        /**
         * Nodes have only itself as nodes.
         */
        public void visit(Node n) {
                nodes.add(n);
        }

        /**
         * Line segments have exactly two nodes: from and to.
         */
        public void visit(Segment ls) {
                if (!ls.incomplete) {
                        visit(ls.from);
                        visit(ls.to);
                }
        }

        /**
         * Ways have all nodes from their segments.
         */
        public void visit(Way w) {
                for (Segment ls : w.segments)
                        visit(ls);
        }

        /**
         * @return All nodes the given primitive has.
         */
        public static Collection<Node> getAllNodes(Collection<? extends OsmPrimitive> osms) {
                AllNodesVisitor v = new AllNodesVisitor();
                for (OsmPrimitive osm : osms)
                        osm.visit(v);
                return v.nodes;
        }
}