Subversion Repositories mkgmap

/*
 * Copyright (C) 2010.
 *
 * 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.reader.osm;

import java.util.Collections;
import java.util.Set;

import uk.me.parabola.util.EnhancedProperties;

/**
 * Allows common code to be called during the reading of OSM files in both
 * their XML and binary formats.
 *
 * You should only use this when you need access to other ways or nodes
 * or the IDs of the individual points that go into a way, which are no
 * longer available during conversion.
 *
 * This is the stage before conversion from the node/way/tag format to the
 * general intermediate format. Most operations should be done during that
 * conversion process, which is accessible from the style file language.
 *
 * We also want access to the other ways/nodes to generate sea polygons,
 * cycle lanes and so on.
 *
 * @author Steve Ratcliffe
 */
public interface OsmReadingHooks {

        /**
         * Passes in the element saver and the command line options. The hook code
         * can use the options to set itself up if needed.
         *
         * The saver gives access to the previously saved nodes/ways/relations and
         * also allows you to add extra ways.
         *
         * @param saver This is where all the elements are being collected.  You can access previously added
         * elements from here by their id. You can also add generated elements.  You must not add the
         * element that is being passed in as it will be added automatically.
         *
         * @param props The command line options.
         * @param style The style used for this input file
         *
         * @return If you return false then this set of hooks will not be used. So if they
         * are not needed based on the options supplied you can disable it.
         */
        default boolean init(ElementSaver saver, EnhancedProperties props, Style style) {
                return true;
        }

        /**
         * Retrieves the tags that are used by this hook. Tags that are used only if they are referenced
         * in the style file should not be added to this list.
         *
         * @return the tag names used by this hook
         */
        default Set<String> getUsedTags() {
                return Collections.emptySet();
        }
       
        /**
         * Called on adding a node to the saver and just before it is added. You can modify
         * it, create new nodes etc.
         *
         * @param node The node to be added.
         */
        default void onAddNode(Node node) {}

        /**
         * Add the given way. The way must be complete, call after the end tag
         * is seen for the XML format.
         *
         * @param way The osm way.
         */
        default void onAddWay(Way way) {}

        /**
         * This is called whenever a tagged node is added to a way.  
         *
         * The way will not have been added via addWay() yet.
         * Hooks can change the node and the coord object associated with the id, but they must not remove them.
         *
         * @param way The incomplete way.
         * @param coordId The coordinate id of the node that is being added.
         */
        default void onNodeAddedToWay(Way way, long coordId) {}

        /**
         * Called after the file has been read.  Can be used to add more elements to the saver
         * based on information stored up.
         */
        default void end() {}
       
}