Subversion Repositories splitter

/*
 * Copyright (c) 2011,2012, Gerd Petermann
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 3 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.splitter;

import java.awt.Rectangle;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;

/**
 * Maps a set containing the used areas to an int value.  
 * An OSM element is written to one or more areas. Every used
 * combination of areas is translated to an int.
 * @author Gerd Petermann
 *
 */
public class AreaDictionary {
        private static final int DICT_START = Short.MAX_VALUE;
        private final Area[] areas;
        private final ArrayList<AreaSet> sets;
        private final int numOfAreas;
        private final HashMap<AreaSet, Integer> index;
        private final HashSet<AreaSet> simpleNeighbours = new HashSet<>();
        private final int overlapAmount;
       
        /**
         * Create a dictionary for a given array of areas.
         * @param overlapAmount
         * @param areas the array of areas
         */
        AreaDictionary(List<Area> areas, int overlapAmount){
                this.areas = areas.toArray(new Area[areas.size()]);
                this.overlapAmount = overlapAmount;
                this.numOfAreas = areas.size();
                sets = new ArrayList<>();
                index = new HashMap<>(areas.size() * 4, 0.5f);
                init();
        }
       
        /**
         * Initialize the dictionary with sets containing a single area.
         */
        private void init() {
                ArrayList<Rectangle> rectangles = new ArrayList<>(numOfAreas);
                ArrayList<AreaSet> areaSets = new ArrayList<>(numOfAreas);
                for (int i = 0; i < numOfAreas; i++) {
                        AreaSet b = new AreaSet(i);
                        translate(b);
                        rectangles.add(Utils.area2Rectangle(areas[i], 0));
                        areaSets.add(b);
                }
                findSimpleNeigbours(rectangles, areaSets);
                System.out.println("cached " + simpleNeighbours.size() + " combinations of areas that form rectangles.");
        }
       
        /**
         * Calculate the int value for a given AreaSet. The AreaSet must not
         * contain values higher than numOfAreas.
         * @param areaSet the AreaSet
         * @return an Integer value that identifies this AreaSet, never null
         */
        public Integer translate(final AreaSet areaSet) {
                Integer combiIndex = index.get(areaSet);
                if (combiIndex == null) {
                        combiIndex = (sets.size() - DICT_START);
                        if (combiIndex == Integer.MAX_VALUE) {
                                throw new SplitFailedException("areaDictionary is full. Try to decrease number of areas.");
                        }
                        AreaSet set = new AreaSet(areaSet);
                        set.lock();
                        sets.add(set);
                        index.put(set, combiIndex);
                        if (sets.size() % 1000 == 0)
                                System.out.println("dictionary contains now " + Utils.format(sets.size()) + " entries");
                }
                return combiIndex;
        }

        /**
         * Find those areas that build rectangles when they are
         * added together. A way or relation that lies exactly within
         * such a combination cannot cross other areas.
         * @param rectangles
         * @param areaSets
         */
        private void findSimpleNeigbours(ArrayList<Rectangle> rectangles, ArrayList<AreaSet> areaSets){
                ArrayList<Rectangle> newRectangles = new ArrayList<>();
                ArrayList<AreaSet> newAreaSets = new ArrayList<>();
               
                for (int i = 0; i < rectangles.size(); i++) {
                        Rectangle r1 = rectangles.get(i);
                        for (int j = i + 1; j < rectangles.size(); j++) {
                                Rectangle r2 = rectangles.get(j);
                                boolean isSimple = r1.y == r2.y && r1.height == r2.height
                                                && (r1.x == r2.getMaxX() || r2.x == r1.getMaxX())
                                                || (r1.x == r2.x && r1.width == r2.width && (r1.y == r2.getMaxY() || r2.y == r1.getMaxY()));
                                if (isSimple) {
                                        AreaSet simpleNeighbour = new AreaSet(areaSets.get(i));
                                        simpleNeighbour.or(areaSets.get(j));
                                        if (simpleNeighbour.cardinality() <= 10 && !simpleNeighbours.contains(simpleNeighbour)) {
                                                simpleNeighbours.add(simpleNeighbour);
                                                Rectangle pair = new Rectangle(r1);
                                                pair.add(r2);
                                                newRectangles.add(pair);
                                                newAreaSets.add(simpleNeighbour);
                                        }
                                }
                        }
                }
                if (!newRectangles.isEmpty()) {
                        rectangles.addAll(newRectangles);
                        areaSets.addAll(newAreaSets);
                        newRectangles = null;
                        newAreaSets = null;
                        if (simpleNeighbours.size() < 1000)
                                findSimpleNeigbours(rectangles, areaSets);
                }
        }
       
        /**
         * Return the AreaSet that is related to the int value.
         * The caller must make sure that the index is valid.
         * @param idx a value that was returned by the translate() method.  
         * @return the AreaSet
         */
        public AreaSet getSet(final int idx) {
                return sets.get(DICT_START + idx);
        }
       

        /**
         * return the number of sets in this dictionary
         * @return the number of sets in this dictionary
         */
        public int size() {
                return sets.size();
        }

        public int getNumOfAreas() {
                return numOfAreas;
        }

        public boolean mayCross(AreaSet areaSet) {
                return !simpleNeighbours.contains(areaSet);
        }
       
        public Area getArea(int idx) {
                return areas[idx];
        }

        public Area getExtendedArea(int idx) {
                Area bounds = areas[idx];
                if (overlapAmount == 0)
                        return bounds;
                return new Area(bounds.getMinLat() - overlapAmount,
                                bounds.getMinLong() - overlapAmount,
                                bounds.getMaxLat() + overlapAmount,
                                bounds.getMaxLong() + overlapAmount);
        }

        public List<Area> getAreas() {
                return Collections.unmodifiableList(Arrays.asList(areas));
        }

        public static int translate(int singleWriterId) {
                return (singleWriterId - DICT_START);
        }
}