001// License: GPL. See LICENSE file for details.
002package org.openstreetmap.josm.data.validation.tests;
003
004import static java.util.regex.Pattern.CASE_INSENSITIVE;
005import static java.util.regex.Pattern.UNICODE_CASE;
006import static org.openstreetmap.josm.tools.I18n.tr;
007
008import java.awt.geom.Point2D;
009import java.util.ArrayList;
010import java.util.Arrays;
011import java.util.HashMap;
012import java.util.List;
013import java.util.Map;
014import java.util.regex.Matcher;
015import java.util.regex.Pattern;
016
017import org.openstreetmap.josm.data.osm.OsmPrimitive;
018import org.openstreetmap.josm.data.osm.Way;
019import org.openstreetmap.josm.data.validation.Severity;
020import org.openstreetmap.josm.data.validation.Test;
021import org.openstreetmap.josm.data.validation.TestError;
022import org.openstreetmap.josm.data.validation.util.ValUtil;
023import org.openstreetmap.josm.gui.progress.ProgressMonitor;
024import org.openstreetmap.josm.tools.MultiMap;
025import org.openstreetmap.josm.tools.Utils;
026
027/**
028 * Checks for similar named ways, symptom of a possible typo. It uses the
029 * Levenshtein distance to check for similarity
030 *
031 * @author frsantos
032 */
033public class SimilarNamedWays extends Test {
034
035    protected static final int SIMILAR_NAMED = 701;
036
037    /** All ways, grouped by cells */
038    private Map<Point2D,List<Way>> cellWays;
039    /** The already detected errors */
040    private MultiMap<Way, Way> errorWays;
041
042    private ArrayList<NormalizeRule> rules = new ArrayList<NormalizeRule>();
043
044    /**
045     * Constructor
046     */
047    public SimilarNamedWays() {
048        super(tr("Similarly named ways"),
049                tr("This test checks for ways with similar names that may have been misspelled."));
050
051        // FIXME: hardcode these rules for now. Replace them with preferences later
052        // See https://josm.openstreetmap.de/ticket/3733#comment:19
053        addRegExprRule("\\d+", "0"); // Highway 66
054        addRegExprRule("\\d+(st|nd|rd|th)", "0st"); // 3rd Ave
055        addRegExprRule("^[A-Z] ", "X"); // E Street
056        addSynonyms("east", "west", "north", "south");
057        addSynonyms("first", "second", "third");
058    }
059
060    @Override
061    public void startTest(ProgressMonitor monitor) {
062        super.startTest(monitor);
063        cellWays = new HashMap<>(1000);
064        errorWays = new MultiMap<>();
065    }
066
067    @Override
068    public void endTest() {
069        cellWays = null;
070        errorWays = null;
071        super.endTest();
072    }
073
074    @Override
075    public void visit(Way w) {
076        if (!w.isUsable())
077            return;
078
079        String name = w.get("name");
080        if (name == null || name.length() < 6)
081            return;
082
083        List<List<Way>> theCellWays = ValUtil.getWaysInCell(w, cellWays);
084        for (List<Way> ways : theCellWays) {
085            for (Way w2 : ways) {
086                if (errorWays.contains(w, w2) || errorWays.contains(w2, w)) {
087                    continue;
088                }
089
090                String name2 = w2.get("name");
091                if (name2 == null || name2.length() < 6) {
092                    continue;
093                }
094
095                if (similaryName(name, name2)) {
096                    List<OsmPrimitive> primitives = new ArrayList<>(2);
097                    primitives.add(w);
098                    primitives.add(w2);
099                    errors.add(new TestError(this, Severity.WARNING, tr("Similarly named ways"), SIMILAR_NAMED, primitives));
100                    errorWays.put(w, w2);
101                }
102            }
103            ways.add(w);
104        }
105    }
106
107    /**
108     * Compute Levenshtein distance
109     *
110     * @param s First word
111     * @param t Second word
112     * @return The distance between words
113     */
114    public static int getLevenshteinDistance(String s, String t) {
115        int[][] d; // matrix
116        int n; // length of s
117        int m; // length of t
118        int i; // iterates through s
119        int j; // iterates through t
120        char s_i; // ith character of s
121        char t_j; // jth character of t
122        int cost; // cost
123
124        // Step 1
125        n = s.length();
126        m = t.length();
127        if (n == 0)
128            return m;
129        if (m == 0)
130            return n;
131        d = new int[n + 1][m + 1];
132
133        // Step 2
134        for (i = 0; i <= n; i++) {
135            d[i][0] = i;
136        }
137        for (j = 0; j <= m; j++) {
138            d[0][j] = j;
139        }
140
141        // Step 3
142        for (i = 1; i <= n; i++) {
143
144            s_i = s.charAt(i - 1);
145
146            // Step 4
147            for (j = 1; j <= m; j++) {
148
149                t_j = t.charAt(j - 1);
150
151                // Step 5
152                if (s_i == t_j) {
153                    cost = 0;
154                } else {
155                    cost = 1;
156                }
157
158                // Step 6
159                d[i][j] = Utils.min(d[i - 1][j] + 1, d[i][j - 1] + 1, d[i - 1][j - 1] + cost);
160            }
161        }
162
163        // Step 7
164        return d[n][m];
165    }
166
167    /**
168     * Add a regular expression rule.
169     * @param regExpr the regular expression to search for
170     * @param replacement a string to replace with, which should match the expression.
171     */
172    public void addRegExprRule(String regExpr, String replacement) {
173        rules.add(new RegExprRule(regExpr, replacement));
174    }
175
176    /**
177     * Add a rule with synonym words.
178     * @param words words which are synonyms
179     */
180    public void addSynonyms(String... words) {
181        for (String word : words) {
182            rules.add(new SynonymRule(word, words));
183        }
184    }
185
186    /**
187     * Check if two names are similar, but not identical. First both names will be "normalized".
188     * Afterwards the Levenshtein distance will be calculated.<br>
189     * Examples for normalization rules:<br>
190     * <code>replaceAll("\\d+", "0")</code><br>
191     * would cause similaryName("track 1", "track 2") = false, but similaryName("Track 1", "track 2") = true
192     * @param name first name to compare
193     * @param name2 second name to compare
194     * @return true if the normalized names are different but only a "little bit"
195     */
196    public boolean similaryName(String name, String name2) {
197        // check plain strings
198        int distance = getLevenshteinDistance(name, name2);
199        boolean similar = distance>0 && distance<=2;
200
201        // try all rules
202        for (NormalizeRule rule : rules) {
203            int levenshteinDistance = getLevenshteinDistance(rule.normalize(name), rule.normalize(name2));
204            if (levenshteinDistance == 0)
205                // one rule results in identical names: identical
206                return false;
207            else if (levenshteinDistance <= 2) {
208                // 0 < distance <= 2
209                similar = true;
210            }
211        }
212        return similar;
213    }
214
215    public interface NormalizeRule {
216
217        /**
218         * Normalize the string by replacing parts.
219         * @param name name to normalize
220         * @return normalized string
221         */
222        String normalize(String name);
223    }
224
225    public class RegExprRule implements NormalizeRule {
226        private final Pattern regExpr;
227        private final String replacement;
228
229        public RegExprRule(String expression, String replacement) {
230            this.regExpr = Pattern.compile(expression);
231            this.replacement = replacement;
232        }
233
234        @Override
235        public String normalize(String name) {
236            return regExpr.matcher(name).replaceAll(replacement);
237        }
238
239        @Override
240        public String toString() {
241            return "replaceAll(" + regExpr + ", " + replacement + ")";
242        }
243    }
244
245    public class SynonymRule implements NormalizeRule {
246
247        private final String[] words;
248        private final Pattern regExpr;
249        private final String replacement;
250
251        public SynonymRule(String replacement, String[] words) {
252            this.replacement = replacement.toLowerCase();
253            this.words = words;
254
255            // build regular expression for other words (for fast match)
256            StringBuilder expression = new StringBuilder();
257            int maxLength = 0;
258            for (int i = 0; i < words.length; i++) {
259                if (words[i].length() > maxLength) {
260                    maxLength = words[i].length();
261                }
262                if (expression.length() > 0) {
263                    expression.append("|");
264                }
265                expression.append(Pattern.quote(words[i]));
266            }
267            this.regExpr = Pattern.compile(expression.toString(), CASE_INSENSITIVE + UNICODE_CASE);
268        }
269
270        @Override
271        public String normalize(String name) {
272            // find first match
273            Matcher matcher = regExpr.matcher(name);
274            if (!matcher.find())
275                return name;
276
277            int start = matcher.start();
278
279            // which word matches?
280            String part = "";
281            for (int i = 0; i < words.length; i++) {
282                String word = words[i];
283                part = name.substring(start, start + word.length());
284                if (word.equalsIgnoreCase(part)) {
285                    break;
286                }
287            }
288
289            // replace the word
290            char[] newName = matcher.replaceFirst(replacement).toCharArray();
291
292            // adjust case (replacement is not shorter than matching word!)
293            int minLength = Math.min(replacement.length(), part.length());
294            for (int i = 0; i < minLength; i++) {
295                if (Character.isUpperCase(part.charAt(i))) {
296                    newName[start + i] = Character.toUpperCase(newName[start + i]);
297                }
298            }
299
300            return new String(newName);
301        }
302
303        @Override
304        public String toString() {
305            return "synonyms(" + replacement + ", " + Arrays.toString(words) + ")";
306        }
307    }
308}