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-rw-r--r--scalding/src/main/scala/sandcrawler/StringUtilities.scala76
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diff --git a/scalding/src/main/scala/sandcrawler/StringUtilities.scala b/scalding/src/main/scala/sandcrawler/StringUtilities.scala
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+package sandcrawler
+
+import java.text.Normalizer
+import java.util.regex.Pattern
+
+object StringUtilities {
+ // bnewbold: I propose that we:
+ // 1. keep only \p{Ideographic}, \p{Alphabetic}, and \p{Digit}
+ // 2. strip accents
+ // 3. "lower-case" (unicode-aware)
+ // 4. do any final custom/manual mappings
+ //
+ // We should check (test) that null bytes are handled, in addition to other
+ // more obvious characters
+
+ // Adapted from https://git-wip-us.apache.org/repos/asf?p=commons-lang.git;a=blob;f=src/main/java/org/apache/commons/lang3/StringUtils.java;h=1d7b9b99335865a88c509339f700ce71ce2c71f2;hb=HEAD#l934
+ def removeAccents(s : String) : String = {
+ val replacements = Map(
+ '\u0141' -> 'L',
+ '\u0142' -> 'l', // Letter ell
+ '\u00d8' -> 'O',
+ '\u00f8' -> 'o'
+ )
+ val sb = new StringBuilder(Normalizer.normalize(s, Normalizer.Form.NFD))
+ for (i <- 0 to sb.length - 1) {
+ for (key <- replacements.keys) {
+ if (sb(i) == key) {
+ sb.deleteCharAt(i);
+ sb.insert(i, replacements(key))
+ }
+ }
+ }
+ val pattern = Pattern.compile("\\p{InCombiningDiacriticalMarks}+")
+ pattern.matcher(sb).replaceAll("")
+ }
+
+ // Source: https://stackoverflow.com/a/30076541/631051
+ def removePunctuation(s: String) : String = {
+ s.replaceAll("""[\p{Punct}]""", "")
+ }
+
+ // Adapted from: https://stackoverflow.com/a/16018452/631051
+ def similarity(s1a : String, s2a : String) : Double = {
+ val (s1, s2) = (removeAccents(removePunctuation(s1a)),
+ removeAccents(removePunctuation(s2a)))
+ val longer : String = if (s1.length > s2.length) s1 else s2
+ val shorter : String = if (s1.length > s2.length) s2 else s1
+ if (longer.length == 0) {
+ // Both strings are empty.
+ 1
+ } else {
+ (longer.length - stringDistance(longer, shorter)) / longer.length.toDouble
+ }
+ }
+
+ // Source: https://oldfashionedsoftware.com/2009/11/19/string-distance-and-refactoring-in-scala/
+ def stringDistance(s1: String, s2: String): Int = {
+ val memo = scala.collection.mutable.Map[(List[Char],List[Char]),Int]()
+ def min(a:Int, b:Int, c:Int) = Math.min( Math.min( a, b ), c)
+ def sd(s1: List[Char], s2: List[Char]): Int = {
+ if (!memo.contains((s1, s2))) {
+ memo((s1,s2)) = (s1, s2) match {
+ case (_, Nil) => s1.length
+ case (Nil, _) => s2.length
+ case (c1::t1, c2::t2) =>
+ min( sd(t1,s2) + 1, sd(s1,t2) + 1,
+ sd(t1,t2) + (if (c1==c2) 0 else 1) )
+ }
+ }
+ memo((s1,s2))
+ }
+
+ sd( s1.toList, s2.toList )
+ }
+}
+