Split out the Soundex algorithm from the metric.

6 files changed, 187 insertions, 100 deletions

diff --git a/core/source/core/scala/org/hashtree/stringmetric/Algorithm.scala b/core/source/core/scala/org/hashtree/stringmetric/Algorithm.scala
new file mode 100755
index 0000000..e334d20
--- /dev/null
+++ b/core/source/core/scala/org/hashtree/stringmetric/Algorithm.scala
@@ -0,0 +1,6 @@
+package org.hashtree.stringmetric
+
+/** Marks those which leverage traits of a stand alone algorithm. */
+trait Algorithm[T, C] {
+	def compute(t: T)(implicit c: C): Option[T]
+}
\ No newline at end of file
diff --git a/core/source/core/scala/org/hashtree/stringmetric/StringAlgorithm.scala b/core/source/core/scala/org/hashtree/stringmetric/StringAlgorithm.scala
new file mode 100755
index 0000000..2901010
--- /dev/null
+++ b/core/source/core/scala/org/hashtree/stringmetric/StringAlgorithm.scala
@@ -0,0 +1,6 @@
+package org.hashtree.stringmetric
+
+/** Marks those which leverage traits of a string based [[org.hashtree.stringmetric.Algorithm]]. */
+trait StringAlgorithm extends Algorithm[String, StringCleaner] {
+	def compute(ca: Array[Char])(implicit stringCleaner: StringCleaner): Option[Array[Char]]
+}
\ No newline at end of file
diff --git a/core/source/core/scala/org/hashtree/stringmetric/phonetic/Soundex.scala b/core/source/core/scala/org/hashtree/stringmetric/phonetic/Soundex.scala
new file mode 100755
index 0000000..75762ca
--- /dev/null
+++ b/core/source/core/scala/org/hashtree/stringmetric/phonetic/Soundex.scala
@@ -0,0 +1,94 @@
+package org.hashtree.stringmetric.phonetic
+
+import org.hashtree.stringmetric.{ StringAlgorithm, StringCleaner, StringCleanerDelegate }
+import scala.annotation.tailrec
+
+/** An implementation of the Soundex [[org.hashtree.stringmetric.StringAlgorithm]]. */
+object Soundex extends StringAlgorithm {
+	override def compute(charArray: Array[Char])(implicit stringCleaner: StringCleaner): Option[Array[Char]] = {
+		val ca = stringCleaner.clean(charArray)
+
+		if (ca.length == 0) None
+		else {
+			letter(ca, 0) match {
+				case Some(l) => {
+					if (ca.length - 1 == l._2) Some(Array(l._1, '0', '0', '0'))
+					else {
+						Some(
+							code(
+								ca.takeRight(ca.length - (l._2 + 1)),
+								l._1, // Pass first letter.
+								Array(l._1) // Pass array with first letter.
+							).padTo(4, '0')
+						)
+					}
+				}
+				case None => None
+			}
+		}
+	}
+
+	override def compute(string: String)(implicit stringCleaner: StringCleaner): Option[String] = {
+		compute(stringCleaner.clean(string.toCharArray))(new StringCleanerDelegate) match {
+			case Some(se) => Some(se.mkString)
+			case None => None
+		}
+	}
+
+	@tailrec
+	private[this] def letter(i: Array[Char], ind: Int): Option[Tuple2[Char, Int]] = {
+		if (i.length == 0) None
+		else {
+			val c = i.head.toLower
+
+			if (c >= 97 && c <= 122) Some((c, ind)) else letter(i.tail, ind + 1)
+		}
+	}
+
+	@tailrec
+	private[this] def code(i: Array[Char], p: Char, o: Array[Char]): Array[Char] = {
+		require(p >= 97 && p <= 122)
+		require(o.length > 0)
+
+		if (i.length == 0) o
+		else {
+			val c = i.head.toLower
+			val m2 = (mc: Char) => mc match {
+				case 'b' | 'f' | 'p' | 'v' => '1'
+				case 'c' | 'g' | 'j' | 'k' | 'q' | 's' | 'x' | 'z' => '2'
+				case 'd' | 't' => '3'
+				case 'l' => '4'
+				case 'm' | 'n' => '5'
+				case 'r' => '6'
+				case _ => '\0'
+			}
+			val m1 = (mc: Char, pc: Char) => mc match {
+				case 'b' | 'f' | 'p' | 'v' if pc != '1' => '1'
+				case 'c' | 'g' | 'j' | 'k' | 'q' | 's' | 'x' | 'z' if pc != '2' => '2'
+				case 'd' | 't' if pc != '3' => '3'
+				case 'l' if pc != '4' => '4'
+				case 'm' | 'n' if pc != '5' => '5'
+				case 'r' if pc != '6' => '6'
+				case _ => '\0'
+			}
+			val a = p match {
+				// Code twice.
+				case 'a' | 'e' | 'i' | 'o' | 'u' | 'y' => m2(c)
+				// Code once.
+				case _ => {
+					m1(
+						c,
+						o.last match {
+							case '1' | '2' | '3' | '4' | '5' | '6' => o.last
+							case _ => m2(o.last)
+						}
+					)
+				}
+			}
+
+			if (o.length == 3 && a != '\0') o :+ a
+			else
+				code(i.tail, c, if (a != '\0') o :+ a else o)
+		}
+	}
+}
\ No newline at end of file
diff --git a/core/source/core/scala/org/hashtree/stringmetric/phonetic/SoundexMetric.scala b/core/source/core/scala/org/hashtree/stringmetric/phonetic/SoundexMetric.scala
index c8f2d13..cc891ab 100755
--- a/core/source/core/scala/org/hashtree/stringmetric/phonetic/SoundexMetric.scala
+++ b/core/source/core/scala/org/hashtree/stringmetric/phonetic/SoundexMetric.scala
@@ -1,100 +1,30 @@
 package org.hashtree.stringmetric.phonetic
 
 import org.hashtree.stringmetric.{ StringCleaner, StringCleanerDelegate, StringMetric }
-import scala.annotation.tailrec
 
 /** An implementation of the Soundex [[org.hashtree.stringmetric.StringMetric]]. */
 object SoundexMetric extends StringMetric {
-	implicit val stringCleaner = new StringCleanerDelegate
-
 	override def compare(charArray1: Array[Char], charArray2: Array[Char])(implicit stringCleaner: StringCleaner): Option[Boolean] = {
 		val ca1 = stringCleaner.clean(charArray1)
 		val ca2 = stringCleaner.clean(charArray2)
-		val se1 = if (ca1.length > 0) soundex(ca1) else None
-		val se2 = if (ca2.length > 0) soundex(ca2) else None
 
-		if (!se1.isDefined || !se2.isDefined) None else Some(se1.get == se2.get)
+		if (ca1.length == 0 || ca2.length == 0) None
+		else {
+			val se1 = Soundex.compute(ca1)
+			val se2 = Soundex.compute(ca2)
+
+			if (!se1.isDefined || !se2.isDefined || (se1.get.length == 0 && se2.get.length == 0))
+				None
+			else
+				Some(se1.get.sameElements(se2.get))
+		}
 	}
 
 	override def compare(string1: String, string2: String)(implicit stringCleaner: StringCleaner): Option[Boolean] = {
+		// Unable to perform simple equality check, due to situations where no letters are passed.
 		compare(
 			stringCleaner.clean(string1.toCharArray),
 			stringCleaner.clean(string2.toCharArray)
 		)(new StringCleanerDelegate)
 	}
-
-	private[this] def soundex(ca: Array[Char]) = {
-		require(ca.length > 0)
-
-		@tailrec
-		def letter(ca: Array[Char], i: Int): Option[Tuple2[Char, Int]] = {
-			require(ca.length > 0)
-
-			val c = ca.head.toLower
-
-			if (c >= 97 && c <= 122) Some((c, i)) else if (ca.length == 1) None else letter(ca.tail, i + 1)
-		}
-
-		@tailrec
-		def code(i: Array[Char], p: Char, o: Array[Char]): Array[Char] = {
-			require(i.length > 0)
-			require(p >= 97 && p <= 122)
-			require(o.length > 0)
-
-			val c = i.head.toLower
-			val m2 = (mc: Char) => mc match {
-				case 'b' | 'f' | 'p' | 'v' => '1'
-				case 'c' | 'g' | 'j' | 'k' | 'q' | 's' | 'x' | 'z' => '2'
-				case 'd' | 't' => '3'
-				case 'l' => '4'
-				case 'm' | 'n' => '5'
-				case 'r' => '6'
-				case _ => '\0'
-			}
-			val m1 = (mc: Char, pc: Char) => mc match {
-				case 'b' | 'f' | 'p' | 'v' if pc != '1' => '1'
-				case 'c' | 'g' | 'j' | 'k' | 'q' | 's' | 'x' | 'z' if pc != '2' => '2'
-				case 'd' | 't' if pc != '3' => '3'
-				case 'l' if pc != '4' => '4'
-				case 'm' | 'n' if pc != '5' => '5'
-				case 'r' if pc != '6' => '6'
-				case _ => '\0'
-			}
-			val a = p match {
-				// Code twice.
-				case 'a' | 'e' | 'i' | 'o' | 'u' | 'y' => m2(c)
-				// Code once.
-				case _ => {
-					m1(
-						c,
-						o.last match {
-							case '1' | '2' | '3' | '4' | '5' | '6' => o.last
-							case _ => m2(o.last)
-						}
-					)
-				}
-			}
-
-			if (i.length == 1 || (o.length == 3 && a != '\0'))
-				if (a != '\0') o :+ a else o
-			else
-				code(i.tail, c, if (a != '\0') o :+ a else o)
-		}
-
-		letter(ca, 0) match {
-			case Some(l) => {
-				if (ca.length - 1 == l._2) Some(l._1 + "000")
-				else {
-					Some(
-						code(
-							ca.takeRight(ca.length - (l._2 + 1)),
-							l._1, // Pass first letter.
-							Array(l._1) // Pass array with first letter.
-						).mkString.padTo(4, '0')
-					)
-				}
-			}
-			case None => None
-		}
-	}
 }
\ No newline at end of file
diff --git a/core/source/test/scala/org/hashtree/stringmetric/phonetic/SoundexMetricSpec.scala b/core/source/test/scala/org/hashtree/stringmetric/phonetic/SoundexMetricSpec.scala
index 6664696..f92f789 100755
--- a/core/source/test/scala/org/hashtree/stringmetric/phonetic/SoundexMetricSpec.scala
+++ b/core/source/test/scala/org/hashtree/stringmetric/phonetic/SoundexMetricSpec.scala
@@ -8,27 +8,28 @@ import org.scalatest.junit.JUnitRunner
 final class SoundexMetricSpec extends ScalaTest {
 	"SoundexMetric" should provide {
 		"compare method" when passed {
-			"valid arguments" should returns {
-				"Boolean indicating matches" in {
-					SoundexMetric.compare("abc", "abc").get should be (true) // a120 vs. a120
-					SoundexMetric.compare("a", "a").get should be (true) // a000 vs. a000
-					SoundexMetric.compare("abc", "xyz").get should be (false) // a120 vs. x200
+			"empty arguments" should returns {
+				"None" in {
 					SoundexMetric.compare("", "").isDefined should be (false)
+					SoundexMetric.compare("abc", "").isDefined should be (false)
+					SoundexMetric.compare("", "xyz").isDefined should be (false)
+				}
+			}
+			"non-phonetic arguments" should returns {
+				"None" in {
 					SoundexMetric.compare("123", "123").isDefined should be (false)
-					SoundexMetric.compare("1", "1").isDefined should be (false)
-
-					SoundexMetric.compare("Robert", "Rupert").get should be (true) // r163 vs. r163
-					SoundexMetric.compare("Robert", "Rubin").get should be (false) // r163 vs. r150
-
-					SoundexMetric.compare("Ashcraft", "Ashcroft").get should be (true) // a261 vs. a261
-					SoundexMetric.compare("Tymczak", "Tymczak").get should be (true) // t522 vs. t522
-					SoundexMetric.compare("Pfister", "Pfister").get should be (true) // p236 vs. p236
-					SoundexMetric.compare("Euler", "Ellery").get should be (true) // e460 vs. e460
-					SoundexMetric.compare("Gauss", "Ghosh").get should be (true) // g200 vs. g200
-					SoundexMetric.compare("Hilbert", "Heilbronn").get should be (true) // h416 vs. h416
-					SoundexMetric.compare("Knuth", "Kant").get should be (true) // k530 vs. k530
-					SoundexMetric.compare("Lloyd", "Ladd").get should be (true) // l300 vs. l300
-					SoundexMetric.compare("Lukasiewicz", "Lissajous").get should be (true) // l222 vs. l222
+					SoundexMetric.compare("123", "").isDefined should be (false)
+					SoundexMetric.compare("", "123").isDefined should be (false)
+				}
+			}
+			"phonetically similar arguments" should returns {
+				"Boolean indicating true" in {
+					SoundexMetric.compare("robert", "rupert").get should be (true)
+				}
+			}
+			"phonetically dissimilar arguments" should returns {
+				"Boolean indicating false" in {
+					SoundexMetric.compare("robert", "rubin").get should be (false)
 				}
 			}
 		}
diff --git a/core/source/test/scala/org/hashtree/stringmetric/phonetic/SoundexSpec.scala b/core/source/test/scala/org/hashtree/stringmetric/phonetic/SoundexSpec.scala
new file mode 100755
index 0000000..13c6bdd
--- /dev/null
+++ b/core/source/test/scala/org/hashtree/stringmetric/phonetic/SoundexSpec.scala
@@ -0,0 +1,50 @@
+package org.hashtree.stringmetric.phonetic
+
+import org.hashtree.stringmetric.ScalaTest
+import org.junit.runner.RunWith
+import org.scalatest.junit.JUnitRunner
+
+@RunWith(classOf[JUnitRunner])
+final class SoundexSpec extends ScalaTest {
+	"Soundex" should provide {
+		"compute method" when passed {
+			"empty argument" should returns {
+				"None" in {
+					Soundex.compute("").isDefined should be (false)
+				}
+			}
+			"non-phonetic argument" should returns {
+				"None" in {
+					Soundex.compute("123").isDefined should be (false)
+				}
+			}
+			"phonetic argument" should returns {
+				"Some" in {
+					Soundex.compute("abc").get should equal ("a120")
+					Soundex.compute("xyz").get should equal ("x200")
+					Soundex.compute("robert").get should equal ("r163")
+					Soundex.compute("rupert").get should equal ("r163")
+					Soundex.compute("rubin").get should equal ("r150")
+					Soundex.compute("ashcraft").get should equal ("a261")
+					Soundex.compute("tymczak").get should equal ("t522")
+					Soundex.compute("pfister").get should equal ("p236")
+					Soundex.compute("euler").get should equal ("e460")
+					Soundex.compute("gauss").get should equal ("g200")
+					Soundex.compute("hilbert").get should equal ("h416")
+					Soundex.compute("knuth").get should equal ("k530")
+					Soundex.compute("lloyd").get should equal ("l300")
+					Soundex.compute("lukasiewicz").get should equal ("l222")
+					Soundex.compute("ashcroft").get should equal ("a261")
+					Soundex.compute("tymczak").get should equal ("t522")
+					Soundex.compute("pfister").get should equal ("p236")
+					Soundex.compute("ellery").get should equal ("e460")
+					Soundex.compute("ghosh").get should equal ("g200")
+					Soundex.compute("heilbronn").get should equal ("h416")
+					Soundex.compute("kant").get should equal ("k530")
+					Soundex.compute("ladd").get should equal ("l300")
+					Soundex.compute("lissajous").get should equal ("l222")
+				}
+			}
+		}
+	}
+}
\ No newline at end of file