Created HammingMetric, spec, and command.

4 files changed, 56 insertions, 2 deletions

diff --git a/core/source/core/scala/org/hashtree/stringmetric/HammingMetric.scala b/core/source/core/scala/org/hashtree/stringmetric/HammingMetric.scala
new file mode 100755
index 0000000..67fd3e5
--- /dev/null
+++ b/core/source/core/scala/org/hashtree/stringmetric/HammingMetric.scala
@@ -0,0 +1,25 @@
+package org.hashtree.stringmetric
+
+/** An implementation of the Hamming [[org.hashtree.stringmetric.StringMetric]]. */
+object HammingMetric extends StringMetric {
+	override def compare(charArray1: Array[Char], charArray2: Array[Char])(implicit stringCleaner: StringCleaner): Option[Int] = {
+		if (charArray1.length == 0 || charArray2.length == 0 || charArray2.length != charArray2.length)
+			None
+		else
+			Some(hamming(stringCleaner.clean(charArray1), stringCleaner.clean(charArray2)))
+	}
+
+	override def compare(string1: String, string2: String)(implicit stringCleaner: StringCleaner): Option[Int] = {
+		compare(stringCleaner.clean(string1.toCharArray),
+			stringCleaner.clean(string2.toCharArray)
+		)(new StringCleanerDelegate)
+	}
+
+	private[this] def hamming(ca1: Array[Char], ca2: Array[Char]) = {
+		require(ca1.length > 0)
+		require(ca2.length > 0)
+		require(ca1.length == ca2.length)
+
+		ca1.zip(ca2).count(t => t._1 != t._2)
+	}
+}
\ No newline at end of file
diff --git a/core/source/core/scala/org/hashtree/stringmetric/JaroMetric.scala b/core/source/core/scala/org/hashtree/stringmetric/JaroMetric.scala
index bd2b468..fb9a3e4 100755
--- a/core/source/core/scala/org/hashtree/stringmetric/JaroMetric.scala
+++ b/core/source/core/scala/org/hashtree/stringmetric/JaroMetric.scala
@@ -30,7 +30,9 @@ object JaroMetric extends StringMetric {
 		// Return 1 if strings are an exact match.
 		if (string1.length > 0 && string1 == string2) return Some(1f)
 
-		compare(stringCleaner.clean(string1.toCharArray), stringCleaner.clean(string2.toCharArray))(new StringCleanerDelegate)
+		compare(stringCleaner.clean(string1.toCharArray),
+			stringCleaner.clean(string2.toCharArray)
+		)(new StringCleanerDelegate)
 	}
 
 	private[this] def `match`(ct: CompareTuple) = {
diff --git a/core/source/core/scala/org/hashtree/stringmetric/JaroWinklerMetric.scala b/core/source/core/scala/org/hashtree/stringmetric/JaroWinklerMetric.scala
index 892da04..8292c55 100755
--- a/core/source/core/scala/org/hashtree/stringmetric/JaroWinklerMetric.scala
+++ b/core/source/core/scala/org/hashtree/stringmetric/JaroWinklerMetric.scala
@@ -24,6 +24,8 @@ object JaroWinklerMetric extends StringMetric {
 		// Return 1 if strings are an exact match.
 		if (string1.length > 0 && string1 == string2) return Some(1f)
 
-		compare(stringCleaner.clean(string1.toCharArray), stringCleaner.clean(string2.toCharArray))(new StringCleanerDelegate)
+		compare(stringCleaner.clean(string1.toCharArray),
+			stringCleaner.clean(string2.toCharArray)
+		)(new StringCleanerDelegate)
 	}
 }
\ No newline at end of file
diff --git a/core/source/test/scala/org/hashtree/stringmetric/HammingMetricSpec.scala b/core/source/test/scala/org/hashtree/stringmetric/HammingMetricSpec.scala
new file mode 100755
index 0000000..641bbde
--- /dev/null
+++ b/core/source/test/scala/org/hashtree/stringmetric/HammingMetricSpec.scala
@@ -0,0 +1,25 @@
+package org.hashtree.stringmetric
+
+import org.junit.runner.RunWith
+import org.scalatest.junit.JUnitRunner
+
+@RunWith(classOf[JUnitRunner])
+final class HammingMetricSpec extends ScalaTest {
+	"HammingMetric" should provide {
+		"compare method" when passed {
+			"valid arguments" should returns {
+				"Int indicating distance" in {
+					HammingMetric.compare("", "").isDefined should be (false)
+					HammingMetric.compare("abc", "").isDefined should be (false)
+					HammingMetric.compare("", "xyz").isDefined should be (false)
+
+					HammingMetric.compare("abc", "abc").get should be (0)
+					HammingMetric.compare("abc", "xyz").get should be (3)
+					HammingMetric.compare("toned", "roses").get should be (3)
+					HammingMetric.compare("1011101", "1001001").get should be (2)
+					HammingMetric.compare("2173896", "2233796").get should be (3)
+				}
+			}
+		}
+	}
+}
\ No newline at end of file