Fixes #864: Adds text similarity/distance methods and double metaphon…

…e text encoding.

- Added Apache commons-text dependency

- Added Levenshtein Similarity code and test

- Added Hamming Distance code and test

- Added Jaro-Winkler Distance code and test

- Added Double Metaphone text encoding and test

build.gradle

@@ -127,6 +127,7 @@ dependencies {
     compile group: 'com.github.javafaker', name: 'javafaker', version: '0.10'
 
     compile group: 'org.apache.commons', name: 'commons-math3', version: '3.6.1'
+    compile group: 'org.apache.commons', name: 'commons-text', version: '1.2'
     jmh group: 'org.neo4j', name: 'neo4j-lucene-index', version: neo4jVersionEffective
     jmh group: 'org.neo4j', name: 'neo4j-kernel', version: neo4jVersionEffective, classifier: "tests"
 

src/main/java/apoc/text/Phonetic.java

@@ -1,5 +1,6 @@
 package apoc.text;
 
+import org.apache.commons.codec.language.DoubleMetaphone;
 import org.neo4j.procedure.Description;
 import apoc.result.LongResult;
 import apoc.result.StringResult;
@@ -18,6 +19,8 @@
 
 public class Phonetic {
 
+    private static final DoubleMetaphone DOUBLE_METAPHONE = new DoubleMetaphone();
+
     @Procedure
     @Description("apoc.text.phonetic(value) yield value - Compute the US_ENGLISH phonetic soundex encoding of all words of the text value which can be a single string or a list of strings")
     public Stream<StringResult> phonetic(final @Name("value") Object value) {
@@ -38,6 +41,17 @@ public Stream<PhoneticResult> phoneticDelta(final @Name("text1") String text1, f
         }
     }
 
+    @Procedure
+    @Description("apoc.text.doubleMetaphone(value) yield value - Compute the Double Metaphone phonetic encoding of all words of the text value which can be a single string or a list of strings")
+    public Stream<StringResult> doubleMetaphone(final @Name("value") Object value)
+    {
+        Stream<Object> stream = value instanceof Iterable ? StreamSupport.stream(((Iterable) value).spliterator(), false) : Stream.of(value);
+
+        return stream.map(str -> (str == null || str.toString().isEmpty()) ? StringResult.EMPTY :
+                                 new StringResult(Stream.of(str.toString().trim().split("\\W+"))
+                                         .map(DOUBLE_METAPHONE::doubleMetaphone).reduce("", (a, s) -> a + s)));
+    }
+
     public static class PhoneticResult {
         public final String phonetic1, phonetic2;
         public final long delta;

src/main/java/apoc/text/Strings.java

@@ -1,6 +1,9 @@
 package apoc.text;
 
 import apoc.util.Util;
+import org.apache.commons.text.similarity.HammingDistance;
+import org.apache.commons.text.similarity.JaroWinklerDistance;
+import org.apache.commons.text.similarity.LevenshteinDistance;
 import org.neo4j.graphdb.Node;
 import org.neo4j.graphdb.Relationship;
 import org.neo4j.helpers.collection.Pair;
@@ -36,6 +39,10 @@
  */
 public class Strings {
 
+    private final static HammingDistance hammingDistance = new HammingDistance();
+    private final static JaroWinklerDistance jaroWinklerDistance = new JaroWinklerDistance();
+    private final static LevenshteinDistance levenshteinDistance = new LevenshteinDistance();
+
     @UserFunction
     @Description("apoc.text.replace(text, regex, replacement) - replace each substring of the given string that matches the given regular expression with the given replacement.")
     public String replace(final @Name("text") String text, final @Name("regex") String regex, final @Name("replacement") String replacement) {
@@ -126,12 +133,45 @@ public boolean compareCleaned(final @Name("text1") String text1, final @Name("te
     }
 
     @UserFunction
-    @Description("apoc.text.distance(text1, text2) - compare the given strings with the StringUtils.distance(text1, text2) method")
+    @Description("apoc.text.distance(text1, text2) - compare the given strings with the Levenshtein distance algorithm.")
     public Long distance(final @Name("text1") String text1, @Name("text2")final String text2) {
         if (text1 == null || text2 == null) {
             return null;
         }
-        return (long) StringUtils.getLevenshteinDistance(text1, text2);
+        return (long)levenshteinDistance.apply(text1, text2);
+    }
+
+    @UserFunction
+    @Description( "apoc.text.levenshteinSimilarity(text1, text2) - calculate the similarity (a value within 0 and 1) between two texts." )
+    public Double similarity(final @Name("text1") String text1, @Name("text2")final String text2) {
+        if ( text1 == null || text2 == null ) {
+            return null;
+        }
+
+        int longerLength = Math.max(text1.length(), text2.length());
+        if (longerLength == 0) {
+            return 1.0;
+        }
+        long editDistance = distance( text1, text2 );
+        return (longerLength - editDistance) / (double)longerLength;
+    }
+
+    @UserFunction
+    @Description( "apoc.text.hammingDistance(text1, text2) - compare the given strings with the Hamming distance algorithm." )
+    public Long hammingDistance(final @Name("text1") String text1, @Name("text2")final String text2) {
+        if (text1 == null || text2 == null) {
+            return null;
+        }
+        return (long)hammingDistance.apply(text1, text2) ;
+    }
+
+    @UserFunction
+    @Description( "apoc.text.jaroWinklerDistance(text1, text2) - compare the given strings with the Jaro-Winkler distance algorithm." )
+    public Double jaroWinklerDistance(final @Name("text1") String text1, @Name("text2")final String text2) {
+        if (text1 == null || text2 == null) {
+            return null;
+        }
+        return jaroWinklerDistance.apply(text1, text2);
     }
 
     @UserFunction

src/test/java/apoc/text/PhoneticTest.java

@@ -75,4 +75,32 @@ public void shouldComputeSoundexDifference() {
                 assertThat(row.get("delta"), equalTo(4L))
         );
     }
+
+    @Test
+    public void shoudlComputeDoubleMetaphone() {
+        testCall(db, "CALL apoc.text.doubleMetaphone('Apoc')", (row) ->
+                assertThat(row.get("value"), equalTo("APK"))
+        );
+    }
+
+    @Test
+    public void shoudlComputeDoubleMetaphoneOfNull() {
+        testCall(db, "CALL apoc.text.doubleMetaphone(NULL)", (row) ->
+                assertThat(row.get("value"), equalTo(null))
+        );
+    }
+
+    @Test
+    public void shoudlComputeDoubleMetaphoneForTheEmptyString() {
+        testCall(db, "CALL apoc.text.doubleMetaphone('')", (row) ->
+                assertThat(row.get("value"), equalTo(null))
+        );
+    }
+
+    @Test
+    public void shouldComputeDoubleMetaphoneOfManyWords() {
+        testCall(db, "CALL apoc.text.doubleMetaphone('Hello, dear User!')", (row) ->
+                assertThat(row.get("value"), equalTo("HLTRASR"))
+        );
+    }
 }

src/test/java/apoc/text/StringsTest.java

@@ -190,15 +190,45 @@ public void testCompareCleanedInQuery() throws Exception {
     }
 
     @Test
-    public void testGetLevenshteinDistance() {
+    public void testLevenshteinDistance() {
         String text1 = "Levenshtein";
         String text2 = "Levenstein";
 
-        testCall(db, "RETURN apoc.text.distance({a}, {b}) as distance",
+        testCall(db, "RETURN apoc.text.distance({a}, {b}) AS distance",
             map("a", text1, "b", text2),
             row -> assertEquals(1L, row.get("distance")));
     }
 
+    @Test
+    public void testLevenshteinSimilarity() {
+        String text1 = "Levenshtein";
+        String text2 = "Levenstein";
+
+        testCall(db, "RETURN apoc.text.similarity({a}, {b}) AS similarity",
+                map("a", text1, "b", text2),
+                row -> assertEquals(0.9, (double)row.get("similarity"), 0.01));
+    }
+
+    @Test
+    public void testHammingDistance() {
+        String text1 = "Neo";
+        String text2 = "Leo";
+
+        testCall(db, "RETURN apoc.text.hammingDistance({a}, {b}) AS distance",
+                map("a", text1, "b", text2),
+                row -> assertEquals(1L, row.get("distance")));
+    }
+
+    @Test
+    public void testJaroWinklerDistance() {
+        String text1 = "Neo";
+        String text2 = "Leo";
+
+        testCall(db, "RETURN apoc.text.jaroWinklerDistance({a}, {b}) AS distance",
+                map("a", text1, "b", text2),
+                row -> assertEquals(0.7777, (double)row.get("distance"), 0.0001));
+    }
+
     @Test
     public void testFuzzyMatch() {
         Strings strings = new Strings();