Issue #3 added case insensitivity when matching keywords

README.md

@@ -90,6 +90,21 @@ If you want the algorithm to only check for whole words, you can tell the Trie t
 In this case, it will only find one match, whereas it would normally find four. The sugarcane/canesugar words
 are discarded because they are partial matches.
 
+Some text are WrItTeN in combinations of lowercase and uppercase and therefore hard to identify. You can instruct
+the Trie to lowercase the entire searchtext to ease the matching process.
+
+```java
+    Trie trie = new Trie().caseInsensitive();
+    trie.addKeyword("casing");
+    Collection<Emit> emits = trie.parseText("CaSiNg");
+```
+
+Normally, this match would not be found. With the caseInsensitive settings the entire search text is lowercased
+before the matching begins. Therefore it will find exactly one match. Since you still have control of the original
+search text and you will know exactly where the match was, you can still utilize the original casing.
+
+Now, let's tie it all together. Say, you have this
+
 
 
 License

pom.xml

@@ -78,8 +78,8 @@
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-compiler-plugin</artifactId>
                 <configuration>
-                    <source>1.6</source>
-                    <target>1.6</target>
+                    <source>1.7</source>
+                    <target>1.7</target>
                 </configuration>
             </plugin>
 

src/main/java/org/ahocorasick/trie/Trie.java

@@ -31,6 +31,11 @@ public class Trie {
         this(new TrieConfig());
     }
 
+    public Trie caseInsensitive() {
+        this.trieConfig.setCaseInsensitive(true);
+        return this;
+    }
+
     public Trie removeOverlaps() {
         this.trieConfig.setAllowOverlaps(false);
         return this;
@@ -42,7 +47,6 @@ public class Trie {
     }
 
     public void addKeyword(String keyword) {
-
         State currentState = this.rootState;
         for (Character character : keyword.toCharArray()) {
             currentState = currentState.addState(character);
@@ -54,6 +58,10 @@ public class Trie {
     public Collection<Emit> parseText(String text) {
         checkForConstructedFailureStates();
 
+        if (trieConfig.isCaseInsensitive()) {
+            text = text.toLowerCase();
+        }
+
         int position = 0;
         State currentState = this.rootState;
         List<Emit> collectedEmits = new ArrayList<Emit>();
@@ -80,9 +88,9 @@ public class Trie {
         List<Emit> removeEmits = new ArrayList<Emit>();
         for (Emit emit : collectedEmits) {
             if ((emit.getStart() == 0 ||
-                 searchText.charAt(emit.getStart() - 1) == ' ') &&
+                 !Character.isAlphabetic(searchText.charAt(emit.getStart() - 1))) &&
                 (emit.getEnd() == size ||
-                 searchText.charAt(emit.getEnd() + 1) == ' ')) {
+                 !Character.isAlphabetic(searchText.charAt(emit.getEnd() + 1)))) {
                 continue;
             }
             removeEmits.add(emit);

src/main/java/org/ahocorasick/trie/TrieConfig.java

@@ -6,6 +6,8 @@ public class TrieConfig {
 
     private boolean onlyWholeWords = false;
 
+    private boolean caseInsensitive = false;
+
     public boolean isAllowOverlaps() {
         return allowOverlaps;
     }
@@ -22,4 +24,11 @@ public class TrieConfig {
         this.onlyWholeWords = onlyWholeWords;
     }
 
+    public boolean isCaseInsensitive() {
+        return caseInsensitive;
+    }
+
+    public void setCaseInsensitive(boolean caseInsensitive) {
+        this.caseInsensitive = caseInsensitive;
+    }
 }

src/test/java/org/ahocorasick/trie/TrieTest.java

@@ -135,6 +135,22 @@ public class TrieTest {
         checkEmit(emits.iterator().next(), 20, 24, "sugar");
     }
 
+    @Test
+    public void caseInsensitive() {
+        Trie trie = new Trie().caseInsensitive();
+        trie.addKeyword("turning");
+        trie.addKeyword("once");
+        trie.addKeyword("again");
+        trie.addKeyword("börkü");
+        Collection<Emit> emits = trie.parseText("TurninG OnCe AgAiN BÖRKÜ"); // left, middle, right test
+        assertEquals(4, emits.size()); // Match must not be made
+        Iterator<Emit> it = emits.iterator();
+        checkEmit(it.next(), 0, 6, "turning");
+        checkEmit(it.next(), 8, 11, "once");
+        checkEmit(it.next(), 13, 17, "again");
+        checkEmit(it.next(), 19, 23, "börkü");
+    }
+
     private void checkEmit(Emit next, int expectedStart, int expectedEnd, String expectedKeyword) {
         assertEquals(expectedStart, next.getStart());
         assertEquals(expectedEnd, next.getEnd());