#53 Allow to ack emits

Also allow use of isOnlyWholeWords, isOnlyWholeWordsWhiteSpaceSeparated
and isAllowOverlaps using a StatefulEmitHandler

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

@@ -4,6 +4,7 @@ import org.ahocorasick.interval.IntervalTree;
 import org.ahocorasick.interval.Intervalable;
 import org.ahocorasick.trie.handler.DefaultEmitHandler;
 import org.ahocorasick.trie.handler.EmitHandler;
+import org.ahocorasick.trie.handler.StatefulEmitHandler;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -103,10 +104,13 @@ public class Trie {
         return new MatchToken(text.substring(emit.getStart(), emit.getEnd() + 1), emit);
     }
 
-    @SuppressWarnings("unchecked")
     public Collection<Emit> parseText(final CharSequence text) {
-        final DefaultEmitHandler emitHandler = new DefaultEmitHandler();
-        parseText(text, emitHandler);
+        return parseText(text, new DefaultEmitHandler());
+    }
+
+    @SuppressWarnings("unchecked")
+    public Collection<Emit> parseText(final CharSequence text, final StatefulEmitHandler emitHandler) {
+        parseText(text, (EmitHandler) emitHandler);
 
         final List<Emit> collectedEmits = emitHandler.getEmits();
 
@@ -281,8 +285,8 @@ public class Trie {
         // TODO: The check for empty might be superfluous.
         if (emits != null && !emits.isEmpty()) {
             for (final String emit : emits) {
-                emitHandler.emit(new Emit(position - emit.length() + 1, position, emit));
-                emitted = true;
+                emitted = emitHandler.emit(new Emit(position - emit.length() + 1, position, emit)) || emitted;
+                if(emitted && trieConfig.isStopOnHit()) break;
             }
         }
 

src/main/java/org/ahocorasick/trie/handler/DefaultEmitHandler.java

@@ -5,15 +5,17 @@ import org.ahocorasick.trie.Emit;
 import java.util.ArrayList;
 import java.util.List;
 
-public class DefaultEmitHandler implements EmitHandler {
+public class DefaultEmitHandler implements StatefulEmitHandler {
 
     private final List<Emit> emits = new ArrayList<>();
 
     @Override
-    public void emit(final Emit emit) {
+    public boolean emit(final Emit emit) {
         this.emits.add(emit);
+        return true;
     }
 
+    @Override
     public List<Emit> getEmits() {
         return this.emits;
     }

src/main/java/org/ahocorasick/trie/handler/EmitHandler.java

@@ -3,5 +3,5 @@ package org.ahocorasick.trie.handler;
 import org.ahocorasick.trie.Emit;
 
 public interface EmitHandler {
-    void emit(Emit emit);
+    boolean emit(Emit emit);
 }

src/main/java/org/ahocorasick/trie/handler/StatefulEmitHandler.java

@@ -0,0 +1,9 @@
+package org.ahocorasick.trie.handler;
+
+import java.util.List;
+
+import org.ahocorasick.trie.Emit;
+
+public interface StatefulEmitHandler extends EmitHandler {
+    List<Emit> getEmits();
+}

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

@@ -1,6 +1,7 @@
 package org.ahocorasick.trie;
 
 import org.ahocorasick.trie.handler.EmitHandler;
+import org.ahocorasick.trie.handler.StatefulEmitHandler;
 import org.junit.Test;
 
 import java.util.ArrayList;
@@ -97,9 +98,43 @@ public class TrieTest {
                 .stopOnHit()
                 .build();
         Collection<Emit> emits = trie.parseText("ushers");
-        assertEquals(2, emits.size()); // she @ 3, he @ 3, hers @ 5
+        assertEquals(1, emits.size()); // she @ 3, he @ 3, hers @ 5
         Iterator<Emit> iterator = emits.iterator();
         checkEmit(iterator.next(), 2, 3, "he");
+    }
+
+    @Test
+    public void ushersTestStopOnHitSkipOne() {
+        Trie trie = Trie.builder()
+                .addKeywords(PRONOUNS)
+                .stopOnHit()
+                .build();
+        
+        StatefulEmitHandler testEmitHandler = new StatefulEmitHandler() {
+            private final List<Emit> emits = new ArrayList<>();
+            boolean first = true;
+
+            @Override
+            public boolean emit(final Emit emit) {
+                if(first) {
+                    // return false for the first element
+                    first = false;
+                    return false;
+                }
+                this.emits.add(emit);
+                return true;
+            }
+
+            @Override
+            public List<Emit> getEmits() {
+                return this.emits;
+            }
+        };
+        
+        trie.parseText("ushers", testEmitHandler);
+        Collection<Emit> emits = testEmitHandler.getEmits();
+        assertEquals(1, emits.size()); // she @ 3, he @ 3, hers @ 5
+        Iterator<Emit> iterator = emits.iterator();
         checkEmit(iterator.next(), 1, 3, "she");
     }
 
@@ -152,8 +187,9 @@ public class TrieTest {
         EmitHandler emitHandler = new EmitHandler() {
 
             @Override
-            public void emit(Emit emit) {
+            public boolean emit(Emit emit) {
                 emits.add(emit);
+                return true;
             }
         };
         trie.parseText("ushers", emitHandler);