Issue #23 added callback handler concept which omits the custom setting up of a list, but instead places direct calls to the handler. The handler are only supported on the lowest level of aho-corasick, ie no overlap, whole words and token support

Also added the possibility to pass a reader to the same level as above.

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

@@ -2,6 +2,9 @@ package org.ahocorasick.trie;
 
 import org.ahocorasick.interval.IntervalTree;
 import org.ahocorasick.interval.Intervalable;
+import org.ahocorasick.trie.configuration.ParseConfiguration;
+import org.ahocorasick.trie.handler.DefaultEmitHandler;
+import org.ahocorasick.trie.handler.EmitHandler;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -87,19 +90,12 @@ public class Trie {
 
     @SuppressWarnings("unchecked")
     public Collection<Emit> parseText(String text) {
-        checkForConstructedFailureStates();
+        DefaultEmitHandler emitHandler = new DefaultEmitHandler();
+        parseText(new ParseConfiguration()
+                .setEmitHandler(emitHandler)
+                .setText(text));
 
-        int position = 0;
-        State currentState = this.rootState;
-        List<Emit> collectedEmits = new ArrayList<Emit>();
-        for (Character character : text.toCharArray()) {
-            if (trieConfig.isCaseInsensitive()) {
-                character = Character.toLowerCase(character);
-            }
-            currentState = getState(currentState, character);
-            storeEmits(position, currentState, collectedEmits);
-            position++;
-        }
+        List<Emit> collectedEmits = emitHandler.getEmits();
 
         if (trieConfig.isOnlyWholeWords()) {
             removePartialMatches(text, collectedEmits);
@@ -113,6 +109,22 @@ public class Trie {
         return collectedEmits;
     }
 
+    public void parseText(ParseConfiguration parseConfiguration) {
+        checkForConstructedFailureStates();
+
+        int position = 0;
+        State currentState = this.rootState;
+        for (Character character : parseConfiguration) {
+            if (trieConfig.isCaseInsensitive()) {
+                character = Character.toLowerCase(character);
+            }
+            currentState = getState(currentState, character);
+            storeEmits(position, currentState, parseConfiguration.getEmitHandler());
+            position++;
+        }
+
+    }
+
     private void removePartialMatches(String searchText, List<Emit> collectedEmits) {
         long size = searchText.length();
         List<Emit> removeEmits = new ArrayList<Emit>();
@@ -175,11 +187,11 @@ public class Trie {
         }
     }
 
-    private void storeEmits(int position, State currentState, List<Emit> collectedEmits) {
+    private void storeEmits(int position, State currentState, EmitHandler emitHandler) {
         Collection<String> emits = currentState.emit();
         if (emits != null && !emits.isEmpty()) {
             for (String emit : emits) {
-                collectedEmits.add(new Emit(position-emit.length()+1, position, emit));
+                emitHandler.emit(new Emit(position - emit.length() + 1, position, emit));
             }
         }
     }

src/main/java/org/ahocorasick/trie/configuration/ParseConfiguration.java

@@ -0,0 +1,43 @@
+package org.ahocorasick.trie.configuration;
+
+import org.ahocorasick.trie.handler.EmitHandler;
+
+import java.io.Reader;
+import java.util.Iterator;
+
+public class ParseConfiguration implements Iterable<Character> {
+
+    private String text;
+
+    private Reader reader;
+
+    private EmitHandler emitHandler;
+
+    public ParseConfiguration setText(String text) {
+        this.text = text;
+        return this;
+    }
+
+    public ParseConfiguration setText(Reader reader) {
+        this.reader = reader;
+        return this;
+    }
+
+    public ParseConfiguration setEmitHandler(EmitHandler emitHandler) {
+        this.emitHandler = emitHandler;
+        return this;
+    }
+
+    public EmitHandler getEmitHandler() {
+        return emitHandler;
+    }
+
+    @Override
+    public Iterator<Character> iterator() {
+        if (reader != null) {
+            return new ReaderIterator(reader);
+        }
+        return new StringIterator(text);
+    }
+
+}

src/main/java/org/ahocorasick/trie/configuration/ReaderIterator.java

@@ -0,0 +1,44 @@
+package org.ahocorasick.trie.configuration;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.Reader;
+import java.util.Iterator;
+
+public class ReaderIterator implements Iterator<Character> {
+
+    private Reader reader;
+
+    private int readCharacter;
+
+    public ReaderIterator(Reader reader) {
+        this.reader = reader;
+        readIntoBuffer();
+    }
+
+    private void readIntoBuffer() {
+        try {
+            readCharacter = reader.read();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    @Override
+    public boolean hasNext() {
+        return readCharacter != -1;
+    }
+
+    @Override
+    public Character next() {
+        Character returnChar = (char)readCharacter;
+        readIntoBuffer();
+        return returnChar;
+    }
+
+    @Override
+    public void remove() {
+        throw new UnsupportedOperationException();
+    }
+
+}

src/main/java/org/ahocorasick/trie/configuration/StringIterator.java

@@ -0,0 +1,30 @@
+package org.ahocorasick.trie.configuration;
+
+import java.util.Iterator;
+
+public class StringIterator implements Iterator<Character> {
+
+    private int counter = 0;
+
+    private String text;
+
+    public StringIterator(String text) {
+        this.text = text;
+    }
+
+    @Override
+    public boolean hasNext() {
+        return counter < text.length();
+    }
+
+    @Override
+    public Character next() {
+        return text.charAt(counter++);
+    }
+
+    @Override
+    public void remove() {
+        throw new UnsupportedOperationException();
+    }
+
+}

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

@@ -0,0 +1,21 @@
+package org.ahocorasick.trie.handler;
+
+import org.ahocorasick.trie.Emit;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class DefaultEmitHandler implements EmitHandler {
+
+    private List<Emit> emits = new ArrayList<>();
+
+    @Override
+    public void emit(Emit emit) {
+        this.emits.add(emit);
+    }
+
+    public List<Emit> getEmits() {
+        return this.emits;
+    }
+
+}

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

@@ -0,0 +1,7 @@
+package org.ahocorasick.trie.handler;
+
+import org.ahocorasick.trie.Emit;
+
+public interface EmitHandler {
+    void emit(Emit emit);
+}

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

@@ -1,9 +1,13 @@
 package org.ahocorasick.trie;
 
+import org.ahocorasick.trie.configuration.ParseConfiguration;
+import org.ahocorasick.trie.handler.EmitHandler;
 import org.junit.Test;
 
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Iterator;
+import java.util.List;
 
 import static junit.framework.Assert.assertEquals;
 
@@ -53,6 +57,30 @@ public class TrieTest {
         checkEmit(iterator.next(), 2, 5, "hers");
     }
 
+    @Test
+    public void ushersTestByCallback() {
+        Trie trie = new Trie();
+        trie.addKeyword("hers");
+        trie.addKeyword("his");
+        trie.addKeyword("she");
+        trie.addKeyword("he");
+
+        final List<Emit> emits = new ArrayList<>();
+        EmitHandler emitHandler = new EmitHandler() {
+
+            @Override
+            public void emit(Emit emit) {
+                emits.add(emit);
+            }
+        };
+        trie.parseText(new ParseConfiguration().setText("ushers").setEmitHandler(emitHandler));
+        assertEquals(3, emits.size()); // she @ 3, he @ 3, hers @ 5
+        Iterator<Emit> iterator = emits.iterator();
+        checkEmit(iterator.next(), 2, 3, "he");
+        checkEmit(iterator.next(), 1, 3, "she");
+        checkEmit(iterator.next(), 2, 5, "hers");
+    }
+
     @Test
     public void misleadingTest() {
         Trie trie = new Trie();

src/test/java/org/ahocorasick/trie/configuration/ParseConfigurationTest.java

@@ -0,0 +1,33 @@
+package org.ahocorasick.trie.configuration;
+
+import org.junit.Test;
+
+import java.io.IOException;
+import java.io.StringReader;
+
+import static org.junit.Assert.assertEquals;
+
+public class ParseConfigurationTest {
+
+    @Test
+    public void reader() throws IOException {
+        StringReader reader = new StringReader("hällö");
+        ParseConfiguration parseConfiguration = new ParseConfiguration().setText(reader);
+        assertIterator(parseConfiguration);
+        reader.close();
+    }
+
+    @Test
+    public void string() throws IOException {
+        ParseConfiguration parseConfiguration = new ParseConfiguration().setText("hällö");
+        assertIterator(parseConfiguration);
+    }
+
+    private void assertIterator(ParseConfiguration parseConfiguration) {
+        StringBuffer text = new StringBuffer();
+        for (Character character : parseConfiguration) {
+            text.append(character);
+        }
+        assertEquals("hällö", text.toString());
+    }
+}