added stopwords cleaner with tests

.gitignore

@@ -10,4 +10,7 @@ target/
 *.iml
 *.ipr
 *.iws
-/.idea/
+/.idea/
+
+.DS_Store
+

duke-core/src/main/java/no/priv/garshol/duke/cleaners/StopwordsCleaner.java

@@ -0,0 +1,63 @@
+
+package no.priv.garshol.duke.cleaners;
+
+import no.priv.garshol.duke.Cleaner;
+
+import java.io.*;
+import java.util.List;
+import java.util.ArrayList;
+
+/**
+ * A cleaner which removes english stopwords from a string.
+ */
+
+public class StopwordsCleaner implements Cleaner {
+    private LowerCaseNormalizeCleaner sub;
+    HashSet<String> stopwords = new HashSet<String>();
+    private ArrayList<String> wordsList = new ArrayList<String>();
+
+
+    public StopwordsCleaner() {
+        this.sub = new LowerCaseNormalizeCleaner();
+
+        try {
+            this.stopwords = loadStopwords();
+        } catch (DukeException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+
+    public String clean(String value) {
+
+        value = sub.clean(value);
+        if (value == null || value.equals(""))
+            return value;
+
+
+        for (String word : words) {
+          if (!stopwords.contains(word))
+            wordsList.add(word);
+        }
+
+        return String.join(" ",wordsList);
+
+    }
+
+    private HashSet<String> loadStopwords() throws IOException {
+        String mapfile = "no/priv/garshol/duke/english-stopwords.txt";
+
+        BufferedReader in = new BufferedReader(new FileReader(mapfile));
+        String str;
+
+        HashSet<String> stopwords = new HashSet<String>();
+        while((str = in.readLine()) != null){
+            stopwords.add(str);
+        }
+
+        in.close();
+        return stopwords;
+    }
+
+}
+

duke-core/src/test/java/no/priv/garshol/duke/cleaners/StopwordsCleanerTest.java

@@ -0,0 +1,32 @@
+
+package no.priv.garshol.duke.cleaners;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import static junit.framework.Assert.assertEquals;
+import static junit.framework.Assert.assertTrue;
+
+public class StopwordsCleanerTest extends LowerCaseNormalizeCleanerTest {
+
+    public void setUp() {
+        cleaner = new StopwordsCleaner();
+    }
+
+    @Test
+    public void testMapping() {
+        assertEquals("Hello my name is duke", cleaner.clean("hello name duke"));
+    }
+
+    @Test
+  	public void testEmpty() {
+    	assertTrue(cleaner.clean("") == "");
+  	}
+
+    @Test
+  	public void testNull() {
+    	assertTrue(cleaner.clean(null) == null);
+  	}
+
+
+}