Merge pull request #4 from jihoonson/feature/avoid_null

Avoid returning nulls when the result is not found
shineware · Dec 19, 2016 · 60fd6d6 · 60fd6d6
2 parents 74c1fab + cb6aa9a
commit 60fd6d6
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Showing 3 changed files with 99 additions and 65 deletions.
diff --git a/src/main/java/kr/co/shineware/ds/aho_corasick/AhoCorasickDictionary.java b/src/main/java/kr/co/shineware/ds/aho_corasick/AhoCorasickDictionary.java
@@ -141,7 +141,7 @@ public Map<String,V> get(FindContext<V> context, char key) {
 			if (children == null) {
 				final AhoCorasickNode<V> currentNode = context.getCurrentFailNode();
 				if (currentNode == null) {
-					return null;
+					return new HashMap<>();
 				} else {
 					context.setCurrentNode(currentNode);
 				}
@@ -171,9 +171,7 @@ public Map<String,V> get(FindContext<V> context, char key) {
 			}
 			break;
 		}
-		if(resultMap.size() == 0){
-			return null;
-		}
+
 		return resultMap;
 	}	
 
@@ -209,9 +207,6 @@ public Map<String,V> get(FindContext<V> context, char[] keys) {
 		for (int i = 0; i < keys.length; i++) {
 			resultMap.putAll(get(context, keys[i]));
 		}
-		if(resultMap.size() == 0){
-			return null;
-		}
 		return resultMap;
 	}
 

diff --git a/src/test/java/kr/co/shineware/ds/aho_corasick/AhoCorasickDictionaryConcurrencyTest.java b/src/test/java/kr/co/shineware/ds/aho_corasick/AhoCorasickDictionaryConcurrencyTest.java
@@ -0,0 +1,89 @@
+package kr.co.shineware.ds.aho_corasick;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.*;
+import java.util.concurrent.*;
+
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class AhoCorasickDictionaryConcurrencyTest {
+
+	private static ExecutorService service;
+	private static final int THREAD_NUM = 4;
+	private static final int DATA_NUM = 100000;
+
+	private static String[] KEYS;
+	private static Integer[] VALS;
+
+	private static final AhoCorasickDictionary<Integer> dic = new AhoCorasickDictionary<>();
+
+	@BeforeClass
+	public static void setup() {
+		KEYS = new String[DATA_NUM];
+		VALS = new Integer[DATA_NUM];
+
+		for (int i = 0; i < KEYS.length; i++) {
+			KEYS[i] = Integer.toString(i);
+			VALS[i] = i;
+		}
+
+		for (int i = 0; i < KEYS.length; i++) {
+			dic.put(KEYS[i], VALS[i]);
+		}
+		dic.buildFailLink();
+
+		service = Executors.newFixedThreadPool(THREAD_NUM);
+	}
+
+	@AfterClass
+	public static void teardown() {
+		if (service != null) {
+			service.shutdown();
+		}
+	}
+
+	@Test
+	public void testSequentialGet() {
+		for (int i = 0; i < KEYS.length; i++) {
+			final Map<String, Integer> result = dic.get(KEYS[i]);
+			final Set<Integer> expectedResult = expectedResultSet(KEYS[i]);
+
+			assertEquals(expectedResult, new HashSet<>(result.values()));
+		}
+	}
+
+	@Test
+	public void testConcurrentGet() throws ExecutionException, InterruptedException {
+		final List<Future> futures = new ArrayList<>();
+		for (int i = 0; i < KEYS.length; i++) {
+			final int index = i;
+			futures.add(service.submit(new Callable<Set<Integer>>() {
+				@Override
+				public Set<Integer> call() throws Exception {
+					return new HashSet<>(dic.get(KEYS[index]).values());
+				}
+			}));
+		}
+
+		for (int i = 0; i < futures.size(); i++) {
+			final Set<Integer> expectedResult = expectedResultSet(KEYS[i]);
+			assertEquals(expectedResult, futures.get(i).get());
+		}
+	}
+
+	private static Set<Integer> expectedResultSet(final String str) {
+		final Set<Integer> resultSet = new HashSet<>();
+
+		for (int subStrLen = 1; subStrLen < str.length() + 1; subStrLen++) {
+			for (int subStrBeginIdx = 0; subStrBeginIdx + subStrLen <= str.length(); subStrBeginIdx++) {
+				final String subStr = str.substring(subStrBeginIdx, subStrBeginIdx + subStrLen);
+				resultSet.add(Integer.parseInt(subStr));
+			}
+		}
+
+		return resultSet;
+	}
+}
diff --git a/src/test/java/kr/co/shineware/ds/aho_corasick/AhoCorasickDictionaryTest.java b/src/test/java/kr/co/shineware/ds/aho_corasick/AhoCorasickDictionaryTest.java
@@ -1,20 +1,16 @@
 package kr.co.shineware.ds.aho_corasick;
 
-import static org.junit.Assert.assertEquals;
-
-import java.util.*;
-import java.util.concurrent.*;
-
-import org.junit.AfterClass;
 import org.junit.BeforeClass;
 import org.junit.Test;
 
-public class AhoCorasickDictionaryTest {
+import java.util.HashMap;
+import java.util.Map;
 
-	private static ExecutorService service;
-	private static final int THREAD_NUM = 4;
-	private static final int DATA_NUM = 100000;
+import static org.junit.Assert.assertEquals;
+
+public class AhoCorasickDictionaryTest {
 
+	private static final int DATA_NUM = 100;
 	private static String[] KEYS;
 	private static Integer[] VALS;
 
@@ -34,15 +30,6 @@ public static void setup() {
 			dic.put(KEYS[i], VALS[i]);
 		}
 		dic.buildFailLink();
-
-		service = Executors.newFixedThreadPool(THREAD_NUM);
-	}
-
-	@AfterClass
-	public static void teardown() {
-		if (service != null) {
-			service.shutdown();
-		}
 	}
 
 	@Test
@@ -71,44 +58,7 @@ private static Map<String, Integer> expectedResultMapForGetWithSingleChar(final
 	}
 
 	@Test
-	public void testSequentialGet() {
-		for (int i = 0; i < KEYS.length; i++) {
-			final Map<String, Integer> result = dic.get(KEYS[i]);
-			final Set<Integer> expectedResult = expectedResultSet(KEYS[i]);
-
-			assertEquals(expectedResult, new HashSet<>(result.values()));
-		}
-	}
-
-	@Test
-	public void testConcurrentGet() throws ExecutionException, InterruptedException {
-		final List<Future> futures = new ArrayList<>();
-		for (int i = 0; i < KEYS.length; i++) {
-			final int index = i;
-			futures.add(service.submit(new Callable<Set<Integer>>() {
-				@Override
-				public Set<Integer> call() throws Exception {
-					return new HashSet<>(dic.get(KEYS[index]).values());
-				}
-			}));
-		}
-
-		for (int i = 0; i < futures.size(); i++) {
-			final Set<Integer> expectedResult = expectedResultSet(KEYS[i]);
-			assertEquals(expectedResult, futures.get(i).get());
-		}
-	}
-
-	private static Set<Integer> expectedResultSet(final String str) {
-		final Set<Integer> resultSet = new HashSet<>();
-
-		for (int subStrLen = 1; subStrLen < str.length() + 1; subStrLen++) {
-			for (int subStrBeginIdx = 0; subStrBeginIdx + subStrLen <= str.length(); subStrBeginIdx++) {
-				final String subStr = str.substring(subStrBeginIdx, subStrBeginIdx + subStrLen);
-				resultSet.add(Integer.parseInt(subStr));
-			}
-		}
-
-		return resultSet;
+	public void testNotFound() {
+		assertEquals(new HashMap<>(), dic.get(dic.newFindContext(), "가"));
 	}
 }