Merge pull request #142 from flipkart-incubator/bugFix

bug fix while removing object from queue

batching/src/main/java/com/flipkart/batching/tape/InMemoryObjectQueue.java

@@ -15,6 +15,8 @@
  */
 package com.flipkart.batching.tape;
 
+import com.flipkart.batching.toolbox.LogUtil;
+
 import java.util.ArrayList;
 import java.util.LinkedList;
 import java.util.List;
@@ -27,6 +29,7 @@
  * @param <T> The type of elements in the queue.
  */
 public class InMemoryObjectQueue<T> implements ObjectQueue<T> {
+    private static final String TAG = "InMemoryObjectQueue";
     private final Queue<T> tasks;
     private Listener<T> listener;
 
@@ -53,8 +56,10 @@ public int size() {
 
     @Override
     public void remove() {
-        tasks.remove();
-        if (listener != null) listener.onRemove(this);
+        removeFromQueue();
+        if (listener != null) {
+            listener.onRemove(this);
+        }
     }
 
     @Override
@@ -64,6 +69,15 @@ public void remove(int n) {
         }
     }
 
+    private void removeFromQueue() {
+        if (tasks.isEmpty()) {
+            LogUtil.log(TAG, "The queue is empty");
+            return;
+        }
+
+        tasks.remove();
+    }
+
     @Override
     public void close() {
         tasks.clear();

batching/src/test/java/com/flipkart/batching/tape/InMemoryObjectQueueTest.java

@@ -0,0 +1,43 @@
+package com.flipkart.batching.tape;
+
+import com.flipkart.batching.BuildConfig;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.annotation.Config;
+
+import java.util.ArrayList;
+
+/**
+ * Test for {@link InMemoryObjectQueue}
+ */
+
+@RunWith(RobolectricTestRunner.class)
+@Config(constants = BuildConfig.class, sdk = 21)
+public class InMemoryObjectQueueTest {
+
+    /**
+     * Test for {@link InMemoryObjectQueue#remove()} )
+     */
+    @Test
+    public void testRemove() {
+        InMemoryObjectQueue<String> inMemoryObjectQueue = new InMemoryObjectQueue<>();
+
+        ArrayList<String> arrayList = new ArrayList<>(4);
+        arrayList.add("test1");
+        arrayList.add("test2");
+        arrayList.add("test3");
+        arrayList.add("test4");
+
+        for (String sample : arrayList) {
+            inMemoryObjectQueue.add(sample);
+        }
+
+        //remove all the 4 elements added to the queue
+        inMemoryObjectQueue.remove(arrayList.size());
+
+        //try removing another element from the queue.
+        inMemoryObjectQueue.remove();
+    }
+}