Issue #273: Changed DB to internal Java data structure to avoid compilation errors + decrease in code coverage

caching/etc/caching.ucls

@@ -57,7 +57,7 @@
   </class>  
   <class id="7" language="java" name="main.java.com.wssia.caching.UserAccount" project="CachingPatterns" 
     file="/CachingPatterns/src/main/java/com/wssia/caching/UserAccount.java" binary="false" corner="BOTTOM_RIGHT">    
-    <position height="-1" width="-1" x="1137" y="382"/>    
+    <position height="-1" width="-1" x="1140" y="405"/>    
     <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
       sort-features="false" accessors="true" visibility="true">      
       <attributes public="true" package="true" protected="true" private="true" static="true"/>      

caching/pom.xml

@@ -33,8 +33,8 @@
   <!--
     Due to the use of MongoDB in the test of this pattern, TRAVIS and/or MAVEN might fail if the DB connection is
     not open for the JUnit test. To avoid disrupting the compilation process, the surefire plug-in was used
-    to SKIP the running of the JUnit tests for this pattern. To RE-ACTIVATE the running of the tests, change the
+    to SKIP the running of the JUnit tests for this pattern. To ACTIVATE the running of the tests, change the
-    skipTests (below) flag to 'false'.
+    skipTests (below) flag to 'false' and vice-versa.
   -->
   <build>
     <plugins>
@@ -43,7 +43,7 @@
         <artifactId>maven-surefire-plugin</artifactId>
         <version>2.19</version>
         <configuration>
-          <skipTests>true</skipTests>
+          <skipTests>false</skipTests>
         </configuration>
       </plugin>
     </plugins>

caching/src/main/java/com/wssia/caching/AppManager.java

@@ -15,11 +15,21 @@ public class AppManager {
 
   private static CachingPolicy cachingPolicy;
 
-  public static void init() {
+  /**
-    try {
+   *
-      DBManager.connect();
+   * Developer/Tester is able to choose whether the application should use MongoDB as its underlying
-    } catch (ParseException e) {
+   * data storage or a simple Java data structure to (temporarily) store the data/objects during
-      e.printStackTrace();
+   * runtime.
+   */
+  public static void initDB(boolean useMongoDB) {
+    if (useMongoDB) {
+      try {
+        DBManager.connect();
+      } catch (ParseException e) {
+        e.printStackTrace();
+      }
+    } else {
+      DBManager.createVirtualDB();
     }
   }
 

caching/src/main/java/com/wssia/caching/CacheStore.java

@@ -42,7 +42,7 @@ public class CacheStore {
     if (cache.contains(userAccount.getUserID())) {
       DBManager.updateDB(userAccount);
       cache.invalidate(userAccount.getUserID()); // Cache data has been updated -- remove older
-      // version from cache.
+                                                 // version from cache.
     } else {
       DBManager.writeToDB(userAccount);
     }

caching/src/main/java/com/wssia/caching/DBManager.java

@@ -1,6 +1,7 @@
 package main.java.com.wssia.caching;
 
 import java.text.ParseException;
+import java.util.HashMap;
 
 import org.bson.Document;
 
@@ -15,18 +16,35 @@ import com.mongodb.client.model.UpdateOptions;
  * implemented methods for querying, inserting, and updating data. MongoDB was used as the database
  * for the application.
  *
+ * Developer/Tester is able to choose whether the application should use MongoDB as its underlying
+ * data storage (connect()) or a simple Java data structure to (temporarily) store the data/objects
+ * during runtime (createVirtualDB()).
  */
 public class DBManager {
 
   private static MongoClient mongoClient;
   private static MongoDatabase db;
+  private static boolean useMongoDB;
+
+  private static HashMap<String, UserAccount> virtualDB;
+
+  public static void createVirtualDB() {
+    useMongoDB = false;
+    virtualDB = new HashMap<String, UserAccount>();
+  }
 
   public static void connect() throws ParseException {
+    useMongoDB = true;
     mongoClient = new MongoClient();
     db = mongoClient.getDatabase("test");
   }
 
   public static UserAccount readFromDB(String userID) {
+    if (!useMongoDB) {
+      if (virtualDB.containsKey(userID))
+        return virtualDB.get(userID);
+      return null;
+    }
     if (null == db) {
       try {
         connect();
@@ -45,6 +63,10 @@ public class DBManager {
   }
 
   public static void writeToDB(UserAccount userAccount) {
+    if (!useMongoDB) {
+      virtualDB.put(userAccount.getUserID(), userAccount);
+      return;
+    }
     if (null == db) {
       try {
         connect();
@@ -58,6 +80,10 @@ public class DBManager {
   }
 
   public static void updateDB(UserAccount userAccount) {
+    if (!useMongoDB) {
+      virtualDB.put(userAccount.getUserID(), userAccount);
+      return;
+    }
     if (null == db) {
       try {
         connect();
@@ -76,6 +102,10 @@ public class DBManager {
    * Insert data into DB if it does not exist. Else, update it.
    */
   public static void upsertDB(UserAccount userAccount) {
+    if (!useMongoDB) {
+      virtualDB.put(userAccount.getUserID(), userAccount);
+      return;
+    }
     if (null == db) {
       try {
         connect();

caching/src/main/java/com/wssia/caching/LRUCache.java

@@ -138,7 +138,7 @@ public class LRUCache {
   public void setCapacity(int newCapacity) {
     if (capacity > newCapacity) {
       clear(); // Behavior can be modified to accommodate for decrease in cache size. For now, we'll
-      // just clear the cache.
+               // just clear the cache.
     } else {
       this.capacity = newCapacity;
     }

caching/src/test/java/com/wssia/caching/AppTest.java

@@ -19,7 +19,10 @@ public class AppTest {
    */
   @Before
   public void setUp() {
-    AppManager.init();
+    AppManager.initDB(false); // VirtualDB (instead of MongoDB) was used in running the JUnit tests
+                              // to avoid Maven compilation errors. Set flag to true to run the
+                              // tests with MongoDB (provided that MongoDB is installed and socket
+                              // connection is open).
     AppManager.initCacheCapacity(3);
     app = new App();
   }