Added support for logging to a file (from the Logger)

Contacts.iml

@@ -5,12 +5,24 @@
       <map />
     </option>
   </component>
+  <component name="FacetManager">
+    <facet type="jpa" name="JPA">
+      <configuration>
+        <setting name="validation-enabled" value="true" />
+        <datasource-mapping>
+          <factory-entry name="contacts-pu" />
+        </datasource-mapping>
+        <naming-strategy-map />
+        <deploymentDescriptor name="persistence.xml" url="file://$MODULE_DIR$/src/META-INF/persistence.xml" />
+      </configuration>
+    </facet>
+  </component>
   <component name="NewModuleRootManager" inherit-compiler-output="true">
     <exclude-output />
     <content url="file://$MODULE_DIR$">
       <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
     </content>
-    <orderEntry type="jdk" jdkName="1.8.0_201" jdkType="JavaSDK" />
+    <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="library" name="libs" level="project" />
   </component>

src/META-INF/persistence.xml

@@ -17,7 +17,7 @@
             <!-- Alternatives: create-tables, drop-and-create-tables-->
             <property name="eclipselink.ddl-generation" value="create-tables"/>
             <!-- Alternatives: FINE (logs all SQL), ALL, CONFIG, INFO, WARNING..., OFF -->
-            <property name="eclipselink.logging.level" value="FINE"/>
+            <property name="eclipselink.logging.level" value="OFF"/>
 
             <!--
              The Database can be pre-filled with entries during startup. This would be very useful during testing

src/no/ntnu/idata2001/contacts/model/AddressBookDBHandler.java

@@ -3,6 +3,8 @@ package no.ntnu.idata2001.contacts.model;
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.List;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 import javax.persistence.EntityManager;
 import javax.persistence.EntityManagerFactory;
 import javax.persistence.Persistence;
@@ -20,12 +22,12 @@ import javax.persistence.Query;
  * communication with the underlying RDBMS. Creating an EntityManagerFactory instance is costly:</p>
  *
  * <p>(<a href="https://docs.jboss.org/hibernate/entitymanager/3.5/reference/en/html_single/#d0e980">)
- *   "An entity manager factory is typically create at application initialization time and closed at
- *  * application end. It's creation is an expensive process."</a></p>
+ * "An entity manager factory is typically create at application initialization time and closed at
+ * * application end. It's creation is an expensive process."</a></p>
  * <p>
- *  Hence the EMF is implemented as a field in this class.
+ * Hence the EMF is implemented as a field in this class.
  * </p>
- *  <p><b>NOTE:</b> While the EMF is <b>thread safe</b>, the EM is <b>not thread safe</b>.</p>
+ * <p><b>NOTE:</b> While the EMF is <b>thread safe</b>, the EM is <b>not thread safe</b>.</p>
  */
 public class AddressBookDBHandler implements AddressBook {
 
@@ -36,6 +38,9 @@ public class AddressBookDBHandler implements AddressBook {
   // communicate with the database, and should hence not be serialized.
   private final transient EntityManagerFactory efact;
 
+  // Create a logger to be used within this class
+  private final transient Logger logger = Logger.getLogger(this.getClass().getName());
+
   /**
    * Creates an instance of the AddressBookDBHandler.
    */
@@ -50,26 +55,55 @@ public class AddressBookDBHandler implements AddressBook {
     eman.persist(contact);
     eman.getTransaction().commit();
     eman.close();
+    this.logger.log(Level.INFO, () ->
+        "A contact was added to the DB. Name = "
+            + contact.getName() + " Phone = "
+            + contact.getPhone());
   }
 
   @Override
   public void removeContact(String phoneNumber) {
-    //TODO: To be implemented later...
+    EntityManager eman = this.efact.createEntityManager();
+
+    eman.getTransaction().begin();
+
+    String sql = "DELETE FROM ContactDetails c WHERE c.phone LIKE :contactPhone";
+
+    Query query = eman.createQuery(sql).setParameter("contactPhone", phoneNumber);
+    int n = query.executeUpdate();
+
+    eman.getTransaction().commit();
+
+    // A quick note on this way of logging a message where we need to use
+    // string concatenation: String concatenation is "expensive". Hence we should
+    // avoid having to build the string if it is not going to be used, i.e. if the
+    // logging level is set to lower than INFO, this log-message will never be logged
+    // even though the string concatenation always will been performed.
+    // One solution, is to use lambda like shown below. This way we ensure that the lambda
+    // expression will not be executed unless the logging level is set to INFO or higher.
+    // Another alternative is to use a formatter.
+    this.logger.log(Level.INFO, () -> "Removed contact with phone = "
+        + phoneNumber + ". EM returned " + n + " object deleted.");
+
+    eman.close();
+
   }
 
   @Override
   public Collection<ContactDetails> getAllContacts() {
     EntityManager eman = this.efact.createEntityManager();
 
-    List<ContactDetails> contactsList = null;
-
     String sql = "SELECT c FROM ContactDetails c";
 
     Query query = eman.createQuery(sql);
-    contactsList = query.getResultList();
+
+    List<ContactDetails> contactsList = query.getResultList();
 
     eman.close();
 
+
+    this.logger.log(Level.INFO, () ->
+        "Read all contacts from the DB, a total of " + contactsList.size());
     return contactsList;
   }
 

src/no/ntnu/idata2001/contacts/views/ContactsApp.java

 package no.ntnu.idata2001.contacts.views;
 
+import java.io.IOException;
+import java.util.logging.FileHandler;
+import java.util.logging.Handler;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 import javafx.application.Application;
 import javafx.collections.FXCollections;
 import javafx.collections.ObservableList;
@@ -50,6 +55,15 @@ public class ContactsApp extends Application {
    * @param args command line arguments provided during startup. Not used in this app.
    */
   public static void main(String[] args) {
+    // Setup logging to file, and the level to FINEST
+    try {
+      Handler fh = new FileHandler("./contacts.log");
+      Logger.getLogger("no.ntnu.idata2001.contacts").addHandler(fh);
+      Logger.getLogger("no.ntnu.idata2001.contacts").setLevel(Level.FINEST);
+    } catch (IOException e) {
+      Logger.getLogger(ContactsApp.class.getName()).log(Level.SEVERE,
+          "Could not create a log-file.");
+    }
     launch(args);
   }