Unittest that prooves saving and loading work properly

src/main/java/Credential.java

@@ -1,4 +1,6 @@
-public class Credential {
+import java.io.Serializable;
+
+public class Credential implements Serializable {
 
     private String name, password;
     private int id;

src/main/java/CredentialList.java

@@ -0,0 +1,4 @@
+import java.io.Serializable;
+import java.util.ArrayList;
+
+public class CredentialList extends ArrayList<Credential> implements Serializable{}

src/main/java/CredentialRepository.java

@@ -1,4 +1,7 @@
-import java.util.ArrayList;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
 
 /**
  * Credential Repository for handling user credentials
@@ -8,7 +11,7 @@ import java.util.ArrayList;
 public class CredentialRepository implements CredentialRepositoryInterface{
 
     private int idCounter = 0;
-    private ArrayList<Credential> credentials;
+    private CredentialList credentials;
 
     /**
      * Konstruktor
@@ -17,7 +20,7 @@ public class CredentialRepository implements CredentialRepositoryInterface{
      */
     public CredentialRepository()
     {
-        this.credentials = new ArrayList<Credential>();
+        this.credentials = new CredentialList();
     }
 
 
@@ -128,6 +131,48 @@ public class CredentialRepository implements CredentialRepositoryInterface{
 
     }
 
+    /**
+     * Function for serialization of all Credentials
+     * @param fileName
+     */
+
+    public void serializeObject(String fileName)
+    {
+        if(fileName.equals("")) return;
+
+        try {
+            FileOutputStream file = new FileOutputStream(this.getWorkingDirectory() + fileName + ".claud11");
+            ObjectOutputStream out = new ObjectOutputStream(file);
+            out.writeObject(this.credentials);
+        } catch (Exception fail) {
+            System.err.println("Serialization failed!");
+            fail.printStackTrace();
+        }
+    }
+
+    /**
+     * Function to load serialized Objects from hard drive by path
+     * @param fileName
+     */
+    public void deserializeObjects(String fileName)
+    {
+        if(fileName.equals("")) return;
+
+        try {
+            FileInputStream file = new FileInputStream(this.getWorkingDirectory() + fileName + ".claud11");
+            ObjectInputStream in = new ObjectInputStream(file);
+
+            this.credentials = (CredentialList)in.readObject();
+
+            in.close();
+            file.close();
+
+        } catch(Exception fail)
+        {
+            System.err.println("Loading of CredentialRepository failed");
+        }
+    }
+
     /**
      * helper function to check list size after insertion / deletion
      * @return
@@ -138,6 +183,16 @@ public class CredentialRepository implements CredentialRepositoryInterface{
         return this.credentials.size();
     }
 
+    /**
+     * Helper function for serialization
+      * @return
+     */
+
+    private String getWorkingDirectory()
+    {
+        return System.getProperty("user.dir");
+    }
+
 }
 
 

src/test/java/CredentialRepositoryTest.java

@@ -81,4 +81,39 @@ class CredentialRepositoryTest {
         Assertions.assertEquals(null, this.credentialRepository.getCredentialsViaId(0));
     }
 
+    @Test
+    void testSerializeObject(){
+
+        this.credentialRepository.createNewCredential("mock", "mock");
+        this.credentialRepository.serializeObject("testName");
+    }
+
+    @Test
+    void testLoadingOfSerializedObject(){
+
+        this.credentialRepository.createNewCredential("mock1", "mock1");
+        this.credentialRepository.createNewCredential("mock2", "mock2");
+        this.credentialRepository.createNewCredential("mock3", "mock3");
+
+        Credential temporary1 = this.credentialRepository.getCredentialsViaId(0);
+        Credential temporary2 = this.credentialRepository.getCredentialsViaId(1);
+        Credential temporary3 = this.credentialRepository.getCredentialsViaId(2);
+
+        this.credentialRepository.serializeObject("unitTest_Deserialization");
+
+        //delete entries to proove we really load something
+        this.credentialRepository.delete(0);
+        this.credentialRepository.delete(0);
+        Assertions.assertEquals(null, this.credentialRepository.getCredentialsViaName("mock2") );
+
+        //load and deserialize object and proove objects are back
+        this.credentialRepository.deserializeObjects("unitTest_Deserialization");
+        Assertions.assertEquals(temporary1.getName(), this.credentialRepository.getCredentialsViaName("mock1").getName());
+        Assertions.assertEquals(temporary1.getPassword(), this.credentialRepository.getCredentialsViaName("mock1").getPassword());
+        Assertions.assertEquals(temporary2.getName(), this.credentialRepository.getCredentialsViaName("mock2").getName());
+        Assertions.assertEquals(temporary2.getPassword(), this.credentialRepository.getCredentialsViaName("mock2").getPassword());
+        Assertions.assertEquals(temporary3.getName(), this.credentialRepository.getCredentialsViaName("mock3").getName());
+        Assertions.assertEquals(temporary3.getPassword(), this.credentialRepository.getCredentialsViaName("mock3").getPassword());
+    }
+
 }