Merge pull request #146 from informatik-ag-ngl/f/single_file_local_db

Store user specific local database information inside a single file

src/main/java/envoy/client/data/PersistentLocalDB.java

@@ -1,12 +1,12 @@
 package envoy.client.data;
 
-import java.io.File;
-import java.io.IOException;
+import java.io.*;
 import java.util.ArrayList;
 import java.util.HashMap;
 
-import envoy.data.ConfigItem;
 import envoy.data.IDGenerator;
+import envoy.data.Message;
+import envoy.event.MessageStatusChangeEvent;
 import envoy.util.SerializationUtils;
 
 /**
@@ -21,92 +21,67 @@ import envoy.util.SerializationUtils;
  * @author Maximilian Käfer
  * @since Envoy Client v0.1-alpha
  */
-public class PersistentLocalDB extends LocalDB {
+public final class PersistentLocalDB extends LocalDB {
 
-	private File localDBDir, localDBFile, usersFile, idGeneratorFile, messageCacheFile, statusCacheFile;
+	private File dbDir, userFile, idGeneratorFile, usersFile;
 
 	/**
-	 * Initializes an empty local database without a directory. All changes made to
-	 * this instance cannot be saved to the file system.<br>
-	 * <br>
-	 * This constructor shall be used in conjunction with the {@code ignoreLocalDB}
-	 * {@link ConfigItem}.
+	 * Constructs an empty local database. To serialize any user-specific data to
+	 * the file system, call {@link PersistentLocalDB#initializeUserStorage()} first
+	 * and then {@link PersistentLocalDB#save()}.
 	 *
-	 * @since Envoy Client v0.3-alpha
-	 */
-	public PersistentLocalDB() {}
-
-	/**
-	 * Constructs an empty local database. To serialize any chats to the file
-	 * system, call {@link PersistentLocalDB#initializeUserStorage()}.
-	 *
-	 * @param localDBDir the directory in which to store users and chats
-	 * @throws IOException if the PersistentLocalDB could not be initialized
+	 * @param dbDir the directory in which to persist data
+	 * @throws IOException if {@code dbDir} is a file (and not a directory)
 	 * @since Envoy Client v0.1-alpha
 	 */
-	public PersistentLocalDB(File localDBDir) throws IOException {
-		this.localDBDir = localDBDir;
+	public PersistentLocalDB(File dbDir) throws IOException {
+		this.dbDir = dbDir;
 
-		// Initialize local database directory
-		if (localDBDir.exists() && !localDBDir.isDirectory())
-			throw new IOException(String.format("LocalDBDir '%s' is not a directory!", localDBDir.getAbsolutePath()));
-		usersFile		= new File(localDBDir, "users.db");
-		idGeneratorFile	= new File(localDBDir, "id_generator.db");
+		// Test if the database directory is actually a directory
+		if (dbDir.exists() && !dbDir.isDirectory())
+			throw new IOException(String.format("LocalDBDir '%s' is not a directory!", dbDir.getAbsolutePath()));
+
+		// Initialize global files
+		idGeneratorFile	= new File(dbDir, "id_gen.db");
+		usersFile		= new File(dbDir, "users.db");
 	}
 
 	/**
-	 * Creates a database file for a user-specific list of chats.<br>
-	 * {@inheritDoc}
+	 * Creates a database file for a user-specific list of chats.
 	 *
-	 * @throws NullPointerException if the client user is not yet specified
+	 * @throws IllegalStateException if the client user is not specified
 	 * @since Envoy Client v0.1-alpha
 	 */
 	@Override
 	public void initializeUserStorage() {
-		if (user == null) throw new NullPointerException("Client user is null");
-		localDBFile			= new File(localDBDir, user.getID() + ".db");
-		messageCacheFile	= new File(localDBDir, user.getID() + "_message_cache.db");
-		statusCacheFile		= new File(localDBDir, user.getID() + "_status_cache.db");
+		if (user == null) throw new IllegalStateException("Client user is null, cannot initialize user storage");
+		userFile = new File(dbDir, user.getID() + ".db");
 	}
 
-	/**
-	 * {@inheritDoc}
-	 */
 	@Override
 	public void save() throws IOException {
 		// Save users
 		SerializationUtils.write(usersFile, users);
 
 		// Save user data
-		if (user != null) {
-			SerializationUtils.write(localDBFile, chats);
-			SerializationUtils.write(messageCacheFile, messageCache);
-			SerializationUtils.write(statusCacheFile, statusCache);
-		}
+		if (user != null) SerializationUtils.write(userFile, chats, messageCache, statusCache);
 
 		// Save id generator
 		if (hasIDGenerator()) SerializationUtils.write(idGeneratorFile, idGenerator);
 	}
 
-	/**
-	 * {@inheritDoc}
-	 */
 	@Override
 	public void loadUsers() throws ClassNotFoundException, IOException { users = SerializationUtils.read(usersFile, HashMap.class); }
 
-	/**
-	 * {@inheritDoc}
-	 */
 	@Override
 	public void loadUserData() throws ClassNotFoundException, IOException {
-		chats			= SerializationUtils.read(localDBFile, ArrayList.class);
-		messageCache	= SerializationUtils.read(messageCacheFile, Cache.class);
-		statusCache		= SerializationUtils.read(statusCacheFile, Cache.class);
+		try (var in = new ObjectInputStream(new FileInputStream(userFile))) {
+			chats = (ArrayList<Chat>) in.readObject();
+			messageCache	= (Cache<Message>) in.readObject();
+			statusCache		= (Cache<MessageStatusChangeEvent>) in.readObject();
+		}
 	}
 
-	/**
-	 * {@inheritDoc}
-	 */
 	@Override
 	public void loadIDGenerator() {
 		try {

src/main/java/envoy/client/data/TransientLocalDB.java

@@ -11,5 +11,5 @@ package envoy.client.data;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.3-alpha
  */
-public class TransientLocalDB extends LocalDB {
+public final class TransientLocalDB extends LocalDB {
 }