Replaced private messages with private groups.

Private messages are now the same as group messages, but groups can be private or public. When a contact is added, a private group is created and designated as the inbox for exchanging private messages with the contact.
2026-02-15 20:29:52 +01:00 · 2013-12-19 21:53:26 +00:00
parent 1d4213e9c6
commit 0dc869228b
61 changed files with 1717 additions and 2329 deletions
--- a/briar-android/src/net/sf/briar/android/DescendingHeaderComparator.java
+++ b/briar-android/src/net/sf/briar/android/DescendingHeaderComparator.java
@@ -1,19 +0,0 @@
-package net.sf.briar.android;
-
-import java.util.Comparator;
-
-import net.sf.briar.api.db.MessageHeader;
-
-public class DescendingHeaderComparator implements Comparator<MessageHeader> {
-
-	public static final DescendingHeaderComparator INSTANCE =
-			new DescendingHeaderComparator();
-
-	public int compare(MessageHeader a, MessageHeader b) {
-		// The newest message comes first
-		long aTime = a.getTimestamp(), bTime = b.getTimestamp();
-		if(aTime > bTime) return -1;
-		if(aTime < bTime) return 1;
-		return 0;
-	}
-}
--- a/briar-android/src/net/sf/briar/android/SetupActivity.java
+++ b/briar-android/src/net/sf/briar/android/SetupActivity.java
@@ -12,7 +12,6 @@ import static android.widget.LinearLayout.VERTICAL;
 import static net.sf.briar.android.util.CommonLayoutParams.MATCH_MATCH;
 import static net.sf.briar.android.util.CommonLayoutParams.WRAP_WRAP;

-import java.io.IOException;
 import java.util.Arrays;
 import java.util.concurrent.Executor;

@@ -188,13 +187,8 @@ public class SetupActivity extends RoboActivity implements OnClickListener {
 				KeyPair keyPair = crypto.generateSignatureKeyPair();
 				final byte[] publicKey = keyPair.getPublic().getEncoded();
 				final byte[] privateKey = keyPair.getPrivate().getEncoded();
-				LocalAuthor a;
-				try {
-					a = authorFactory.createLocalAuthor(nickname, publicKey,
-							privateKey);
-				} catch(IOException e) {
-					throw new RuntimeException(e);
-				}
+				LocalAuthor a = authorFactory.createLocalAuthor(nickname,
+						publicKey, privateKey);
 				showHomeScreen(referenceManager.putReference(a,
 						LocalAuthor.class));				
 			}
--- a/briar-android/src/net/sf/briar/android/contact/ContactListActivity.java
+++ b/briar-android/src/net/sf/briar/android/contact/ContactListActivity.java
@@ -24,7 +24,6 @@ import java.util.logging.Logger;
 import javax.inject.Inject;

 import net.sf.briar.R;
-import net.sf.briar.android.groups.NoContactsDialog;
 import net.sf.briar.android.invitation.AddContactActivity;
 import net.sf.briar.android.util.HorizontalBorder;
 import net.sf.briar.android.util.HorizontalSpace;
@@ -34,32 +33,29 @@ import net.sf.briar.api.ContactId;
 import net.sf.briar.api.android.DatabaseUiExecutor;
 import net.sf.briar.api.db.DatabaseComponent;
 import net.sf.briar.api.db.DbException;
+import net.sf.briar.api.db.MessageHeader;
 import net.sf.briar.api.db.NoSuchContactException;
-import net.sf.briar.api.db.PrivateMessageHeader;
 import net.sf.briar.api.db.event.ContactAddedEvent;
 import net.sf.briar.api.db.event.ContactRemovedEvent;
 import net.sf.briar.api.db.event.DatabaseEvent;
 import net.sf.briar.api.db.event.DatabaseListener;
+import net.sf.briar.api.db.event.MessageAddedEvent;
 import net.sf.briar.api.db.event.MessageExpiredEvent;
-import net.sf.briar.api.db.event.PrivateMessageAddedEvent;
 import net.sf.briar.api.lifecycle.LifecycleManager;
 import net.sf.briar.api.transport.ConnectionListener;
 import net.sf.briar.api.transport.ConnectionRegistry;
-import roboguice.activity.RoboFragmentActivity;
+import roboguice.activity.RoboActivity;
 import android.content.Intent;
 import android.net.Uri;
 import android.os.Bundle;
-import android.support.v4.app.Fragment;
-import android.support.v4.app.FragmentManager;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.widget.ImageButton;
 import android.widget.LinearLayout;
 import android.widget.ListView;

-public class ContactListActivity extends RoboFragmentActivity
-implements OnClickListener, DatabaseListener, ConnectionListener,
-NoContactsDialog.Listener {
+public class ContactListActivity extends RoboActivity
+implements OnClickListener, DatabaseListener, ConnectionListener {

 	private static final Logger LOG =
 			Logger.getLogger(ContactListActivity.class.getName());
@@ -68,9 +64,7 @@ NoContactsDialog.Listener {
 	private ContactListAdapter adapter = null;
 	private ListView list = null;
 	private ListLoadingProgressBar loading = null;
-	private ImageButton addContactButton = null, composeButton = null;
-	private ImageButton shareButton = null;
-	private NoContactsDialog noContactsDialog = null;
+	private ImageButton addContactButton = null, shareButton = null;

 	// Fields that are accessed from background threads must be volatile
 	@Inject private volatile DatabaseComponent db;
@@ -113,13 +107,6 @@ NoContactsDialog.Listener {
 		footer.addView(addContactButton);
 		footer.addView(new HorizontalSpace(this));

-		composeButton = new ImageButton(this);
-		composeButton.setBackgroundResource(0);
-		composeButton.setImageResource(R.drawable.content_new_email);
-		composeButton.setOnClickListener(this);
-		footer.addView(composeButton);
-		footer.addView(new HorizontalSpace(this));
-
 		shareButton = new ImageButton(this);
 		shareButton.setBackgroundResource(0);
 		shareButton.setImageResource(R.drawable.social_share);
@@ -129,12 +116,6 @@ NoContactsDialog.Listener {
 		layout.addView(footer);

 		setContentView(layout);
-
-		FragmentManager fm = getSupportFragmentManager();
-		Fragment f = fm.findFragmentByTag("NoContactsDialog");
-		if(f == null) noContactsDialog = new NoContactsDialog();
-		else noContactsDialog = (NoContactsDialog) f;
-		noContactsDialog.setListener(this);
 	}

 	@Override
@@ -142,11 +123,11 @@ NoContactsDialog.Listener {
 		super.onResume();
 		db.addListener(this);
 		connectionRegistry.addListener(this);
-		loadHeaders();
+		loadContacts();
 	}

-	private void loadHeaders() {
-		clearHeaders();
+	private void loadContacts() {
+		clearContacts();
 		dbUiExecutor.execute(new Runnable() {
 			public void run() {
 				try {
@@ -157,9 +138,9 @@ NoContactsDialog.Listener {
 						Long lastConnected = times.get(c.getId());
 						if(lastConnected == null) continue;
 						try {
-							Collection<PrivateMessageHeader> headers =
-									db.getPrivateMessageHeaders(c.getId());
-							displayHeaders(c, lastConnected, headers);
+							Collection<MessageHeader> headers =
+									db.getInboxMessageHeaders(c.getId());
+							displayContact(c, lastConnected, headers);
 						} catch(NoSuchContactException e) {
 							if(LOG.isLoggable(INFO))
 								LOG.info("Contact removed");
@@ -181,7 +162,7 @@ NoContactsDialog.Listener {
 		});
 	}

-	private void clearHeaders() {
+	private void clearContacts() {
 		runOnUiThread(new Runnable() {
 			public void run() {
 				list.setVisibility(GONE);
@@ -192,8 +173,8 @@ NoContactsDialog.Listener {
 		});
 	}

-	private void displayHeaders(final Contact c, final long lastConnected,
-			final Collection<PrivateMessageHeader> headers) {
+	private void displayContact(final Contact c, final long lastConnected,
+			final Collection<MessageHeader> headers) {
 		runOnUiThread(new Runnable() {
 			public void run() {
 				list.setVisibility(VISIBLE);
@@ -239,14 +220,6 @@ NoContactsDialog.Listener {
 	public void onClick(View view) {
 		if(view == addContactButton) {
 			startActivity(new Intent(this, AddContactActivity.class));
-		} else if(view == composeButton) {
-			if(adapter.isEmpty()) {
-				FragmentManager fm = getSupportFragmentManager();
-				noContactsDialog.show(fm, "NoContactsDialog");
-			} else {
-				startActivity(new Intent(this,
-						WritePrivateMessageActivity.class));
-			}
 		} else if(view == shareButton) {
 			String apkPath = getPackageCodePath();
 			Intent i = new Intent(ACTION_SEND);
@@ -259,28 +232,28 @@ NoContactsDialog.Listener {

 	public void eventOccurred(DatabaseEvent e) {
 		if(e instanceof ContactAddedEvent) {
-			loadHeaders();
+			loadContacts();
 		} else if(e instanceof ContactRemovedEvent) {
 			// Reload the conversation, expecting NoSuchContactException
 			if(LOG.isLoggable(INFO)) LOG.info("Contact removed, reloading");
-			reloadHeaders(((ContactRemovedEvent) e).getContactId());
+			reloadContact(((ContactRemovedEvent) e).getContactId());
+		} else if(e instanceof MessageAddedEvent) {
+			if(LOG.isLoggable(INFO)) LOG.info("Message added, reloading");
+			reloadContact(((MessageAddedEvent) e).getContactId());
 		} else if(e instanceof MessageExpiredEvent) {
 			if(LOG.isLoggable(INFO)) LOG.info("Message expired, reloading");
-			loadHeaders();
-		} else if(e instanceof PrivateMessageAddedEvent) {
-			if(LOG.isLoggable(INFO)) LOG.info("Message added, reloading");
-			reloadHeaders(((PrivateMessageAddedEvent) e).getContactId());
+			loadContacts();
 		}
 	}

-	private void reloadHeaders(final ContactId c) {
+	private void reloadContact(final ContactId c) {
 		dbUiExecutor.execute(new Runnable() {
 			public void run() {
 				try {
 					lifecycleManager.waitForDatabase();
 					long now = System.currentTimeMillis();
-					Collection<PrivateMessageHeader> headers =
-							db.getPrivateMessageHeaders(c);
+					Collection<MessageHeader> headers =
+							db.getInboxMessageHeaders(c);
 					long duration = System.currentTimeMillis() - now;
 					if(LOG.isLoggable(INFO))
 						LOG.info("Partial load took " + duration + " ms");
@@ -301,18 +274,11 @@ NoContactsDialog.Listener {
 	}

 	private void updateItem(final ContactId c,
-			final Collection<PrivateMessageHeader> headers) {
+			final Collection<MessageHeader> headers) {
 		runOnUiThread(new Runnable() {
 			public void run() {
 				ContactListItem item = findItem(c);
-				if(item == null) return;
-				// Replace the item with a new item containing the new headers
-				adapter.remove(item);
-				item = new ContactListItem(item.getContact(),
-						item.isConnected(), item.getLastConnected(), headers);
-				adapter.add(item);
-				adapter.sort(ItemComparator.INSTANCE);
-				adapter.notifyDataSetChanged();
+				if(item != null) item.setHeaders(headers);
 			}
 		});
 	}
@@ -337,28 +303,16 @@ NoContactsDialog.Listener {
 	private void setConnected(final ContactId c, final boolean connected) {
 		runOnUiThread(new Runnable() {
 			public void run() {
-				int count = adapter.getCount();
-				for(int i = 0; i < count; i++) {
-					ContactListItem item = adapter.getItem(i);
-					if(item.getContactId().equals(c)) {
-						if(LOG.isLoggable(INFO))
-							LOG.info("Updating connection time");
-						item.setConnected(connected);
-						item.setLastConnected(System.currentTimeMillis());
-						list.invalidateViews();
-						return;
-					}
-				}
+				ContactListItem item = findItem(c);
+				if(item == null) return;
+				if(LOG.isLoggable(INFO)) LOG.info("Updating connection time");
+				item.setConnected(connected);
+				item.setLastConnected(System.currentTimeMillis());
+				list.invalidateViews();
 			}
 		});
 	}

-	public void contactCreationSelected() {
-		startActivity(new Intent(this, AddContactActivity.class));
-	}
-
-	public void contactCreationCancelled() {}
-
 	private static class ItemComparator implements Comparator<ContactListItem> {

 		private static final ItemComparator INSTANCE = new ItemComparator();
--- a/briar-android/src/net/sf/briar/android/contact/ContactListItem.java
+++ b/briar-android/src/net/sf/briar/android/contact/ContactListItem.java
@@ -1,15 +1,11 @@
 package net.sf.briar.android.contact;

-import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
-import java.util.List;

-import net.sf.briar.android.DescendingHeaderComparator;
 import net.sf.briar.api.AuthorId;
 import net.sf.briar.api.Contact;
 import net.sf.briar.api.ContactId;
-import net.sf.briar.api.db.PrivateMessageHeader;
+import net.sf.briar.api.db.MessageHeader;

 // This class is not thread-safe
 class ContactListItem {
@@ -17,27 +13,27 @@ class ContactListItem {
 	private final Contact contact;
 	private boolean connected;
 	private long lastConnected;
-	private final boolean empty;
-	private final long timestamp;
-	private final int unread;
+	private boolean empty;
+	private long timestamp;
+	private int unread;

 	ContactListItem(Contact contact, boolean connected, long lastConnected,
-			Collection<PrivateMessageHeader> headers) {
+			Collection<MessageHeader> headers) {
 		this.contact = contact;
 		this.connected = connected;
 		this.lastConnected = lastConnected;
+		setHeaders(headers);
+	}
+
+	void setHeaders(Collection<MessageHeader> headers) {
 		empty = headers.isEmpty();
-		if(empty) {
-			timestamp = 0;
-			unread = 0;
-		} else {
-			List<PrivateMessageHeader> list =
-					new ArrayList<PrivateMessageHeader>(headers);
-			Collections.sort(list, DescendingHeaderComparator.INSTANCE);
-			timestamp = list.get(0).getTimestamp();
-			int unread = 0;
-			for(PrivateMessageHeader h : list) if(!h.isRead()) unread++;
-			this.unread = unread;
+		timestamp = 0;
+		unread = 0;
+		if(!empty) {
+			for(MessageHeader h : headers) {
+				if(h.getTimestamp() > timestamp) timestamp = h.getTimestamp();
+				if(!h.isRead()) unread++;
+			}
 		}
 	}

--- a/briar-android/src/net/sf/briar/android/contact/ContactSpinnerAdapter.java
+++ b/briar-android/src/net/sf/briar/android/contact/ContactSpinnerAdapter.java
@@ -1,77 +0,0 @@
-package net.sf.briar.android.contact;
-
-import static net.sf.briar.android.contact.ContactItem.NEW;
-
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.List;
-
-import net.sf.briar.R;
-import android.content.Context;
-import android.content.res.Resources;
-import android.view.View;
-import android.view.ViewGroup;
-import android.widget.BaseAdapter;
-import android.widget.SpinnerAdapter;
-import android.widget.TextView;
-
-public class ContactSpinnerAdapter extends BaseAdapter
-implements SpinnerAdapter {
-
-	private final Context ctx;
-	private final List<ContactItem> list = new ArrayList<ContactItem>();
-
-	public ContactSpinnerAdapter(Context ctx) {
-		this.ctx = ctx;
-	}
-
-	public void add(ContactItem item) {
-		list.add(item);
-	}
-
-	public void clear() {
-		list.clear();
-	}
-
-	public int getCount() {
-		return list.isEmpty() ? 0 : list.size() + 1;
-	}
-
-	@Override
-	public View getDropDownView(int position, View convertView,
-			ViewGroup parent) {
-		return getView(position, convertView, parent);
-	}
-
-	public ContactItem getItem(int position) {
-		if(position == list.size()) return NEW;
-		return list.get(position);
-	}
-
-	public long getItemId(int position) {
-		return android.R.layout.simple_spinner_item;
-	}
-
-	public View getView(int position, View convertView, ViewGroup parent) {
-		TextView name = new TextView(ctx);
-		name.setTextSize(18);
-		name.setMaxLines(1);
-		Resources res = ctx.getResources();
-		int pad = res.getInteger(R.integer.spinner_padding);
-		name.setPadding(pad, pad, pad, pad);
-		ContactItem item = getItem(position);
-		if(item == NEW) name.setText(R.string.new_contact_item);
-		else name.setText(item.getContact().getAuthor().getName());
-		return name;
-	}
-
-	@Override
-	public boolean isEmpty() {
-		return list.isEmpty();
-	}
-
-	public void sort(Comparator<ContactItem> comparator) {
-		Collections.sort(list, comparator);
-	}
-}
--- a/briar-android/src/net/sf/briar/android/contact/ConversationActivity.java
+++ b/briar-android/src/net/sf/briar/android/contact/ConversationActivity.java
@@ -16,22 +16,21 @@ import java.util.logging.Logger;
 import javax.inject.Inject;

 import net.sf.briar.R;
-import net.sf.briar.android.AscendingHeaderComparator;
 import net.sf.briar.android.util.HorizontalBorder;
 import net.sf.briar.android.util.ListLoadingProgressBar;
-import net.sf.briar.api.AuthorId;
 import net.sf.briar.api.ContactId;
 import net.sf.briar.api.android.DatabaseUiExecutor;
 import net.sf.briar.api.db.DatabaseComponent;
 import net.sf.briar.api.db.DbException;
+import net.sf.briar.api.db.MessageHeader;
 import net.sf.briar.api.db.NoSuchContactException;
-import net.sf.briar.api.db.PrivateMessageHeader;
 import net.sf.briar.api.db.event.ContactRemovedEvent;
 import net.sf.briar.api.db.event.DatabaseEvent;
 import net.sf.briar.api.db.event.DatabaseListener;
+import net.sf.briar.api.db.event.MessageAddedEvent;
 import net.sf.briar.api.db.event.MessageExpiredEvent;
-import net.sf.briar.api.db.event.PrivateMessageAddedEvent;
 import net.sf.briar.api.lifecycle.LifecycleManager;
+import net.sf.briar.api.messaging.GroupId;
 import roboguice.activity.RoboActivity;
 import android.content.Intent;
 import android.os.Bundle;
@@ -53,13 +52,14 @@ implements DatabaseListener, OnClickListener, OnItemClickListener {
 	private ConversationAdapter adapter = null;
 	private ListView list = null;
 	private ListLoadingProgressBar loading = null;
+	private ImageButton composeButton = null;

 	// Fields that are accessed from background threads must be volatile
 	@Inject private volatile DatabaseComponent db;
 	@Inject @DatabaseUiExecutor private volatile Executor dbUiExecutor;
 	@Inject private volatile LifecycleManager lifecycleManager;
 	private volatile ContactId contactId = null;
-	private volatile AuthorId localAuthorId = null;
+	private volatile GroupId groupId = null;

 	@Override
 	public void onCreate(Bundle state) {
@@ -72,9 +72,6 @@ implements DatabaseListener, OnClickListener, OnItemClickListener {
 		contactName = i.getStringExtra("net.sf.briar.CONTACT_NAME");
 		if(contactName == null) throw new IllegalStateException();
 		setTitle(contactName);
-		byte[] b = i.getByteArrayExtra("net.sf.briar.LOCAL_AUTHOR_ID");
-		if(b == null) throw new IllegalStateException();
-		localAuthorId = new AuthorId(b);

 		LinearLayout layout = new LinearLayout(this);
 		layout.setLayoutParams(MATCH_MATCH);
@@ -96,9 +93,10 @@ implements DatabaseListener, OnClickListener, OnItemClickListener {

 		layout.addView(new HorizontalBorder(this));

-		ImageButton composeButton = new ImageButton(this);
+		composeButton = new ImageButton(this);
 		composeButton.setBackgroundResource(0);
 		composeButton.setImageResource(R.drawable.content_new_email);
+		composeButton.setEnabled(false); // Enabled after loading the headers
 		composeButton.setOnClickListener(this);
 		layout.addView(composeButton);

@@ -118,8 +116,9 @@ implements DatabaseListener, OnClickListener, OnItemClickListener {
 				try {
 					lifecycleManager.waitForDatabase();
 					long now = System.currentTimeMillis();
-					Collection<PrivateMessageHeader> headers =
-							db.getPrivateMessageHeaders(contactId);
+					groupId = db.getInboxGroup(contactId);
+					Collection<MessageHeader> headers =
+							db.getInboxMessageHeaders(contactId);
 					long duration = System.currentTimeMillis() - now;
 					if(LOG.isLoggable(INFO))
 						LOG.info("Load took " + duration + " ms");
@@ -143,15 +142,16 @@ implements DatabaseListener, OnClickListener, OnItemClickListener {
 		});
 	}

-	private void displayHeaders(
-			final Collection<PrivateMessageHeader> headers) {
+	private void displayHeaders(final Collection<MessageHeader> headers) {
 		runOnUiThread(new Runnable() {
 			public void run() {
 				list.setVisibility(VISIBLE);
 				loading.setVisibility(GONE);
+				composeButton.setEnabled(true);
 				adapter.clear();
-				for(PrivateMessageHeader h : headers) adapter.add(h);
-				adapter.sort(AscendingHeaderComparator.INSTANCE);
+				for(MessageHeader h : headers)
+					adapter.add(new ConversationItem(h));
+				adapter.sort(ConversationItemComparator.INSTANCE);
 				adapter.notifyDataSetChanged();
 				selectFirstUnread();
 			}
@@ -161,7 +161,7 @@ implements DatabaseListener, OnClickListener, OnItemClickListener {
 	private void selectFirstUnread() {
 		int firstUnread = -1, count = adapter.getCount();
 		for(int i = 0; i < count; i++) {
-			if(!adapter.getItem(i).isRead()) {
+			if(!adapter.getItem(i).getHeader().isRead()) {
 				firstUnread = i;
 				break;
 			}
@@ -200,22 +200,21 @@ implements DatabaseListener, OnClickListener, OnItemClickListener {
 					}
 				});
 			}
-		} else if(e instanceof MessageExpiredEvent) {
-			if(LOG.isLoggable(INFO)) LOG.info("Message expired, reloading");
-			loadHeaders();
-		} else if(e instanceof PrivateMessageAddedEvent) {
-			PrivateMessageAddedEvent p = (PrivateMessageAddedEvent) e;
-			if(p.getContactId().equals(contactId)) {
+		} else if(e instanceof MessageAddedEvent) {
+			if(((MessageAddedEvent) e).getContactId().equals(contactId)) {
 				if(LOG.isLoggable(INFO)) LOG.info("Message added, reloading");
 				loadHeaders();
 			}
+		} else if(e instanceof MessageExpiredEvent) {
+			if(LOG.isLoggable(INFO)) LOG.info("Message expired, reloading");
+			loadHeaders();
 		}
 	}

 	public void onClick(View view) {
 		Intent i = new Intent(this, WritePrivateMessageActivity.class);
 		i.putExtra("net.sf.briar.CONTACT_ID", contactId.getInt());
-		i.putExtra("net.sf.briar.LOCAL_AUTHOR_ID", localAuthorId.getBytes());
+		i.putExtra("net.sf.briar.GROUP_ID", groupId.getBytes());
 		startActivity(i);
 	}

@@ -225,14 +224,15 @@ implements DatabaseListener, OnClickListener, OnItemClickListener {
 	}

 	private void displayMessage(int position) {
-		PrivateMessageHeader item = adapter.getItem(position);
+		MessageHeader header = adapter.getItem(position).getHeader();
 		Intent i = new Intent(this, ReadPrivateMessageActivity.class);
 		i.putExtra("net.sf.briar.CONTACT_ID", contactId.getInt());
 		i.putExtra("net.sf.briar.CONTACT_NAME", contactName);
-		i.putExtra("net.sf.briar.AUTHOR_NAME", item.getAuthor().getName());
-		i.putExtra("net.sf.briar.MESSAGE_ID", item.getId().getBytes());
-		i.putExtra("net.sf.briar.CONTENT_TYPE", item.getContentType());
-		i.putExtra("net.sf.briar.TIMESTAMP", item.getTimestamp());
+		i.putExtra("net.sf.briar.GROUP_ID", header.getGroupId().getBytes());
+		i.putExtra("net.sf.briar.AUTHOR_NAME", header.getAuthor().getName());
+		i.putExtra("net.sf.briar.MESSAGE_ID", header.getId().getBytes());
+		i.putExtra("net.sf.briar.CONTENT_TYPE", header.getContentType());
+		i.putExtra("net.sf.briar.TIMESTAMP", header.getTimestamp());
 		startActivityForResult(i, position);
 	}
 }
--- a/briar-android/src/net/sf/briar/android/contact/ConversationAdapter.java
+++ b/briar-android/src/net/sf/briar/android/contact/ConversationAdapter.java
@@ -7,7 +7,7 @@ import static net.sf.briar.android.util.CommonLayoutParams.WRAP_WRAP_1;
 import java.util.ArrayList;

 import net.sf.briar.R;
-import net.sf.briar.api.db.PrivateMessageHeader;
+import net.sf.briar.api.db.MessageHeader;
 import android.content.Context;
 import android.content.res.Resources;
 import android.text.format.DateUtils;
@@ -17,21 +17,21 @@ import android.widget.ArrayAdapter;
 import android.widget.LinearLayout;
 import android.widget.TextView;

-class ConversationAdapter extends ArrayAdapter<PrivateMessageHeader> {
+class ConversationAdapter extends ArrayAdapter<ConversationItem> {

 	ConversationAdapter(Context ctx) {
 		super(ctx, android.R.layout.simple_expandable_list_item_1,
-				new ArrayList<PrivateMessageHeader>());
+				new ArrayList<ConversationItem>());
 	}

 	@Override
 	public View getView(int position, View convertView, ViewGroup parent) {
-		PrivateMessageHeader item = getItem(position);
+		MessageHeader header = getItem(position).getHeader();
 		Context ctx = getContext();

 		LinearLayout layout = new LinearLayout(ctx);
 		layout.setOrientation(HORIZONTAL);
-		if(!item.isRead()) {
+		if(!header.isRead()) {
 			Resources res = ctx.getResources();
 			layout.setBackgroundColor(res.getColor(R.color.unread_background));
 		}
@@ -42,13 +42,13 @@ class ConversationAdapter extends ArrayAdapter<PrivateMessageHeader> {
 		name.setTextSize(18);
 		name.setMaxLines(1);
 		name.setPadding(10, 10, 10, 10);
-		name.setText(item.getAuthor().getName());
+		name.setText(header.getAuthor().getName());
 		layout.addView(name);

 		TextView date = new TextView(ctx);
 		date.setTextSize(14);
 		date.setPadding(0, 10, 10, 10);
-		long then = item.getTimestamp(), now = System.currentTimeMillis();
+		long then = header.getTimestamp(), now = System.currentTimeMillis();
 		date.setText(DateUtils.formatSameDayTime(then, now, SHORT, SHORT));
 		layout.addView(date);

--- a/briar-android/src/net/sf/briar/android/contact/ConversationItem.java
+++ b/briar-android/src/net/sf/briar/android/contact/ConversationItem.java
@@ -0,0 +1,37 @@
+package net.sf.briar.android.contact;
+
+import net.sf.briar.api.db.MessageHeader;
+
+// This class is not thread-safe
+class ConversationItem {
+
+	private final MessageHeader header;
+	private boolean expanded;
+	private byte[] body;
+
+	ConversationItem(MessageHeader header) {
+		this.header = header;
+		expanded = false;
+		body = null;
+	}
+
+	MessageHeader getHeader() {
+		return header;
+	}
+
+	boolean isExpanded() {
+		return expanded;
+	}
+
+	void setExpanded(boolean expanded) {
+		this.expanded = expanded;
+	}
+
+	byte[] getBody() {
+		return body;
+	}
+
+	void setBody(byte[] body) {
+		this.body = body;
+	}
+}
--- a/briar-android/src/net/sf/briar/android/contact/ConversationItemComparator.java
+++ b/briar-android/src/net/sf/briar/android/contact/ConversationItemComparator.java
@@ -0,0 +1,19 @@
+package net.sf.briar.android.contact;
+
+import java.util.Comparator;
+
+public class ConversationItemComparator
+implements Comparator<ConversationItem> {
+
+	public static final ConversationItemComparator INSTANCE =
+			new ConversationItemComparator();
+
+	public int compare(ConversationItem a, ConversationItem b) {
+		// The oldest message comes first
+		long aTime = a.getHeader().getTimestamp();
+		long bTime = b.getHeader().getTimestamp();
+		if(aTime < bTime) return -1;
+		if(aTime > bTime) return 1;
+		return 0;
+	}
+}
--- a/briar-android/src/net/sf/briar/android/contact/ReadPrivateMessageActivity.java
+++ b/briar-android/src/net/sf/briar/android/contact/ReadPrivateMessageActivity.java
@@ -26,6 +26,7 @@ import net.sf.briar.api.db.DatabaseComponent;
 import net.sf.briar.api.db.DbException;
 import net.sf.briar.api.db.NoSuchMessageException;
 import net.sf.briar.api.lifecycle.LifecycleManager;
+import net.sf.briar.api.messaging.GroupId;
 import net.sf.briar.api.messaging.MessageId;
 import roboguice.activity.RoboActivity;
 import android.content.Intent;
@@ -60,6 +61,7 @@ implements OnClickListener {
 	@Inject @DatabaseUiExecutor private volatile Executor dbUiExecutor;
 	@Inject private volatile LifecycleManager lifecycleManager;
 	private volatile MessageId messageId = null;
+	private volatile GroupId groupId = null;
 	private volatile long timestamp = -1;

 	@Override
@@ -78,6 +80,9 @@ implements OnClickListener {
 		byte[] b = i.getByteArrayExtra("net.sf.briar.MESSAGE_ID");
 		if(b == null) throw new IllegalStateException();
 		messageId = new MessageId(b);
+		b = i.getByteArrayExtra("net.sf.briar.GROUP_ID");
+		if(b == null) throw new IllegalStateException();
+		groupId = new GroupId(b);
 		String contentType = i.getStringExtra("net.sf.briar.CONTENT_TYPE");
 		if(contentType == null) throw new IllegalStateException();
 		timestamp = i.getLongExtra("net.sf.briar.TIMESTAMP", -1);
@@ -262,6 +267,7 @@ implements OnClickListener {
 		} else if(view == replyButton) {
 			Intent i = new Intent(this, WritePrivateMessageActivity.class);
 			i.putExtra("net.sf.briar.CONTACT_ID", contactId.getInt());
+			i.putExtra("net.sf.briar.GROUP_ID", groupId.getBytes());
 			i.putExtra("net.sf.briar.PARENT_ID", messageId.getBytes());
 			i.putExtra("net.sf.briar.TIMESTAMP", timestamp);
 			startActivity(i);
--- a/briar-android/src/net/sf/briar/android/contact/WritePrivateMessageActivity.java
+++ b/briar-android/src/net/sf/briar/android/contact/WritePrivateMessageActivity.java
@@ -12,49 +12,46 @@ import static net.sf.briar.android.util.CommonLayoutParams.MATCH_WRAP;
 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.security.GeneralSecurityException;
-import java.util.Collection;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;

 import javax.inject.Inject;

 import net.sf.briar.R;
-import net.sf.briar.android.invitation.AddContactActivity;
 import net.sf.briar.android.util.HorizontalSpace;
-import net.sf.briar.api.AuthorId;
 import net.sf.briar.api.Contact;
 import net.sf.briar.api.ContactId;
 import net.sf.briar.api.LocalAuthor;
 import net.sf.briar.api.android.DatabaseUiExecutor;
 import net.sf.briar.api.db.DatabaseComponent;
 import net.sf.briar.api.db.DbException;
+import net.sf.briar.api.db.NoSuchContactException;
+import net.sf.briar.api.db.NoSuchSubscriptionException;
 import net.sf.briar.api.lifecycle.LifecycleManager;
+import net.sf.briar.api.messaging.Group;
+import net.sf.briar.api.messaging.GroupId;
 import net.sf.briar.api.messaging.Message;
 import net.sf.briar.api.messaging.MessageFactory;
 import net.sf.briar.api.messaging.MessageId;
 import roboguice.activity.RoboActivity;
 import android.content.Intent;
+import android.content.res.Resources;
 import android.os.Bundle;
 import android.text.InputType;
 import android.view.View;
 import android.view.View.OnClickListener;
-import android.widget.AdapterView;
-import android.widget.AdapterView.OnItemSelectedListener;
 import android.widget.EditText;
 import android.widget.ImageButton;
 import android.widget.LinearLayout;
-import android.widget.Spinner;
 import android.widget.TextView;

 public class WritePrivateMessageActivity extends RoboActivity
-implements OnItemSelectedListener, OnClickListener {
+implements OnClickListener {

 	private static final Logger LOG =
 			Logger.getLogger(WritePrivateMessageActivity.class.getName());

-	private TextView from = null;
-	private ContactSpinnerAdapter adapter = null;
-	private Spinner spinner = null;
+	private TextView from = null, to = null;
 	private ImageButton sendButton = null;
 	private EditText content = null;

@@ -63,10 +60,13 @@ implements OnItemSelectedListener, OnClickListener {
 	@Inject @DatabaseUiExecutor private volatile Executor dbUiExecutor;
 	@Inject private volatile LifecycleManager lifecycleManager;
 	@Inject private volatile MessageFactory messageFactory;
-	private volatile LocalAuthor localAuthor = null;
 	private volatile ContactId contactId = null;
+	private volatile GroupId groupId = null;
 	private volatile MessageId parentId = null;
 	private volatile long timestamp = -1;
+	private volatile Contact contact = null;
+	private volatile LocalAuthor localAuthor = null;
+	private volatile Group group = null;

 	@Override
 	public void onCreate(Bundle state) {
@@ -74,16 +74,15 @@ implements OnItemSelectedListener, OnClickListener {

 		Intent i = getIntent();
 		int id = i.getIntExtra("net.sf.briar.CONTACT_ID", -1);
-		if(id != -1) contactId = new ContactId(id);
-		byte[] b = i.getByteArrayExtra("net.sf.briar.PARENT_ID");
+		if(id == -1) throw new IllegalStateException();
+		contactId = new ContactId(id);
+		byte[] b = i.getByteArrayExtra("net.sf.briar.GROUP_ID");
+		if(b == null) throw new IllegalStateException();
+		groupId = new GroupId(b);
+		b = i.getByteArrayExtra("net.sf.briar.PARENT_ID");
 		if(b != null) parentId = new MessageId(b);
 		timestamp = i.getLongExtra("net.sf.briar.TIMESTAMP", -1);

-		if(state != null) {
-			id = state.getInt("net.sf.briar.CONTACT_ID", -1);
-			if(id != -1) contactId = new ContactId(id);
-		}
-
 		LinearLayout layout = new LinearLayout(this);
 		layout.setLayoutParams(MATCH_WRAP);
 		layout.setOrientation(VERTICAL);
@@ -104,28 +103,16 @@ implements OnItemSelectedListener, OnClickListener {
 		sendButton = new ImageButton(this);
 		sendButton.setBackgroundResource(0);
 		sendButton.setImageResource(R.drawable.social_send_now);
-		sendButton.setEnabled(false); // Enabled after loading the local author
+		sendButton.setEnabled(false); // Enabled after loading the group
 		sendButton.setOnClickListener(this);
 		header.addView(sendButton);
 		layout.addView(header);

-		header = new LinearLayout(this);
-		header.setLayoutParams(MATCH_WRAP);
-		header.setOrientation(HORIZONTAL);
-		header.setGravity(CENTER_VERTICAL);
-
-		TextView to = new TextView(this);
+		to = new TextView(this);
 		to.setTextSize(18);
-		to.setPadding(10, 0, 0, 10);
+		to.setPadding(10, 10, 10, 10);
 		to.setText(R.string.to);
-		header.addView(to);
-
-		adapter = new ContactSpinnerAdapter(this);
-		spinner = new Spinner(this);
-		spinner.setAdapter(adapter);
-		spinner.setOnItemSelectedListener(this);
-		header.addView(spinner);
-		layout.addView(header);
+		layout.addView(to);

 		content = new EditText(this);
 		content.setId(1);
@@ -140,20 +127,26 @@ implements OnItemSelectedListener, OnClickListener {
 	@Override
 	public void onResume() {
 		super.onResume();
-		loadContacts();
+		loadAuthorsAndGroup();
 	}

-	private void loadContacts() {
+	private void loadAuthorsAndGroup() {
 		dbUiExecutor.execute(new Runnable() {
 			public void run() {
 				try {
 					lifecycleManager.waitForDatabase();
 					long now = System.currentTimeMillis();
-					Collection<Contact> contacts = db.getContacts();
+					contact = db.getContact(contactId);
+					localAuthor = db.getLocalAuthor(contact.getLocalAuthorId());
+					group = db.getGroup(groupId);
 					long duration = System.currentTimeMillis() - now;
 					if(LOG.isLoggable(INFO))
-						LOG.info("Loading contacts took " + duration + " ms");
-					displayContacts(contacts);
+						LOG.info("Load took " + duration + " ms");
+					displayAuthors();
+				} catch(NoSuchContactException e) {
+					finish();
+				} catch(NoSuchSubscriptionException e) {
+					finish();
 				} catch(DbException e) {
 					if(LOG.isLoggable(WARNING))
 						LOG.log(WARNING, e.toString(), e);
@@ -165,101 +158,33 @@ implements OnItemSelectedListener, OnClickListener {
 		});
 	}

-	private void displayContacts(final Collection<Contact> contacts) {
+	private void displayAuthors() {
 		runOnUiThread(new Runnable() {
 			public void run() {
-				if(contacts.isEmpty()) finish();
-				adapter.clear();
-				for(Contact c : contacts) adapter.add(new ContactItem(c));
-				adapter.sort(ContactItemComparator.INSTANCE);
-				adapter.notifyDataSetChanged();
-				int count = adapter.getCount();
-				for(int i = 0; i < count; i++) {
-					ContactItem item = adapter.getItem(i);
-					if(item == ContactItem.NEW) continue;
-					if(item.getContact().getId().equals(contactId)) {
-						spinner.setSelection(i);
-						break;
-					}
-				}
-			}
-		});
-	}
-
-	@Override
-	public void onSaveInstanceState(Bundle state) {
-		super.onSaveInstanceState(state);
-		if(contactId != null)
-			state.putInt("net.sf.briar.CONTACT_ID", contactId.getInt());
-	}
-
-	public void onItemSelected(AdapterView<?> parent, View view, int position,
-			long id) {
-		ContactItem item = adapter.getItem(position);
-		if(item == ContactItem.NEW) {
-			contactId = null;
-			localAuthor = null;
-			startActivity(new Intent(this, AddContactActivity.class));
-		} else {
-			Contact c = item.getContact();
-			contactId = c.getId();
-			localAuthor = null;
-			loadLocalAuthor(c.getLocalAuthorId());
-		}
-		sendButton.setEnabled(false);
-	}
-
-	private void loadLocalAuthor(final AuthorId a) {
-		dbUiExecutor.execute(new Runnable() {
-			public void run() {
-				try {
-					lifecycleManager.waitForDatabase();
-					long now = System.currentTimeMillis();
-					localAuthor = db.getLocalAuthor(a);
-					long duration = System.currentTimeMillis() - now;
-					if(LOG.isLoggable(INFO))
-						LOG.info("Loading author took " + duration + " ms");
-					displayLocalAuthor();
-				} catch(DbException e) {
-					if(LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
-				} catch(InterruptedException e) {
-					LOG.info("Interrupted while waiting for database");
-					Thread.currentThread().interrupt();
-				}
-			}
-		});
-	}
-
-	private void displayLocalAuthor() {
-		runOnUiThread(new Runnable() {
-			public void run() {
-				String format = getResources().getString(R.string.format_from);
-				from.setText(String.format(format, localAuthor.getName()));
+				Resources res = getResources();
+				String format = res.getString(R.string.format_from);
+				String name = localAuthor.getName();
+				from.setText(String.format(format, name));
+				format = res.getString(R.string.format_to);
+				name = contact.getAuthor().getName();
+				to.setText(String.format(format, name));
 				sendButton.setEnabled(true);
 			}
 		});
 	}

-	public void onNothingSelected(AdapterView<?> parent) {
-		contactId = null;
-		sendButton.setEnabled(false);
-	}
-
 	public void onClick(View view) {
-		if(localAuthor == null || contactId == null)
+		if(contact == null || localAuthor == null)
 			throw new IllegalStateException();
 		try {
-			byte[] b = content.getText().toString().getBytes("UTF-8");
-			storeMessage(localAuthor, contactId, b);
+			storeMessage(content.getText().toString().getBytes("UTF-8"));
 		} catch(UnsupportedEncodingException e) {
 			throw new RuntimeException(e);
 		}
 		finish();
 	}

-	private void storeMessage(final LocalAuthor localAuthor,
-			final ContactId contactId, final byte[] body) {
+	private void storeMessage(final byte[] body) {
 		dbUiExecutor.execute(new Runnable() {
 			public void run() {
 				try {
@@ -267,10 +192,10 @@ implements OnItemSelectedListener, OnClickListener {
 					// Don't use an earlier timestamp than the parent
 					long time = System.currentTimeMillis();
 					time = Math.max(time, timestamp + 1);
-					Message m = messageFactory.createPrivateMessage(parentId,
-							"text/plain", time, body);
+					Message m = messageFactory.createAnonymousMessage(parentId,
+							group, "text/plain", time, body);
 					long now = System.currentTimeMillis();
-					db.addLocalPrivateMessage(m, contactId);
+					db.addLocalMessage(m);
 					long duration = System.currentTimeMillis() - now;
 					if(LOG.isLoggable(INFO))
 						LOG.info("Storing message took " + duration + " ms");
--- a/briar-android/src/net/sf/briar/android/groups/ConfigureGroupActivity.java
+++ b/briar-android/src/net/sf/briar/android/groups/ConfigureGroupActivity.java
@@ -77,7 +77,7 @@ SelectContactsDialog.Listener {
 		setTitle(name);
 		b = i.getByteArrayExtra("net.sf.briar.GROUP_SALT");
 		if(b == null) throw new IllegalStateException();
-		group = new Group(id, name, b);
+		group = new Group(id, name, b, false);
 		subscribed = i.getBooleanExtra("net.sf.briar.SUBSCRIBED", false);
 		boolean all = i.getBooleanExtra("net.sf.briar.VISIBLE_TO_ALL", false);

@@ -207,11 +207,11 @@ SelectContactsDialog.Listener {
 					lifecycleManager.waitForDatabase();
 					long now = System.currentTimeMillis();
 					if(subscribe) {
-						if(!wasSubscribed) db.subscribe(group);
+						if(!wasSubscribed) db.addGroup(group);
 						db.setVisibleToAll(group.getId(), all);
 						if(!all) db.setVisibility(group.getId(), visible);
 					} else if(wasSubscribed) {
-						db.unsubscribe(group);
+						db.removeGroup(group);
 					}
 					long duration = System.currentTimeMillis() - now;
 					if(LOG.isLoggable(INFO))
--- a/briar-android/src/net/sf/briar/android/groups/CreateGroupActivity.java
+++ b/briar-android/src/net/sf/briar/android/groups/CreateGroupActivity.java
@@ -13,7 +13,6 @@ import static java.util.logging.Level.WARNING;
 import static net.sf.briar.android.util.CommonLayoutParams.MATCH_MATCH;
 import static net.sf.briar.android.util.CommonLayoutParams.WRAP_WRAP;

-import java.io.IOException;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.concurrent.Executor;
@@ -174,9 +173,9 @@ SelectContactsDialog.Listener {
 				public void run() {
 					try {
 						lifecycleManager.waitForDatabase();
-						Group g = groupFactory.createGroup(name);
+						Group g = groupFactory.createGroup(name, false);
 						long now = System.currentTimeMillis();
-						db.subscribe(g);
+						db.addGroup(g);
 						if(all) db.setVisibleToAll(g.getId(), true);
 						else db.setVisibility(g.getId(), visible);
 						long duration = System.currentTimeMillis() - now;
@@ -189,8 +188,6 @@ SelectContactsDialog.Listener {
 						if(LOG.isLoggable(INFO))
 							LOG.info("Interrupted while waiting for database");
 						Thread.currentThread().interrupt();
-					} catch(IOException e) {
-						throw new RuntimeException(e);
 					}
 					runOnUiThread(new Runnable() {
 						public void run() {
--- a/briar-android/src/net/sf/briar/android/groups/GroupActivity.java
+++ b/briar-android/src/net/sf/briar/android/groups/GroupActivity.java
@@ -25,11 +25,11 @@ import net.sf.briar.api.Author;
 import net.sf.briar.api.android.DatabaseUiExecutor;
 import net.sf.briar.api.db.DatabaseComponent;
 import net.sf.briar.api.db.DbException;
-import net.sf.briar.api.db.GroupMessageHeader;
+import net.sf.briar.api.db.MessageHeader;
 import net.sf.briar.api.db.NoSuchSubscriptionException;
 import net.sf.briar.api.db.event.DatabaseEvent;
 import net.sf.briar.api.db.event.DatabaseListener;
-import net.sf.briar.api.db.event.GroupMessageAddedEvent;
+import net.sf.briar.api.db.event.MessageAddedEvent;
 import net.sf.briar.api.db.event.MessageExpiredEvent;
 import net.sf.briar.api.db.event.SubscriptionRemovedEvent;
 import net.sf.briar.api.lifecycle.LifecycleManager;
@@ -116,8 +116,8 @@ OnClickListener, OnItemClickListener {
 				try {
 					lifecycleManager.waitForDatabase();
 					long now = System.currentTimeMillis();
-					Collection<GroupMessageHeader> headers =
-							db.getGroupMessageHeaders(groupId);
+					Collection<MessageHeader> headers =
+							db.getMessageHeaders(groupId);
 					long duration = System.currentTimeMillis() - now;
 					if(LOG.isLoggable(INFO))
 						LOG.info("Load took " + duration + " ms");
@@ -141,13 +141,13 @@ OnClickListener, OnItemClickListener {
 		});
 	}

-	private void displayHeaders(final Collection<GroupMessageHeader> headers) {
+	private void displayHeaders(final Collection<MessageHeader> headers) {
 		runOnUiThread(new Runnable() {
 			public void run() {
 				list.setVisibility(VISIBLE);
 				loading.setVisibility(GONE);
 				adapter.clear();
-				for(GroupMessageHeader h : headers) adapter.add(h);
+				for(MessageHeader h : headers) adapter.add(h);
 				adapter.sort(AscendingHeaderComparator.INSTANCE);
 				adapter.notifyDataSetChanged();
 				selectFirstUnread();
@@ -187,9 +187,8 @@ OnClickListener, OnItemClickListener {
 	}

 	public void eventOccurred(DatabaseEvent e) {
-		if(e instanceof GroupMessageAddedEvent) {
-			GroupMessageAddedEvent g = (GroupMessageAddedEvent) e;
-			if(g.getGroup().getId().equals(groupId)) {
+		if(e instanceof MessageAddedEvent) {
+			if(((MessageAddedEvent) e).getGroup().getId().equals(groupId)) {
 				if(LOG.isLoggable(INFO)) LOG.info("Message added, reloading");
 				loadHeaders();
 			}
@@ -221,7 +220,7 @@ OnClickListener, OnItemClickListener {
 	}

 	private void displayMessage(int position) {
-		GroupMessageHeader item = adapter.getItem(position);
+		MessageHeader item = adapter.getItem(position);
 		Intent i = new Intent(this, ReadGroupPostActivity.class);
 		i.putExtra("net.sf.briar.GROUP_ID", groupId.getBytes());
 		i.putExtra("net.sf.briar.GROUP_NAME", groupName);
--- a/briar-android/src/net/sf/briar/android/groups/GroupAdapter.java
+++ b/briar-android/src/net/sf/briar/android/groups/GroupAdapter.java
@@ -8,7 +8,7 @@ import java.util.ArrayList;

 import net.sf.briar.R;
 import net.sf.briar.api.Author;
-import net.sf.briar.api.db.GroupMessageHeader;
+import net.sf.briar.api.db.MessageHeader;
 import android.content.Context;
 import android.content.res.Resources;
 import android.text.format.DateUtils;
@@ -18,16 +18,16 @@ import android.widget.ArrayAdapter;
 import android.widget.LinearLayout;
 import android.widget.TextView;

-class GroupAdapter extends ArrayAdapter<GroupMessageHeader> {
+class GroupAdapter extends ArrayAdapter<MessageHeader> {

 	GroupAdapter(Context ctx) {
 		super(ctx, android.R.layout.simple_expandable_list_item_1,
-				new ArrayList<GroupMessageHeader>());
+				new ArrayList<MessageHeader>());
 	}

 	@Override
 	public View getView(int position, View convertView, ViewGroup parent) {
-		GroupMessageHeader item = getItem(position);
+		MessageHeader item = getItem(position);
 		Context ctx = getContext();
 		Resources res = ctx.getResources();

--- a/briar-android/src/net/sf/briar/android/groups/GroupListActivity.java
+++ b/briar-android/src/net/sf/briar/android/groups/GroupListActivity.java
@@ -27,11 +27,11 @@ import net.sf.briar.android.util.ListLoadingProgressBar;
 import net.sf.briar.api.android.DatabaseUiExecutor;
 import net.sf.briar.api.db.DatabaseComponent;
 import net.sf.briar.api.db.DbException;
-import net.sf.briar.api.db.GroupMessageHeader;
+import net.sf.briar.api.db.MessageHeader;
 import net.sf.briar.api.db.NoSuchSubscriptionException;
 import net.sf.briar.api.db.event.DatabaseEvent;
 import net.sf.briar.api.db.event.DatabaseListener;
-import net.sf.briar.api.db.event.GroupMessageAddedEvent;
+import net.sf.briar.api.db.event.MessageAddedEvent;
 import net.sf.briar.api.db.event.MessageExpiredEvent;
 import net.sf.briar.api.db.event.RemoteSubscriptionsUpdatedEvent;
 import net.sf.briar.api.db.event.SubscriptionAddedEvent;
@@ -140,10 +140,11 @@ OnItemClickListener {
 					long now = System.currentTimeMillis();
 					for(GroupStatus s : db.getAvailableGroups()) {
 						Group g = s.getGroup();
+						if(g.isPrivate()) continue;
 						if(s.isSubscribed()) {
 							try {
-								Collection<GroupMessageHeader> headers =
-										db.getGroupMessageHeaders(g.getId());
+								Collection<MessageHeader> headers =
+										db.getMessageHeaders(g.getId());
 								displayHeaders(g, headers);
 							} catch(NoSuchSubscriptionException e) {
 								if(LOG.isLoggable(INFO))
@@ -181,7 +182,7 @@ OnItemClickListener {
 	}

 	private void displayHeaders(final Group g,
-			final Collection<GroupMessageHeader> headers) {
+			final Collection<MessageHeader> headers) {
 		runOnUiThread(new Runnable() {
 			public void run() {
 				list.setVisibility(VISIBLE);
@@ -240,9 +241,12 @@ OnItemClickListener {
 	}

 	public void eventOccurred(DatabaseEvent e) {
-		if(e instanceof GroupMessageAddedEvent) {
-			if(LOG.isLoggable(INFO)) LOG.info("Message added, reloading");
-			loadHeaders(((GroupMessageAddedEvent) e).getGroup());
+		if(e instanceof MessageAddedEvent) {
+			Group g = ((MessageAddedEvent) e).getGroup();
+			if(!g.isPrivate()) {
+				if(LOG.isLoggable(INFO)) LOG.info("Message added, reloading");
+				loadHeaders(g);
+			}
 		} else if(e instanceof MessageExpiredEvent) {
 			if(LOG.isLoggable(INFO)) LOG.info("Message expired, reloading");
 			loadHeaders();
@@ -254,9 +258,12 @@ OnItemClickListener {
 			if(LOG.isLoggable(INFO)) LOG.info("Group added, reloading");
 			loadHeaders();
 		} else if(e instanceof SubscriptionRemovedEvent) {
-			// Reload the group, expecting NoSuchSubscriptionException
-			if(LOG.isLoggable(INFO)) LOG.info("Group removed, reloading");
-			loadHeaders(((SubscriptionRemovedEvent) e).getGroup());
+			Group g = ((SubscriptionRemovedEvent) e).getGroup();
+			if(!g.isPrivate()) {
+				// Reload the group, expecting NoSuchSubscriptionException
+				if(LOG.isLoggable(INFO)) LOG.info("Group removed, reloading");
+				loadHeaders(g);
+			}
 		}
 	}

@@ -266,8 +273,8 @@ OnItemClickListener {
 				try {
 					lifecycleManager.waitForDatabase();
 					long now = System.currentTimeMillis();
-					Collection<GroupMessageHeader> headers =
-							db.getGroupMessageHeaders(g.getId());
+					Collection<MessageHeader> headers =
+							db.getMessageHeaders(g.getId());
 					long duration = System.currentTimeMillis() - now;
 					if(LOG.isLoggable(INFO))
 						LOG.info("Partial load took " + duration + " ms");
@@ -307,8 +314,10 @@ OnItemClickListener {
 					lifecycleManager.waitForDatabase();
 					int available = 0;
 					long now = System.currentTimeMillis();
-					for(GroupStatus s : db.getAvailableGroups())
-						if(!s.isSubscribed()) available++;
+					for(GroupStatus s : db.getAvailableGroups()) {
+						if(!s.isSubscribed() && !s.getGroup().isPrivate())
+							available++;
+					}
 					long duration = System.currentTimeMillis() - now;
 					if(LOG.isLoggable(INFO))
 						LOG.info("Loading available took " + duration + " ms");
@@ -354,9 +363,9 @@ OnItemClickListener {
 			startActivity(new Intent(this, ManageGroupsActivity.class));
 		} else {
 			Intent i = new Intent(this, GroupActivity.class);
-			i.putExtra("net.sf.briar.GROUP_ID",
-					item.getGroup().getId().getBytes());
-			i.putExtra("net.sf.briar.GROUP_NAME", item.getGroup().getName());
+			Group g = item.getGroup();
+			i.putExtra("net.sf.briar.GROUP_ID", g.getId().getBytes());
+			i.putExtra("net.sf.briar.GROUP_NAME", g.getName());
 			startActivity(i);
 		}
 	}
--- a/briar-android/src/net/sf/briar/android/groups/GroupListItem.java
+++ b/briar-android/src/net/sf/briar/android/groups/GroupListItem.java
@@ -1,19 +1,16 @@
 package net.sf.briar.android.groups;

-import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
-import java.util.List;

-import net.sf.briar.android.DescendingHeaderComparator;
 import net.sf.briar.api.Author;
-import net.sf.briar.api.db.GroupMessageHeader;
+import net.sf.briar.api.db.MessageHeader;
 import net.sf.briar.api.messaging.Group;

 class GroupListItem {

 	static final GroupListItem MANAGE = new GroupListItem(null,
-			Collections.<GroupMessageHeader>emptyList());
+			Collections.<MessageHeader>emptyList());

 	private final Group group;
 	private final boolean empty;
@@ -21,7 +18,7 @@ class GroupListItem {
 	private final long timestamp;
 	private final int unread;

-	GroupListItem(Group group, Collection<GroupMessageHeader> headers) {
+	GroupListItem(Group group, Collection<MessageHeader> headers) {
 		this.group = group;
 		empty = headers.isEmpty();
 		if(empty) {
@@ -30,17 +27,21 @@ class GroupListItem {
 			timestamp = 0;
 			unread = 0;
 		} else {
-			List<GroupMessageHeader> list =
-					new ArrayList<GroupMessageHeader>(headers);
-			Collections.sort(list, DescendingHeaderComparator.INSTANCE);
-			GroupMessageHeader newest = list.get(0);
+			MessageHeader newest = null;
+			long timestamp = 0;
+			int unread = 0;
+			for(MessageHeader h : headers) {
+				if(h.getTimestamp() > timestamp) {
+					timestamp = h.getTimestamp();
+					newest = h;
+				}
+				if(!h.isRead()) unread++;
+			}
 			Author a = newest.getAuthor();
 			if(a == null) authorName = null;
 			else authorName = a.getName();
 			contentType = newest.getContentType();
-			timestamp = newest.getTimestamp();
-			int unread = 0;
-			for(GroupMessageHeader h : list) if(!h.isRead()) unread++;
+			this.timestamp = newest.getTimestamp();
 			this.unread = unread;
 		}
 	}
--- a/briar-android/src/net/sf/briar/android/groups/ManageGroupsActivity.java
+++ b/briar-android/src/net/sf/briar/android/groups/ManageGroupsActivity.java
@@ -5,6 +5,7 @@ import static java.util.logging.Level.WARNING;
 import static net.sf.briar.android.groups.ManageGroupsItem.NONE;
 import static net.sf.briar.android.util.CommonLayoutParams.MATCH_MATCH;

+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Comparator;
 import java.util.concurrent.Executor;
@@ -66,20 +67,23 @@ implements DatabaseListener, OnItemClickListener {
 	public void onResume() {
 		super.onResume();
 		db.addListener(this);
-		loadAvailableGroups();
+		loadGroups();
 	}

-	private void loadAvailableGroups() {
+	private void loadGroups() {
 		dbUiExecutor.execute(new Runnable() {
 			public void run() {
 				try {
 					lifecycleManager.waitForDatabase();
 					long now = System.currentTimeMillis();
-					Collection<GroupStatus> available = db.getAvailableGroups();
+					Collection<GroupStatus> available =
+							new ArrayList<GroupStatus>();
+					for(GroupStatus s : db.getAvailableGroups())
+						if(!s.getGroup().isPrivate()) available.add(s);
 					long duration = System.currentTimeMillis() - now;
 					if(LOG.isLoggable(INFO))
 						LOG.info("Load took " + duration + " ms");
-					displayAvailableGroups(available);
+					displayGroups(available);
 				} catch(DbException e) {
 					if(LOG.isLoggable(WARNING))
 						LOG.log(WARNING, e.toString(), e);
@@ -92,14 +96,13 @@ implements DatabaseListener, OnItemClickListener {
 		});
 	}

-	private void displayAvailableGroups(
-			final Collection<GroupStatus> available) {
+	private void displayGroups(final Collection<GroupStatus> available) {
 		runOnUiThread(new Runnable() {
 			public void run() {
 				setContentView(list);
 				adapter.clear();
-				for(GroupStatus g : available)
-					adapter.add(new ManageGroupsItem(g));
+				for(GroupStatus s : available)
+					adapter.add(new ManageGroupsItem(s));
 				adapter.sort(ItemComparator.INSTANCE);
 				adapter.notifyDataSetChanged();
 			}
@@ -116,13 +119,13 @@ implements DatabaseListener, OnItemClickListener {
 		if(e instanceof RemoteSubscriptionsUpdatedEvent) {
 			if(LOG.isLoggable(INFO))
 				LOG.info("Remote subscriptions changed, reloading");
-			loadAvailableGroups();
+			loadGroups();
 		} else if(e instanceof SubscriptionAddedEvent) {
 			if(LOG.isLoggable(INFO)) LOG.info("Group added, reloading");
-			loadAvailableGroups();
+			loadGroups();
 		} else if(e instanceof SubscriptionRemovedEvent) {
 			if(LOG.isLoggable(INFO)) LOG.info("Group removed, reloading");
-			loadAvailableGroups();
+			loadGroups();
 		}
 	}

--- a/briar-android/src/net/sf/briar/android/groups/WriteGroupPostActivity.java
+++ b/briar-android/src/net/sf/briar/android/groups/WriteGroupPostActivity.java
@@ -11,6 +11,7 @@ import static net.sf.briar.android.util.CommonLayoutParams.MATCH_WRAP;

 import java.io.IOException;
 import java.security.GeneralSecurityException;
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;
@@ -71,10 +72,10 @@ implements OnItemSelectedListener, OnClickListener {
 	@Inject private volatile DatabaseComponent db;
 	@Inject @DatabaseUiExecutor private volatile Executor dbUiExecutor;
 	@Inject private volatile LifecycleManager lifecycleManager;
-	private volatile LocalAuthor localAuthor = null;
-	private volatile Group group = null;
 	private volatile MessageId parentId = null;
 	private volatile long timestamp = -1;
+	private volatile LocalAuthor localAuthor = null;
+	private volatile Group group = null;

 	@Override
 	public void onCreate(Bundle state) {
@@ -213,7 +214,9 @@ implements OnItemSelectedListener, OnClickListener {
 				try {
 					lifecycleManager.waitForDatabase();
 					long now = System.currentTimeMillis();
-					Collection<Group> groups = db.getSubscriptions();
+					Collection<Group> groups = new ArrayList<Group>();
+					for(Group g : db.getGroups())
+						if(!g.isPrivate()) groups.add(g);
 					long duration = System.currentTimeMillis() - now;
 					if(LOG.isLoggable(INFO))
 						LOG.info("Loading groups took " + duration + " ms");
@@ -341,7 +344,7 @@ implements OnItemSelectedListener, OnClickListener {
 				try {
 					lifecycleManager.waitForDatabase();
 					long now = System.currentTimeMillis();
-					db.addLocalGroupMessage(m);
+					db.addLocalMessage(m);
 					long duration = System.currentTimeMillis() - now;
 					if(LOG.isLoggable(INFO))
 						LOG.info("Storing message took " + duration + " ms");
--- a/briar-android/src/net/sf/briar/android/identity/CreateIdentityActivity.java
+++ b/briar-android/src/net/sf/briar/android/identity/CreateIdentityActivity.java
@@ -13,7 +13,6 @@ import static java.util.logging.Level.WARNING;
 import static net.sf.briar.android.util.CommonLayoutParams.MATCH_MATCH;
 import static net.sf.briar.android.util.CommonLayoutParams.WRAP_WRAP;

-import java.io.IOException;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;

@@ -123,13 +122,8 @@ implements OnEditorActionListener, OnClickListener {
 				KeyPair keyPair = crypto.generateSignatureKeyPair();
 				final byte[] publicKey = keyPair.getPublic().getEncoded();
 				final byte[] privateKey = keyPair.getPrivate().getEncoded();
-				LocalAuthor a;
-				try {
-					a = authorFactory.createLocalAuthor(nickname, publicKey,
-							privateKey);
-				} catch(IOException e) {
-					throw new RuntimeException(e);
-				}
+				LocalAuthor a = authorFactory.createLocalAuthor(nickname,
+						publicKey, privateKey);
 				storeLocalAuthor(a);
 			}
 		});