Rewrite our build as modular maven components

This refactoring splits the code up into different components, with
their own per-component CLASSPATH.  By moving all of our classes
into isolated components we can better isolate the classpaths and
try to avoid unexpected dependency problems.  It also allows us to
more clearly define which components are used by the GWT UI and
thus must be compiled under GWT, and which components are run on
the server and can therefore use more of the J2SE API.

Change-Id: I833cc22bacc5655d1c9099ed7c2b0e0a5b08855a
Signed-off-by: Shawn O. Pearce <sop@google.com>

gerrit-server/src/main/java/com/google/gerrit/server/account/Realm.java

@@ -0,0 +1,46 @@
+// Copyright (C) 2009 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.account;
+
+import com.google.gerrit.reviewdb.Account;
+import com.google.gerrit.reviewdb.AccountGroup;
+
+import java.util.Set;
+
+public interface Realm {
+  /** Can the end-user modify this field of their own account? */
+  public boolean allowsEdit(Account.FieldName field);
+
+  public AuthRequest authenticate(AuthRequest who) throws AccountException;
+
+  public void onCreateAccount(AuthRequest who, Account account);
+
+  public Set<AccountGroup.Id> groups(AccountState who);
+
+  /**
+   * Locate an account whose local username is the given account name.
+   * <p>
+   * Generally this only works for local realms, such as one backed by an LDAP
+   * directory, or where there is an {@link EmailExpander} configured that knows
+   * how to convert the accountName into an email address, and then locate the
+   * user by that email address.
+   */
+  public Account.Id lookup(String accountName);
+
+  /**
+   * Search for matching external groups.
+   */
+  public Set<AccountGroup.ExternalNameKey> lookupGroups(String name);
+}