--- /dev/null
+/*
+ * Copyright 2005-2010 the original author or authors.
+ *
+ * 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 org.wamblee.security.authentication;
+
+import java.util.Set;
+
+/**
+ * Represents a set of users. Typical implementations would be an implementation
+ * based on a static configuration file or an implementation backed by a
+ * database.
+ *
+ * @author Erik Brakkee
+ */
+public interface UserSet {
+ /**
+ * Creates a user.
+ *
+ * @param aUsername
+ * User name.
+ * @param aPassword
+ * Password.
+ *
+ * @return New user.
+ *
+ * @throws UserMgtException
+ * In case the user cannot be created.
+ */
+ User createUser(String aUsername, String aPassword)
+ throws UserMgtException;
+
+ /**
+ * Must be called whenever a user object has been modified to notify the
+ * user set.
+ *
+ * @param aUser
+ * Modified user.
+ */
+ void userModified(User aUser);
+
+ /**
+ * Finds user.
+ *
+ * @param aName
+ * Username.
+ *
+ * @return User or null if not found.
+ */
+ User find(String aName);
+
+ /**
+ * Checks if a user exists.
+ *
+ * @param aUser
+ * User.
+ *
+ * @return True iff the user exists.
+ */
+ boolean contains(User aUser);
+
+ /**
+ * Adds a user. If the user already exists, the user details are updated
+ * with that of the specified user object.
+ *
+ * @param aUser
+ * User to add.
+ *
+ */
+ boolean add(User aUser);
+
+ /**
+ * Removes a user.
+ *
+ * @param aUser User to remove
+ * @return True iff user was removed.
+ *
+ */
+ boolean remove(User aUser);
+
+ /**
+ * Lists the current users.
+ *
+ * @return Users.
+ */
+ Set<User> list();
+
+ /**
+ * Lists the users belonging to a particular group.
+ *
+ * @param aGroup
+ * Group.
+ * @return Groups.
+ */
+ Set<User> list(Group aGroup);
+
+ /**
+ *
+ * @return The number of users.
+ */
+ int size();
+
+ /**
+ * Clears the user cache.
+ */
+ void clearCache();
+}