source: branches/autoquest-core-tasktrees-alignment/src/main/java/de/ugoe/cs/autoquest/tasktrees/manager/TaskTreeManager.java

//   Copyright 2012 Georg-August-Universität Göttingen, Germany
//
//   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 de.ugoe.cs.autoquest.tasktrees.manager;

import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
import java.util.logging.Level;

import de.ugoe.cs.autoquest.eventcore.Event;
import de.ugoe.cs.autoquest.tasktrees.treeifc.IEventTask;
import de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskModel;
import de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskBuilder;
import de.ugoe.cs.autoquest.tasktrees.treeifc.ITaskFactory;
import de.ugoe.cs.autoquest.tasktrees.treeifc.IUserSession;
import de.ugoe.cs.util.console.Console;

// TODO: Auto-generated Javadoc
/**
 * <p>
 * The task tree manager is responsible for transforming one or more user
 * sessions into a task model. It can be called by providing a collection of
 * user sessions where the result will be a task model. Furthermore, it can be
 * used by providing single events in their respective order including
 * notifications about where a user session ends. The result is a task model, as
 * well.
 * </p>
 *
 * @author pharms
 * @version 1.0
 */
public class TaskTreeManager {

        /** <p> the internally used task builder </p>. */
        private final ITaskBuilder taskBuilder = ComponentManager
                        .getDefaultTaskBuilder();

        /** <p> the internally used task factory </p>. */
        private final ITaskFactory taskFactory = ComponentManager
                        .getDefaultTaskFactory();

        /** <p> if single events are provided, the user sessions collected so far </p>. */
        private List<IUserSession> sessions = null;

        /** <p> if single events are provided, the currently collected user session </p>. */
        private IUserSession currentSession = null;

        /**
         * <p>
         * initializes the task tree manager
         * </p>.
         */
        public TaskTreeManager() {
                sessions = new LinkedList<IUserSession>();
        }

        /**
         * <p>
         * internally asserts that there is a current session to add new events to
         * </p>.
         */
        private void assertSessionSequence() {
                if (currentSession == null) {
                        currentSession = taskFactory.createUserSession();
                }
        }

        /**
         * <p>
         * creates a task model based on the provided user sessions. Yet, the user
         * sessions are list of events. Such will be transformed in into task
         * instances of event tasks assigned to {@link IUserSession}s. The
         * {@link IUserSession}s will then be restructured using the temporal
         * relationship rule manager to detect tasks and respective instances. The
         * results of this transformation is stored in a task model which is the
         * return value of this method.
         * </p>
         *
         * @param newSessions            the user sessions of which the task model shall be created
         * @return the task model created from the user sessions
         */
        public synchronized ITaskModel createTaskModel(
                        Collection<List<Event>> newSessions) {
                if ((currentSession != null) || (sessions.size() > 0)) {
                        throw new IllegalStateException(
                                        "do not mix calls to this method with calls to the "
                                                        + "other methods for handling tasks. Use only one "
                                                        + "variant instead.");
                }

                for (final List<Event> newSession : newSessions) {
                        if (newSession.size() > 0) {
                                for (final Event event : newSession) {
                                        handleNewEvent(event);
                                }
                                finishSession();
                        }
                }

                return getTaskModel();
        }

        /**
         * <p>
         * used to denote, that all previously added events using
         * {@link #handleNewEvent(Event)} belong to the same session and that this
         * session is now complete. All further events will be added to a new
         * session which may be ended using this method, as well.
         * </p>
         */
        public void finishSession() {
                if ((currentSession != null) && (currentSession.size() > 0)) {
                        sessions.add(currentSession);
                        currentSession = null;
                }
        }

        /**
         * <p>
         * returns the task model, that belongs to the events in the user sessions
         * collected so far.
         * </p>
         * 
         * @return the task model
         */
        public synchronized ITaskModel getTaskModel() {
                finishSession();

                Console.traceln(Level.INFO,
                                "applying temporal relationship generation rules");

                ComponentManager.getTemporalRelationshipRuleManager().applyRules(
                                sessions);

                return taskFactory.createTaskModel(sessions);
        }

        /**
         * <p>
         * handles a single event that occurred in a user session.
         * </p>
         * 
         * @param event
         *            the event to handle
         */
        public void handleNewEvent(Event event) {
                assertSessionSequence();
                final String description = event.getType().getName() + " \u21D2 "
                                + event.getTarget();
                final IEventTask eventTask = taskFactory
                                .createNewEventTask(description);
                taskBuilder.addExecutedTask(currentSession,
                                taskFactory.createNewTaskInstance(eventTask, event));
        }

}