/*******************************************************************************
 * Copyright (C) 2013 JMaNGOS <http://jmangos.org/>
 * 
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 * 
 * You should have received a copy of the GNU General Public License along
 * with this program. If not, see <http://www.gnu.org/licenses/>.
 ******************************************************************************/
package org.jmangos.commons.task;

import java.util.concurrent.Future;

import javolution.util.FastMap;

/**
 * The Class TaskManager.
 * 
 */
public class TaskManager {

    /** all tasks. */
    private final FastMap<TaskId, Future<?>> tasks = new FastMap<TaskId, Future<?>>().shared();

    /**
     * Gets the task.
     * 
     * @param taskId
     *        the task id
     * @return the task
     */
    public Future<?> getTask(final TaskId taskId) {

        return this.tasks.get(taskId);
    }

    /**
     * Checks for task.
     * 
     * @param taskId
     *        the task id
     * @return true, if successful
     */
    public boolean hasTask(final TaskId taskId) {

        return this.tasks.containsKey(taskId);
    }

    /**
     * Cancel task.
     * 
     * @param taskId
     *        the task id
     */
    public void cancelTask(final TaskId taskId) {

        final Future<?> task = this.tasks.remove(taskId);
        if (task != null) {
            task.cancel(false);
        }
    }

    /**
     * If task already exist - it will be canceled.
     * 
     * @param taskId
     *        the task id
     * @param task
     *        the task
     */
    public void addTask(final TaskId taskId, final Future<?> task) {

        cancelTask(taskId);
        this.tasks.put(taskId, task);
    }

    /**
     * If task already exist - it will not be replaced.
     * 
     * @param taskId
     *        the task id
     * @param task
     *        the task
     */
    public void addNewTask(final TaskId taskId, final Future<?> task) {

        this.tasks.putIfAbsent(taskId, task);
    }

    /**
     * Cancel all tasks and remove from map.
     */
    public void cancelAllTasks() {

        for (final TaskId taskId : this.tasks.keySet()) {
            final Future<?> task = this.tasks.remove(taskId);
            if (task != null) {
                task.cancel(true);
            }
        }
    }

    /**
     * Cancel all tasks and remove from map based on task's priority.
     * 
     * @param priority
     *        the priority
     */
    public void cancelAllTasks(final TaskPriority priority) {

        for (final TaskId taskId : this.tasks.keySet()) {
            if (taskId.getPriority().ordinal() >= priority.ordinal()) {
                final Future<?> task = this.tasks.remove(taskId);
                if (task != null) {
                    task.cancel(true);
                }
            }
        }
    }
}