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/*
 * cron4j - A pure Java cron-like scheduler
 * 
 * Copyright (C) 2007-2010 Carlo Pelliccia (www.sauronsoftware.it)
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License version
 * 2.1, as published by the Free Software Foundation.
 *
 * 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 Lesser General Public License 2.1 for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License version 2.1 along with this program.
 * If not, see .
 */
package it.sauronsoftware.cron4j;

/**
 * LauncherThreads are used by {@link Scheduler} instances. A LauncherThread
 * retrieves a list of task from a set of {@link TaskCollector}s. Then it
 * launches, within a separate {@link TaskExecutor}, every retrieved task whose
 * scheduling pattern matches the given reference time.
 * 
 * @author Carlo Pelliccia
 * @since 2.0
 */
class LauncherThread extends Thread {

	/**
	 * A GUID for this object.
	 */
	private String guid = GUIDGenerator.generate();

	/**
	 * The owner scheduler.
	 */
	private Scheduler scheduler;

	/**
	 * Task collectors, used to retrieve registered tasks.
	 */
	private TaskCollector[] collectors;

	/**
	 * A reference time for task launching.
	 */
	private long referenceTimeInMillis;

	/**
	 * Builds the launcher.
	 * 
	 * @param scheduler
	 *            The owner scheduler.
	 * @param collectors
	 *            Task collectors, used to retrieve registered tasks.
	 * @param referenceTimeInMillis
	 *            A reference time for task launching.
	 */
	public LauncherThread(Scheduler scheduler, TaskCollector[] collectors,
                          long referenceTimeInMillis) {
		this.scheduler = scheduler;
		this.collectors = collectors;
		this.referenceTimeInMillis = referenceTimeInMillis;
		// Thread name.
		String name = "cron4j::scheduler[" + scheduler.getGuid()
				+ "]::launcher[" + guid + "]";
		setName(name);
	}

	/**
	 * Returns the GUID for this object.
	 * 
	 * @return The GUID for this object.
	 */
	public Object getGuid() {
		return guid;
	}

	/**
	 * Overrides {@link Thread#run()}.
	 */
	public void run() {
		outer: for (int i = 0; i < collectors.length; i++) {
			TaskTable taskTable = collectors[i].getTasks();
			int size = taskTable.size();
			for (int j = 0; j < size; j++) {
				if (isInterrupted()) {
					break outer;
				}
				SchedulingPattern pattern = taskTable.getSchedulingPattern(j);
				if (pattern.match(scheduler.getTimeZone(), referenceTimeInMillis)) {
					Task task = taskTable.getTask(j);
					scheduler.spawnExecutor(task);
				}
			}
		}
		// Notifies completed.
		scheduler.notifyLauncherCompleted(this);
	}
}