AsyncTask.java

/*
 * Copyright 2014 Hannes Janetzek
 *
 * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
 *
 * This program is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free Software
 * Foundation, either version 3 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
package org.oscim.utils.async;

public abstract class AsyncTask extends Task {
	private TaskQueue mainloop;

	void setTaskQueue(TaskQueue mainloop) {
		this.mainloop = mainloop;
	}

	/**
	 * Do not override! Unless you have a reason, of course.
	 */
	@Override
	public void run() {
		if (state == GO) {
			/* running on worker thread */
			state = go(false);

			if (state == GO)
				/* run on worker again */
				mainloop.addTask(this);
			else
				mainloop.post(this);
		} else {
			/* post result on main-loop */
			onPostExecute(state);
		}
	}

	/**
	 * Executed on worker thread.
	 * 
	 * @return Task.DONE on success, Task.ERROR otherwise
	 */
	public abstract int go(boolean canceled);

	/**
	 * Executed on mainloop thread.
	 */
	public abstract void onPostExecute(int state);

}