package org.msh.tb.application.tasks;

import org.msh.tb.entities.User;
import org.msh.tb.entities.Workspace;

/**
 * Interface that all task must implement
 *
 * @author Ricardo Memoria
 */
public interface AsyncTask {

	/**
	 * Start the execution of the task
	 */
	void start();


	/**
	 * Cancel the execution of the task
	 */
	void cancel();


	/**
	 * Add a parameter to the task. This parameter may be used internally by the implemented task to get
	 * extra information about the execution
	 *
	 * @param param
	 * @param value
	 */
	void addParameter(String param, Object value);

	/**
	 * Return the value of a parameter given in the <code>addParameter</code> method
	 *
	 * @param param
	 * @return
	 */
	Object getParameter(String param);


	/**
	 * Return the current status of the task
	 *
	 * @return
	 */
	TaskStatus getStatus();


	/**
	 * Return the display name of the task to be read by the user
	 *
	 * @return
	 */
	String getDisplayName();


	/**
	 * Return the log message to be stored or displayed to the user
	 *
	 * @return
	 */
	String getLogData();


	/**
	 * Return true if the task must be logged
	 *
	 * @return
	 */
	boolean isLogged();


	/**
	 * Return the execution progress in terms of percentage (0 to 100%)
	 *
	 * @return
	 */
	double getProgress();


	/**
	 * Add a listener to a task in order to receive information about its execution
	 *
	 * @param taskListener
	 */
	void addListener(TaskListener taskListener);


	/**
	 * Remove a listener from a task
	 *
	 * @param taskListener
	 */
	void removeListener(TaskListener taskListener);


	/**
	 * Return the unique ID given by the task manager to this task
	 *
	 * @return
	 */
	String getId();


	/**
	 * Change the ID of the task
	 *
	 * @param id
	 */
	void setId(String id);

	/**
	 * Return the user that executed the task. If the task was executed by the system, this method returns null
	 *
	 * @return instance of the {@link User} class representing the user that executed the task.
	 */
	User getUser();

	/**
	 * Set the user that executed the task
	 *
	 * @param user
	 */
	void setUser(User user);

	/**
	 * Indicates if the task is unique in the execution list or if several instances of the same task
	 * can run simultaneously
	 *
	 * @return true if only one instance can run or false if several instances can run simultaneously
	 */
	boolean isUnique();

	/**
	 * Return workspace where task will be executed under
	 *
	 * @return
	 */
	Workspace getWorkspace();

	/**
	 * Set the workspace where task will be executed under
	 *
	 * @param ws
	 */
	void setWorkspace(Workspace ws);
}