VilleUI.java

package fi.utu.ville.exercises.model;

public interface VilleUI {
	
	/**
	 * Determines whether it is allowed to move away from the current view.
	 * 
	 * @return True if there are changes that would be lost if the view is changed. False if no changes will be lost or any changes made should not be saved
	 */
	public boolean isOkToExit();
	
	/**
	 * Change the current content. The user will be queried whether to discard any possible changed.
	 * 
	 * @param content
	 *            the content to change to
	 * @return true if the content change was successful, false otherwise.
	 */
	public boolean changeContent(VilleContent content);
	
	/**
	 * Changes the current content.
	 * 
	 * @param content
	 *            The new content.
	 * @param forceChange
	 *            if true, the user will not be prompted to save any changes made. If false, acts the same as the changeContent(VilleContent content) method.
	 * @return true if the content change was successful, false otherwise.
	 */
	public boolean changeContent(VilleContent content, boolean forceChange);
	
	/**
	 * Saves the current view in the view history stack.
	 */
	public void pushCurrentViewToStack();
	
	/**
	 * Restores the previous view from the history stack.
	 * 
	 * @return The previous view.
	 */
	public VilleContent restorePreviousViewFromStack();
	
	/**
	 * Draws the UI.
	 */
	public void doLayout();
	
	/**
	 * Clears all view history.
	 */
	public void clearPageStack();
	
	/**
	 * @return A String representation of the current page stack + the current page.
	 */
	public String getPageStack();
	
	/**
	 * Sets the help page to be shown in the help menu.
	 * 
	 * @param page
	 *            A valid url for the help page.
	 */
	public void setHelpPage(String page);
	
	/**
	 * Get the confirm dialog which is shown when the user attempts to leave the view but has changes that should be saved.
	 * 
	 * @return A confirm dialog.
	 */
	public DialogWithConfirm getConfirmExitDialog();
	
	/**
	 * Returns any information related to the current view in a human readable format suitable, for instance, displaying to ViLLE-users. Must not return any
	 * sensitive information (e.g. passwords, usernames or database ids)
	 * 
	 * @return A string displaying useful information about the view (e.g. assignment, round, course names), or the view's toString in case of a really boring
	 *         view.
	 */
	public default String getCurrentContentInformation() {
		return toString();
	}
	
	/**
	 * Hides/shows the ViLLE UI back button
	 * 
	 * @param visible
	 *            should the button be visible
	 */
	public void setBackButtonVisible(boolean visible);
	
	/**
	 * Enables/Disables the header bar in ViLLE
	 * 
	 * @param enabled
	 *            should the header bar be enabled
	 */
	public void setHeaderBarEnabled(boolean enabled);
}