/*
 * Bibliothek - DockingFrames
 * Library built on Java/Swing, allows the user to "drag and drop"
 * panels containing any Swing-Component the developer likes to add.
 * 
 * Copyright (C) 2010 Benjamin Sigg
 * 
 * This library 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 2.1 of the License, or (at your option) any later version.
 *
 * This library 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 library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Benjamin Sigg
 * benjamin_sigg@gmx.ch
 * CH - Switzerland
 */
package bibliothek.gui.dock.frontend;

import bibliothek.gui.DockFrontend;
import bibliothek.gui.Dockable;
import bibliothek.gui.dock.DockElement;
import bibliothek.gui.dock.perspective.Perspective;
import bibliothek.gui.dock.perspective.PerspectiveElement;
import bibliothek.gui.dock.perspective.PerspectiveStation;

/**
 * This cache is used by a {@link DockFrontend} to create a {@link Perspective}. The strategy
 * will be provided with the registered {@link DockElement}s of the frontend (root-stations and
 * dockables) and has to convert them into {@link PerspectiveElement}s.  
 * @author Benjamin Sigg
 */
public interface FrontendPerspectiveCache {
	/**
	 * Given an <code>element</code> that was earlier created by the client and added to a 
	 * {@link DockFrontend}, this method converts <code>element</code> to a {@link PerspectiveElement}.<br>
	 * When called multiple times with the same arguments, then this method is free to either return
	 * different objects or to always return the same object.<br>
	 * @param id the unique identifier under which <code>element</code> is known to the {@link DockFrontend}
	 * @param element the element whose perspective must be created
	 * @param isRootStation whether <code>element</code> is registered as root-station at the {@link DockFrontend}
	 * or as {@link Dockable}
	 * @return the perspective, must not be <code>null</code>
	 */
	public PerspectiveElement get( String id, DockElement element, boolean isRootStation );
	
	/**
	 * Called to convert <code>id</code> to a {@link PerspectiveElement}. This method will only be called
	 * with identifiers that were not used for {@link #get(String, DockElement, boolean)}.
	 * @param id the identifier of some element
	 * @param rootStation whether <code>id</code> represents a root-station or not
	 * @return the element, can be <code>null</code> 
	 */
	public PerspectiveElement get( String id, boolean rootStation );
	
	/**
	 * Gets the unique identifier of <code>element</code>.
	 * @param element some element, can be either a dockable or a root-station
	 * @return the unique identifier or <code>null</code> if this cache is unable to associate <code>element</code> 
	 * with an identifier. Should not be <code>null</code> for elements that were created by
	 * {@link #get(String, boolean)} or {@link #get(String, DockElement, boolean)}.
	 */
	public String get( PerspectiveElement element );
	
	/**
	 * Tells whether <code>station</code> is supposed to be a root-station.
	 * @param station the element which may be a root-station
	 * @return <code>true</code> if <code>station</code> should be treated as root-station
	 */
	public boolean isRootStation( PerspectiveStation station );
}