com.threerings.crowd.client.PlaceView Maven / Gradle / Ivy
//
// $Id$
//
// Narya library - tools for developing networked games
// Copyright (C) 2002-2012 Three Rings Design, Inc., All Rights Reserved
// http://code.google.com/p/narya/
//
// 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
package com.threerings.crowd.client;
import com.threerings.crowd.data.PlaceObject;
/**
* This interface provides a convenient means for decoupling user
* interface components that interact with a place object and that need to
* keep themselves up to date when the client moves from place to place.
*
* In general, such components need to know when the client is about
* to enter a place so that they can subscribe if necessary or at least
* extract information about the place. They also need to know when a
* client has left a place so that they can unsubscribe and clean up after
* themselves. This is the information that the place view interface makes
* available to them in a decoupled way.
*
*
The part of the client implementation that is responsible for the
* main user interface can act as a location observer, and it can make use
* of {@link PlaceViewUtil} to dispatch notification of place changes to
* every PlaceView implementing user interface element in the
* user interface hierarchy with calls to {@link
* PlaceViewUtil#dispatchWillEnterPlace} and {@link
* PlaceViewUtil#dispatchDidLeavePlace}. These functions traverse the UI
* hierarchy (starting with the element provided which would generally be
* the top-level UI element, and dispatch calls to {@link #willEnterPlace}
* and {@link #didLeavePlace} respectively on any UI element they find
* that implements PlaceView.
*
*
By doing this, the client code can simply create place-sensitive
* user interface elements and stick them in the user interface and
* essentially forget about them, knowing that they will all be notified
* of place entering and exiting by virtue of the single dispatching
* calls. It is useful to note that place-sensitive user interface
* elements will also generally need a reference to the {@link
* com.threerings.crowd.util.CrowdContext} derivative in use by
* the client, but those are best supplied at construct time.
*/
public interface PlaceView
{
/**
* Called when the client has entered a place and is about to display
* the user interface for that place.
*
* @param plobj the place object that was just entered.
*/
void willEnterPlace (PlaceObject plobj);
/**
* Called after the client has left a place and needs to clean up
* after the user interface that was displaying that place.
*
* @param plobj the place object that was just left.
*/
void didLeavePlace (PlaceObject plobj);
}