LazyLoadable.java

/**
 * Copyright (c) 2003-2009, Xith3D Project Group all rights reserved.
 * 
 * Portions based on the Java3D interface, Copyright by Sun Microsystems.
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package org.xith3d.scenegraph;

/**
 * A LazyLoadable is a class that is able to be constructed
 * and teared down asynchronously on demand.
 * 
 * This interface is typically implemented by Nodes passed to a LODSwitch.
 * 
 * @author Mathias Henze (aka cylab)
 */
public interface LazyLoadable
{
    /**
     * Returns whether this instance is already set up, so it can be used right away.
     * @return true, if the instance is fully set up, false otherwise
     */
    boolean isSetUp();
    
    /**
     * This method will be called by the engine on a dedicated thread (not the rendering thread)
     * to allow the background construction of a Node. The Node will not be displayed until this
     * method returns.
     * 
     * Prepare may be called multiple times, even if the instance is already set up and tearDown()
     * wasn't called, so implementation have to check, if they are already set up and return immediatly
     */
    void prepare();
    
    /**
     * This method will be called by the engine on the rendering thread to to allow thread safe attachment
     * of the constructed content to the scenegraph. This method will be called after prepare().
     */
    void setUp();
    
    /**
     * This method will be called by the engine on the rendering thread to to allow thread safe detachment
     * of the content from the scenegraph. The Node will be hidden before.
     */
    void tearDown();
    
    /**
     * This method will be called by the engine on a dedicated thread (not the rendering thread)
     * to allow the background destruction of a Node. This method will be called after tearDown().
     */
    void cleanUp();
}