Package org.xj3d.core.loading

Class ContentLoadQueue

java.lang.Object

org.xj3d.core.loading.ContentLoadQueue

public class ContentLoadQueue
extends Object

Customized queue implementation specifically designed to handle the needs of X3D/VRML external content loading by compressing multi requests for the same URL into a single structure.

The queue sorts the incoming requests based on priority. The priority can be defined based on the value of the system property org.xj3d.core.loading.sort.order. See the package documentation for details on the value of this property. This can be changed at runtime and have the queue resorted by calling the requestResort() method called on this class.

Version:

$Revision: 1.6 $

Author:

Justin Couch

Method Summary

Modifier and Type	Method	Description
void	add(String loadConstantsType, String[] url, LoadRequestHandler loadRequestHandler, LoadDetails loadDetails)	Add the given load request onto the queue.
void	clear()	Clear the queue of items.
LoadRequest	getNext()	Get the next item from the queue.
void	purge()	Remove all elements from queue.
void	remove(String[] url, LoadDetails loadDetails)	Remove the given item from the queue.
void	requestResort()	If the sorting priority system property has changed, call this method to reload the property and force a resorting of the queue.
int	size()	Return the size of the queue.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

add

public void add(String loadConstantsType,
 String[] url,
 LoadRequestHandler loadRequestHandler,
 LoadDetails loadDetails)

Add the given load request onto the queue. If the URL is already sitting on the queue, the details will be inserted into the existing load request so that they may all be serviced at once.

Parameters:

loadConstantsType - The node loadConstantsType classification. One of the defined constants in LoadConstants.

url - The urls of the item to load

loadRequestHandler - The class that will process the load request once it is pulled grabbed from the queue for processing

loadDetails - Detail set for what should be loaded

Throws:

IllegalArgumentException - Either the URL list was null/zero length, or the loadConstantsType was null

getNext

public LoadRequest getNext()

Get the next item from the queue. Block until an item is available.

Returns:

The next item on the queue

size

public int size()

Return the size of the queue.

Returns:

size of queue

purge

public void purge()

Remove all elements from queue. Also unblock those who are waiting for items in the queue. They leave the getNext() method with null.

clear

public void clear()

Clear the queue of items. If there are users of the class that are blocked while waiting for elements in the queue, they remain so.

remove

public void remove(String[] url,
 LoadDetails loadDetails)

Remove the given item from the queue.

Parameters:

url - The url of the object to be removed

loadDetails - The instance of the detail to be removed from the URL

requestResort

public void requestResort()

If the sorting priority system property has changed, call this method to reload the property and force a resorting of the queue. This will not effect items that are currently being processed, only items that are waiting to be processed.