/*

File: URLLoading.h

Abstract: A Class controlling loading multiple URLs.

Version: 1.0

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*/

#import <Cocoa/Cocoa.h>

#import <URLDataReceiver.h>

/*!

 * @abstract Container of URLDataReceiver instances.

 *

 * This class control the loading of multiple URLs in an asynchronous fashion.

 */

@interface URLLoader : NSObject {

    NSMutableDictionary* fFinished; /**< Receivers that have finished.*/

    NSMutableDictionary* fPending; /**< Receivers that have not started or currently are loading.*/

    id fDelegate;

    NSRecursiveLock* fLock;

}

/*!

 * Delegate must conform to URLLoaderDelegate protocol.

 */

- (id)initWithDelegate:(id)delegate;

/*!

 * @abstract Start loading data.

 */

- (void)load:(NSArray*)URLs;

/*!

 * @abstract Cancel loading.

 *

 * Both fFinished and fPending will be cleared.

 */

- (void)cancel;

/*!

 * @abstract Currently reset has the same effect as cancel.

 */

- (void)reset;

/*!

 * @abstract Return the data from URL specified by aURL.

 *

 * Once loading finished, data receiver is stored in fFinished and indexed by

 * corresponding URL.

 */

- (NSData*)dataForURL:(NSURL*)aURL;

/*!

 * @abstract Return [fFnished objectEnumerator]

 */

- (NSEnumerator*)dataEnumerator;

/*!

 * @abstract Return [fFinished keyEnumerator];

 */

- (NSEnumerator*)urlEnumerator;

@end

/*!

 * @abstract URLLoaderDelegate protocol.

 */

@interface NSObject(URLLoaderDelegate)

/*!

 * @abstract Notify delegate that aURL has started loading.

 */

- (void)URLLoader:(URLLoader*)theURLLoader didBeginURL:(NSURL*)aURL;

/*!

 * @abstract Notify delegate that aURL has finished loading.

 */

- (void)URLLoader:(URLLoader*)theURLLoader didFinishURL:(NSURL*)aURL;

/*!

 * @abstract Notify delegate that all URLs have finished loading.

 */

- (void)URLLoaderDidFinishAll:(URLLoader*)theURLLoader;

@end