playablegroup.as

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								else {
									secondary.start();
								}
							}
							break;
					}
				}
			}
			// Saved until after possible play-state changes. Now we can base listening on this group's state.
			_children[ item ] = false;
			if (_state!=STOPPED)
				listenTo(item);
			return true;
		}
		
		/**
		 * Removes a single IPlayable from the children array.
		 * 
		 * <p>Note that if play is in progress when a child is added it does not
		 * interrupt play and the child is monitored for completion along with
		 * others.</p>
		 * 
		 * @param item		Any instance that implements IPlayable and uses PlayableBase's play-state constants.
		 * @return Success.
		 */
		public function removeChild(item:IPlayable): Boolean {
			var v:* = _children[ item ];
			if (v===null)
				return false;
			if (v===true)
				unListenTo( item );
			delete _children[ item ];
			return true;
		}
		
		/**
		 * Test whether any child has a particular play state, based on 
		 * the int constants in the PlayableBase class.
		 * 
		 * <pre>
		 * // Example: resume a paused group
		 * if ( myGroup.anyChildHasState(PlayableBase.PAUSED) ) {
		 *     myGroup.resume();
		 * }
		 * </pre>
		 */
		public function anyChildHasState(state:String): Boolean {
			for (var item:Object in _children)
				if ((item as IPlayable).state==state)
					return true;
			return false;
		}
		
		// -== IPlayable implementation ==-
		
		/**
		 * Calls start on all children. 
		 * 
		 * <p>If the group is active when this method is called, a <code>stop</code> call 
		 * is automated which will result in a GoEVent.STOP event being dispatched.</p>
		 * 
		 * @return Returns true if any child in the group starts successfully.
		 */
		public function start() : Boolean {
			stop();
			var r:Boolean = false;
			for (var item:Object in _children) {
				var started:Boolean = (item as IPlayable).start();
				if (started)
					listenTo(item as IPlayable);
				r = (started || r);
			}
			if (!r) return false; // all starts failed
			_state = PLAYING;
			dispatchEvent(new GoEvent( GoEvent.START));
			_playRetainer[ this ] = 1; // Developers - Important! Look up _playRetainer.
			return true;
		}

		/**
		 * If the group is active, this method stops all child items and 
		 * dispatches a GoEvent.STOP event.
		 * 
		 * @return Returns true only if all children in the group stop successfully.
		 */
		public function stop() : Boolean {
			if (_state == STOPPED)
				return false;
			_state = STOPPED;
			_repeater.reset();
			delete _playRetainer[ this ]; // Developers - Important! Look up _playRetainer.
			if (_listeners==0) {
				dispatchEvent(new GoEvent( GoEvent.COMPLETE ));
				return true;
			}
			var r:Boolean = true;
			for (var item:Object in _children) {
				unListenTo(item as IPlayable);
				r = ((item as IPlayable).stop() && r);
			}
			dispatchEvent(new GoEvent( GoEvent.STOP ));
			return r;
		}
		
		/**
		 * Calls <code>pause</code> on all children.
		 * 
		 * @return  Returns true only if all playing children in the group paused successfully
		 * 			and at least one child was paused.
		 */
		public function pause() : Boolean {
			if (_state!= PLAYING)
				return false;
			var r:Boolean = true;
			var n:uint = 0;
			for (var item:Object in _children) {
				var success:Boolean = (item as IPlayable).pause();
				if (success) n++;
				r = (r && success);
			}
			if (n>0) {
				_state = PAUSED; // state should reflect that at least one item was paused,
								  // while return value may indicate that not all pause calls succeeded.
				dispatchEvent(new GoEvent( GoEvent.PAUSE ));
			}
			return (n>0 && r);
		}
		
		/**
		 * Calls <code>resume</code> on all children.
		 * 
		 * @return	Returns true only if all paused children in the group resumed successfully
		 * 			and at least one child was resumed.
		 */
		public function resume() : Boolean {
			if (_state!= PAUSED)
				return false;
			var r:Boolean = true;
			var n:uint = 0;
			for (var item:Object in _children) {
				var success:Boolean = (item as IPlayable).resume();
				if (success) n++;
				r = (r && success);
			}
			if (n>0) {
				_state = PLAYING; // state should reflect that at least one item was resumed,
								  // while return value may indicate that not all resume calls succeeded.
				dispatchEvent(new GoEvent( GoEvent.RESUME ));
			}
			return (n>0 && r);
		}
		
		/**
		 * Calls <code>skipTo</code> on all children.
		 * 
		 * @return	Returns true only if all children in the group skipTo the position successfully
		 * 			and at least one child was affected.
		 */
		public function skipTo(position : Number) : Boolean {
			var r:Boolean = true;
			var n:uint = 0;
			position = _repeater.skipTo(_repeater.cycles, position); // TODO: TEST
			for (var item:Object in _children) {
				r = ((item as IPlayable).skipTo(position) && r);
				listenTo(item as IPlayable);
				n++;
			}
			_state = (r ? PLAYING : STOPPED);
			return (n>0 && r);
		}
		
		// -== Protected Methods ==-
		
		/**
		 * @private
		 * Internal handler for item completion.
		 * @param event		GoEvent dispatched by child item. 
		 */
		protected function onItemEnd(event:GoEvent) : void {
			unListenTo(event.target as IPlayable);
			if (_listeners==0) {
				complete();
			}
		}
		
		/**
		 * @private
		 * Internal handler for group completion.
		 */
		protected function complete() : void {
			if (_repeater.next()) {
				dispatchEvent(new GoEvent( GoEvent.CYCLE ));
				for (var item:Object in _children) {
					var started:Boolean = (item as IPlayable).start();
					if (started)
						listenTo(item as IPlayable);
				}
			}
			else {
				stop();
			}
		}

		/**
		 * @private
		 * Internal. Listen for item completion, keeping tight track of listeners.
		 * @param item	Any instance that extends IPlayable (IPlayable itself should not be used directly).
		 */
		protected function listenTo(item:IPlayable) : void {
			if (_children[ item ] === false) {
				item.addEventListener(GoEvent.STOP, onItemEnd, false, 0, true);
				item.addEventListener(GoEvent.COMPLETE, onItemEnd, false, 0, true);
				_children[ item ] = true;
				_listeners++;
			}
		}
		
		/**
		 * @private
		 * Internal. Stop listening for item completion.
		 * @param item	Any instance that extends IPlayable (IPlayable itself should not be used directly).
		 * @return Number of completion listeners remaining.
		 */
		protected function unListenTo(item:IPlayable) : void {
			if (_children[ item ] === true) {
				item.removeEventListener(GoEvent.STOP, onItemEnd);
				item.removeEventListener(GoEvent.COMPLETE, onItemEnd);
				_children[ item ] = false;
				_listeners--;
			}
		}
	}
}