Bug 130495 Get rid of SessionHandleAdapter
Now, we use SessionHandleAdapter to keep current active report deisng. That's a bad practive for editor swith and rebuild will cuase lots of problmes. Need find way to replace it.
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/core/model/SessionHandleAdapter.java
*/
	public MasterPageHandle getMasterPageHandle( ModuleHandle handle )
	{
		SlotHandle slotHandle = handle.getMasterPages( );
		Iterator iter = slotHandle.iterator( );
		return (MasterPageHandle) iter.next( );
	}
	/**
	 * 
	 * @param handle
	 *            the model
	 * @return get corresponding mediator
	 */
	public ReportMediator getMediator( ModuleHandle handle )
	{
		if ( handle != null )
		{
			handle.addDisposeListener( disposeLitener );
		}
		ReportMediator mediator = (ReportMediator) mediatorMap.get( handle );
		if ( mediator == null )
		{
			mediator = new ReportMediator( );
			mediatorMap.put( handle, mediator );
		}
		return mediator;
	}
	/**
	 * @return the current mediator
	 */