Bug 139110 GUI enhancement to support create subquery more conveniently.
Description: GUI enhancement to support create subquery more conveniently. Steps to reproduce: Subquery means insert table/list inside another table/list item, and the inner table/list item doesn't has its own dataset binding. In latest build, if you want to creat a subquery structure, you have to use dataSetRow as binding expression for data items in inner table/list item. For example: 1. Insert a list, generate column data binding for it. 2. Add a group for the list. 3. Insert table to list group header which is used to display data rows in list group. Dont' bind table to dataset. 4. Insert a data to table detail row. 5. New a binding column for data, click to Open Expression Builder. The issue is that only "Availabel column bindings" is listed in Category but no "Available Data Sets". So I have to type dataSetRow[".."] by myself to generate correct subquery. For users, maybe they will mistakenly use "Available column bindings" which will generate expression like row._outer[".."] and get wrong result. So it is recommended to add "Available Data Sets" in Expression Builder for such case.
UI/org.eclipse.birt.report.designer.core/src/org/eclipse/birt/report/designer/util/DEUtil.java
}
		
		List availableList = new ArrayList( );
		for ( int i = 0; i < list.size( ); i++ )
		{
			if ( parent.canContain( slotId,
					( (IElementDefn) list.get( i ) ).getName( ) ) )
			{
				availableList.add( list.get( i ) );
			}
		}
		return availableList;
	}
	/**
	 * Get the containable element type list of give slot handle
	 * 
	 * @param slotHandle
	 */
	public static List getElementSupportList( SlotHandle slotHandle )
	{
		return getElementSupportList( slotHandle.getElementHandle( ),
				slotHandle.getSlotID( ) );
	}
	/**
	 * Gets the support list of the given parent element. The slotID is decided
	 * by the parent element.
	 * 
	 * @param parent
	 *            the parent element
	 * @return the the support list of the element