Bug 138562 Splite extendsexcpetion to seperate sub class
The suggestion is Parent invalid Cycle extends Different type extends Not top level extends
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/DesignElement.java
* @return the identifier of this element
	 */
	public String getIdentifier( )
	{
		if ( getName( ) != null )
		{
			StringBuffer sb = new StringBuffer( );
			sb.append( getDefn( ).getDisplayName( ) );
			sb.append( "(\"" ); 
			sb.append( getName( ) );
			sb.append( "\")" ); 
			return sb.toString( );
		}
		if ( this instanceof ReportDesign )
			return "report"; 
		else if ( this instanceof Library )
			return "library"; 
		if ( getContainer( ) == null )
			return getDefn( ).getName( );
		ContainerSlot slot = getContainer( ).getSlot( getContainerSlot( ) );
		ISlotDefn slotDefn = getContainer( ).getDefn( ).getSlot(
				getContainerSlot( ) );
		StringBuffer sb = new StringBuffer( );
		sb.append( getContainer( ).getIdentifier( ) );
		sb.append( "." ); 
		sb.append( slotDefn.getDisplayName( ) );
		sb.append( "[" ); 
		sb.append( slot.findPosn( this ) );
		sb.append( "]" ); 
		return sb.toString( );