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 list of the errors found in validation, each of which is the
	 *         <code>SemanticException</code> object.
	 */
	public final List validateWithContents( Module module )
	{
		ElementDefn elementDefn = (ElementDefn) getDefn( );
		List validatorList = ValidationExecutor.getValidationNodes( this,
				elementDefn.getTriggerDefnSet( ), true );
		ValidationExecutor executor = module.getValidationExecutor( );
		errors = executor.perform( this, validatorList );
		List list = new ArrayList( errors );
		int count = getDefn( ).getSlotCount( );
		for ( int i = 0; i < count; i++ )
		{
			Iterator iter = getSlot( i ).iterator( );
			while ( iter.hasNext( ) )
			{
				list.addAll( ( (DesignElement) iter.next( ) )
						.validateWithContents( module ) );
			}
		}
		return list;
	}
	/**
	 * Validates only this element without its contents, and return error list.
	 * The derived class should override this method to define specific
	 * validation rules.
	 * 
	 * @param module
	 *            the module