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/api/command/ExtendsException.java
{
		if ( sResourceKey == DESIGN_EXCEPTION_NOT_FOUND
				|| sResourceKey == DESIGN_EXCEPTION_CANT_EXTEND
				|| sResourceKey == DESIGN_EXCEPTION_PARENT_NOT_IN_COMPONENT )
		{
			return ModelMessages.getMessage( sResourceKey,
					new String[]{extendsName} );
		}
		else if ( sResourceKey == DESIGN_EXCEPTION_WRONG_TYPE
				|| sResourceKey == DESIGN_EXCEPTION_CIRCULAR
				|| sResourceKey == DESIGN_EXCEPTION_WRONG_EXTENSION_TYPE )
		{
			return ModelMessages.getMessage( sResourceKey, new String[]{
					getElementName( parent ), getElementName( element )} );
		}
		else if ( sResourceKey == DESIGN_EXCEPTION_SELF_EXTEND
				|| sResourceKey == DESIGN_EXCEPTION_EXTENDS_FORBIDDEN
				|| sResourceKey == DESIGN_EXCEPTION_NO_PARENT )
		{
			return ModelMessages.getMessage( sResourceKey,
					new String[]{getElementName( element )} );
		}
		else if ( sResourceKey == DESIGN_EXCEPTION_PARENT_NOT_INCLUDE )
		{
			return ModelMessages.getMessage( sResourceKey, new String[]{parent
					.getIdentifier( )} );
		}
		return ModelMessages.getMessage( sResourceKey );
	}
}