[CONFIGURATION-248] Safeguard config source abstraction by using HierarchicalConfiguration as supertype for all configs

• Type: Wish
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.3
• Fix Version/s: 2.x

Environment

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• Assignee: Unassigned
• Reporter: Dennis Kuehn
• Created: 11/Jan/07 13:30
• Updated: 24/Mar/16 20:13

Description

I hope I get this right:
When I have a CompositeConfiguration, the nice thing about it is that I don't have to care in which file or file type a config entry has been defined. Now when part of my CompositeConfiguration has a hierarchical structure and I need the API provided by HierarchicalConfiguration, I lose the aforementioned abstraction: I need to cast a specific part of my CompositeConfiguration to HierarchicalConfiguration. This is a major design problem!

It would be better to leverage the Composite Pattern here: derive all configuration classes from HierarchicalConfiguration. Put differently, move the HierarchicalConfiguration API to Configuration. Even if a config is not hierarchically structured, methods for hierarchical access will be present, but that's a minor drawback which is intrinsic to the Composite Pattern. This also happens when you are modelling a tree structure and you have a common supertype "Node" which has a method "getSubNodes()" which will also be present in leaf node instances (in this case, "getSubNodes()" would return null etc.).