How to implement multiple-level filters in an extensible manner?

Should make it extensible.

When I say make it extensible,I mean that the detail of filter options can be added later on with ease.

By design,it's better that parsing and rendering are independant.(?)

During parsing,need to show the next level filter o开发者_Go百科ptions if neccesary.

I mean it should be within filtering length of each filter label by "if neccesary".

How to make the detail of filtering options extensible when the detail of options is no neccesary?

For performance issue,should make all related fields in the same table.

For a live demo of the filters,see here.

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Have you looked at the Decorator pattern?