package Ġcom . re ode veloper . common Ċ Ċ import Ġcom . re ode veloper . mar vel pay . data . Specification ĊĊ Ċ interface ĠDataSource < T > Ġ{ ĊĠĠĠ Ġfun Ġstore ( item : T ) ĊĠĠĠ Ġfun Ġstore ( items : ĠList < T >) ĊĠĠĠ Ġfun ĠgetAll (): ĠList < T > ĊĠĠĠ Ġfun Ġquery List ( specification : ĠSpecification ): ĠList < T > ĊĠĠĠ Ġfun Ġquery Item ( specification : ĠSpecification ): ĠT Ċ }