Kind of graph above look and not very is bad, we let increase a few character again below. Express phase of odd test and verify, you hope to be able to point out whether a control that express sheet is lawful. You accede again to control use code illegally other component, because this needs to produce many subclass again:

This kind not be too bad it seems that, let us increase a few new functions so. In structural effectiveness whether is in affirming, you need to point out a structure effective. You need to let you examine the code of effectiveness also can use other part, effectiveness test and verify need not undertake on more subclass again so.

Subclass spills over here is not only question. Think those reduplicative code, what you need to redesign you is whole kind of administrative levels. Have better method! Really, decorate implement mode is the good method that prevents this kind of situation.

Adornment implement on mode structure similar with acting mode (refer to the 2nd chapter) . An adornment implement the adduction that object reservation has pair of boy or girl friends, and dutiful is built afresh by the communal interface of ornament object. Adornment implement also can add a method, patulous by the interface of ornament object, aleatoric burden method, OK even conditional during script is carried out burden method.

Decorate for dug implement mode, let the library of the component that express sheet that face discussion crosses before us be exemple, and use adornment implement mode is not successive, implementation “lable” and “invalidation” two character.