Java design pattern: Appearance mode facade

Facade appearance mode

The appearance mode----provides a unified interface for a group of subsystems, which defines a higher-level interface that makes the subsystem easier to use.

Borrow "Big talk Design Model" in the example: there are more than n stocks in the market, when investors want to buy stocks in order to maximize their earnings need to investigate many kinds of stocks on the market, and then according to their own judgment to choose a few stock portfolio purchase (this scenario, each stock can be purchased separately, users need to investigate, Select a group of shares to purchase together). And some users directly buy funds, the role of the Fund is to help users select a few stocks to combine the purchase, users do not have to choose more than one stock.

In this scenario: buying a single stock separately is an atomic operation, and the Fund is equivalent to providing an interface to the user, which encapsulates the atomic operation of a plurality of buy stocks, which is the appearance pattern.

Java design pattern: Appearance mode facade