Software engineering – sequence diagram operation


1. (others)

S company has set up an online e-commerce website, which mainly provides online commodity sales functions for registered merchants. In order to better attract users, s company plans to provide commodity promotion function for registered merchants. Different categories of goods will lead to different promotion methods and contents.

Registered merchants can publish promotion information. Merchants should first select a specific category involved in promotion among the categories of goods they sell, then select one or more goods of this category (a commodity only belongs to one category), and then formulate a more favorable discount policy and the preferential time of promotion activities. Finally, the system generates promotion information and publishes the promotion information on the website.

After the merchant releases the promotion information, the registered users of the website can purchase the promotion products through the website. Users can choose to participate in a promotion activity, select specific promotional commodities, and enter purchase information such as purchase quantity. The system generates a corresponding promotion order. As long as the user confirms to pay the promotion order online (i.e. complete the payment) through the online payment system provided by the website within the time range of the preferential activity, the purchase activity of goods can be completed at a preferential price, otherwise the promotion order will become invalid.

2. (others)

A bank plans to develop an ATM system The system reads the ATM card through the card reader, and the interaction between the system and the customer is realized by the customer console; The bank operator can control system startup and system shutdown; The system communicates with the bank through the network.

When the card reader judges that the user has inserted an ATM card, it creates a session. After the session starts, the card reader reads the card and asks the customer to enter the personal verification code (PIN). The system sends the card number and personal verification code information to the banking system for verification. After the verification is passed, the customer can select the following transaction from the menu:

1. Withdrawal from ATM card account (withdraw);

2. Deposit card;

3. Transfer;

4. Inquire about ATM card account information.

A session can contain multiple transactions, and each transaction will also send the card number and personal verification code information to the banking system for verification. If the personal verification code is wrong, it will be transferred to the personal verification code error processing (invalid pin process). After each transaction is completed, the customer can choose to continue the above transaction or return the card. When you choose to return the card, the system pops up the ATM card and the session ends.

3. (others)

The architecture of a fingerprint access control system is shown in the figure below. Its main components include: mainframe, lockcontroller, fingerprint reader and lock.


The system can realize the following behaviors:

1. Each electric lock in the system has a unique number. There are two lock states: “locked” and “unlocked”.

2. The security level of each lock and the unlocking authority of the user can be set on the host. The lock can be opened only when the user’s unlocking permission is greater than or equal to the security level of the lock and the lock is in the “locked” state.

3. The user’s fingerprint information, unlocking authority and lock security level are saved in the database on the host.

4. When unlocking, the user only needs to press the fingerprint collector. The fingerprint collector will send an interrupt event to the lock controller. The lock controller reads the user’s fingerprint from the fingerprint collector and sends the fingerprint information to the host. The host determines whether the user has unlocking authority according to the information stored in the database. If so, and the lock is currently in the “locked” state, the lock will be opened; Otherwise, the system will give an alarm.


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