21 Lecture

Q: Which type of message in a Sequence Diagram waits for a response before continuing? a) Synchronous message b) Asynchronous message c) Return message d) None of the above Solution: a) Synchronous message Q: What does an asynchronous message indicate in a Sequence Diagram? a) The message is sent to itself b) The message waits for a response c) The message proceeds without waiting for a response d) The message represents a loop Solution: c) The message proceeds without waiting for a response Q: Which message type indicates the response from the called object in a Sequence Diagram? a) Synchronous message b) Asynchronous message c) Return message d) None of the above Solution: c) Return message Q: In a Sequence Diagram, how are synchronous messages represented? a) With a dashed arrow b) With a solid arrow c) With a dashed line d) With a solid line Solution: d) With a solid line Q: What does a return message look like in a Sequence Diagram? a) A dashed line with an arrowhead b) A solid line with an arrowhead c) A dashed line without an arrowhead d) A solid line without an arrowhead Solution: a) A dashed line with an arrowhead Q: Which message type indicates a one-way communication without waiting for a response? a) Synchronous message b) Asynchronous message c) Return message d) Callback message Solution: b) Asynchronous message Q: How are messages representing loops depicted in a Sequence Diagram? a) With a solid line and an arrowhead b) With a dashed line and an arrowhead c) With a solid line and a loop arrow d) With a dashed line and a loop arrow Solution: d) With a dashed line and a loop arrow Q: What is the primary purpose of using message types in a Sequence Diagram? a) To indicate the object's name b) To represent the message content c) To show the direction of message flow d) To specify the message timing Solution: d) To specify the message timing Q: In a Sequence Diagram, how do you differentiate between synchronous and asynchronous messages? a) By the presence of an arrowhead b) By the presence of a loop arrow c) By the type of line used d) By the position of the object's name Solution: c) By the type of line used Q: What message type is used to indicate a method call from one object to another in a Sequence Diagram? a) Synchronous message b) Asynchronous message c) Return message d) Callback message Solution: a) Synchronous message

Q: What is the purpose of a Synchronous message in a Sequence Diagram? A: A Synchronous message indicates a method call where the sender waits for a response from the receiver before continuing. Q: How is an Asynchronous message different from a Synchronous message in a Sequence Diagram? A: An Asynchronous message represents a method call where the sender continues its execution without waiting for a response from the receiver. Q: What does a Return message indicate in a Sequence Diagram? A: A Return message shows the response from the called object to the calling object after a method call is completed. Q: How are Synchronous messages represented in a Sequence Diagram? A: Synchronous messages are depicted with a solid line connecting the lifelines of the objects involved in the communication. Q: Describe the appearance of an Asynchronous message in a Sequence Diagram. A: An Asynchronous message is represented with a dashed line connecting the lifelines of the objects involved in the communication. Q: When is a Return message used in a Sequence Diagram? A: A Return message is used to show the response from the called object to the calling object after a method call is finished. Q: What is the significance of the arrowhead in a Return message? A: The arrowhead in a Return message points back to the calling object, indicating the direction of the response. Q: How are loops represented in a Sequence Diagram? A: Loops are depicted using a dashed line with a loop arrow, indicating repetitive message exchanges between objects. Q: What information is conveyed by the timing of messages in a Sequence Diagram? A: The timing of messages in a Sequence Diagram shows the order and sequence of interactions between objects during runtime. Q: How do message types in a Sequence Diagram help in understanding object interactions? A: Message types specify the communication behavior, such as synchronous or asynchronous, providing insights into how objects interact and exchange messages in the system.