Understanding object-oriented methodologies is often difficult. You already understand that object-oriented analysis and design emulates the way human beings tend to think and conceptualize problems.
As an example, consider a typical house in which there are several bedrooms, a kitchen, and a laundry room—each with a distinct function. You sleep in the bedroom, you wash clothes in the laundry room, and you cook in the kitchen. Each room encapsulates all the items needed to complete necessary tasks.
You do not have an oven in the laundry room or a washing machine in the kitchen. However, when you do the laundry, you do not just add clothes to the washer and wait in the laundry room; once the machine has started, you may go into the kitchen and start cooking dinner. How do you know when to go back to check the laundry? When the washer buzzer sounds, a message is sent to alert you to go back into the laundry room to put in a new load. While you are folding clothes in the laundry room, the oven timer may ring to inform you that your dinner is done cooking.
What you have is a set of well-defined components: Each provides a single service to communicate with the other components using simple messages when something needs to be done. If you consider a kitchen, you see it is composed of several, smaller components, including the oven, refrigerator, and microwave. Top-level objects are composed of smaller components that do the actual work. This perspective is a very natural way of looking at the world, and one with which everyone is familiar. The same thing is done in object-oriented programming:
• Identify components that perform a distinct service.
• Encapsulate all items in the component necessary to get the job done.
• Identify the messages that need to be provided to the other components.
Although the details can be quite complex, they are the basic principles of object-oriented programming.
Consider the microwave oven in your kitchen, using the object-oriented thinking described above.
Create a table with the following four column headings: Top-Level Objects, Communicates With, Incoming Messages, and Outgoing Messages.
• Identity the top-level objects of the microwave.
• Explain some graphical user interfaces and communication messages that occur during the operation of a microwave.
Describe some of the advantages of having a componentized system. For example, what happens if the microwave breaks?
Post your completed CheckPoint as an attachment.
To identify the top-level objects of the microwave, we need to consider the different components that make up the microwave and perform a distinct service. Let's begin by listing the top-level objects:
Top-Level Objects:
1. Microwave Control Panel
2. Microwave Cavity
3. Microwave Display
Next, let's identify the communication between these top-level objects:
Communicates With:
1. Microwave Control Panel communicates with Microwave Cavity and Microwave Display
2. Microwave Cavity communicates with Microwave Control Panel
3. Microwave Display communicates with Microwave Control Panel
Now, let's determine the incoming and outgoing messages for each communication:
Incoming Messages:
1. Microwave Control Panel receives user input for setting time, power level, etc.
2. Microwave Cavity receives instructions from the Microwave Control Panel to start/stop heating.
Outgoing Messages:
1. Microwave Control Panel sends commands to the Microwave Cavity to start/stop heating.
2. Microwave Control Panel sends display updates to the Microwave Display.
Graphical user interfaces and communication messages during the operation of a microwave can include:
1. Display Updates: The Microwave Control Panel sends messages to the Microwave Display to update the current status, time, power level, etc. For example, when the user sets a cooking time, the display will show the countdown as the microwave operates.
2. User Input: The Microwave Control Panel receives user input through various buttons and knobs to set cooking time, power level, start/stop the microwave, etc. This interaction allows the user to control the microwave's functions.
3. Heating Instructions: The Microwave Control Panel sends messages to the Microwave Cavity instructing it to start heating according to the user's input. These messages contain information such as the selected power level, cooking time, and any specific instructions for different cooking modes.
Having a componentized system, like the one described above, offers several advantages:
1. Modularity: Each component performs a distinct service, making it easier to understand and manage the system. This modularity allows for easier maintenance, updates, and enhancements to specific components without affecting others.
2. Reusability: Components can be reused in other systems, promoting code efficiency and reducing development time. For example, the Microwave Control Panel UI design principles and communication patterns can be reused in other appliances or software applications.
3. Encapsulation: The encapsulation of functionality within each component allows for data privacy and abstraction. Components can hide their internal implementation details while providing a defined interface for communication, promoting data integrity and security.
4. Flexibility: With a componentized system, it becomes easier to replace or upgrade individual components without affecting the entire system. For instance, if the microwave control panel malfunctions, it can be replaced or repaired independently, minimizing downtime and cost.
5. Scalability: The system can be scaled by adding or removing components as needed. For example, additional features like a convection oven could be added as a separate component without disrupting the existing functionalities.
In conclusion, applying object-oriented thinking to systems like a microwave helps in identifying well-defined components and their communication patterns. This approach provides benefits such as modularity, reusability, encapsulation, flexibility, and scalability to the system.