PafZoo

This is a simple Java console project(Maven) for developer test assignment of PAF.

Usage

build

mvn clean package

After build, a jar file --PafZoo-1.0-SNAPSHOT-jar-with-dependencies.jar will be generated under target folder.

start

java -cp target/PafZoo-1.0-SNAPSHOT-jar-with-dependencies.jar com.paf.zoo.Main

After the program starts, a usage instruction will be shown by default. The program supports 4 types of command: display, live, help and exit.

-------------- Help/Usage ---------------
Commands in the zoo system:
display		Show current status of all animals in zoo
live		Live one day in zoo, all changes in zoo will be displayed
help		Show help information of command usage
exit		Exit system

Design

The following picture is the classes diagram of my application. The application design is aiming for expandability and maintainability. If Spring framework is allow to use, a better version could be designed.

There are 4 main layers main, command, service and model. Each layer only has interactions with its neighbor layers.

• The main layer is only consist of the Main class. It accepts user input from the console. By default, the application executes HELP command to show usage/help information to users. Main class doesn't need to know what commands are supported and how they are implemented.
• The command layer defines all the commands supported by the application. Each command might call specific service to execute the command.
• All the business logic is implemented in service layer. Such as how a zoo is initialized, what happens living one day in the zoo? There is a class DatabaseDataService defined in service layer. Implement it if you want save your data into a database instead of having it in memory.
• Model layer contains all the definitions of DTO(data transfer object). As the property optionality is not clear to me. In my program, name and favoriteFood are obligatory, other properties are optional. I only implemented the builder pattern on models: Chicken, Parrot and their parent class Bird.

Important aspects

1. Friendship actions(build/break) of different animals should occur in parallel;
2. Command design pattern makes the program extendable;
3. If A and B are already friends, they couldn't establish friendship again;
4. Animal couldn't build friendship with itself;

Questions

• If package Mockito is allowed to use, some unit tests of Command implementation could be added
• Could two animals have the same name? I assume Yes, two animals with with exactly the same properties shouldn't be equal. In the program, there a UUID property to identify Animal.
• Which properties of animal are required, which properties are optional? In my program, name and favoriteFood are obligatory， other properties are optional.