The enum keyword in Java is used to create a special type of class that can only contain a finite set of values. These values are called enum constants, and they are declared using the keyword enum
followed by the name of the enum class. For example, the following code creates an enum calledColor
with the three values RED
, GREEN
, and BLUE
:
public enum Color {
RED,
GREEN,
BLUE;
}
Enum constants are public, static, and final by default. This means that they can be accessed from anywhere in the program, and they cannot be changed. Enum constants can also be used with the switch keyword. For example, the following code uses a switch statement to print out the name of the colour that is passed in as a parameter:
public class ColorDemo {
public static void main(String[] args) {
Color color = Color.RED;
switch (color) {
case RED:
System.out.println("Red");
break;
case GREEN:
System.out.println("Green");
break;
case BLUE:
System.out.println("Blue");
break;
}
}
}
This code will print out the following output:
Red
A switch keyword is a powerful tool that can be used to execute different codes based on the value of a variable. When used with enum constants, it can be a very concise way to write code that checks for a specific value.
Here are some of the benefits of using enums in Java:
- Enum constants are public, static, and final by default, which makes them more secure and reliable.
- Enum constants can be used with the switch keyword, which makes it easy to write code that checks for a specific value.
- Enum constants can be used to represent a set of related values, such as the days of the week or the colours of the rainbow.
Here are some of the drawbacks of using enums in Java:
- Enum constants cannot be changed, which can make it difficult to update code if the values of the enum constants change.
- Enum constants can only be used with the switch keyword, which can limit the flexibility of the code.
Overall, enums are a powerful tool that can be used to represent a set of related values in Java. They offer a number of benefits, such as security, reliability, and conciseness. However, there are also some drawbacks, such as the inability to change the values of enum constants and the limited flexibility of the switch keyword.