How to Convert String to enum in Java?

In this article, we shall gain the complete knowledge about how to convert the string to enum in Java. The complete process that happens in the approach shall be discussed and each and every method shall also be discussed.

String

Strings are collections of characters that are frequently used in Java programming. Objects in the programming language Java include strings.

For creating and manipulating strings, the Java platform offers the String class.

Now let us acknowledge about the Enum in java.

Enum

A data type in Java called Enum has a predetermined set of constants.

Java Enums can be compared to classes that contain a predetermined collection of constants (a variable that does not change). Implicitly, the Java enumeration constants always static and final. It has been accessible since JDK 1.5.

Enums are employed to design custom data types, much like classes. In Java, an Enum is defined using the Enum data type, also referred to as the Enumerated Data Type. Enumeration of Java is much more powerful than it is in C/C++. Here, we have the option of defining an Enum either within or outside of the class.

Now let us go through how the conversion process occurs.

Approach

With the help of the Enum.valueOf() method, you may generate Enum from a String. ValueOf(), along with the methods values(), name(), and cardinal(), is a static method that is automatically added to every Enum class during compilation. If String is not the same as the specified Enum, the code will throw the error "java.lang.IllegalArgumentException: No enum const class." The same method can be applied to turn a string into an Enum instance.

String constants have been supported in switch cases in Java since version 7, although Enum is usually recommended across both Integer and Character constants since it offers type safety.

In the context of String nor Integer, the compiled code will check if a variable is of the appropriate version but it can't access values, thus you should choose Enum to specify a very well-fixed number of items. The compiler will verify that an invalid value is not supplied.

Here is a Java code sample for converting a String to an Enum. It exemplifies both methods for generating Enums in Java from Strings that we've covered thus far. Any String can be converted to its corresponding Enum using the same method. To prevent Java's IllegalArgumentException, always be sure to give the right String.

Another way to convert a string to an enum is to use the values() method to iterate through all of the specified enum instances, then use equals to compare the provided string to each one (). Despite the fact that it works well, the approach uses more code than Enum.valueOf ().

Example

Let us create an enum with name Vehicles with 5 constants representing models of 5 different scoters with their prices as values, as shown below -

enum Vehicles {
   // variables with values
   ACTIVA125(80000), ACTIVA5G(70000), ACCESS125(75000), VESPA(90000), TVSJUPITER(75000); //Instance variable
   private int price;
   //Constructor to set the instance variable's value
   Vehicles(int price) {
      this.price = price;
   }
   // Static method to display the price
   public int getPrice(){
      return this.price;
   }
}

The Java program below takes a String value out from users, uses the method to turn into an Enum constants of type Vehicles, and then displays the amount (price) of the chosen constant.

File name: Enumeration.java

public class Enumeration {
   public static void main(String args[]) {
      Scanner sc = new Scanner(System.in);
      System.out.println("Available scoters: [activa125, activa5g, access125, vespa, tvsjupiter]");
      System.out.println("Enter the name of required scoter: ");
      String name = sc.next();
      Vehicles v = Vehicles.valueOf(name.toUpperCase());
      System.out.println("Price: "+v.getPrice());
   }
}

Output

Available scoters: [activa125, activa5g, access125, vespa, tvsjupiter]
Enter the name of required scoter:
activa125
Price: 80000

For each method call thus far, we have iterated over through the constant values. We have additional possibilities for comparison thanks to iteration. For instance, we can disregard case and compare the provided value to the name property.

Conclusion

That concludes the section on creating Enums in Java from Strings. Java programmers must be aware with this method to quickly convert String into Enum since it is a fairly common requirement. In conclusion, choose Enum above String to achieve compile-time verification and type safety, but keep in mind that String is a generic type and that you can save your information in the database as String, which will then all be transformed to Enum at runtime.