Enumset in Java

Enum set are the implementation of a set interface, and it extends Abstract class in java for enumeration type. The are Set collection provides the functionality to work with enums in java. Enum sets are not synchronized; hence they provide faster accessing of elements. Enum sets do not allow adding null elements; if we try to add a null value, it will throw a null pointer exception.

Syntax:

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public abstract class EnumSet<e extends enum>> || This is the class decralation of enum set.
EnumSet<e extends enum>> enum1, enum2, enum3, enum4; || Declare different enum.</e></e>

As enum sets are not synchronized, they are much master, but we can synchronise them by using collections class synchronized method() below find the syntax for synchronized.

Collections.synchronizedSet(java.util.Set<t>)
Set<enum_type> s = Collections.synchronizedSet(EnumSet.noneOf(EnumClass.class));</enum_type></t>

Methods of Enumset in Java

• static > allOf(Class elementType): This method is used to create the enum with all elements mentioned.
• EnumSet clone(): This method is used to create the copy of the set. Return type is EnumSet.
• static > complementOf(EnumSet s): This method is used to create the enum set specified in the method , this enum will contain all the elements which are not contained in set.
• static > copyOf(Collection c): This will create a copy of enum set which is specified in the method. But it takes the collection parameter.
• static > copyOf(EnumSet s): This will create a enum, specified as enum set. This will return an EnumSet.
• static > noneOf(Class elementType): This will also create an enum which specified in the method. Return an EnumSet.
• static > of(E e): Also create an enum with initially elements. Return type is EnumSet.
• static > of(E first, E… rest): Creates enum containing elements and it returns EnumSet
• static > of(E e1, E e2): This method will create an enum with mentioned elements. Return type is EnumSet
• static > of(E e1, E e2, E e3): This method will create an enum. Method return type is EnumSet .
• static > of(E e1, E e2, E e3, E e4): This methods will also create the enum with specified elements. Return type is EnumSet
• static > of(E e1, E e2, E e3, E e4, E e5): This method is also create the enum with specifies elements passed as enum. Return type is EnumSet
• static > range(E from, E to): In this method we can specified the range. Then it will create a new enum. Return type is EnumSet .

Note:

• Enum set implements various class and interface. Enum set class declaration :
• public abstract class EnumSet> extends AbstractSet implements Cloneable, Serializable

Interfaces which are implemented by enum set:

• Cloneable
• Set
• Serializable
• Collection
• Iterable

Classes that are extending by enum set are the following:

• AbstractSet

Examples of Enumset in Java

Following are the example of enumset are given below:

Example #1

In the below example, w are adding elements to the enum set.

Code:

import java.util.EnumSet;
public class EnumsetDemo {
public static void main(String[] args) {
// creating reference
EnumSet<enumdemo> enum1;
// here we are adding elements to the enum1 which we create above.
enum1 = EnumSet.of(EnumDemo.JAVA, EnumDemo.JAVASCRIPT,
EnumDemo.C, EnumDemo.PHP, EnumDemo.GO, EnumDemo.PYTHON, EnumDemo.TYPESCRIPT);
System.out.println("Enum set 1 containing values are :: ");
System.out.println( enum1);
}
}
enum EnumDemo
{
JAVA, PYTHON, PHP, C, GO, JAVASCRIPT, TYPESCRIPT
};</enumdemo>

Output:

Example #2

In this example, we are creating enum2 by using the value sf enum1 only. Below find an example.

Code:

import java.util.EnumSet;
public class EnumsetDemo {
public static void main(String[] args) {
// creating reference
EnumSet<enumdemo> enum1;
// here we are adding elements to the enum1 which we create above.
enum1 = EnumSet.of(EnumDemo.JAVA, EnumDemo.JAVASCRIPT,
EnumDemo.C, EnumDemo.PHP, EnumDemo.GO, EnumDemo.PYTHON, EnumDemo.TYPESCRIPT);
System.out.println("Enum set 1 containing values are :: ");
System.out.println( enum1);
// adding value to another enum set using addAll method
EnumSet<enumdemo> enum2 = EnumSet.allOf(EnumDemo.class);
System.out.println("Enum set 2 containing values are :: ");
System.out.println( enum2);
}
}
enum EnumDemo
{
JAVA, PYTHON, PHP, C, GO, JAVASCRIPT, TYPESCRIPT
};</enumdemo></enumdemo>

Output:

Example #3

In this example, we are finding complements f enum1 to enum2.

Code:

import java.util.EnumSet;
public class EnumsetDemo {
public static void main(String[] args) {
// creating reference
EnumSet<enumdemo> enum1;
// here we are adding elements to the enum1 which we create above.
enum1 = EnumSet.of(EnumDemo.JAVA, EnumDemo.JAVASCRIPT,
EnumDemo.C, EnumDemo.PHP, EnumDemo.GO, EnumDemo.PYTHON, EnumDemo.TYPESCRIPT);
System.out.println("Enum set 1 containing values are :: ");
System.out.println( enum1);
// finind completents of enum1 to enum2
EnumSet<enumdemo> enum2 = EnumSet.complementOf(enum1);
System.out.println("Enum set 2 containing values are :: ");
System.out.println( enum2);
}
}
enum EnumDemo
{
JAVA, PYTHON, PHP, C, GO, JAVASCRIPT, TYPESCRIPT
};</enumdemo></enumdemo>

Output:

Example #4

Specifying range to elements to be copied.

Code:

import java.util.EnumSet;
public class EnumsetDemo {
public static void main(String[] args) {
// creating reference
EnumSet<enumdemo> enum1;
// here we are adding elements to the enum1 which we create above.
enum1 = EnumSet.of(EnumDemo.JAVA, EnumDemo.JAVASCRIPT,
EnumDemo.C, EnumDemo.PHP, EnumDemo.GO, EnumDemo.PYTHON, EnumDemo.TYPESCRIPT);
System.out.println("Enum set 1 containing values are :: ");
System.out.println( enum1);
// here we are specifing the range to another enum using enum1
EnumSet<enumdemo> enum2 = EnumSet.range(EnumDemo.PYTHON, EnumDemo.JAVASCRIPT);
System.out.println("Enum set 2 containing values are :: ");
System.out.println( enum2);
}
}
enum EnumDemo
{
JAVA, PYTHON, PHP, C, GO, JAVASCRIPT, TYPESCRIPT
};</enumdemo></enumdemo>

Output:

Example #5

Making copy from existing enum.

Code:

import java.util.EnumSet;
public class EnumsetDemo {
public static void main(String[] args) {
// creating reference
EnumSet<enumdemo> enum1;
// here we are adding elements to the enum1 which we create above.
enum1 = EnumSet.of(EnumDemo.JAVA, EnumDemo.JAVASCRIPT,
EnumDemo.C, EnumDemo.PHP, EnumDemo.GO, EnumDemo.PYTHON, EnumDemo.TYPESCRIPT);
System.out.println("Enum set 1 containing values are :: ");
System.out.println( enum1);
// here we are copying elements of enum1 to enum2.
EnumSet<enumdemo> enum2 = EnumSet.copyOf(enum1);
System.out.println("Enum set 2 containing values are :: ");
System.out.println( enum2);
}
}
enum EnumDemo
{
JAVA, PYTHON, PHP, C, GO, JAVASCRIPT, TYPESCRIPT
};</enumdemo></enumdemo>

Output:

Conclusion

Java EnumSet is the implementation of the SET interface in java. They are a special type of java collection framework that provides support for enum types in java. We can also make them synchronized as these are not synchronized.

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