The compareAndSet() method of a AtomicReferenceArray class is used to atomically sets the value of index i of AtomicReferenceArray to newValue, if the current value at index i of AtomicReferenceArray object is equal to the expectedValue.This method will return true if update is successful.
Syntax:
public final boolean compareAndSet( int i, E expectedValue, E newValue)
Parameters: This method accepts:
- i which is an index of AtomicReferenceArray to perform the operation,
- expectedValue which is the expected value and
- newValue which is the new value to set.
Return value: This method returns true if successful and false return indicates that the actual value was not equal to the expected value.
Below programs illustrate the compareAndSet() method:
Program 1:
// Java program to demonstrate // compareAndSet() method import java.util.concurrent.atomic.*;
public class GFG {
public static void main(String[] args)
{
// create an atomic reference object.
AtomicReferenceArray<Integer> ref
= new AtomicReferenceArray<Integer>( 3 );
// set some value
ref.set( 0 , 1234 );
ref.set( 1 , 4322 );
// apply compareAndSet()
boolean op1
= ref.compareAndSet( 0 , 5434 , 8913 );
boolean op2
= ref.compareAndSet( 1 , 3236 , 6543 );
// print
System.out.println( "Operation at index 0: "
+ op1);
System.out.println( "Operation at index 0: "
+ op2);
}
} |
Output:
Operation at index 0: false Operation at index 0: false
Program 2:
// Java program to demonstrate // compareAndSet() method import java.util.concurrent.atomic.*;
public class GFG {
public static void main(String[] args)
{
// create an atomic reference object.
AtomicReferenceArray<String> ref
= new AtomicReferenceArray<String>( 3 );
// set some value
ref.set( 0 , "GFG" );
ref.set( 1 , "JS" );
// apply compareAndSet()
boolean op1
= ref.compareAndSet(
0 , "GFG" ,
"GEEKS FOR GEEKS" );
boolean op2
= ref.compareAndSet(
1 , "JS" ,
"JAVA SCRIPT" );
// print
System.out.println( "Operation at index 0: "
+ op1);
System.out.println( "New value at index 0: "
+ ref.get( 0 ));
System.out.println( "Operation at index 1: "
+ op2);
System.out.println( "New value at index 1: "
+ ref.get( 1 ));
}
} |
Output:
Operation at index 0: true New value at index 0: GEEKS FOR GEEKS Operation at index 1: true New value at index 1: JAVA SCRIPT