The addAll() method of ConcurrentLinkedQueue is used to inserts all the elements of the Collection, passed as parameter to this method, at the end of a ConcurrentLinkedQueue. The insertion of element is in same order as returned by the collections iterator.
Syntax:
public boolean addAll(Collection<? extends E> c)
Parameter: This method takes a parameter cwhich represent collection whose elements are needed to be appended at the end of this ConcurrentLinkedQueue.
Returns: This method returns true if at least one action of insertion is performed.
Exception: This method throw two different Exceptions:
- NullPointerException – if the passed collection or any of its elements are null.
- IllegalArgumentException – if the passed collection is this queue itself.
Below programs illustrate addAll() method of ConcurrentLinkedQueue:
Example 1: Trying to add a list of numbers to ConcurrentLinkedQueue.
// Java Program Demonstrate addAll() // method of ConcurrentLinkedQueue import java.util.concurrent.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// create an ConcurrentLinkedQueue
ConcurrentLinkedQueue<Integer>
queue = new ConcurrentLinkedQueue<Integer>();
// Add Numbers to queue
queue.add( 4353 );
// create a ArrayList of Numbers
ArrayList<Integer> arraylist = new ArrayList<Integer>();
// add some numbers to ArrayList
arraylist.add( 377139 );
arraylist.add( 624378 );
arraylist.add( 654793 );
arraylist.add( 764764 );
arraylist.add( 838494 );
arraylist.add( 632845 );
// Displaying the existing ConcurrentLinkedQueue
System.out.println( "ConcurrentLinkedQueue: " + queue);
// Displaying the existing Collection
System.out.println( "Collection to be added: " + arraylist);
// apply addAll() method and passed the arraylist as parameter
boolean response = queue.addAll(arraylist);
// Displaying the existing ConcurrentLinkedQueue
System.out.println( "Collection added: " + response);
// Displaying the existing ConcurrentLinkedQueue
System.out.println( "ConcurrentLinkedQueue: " + queue);
}
} |
ConcurrentLinkedQueue: [4353] Collection to be added: [377139, 624378, 654793, 764764, 838494, 632845] Collection added: true ConcurrentLinkedQueue: [4353, 377139, 624378, 654793, 764764, 838494, 632845]
Example 2: Trying to add a list of Strings to ConcurrentLinkedQueue.
// Java Program Demonstrate addAll() // method of ConcurrentLinkedQueue import java.util.concurrent.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// create an ConcurrentLinkedQueue
ConcurrentLinkedQueue<String>
queue = new ConcurrentLinkedQueue<String>();
// Add String to queue
queue.add( "Aman" );
queue.add( "Amar" );
// create a ArrayList of Numbers
ArrayList<String> arraylist = new ArrayList<String>();
// add some numbers to ArrayList
arraylist.add( "Sanjeet" );
arraylist.add( "Rabi" );
arraylist.add( "Debasis" );
arraylist.add( "Raunak" );
arraylist.add( "Mahesh" );
// Displaying the existing ConcurrentLinkedQueue
System.out.println( "ConcurrentLinkedQueue: " + queue);
// Displaying the existing Collection
System.out.println( "Collection to be added: " + arraylist);
// apply addAll() method and passed the arraylist as parameter
boolean response = queue.addAll(arraylist);
// Displaying the existing ConcurrentLinkedQueue
System.out.println( "Collection added: " + response);
// Displaying the existing ConcurrentLinkedQueue
System.out.println( "ConcurrentLinkedQueue: " + queue);
}
} |
ConcurrentLinkedQueue: [Aman, Amar] Collection to be added: [Sanjeet, Rabi, Debasis, Raunak, Mahesh] Collection added: true ConcurrentLinkedQueue: [Aman, Amar, Sanjeet, Rabi, Debasis, Raunak, Mahesh]
Example 3: Showing NullPointerException
// Java Program Demonstrate addAll() // method of ConcurrentLinkedQueue import java.util.concurrent.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// create an ConcurrentLinkedQueue
ConcurrentLinkedQueue<String>
queue = new ConcurrentLinkedQueue<String>();
// Add String to queue
queue.add( "Aman" );
queue.add( "Amar" );
// create a ArrayList which is equal to null
ArrayList<String> arraylist = null ;
// Displaying the existing ConcurrentLinkedQueue
System.out.println( "ConcurrentLinkedQueue: " + queue);
// Displaying the existing Collection
System.out.println( "Collection to be added: " + arraylist);
try {
// apply addAll() method and pass the arraylist as parameter
// since the arraylist is null, exception will be thrown
boolean response = queue.addAll(arraylist);
}
catch (NullPointerException e) {
System.out.println( "Exception thrown while adding null: " + e);
}
}
} |
ConcurrentLinkedQueue: [Aman, Amar] Collection to be added: null Exception thrown while adding null: java.lang.NullPointerException
Example 4: Showing IllegalArgumentException
// Java Program Demonstrate addAll() // method of ConcurrentLinkedQueue import java.util.concurrent.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// create an ConcurrentLinkedQueue
ConcurrentLinkedQueue<String>
queue = new ConcurrentLinkedQueue<String>();
// Add String to queue
queue.add( "Aman" );
queue.add( "Amar" );
// Displaying the existing ConcurrentLinkedQueue
System.out.println( "ConcurrentLinkedQueue: " + queue);
try {
// apply addAll() method and passed the queue as parameter
boolean response = queue.addAll(queue);
}
catch (IllegalArgumentException e) {
System.out.println( "Exception thrown while adding queue"
+ " to itself when collection is required: " + e);
}
}
} |
ConcurrentLinkedQueue: [Aman, Amar] Exception thrown while adding queue to itself when collection is required: java.lang.IllegalArgumentException