Deque iterator() method in Java - GeeksforGeeks

20 Jun, 2020
The iterator() method of Deque Interface returns an iterator over the elements in this deque in a proper sequence. The elements will be returned in order from first (head) to last (tail). The returned iterator is a “weakly consistent” iterator.
Syntax:
Iterator iterator()
Parameters: This method does not accepts any parameter.
Returns: This method returns an iterator over the elements in this deque in a proper sequence.
Below programs illustrate iterator() method of Deque:
Program 1: With the help of ArrayDeque.
// Java Program Demonstrate iterator()// method of Dequeimport java.util.*;  public class GFG {    public static void main(String[] args)        throws IllegalStateException    {          // create object of Deque        Deque<Integer> DQ            = new ArrayDeque<Integer>();          // Add numbers to end of Deque        DQ.add(7855642);        DQ.add(35658786);        DQ.add(5278367);        DQ.add(74381793);          // Call iterator() method of Deque        Iterator iteratorVals = DQ.iterator();          // Print elements of iterator        // created from Deque        System.out.println("The iterator values"                           + " of Deque are:");          // prints the elements using an iterator        while (iteratorVals.hasNext()) {            System.out.println(iteratorVals.next());        }    }}
The iterator values of Deque are:
7855642
35658786
5278367
74381793

Program 2: With the help of LinkedList.
// Java Program Demonstrate iterator()// method of Dequeimport java.util.*;  public class GFG {    public static void main(String[] args)        throws IllegalStateException    {          // create object of Deque        Deque<Integer> DQ            = new LinkedList<Integer>();          // Add numbers to end of Deque        DQ.add(7855642);        DQ.add(35658786);        DQ.add(5278367);        DQ.add(74381793);          // Call iterator() method of Deque        Iterator iteratorVals = DQ.iterator();          // Print elements of iterator        // created from Deque        System.out.println("The iterator values"                           + " of Deque are:");          // prints the elements using an iterator        while (iteratorVals.hasNext()) {            System.out.println(iteratorVals.next());        }    }}
The iterator values of Deque are:
7855642
35658786
5278367
74381793

Program 3: With the help of LinkedBlockingDeque.
// Java Program Demonstrate iterator()// method of Dequeimport java.util.*;import java.util.concurrent.LinkedBlockingDeque;  public class GFG {    public static void main(String[] args)        throws IllegalStateException    {          // create object of Deque        Deque<Integer> DQ            = new LinkedBlockingDeque<Integer>();          // Add numbers to end of Deque        DQ.add(7855642);        DQ.add(35658786);        DQ.add(5278367);        DQ.add(74381793);          // Call iterator() method of Deque        Iterator iteratorVals = DQ.iterator();          // Print elements of iterator        // created from Deque        System.out.println("The iterator values"                           + " of Deque are:");          // prints the elements using an iterator        while (iteratorVals.hasNext()) {            System.out.println(iteratorVals.next());        }    }}
The iterator values of Deque are:
7855642
35658786
5278367
74381793

Program 4: With the help of ConcurrentLinkedDeque.
// Java Program Demonstrate iterator()// method of Dequeimport java.util.*;import java.util.concurrent.ConcurrentLinkedDeque;  public class GFG {    public static void main(String[] args)        throws IllegalStateException    {          // create object of Deque        Deque<Integer> DQ            = new ConcurrentLinkedDeque<Integer>();          // Add numbers to end of Deque        DQ.add(7855642);        DQ.add(35658786);        DQ.add(5278367);        DQ.add(74381793);          // Call iterator() method of Deque        Iterator iteratorVals = DQ.iterator();          // Print elements of iterator        // created from Deque        System.out.println("The iterator values"                           + " of Deque are:");          // prints the elements using an iterator        while (iteratorVals.hasNext()) {            System.out.println(iteratorVals.next());        }    }}
The iterator values of Deque are:
7855642
35658786
5278367
74381793

Reference: https://docs.oracle.com/javase/8/docs/api/java/util/Deque.html#iterator–
KaashyapMSK
Java - util package
java-deque
Java-Functions
Java
Java
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