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Java Collections - ArrayBlockingQueue.element() Examples

Java Collections Java Java API 

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Class:

java.util.concurrent.ArrayBlockingQueue

java.lang.Objectjava.lang.Objectjava.util.AbstractCollectionjava.util.AbstractCollectionjava.util.CollectionCollectionjava.util.AbstractQueuejava.util.AbstractQueuejava.util.QueueQueuejava.util.concurrent.ArrayBlockingQueuejava.util.concurrent.ArrayBlockingQueuejava.util.concurrent.BlockingQueueBlockingQueuejava.io.SerializableSerializableLogicBig

Method:

E element()

Retrieves, but does not remove, the head of this queue. This method differs from peek() only in that it throws an exception if this queue is empty.


Examples


package com.logicbig.example.arrayblockingqueue;

import java.util.Arrays;
import java.util.concurrent.ArrayBlockingQueue;

public class ElementExample {

    public static void main(String... args) {
        ArrayBlockingQueue<Integer> q = new ArrayBlockingQueue<>(3, true,
                Arrays.asList(1, 2, 3));
        System.out.println("queue: " + q);
        Integer element = q.element();
        System.out.println(element);
        Integer element2 = q.element();
        System.out.println(element2);
    }
}

Output

queue: [1, 2, 3]
1
1




In case if the queue is empty:

package com.logicbig.example.arrayblockingqueue;

import java.util.concurrent.ArrayBlockingQueue;

public class ElementExample2 {

    public static void main(String... args) {
        ArrayBlockingQueue<Integer> q = new ArrayBlockingQueue<>(3);
        System.out.println("queue: " + q);
        Integer element = q.element();

    }
}

Output

Caused by: java.util.NoSuchElementException
	at java.base/java.util.AbstractQueue.element(AbstractQueue.java:136)
	at com.logicbig.example.arrayblockingqueue.ElementExample2.main(ElementExample2.java:16)
	... 6 more

See Also