Java Archives - Page 2 of 4

BlockingDeque

BlockingDeque is an extended implementation of queue where we can enqueue or dequeue on both ends of the queue. All BlockingDeque implementions on array or linked queues are thread-safe implementations. Below is a simple usage of BlockingDeque

import java.util.Queue;
import java.util.concurrent.BlockingDeque;
import java.util.concurrent.LinkedBlockingDeque;

public class BlockingQueuesExamples {
	
	public static void main(String[] args) throws InterruptedException {
		
		BlockingDeque<String> linkedBlockingDeque = new LinkedBlockingDeque<String>();
		
		linkedBlockingDeque.offer("Apple");
		linkedBlockingDeque.offer("Orange");
		linkedBlockingDeque.offer("Peach");
		
		queueStatus(linkedBlockingDeque);
		
		linkedBlockingDeque.offerFirst("Banana");
		linkedBlockingDeque.offerFirst("Guava");
		
		queueStatus(linkedBlockingDeque);
		
		linkedBlockingDeque.offerLast("Pomegranate");
		linkedBlockingDeque.offerLast("Grape");
		
		linkedBlockingDeque.offer("Avacado");
		
		// Note: offerLast() and offer() method will do the same operation...
		queueStatus(linkedBlockingDeque);
		
		System.out.println("Dequeued at Head of Queue: " + linkedBlockingDeque.takeFirst());
		System.out.println("Dequeued at Tail of Queue: " + linkedBlockingDeque.takeLast());
		System.out.println("Dequeued at Head of Queue: " + linkedBlockingDeque.take()); 
		// Note: takeFirst() and take() method will do the same operation...
		
		queueStatus(linkedBlockingDeque);
		
	}

	
	
	public static void queueStatus(Queue linkedBlockingDeque) {
		System.out.println("---------------------------");
		System.out.println("Linked Blocking Deque Size:" + linkedBlockingDeque.size());
		System.out.println("Items:");
		System.out.println(linkedBlockingDeque);
		System.out.println("---------------------------");
	}
}

import java.util.Queue;

import java.util.concurrent.BlockingDeque;

import java.util.concurrent.LinkedBlockingDeque;

public class BlockingQueuesExamples {

public static void main(String[] args) throws InterruptedException {

BlockingDeque<String> linkedBlockingDeque = new LinkedBlockingDeque<String>();

linkedBlockingDeque.offer("Apple");

linkedBlockingDeque.offer("Orange");

linkedBlockingDeque.offer("Peach");

queueStatus(linkedBlockingDeque);

linkedBlockingDeque.offerFirst("Banana");

linkedBlockingDeque.offerFirst("Guava");

queueStatus(linkedBlockingDeque);

linkedBlockingDeque.offerLast("Pomegranate");

linkedBlockingDeque.offerLast("Grape");

linkedBlockingDeque.offer("Avacado");

// Note: offerLast() and offer() method will do the same operation...

queueStatus(linkedBlockingDeque);

System.out.println("Dequeued at Head of Queue: " + linkedBlockingDeque.takeFirst());

System.out.println("Dequeued at Tail of Queue: " + linkedBlockingDeque.takeLast());

System.out.println("Dequeued at Head of Queue: " + linkedBlockingDeque.take());

// Note: takeFirst() and take() method will do the same operation...

queueStatus(linkedBlockingDeque);

}

public static void queueStatus(Queue linkedBlockingDeque) {

System.out.println("---------------------------");

System.out.println("Linked Blocking Deque Size:" + linkedBlockingDeque.size());

System.out.println("Items:");

System.out.println(linkedBlockingDeque);

System.out.println("---------------------------");

}

Output:

---------------------------
Linked Blocking Deque Size:3
Items:
[Apple, Orange, Peach]
---------------------------
---------------------------
Linked Blocking Deque Size:5
Items:
[Guava, Banana, Apple, Orange, Peach]
---------------------------
---------------------------
Linked Blocking Deque Size:8
Items:
[Guava, Banana, Apple, Orange, Peach, Pomegranate, Grape, Avacado]
---------------------------
Dequeued at Head of Queue: Guava
Dequeued at Tail of Queue: Avacado
Dequeued at Head of Queue: Banana
---------------------------
Linked Blocking Deque Size:5
Items:
[Apple, Orange, Peach, Pomegranate, Grape]
---------------------------

---------------------------

Linked Blocking Deque Size:3

Items:

[Apple, Orange, Peach]

---------------------------

Linked Blocking Deque Size:5

Items:

[Guava, Banana, Apple, Orange, Peach]

---------------------------

Linked Blocking Deque Size:8

Items:

[Guava, Banana, Apple, Orange, Peach, Pomegranate, Grape, Avacado]

---------------------------

Dequeued at Head of Queue: Guava

Dequeued at Tail of Queue: Avacado

Dequeued at Head of Queue: Banana

---------------------------

Linked Blocking Deque Size:5

Items:

[Apple, Orange, Peach, Pomegranate, Grape]

---------------------------

Encoding/Decoding In Java

Encoding/Decoding is the method of representing an data, to a different format so that data can be transferred through the network or web. Encoder usually converts the data into web representation and after received in the other end, decoder converts back the web representation data to original data. 1. Base64 Encoding/Decoding Base64 is a way … Continue reading “Encoding/Decoding In Java”

Serialization

A Java Class Object needs to serialized if we need to store or transfer with the state values. For any IO operations or network operations usually the java class objects needs to sent/received via network via bytes. During serialization, Object along with state is serialized to bytes and can be processed between the systems as … Continue reading “Serialization”

Encryption-Decryption (AES)

Encryption is process of encoding meaningful information using mathematical algorithms using a standard key, so that only authorised parties can only decode/decrypt it. Authorised parties usually shares the secret keys each other so that encrypted information can only be decrypted by them. Plain Text + Key -> Encrypted text Encrypted Text – Key -> Plain … Continue reading “Encryption-Decryption (AES)”

Hashtable

Hashtable is an implementation for storing/processing list of objects using a hashkey and buckets. Hashtable has default load capacity of 11, where it will create default 11 buckets if not provided in specific., and stores the list of objects in the buckets based on the object hashkey. Any object/value inserted into Hashtable object, will be … Continue reading “Hashtable”

java.util.Map

Map is another important key interface in Java present in java.util package. Map contains list of objects associated with a key., for quick retrieval.Each Key is tied to one object i.e., every Object has its own unique key. Since Map stores object values based on keys, it dont maintain any order. Add/Retrieval/Search operations can be … Continue reading “java.util.Map”

java.util.Set

Set is another important Datastructure created in Java, just like List.Set is same as List, except it dont contain duplicates, and dont maintain order. As you remember, List can have duplicates & also maintains internal Order. Set Types: Below are the most used implementation classes of Set Interface. HashSet – HashTable implementation of Set Interface. … Continue reading “java.util.Set”

java.util.List

List is an interface, the most widely used data structure in java, implements the Collections interface. List stores a list of objects, in an inserted order, stores duplicate values. There are different data structure implementations of List interface, like ArrayList class, LinkedList class, Vector class etc., 1. Insert/Delete a Object in a List Methods : … Continue reading “java.util.List”

Threads (Runnable vs Thread)

1.What is Thread? A thread in Java is nothing but an instance of class which is running independently to complete its job.Thread is created in Java with the help of java.lang.Thread class, and hence it is controlled using the same class. Threads executes parallel without waiting for main program/each other and completes its job, unless … Continue reading “Threads (Runnable vs Thread)”

Collections

Collection is the core framework developed in Java using design Patterns.This framework provides the data structure architecture to store, retrieve and process the group of objects/elements. Java Collections has so many interfaces like List, Map, Set, Queue, Vector. List – Ordered collection of Objects, (Maintain Insertion Order) Map – Collection of Key Value Pair Objects, … Continue reading “Collections”