Java Data Structure Definition #2

Java Data Structure #2

So from the last article I already explain to you what is a Data Structure in general and what is a Java Data Structure. Just like I promised in that craftingez6-coding post, within this 2 post I’ll explain to you the Java Data Structure (interface and classes) one by one.

Enumeration

Enumeration is a type of Interface, enumeration itself is not actually a data structure, but it surely is very very important to the context of the other data structures. The enumeration interface means to retrieve a successive elements from a data structure.
In example,
Enumeration could define a method called nextElement. And that method is used to get the next element inside the data structure that contains more than 1 elements.
 

Bitset

BitSet is a type of class that implements a group of, guess what? “bits” or flags that you / the person can set and clear individually. This type of class is very useful in some cases where you need to keep up to code a set of Boolean values; you could just assign a bit to each value then set or clear it as appropriate

Vector

Vector class actually have similarities with a traditional Java array. Well except that Vector class can grow as necessary to accommodate new elements. 
 
Just like an array, the elements that is inside the Vector object can be accessed via index into the vector. You know what, the nice thing about Vector is that you doesn’t have to worry anymore about setting the elements into a specific size upon creation, it’ll actually grows and shrinks automatically when it is necessary.

The Stack

Stack class in java implements the last-in-first-out (LIFO) stack of elements. Imagine this illustration, you can imagine stack literally as a vertically stacked objects on top of each other. 
 
When you add new objects, it will get stacked on top of the others (the last object).
 
Then, when you pull an element off from that stacked objects. The last object will be the first object to come back off again.

The Dictionary

This dictionary doesn’t literally mean a dictionary, but it is rather an abstract class that defines data structure for mapping key to values. This kind class is useful whenever you want to access data via particular key rather than using an integer index.
Since the dictionary class is abstract, the class only provides the framework for a key mapped data. Rather than some specific implementation.

Data Structure Definition Java

What is Data Structure?

Data Structure in javaData Structure,

first of all lets break it down to pieces : Data and Structure.
What is a data? Googling on the internet said :

Philosophy “things that is probably known or assumed as facts, making the basis of reasoning or calculation”.
                    Computing “the quantities, characters, or symbols on which operations are performed by a computer, being stored and transmitted in the form of another electrical signals and recorded on magnetic, optical, or mechanical recording media

Continue reading Data Structure Definition Java

Java Modifiers Types Definition

Java Modifiers Types

So, folks.. first of all what goes through your mind when you hear “modify”, well for me when I hear that word the simplest meaning is to “change”. So what is a modifier, basically modifiers (In java) are a keywords that you can add to those definitions to change their meanings. In the java language there are a wide range of variety for java modifiers types, including the following modifiers :

  • Java Access Modifiers 
  • Java Non Access Modifiers

Continue reading Java Modifiers Types Definition

Multi Threading Programming (Java)

Multi Threading Programming In Java

What is the multi threading programming that we used is Java, hear this.. Java is actually a multi-threaded programming language and by that Java can let us develop a multi-threaded program.

Do you know what a multi-threaded program is? well a multi-threaded program contains two or more than two parts. Which runs concurrently and each of that one part can handle different task (i.e codes that contains methods, constructors etc) at the same equal time. This can actually improves the optimal use of the available resource, if you have multiple CPUs.

Basically multi threading programming takes the idea of multi tasking. Which is “doing more than 1 activities at the same time”. Multi tasking in our terms it means when a multiple processes share a common process resource such as a CPU.
Continue reading Multi Threading Programming (Java)

Code Aggregation *for code reusability

What is Code Aggregation

code aggregation
Code aggregation as reusability

If there is an entity reference in a class, then you what you have is a code aggregation. Aggregation usually represents HAS-A relationship.
Consider the following situation situation.

A Worker object contains many informations such as id, name, phone number etc. It contains one more object named address, which contains its own informations such as city, state, country etc. see it as given below.

Continue reading Code Aggregation *for code reusability

Java JSpinner & Its Definition

What is Java JSpinner

Okay lads, today we’re talking about Spinner. But hey! it’s not a fidget spinner that we’re talking. Because It is a Java JSpinner and JSpinner allows the users to select a number or an object value from an already sequence using single line input.

The Syntax :
public class JSpinner extends JComponent implements Accessible  

First of all here are common constructor of Java JSpinner:

  • JSpinner() : This class is used to construct a spinner with an Integer SpinnerNumberModel and in addition of an initial value of 0 and with no minimum or maximum limits.
  • JSpinner(SpinnerModel model) : This is another one of Java JSpinner that is used to construct a spinner for a given model.
Especially relevant here are common methods ofmJava JSpinner :

 

  • void addChangeListener(ChangeListener listener) : This method is used to add another listener to the list which will be notified each time a change to the model occurs.
  • Object getValue() :While this method is used to return the current value of the model.
Finally It’s Exmpl time! :
 
import javax.swing.*;    
public class SpinnerExample {  
    public static void main(String[] args) {    
    JFrame f=new JFrame(“Not Fidget Spinner”);    
    SpinnerModel value =  
             new SpinnerNumberModel(10, //initial value  
                0, //minimum value  
                20, //maximum value  
                2); //step  
    JSpinner spinner = new JSpinner(value);   
            spinner.setBounds(100,100,50,30);    
            f.add(spinner);    
            f.setSize(300,300);    
            f.setLayout(null);    
            f.setVisible(true);     
}  
}  
 
And This will output :

Java strictfp Keyword

strictfp may sound odd to you, because at first I do as well. But strictfp is a java keyword that will ensure your result will and always be the same on every platform if you do an operation in the floating point variable. The result of an operation in the floating point variable may differ to each and every platform you use, and by that java programming language provide the strictfp so you’ll get the same result on every platform. Also by having strictfp you have more control over floating point arithmetic.

Usable strictfp keyword syntax

The strictfp can be used methods, classes and interfaces.
class Example{
strictfp void Example(){ //strictfp applied on methods
  }
}

strictfp Example{ //strictfp applied on classes
}

strictfp interface Example{ //strictfp applied on interface
}

Unusable strictfp keyword syntax

The strictfp can not be used in abstract method, variables or constructors.
class Example{
strictfp int value = 10; //can not be used in variables i.e integer
}

class Example{
strictfp abstract void example(); //can not be used in abstract methods
}

class Example{
strictfp Example(){} // can not be used in constructors
}

Java Covariant Return Type

Howdy Mowdy People? Have you ever override a method by changing its return type? Well for y’all that is already a pro in Coding may know this type of overriding, but for those who is still  a green horn in coding, just like me :’D maybe. This kind of method overriding is called Java Covariant Return Type, which is not available until Java5 came out.

Here ok, let me just show you a simple presentation of this Covariant Type :

public class A{  
A get(){return this;}  
}  
  
class B extends A{  
B get(){return this;}  
void message(){System.out.println(“Craftingez6 covariant return type“);}  
  
public static void main(String args[]){  
new B().get().message();  
}  
}  

This will output :

Craftingez6 covariant return type

Well as you can see, the return type of get() method A class is A, but then… the return type of B class is.. B. Both of this class have a different return type but both of them is tied in a method overriding, B overriding A.This thing/process/phenomenon is called Covariant return type.

There we go I’ve explaing it. See you!

Conclusions

  • Method overriding is called Java Covariant Return Type
  • Both of this class have a different return type but both of them is tied in a method overriding, B overriding A

How To Play MP3 Files in Java Eclipse

How is it going coders? for today Tutor… I’m gonna tell y’all how to Play MP3 files in Java Program. Just like always for todays example I’m using Eclipse, you could use it or any other IDE that suites you. For todays program I’m using MP3 files, so thats not too hard to find.

 First of all you need to have your MP3 files inside your source folder like this :

Just look at that “Mfg” MP3 files that I have inside my source folder for “MainMP3” Program.
Now for the coding Spices :


Wait!!! Before all of that You need to Download JLayer Here :  JLayer
And add it to your program Build Path using “Add External JARs” :

//1st now well import the important classes
//(notice that there is a class/package named javazoom.jl…)

import java.io.FileInputStream;
import java.io.FileNotFoundException;

import javazoom.jl.decoder.JavaLayerException;
import javazoom.jl.player.Player;

//2nd we create our method inside our class
public class MainMP2 {
 

//here we create the main method

    public static void main(String[] args){
       
        try{
        FileInputStream fileInputStream = new FileInputStream(“Mfg.mp3”);
 //here we find our sound file
        Player player = new Player(fileInputStream);
        player.play();
        System.out.println(“Song is Playing”);
        } catch(FileNotFoundException e){
            e.printStackTrace();
        }catch(JavaLayerException e){
            e.printStackTrace();
        }
       
    }
   
}

Well since I can’t tell you how it sounds in here, you can go and check my Youtube Channel for the Voice explanation : MP3 Files in Java Eclipse Check it out!! and subscribe