Agile Methodology with SCRUM Framework Basics

Software development activities can be managed and taken care with different life cycle models. These life cycle models has became legacy since few years. Few of the available Software Development Life Cycle Models in short SDLC are Win-Win Model and Waterfall Model etc.

These traditional models has different phases of development. 

       1. Requirements 

       2. Analysis 

       3. Design 

       4. Implementation 

       5. Test 

       6. Documentation 

and 7. Maintenance 

In SDLC, the above stages are freezed one after the other. If developer is in Design phase and realized that there could be a possibility of change in requirements, then it is not possible to go back one phase and fix in Requirement phase. 
These scenarios and use cases has brought Agility in to existence in software development activities.  

Agility in English: 

Agility means "able to move quickly and easily".  Being agile in software development makes the development move or progressed quick enough and flexible to go back and forth through out the development phases and complete the activities on time.

Agile Methodology:

"Agility is the ability that gives better productivity..."

Agile is the ability to create and respond to change. It is a way of dealing with and ultimately succesing in an uncertain environment. Agile methodology has different subsets also called as frameworks. 
SCRUM and Kanban are few among others. These frameworks can be adapted as process solutions based upon different development needs.

SCRUM Framework:

Scrum is a process framework used to manage product development and other knowledge work.

SCRUM framework manages the development activities biweekly, 3 weeks or 4 weeks. This duration is called as Sprint. Usually it is not recommended to have more than 6 members or developers in a team.

Sprint:

Sprint is a duration of time where few backlogs are realized as tasks and completed by development team. Once the Sprint is completed these software changesets goes into release version of the application software.
Based on the need Sprint duration can be 2 or 3 or 4 weeks. But most of the Scrum experts suggest Biweekly sprints.

SCRUM and Meetings:

    1. Standup call

    2. Review Meeting

    3. Grooming Session

    4. Retrospective

Standup calls are held everyday morning that lasts for 15 minutes. And following are discussed:

    1. What is done yesterday?

    2. What is planned today?

    3. Any Roadblocks?

NOTE: It is not recommended to consider more than 15 minutes for Standup meeting

Review Meeting is held at the end of the Sprint showing different works and demos of Sprint's development activites.

Grooming Session lasts for one and half hours. During this session tasks are pulled from backlogs and discussed the following:

    1. Estimations for the Tasks

    2. Deciding the priorities

    3. Severity levels

    4. Assignments

Retrospective meetings are held after the end of Sprint and discussed about:

    What went correct..?

    What went wrong..?

And Appreciations if any...

     

Scrum framework and few notable points:

1. All requirements are consolidated as backlogs along with its descriptions and other details.
2. Estimations of backlogs are done with the Poker Cards
3. Poker cards are numbered in a Fibonacci order
4. SCRUM is managed by Certified SCRUM Master or SCRUM Coach
5. If Standups are not held with in 15 minutes, can be considered as limitation.
6. Virtual Boards are considered over Physical boards, if members are in remote locations 

SCRUM and Agile Supporting Tools:

1. Microsoft Azure Boards
2. Atlassian JIRA
3. IBM - Rational Team Concert 

SCRUM Limitations:

• Geographically if team members are located in different places, Agile may not be effective

Java API support for Exception Handling

First of all, please read below blog post to understand basics of Exception Handling in java.

Exception handling and java keywords

To continue from there, Basically Java default API has hierarchy of  java classes to support different uses cases of exceptions. 

The parent class of all Exceptions and Errors is Throwable. Please check below pictorial representation of  API Hierarchy.

Exception:

The class Exception and any subclasses that are also not subclasses of RuntimeException are checked exceptions.

And all subclasses of RuntimeException and RuntimeException class itself are Unchecked exception. Rest all are Checked exceptions

Examples of Unchecked Exceptions: 

         ArrayIndexOutOfBoundException

         NullPointerException

Error:

An Error is a subclass of Throwable that indicates serious problems that a reasonable application should not try to catch. Most such errors are abnormal conditions.

Examples: The ThreadDeath error

Java - Swing custom components - Rounded JButton

Unlike AWT, Java Swing tool kit provides feasibilty to create custom components and containers.

To understand Java GUI toolkits more clearly, please read my other articles on Swing and AWT. 

In this article I focus more on building custom components.

Let us see how to create simple Rounded JButton. The below program demonstrates How rounded JButton can be created and added to a JFrame.

 

Program:

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.GridLayout;
import java.awt.Shape;
import java.awt.geom.Ellipse2D;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class RoundedJButton extends JButton {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	public RoundedJButton(String title) {
		super(title);
		Dimension size = getPreferredSize();
		size.width = size.height = Math.max(size.width, size.height);
		setPreferredSize(size);

		setContentAreaFilled(false);
	}

	@Override
	protected void paintComponent(Graphics g) {
		if (getModel().isArmed()) {
			g.setColor(Color.lightGray);
		} else {
			g.setColor(getBackground());
		}
		g.fillOval(0, 0, getSize().width - 1, getSize().height - 1);

		super.paintComponent(g);
	}

	@Override
	protected void paintBorder(Graphics g) {
		g.setColor(getForeground());
		g.drawOval(0, 0, getSize().width - 1, getSize().height - 1);
	}

	Shape shape;

	@Override
	public boolean contains(int x, int y) {
		if (shape == null || !shape.getBounds().equals(getBounds())) {
			shape = new Ellipse2D.Float(0, 0, getWidth(), getHeight());
		}
		return shape.contains(x, y);
	}

	public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, UnsupportedLookAndFeelException {

		JFrame frame = new JFrame();
		frame.setTitle("It's all about Java...");
		frame.setSize(150, 150);
		GridLayout layout = new GridLayout();
		layout.setRows(1);
		layout.setHgap(10);
		layout.setVgap(10);
		frame.setLayout(layout);

		JTextField field1 = new JTextField();
		field1.setText("This is a textfield!");
		frame.getContentPane().add(field1);

		RoundedJButton button = new RoundedJButton("Browse");
		button.setBackground(Color.gray);
		button.setForeground(Color.GREEN);
		frame.getContentPane().add(button);

		UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

		SwingUtilities.invokeLater(new Runnable() {
			@Override
			public void run() {
				frame.pack();
				frame.setVisible(true);
			}
		});
	}
}

There are two parts in the program. First part creates RoundedJButton component by extending JButton. and second part creates JFrame and appends two components. 1. RoundedJButton and 2. JTextField

First Part:

RoundedJButton overrides paintComponent(Graphics g) and paintBorder(Graphics g) to get the circled shape to the Button. 

Second Part:

Second part contains main method which creates JFrame object and adds 2 components to JFrame dialog.

Also applies System look and feel by using following

UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

I will explain clearly about pluggable look and feels also known as PLAF in future articles.

That's all for now!

Happy coding... :)