Adapter Classes

In this article we will learn about adapter classes which are used to simplify the event handling process. Sample Java programs are also provided.

Adapter classes are a set of classes which can be used to simplify the event handling process. As we can see in the mouse event handling program here, even though we want to handle only one or two mouse events, we have to define all other remaining methods available in the listener interface(s).

To remove the aforementioned disadvantage, we can use adapter classes and define only the required event handling method(s). Some of the adapter classes available in the java.awt.event package are listed below:

So, the mouse event handling program can be simplified using adapter classes as follows:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class MyApplet extends JApplet
{
	JLabel label;
	public void init()
	{
		setSize(600,300);
		setLayout(new FlowLayout());
		label = new JLabel();
		add(label);
		addMouseListener(new MyAdapter(label));
	}
	
}
class MyAdapter extends MouseAdapter
{
	JLabel label;
	MyAdapter(JLabel label)
	{
		this.label = label;
	}
	public void mouseClicked(MouseEvent me)
	{
		label.setText("Mouse is clicked");
	}
}

Suryateja Pericherla

Suryateja Pericherla, at present is a Research Scholar (full-time Ph.D.) in the Dept. of Computer Science & Systems Engineering at Andhra University, Visakhapatnam. Previously worked as an Associate Professor in the Dept. of CSE at Vishnu Institute of Technology, India.

He has 11+ years of teaching experience and is an individual researcher whose research interests are Cloud Computing, Internet of Things, Computer Security, Network Security and Blockchain.

He is a member of professional societies like IEEE, ACM, CSI and ISCA. He published several research papers which are indexed by SCIE, WoS, Scopus, Springer and others.