Adapterklassen in Java sind nichts Neues. Sie werden verwendet, um die Implementierung von Listener-Schnittstellen bereitzustellen. Der Vorteil der Adapterklasse besteht darin, dass sie Code spart. Wenn wir die Adapterklasse mithilfe der Adapterschnittstelle erben, sind wir nicht gezwungen, alle Methoden der Listenerschnittstelle zu implementieren. Es gibt nämlich drei Pakete, in denen die Java-Adapterklassen zu finden sind. Die drei Pakete sind:
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Ein weiterer Vorteil der Adapterklasse besteht darin, dass sie nützlich ist, wenn wir einige der Ereignisse verarbeiten möchten, die von einer bestimmten Ereignis-Listener-Schnittstelle verarbeitet werden.
Wie wir in der Einleitung bemerkt haben, gibt es drei Pakete, in denen wir die Adapterklassen finden. Wir werden nun in allen drei Paketen die entsprechende Listener-Schnittstelle der jeweiligen Adapterklassen sehen.
Im Folgenden sind einige der Adapterklassen und ihre entsprechende Listener-Schnittstelle aufgeführt. Diese sind im Abstract Window Toolkit des Java-Pakets vorhanden.
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Listener-Schnittstelle
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| WindowAdapter | WindowListener | ||||||||||||||||||
| KeyAdapter | KeyListener | ||||||||||||||||||
| MouseAdapter | MouseListener | ||||||||||||||||||
| MouseMotionAdapter | MouseMotionListener | ||||||||||||||||||
| FocusAdapter | FocusListener | ||||||||||||||||||
| ComponentAdapter | ComponentListener | ||||||||||||||||||
| ContainerAdapter | ContainerListener | ||||||||||||||||||
| HierarchyBoundsAdapter | HierarchyBoundsListener |
AdapterExample()
{
f=new Frame("Hello World");
f.addWindowListener(new WindowAdapter()
public void windowClosing(WindowEvent e)
{
f.close();
}
}KeyAdapter-Klasse
Der folgende Code gibt die Syntax der KeyAdapter-Klasse an.public abstract keyAdapter Class extends Object Implements KeyListener
MouseAdapter-Klasse
Der folgende Code gibt die Syntax der MouseAdapter-Klasse an.MouseAdapterExample()
{
f=new Frame("Mouse Adapter");
f.addMouseListener(this);
f.setSize(100,100);
f.setLayout(null);
f.setVisible(false);
}MouseMotionAdapter-Klasse
Der folgende Code gibt die Syntax der MouseMotionAdapter-Klasse an.MouseMotionAdapterExample()
{
f=new Frame("Adapter for Mouse Motion");
f.addMouseMotionListener(this);
f.setSize(100,100);
f.setLayout(null);
f.setVisible(false);
}
public void mouseDragged(MouseEvent e)
{
Graphics g=f.getGraphics();
g.setColor(Color.ORANGE);
g.fillOval(e.getX(),e.getY(),20,20);
}FocusAdapter-Klasse
Der folgende Code gibt die Syntax der FocusAdapter-Klasse an.public abstract class FocusAdapter extends Object Implements FocusListener
ComponentAdapter-Klasse
Der folgende Code gibt die Syntax der ComponentAdapter-Klasse an.class MyAdapter extends ComponentAdapter
{
public void componentMoved(ComponentEvent e)
{
int a = e.getComponent().getX();
int b = e.getComponent().getY();
System.out.println("Value of X " + a);
System.out.println("Value of Y: " + b);
}
}ContainerAdapter-Klasse
Der folgende Code gibt die Syntax der ContainerAdapter-Klasse an.public abstract class ContainerAdapter extends Object implements ContainerListener
HierarchyBoundsAdapter-Klasse
Der folgende Code gibt die Syntax der HierarchyBoundsAdapter-Klasse an.public abstract class HierarchyBoundsAdapter extends Object implements HierarchyBoundsListener
| Adapter Class | Listener Interface |
| DragSourceAdapter | DragSourceListener |
| DragTargetAdapter | DragTargetListener |
| Adapterklasse | Listener-Schnittstelle |
| DragSourceAdapter | DragSourceListener |
| DragTargetAdapter | DragTargetListener |
In this case, there are two Adapter classes under the respective package, which is called. We will see the syntax of the two Adapter classes and study the codes under the respective package.
The below code gives the syntax of the DragSourceAdapter class.
Syntax:
public abstract class DragSourceAdapter extends Object implements DragSourceAdapterListener
The below code gives the syntax of the DragTargetAdapter class.
Syntax:
public abstract class DragTargetAdapter extends Object implements DragTargetAdapterListener
Below are some of the classes which are used in the swing. event package. They are listed down in a table.
| Adapter Class | Listener Interface |
| MouseInputAdapter | MouseInputListener |
| InternalFrameAdapter | InternalFrameListener |
In this case, we notice two adapter classes along with their Listener Interface. The package javax. swing. event has two adapter classes which are respectively listed down in the table.
Below is the code which provides the syntax of the MouseInputAdapter class.
Syntax:
public abstract class MouseInputAdapter extends MouseAdapter implements MouseInputListener
Below is the code which provides the syntax of the InternalFrameAdapter class.
Syntax:
public abstract class InternalFrameAdapter extends Object implements InternalFrameListener
Adapter Classes are basically used in the case when the class is declared as abstract. Only the working is based on different functionalities, including the working of the Java classes, which are part of different Java packages. There are three packages in Java that have different Adapter classes and Listener Interfaces along with them. Adapter Classes are used in numerous cases where servers are used, and there is connectivity with the SQL database.
There are different functionalities, and mostly all of them are being used in Android programming as well. Adapter Classes are well-known functionality in Java programming, which helps coders get the idea of many applications that can be used via Swing methodology. There are many ideas that can be put forward to develop the Adapter Class methodology in Java. Loops can also be incorporated to develop some other types of functionality.
In this article, we see the working, and we see that there are three main packages that contain the adapter classes. We see the syntax of all the adapter classes which are present, as well as some of the codes of the working, are also provided. Adapter classes are basically unique in Java, and they are part of Swing functionality in Java.
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