Event Handling in Java

A mechanism used by Java to notify applications that a specific action or change has occurred, often triggered by user interaction or internal system events.

An object containing information about the source of the event and the type of event that occurred. For example: a button being pressed.

A collection of methods used to manage events in a program. Event Listeners are connected to components and wait for specific events to occur, then they execute actions.

A type of event that occurs when a user interacts with a graphical user interface element, such as clicking a button or moving a slider.

A specific type of event generated when the user clicks, presses, or releases a button. Often used to trigger actions in GUI applications.

A type of event that is generated when a component gains or loses focus. Focus indicates which component is currently active and ready to receive user input.

This event occurs when the user manipulates a slider or scrollbar by dragging or moving it.

An anonymous inner class is defined and implemented within another class without a name, used directly where it's needed.

The java.awt.event package provides all the necessary classes and methods for handling events in Java applications.

An event is represented as an object that encapsulates information about a change in state, often triggered by user interactions or system events.

Event delegation is the process where a source object notifies a listener object (an event handler) about a specific event.

The addKeyListener() method is used to attach a KeyListener object to a component, enabling the component to respond to keyboard events like key presses and releases.

You use the addMouseMotionListener() method to attach a MouseMotionListener to a component, allowing it to respond to mouse movements, dragging, and other motion-related events.

A listener is an object that implements specific interfaces and is notified when an event occurs. It's responsible for responding to the event.

The java.util package contains the Event class, which represents the base class for all events in Java.

The getEvent() method allows you to obtain the Event object associated with a specific event, providing information about the event type, source, and other details.

The EventObject class is the superclass of all event classes in Java, providing a common foundation for event handling.

The ItemListener interface is used to handle events related to checkboxes, radio buttons, and lists. It allows you to respond to changes in their selected or deselected states.

The ActionListener interface is used to handle events triggered by buttons, menu items, and other components that generate action events. It allows you to specify the actions to be performed when these components are clicked, selected, or activated.

A push button, a fundamental UI element, has a three-dimensional appearance to visually indicate its clickable state. This three-dimensional effect gives it a raised or recessed look, providing a clear visual cue to the user that it can be interacted with.

The itemStateChanged() method is a key part of the ItemListener interface. It's called whenever the selection state of a component, such as a checkbox or list item, changes. It provides you with the information you need to react to these changes in the user interface.

The TextComponent class is a superclass of both TextField and TextArea classes. It provides a common foundation for creating single-line text fields (TextField) and multiline text areas (TextArea), allowing you to easily manage text input within your Java applications.

A Label is a basic UI element that is mainly used for displaying non-editable text on a window. It helps provide information or labels to other UI components, guiding users and improving the clarity and organization of your application.

The Delegation Event Model promotes a logical approach to handling events in Java. It separates the event source (the object that generates the event) from the event listener (the object that responds to the event). This separation allows for a cleaner and more flexible event handling mechanism.

The Delegation Event Model operates on the principle that an event source generates an event and sends it to one or more listeners that can handle it. This design pattern encourages a clear separation of concerns and promotes loose coupling between different parts of your application.

An applet is a small, self-contained Java program designed to perform a specific task. These tasks can be anything from displaying simple graphics and animations to interacting with users, making them a versatile tool for creating interactive web content. Applet's can be embedded within larger applications or act independently, as long as they adhere to the Java platform's security restrictions.

This method is used to change the location of an event. It moves an event's coordinates to a new position.

This method is used to obtain the WindowEvent object that caused the event for a specific window.

This method is used to get the X coordinate of the mouse pointer's position.

The MouseEvent class is a subclass of the InputEvent class, which handles events related to user input.

The ActionListener interface contains a method called actionPerformed() used to define the action triggered by an event.

This method can be used to determine the type of adjustment event, like changing the value of a slider.

This method returns the value of the adjustment made by the user. It's like knowing how much the slider was moved.

These methods provide a way to handle key presses and releases. They allow your program to respond to user input.

This constant indicates the value when the button on the scrollbar was clicked to increase the value. It usually represents a bigger movement.

When the size of a component changes, this event is generated to notify the program. You can use it to update the layout or resize other components.

This event is generated when a component is added or removed from a container. It helps manage the structure of the user interface.

This method gets a reference to the container that generated a ContainerEvent. It helps identify which container is responsible for the event.

This constant ensures a vertical scrollbar is always visible, no matter the content size.

This method is used to handle the event when a window is about to be closed. This gives you a chance to perform actions before closing the window.

This event is generated when a component gains or loses focus, indicating which component is currently active and ready to receive user input.

FocusEvent is a subclass of InputEvent, which means it inherits properties and methods from the InputEvent class.

This method indicates if the focus change is temporary or permanent. A temporary focus might be lost when the user clicks somewhere else, while a permanent focus remains until the component loses it explicitly.

This method can be used to obtain the coordinates of the mouse pointer. It's useful for knowing precisely where the mouse is located.

ContainerEvent is a subclass of ComponentEvent, which means it inherits properties and methods from the ComponentEvent class. This signifies that ContainerEvents are a specific type of ComponentEvent.